Search

Aims: Biocrusts are important living covers in ecologically fragile regions that intercept metals entering the soil and indicate heavy metal contamination. This study explored the potential of biocrusts as a novel approach for remediating heavy metal pollution in mining areas. We also investigated the capacity of biocrusts to enrich or degrade heavy metals in gold mine tailings and analyzed the migration, transformation mechanisms, and potential toxic effects of heavy metals in the underlying biocrusts. Methods: We used the BCR sequential extraction procedure to analyze the speciation of heavy metals in the underlying biocrust layer (moss crusts, mixed crusts (moss + algal), and algal crusts). The risk assessment code (RAC) and potential ecological risk index (Er) were used to evaluate the impact of biocrusts on the ecological risk assessment of heavy metals in soil. Results: The results showed that (1) well-developed biocrusts had a strong ability to enrich heavy metals, with these metals accumulating at the surface; (2) biocrust growth facilitated the conversion of heavy metals from an inert state to an active form in the underlying layer, enhancing their bioavailability; (3) Spearman's correlation and redundancy analysis (RDA) revealed the total amount of heavy metals as the primary factor driving the translocation of soil heavy metals, with soil pH, cationic exchange capacity (CEC) and organic matter content (SOM) exerting varying influences; (4) the comprehensive potential ecological risk index indicated that heavy metals in gold tailings at the strong risk levels, mainly due to arsenic exceeded the standard (~ 7 × background values). However, biocrusts reduced the Er of heavy metals in the underlying layer. The RAC results indicated low mobility and bioavailability of heavy metals in the underlying layer, associated with low ecological risk. Conclusions: As the 'skin' of soil, biocrusts could protect soil from heavy metal contamination. Despite enhancing heavy metal bioavailability, their enrichment effect was much greater than their activation effect. As a result, biocrusts hold great promise for remediating heavy metal pollution in degraded ecosystems. Further exploration of the influencing mechanism of biocrusts on heavy metals will help validate their use in mine restoration processes. [ABSTRACT FROM AUTHOR]

Cardiovascular disease (CVD) is a major threat to public health worldwide. The relationship between CVD and temperature has been widely reported in developed countries and regions. However, there are few studies of severe CVD in poor rural areas of developing countries. Therefore, this study aimed to explore the relationship between CVD and apparent temperature (AT) in a rural area of Linxia Hui Autonomous Prefecture, China. Daily CVD admission data and meteorological data were collected from Linxia between 2014 and 2015. The media of AT was used as the reference temperature to estimate the cumulative relative risk (RR) of CVD admission. The distributed lag non-linear models were used to examine the association between AT and cumulative RR of CVD admission at lag 0–21 days. In Linxia, high AT (20 °C) had a persistent adverse effect on cumulative RR of CVD admissions, and the RR increased with increasing lag days. Cold (− 10 °C) had a protective effect on the first and later lag days (lag 0–14 and lag 0–21). Adults (aged < 65 years) and females were more susceptible to the effects of heat than males and the elderly (aged ≥ 65 years). In Linxia, China, extremely high AT is an important risk factor for CVD hospitalizations in suburban and rural populations. [ABSTRACT FROM AUTHOR]

The effect of ambient temperature on relative risk (RR) of cardiovascular disease (CVD) is different in China than in other countries due to the different geographical environment, climate the different inter- and intra-individual characteristics of the population within China. It is therefore important to integrate information to evaluate the impact of temperature on RR of CVD in China. We performed a meta-analysis to evaluate the effect of temperature on RR of CVD. The Web of Science, Google Scholar, and China National Knowledge Infrastructure databases were searched back to 2022 and nine studies were included in the study. The Cochran Q test and I2 statistics were used to assess heterogeneity, while Egger's test was used to assess publication bias. The pooled estimated size of the relationship between ambient temperature and CVD hospitalization in the random effect model was 1.2044 (95%CI: 1.0610—1.3671) for the cold effect and 1.1982 (95%CI: 1.0166—1.4122) for the heat effect. The Egger's test showed a potential publication bias for the cold effect, whereas there was no apparent publication bias for the heat effect. There is a significant effect of ambient temperature on RR of CVD for both the cold effect and heat effect. The effect of socioeconomic factors should be considered more thoroughly in future studies. [ABSTRACT FROM AUTHOR]

Background: To retrospectively characterize the clinical characteristics and efficacy of total hip arthroplasty and the important factors needing attention in hypophosphatemic osteomalacia (HO) patients with hip involvement. Patients and methods: We performed a review of seven patients (two women and five men) referred to our clinic with a final diagnosis of HO who received total hip arthroplasty between 2010 and 2018. Five patients (Group 1) received proper medical management with or without aetiologic therapy, while the other two patients (Group 2) did not receive due to misdiagnosis. The mean follow-up duration was 5.1 ± 2.0 years. Results: The patients in Group 1 had significant relief of pain and improved laboratory results. The mean Harris Hip Score of Group 1 increased from 44.2 ± 6.0 to 94.0 ± 3.0, and the mean VAS score decreased from 8.8 ± 0.4 to 1.8 ± 0.7. However, the progressive extensive pain score in Group 2 had no obvious improvement, with the Harris Hip Score increasing from 45.5 ± 0.5 to 60 ± 28.0 and the VAS score decreasing from 9.0 ± 1.0 to 6.5 ± 2.5. Conclusion: THA appears to be an effective method for hip arthritis or joint deformities resulting from hypophosphatemic osteomalacia. A satisfactory outcome of the surgery depends on the early etiological identification, the treatment of hypophosphatemia, a careful operation, and the operative strategies, as well as proper medical treatment. [ABSTRACT FROM AUTHOR]

Broca's area is composed of the pars opercularis (PO) and the pars triangularis (PTR) of the inferior frontal gyrus; the anterior ascending ramus of the lateral sulcus (aals) separates the PO from the PTR, and the horizontal ascending ramus of the lateral sulcus (hals) separates the PTR from the pars orbitalis. The morphometry of these two sulci maybe has potential effects on the various functions of Broca's area. Exploring the morphological variations, hemispheric differences and sex differences of these two sulci contributed to a better localization of Broca's area. BrainVISA was used to reconstruct and parameterize these two sulci based on data from 3D MR images of 90 healthy right-handed subjects. The 3D anatomic morphologies of these two sulci were investigated using 4 sulcal parameters: average depth (AD), average width (AW), outer length (OL) and inner length (IL). The aals and hals could be identified in 98.89% and 98.33%, respectively, of the hemispheres evaluated. The morphological patterns of these two sulci were categorized into four typical types. There were no statistically significant interhemispheric or sex differences in the frequency of the morphological patterns. There was statistically significant interhemispheric difference in the IL of the aals. Significant sex differences were found in the AD and the IL of the aals and OL of the hals. Our results not only provide a structural basis for functional studies related to Broca's area but also are helpful in determining the precise position of Broca's area in neurosurgery. [ABSTRACT FROM AUTHOR]

Climate change is increasing the incidence of extreme weather events which have a significant impact on public health. Cardiovascular diseases (CVDs) are the number one cause of death globally (40%). Apparent temperature (AT) and diurnal temperature range (DTR) have been extensively used to evaluate the effects of temperature on cardiovascular disease (CVD). However, the relevant information is quite limited from analysis and comparison of effects and differing pathogenesis of DTR and AT on CVD especially in less-developed, rural areas of China. This is the first attempt to analyze different effects between AT and DTR on CVD using distributed lag nonlinear modeling (DLNM) in rural area. Data on CVD hospital admission in Qingyang (Northwest China) in 2014–2017 originated from the New Rural Cooperative Medical System (NRCMS) of Gansu Province, and meteorological variables were provided by the Meteorological Science Data Sharing Service. Both AT and DTR had significant nonlinear and delayed impacts on hospital admissions for CVD. DTR had a stronger and more persistent effect on CVD incidence than AT. Females were more affected by high AT and low DTR than were males, while males were more vulnerable to low AT and high DTR. Temperature effects were not significantly different between people above and below 65 years of age. These findings provide local public health authorities with reference concerning sensitive temperature indices for susceptible populations with a view to improve CVD preventive strategies in rural areas. [ABSTRACT FROM AUTHOR]

The construction of landscape water bodies can improve the residential environment of the city to meet the residential requirements of residents. However, the cost of constructing landscape water bodies is too high and difficult to build. Most of them are static or immobile water systems. In many cities nowadays, the water landscape has been polluted, and the water body is overflowing with eutrophication. Reasonably optimizing the combination of multiple aquatic plants has a better purification function for the entire water body than a single plant, but it is easy to ignore the ecosystem chain of aquatic plants in the research process. With the improvement of people's living standards, the requirements for landscapes are getting higher and higher, so ecological waterscape construction has emerged. The environment where the construction of ecological waterscape is best has ornamental value. After reasonable transformation, the purification effect was formed. Therefore, it has important value to strengthen the purification process of aquatic plants. [ABSTRACT FROM AUTHOR]

The introduction of the key non-oxidative glycolytic (NOG) pathway enzyme, phosphoketolases (PKTs), into heterologous hosts can improve the yield of a variety of acetyl CoA-derived products of interest. However, the low specific activity of existing PKTs compared with that of 6-phosphofructokinase (PFK), the key EMP pathway enzyme, largely limits their potential applications. To improve PKT activity, previous attempts have focused on increasing intracellular PKT concentration via the use of strong promoters. Herein, we report the establishment of a growth-coupled evolution strategy for the enrichment and selection of PKT mutants with improved specific activity in Corynebacterium glutamicum hosts with defective PFK. Five mutants from 9 Bifidobacterium adolescentis-source PKT (BA-PKT) mutant libraries were obtained. Site-directed mutagenesis analysis revealed 11 mutant sites which contributed to improved BA-PKT specific activity. Further structural analysis revealed that the mutant sites were located far away from the enzyme active site, which makes them almost unpredictable using a rational design approach. Mutant site recombination led to the construction of a novel mutant, PKTT2A/I6T/H260Y, with Vmax 29.77 ± 1.58 U/mg and Kcat/Km 0.32 ± 0.01 s−1/mM, which corresponds to 73.27 ± 3.25% and 80.16 ± 3.38% improvements, respectively, compared with the wildtype (Vmax; 17.17 ± 0.59 U/mg, Kcat/Km; 0.17 ± 0.01 s−1/mM). Expression of PKTT2A/I6T/H260 in C. glutamicum Z188 resulted in 16.67 ± 2.24% and 18.19 ± 0.53% improvement in l-glutamate titer and yield, respectively, compared with the wildtype BA-PKT. Our findings provide an efficient approach for improving the activity of PKTs. Furthermore, the novel mutants could serve as useful tools in improving the yield of l-glutamate and other acetyl CoA-associated products. [ABSTRACT FROM AUTHOR]

Objective: To enhance the thermostability and deregulate the hemin inhibition of 5-aminolevulinic acid (ALA) synthase from Rhodopseudomonas palustris (RP-ALAS) by a computer-aided rational design strategy.Results: Eighteen RP-ALAS single variants were rationally designed and screened by measuring their residual activities upon heating. Among them, H29R and H15K exhibited a 2.3 °C and 6.0 °C higher melting temperature than wild-type, respectively. A 6.7-fold and 10.3-fold increase in specific activity after 1 h incubation at 37 °C was obtained for H29R (2.0 U/mg) and H15K (3.1 U/mg) compared to wild-type (0.3 U/mg). Additionally, higher residual activities in the presence of hemin were obtained for H29R and H15K (e.g., 64% and 76% at 10 μM hemin vs. 27% for wild-type). The ALA titer was increased by 6% and 22% in fermentation using Corynebacterium glutamicum ATCC 13032 expressing H29R and H15K, respectively.Conclusion: H29R and H15K showed high thermostability, reduced hemin inhibition and slightly high activity, indicating that these two variants are good candidates for bioproduction of ALA. [ABSTRACT FROM AUTHOR]

α-Amylase was used as a heterologous model protein to investigate the effects of promoters, signal peptides and over-expression of an extra-cytoplasmic molecular chaperone, PrsA lipoprotein, on enhancing the secretion of α-amylase in Bacillus subtilis. Four promoters and six signal peptides were compared, successively, and the highest yield of α-amylase was achieved under the promotion mediated by P, a strong constitutive promoter, and secretion by SP, a signal peptide from B. subtilis. Moreover, under conditions of overexpressed PrsA lipoprotein, the secretion production and activity of α-amylase increased to 2.5-fold. The performance of the recombinant B. subtilis 1A751PL31 was evaluated with a fed-batch fermentation in a 7.5 l fermentor. Optimization of regulatory elements and over-expression of PrsA lipoprotein had a significant effect on enhancing the production of α-amylase in B. subtilis. [ABSTRACT FROM AUTHOR]

Inflammation and infection play an important role in the pathogenesis of many cancers. Toll-like receptors (TLRs) are a class of pattern recognition receptors that recognize conserved components of microbes and trigger the immune response against invading microorganisms. Toll-like receptor 9 (TLR9) recognizes non-methylated cytosine-phosphateguanosine (CpG) DNA sequences which are the surrogate for viral DNA. TLR9 may react to tumor development and progression during chronic inflammation that involves the tumor microenvironment. In order to study the role of TLR9 in cervical cancer, we analyzed the TLR9 expression in different types of HPV infection cervical cancer cells. Then we detected if CpG sequences influenced the TLR9 expression and the sensitivity to cisplatin (DDP) of these cervical cancer cells in vitro. The expression of TLR9 mRNA and protein in SiHa, Hela and C33A cells was detected by RT-PCR and Western blotting. Real-time PCR was used to examine the TLR9 expression changes induced by CpG. Chemosensitivity of the cervical cancer cells to cisplatin (DDP) was measured by MTT. It was observed that the expression of TLR9 mRNA and protein was increased gradually in SiHa (HPV16+), Hela (HPV18+) and C33A (HPV−) cells. Low doses of CpG increased the TLR9 expression only in C33A (HPV−) cells, but not in SiHa (HPV16+) and Hela (HPV18+) cells. Furthermore, low dose of CpG significantly increased the sensitivity of C33A (HPV−) cells, but not that of SiHa (HPV16+) and Hela (HPV18+) cells. These results indicated that TLR9 may serve as a protective agent in HPV negative cervical cancer cells. It was concluded that TLR9 could improve the sensitivity to DDP in HPV negative cervical cancer cells and might represent a potential therapeutic option in clinical practice. [ABSTRACT FROM AUTHOR]

The influences of concentration and modulus of sodium silicate solution and curing mode on the phase composition, microstructure and strength development in the geopolymers prepared using Class F fly ash were investigated. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and MAS NMR were utilized. Results show that the compressive strength increases as sodium silicate solution modulus increases, but when modulus exceeds 1.4, the compressive strength decreases, and it decreases markedly while the modulus is greater than 2.0. The compressive strength was improved by the increase of sodium silicate solution concentration. When the concentration is 32%, the compressive strength reaches the maximum, then it reduces as concentration increasing. Elevated temperature can increase the strength of samples that synthesized from sodium silicate solution with 32% concentration and modulus 1.2. Compared to the strength of the sample cured at 50 °C, the strength of the samples cured at 65 °C and 80 °C are higher at 1 d and 3 d, but the same at 7 d. At high temperature, prolonged curing time will decrease the strength. Long precuring at room temperature before application of heat is beneficial for strength development, and there is about 50% increase in strength of the samples cured at 1 d precuring and 2 d elevated temperature as compared to the strengths of the samples cured for 3 d at elevated temperatures or cured for 28 d at room temperature. The main product of reaction in the geopolymeric material is amorphous alkali aluminosilicate gel. [ABSTRACT FROM AUTHOR]

Directional samples were taken to study rock magnetism and palaeomagnetic records from the Dongsheng profile, which is 5 m thick and on the northwest edge of the Bose Basin. Mineralogy and rock magnetism of typical samples indicate that coarse granular titanomagnetite, and fine-grained hematite, superparamagnetic maghemite formed by pedogenesis are in the sediment, which has undergone many transformative processes during different stages of pedogenesis. Parallel samples were taken for thermal demagnetization (TH) (0 to 680°C) and alternating field (AF) demagnetization (0 to 80 mT) respectively. Experimental results of these two kinds of demagnetization illustrate that there are two or more magnetic components in the samples. Intensity of NRM decreases by almost 60% to 90% rapidly when the temperature ranges from 100°C to 350°C, with a steady magnetic component. It is impossible to analyze the magnetic components at high temperature because those fluctuate widely when the temperature is higher than 400°C. Steady magnetic components from 100°C to 350°C indicate that the remanence was mainly carried by fine-grained hematite formed by pedogenesis, reflecting a change in the geomagnetic field while the magnetite was being oxidized into hematite by chemical weathering after deposition. The formative age of the sediments cannot be obtained by magnetic methods in this profile. [ABSTRACT FROM AUTHOR]

Two hundred and eighty-one samples, collected from drilling core NS93-5 located in the Nansha area of the South China Sea, were used to study the magnetic characteristics of the sediments in the sea. Detailed rock magnetic results show that the magnetic minerals of the sediments were dominated by ferrimagnetic minerals such as magnetite, and a small contribution of hematite and maghematite also existed. The sediments recorded three negative values of remanence magnetic inclination at the depth: 191–206 cm, 232–248 cm, and 292–308 cm. The corresponding ages of these negative values were 65.87–68.7 ka B.P., 73.4–80.8 ka B.P. and 108.4–113.6 ka B.P., respectively, according to stratigraphy of oxygen isotope, 14C, and the age of a volcanic ash layer. The negative value during 108.4–113.6 ka B.P. may be the record of a Blake event in the sediments of the Nansha area. [ABSTRACT FROM AUTHOR]