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Wide field of view and polarization imaging capabilities are crucial for implementation of advanced imaging devices. However, there are still great challenges in the integration of such optical systems. Here, we report a bionic compound eye metasurface that can realize full Stokes polarization imaging in a wide field of view. The bionic compound eye metasurface consists of a bifocal metalens array in which every three bifocal metalenses form a subeye. The phase of the bifocal metalens is composed of gradient phase and hyperbolic phase. Numerical simulations show that the bifocal metalens can not only improve the focusing efficiency in the oblique light but also correct the aberration caused by the oblique incident light. And the field of view of the bionic compound eye metasurface can reach 120° × 120°. We fabricated a bionic compound eye metasurface which consists of three subeyes. Experiments show that the bionic compound eye metasurface can perform near diffraction-limited polarization focusing and imaging in a large field of view. The design method is generic and can be used to design metasurfaces with different materials and wavelengths. It has great potential in the field of robot polarization vision and polarization detection.

Lychee is an exotic tropical fruit with a distinct flavor. The genome of cultivar ‘Feizixiao’ was assembled into 15 pseudochromosomes, totaling ~470 Mb. High heterozygosity (2.27%) resulted in two complete haplotypic assemblies. A total of 13,517 allelic genes (42.4%) were differentially expressed in diverse tissues. Analyses of 72 resequenced lychee accessions revealed two independent domestication events. The extremely early maturing cultivars preferentially aligned to one haplotype were domesticated from a wild population in Yunnan, whereas the late-maturing cultivars that mapped mostly to the second haplotype were domesticated independently from a wild population in Hainan. Early maturing cultivars were probably developed in Guangdong via hybridization between extremely early maturing cultivar and late-maturing cultivar individuals. Variable deletions of a 3.7 kb region encompassed by a pair of CONSTANS-like genes probably regulate fruit maturation differences among lychee cultivars. These genomic resources provide insights into the natural history of lychee domestication and will accelerate the improvement of lychee and related crops., Two divergent haplotypes from a highly heterozygous lychee genome of the cultivar ‘Feizixiao’ and resequencing of 72 lychee accessions provide insights into the genome evolution and domestication history of lychee.

PurposeAccording to relational contract theory, relational governance has potential to improve public-private partnership (PPP) infrastructure project sustainability. The main purpose of this research is to investigate the association between relational governance and the sustainability of PPP infrastructure projects. Further, this study examines the mediating effect of managerial innovation and the moderating role of public involvement.Design/methodology/approachResearch data were collected from 158 valid questionnaires completed by Chinese PPP professionals. Structural equation modeling (SEM) was then employed to test five hypotheses.FindingsResults indicate a positive correlation between relational governance and PPP infrastructure project sustainability. This linkage is regulated by public involvement. In addition, managerial innovation plays a mediating role between relational governance and the sustainability of PPP infrastructure projects.Originality/valueThis study verifies the relationship between relational governance and PPP infrastructure project sustainability, as well as intermediary and regulatory factors, providing a new approach to achieving sustainability in PPP infrastructure projects.

PurposeThe risks and uncertainties of public–private partnership (PPP) projects threaten their sustainability. Contract flexibility, which is based on the theory of incomplete contract and transaction cost, may be a viable solution to this issue. The purpose of this study is to investigate the relationship between contract flexibility and the sustainability performance of PPP projects. The multiple mediating roles of justice perception and cooperation efficiency are assessed, thereby allowing the pathways and conditions to be understood more comprehensively for improving the sustainability performance of PPP projects.Design/methodology/approachNine hypotheses in the proposed research model are tested via structural equation modeling using data acquired from 218 Chinese PPP professionals.FindingsResults show that contract flexibility positively affects PPP project sustainability performance. Justice perception and cooperation efficiency play direct and sequential mediating roles in this effect.Originality/valueThis study validates that contract flexibility positively impacts the sustainability performance of PPP projects, where justice perception and cooperation efficiency serve direct and sequential mediating roles. The findings of this study contribute to an improved understanding of the effect of contract flexibility on the sustainability performance of PPP projects. Furthermore, they provide important theoretical and practical insights into contract management as well as beneficial information and valuable initiatives for improving the sustainability of PPP projects.

Clean energy transition has been considered as an indispensable way to attain sustainable development for China, where the coal-to-gas initiative plays a vital role towards the goal. This paper takes Beijing, China’s political and economic center as well as a national pioneer in the energy transition, as a case to systematically analyze the co-mitigation of air pollution (PM2.5) and carbon emissions (CO2) achieved by the policy-driven natural gas-coal consumption substitution. Firstly, a qualitative analysis of the relationship of Beijing’s coal-to-gas policies and its air quality has been conducted. Then, VAR and ARDL models are employed to quantitatively analyze the impacts of coal-to-gas policies on PM2.5 and CO2, respectively. Results show that (i) an innovation of natural gas/coal consumption ratio will reduce PM2.5 concentrations, and the effect decreases over time; and (ii) an increase of 1% in natural gas/coal consumption ratio in Beijing will cause a decrease of 0.0784% in CO2 emissions in the long run. Therefore, the coal-to-gas policies do increase the usage of natural gas and improve Beijing’s air quality. The assessment methods and conclusions can be regarded as a reference for not only China’s policymakers, but also other countries, especially nowadays when air quality is becoming more valued and GHGs are being tightly controlled.

Long-term efficacy of capecitabine plus oxaliplatin chemotherapy on stage III colon cancer: A meta-analysis

Futibatinib (FUT) is a potent inhibitor of fibroblast growth factor receptor (FGFR) 1-4 that is currently under clinical investigation for intrahepatic cholangiocarcinoma. Unlike its predecessors, FUT possesses an acrylamide warhead, which enables it to bind covalently to a free cysteine residue in the FGFR kinase domain. However, it remains uninterrogated if this electrophilic α

Insect compound eyes are optical systems with small volume and a compact structure. The ommatidia in the dorsal rim area of some insects have polarized vision, which can perceive the polarization pattern of the sky and provide them with navigation information. In this paper, inspired by the polarization-sensitive compound eyes of insects, a bio-inspired polarization navigation sensor based on artificial compound eyes is designed. The sensor consists of an artificial compound eye, an integrated polarization detector and an integrated circuit. The optical path of the sensor uses the lens defocus method, which can ensure that the sensor obtains redundant polarization information. The integrated polarization detector is used to obtain the polarization information of the incident light, and the integrated circuit is responsible for the calculation. To extract effective information from images, we propose a multi-threshold segmentation method to filter and classify effective pixels. We use the least squares method to fit the inherent error of the sensor and then compensate it. The indoor calibration accuracy of the sensor is ±0.3°, and the outdoor calibration accuracy is ±0.5°. The sensor can provide accurate direction information for general smart mobile devices. The size of the sensor is 4 × 4 × 2 cm, and the weight is only 15 g. The key components of the sensor can be mass-produced, and it is a miniaturized and low-cost polarization navigation sensor.

Background Litchi chinensis Sonn. is an economically important fruit tree in tropical and subtropical regions. However, litchi functional genomics is severely hindered due to its recalcitrance to regeneration and stable transformation. Agrobacterium rhizogenes-mediated hairy root transgenic system provide an alternative to study functional genomics in woody plants. However, the hairy root transgenic system has not been established in litchi. Results In this study, we report a rapid and highly efficient A. rhizogenes-mediated co-transformation system in L. chinensis using Green Fluorescent Protein (GFP) gene as a marker. Both leaf discs and stem segments of L. chinensis cv. ‘Fenhongguiwei’ seedlings were able to induce transgenic hairy roots. The optimal procedure involved the use of stem segments as explants, infection by A. rhizogenes strain MSU440 at optical density (OD600) of 0.7 for 10 min and co-cultivation for 3 days, with a co-transformation efficiency of 9.33%. Furthermore, the hairy root transgenic system was successfully used to validate the function of the key anthocyanin regulatory gene LcMYB1 in litchi. Over-expression of LcMYB1 produced red hairy roots, which accumulated higher contents of anthocyanins, proanthocyanins, and flavonols. Additionally, the genes involving in the flavonoid pathway were strongly activated in the red hairy roots. Conclusion We first established a rapid and efficient transformation system for the study of gene function in hairy roots of litchi using A. rhizogenes strain MSU440 by optimizing parameters. This hairy root transgenic system was effective for gene function analysis in litchi using the key anthocyanin regulator gene LcMYB1 as an example.

Background SWEETs (Sugar Will Eventually be Exported transporters) function as sugar efflux transporters that perform diverse physiological functions, including phloem loading, nectar secretion, seed filling, and pathogen nutrition. The SWEET gene family has been identified and characterized in a number of plant species, but little is known about in Litchi chinensis, which is an important evergreen fruit crop. Results In this study, 16 LcSWEET genes were identified and nominated according to its homologous genes in Arabidopsis and grapevine. Multiple sequence alignment showed that the 7 alpha-helical transmembrane domains (7-TMs) were basically conserved in LcSWEETs. The LcSWEETs were divided into four clades (Clade I to Clade IV) by phylogenetic tree analysis. A total of 8 predicted motifs were detected in the litchi LcSWEET genes. The 16 LcSWEET genes were unevenly distributed in 9 chromosomes and there was one pairs of segmental duplicated events by synteny analysis. The expression patterns of the 16 LcSWEET genes showed higher expression levels in reproductive organs. The temporal and spatial expression patterns of LcSWEET2a and LcSWEET3b indicated they play central roles during early seed development. Conclusions The litchi genome contained 16 SWEET genes, and most of the genes were expressed in different tissues. Gene expression suggested that LcSWEETs played important roles in the growth and development of litchi fruits. Genes that regulate early seed development were preliminarily identified. This work provides a comprehensive understanding of the SWEET gene family in litchi, laying a strong foundation for further functional studies of LcSWEET genes and improvement of litchi fruits.

In thermal-storage photovoltaic-concentrated solar power (PV-CSP) systems, the fluctuant part electricity is stored in thermal energy storage (TES) system instead of high-cost batteries. In this research, PV nominal power, system power output point and TES capacity in different dispatch strategies are optimized by GA-PSO to achieve a minimized levelized cost of electricity. Then, more power output points are set in each strategy, operating performance and optimal configuration in these complex strategies are studied. After that, optimal configurations and operating characteristics in different heliostats and PV panels cost are explored, and the battery bank is considered. Results show that for the selected CSP subsystem in constant-output strategy, in which CSP power responds to PV power output to provide a constant system power curve, the optimal PV nominal power is 35.23 MW, system power output point is at the CSP-rated power and LCOE is 16.93 ¢/kWh. For independent-output strategy, in which CSP and PV provide power independently, optimal PV nominal power is 213.91 MW, PV power output point is 76.10 MW and LCOE is 16.33 ¢/kWh. For constant-output strategy with one (50% load) or three (75%, 50%, 25% load) middle power output points settled, the optimal systems based on these complex strategies can reach a lower LCOE of 15.32 ¢/kWh and 15.15 ¢/kWh, respectively. In independent-output strategy, LCOE of optimal systems based on complex strategies is 14.33 ¢/kWh and 12.80 ¢/kWh, respectively. In general, the operating performance are more superior and steadier for CON strategy and a large-scale PV subsystem is needed for IND strategy in most conditions.

Many experimental results have revealed that the re‐entanglement kinetics of disentangled polymers is much slower than that predicted by tube theory. This retarded recovery of fully entangled state is of practical significance that shear‐induced modification may offer a way to improve processability for a polymer by reducing viscosity. This work tried to figure out the shear‐rate dependence variation of viscosity in the view of evolution of entanglement state through disentanglement and re‐entanglement, aiming to provide fundamental insights into application prospect of shear‐induced modification in preparing “in‐pellet” disentangled polymers prior to final processing. High‐density polyethylene was sheared on a parallel‐plate rotational rheometer with a linearly increased shear rate. Results showed that higher shear rate could induce further disentanglement, resulting in a lower viscosity with a reduction rate up to 93.7%, larger molecular weight between entanglements Mₑ, and longer re‐entanglement time. Additionally, less entanglement would give a larger lamellar thickness of sheared samples after nonisothermal crystallization. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 598–606

Three novel fluorescent probes (L1, L2 and L3) derived from 2-hydroxyphenyl-4-chloromethyloxazole 8-ydroxyquinaldine were designed and synthesized. The probes showed highly selectively and sensitivity towards Cu2+ ion through “turn off” response in DMF/H2O solution (v/v = 1/1, 0.01 M, Tris-HCl buffer, pH 7.30). The detection limits of probes were up to 8.24 × 10−8 M for Cu2+ ion, which were much lower than drinking water permission concentrations by the United States Environmental Protection Agency. Sequentially, the L1-Cu2+, L2-Cu2+ and L3-Cu2+ complexes detected citrate anion (CA) through “turn on” response. The probes, were also found to be reversible and recyclable toward Cu2+ ion and CA controlled “On–Off–On” fluorescent switch and acted as molecular logic gates. Furthermore, the in vivo sensitivity experiments of Cu2+ ion and CA were demonstrated through fluorescence imaging in living cells.

Hydrogels based on nanocomposites (NC) structure have acquired a great deal of interest, but they are still limited by relatively low mechanical strength, inevitably losing elasticity when applied below subzero temperatures, due to the formation of ice crystallization. In this study, an anti-freezing and mechanically strong Laponite NC organohydrogel was prepared by a direct solvent replacement strategy of immersing Laponite NC pre-hydrogel into ethylene glycol (EG)/water mixture solution. In the organohydrogel, a part of water molecules was replaced by EG, which inhibited the formation of ice crystallization even at extremely low temperatures. In addition, the formation of hydrogen bonds between Laponite and the monomers of N-isopropylacrylamide (NIPAM) and hydroxyethyl acrylate (HEA) endowed the organohydrogels with high mechanical strength and toughness. The NC organohydrogel can maintain its mechanical flexibility even at −25 °C. The compressive stress, tensile stress, and elongation at the break of N5H5L reached 3871.71 kPa, 137.05 kPa, and 173.39%, respectively, which may be potentially applied as ocean probes in low temperature environment.

The pathogenic fungus Neoscytalidium dimidiatum (Nd) is the causal agent of pitaya canker and causes significant yield losses. The mechanism by which Nd invades pitaya stems remains largely unknown. Here, quantitative proteomic analysis was employed to investigate pitaya immune responses against Nd infection. A total of 2766 proteins including 244 differentially expressed proteins (DEPs) were identified during infection. Nearly half of the upregulated proteins were predicted to be located in the chloroplast and mitochondrion, implying that these organelles are most affected by fungal infection. Bioinformatics analysis indicated that the DEPs were associated with photosynthesis, phytohormone activity, reactive oxygen species (ROS) homeostasis, and pathogenic defense responses. Notably, the phytohormones auxin and abscisic acid were accumulated for defense against Nd invasion. qRT-PCR validation showed that the mRNA expression levels of auxin binding protein (ABP), auxin response 4 protein (ARP4), and aspartic protease 2 (ASP2) were not consistent with the protein variation, suggesting that these proteins were regulated post-transcriptionally. Additionally, DEPs associated with ROS metabolism changed markedly, indicating that ROS homeostasis in pitaya is important for defense against Nd invasion. In summary, the results revealed the involvement of many essential proteins in the response to Nd infection and provide a basis for studying other biotic stresses of pitaya.

In response to climate change and energy transition, natural gas has been rapidly developed as a relatively low-carbon energy source by many countries. However, there remain environmental risks at different stages in the entire process from exploitation to utilization. Firstly, this article identifies various environmental risks and benefits of natural gas along the entire industry chain from upstream exploitation and midstream transportation to downstream utilization. It is found that, during upstream exploitation, hydraulic fracturing has the worst environmental impact. During the midstream storage and transportation stage, methane leakage is the biggest environmental risk. In the downstream combustion and utilization stage, the risk to environment is less than other energy sources, although there are some greenhouse gas effects and water pollution issues. Thus, this article puts forward some policy recommendations for different stages from exploitation to utilization. In the upstream stage, especially hydraulic fracturing activity, we suggest strengthening environmental assessment management, improving policy standards, creating a water quality monitoring plan, and promoting the innovation of key technologies. In terms of the midstream, besides pipeline laying and site selection, we focus on monitoring the system, including leak detection, quality management of engineering materials, and risk identification and management. When it comes to the downstream, we encourage the application of advanced technologies to improve thermal efficiency and reduce emissions, such as gas-fired related technologies, natural gas recycling technologies, distributed energy technologies, and green and low-carbon service technologies.

Lhermitte-Duclos disease (LDD) is a type of rare brain tumor located in posterior fossa. A patient with LDD located in the left cerebellum and vermis was admitted by the Department of Neurosurgery, Xiangya Hospital, Central South University. MRI scan showed slightly heterogeneous enhancement at the region close to vermis. The patient underwent partial resection on August 11, 2016 without postoperative chemoradiotherapy. The progress free survival was 11 months and the overall survival was 17 months. What the case reveals is that the partial resection is not beneficial to these patients with LDD as the residual lesion probably recurs in a short term after operation. The pathogenesis, diagnosis and treatment of LDD are explored and summarized in combination with relevant literature.小脑发育不良性神经节细胞瘤(Lhermitte-Duclos disease，LDD)是一种罕见的位于后颅窝的脑部肿瘤。中南大学湘雅医院神经外科收治了1例起源于左侧小脑和蚓部的LDD患者，MRI显示肿瘤在近蚓部区域呈轻度不均匀强化，在2016年8月11日进行肿瘤部分切除后未进行放射治疗和化学治疗。无进展生存时间为11个月，总体生存时间为17个月，说明部分切除不利于患者预后，因为残留的病灶可能会在短期内出现复发。本文还结合相关文献，对LDD的发病原因和诊治方法进行了探讨。.

Clean energy transition has been considered as an indispensable way to attain sustainable development for China, where the coal-to-gas initiative plays a vital role towards the goal. This paper takes Beijing, China's political and economic center as well as a national pioneer in the energy transition, as a case to systematically analyze the co-mitigation of air pollution (PM

The objective of this study, a digital in vivo anatomical study based on patient-specific three-dimensional (3D) models reconstructed from computed tomography (CT) scans, was to clarify the anatomy of the presacral space and suggest a safe area for complication-free graft or mesh fixation. We retrospectively studied 182 CT angiography (CTA) datasets from Han Chinese women examined for gynecological diseases from January 2018–June 2020; we used Mimics 21.0 to create 176 3D models of the female presacral space. The distances of pelvic structures from the presacral vessels and ureters were standardized and measured in 3D mode. The distances from the median sacral artery (MSA) to the bilateral great vessels and bilateral ureters at the sacral promontory (SP) level were similar to the respective distances from the midpoint of the SP (MSP) to those four structures (p > 0.05). At the level of the first transverse line, when the MSA was right of the midline, the MSA was 20.74 ± 3.86 mm from the medial edge of the left first anterior sacral foramen. When the MSA was left of the midline, its average distance from the medial edge of the right first anterior sacral foramen was 20.89 ± 4.92 mm. The SP was 9.71 ± 4.49 mm and 40.39 ± 6.74 mm, respectively, from the first and second sacral transverse veins along the midline. To preserve important vasculature, we recommend a 30 × 20-mm (L × W) avascular rectangular-shaped area, 10 mm below the SP and alongside the MSA, for safe graft or mesh attachment during sacrocolpopexy.

Longan (Dimocarpus longan) is a typical southern subtropical fruit tree species that is sensitive to cold stress. C-repeat binding factors (CBFs), as transcription factors, are crucial components involved in the molecular regulation of the plant response to cold stress. However, the role of CBF homologs in the cold response regulation of longan remains largely unknown. Here, three novel CBF genes, DlCBF1, DlCBF2, and DlCBF3, were cloned from longan. DlCBF1 and DlCBF2 contain an AP2 domain and PKKPAGR and DSAWR CBF signature motifs, while DlCBF3 has mutations within these conserved signature motifs. DlCBF1/2/3 were mainly localized in the nucleus and specifically bound to CRT/DRE cis-elements, resulting in strong transcriptional activation. DlCBF1/2 exhibited tissue expression specificity, and their expression was induced by low temperature, while DlCBF3 had no tissue specificity and barely responded to low temperature. DlCBF1, DlCBF2, and DlCBF3 overexpression in Arabidopsis-enhanced cold tolerance by increasing proline accumulation and reducing reactive oxygen species (ROS) content, accompanied by upregulated expression of cold-responsive genes (AtRD29A, AtCOR15A, AtCOR47, and AtKIN1) in the CBF cold stress response signaling pathway. In conclusion, the biological functions of DlCBF1/2/3 were somewhat conserved, but slow expression of DlCBF1/2 and low expression of DlCBF3 may partly cause the cold sensitivity of longan. Collectively, these results indicated that differences exist in the expression and function of CBF orthologs in the cold-sensitive plant species longan, and these findings may help to improve the understanding of the cold response regulation mechanism and provide important theoretical support for cold-tolerant breeding of longan.

A novel Schiff base fluorescence probe (HL) was synthesized by the condensation of salicylaldehyde and an 8-aminoquinoline derivative. This probe acts as a “turn-on” dual selectivity fluorescence probe for Zn2+ and Al3+ ions, providing different colors and detection limits (DL) of 11.5 and 23.5 nM, respectively. Moreover, when Zn2+ and Al3+ co-exist, HL exhibits a preference for Al3+ by displacing Zn2+ from the HL-Zn2+ complex, realizing a dual-channel signal output for Al3+. The HL-Al3+ system could further discern F− by a “turn-off” fluorescence response with a DL of 86.0 nM. Furthermore, the probe HL was capable of monitoring intracellular Al3+, Zn2+ and F− in living PC12 cells in vitro through fluorescence imaging, which proved its value in potential in vivo applications.

A novel fluorescent probe 2-(2'-hydroxyphenyl)-4-(phenylethylamino)methyloxazole (HPO) has been synthesized, which performed highly selective and sensitive detection of Zn2+ ion with a discriminating enhancement over the other metal ions. The binding constant was calculated as 3.07 × 103 M-1 with detection limit of 1.22 × 10-6 M in aqueous solution (CH3CN-Tris v/v, 1/1, Tris, 10 mM, pH = 7.4). Moreover, the HPO-Zn2+ complex could serve as an excellent tartrate anion (TA). The detection mode maybe due to TA detach Zn2+ ion from HPO-Zn2+ complex leading to resulting in the release of the free probe HPO. As a result, a logic circuit has also been constructed on the basis of Zn2+ and TA as chemical inputs. Furthermore, fluorescence imaging experiments showed that probe HPO could be used as an effective fluorescent probe for detecting Zn2+ and TA in living cells.

We have developed a novel quinoline-derived Schiff base fluorescent Cu2+ ion probe fluorescent probe 2-(2-hydroxybenzylidene)hydrazono)methyl)- quinolin-8-ol (QH). The probe QH showed a highly selective and sensitive detection of Cu2+ with significant fluorescence “turn-on” response and the solution color changed from colorless to yellowish green. The results of fluorescence titration, Job's plot and HRMS analysis suggested that the stoichiometry of probe QH and Cu2+ was found to be 1:1. The detection limit was found to be 8.08×10−9 M, which far lower than the maximum allowable level of the U.S. Environmental Protection Agency limit (20 μM) for drinking water. The bonding mechanism has been discussed according to FT-IR and DFT calculations. Furthermore, probe QH has been successfully applied to living cell imaging.

Four novel fluorescence sensors bearing a quinolylbenzothiazole platform were synthesized and characterized. The sensors displayed excellent selectivity and highly sensitive fluorescence response to Fe3+ ion in H2O/DMSO buffer solution (1:4 volume ratio; Tris-HCl, 0.01 mol/L; pH = 7.40) at 500 nm originating from quinolylbenzothiazole fluorophore group. Other cations, namely Li+, Na+, K+, Mg2+, Ca2+, Co2+, Ni2+, Cd2+, Cu2+, Zn2+, Mn2+, Ba2+, Pb2+, Hg2+, Al3+, and Eu3+, showed no appreciable change in fluorescence spectrum. The binding stoichiometry between sensors L1, L2, L3, or L4 and Fe3+ was observed to be 1:1 based on fluorescence titration and Jobs plot analysis. The detection limits of L1, L2, L3, and L4 for Fe3+ were found to be 0.155, 0.362, 0.249, and 0.517 μmol/L, respectively. Furthermore, possible utilization of sensors to detect Fe3+ in living HeLa cells was also investigated by confocal fluorescence microscopy.

The α-, β-, and γ-polymorphs of polypropylene random copolymer with two kinds of β-nucleating agent (TMB-5 and WBG-2) have been studied via wide-angle X-ray diffraction and differential scanning calorimetry. It was found that the addition of 0.5 wt% β-nucleating agent (β-NA) hardly induces appreciable β-modification content, until β-NA content is up to 1 wt%. It seems that low amount of β-NA is not enough to counterbalance the nucleation ability and high content of defects (stereo- and regioerrors) of co-PP, and only α- and γ-modifications are obtained in the samples. Moreover, the relative amount of γ-crystal depends on the crystallization temperature. Although TMB-5 has better heterogeneous nucleation effect than WBG-2, the ability to form stable β-polymorph of WBG-2 is stronger than that of TMB-5. Since large amount of β-nucleation sites overcome the defects of co-PP molecular chain and curb the formation of γ-crystal, competitive growth of α- and β-polymorphs ultimately leads to the coexistence of α- and β-modification.

Two novel acridine-based fluorescence chemosensors (L1 and L2) were prepared and their metal ions sensing properties were investigated. L1 (L2) exhibited an excellent selective fluorescence response toward Fe3+ (Ni2+) and the stoichiometry ratio of L1-Fe3+ and L2-Ni2+ were 1:1. The detection limits of L1 and L2 were calculated by the fluorescence titration to be 4.13 μM and 1.52 μM, respectively, which were below the maximum permissive level of Fe3+ and Ni2+ ions in drinking water set by the EPA. The possible mechanism of the fluorescence detection of Fe3+ and Ni2+ had been proposed according to the analysis of Job's plot, IR spectra and ESI-MS. The determination of Fe3+ and Ni2+ ions in living cells had been applied successfully.

Novel phenanthroline Schiff base fluorescent sensors L1, L2, and D1 were designed and synthesized. The sensing abilities of the compounds in the presence of metal cations (Li+ , Na+ , K+ , Ag+ , Mg2+ , Ba2+ , Ca2+ , Mn2+ , Pb2+ , Hg2+ , Ni2+ , Zn2+ , Cd2+ , Co2+ , Cu2+ , Cr3+ , Fe3+ , Fe2+ , Al3+ , and Eu3+ ) were studied by UV-vis and fluorescent spectroscopy. The compounds L1, L2, and D1 could act as Eu3+ ion turn-off fluorescent sensors based on ligand-to-metal binding mechanism in DMSO-H2 O solution (v/v = 1:1, 10 mM Tris, pH = 7.4). Additionally, the L1-Eu3+ and D1-Eu3+ complexes could be applied as turn-on enantioselective sensors sensing of malate anion isomers with color changes. Furthermore, biological experiments using living PC-12 cells demonstrated that L1 and D1 had excellent membrane permeability and could be used as effective fluorescent sensors for detecting Eu3+ and malate anion in living cells.