95 results on '"Liu, Haijun"'
Search Results
2. The Role of PKM2 in Multiple Signaling Pathways Related to Neurological Diseases.
- Author
-
Zhang, Xiaoping, Lei, Yihui, Zhou, Hongyan, Liu, Haijun, and Xu, Ping
- Abstract
Pyruvate kinase M2 (PKM2) is a key rate-limiting enzyme in glycolysis. It is well known that PKM2 plays a vital role in the proliferation of tumor cells. However, PKM2 can also exert its biological functions by mediating multiple signaling pathways in neurological diseases, such as Alzheimer's disease (AD), cognitive dysfunction, ischemic stroke, post-stroke depression, cerebral small-vessel disease, hypoxic-ischemic encephalopathy, traumatic brain injury, spinal cord injury, Parkinson's disease (PD), epilepsy, neuropathic pain, and autoimmune diseases. In these diseases, PKM2 can exert various biological functions, including regulation of glycolysis, inflammatory responses, apoptosis, proliferation of cells, oxidative stress, mitochondrial dysfunction, or pathological autoimmune responses. Moreover, the complexity of PKM2's biological characteristics determines the diversity of its biological functions. However, the role of PKM2 is not entirely the same in different diseases or cells, which is related to its oligomerization, subcellular localization, and post-translational modifications. This article will focus on the biological characteristics of PKM2, the regulation of PKM2 expression, and the biological role of PKM2 in neurological diseases. With this review, we hope to have a better understanding of the molecular mechanisms of PKM2, which may help researchers develop therapeutic strategies in clinic. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Role of Oxidative Stress in the Occurrence and Development of Cognitive Dysfunction in Patients with Obstructive Sleep Apnea Syndrome.
- Author
-
Zhang, XiaoPing, Zhou, Hongyan, Liu, HaiJun, and Xu, Ping
- Abstract
Obstructive sleep apnea syndrome (OSAS) causes recurrent apnea and intermittent hypoxia at night, leading to several complications such as cognitive dysfunction. However, the molecular mechanisms underlying cognitive dysfunction in OSAS are unclear, and oxidative stress mediated by intermittent hypoxia is an important mechanism. In addition, the improvement of cognitive dysfunction in patients with OSAS varies by different treatment regimens; among them, continuous positive airway pressure therapy (CPAP) is mostly recognized for improving cognitive dysfunction. In this review, we discuss the potential mechanisms of oxidative stress in OSAS, the common factors of affecting oxidative stress and the Links between oxidative stress and inflammation in OSAS, focusing on the potential links between oxidative stress and cognitive dysfunction in OSAS and the potential therapies for neurocognitive dysfunction in patients with OSAS mediated by oxidative stress. Therefore, further analysis on the relationship between oxidative stress and cognitive dysfunction in patients with OSAS will help to clarify the etiology and discover new treatment options, which will be of great significance for early clinical intervention. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
4. Effects of thermophilic and acidophilic microbial consortia on maize wet-milling steeping.
- Author
-
Sun, Yaqin, Xia, Wenjing, Tang, Langjun, Xiu, Zhilong, Jin, Weiwu, Wang, Xiaoyan, Tao, Jin, Liu, Haijun, An, Hongyan, Li, Yi, and Tong, Yi
- Subjects
BIOLOGICAL evolution ,CORNSTARCH ,SCANNING electron microscopes ,BACTERIAL diversity ,COUNTERCURRENT processes ,CORN - Abstract
To understand the ecology of species and promote biotechnology through beneficial strain selection for improving starch yield in maize wet-milling steeping, bacterial diversity and community structure during the counter-current steeping process in a commercial steeping system were characterized and investigated. The microbial diversity in the steeping liquor, which consisted of 16 phyla, 131 families, and 290 genera, was more abundant compared to those present on the surface of unsteeped maize. As the counter-current steeping progressed, exposing newer maize to the older steepwater, Lactobacillus dominated, replacing Rahnella, Pseudomonas, Pantoea, and Serratia. The thermophilic and acidophilic microbial consortia were enriched through adaptive evolution engineering and employed to improve starch yield. Several steeping strategies were evaluated, including water alone, SO
2 alone, mono-culture of B. coagulans, microbial consortia, and a combination of consortium and SO2 . Combining the microbial consortium with SO2 significantly increased the starch yield to, about 66.4 ± 0.5%, a 22% and 46% increase over SO2 alone and the consortium alone, respectively. Scanning electron microscope (SEM) of steeped maize structure indicated that the combination of consortium and SO2 disrupted the protein matrix and widened gaps between starch granules in maize endosperm. This released proteins into the steepwater and left starch granules in the aleurone layer. The steeping strategy of using thermophilic and acidophilic microbial consortium as additives shows potential application as an environmentally friendly alternative to conventional maize steeping procedures. Highlights: Characterization of bacterial diversity in a commercial steeping system. Adaptation of a thermophilic and acidophilic microbial consortium for maize steeping. Development of an environmentally friendly strategy for maize steeping. Consortium combining SO2 leads to 66.4% increase in starch yield. Novel strategy disrupts protein matrix making starch granules to aleurone layer. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
5. Deoxynivalenol Detoxification by a Novel Strain of Pichia kudriavzevii via Enzymatic Degradation and Cell Wall Adsorption.
- Author
-
Xiao, Jiaqi, Tan, Jian, Guo, Ruyi, Dai, Jianying, Xiu, Zhilong, Sun, Yaqin, Liu, Haijun, Li, Yi, Tong, Yi, and Quan, Chunshan
- Abstract
Deoxynivalenol (DON) is a mycotoxin that significantly threatens the food and feed industry. Corn steep liquor (CSL) is an acidic byproduct of the corn starch industry, and DON is concentrated in CSL once the material is contaminated. In this work, a Pichia kudriavzevii strain that could remove DON from CSL was isolated and characterized. The strain P. kudriavzevii E4-205 showed detoxifying activity in a pH range of 4.0~7.0 and temperature of 25~42 °C, and 39.4% DON was reduced by incubating this strain in CSL supernatant diluted by 2-fold (5 μg/mL DON) for 48 h at pH 5.0 and 30 °C. Further mechanism studies showed that P. kudriavzevii E4-205 could adsorb DON by the cell wall and degrade DON by intracellular enzymes with NADH as a cofactor. The degradation product was identified as 3,7,8,15-tetrahydroxyscirpene by liquid chromatography-tandem mass spectrometry. DON adsorption by inactivated cells was characterized, and the adsorption followed pseudo first-order kinetics. This study revealed a novel mechanism by which microbes degrade DON and might serve as a guide for the development of DON biological detoxification methods. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
6. In situ microbially induced Ca-alginate polymeric sealant in calcareous sand and potential engineering applications.
- Author
-
Zhang, Peng, Liu, Ming, Yang, Yang, Liu, Haijun, Gao, Xuecheng, and Cheng, Liang
- Subjects
ALGINATES ,SEALING compounds ,ACTIVATED sludge process ,SAND ,SEWAGE sludge ,SUSPENDED solids ,SODIUM alginate - Abstract
This study presents a novel method for seepage control in calcareous sand using microbially induced Ca-Alginate polymeric sealant, which was achieved by the reaction between supplied alginate and microbially induced Ca
2+ ions directly derived from calcareous sand. This approach includes two steps: (i) microbially induced soluble Ca2+ generated inside the pores of calcareous sand through a bio-acidification process using activated sludge and (ii) reacting with supplied alginate to form Ca-alginate polymeric sealant via the in situ gelation. With the effect of Ca-alginate polymeric sealant, the seepage rate of the calcareous sand was intensely decreased to the level of 10–9 m/s from an initial 10–4 m/s when 5 g/L of alginate was applied. In this way, a low seepage rate of calcareous sand was achieved which was able to remove heavy metal ions and suspended solids from the wastewater sludge. A model test was also carried out to assess the erosion resistance of Ca-alginate treated calcareous sand dam subjected to wave attack. Built on the current research, the proposed polymeric sealant is a promising method for the reduction of seepage, formation barriers for coastal construction on the island, and remediation of specific contaminants. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
7. Simulation and Properties of Ni/W-SiC Composite Coatings by Magnetic Field-Jet Electrodeposition.
- Author
-
Wang, Hui, Liu, Haijun, and Liu, Wenqing
- Subjects
COMPOSITE coating ,ELECTROPLATING ,JETS (Fluid dynamics) ,SURFACE roughness ,SURFACE coatings ,SIMULATION software ,SURFACE morphology - Abstract
As part of this study, the optimal jet plating parameters were analyzed, and COMOL simulation software was used to simulate the magnetic field-jet electrodeposition processing area under various jet deposition conditions. In order to improve the performance of parts and components materials, different jet parameters were used to prepare Ni/W-SiC composite coatings on the surface of Q235 steel using the magnetic field-jet electrodeposition method. The effects of nozzle outlet diameter and jet distance on the flow field and deposition rate in the processing area of Ni/W-SiC composite coatings deposited by magnetic field-jet electrodeposition were studied. When the nozzle outlet diameter was Φ2 mm, Ni/W-SiC composite coatings had a smooth surface and a dense microstructure. The coatings had the lowest surface roughness and the highest coatings thickness; the roughness was 0.45 μm and the thickness of the coating was 0.162 mm. When the jet distance was 2 mm, Ni/W-SiC composite coatings were dense, SiC nanoparticles were uniformly distributed, and the surface morphology of Ni/W-SiC composite was smoother. At this point, the surface roughness of the coatings was at its lowest, measuring 0.31 μm, with a thickness of 0.15 mm. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
8. Effect of Electrodeposition Method on the Abrasion Resistance of Ni-SiC Composite Nanocoatings.
- Author
-
Liu, Haijun, Wang, Hui, and Guo, Xue
- Subjects
MICROHARDNESS ,ABRASION resistance ,CELLULOSE nanocrystals ,NANOCOATINGS ,ELECTROPLATING ,SCANNING electron microscopy ,WEAR resistance - Abstract
This work reports the deposition of Ni-SiC composite nanocoatings (CNCs) on Q235 steel surface through different approaches, including direct current electrodeposition (DCE), pulse current electrodeposition (PCE), and ultrasonic-assisted pulse current electrodeposition (UPCE), respectively. The surface morphology, phase structure, SiC content, and microhardness of Ni-SiC CNCs were investigated via scanning electron microscopy, x-ray diffraction, energy dispersive spectroscopy, microhardness tester, and wear tester respectively. The results indicated that Ni-SiC CNCs fabricated via DCE acquired a porous structure, whereas those fabricated via UPCE exhibited a smooth surface. The diffraction angles of Ni grain were observed at 44.6°, 52.2°, and 78.3°, while the SiC exhibited the diffraction peak at 34.2°, 41.6°, and 59.7°. The UPCE approach yielded the highest SiC content and microhardness values for Ni-SiC CNCs, at 853.6 HV and 8.91 wt.%, respectively. Furthermore, the Ni-SiC CNCs deposited using the UPCE technique had depths of only 14.3 μm, demonstrating the best abrasion resistance. Ni-SiC CNCs produced with UPCE had a compact and fine microstructure with an excellent microhardness value, which effectively prevented surface damage. This study can provide a new method for preparing the nickel-based nanocoatings with excellent wear resistance. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
9. Rheumatoid arthritis with pulmonary accelerated rheumatoid nodules treated by baricitinib: a case-based review.
- Author
-
Liu, Haijun, Li, Qianhua, Long, Kangxia, Xia, Ouyang, Ye, Yufeng, Wang, Hao, and Dai, Lie
- Subjects
- *
RHEUMATOID arthritis , *BARICITINIB , *PULMONARY nodules , *ANTIRHEUMATIC agents , *KINASE inhibitors - Abstract
Pulmonary accelerated rheumatoid nodules (ARN) represent a rare occurrence within the context of rheumatoid arthritis (RA), with conventional treatment typically involving corticosteroids. In this report, we present a unique case of pulmonary ARN managed with baricitinib, a Janus kinase inhibitor. The patient, a 46-year-old woman diagnosed with RA, initially displayed no evident pulmonary nodules upon pulmonary imaging. Her treatment regimen encompassed corticosteroids, methotrexate, and leflunomide. Nevertheless, a chest computed tomography (CT) scan conducted after a year unveiled the presence of multiple bilateral pulmonary nodules. A thoracoscopic biopsy of these nodules confirmed the presence of rheumatoid nodules. Treatment with baricitinib, a Janus kinase inhibitor or synthetic disease-modifying antirheumatic drug (DMARD), effectively reduced the size of the nodules. Our review of 45 articles on ARN published since 1986 found that nine of them reported 13 cases of pulmonary ARN. These nodules may be caused by certain synthetic and biological DMARDs and often present with respiratory symptoms. CT scans typically reveal multiple solid nodules or ground-glass opacities, some of which may have cavities. Treatment customarily involves discontinuing the suspected drugs and administering corticosteroids. This case suggests that Janus kinase inhibitors may be an effective treatment option for ARN. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
10. Heritability of chronic thermal tolerance and genetic correlations with growth traits in the Pacific oyster (Crassostrea gigas).
- Author
-
Chi, Yong, Li, Qi, Xu, Chengxun, Liu, Weiguo, and Liu, Haijun
- Abstract
The increasing seawater temperature during summer months frequently results in severe mortalities in the Pacific oyster Crassostrea gigas around the world, becoming one of the most significant problems challenging the oyster farming industry. In northern China, significant recurrent summer losses of C. gigas have occurred, and its impact on oyster aquaculture has increased in recent years. Selective breeding for improved oyster resistance to high temperature could help to reduce this massive mortality, but the extent of genetic variation underlying this trait is currently unknown. In this study, we constructed 38 full-sib families using the wild C. gigas and estimated the genetic parameters by performing two month-long high-temperature challenge experiments (30 ℃). Experiment 1 was performed in March 2022 followed by experiment 2 in June 2022 (spawning season). In both challenge experiments, there were significant differences in survival among families, suggesting that C. gigas has a different ability to survive under heat stress. Notably, significantly greater mortality was observed for experiment 2, which related to reproductive status and may contribute to additional stress. Thermal tolerance was defined using both binary test survival and time of death traits. Heritability estimates for thermal tolerance were low to moderate (0.16–0.36 for experiment 1 and 0.16–0.33 for experiment 2) using both a Bayesian (MCMCglmm) and a likelihood-based (ASReml-R) approach and estimated heritability of the threshold animal model using ASReml-R (0.16) appeared to be lower compared to MCMCglmm (0.31–0.32). Notably, the genetic and phenotypic correlations for thermal tolerance between two experiments were 0.463 (BS) to 0.491 (TD) and 0.510 (family survival), respectively, which suggested a significant re-ranking of the family breeding values in different time periods. Finally, the genetic and phenotypic correlations were low between growth traits (shell height, shell length, and shell width) and thermal tolerance, suggesting that selection for these traits should be conducted separately. This study reports the first estimation of genetic parameters for chronic thermal tolerance in C. gigas and indicates that this trait is heritable and selective breeding for thermal tolerance is a feasible and promising approach to reduce summer mortality. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
11. Effects of Thermal Deformation and Heat Treatment on Microstructure and Texture of Hot Isostatic Pressured Ti-6Al-4 V Alloy.
- Author
-
Sun, Xudong, Zhang, Jishi, Dai, Xueyan, and Liu, Haijun
- Subjects
MICROSTRUCTURE ,STRAIN rate ,DISLOCATION density ,CRYSTAL grain boundaries ,ALLOYS - Abstract
The effect of thermal deformation and heat treatment on microstructure and texture of Ti-6Al-4 V alloy was investigated. As for the deformed microstructures, the misorientation angle around 60° gradually intensified with the increase of strain. For the strain rate of 0.001 s
−1 , the dislocation density value of the base plane is about twice the dislocation density value of the pyramidal. By TEM analyses, the needle-like α with the thickness of 200-700 nm. Only variants α appear in region III and there are four type variants α. The two subvariants share a similar color to the (110) β to share a crystal plane. The maximum polar density of texture can be reduced by decreasing the strain rate. The preferred grain orientation of 45° direction with CD and 45° direction with ND was enhanced in region III, causing by the β → α' and β → α". For heat treatment at 0.1 s−1 condition, the spheroidization of lamellar α was boundary splitting. As for ST 1050 °C/1 h/WQ, there are discontinued lamellar α clusters near the GBα and acicular martensite in the β grain. After the SAT 1050 °C/1 h/WQ + 530 °C/6 h/AC processing, the fraction of internal lamellar cluster is reduced, and the fine martensite is gradually surrounded by grain boundary α. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
12. Iterative Generation Method of Arc Length Parameterized Curve Tool Path for Surface Machining from Short-Line Tool Path.
- Author
-
Lu, Lei, Han, Jiang, Xia, Lian, Fan, Cheng, Liu, Haijun, and Chen, Shan
- Abstract
To improve the application of the parametric curve tool path in surface machining, a method for generating arc-length parameterized toolpaths based on short-line toolpaths is proposed. The method first uses commercial CAM software to plan the short-line tool path. Then, the machining tool path with smooth continuous features is extracted. The smooth and continuous features are determined according to the chord length of the short-line tool path, and the extraction method is based on Chebyshev's inequality of large numbers. After obtaining the smooth short-line trajectory, the iterative arc-length parameterized curve toolpath generation method is used to fit the discrete short-line toolpath. In the iterative process, the B-spline toolpath with parameterized chord length is obtained first. It is discretized according to the arc length difference information of the chord length B-spline. Finally, by continuously checking and inserting B-spline nodes, and fitting according to discrete points, the arc-length parameterized B-spline tool path is obtained. The feasibility of the method is verified with a part containing a sculpted surface, and two smooth arc-length parametric toolpaths are generated. In the end, the part is machined with the arc-length parameterized curve tool path. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
13. Biochemical and spectroscopic characterizations of the oligomeric antenna of the coral symbiotic Symbiodiniaceae Fugacium kawagutii.
- Author
-
Niedzwiedzki, Dariusz M., Magdaong, Nikki Cecil M., Su, Xinyang, and Liu, Haijun
- Abstract
Light-harvesting antennas in photosynthesis capture light energy and transfer it to the reaction centers (RCs) where photochemistry takes place. The sustainable growth of the reef-building corals relies on a constant supply of the photosynthates produced by the endosymbiotic dinoflagellate, belonging to the family of Symbiodiniaceae. The antenna system in this group consists of the water-soluble peridinin-chlorophyll a-protein (PCP) and the intrinsic membrane chlorophyll a-chlorophyll c
2 -peridinin protein complex (acpPC). In this report, a nonameric acpPC is reported in a dinoflagellate, Fugasium kawagutii (formerly Symbiodinium kawagutii sp. CS-156). We found that extensive biochemical purification altered the oligomerization states of the initially isolated nonameric acpPC. The excitation energy transfer pathways in the acpPC nonamer and its variants were studied using time-resolved fluorescence and time-resolved absorption spectroscopic techniques at 77 K. Compared to the well-characterized trimeric acpPC, the nonameric acpPC contains an 11 nm red-shifted terminal energy emitter and substantially altered excited state lifetimes of Chl a. The observed energetic overlap of the fluorescence terminal energy emitters with the absorption of RCs is hypothesized to enable efficient downhill excitation energy transfer. Additionally, the shortened Chl a fluorescence decay lifetime in the oligomeric acpPC indicate a protective self-relaxation strategy. We propose that the highly-oligomerized acpPC nonamer represents an intact functional unit in the Symbiodiniaceae thylakoid membrane. They perform efficient excitation energy transfer (to RCs), and are under manageable regulations in favor of photoprotection. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
14. Multi-strategies Boosted Mutative Crow Search Algorithm for Global Tasks: Cases of Continuous and Discrete Optimization.
- Author
-
Shan, Weifeng, Hu, Hanyu, Cai, Zhennao, Chen, Huiling, Liu, Haijun, Wang, Maofa, and Teng, Yuntian
- Published
- 2022
- Full Text
- View/download PDF
15. Molecular asymmetry of a photosynthetic supercomplex from green sulfur bacteria.
- Author
-
Puskar, Ryan, Du Truong, Chloe, Swain, Kyle, Chowdhury, Saborni, Chan, Ka-Yi, Li, Shan, Cheng, Kai-Wen, Wang, Ting Yu, Poh, Yu-Ping, Mazor, Yuval, Liu, Haijun, Chou, Tsui-Fen, Nannenga, Brent L., and Chiu, Po-Lin
- Subjects
SULFUR bacteria ,CYTOCHROME c ,ENERGY transfer ,MEMBRANE separation ,ELECTRON microscopy ,CHLOROPHYLL spectra - Abstract
The photochemical reaction center (RC) features a dimeric architecture for charge separation across the membrane. In green sulfur bacteria (GSB), the trimeric Fenna-Matthews-Olson (FMO) complex mediates the transfer of light energy from the chlorosome antenna complex to the RC. Here we determine the structure of the photosynthetic supercomplex from the GSB Chlorobaculum tepidum using single-particle cryogenic electron microscopy (cryo-EM) and identify the cytochrome c subunit (PscC), two accessory protein subunits (PscE and PscF), a second FMO trimeric complex, and a linker pigment between FMO and the RC core. The protein subunits that are assembled with the symmetric RC core generate an asymmetric photosynthetic supercomplex. One linker bacteriochlorophyll (BChl) is located in one of the two FMO-PscA interfaces, leading to differential efficiencies of the two energy transfer branches. The two FMO trimeric complexes establish two different binding interfaces with the RC cytoplasmic surface, driven by the associated accessory subunits. This structure of the GSB photosynthetic supercomplex provides mechanistic insight into the light excitation energy transfer routes and a possible evolutionary transition intermediate of the bacterial photosynthetic supercomplex from the primitive homodimeric RC. Cryo-EM reveals an asymmetric bacterial photosynthetic supercomplex built upon a homodimeric reaction center core. The structure provides mechanistic insights into light excitation transfer and a possible evolutionary transition intermediate of photosynthetic machinery. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
16. Psb27, a photosystem II assembly protein, enables quenching of excess light energy during its participation in the PSII lifecycle.
- Author
-
Johnson, Virginia M., Biswas, Sandeep, Roose, Johnna L., Pakrasi, Himadri B., and Liu, Haijun
- Abstract
Photosystem II (PSII), the enzyme responsible for oxidizing water into molecular oxygen, undergoes a complex lifecycle during which multiple assembly proteins transiently bind to and depart from PSII assembly intermediate complexes. Psb27 is one such protein. It associates with the CP43 chlorophyll-binding subunit of PSII to form a Psb27-PSII sub-complex that constitutes 7–10% of the total PSII pool. Psb27 remains bound to PSII assembly intermediates and dissociates prior to the formation of fully functional PSII. In this study, we compared a series of Psb27 mutant strains in the cyanobacterium Synechocystis sp. PCC 6803 with varied expression levels of Psb27: wild type (WT); psb27 genetic deletion (Del27), genetically complemented psb27 (Com27); and over-expressed Psb27 (OE27). The Del27 strain demonstrated decreased non-photochemical fluorescence quenching, while the OE27 strain showed increased non-photochemical quenching and tolerance to fluctuating light conditions. Multiple flashes and fluorescence decay analysis indicated that OE27 has the least affected maximum PSII quantum yield of the mutants. OE27 also displayed a minimal impact on the half-life of the fast component of Q
A – reoxidation over multiple flashes, indicating robust PSII function. We propose that the close association between Psb27 and CP43, and the absence of a fully functional manganese cluster in the Psb27-PSII complex create a PSII sub-population that dissipates excitation energy prior to its recruitment into the functional PSII pool. Efficient energy dissipation prevents damage to this pre-PSII pool and allows for efficient PSII repair and maturation. Participation of Psb27 in the PSII life cycle ensures high-quality PSII assembly. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
17. Drip irrigation enhances water use efficiency without losses in cucumber yield and economic benefits in greenhouses in North China.
- Author
-
Liu, Haijun, Yuan, Baozhong, Hu, Xiaodong, and Yin, Congyan
- Subjects
- *
MICROIRRIGATION , *WATER efficiency , *IRRIGATION water , *FURROW irrigation , *CUCUMBERS , *COVID-19 , *GREENHOUSE plants , *IRRIGATION farming - Abstract
The cultivation mode of planting offseason crops, such as cucumber, with drip irrigation has been widely used in greenhouses in North China to achieve high yields, obtain large economic benefits, and improve water use efficiency. The objectives of this study were to evaluate the effects of drip irrigation on the irrigation water amount, irrigation water use efficiency (IWUE), and cucumber yield and the corresponding economic benefits. These objectives were achieved using data from a seven-season experiment in a commercial greenhouse with cucumber plants in North China. Local furrow irrigation was used as the control. The results showed that the cucumber yields and income with drip irrigation were 4.3% and 3.1% higher than those under furrow irrigation, respectively. However, the seasonal total irrigation depth for drip irrigation was approximately 50% lower than that for furrow irrigation. The IWUE averaged 0.41 in furrow irrigation but increased to 0.79 in drip irrigation. The irrigation water productivity and the economic irrigation water productivity for drip irrigation were approximately 100% higher than those for furrow irrigation. The mean economic irrigation water productivity was 19.8 US$ m−3 for drip irrigation, which is 7 times higher than the 2019 value of 2.7 US$ m−3 in the agricultural sector in China, indicating potential high economic benefits. In conclusion, drip irrigation is recommended in greenhouses to reduce irrigation water by approximately 50% and increase cucumber yield and economic benefits by approximately 3–4% compared to traditional furrow irrigation in North China. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
18. Accelerated kinetics of alkaline hydrogen evolution/oxidation reactions on dispersed ruthenium sites through N and S dual coordination.
- Author
-
Zhang, Zhen, Ni, Liwen, Liu, Haijun, Zhao, Zhi-Liang, Yuan, Xiao-Zi, and Li, Hui
- Abstract
Efficient, robust and cost-effective electrocatalysts that catalyze hydrogen evolution/oxidation reaction (HER/HOR) in alkaline media are highly demanded. Recently, single-atom catalysts (SACs) have emerged as new promising candidates; however, the rational design of supports and the optimization of coordination environment between supports and metal atoms are challenging. In this work, we successfully fabricate atomically dispersed ruthenium (Ru) species, which are strongly coordinated by N and S dual heteroatoms on holey graphene (RuSA/NSG), as an excellent bifunctional catalyst for HER/HOR. In alkaline media, the developed catalyst exhibits high catalytic performance with a low overpotential of 57.3 mV to drive a current density of 10 mA cm
−1 for HER, and its mass activity is about 5.8 times higher than that of commercial Pt/C and Ru/C catalysts at an overpotential of 100 mV. Similarly, considerable HOR performance of RuSA/NSG is verified to be superior to Pt/C and Ru/C. Furthermore, X-ray-based spectroscopy measurements and density-functional theory calculations have confirmed that, compared with Ru-N4 , the tailored Ru-N4 -S2 with nearby S dopants can act as more active centers to greatly accelerate the sluggish HER/HOR kinetics in alkaline media. The present work provides a new atomic-level engineering strategy to modulate catalytic activities of SACs via the coordination design using dual heteroatoms on the carbon support. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
19. Ionic liquid-based multi-stage sugaring-out extraction of lactic acid from simulated broth and actual lignocellulosic fermentation broth.
- Author
-
Zhou, Xu, Sun, Yaqin, Zhan, Hongjun, Liu, Haijun, Wang, Xiaoyan, Xu, Yang, Li, Yi, Xiu, Zhilong, and Tong, Yi
- Subjects
LACTIC acid ,FERMENTATION ,CORN stover ,SACCHARIDES ,CHROMATOPHORES ,PHASE partition - Abstract
In this study, ionic liquid-based sugaring-out extraction was developed to separate lactic acid from the synthetic solution and actual lignocellulosic fermentation broth. Except for [E
OH mim]BF4 , the ILs with BF4 − and OTF− anion can form aqueous two-phase system (ATPS) with the aid of saccharides. With the same kind of saccharides, the ATPS formation ability of ILs could be promoted by increasing the side-chain length of ILs in the order of [Hmim]BF4 ≈ [Bmim]BF4 ˃ [Emim]BF4 due to the decrease in ILs' kosmotropicity. On the other hand, for the same type of ILs, an ATPS was formed more easily with glucose than with xylose. When IL concentration varied from 35% (w/w) to 40% (w/w) at a low glucose concentration of 15% (w/w), an interesting phase reversal was observed. When lactic acid was undissociated at pH 2.0, 51.8% LA and 92.3% [Bmim]BF4 were partitioned to the top phase, and 97.0% glucose to the bottom phase using an ATPS consisting of 25% (w/w) glucose and 45% (w/w) IL. The total recovery of LA would increase to 89.0% in three-stage sugaring-out extraction from synthetic solution. In three-stage sugaring-out extraction from the filtered and unfiltered fermentation broth obtained via simultaneous saccharification and co-fermentation (SSCF) of acid-pretreated corn stover by the microbial consortium, the total recovery of LA was 89.5% and 89.8%, respectively. Furthermore, the total removal ratio of cells and pigments from the unfiltered broth was 68.4% and 65.4%, respectively. The results support IL-based sugaring-out extraction as a potential method for the recovery of lactic acid from actual fermentation broth. Highlights: IL-based sugaring-out extraction was applied to separate LA from fermentation broth Different ILs and saccharides consisting systems were examined The ability to form ATPS is in the order of [Hmim]BF4 ≈ [Bmim]BF4˃[Emim]BF4 The partition behaviors of LA, [Bmim]BF4, and saccharides were evaluated LA recovery of 89.8% was obtained with removal of 68.4% cells and 65.4% pigments [ABSTRACT FROM AUTHOR]- Published
- 2021
- Full Text
- View/download PDF
20. Multi-pass Hot Deformation Behavior and Microstructure Evolution of Spark Plasma-Sintered Ti-6Al-4V Alloy.
- Author
-
Xue, Yong, Zhang, Jishi, Liu, Haijun, Yan, Zhaoming, Zhao, Hongyue, Xu, Jian, Yang, Yaqing, Wang, Qiang, and Zhang, Zhimin
- Subjects
MICROSTRUCTURE ,STRAINS & stresses (Mechanics) ,MATERIAL plasticity ,DEFORMATIONS (Mechanics) ,GRAIN size ,TITANIUM alloys - Abstract
The spark plasma-sintered Ti-6Al-4V alloy was used as experimental specimens to perform the multi-pass hot compression. The deformation temperature was 950, 900, 850 °C, and the compressed amount was 20, 30, 20% corresponding to one pass, two passes and three passes, respectively. The flow behaviors revealed that the curve with the strain rate of 5 s
−1 appeared obvious oscillatory phenomenon after peak. Additionally, the curve with strain rate of 0.1 and 1 s−1 almost kept constant after peak stress during the process of two-pass compression. The microstructures showed that the sintered voids with the average diameter of 7.53 μm could be observed in initial Widmanstatten structures with the aspect ratio of 11.49 ± 0.5. The deformed inhomogeneity had prominent influence on the microstructures. For three-pass deformation with the strain rate of 0.1 s−1 , the microstructures of severe plastic deformation area were equiaxial microstructures with the grain diameter of 3.82 μm, while the microstructures for medial and small plastic deformation area were dual and Widmanstatten, respectively. With the strain rate of 0.1 s−1 , the fraction of dynamic recrystallization (fDRX ) increased from 0.034 through 0.112 to 0.440 with the passes increased, and the variation tendency toward average diameter of grain size versus compressed passes shifted reversely. The β→α phase transformation was the main reason for the misorientation angle nearby 60° for one pass with the strain rate of 0.1 s−1 . The fDRX declined from 0.440 through 0.225 to 0.297 with raising the strain rate for three-pass deformation, but the grain size changed oppositely. The CDRX and DDRX were both appeared during multi-pass hot deformation. [ABSTRACT FROM AUTHOR]- Published
- 2021
- Full Text
- View/download PDF
21. Theoretical study on flow and radiation in tubular solar photocatalytic reactor.
- Author
-
Wei, Qingyu, Wang, Yao, Dai, Bin, Yang, Yan, Liu, Haijun, Yuan, Huaijie, Jing, Dengwei, and Zhao, Liang
- Abstract
In this paper, based on the mixture flow model, an optimized six-flux model is first established and applied to the tubular solar photocatalytic reactor. Parameters influencing photocatalyst distribution and radiation distribution at the reactor outlet, viz. catalyst concentration and circulation speed, are also analyzed. It is found that, at the outlet of the reactor, the optimized six-flux model has better performances (the energy increase by 1900% and 284%, respectively) with a higher catalyst concentration (triple) and a lower speed (one third). [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
22. Effects of taping on grinding quality of silicon wafers in backgrinding.
- Author
-
Dong, Zhigang, Zhang, Qian, Liu, Haijun, Kang, Renke, and Gao, Shang
- Abstract
Taping is often used to protect patterned wafers and reduce fragmentation during backgrinding of silicon wafers. Grinding experiments using coarse and fine resinbond diamond grinding wheels were performed on silicon wafers with tapes of different thicknesses to investigate the effects of taping on peak-to-valley (PV), surface roughness, and subsurface damage of silicon wafers after grinding. Results showed that taping in backgrinding could provide effective protection for ground wafers from breakage. However, the PV value, surface roughness, and subsurface damage of silicon wafers with taping deteriorated compared with those without taping although the deterioration extents were very limited. The PV value of silicon wafers with taping decreased with increasing mesh size of the grinding wheel and the final thickness. The surface roughness and subsurface damage of silicon wafers with taping decreased with increasing mesh size of grinding wheel but was not affected by removal thickness. We hope the experimental finding could help fully understand the role of taping in backgrinding. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
23. An experimental study and mechanism analysis on improving dispersion stability performance of Al2O3 nanoparticles in base synthetic oil under various mixing conditions.
- Author
-
Hou, Xianjun, Liu, Haijun, Li, Xiaoxue, Jiang, Hua, Tian, Zekun, and Ali, Mohamed Kamal Ahmed
- Abstract
The main goal of this study is to improve the dispersion stability of Al2O3 nanoparticles in polyalphaolefin oil to overcome the sedimentation problem of nanoparticles using the addition of oleic acid as a surfactant. Based on the previous single or insufficient research on the preparation conditions of nanolubricating oil, the effects of temperature, ultrasonic duration, ultrasonic power, and nanoparticle/surfactant (oleic acid) concentration on the dispersion stability of Al2O3 nanoparticles (size range of about 50nm) in oil-based solutions were systematically and comprehensively studied in this work. Herein, the preparation conditions were optimized and the stable nanofluids were obtained. The visual observation, UV–Vis spectroscopy, and dynamic light scattering (DLS) analysis were used to evaluate the dispersion stability of the Al2O3 nanoparticles. Moreover, the dispersion state of Al2O3 in PAO6 solution was demonstrated through transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) at a microscopic level, and the mechanism of dispersion stability was analyzed. The results reveal that the thermal method during the synthesis of nanofluids using 50°C temperature improves the dispersion of nanoparticles. The results also exhibited that there is an optimal match between the ultrasonication power and the ultrasonication duration during the synthesis of nanofluids, which affects its dispersion stability. The results showed that 0.4%wt% oleic acid was needed for the nanolubricants containing 0.005wt% and 0.01wt% to achieve excellent dispersion stability, and the stabilization time exceeds 160 days. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
24. Spatial-temporal distribution of climate suitability of winter wheat in North China Plain for current and future climate scenarios.
- Author
-
Tang, Xiaopei and Liu, Haijun
- Subjects
- *
WINTER wheat , *SOLAR radiation , *FUZZY mathematics , *CLIMATE change , *PLAINS , *FOOD security - Abstract
Wheat production in the North China Plain (NCP) is critical to food security in China; however, it is affected by climate change. Understanding the spatiotemporal distribution of climate suitability of wheat in NCP may help to rationally use climatic resources as well as reduce natural disasters. Out of 30 general circulation models in the Coupled Model Intercomparison Project Phase 5, the 5 best GCMs were selected for each meteorological factor to project daily data in 2021–2100 under representative concentration path 4.5 (RCP4.5) and RCP8.5 for 23 national climatic stations in NCP. Based on agricultural climatic suitability theory and the fuzzy mathematics method, the suitability of water, temperature, and solar radiation was analyzed. The results showed that the water suitability increases from 0.30 at present to 0.40 for 2021–2100 under both RCP4.5 and RCP8.5 with the lowest mostly distributed in the northwest. The temperature suitability varies from 0.80 at present to 0.75 for 2021–2100 and generally increases from north to south; however, at stage 2 (from overwintering to greening), it drops from 0.67 to 0.50 under RCP4.5 and 0.20 under RCP8.5 for 2081–2100. The decreases of water suitability at stage 5 (from heading to milking) and temperature suitability at stage 2 show negative effect of climate change to winter wheat. The solar radiation suitability shows an increasing trend under two scenarios in the future. Finally, the integrated climate suitability shows a little increasing trend, indicating climate condition of winter wheat in NCP will be slightly improved. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
25. Ni-SiC Composite Coatings with Good Wear and Corrosion Resistance Synthesized Via Ultrasonic Electrodeposition.
- Author
-
Wang, Hui, Liu, Haijun, He, Yang, Ma, Chunyang, and Li, Liangzhao
- Subjects
COMPOSITE coating ,CORROSION resistance ,WEAR resistance ,X-ray photoelectron spectroscopy ,ABRASION resistance ,ATOMIC force microscopy ,MICROHARDNESS testing ,TRIBO-corrosion - Abstract
Ni-SiC composite coatings with good wear and corrosion resistance could be obtained by the ultrasonic electrodeposition (UED) method in this study. The microstructure, microhardness, corrosion and abrasion resistance, and sectional composition distribution of the composite coatings were investigated employing atomic force microscopy (AFM), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), electrochemical workstation, Vickers microhardness testing, and wear testing. In addition, the statistical distributions of Ni grains in Ni coating and Ni-SiC composites were counted by using a "Nano Measurer" software. The outcome of AFM and HRTEM revealed a compact surface structure of Ni-SiC composite coating made by the UED. The mean diameter of Ni crystals was 68.4 nm, whereas that of SiC nanoparticles present within the composite was 26.7 nm. According to the XPS data, the content of Si in the Ni-SiC composite coating prepared via UED was approximately 23.7 at.% whereas that of Ni was about 46.8 at.%. The Ni-SiC composite coating deposited via UED method was found to have the largest value for microhardness (715.7 HV) compared to other coatings, although the nickel coating had a mean microhardness of 485.8 HV only. The I
corr and Ecorr values of the Ni-SiC composite coating deposited via UED were 1.13 × 10−3 mA/cm2 and − 0.311 V, respectively, indicating an optimal level corrosion resistance. Besides, the surface morphological analysis of the coating revealed that it was glossy with only minor surface scratches, and it exhibited the best resistance to wear. [ABSTRACT FROM AUTHOR]- Published
- 2021
- Full Text
- View/download PDF
26. RP11-462C24.1 suppresses proliferation and invasion of colorectal carcinoma cells by regulating HSP70 through PI3K/AKT signaling pathway.
- Author
-
Zhang, Haiqing, Zhang, Guangjun, Liu, Haijun, Shan, Yuanzhou, and Zhang, Xueli
- Subjects
COLON cancer ,HEAT shock proteins ,CELL cycle ,CELLS ,TUMOR growth - Abstract
Colorectal cancer (CRC) is the third leading cause of cancer-related death around the world. In this study, we investigated the roles of LncRNA RP11-462C24.1 in CRC. The expressions of RP11-462C24.1 in CRC tissues and cells were measured. Then, the effects of RP11-462C24.1 on CRC proliferation, cell cycle, apoptosis, and invasion were evaluated both in vivo and in vitro; Last, the underlying mechanisms of concerning the signaling pathway regulated by RP11-462C24.1 was determined. From the results, we found that RP11-462C24.1 was significantly decreased in CRC tumor tissues and the CRC cell lines, which were most significant in SW480 and HT-29 cell lines; moreover, transient overexpression of RP11-462C24.1 suppressed the growth and migration while promoted apoptosis of SW480 and HT-29 cells, while knockdown of RP11-462C24.1 has shown the opposite effects; RP11-462C24.1 may also inhibit the growth of CRC tumors in xenograft mice models; additionally, 70 kD heat shock proteins (HSP70) has been identified as one of the most significantly deferentially expressed genes by RNA-seq, and we further confirmed that RP11-462C24.1 may affect the growth and metathesis of CRC cells via regulating HSP70 and PI3K/AKT signaling pathway. In summary, these results indicated that RP11-462C24 may function as a tumor suppressor in the development of CRC. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
27. A decoupled five-axis local smoothing interpolation method to achieve continuous acceleration of tool axis.
- Author
-
Jiang, Yang, Han, Jiang, Xia, Lian, Lu, Lei, Tian, Xiaoqing, and Liu, Haijun
- Subjects
CAD/CAM systems ,INTERPOLATION ,HIGH-speed machining ,IMPULSE response ,SIMPLE machines ,MACHINE tools - Abstract
Five-axis machines are widely used in high-speed and high-precision machining of complex sculptured surfaces for the ability to adjust the tool orientation. But, most of the five-axis machining trajectories generated by computer-aided manufacturing (CAM) software are G01 blocks in the form of a large number of linear segments. The G01 blocks for surface machining show inadequacies as their high-order discontinuities. Although there are a lot of researches to deal with the discontinuities, there are still many problems such as smoothing error control, motion synchronization, kinematic constraints limitation. Besides, the kinematic constraints of the tool orientation motion are always neglected. In this paper, a two-step real-time decoupling local smoothing method is proposed for the problem of the five-axis tool path smoothing. The C
2 continuity of the tool path is guaranteed within the error limited. Not only the kinematic constraints of tool tip motion but also the kinematic constraints of the tool orientation motion are considered. The continuous acceleration of each axis motion of the machine tool is realized through feed-rate scheduling by finite impulse response (FIR) filtering. Finally, through numerical simulations and experiments, compared with the existing method and G01 linear interpolation, it is verified that the proposed smoothing interpolation method has a higher computation efficiency and can improve the processing efficiency and surface quality of the tool path while satisfying the specified smoothing error constraints and kinematic constraints. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
- View/download PDF
28. FEM-based optimization approach to machining strategy for thin-walled parts made of hard and brittle materials.
- Author
-
Liu, Zhiqiang, Kang, Renke, Liu, Haijun, Dong, Zhigang, Bao, Yan, Gao, Shang, and Zhu, Xianglong
- Subjects
HARD materials ,FINITE element method ,BRITTLE materials ,MACHINE parts ,SURFACE finishing - Abstract
Thin-walled parts are widely used in the aerospace, automotive, and medical industries. High machining efficiency is desired as much of the material needs to be removed. The aggressive machining strategies are often applied but tend to cause poor surface finish, inadequate machining tolerance, and even fracture of workpiece. Thus, it is of vital importance to adopt reasonable machining strategy and choose accurate machining parameters considering of both the machining efficiency and quality. In this paper, an optimization approach to enhance machining efficiency for thin-walled parts made of hard and brittle material without compromising machining quality was proposed. The core idea of the proposed approach is to minimize the maximum stress of the thin-walled part during machining by optimizing the workpiece shape based on finite element method (FEM). The stiffness of the thin-walled parts during machining retains high while the machining induced deformation is small. The optimization approach was experimentally validated on K9 glass, and the maximum deformation of the thin-walled part for the optimal machining strategy decreases significantly compared with that of traditional machining strategy and the total machining time is reduced by 44%. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
29. Revisiting high-resolution crystal structure of Phormidium rubidum phycocyanin.
- Author
-
Sonani, Ravi R., Roszak, Aleksander W., Liu, Haijun, Gross, Michael L., Blankenship, Robert E., Madamwar, Datta, and Cogdell, Richard J.
- Abstract
The crystal structure of phycocyanin (pr-PC) isolated from Phormidium rubidum A09DM (P. rubidum) is described at a resolution of 1.17 Å. Electron density maps derived from crystallographic data showed many clear differences in amino acid sequences when compared with the previously obtained gene-derived sequences. The differences were found in 57 positions (30 in α-subunit and 27 in β-subunit of pr-PC), in which all residues except one (β145Arg) are not interacting with the three phycocyanobilin chromophores. Highly purified pr-PC was then sequenced by mass spectrometry (MS) using LC–MS/MS. The MS data were analyzed using two independent proteomic search engines. As a result of this analysis, complete agreement between the polypeptide sequences and the electron density maps was obtained. We attribute the difference to multiple genes in the bacterium encoding the phycocyanin apoproteins and that the gene sequencing sequenced the wrong ones. We are not implying that protein sequencing by mass spectrometry is more accurate than that of gene sequencing. The final 1.17 Å structure of pr-PC allows the chromophore interactions with the protein to be described with high accuracy. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
30. A Novel Research on the Influence of Enterprise Culture on Internal Control in big Data and Internet of Things.
- Author
-
Liu, Haijun and Liu, Xiaobing
- Subjects
- *
INTERNET of things , *BIG data , *INTERNAL auditing , *WIRELESS sensor nodes , *RESOURCE management - Abstract
The effective management of enterprise resources in internet of things is a growing research trend in modern era. The big data concept influences more opportunities to the researchers to exhibit their innovations in various application oriented fields. The academic and organizational researches suggested that big data provides more benefits on sustained basis for the committed resource management environment. The study shows positive and active enterprise culture is positively correlated to effective internal control. In the enhancement of these resource management initiatives, the dynamic capability of the data and its assumptions are considered. In the case of enterprise culture the implication of practical and business limitations and advantages are discussed in this article. The intellectual contributions and the poles of excellence on the field of big data is a common platform upon which several communication components in practice on every day use which are interfaced and interconnected. In general IoT reduces the distance between the real world and internet by incorporating and integrating different perspectives of technology such as pervasive computing, data communication, networking, sensor node communication etc., [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
31. Photoactivation and relaxation studies on the cyanobacterial orange carotenoid protein in the presence of copper ion.
- Author
-
Liu, Haijun, Lu, Yue, Wolf, Benjamin, Saer, Rafael, King, Jeremy D., and Blankenship, Robert E.
- Abstract
Photosynthesis starts with absorption of light energy by light-harvesting antenna complexes with subsequent production of energy-rich organic compounds. However, all photosynthetic organisms face the challenge of excess photochemical conversion capacity. In cyanobacteria, non-photochemical quenching (NPQ) performed by the orange carotenoid protein (OCP) is one of the most important mechanisms to regulate the light energy captured by light-harvesting antennas. This regulation permits the cell to meet its cellular energy requirements and at the same time protects the photosynthetic apparatus under fluctuating light conditions. Several reports have revealed that thermal dissipation increases under excess copper in plants. To explore the effects and mechanisms of copper on cyanobacteria NPQ, photoactivation and relaxation of OCP in the presence of copper were examined in this communication. When OCP (OCP at orange state) is converted into OCP(OCP at red state), copper ion has no effect on the photoactivation kinetics. Relaxation of OCP to OCP, however, is largely delayed-almost completely blocked, in the presence of copper. Even the addition of the fluorescence recovery protein (FRP) cannot activate the relaxation process. Native polyacrylamide gel electrophoresis (PAGE) analysis result indicates the heterogeneous population of Cu-locked OCP. The Cu-OCP binding constant was estimated using a hyperbolic binding curve. Functional roles of copper-binding OCP in vivo are discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
32. Effects of regulated deficit irrigation on yield and water productivity of chili pepper ( Capsicum annuum L.) in the arid environment of Northwest China.
- Author
-
Yang, Huiying, Liu, Haijun, Zheng, Jianhua, and Huang, Quanzhong
- Subjects
- *
WATER supply , *IRRIGATION , *HOT peppers , *SUSTAINABLE agriculture - Abstract
Due to the scarcity of water resources in Northwest China, the use of deficit irrigation scheduling is beneficial for sustainable agricultural development. Therefore, a 2-year field experiment was performed to investigate the effects of regulated deficit irrigation (RDI) on the yield and water productivity (WP) of drip-irrigated chili pepper plants in a typical arid environment of Northwest China. The results indicate that RDI strategies reduced actual crop evapotranspiration by 2-27%. Crop coefficients for chili pepper averaged 0.85, 1.09 and 0.84 for the development, middle and late stages, respectively. The highest yield occurred under full irrigation. The largest yield reduction (13-20%) was recorded when water deficit occurred during the middle stage. Fifty percent water deficit reduced yields more than 25% water deficit did. The highest irrigation water productivity and WP were achieved when water deficit occurred during the late stage. RDI may improve fruit quality by increasing the content of total soluble solids of the fresh fruit. In conclusion, full irrigation is recommended first for achieving the highest yield, and a water deficit of 25-50% during the late stage is also recommended if considering economic benefits and WP in the study region. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
33. Subcellular pigment distribution is altered under far-red light acclimation in cyanobacteria that contain chlorophyll f.
- Author
-
Majumder, Erica, Wolf, Benjamin, Liu, Haijun, Berg, R., Timlin, Jerilyn, Chen, Min, and Blankenship, Robert
- Abstract
Far-Red Light (FRL) acclimation is a process that has been observed in cyanobacteria and algae that can grow solely on light above 700 nm. The acclimation to FRL results in rearrangement and synthesis of new pigments and pigment-protein complexes. In this study, cyanobacteria containing chlorophyll f, Synechococcus sp. PCC 7335 and Halomicronema hongdechloris, were imaged as live cells with confocal microscopy. H. hongdechloris was further studied with hyperspectral confocal fluorescence microscopy (HCFM) and freeze-substituted thin-section transmission electron microscopy (TEM). Under FRL, phycocyanin-containing complexes and chlorophyll-containing complexes were determined to be physically separated and the synthesis of red-form phycobilisome and Chl f was increased. The timing of these responses was observed. The heterogeneity and eco-physiological response of the cells was noted. Additionally, a gliding motility for H. hongdechloris is reported. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
34. Impact of threshold voltage variation on 1S1R crossbar array with threshold switching selectors.
- Author
-
Song, Bing, Xu, Hui, Liu, Haijun, and Li, Qingjiang
- Subjects
NONVOLATILE random-access memory ,RANDOM access memory ,SEMICONDUCTOR storage devices ,ELECTRIC potential ,ELECTROSTATICS - Abstract
It is important that selector achieves voltage compatibility with paired resistive random access memory element. Nevertheless, unsatisfactory uniformity existing in practical selector devices will lead to serious problems during operation. This paper investigates the potential impact of threshold voltage variation on crossbar array with one-selector one-resistor cell. We prove that large variation of threshold voltage may lead to unintentional writing during read process. Therefore, we propose a method to determine selectors' threshold voltage range within 1/2 or 1/3 bias scheme. Results indicate tolerable threshold voltage range basically expands with the increasing OFF-resistance or decreasing ON-resistance of selectors. The proposed method gives a guideline for choosing and fabricating appropriate selectors for RRAM elements with specific parameters. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
35. Roux-en-Y Gastric Bypass Surgery Suppresses Hepatic Gluconeogenesis and Increases Intestinal Gluconeogenesis in a T2DM Rat Model.
- Author
-
Yan, Yong, Zhou, Zhou, Kong, Fanzhi, Feng, Suibin, Li, Xuzhong, Sha, Yanhua, Zhang, Guangjun, Liu, Haijun, Zhang, Haiqing, Wang, Shiguang, Hu, Cheng, and Zhang, Xueli
- Subjects
GASTRIC bypass ,GLUCONEOGENESIS ,INTESTINAL diseases ,LABORATORY rats ,HIGH-fat diet ,STREPTOZOTOCIN ,METABOLIC regulation ,PREVENTION - Abstract
Background: Roux-en-Y gastric bypass (RYGB) is an effective surgical treatment for type 2 diabetes mellitus (T2DM). The present study aimed to investigate the effects of RYGB on glucose homeostasis, lipid metabolism, and intestinal morphological adaption, as well as hepatic and intestinal gluconeogenesis. Methods: Twenty adult male T2DM rats induced by high-fat diet and low dose of streptozotocin were randomly divided into sham and RYGB groups. The parameters of body weight, food intake, glucose tolerance, insulin sensitivity, and serum lipid profiles were assessed to evaluate metabolic changes. Intestinal sections were stained with hematoxylin and eosin (H&E) for light microscopy examination. The messenger RNA (mRNA) and protein expression levels of key regulatory enzymes of gluconeogenesis [phosphoenolpyruvate carboxykinase (PEPCK), glucose-6-phosphatase (G6Pase)] were determined through reverse-transcription PCR (RT-PCR) and Western blotting, respectively. Results: RYGB induced significant improvements in glucose tolerance and insulin sensitivity, along with weight loss and decreased food intake. RYGB also decreased serum triglyceride (TG) and free fatty acid (FFA) levels. The jejunum and ileum exhibited a marked increase in the length and number of intestinal villi after RYGB. The RYGB group exhibited downregulated mRNA and protein expression levels of PEPCK and G6Pase in the liver and upregulated expression of these enzymes in the jejunum and ileum tissues. Conclusions: RYGB ameliorates glucose and lipid metabolism accompanied by weight loss and calorie restriction. The small intestine shows hyperplasia and hypertrophy after RYGB. Meanwhile, our study demonstrated that the reduced hepatic gluconeogenesis and increased intestinal gluconeogenesis may contribute to improved glucose homeostasis after RYGB. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
36. Genome-wide association studies of drought-related metabolic changes in maize using an enlarged SNP panel.
- Author
-
Zhang, Xuehai, Warburton, Marilyn, Setter, Tim, Liu, Haijun, Xue, Yadong, Yang, Ning, Yan, Jianbing, and Xiao, Yingjie
- Subjects
EFFECT of drought on corn ,CORN genetics ,SINGLE nucleotide polymorphisms ,CORN metabolism ,ABIOTIC stress ,PLANT development - Abstract
Key message: Genetic determinants of metabolites related to drought tolerance in maize. Abstract: Water deficit or drought is one of the most serious abiotic stresses of plant development and greatly reduces crop production, and the plant's response to this deficit leads to many metabolic changes. To dissect the genetic basis of these metabolic traits in maize, we performed a genome-wide association analysis of drought-related traits using 156,599 SNPs in 318 maize inbred lines. In total, 123 significant SNP/trait associations ( P ≤ 6.39E−6) involving 63 loci were identified for related metabolic and physiological traits in multiple tissues and different environments under two irrigation conditions. Of the 63, 23 loci demonstrated a significant interaction effect between QTL and water status, indicating that these metabolite-associated loci were probably related to drought stress tolerance. To evaluate the potential utility of metabolite-associated loci applied in hybrid maize breeding, we assembled two groups of hybrid entries with high or low drought tolerance and measured the metabolic and physiological traits. In the hybrid pools, a set of 10 metabolite-associated loci identified in leaf and ear were validated as responsive to drought stress. The favorable alleles of these ten loci were significantly enriched in hybrids with high drought tolerance, which jointly explained almost 18.4 % of the variation in drought tolerance using a multivariate logistic regression model. These results provide clues to understanding the genetic basis of metabolic and physiological changes related to drought tolerance, potentially facilitating the genetic improvement of varieties with high drought tolerance in maize breeding programs. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
37. The expression of β-galactosidase during long-term cultured goat skin fibroblasts and the effect of donor cell passage on in vitro development of nuclear transfer embryos.
- Author
-
Liu, Haijun, Peng, Hui, Liu, Fang, Ma, Qun, and Zhang, Wenchang
- Abstract
The present study aimed to detect the expression of β-galactosidase during long-term cultured goat skin fibroblasts and investigate the effects of donor goat age, sex, and cell passage on senescence and the effects of donor cell passage on in vitro development of nuclear transfer embryos. The results showed that, in the same cell passage, more β-galactosidase-positive cells were detected in cells from older donors than younger donors. Irrespective of the donor age, the number of positive cells was higher in later passages from passages 20 to 50. In the same passage from 20 to 50, the β-galactosidase-positive rate was higher in cells from 5-yr female goat than 5-yr male goat. Using fibroblasts from male goats at various passages as donor cells, reconstructed embryos had similar fusion and cleavage rates, but the blastocyst rate was higher for cells at passages 10 and 20 than passage 30. In conclusion, donor goat age and cell passage had significant effects on the β-galactosidase-positive rate; also, cells from 5-yr female goat had a higher β-galactosidase-positive rate than those from 5-yr male goat, and the donor cell passage affected the developmental potential of nuclear transfer embryos. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
38. Nitrate nitrogen accumulation and leaching pattern at a winter wheat: summer maize cropping field in the North China Plain.
- Author
-
Li, Yan, Liu, Haijun, Huang, Guanhua, Zhang, Ruihao, and Yang, Huiying
- Subjects
WINTER wheat ,CROPPING systems ,NITRATE minerals ,NITROGEN content of plants ,SOIL quality ,GROUNDWATER quality - Abstract
Excess application of nitrogen has proved to be one of the detrimental impact factors on soil and groundwater quality in the North China Plain (NCP). A 4-year (from October 2008 to September 2012) field experiment was carried out to investigate the impact of N application rate on NO-N dynamics in soils, its leaching pattern, and movement in deep soils under different nitrogen (N) application rates in a sprinkler irrigated winter wheat ( Triticum aestivum L.)- summer maize ( Zea mays L.) field in the NCP. The N application rates were 0, 110, 220, and 330 kg N ha per wheat or maize planting season, referred to as CK, N1, N2, and N3 treatments, respectively. The results indicate that in winter wheat season, the applied water and fertilizer N mostly accumulated in the 0-60 cm soil layer and NO-N leaching out of the root zone (0-100 cm) was negligible under the sprinkler irrigation scheduling, while water and NO-N leached out of the root zone during summer maize season mainly due to high rainfall event. A relatively constant NO-N concentration in soil profile was maintained and NO-N leaching was negligible when N application rate was 110 kg N ha per crop season. While about 70 % of the applied N accumulated in 0-500 cm soil layer and about 50 % of the applied N leached out of the root zone when N application rate lager than 110 kg N ha per crop season, and the NO-N downward movement was observed to the depth of 300 cm at the end of the 4-year experiment with an average migration rate of about 50 cm year. Considering the potential risk of groundwater pollution, an N application rate of 110 kg ha per crop season was recommend for winter wheat and summer maize under the conditions of sprinkler irrigation in the NCP and those areas with similar conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
39. Multiple copies of the PsbQ protein in a cyanobacterial photosystem II assembly intermediate complex.
- Author
-
Liu, Haijun, Weisz, Daniel, and Pakrasi, Himadri
- Abstract
Photosystem II (PSII) undergoes frequent damage owing to the demanding electron transfer chemistry it performs. To sustain photosynthetic activity, damaged PSII undergoes a complex repair cycle consisting of many transient intermediate complexes. By purifying PSII from the cyanobacterium Synechocystis sp. PCC 6803 using a histidine-tag on the PsbQ protein, a lumenal extrinsic subunit, a novel PSII assembly intermediate was isolated in addition to the mature PSII complex. This new complex, which we refer to as PSII-Q4, contained four copies of the PsbQ protein per PSII monomer, instead of the expected one copy. In addition, PSII-Q4 lacked two other lumenal extrinsic proteins, PsbU and PsbV, which are present in the mature PSII complex. We suggest that PSII-Q4 is a late PSII assembly intermediate that is formed just before the binding of PsbU and PsbV, and we incorporate these results into an updated model of PSII assembly. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
40. A Novel Styryldehydropyridocolinium Homodimer: Synthesis and Fluorescence Properties Upon Interaction with DNA.
- Author
-
Yao, Huirong, Chang, Lifang, Liu, Chang, Jiao, Xiaojie, He, Song, Liu, Haijun, and Zeng, Xianshun
- Subjects
DNA ,PHOTOLUMINESCENCE ,FLUORESCENCE spectroscopy ,LUMINESCENCE spectroscopy ,FLUOROPHORES ,FLUORESCENCE ,FLUORIMETRY - Abstract
A novel homodimer of the styryldehydropyridocolinium dye ( TPTP) has been synthesized and characterized. Free TPTP exhibited low fluorescence quantum yield and large Stokes shift (over 160 nm) in water. However, it showed a significant fluorescence turn-on effect upon intercalation into DNA base pairs. Meanwhile, the fluorescence intensity of the intercalated structures formed by TPTP and DNA decreased quickly upon addition of deoxyribonuclease I, indicating that the dye can be used to monitor deoxyribonuclease I activity and DNA hydrolysis. Electrophoresis analysis revealed that the dye had intercalative binding to DNA and can potentially be used for DNA staining in electrophoresis. Thus, the innate nature of large Stokes shift and excellent fluorescence turn on effect upon interaction with DNA endue the dye with a wide range of applications. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
41. Human Action Recognition Using Maximum Temporal Inter-Class Dissimilarity.
- Author
-
Liu, Haijun and Li, Lan
- Published
- 2014
- Full Text
- View/download PDF
42. SAR Target Recognition via Sparsity Preserving Projections.
- Author
-
Li, Lan, Cheng, Jian, and Liu, Haijun
- Published
- 2014
- Full Text
- View/download PDF
43. Face Detection Based on Cost-Gentle Adaboost Algorithm.
- Author
-
Cheng, Jian, Liu, Haijun, Wang, Jian, and Li, Hongsheng
- Published
- 2014
- Full Text
- View/download PDF
44. A maize wall-associated kinase confers quantitative resistance to head smut.
- Author
-
Xu, Mingliang, Tan, Guoqing, Chen, Yongsheng, Liu, Haijun, Zuo, Weiliang, Ye, Jianrong, Zhao, Jing, Li, Bailin, Yan, Jianbing, Chao, Qing, Zhang, Nan, Zhang, Boqi, Zhao, Xianrong, Lai, Jinsheng, Xing, Yuexian, and Fengler, Kevin A
- Subjects
CORN disease & pest resistance genetics ,CORN disease & pest prevention ,KINASE genetics ,GENETIC engineering of corn ,CORN genetics ,CEREAL smut diseases ,FUNGAL diseases of plants ,PREVENTION - Abstract
Head smut is a systemic disease in maize caused by the soil-borne fungus Sporisorium reilianum that poses a grave threat to maize production worldwide. A major head smut quantitative resistance locus, qHSR1, has been detected on maize chromosome bin2.09. Here we report the map-based cloning of qHSR1 and the molecular mechanism of qHSR1-mediated resistance. Sequential fine mapping and transgenic complementation demonstrated that ZmWAK is the gene within qHSR1 conferring quantitative resistance to maize head smut. ZmWAK spans the plasma membrane, potentially serving as a receptor-like kinase to perceive and transduce extracellular signals. ZmWAK was highly expressed in the mesocotyl of seedlings where it arrested biotrophic growth of the endophytic S. reilianum. Impaired expression in the mesocotyl compromised ZmWAK-mediated resistance. Deletion of the ZmWAK locus appears to have occurred after domestication and spread among maize germplasm, and the ZmWAK kinase domain underwent functional constraints during maize evolution. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
45. Potential toxicity of amphenicol antibiotic: binding of chloramphenicol to human serum albumin.
- Author
-
Chen, Huilun, Rao, Honghao, He, Pengzhen, Qiao, Yongxiang, Wang, Fei, Liu, Haijun, Cai, Minmin, and Yao, Jun
- Subjects
CHLORAMPHENICOL ,SERUM albumin ,ANTIBIOTICS ,FOURIER transform infrared spectroscopy ,MOLECULAR docking - Abstract
Antibiotics are widely used in daily life but their abuse has posed a potential threat to human health. To evaluate the toxicity of chloramphenicol (CAP) at the protein level, the interaction between CAP and human serum albumin (HSA) was investigated by fluorescence, Ultraviolet-visible (UV-Vis) absorption, Fourier transform infrared (FT-IR) spectroscopy and molecular docking methods. Fluorescence data revealed that the fluorescence quenching of HSA by CAP was the result of the formation of CAP-HSA complex, and the binding constant was determined to be 3.196 × 10 L mol at 310 K. The thermodynamic determination indicated that the interaction was driven by enthalpy change and entropy change together, where the multiple hydrogen bonds (CAP and the residues Arg 222 and His 242 of HSA) and van der Waals forces were the dominant binding force. The site marker competition revealed that CAP bound into sub-domain IIA of HSA. The binding of CAP induced the drastic reduction in α-helix conformation and the significant enhancement in β-sheet conformation of HSA. Molecular docking study further confirmed the binding mode obtained by experimental study. This work provides a new quantitative evaluation method for antibiotics to cause the protein damage. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
46. High Accuracy Dynamic Adjusting Voltage Source for Cell Impedance Tomography Application.
- Author
-
Li, Nan, Xu, Hui, Yang, Yang, Diao, Jietao, Nie, Hongshan, Yu, Hongqi, and Liu, Haijun
- Published
- 2012
- Full Text
- View/download PDF
47. Precision Drip Irrigation on Hot Pepper in Arid Northwest China Area.
- Author
-
Yang, Huiying, Liu, Haijun, Li, Yan, Huang, Guanhua, and Wang, Fengxin
- Abstract
An experiment was conducted to study the effects of different soil water potential (SWP) on soil water content, hot pepper΄s yield, water consumption and water use efficiency (WUE) under plastic-mulched drip irrigation in the North-West China in order to find a suitable SWP to guide the pepper irrigation. Five treatments were set based on SWP, they are -10kPa (N1), -20kPa (N2), -30kPa (N3), -40kPa (N4) and -50kPa (N5). A control treatment (N6) was set based on local irrigation practice, i.e. border irrigation. SWP was measured using tensiometers at 0.2 m depth immediately under drip emitters. Pepper leaf area, plant height, soil water content, yield and total soluble solid (TSS) were measured, soil water content and water use efficiency were calculated. Results shows that the differences in leaf area index and plant height are not significant (P>0.05) among treatments of N1, N2, N3 and N4. While the pepper yields, WUE and TSS are higher for treatments N3 and N4. Controlling SWP at -50kPa greatly decreases crop yield and WUE. Therefore, we recommend -30 ~ -40 kPa as the irrigation threshold for pepper cultivation under mulched drip irrigation in arid areas of the North-West China. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
48. Excited state properties of chlorophyll f in organic solvents at ambient and cryogenic temperatures.
- Author
-
Niedzwiedzki, Dariusz, Liu, Haijun, Chen, Min, and Blankenship, Robert
- Abstract
Chlorophyll f is a photosynthetic pigment that was discovered in 2010. In this study, we present investigations on spectral and dynamic characteristics of singlet-excited and triplet states of Chl f with the application of ultrafast time-resolved absorption and fluorescence spectroscopies. The pigment was studied at room temperature in two organic solvents: pyridine and diethyl ether that have different characters of coordination of the chlorophyll magnesium (Mg) atom (hexa- and penta-coordination, respectively). Cryogenic measurements (77 K) were performed in 2-methyltetrahydrofuran (hexa-coordination). The singlet-excited state lifetime was measured to be 5.6 ns at room temperature regardless of Mg coordination and 8.1 ns at 77 K. The fluorescence quantum yield of Chl f was also determined in pyridine to be 0.16. The triplet state lifetime was studied in detail in pyridine at room temperature, and the inherent lifetime was estimated to ~150 μs. Selective measurements at 77 K demonstrated that the metastability of the triplet state greatly enhances, and its lifetime increases by a factor of more than three. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
49. Silhouette analysis for human action recognition based on maximum spatio-temporal dissimilarity embedding.
- Author
-
Cheng, Jian, Liu, Haijun, and Li, Hongsheng
- Subjects
- *
FACE perception , *HUMAN behavior , *EMBEDDED computer systems , *SPATIO-temporal variation , *INFORMATION theory , *HAUSDORFF spaces - Abstract
In this paper, we present a human action recognition method for human silhouette sequences. Inspired by the locality preserving projection and its variants, a novel manifold embedding method, maximum spatio-temporal dissimilarity embedding, is proposed to embed each action frame into a manifold, where frames from different action classes can be well separated. Unlike existing methods that incorporate both inter-class and intra-class information in the embedding process, our proposed method focuses on maximizing distances between frames that are similar in appearance but are from different classes and takes the temporal information into consideration. A variant of Hausdorff distance is introduced for frame and sequence classifications. Extensive experimental results and comparison with state-of-the-art methods demonstrate the effectiveness and robustness of the proposed method for human action silhouette analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
50. Quantitative estimation of climate change effects on potential evapotranspiration in Beijing during 1951-2010.
- Author
-
Liu, Haijun, Li, Yan, Josef, Tanny, Zhang, Ruihao, and Huang, Guanhua
- Abstract
Climate change is likely to affect hydrological cycle through precipitation, evapotranspiration, soil moisture etc. In the present study, an attempt has been made to study the climate change and the sensitivity of estimated evapotranspiration to each climatic variable for a semi-arid region of Beijing in North China using data set from 1951 to 2010. Penman-Monteith method was used to calculate reference crop evapotranspiration (ETo). Changes of ETo to each climatic variable was estimated using a sensitivity analysis method proposed in this study. Results show that in the past 60 years, mean temperature and vapor pressure deficit (VPD) were significantly increasing, relative humidity and sunshine hours were significantly decreasing, and wind speed greatly oscillated without a significant trend. Total precipitation was significantly decreasing in corn season (from June to September), but it was increasing in wheat season (from October to next May). The change rates of temperature, relative humidity, VPD, wind speed, annual total precipitation, sunshine hours and solar radiation were 0.42°C, 1.47%, 0.04 kPa, 0.05 m·s, 25.0 mm, 74.0 hours and 90.7 MJ·m per decade, respectively. In the past 60 years, yearly ETo was increasing with a rate of 19.5 mm per decade, and total ETos in wheat and corn seasons were increasing with rates of 13.1 and 5.3 mm per decade, respectively. Sensitivity analysis showed that mean air temperature was the first key factor for ETo change in the past 60 years, causing an annual total ETo increase of 7.4%, followed by relative humidity (5.5%) and sunshine hours (−3.1%); the less sensitivity factors were wind speed (0.7%), minimum temperature (−0.3%) and maximum temperature (−0.2%). A greater reduction of total ETo (12.3%) in the past 60 years was found in wheat season, mainly because of mean temperature (8.6%) and relative humidity (5.4%), as compared to a reduction of 6.0% in ETo during corn season due to sunshine hours (−6.9%), relative humidity (4.7%) and temperature (4.5%). Increasing precipitation in the wheat season will improve crop growth, while decreasing precipitation and increasing ETo in the corn season induces a great pressure for local government and farmers to use water more efficiently by widely adopting water-saving technologies in the future. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.