Phase-Controllable Growth of Air-Stable SnS Nanostructures for High-Performance Photodetectors with Ultralow Dark Current

The epitaxial growth of low-dimensional tin chalcogenides SnX (X = S, Se) with a controlled crystal phase is of particular interest since it can be utilized to tune optoelectronic properties and exploit potential applications. However, it still remains a great challenge to synthesize SnX nanostructures with the same composition but different crystal phases and morphologies. Herein, we report a phase-controlled growth of SnS nanostructures via physical vapor deposition on mica substrates. The phase transition from α-SnS (Pbnm) nanosheets to β-SnS (Cmcm) nanowires can be tailored by the reduction of growth temperature and precursor concentration, which originates from a delicate competition between SnS-mica interfacial coupling and phase cohesive energy. The phase transition from the α to β phase not only greatly improves the ambient stability of SnS nanostructures but also leads to the band gap reduction from 1.03 to 0.93 eV, which is responsible for fabricated β-SnS devices with an ultralow dark current of 21 pA at 1 V, an ultrafast response speed of ≤14 μs, and broadband spectra response from the visible to near-infrared range under ambient condition. A maximum detectivity of the β-SnS photodetector arrives at 2.01 × 108 Jones, which is about 1 or 2 orders of magnitude larger than that of α-SnS devices. This work provides a new strategy for the phase-controlled growth of SnX nanomaterials for the development of highly stable and high-performance optoelectronic devices.

Space-confined growth of large-mismatch CsPb(BrxCI1−x)3/GaN heterostructures with tunable band alignments and optical properties

Space-confined growth strategy is developed to grow large-mismatch CsPb(Br1−xClx)3/GaN heterostructures with type-II band alignment and tunable optical properties'.

[Application of multi-stage competing risk model to survival data]

The traditional proportional hazard model is commonly used to investigate the association between main outcome and predictor variables. However, the endpoints in medical studies are often not unique. The analyses of labeling other competing outcomes other than the main outcome as censored data will theoretically lead to a biased estimate of the risk of main outcome. Although the traditional competitive risk model can adjust the influence of other outcomes on the risk of the main outcome, it can not directly compare the differences on the risks of different outcomes. The multi-state competing risk model provides a relatively suitable solution for this problem. In this study, based on a previously published follow-up data set for prostate cancer patients, we developed traditional proportional hazard model, traditional competitive risk model, and multi-state competing risk model, respectively. By comparing the advantages and disadvantages of the three models with the same survival data, we clarified the clinical application value of the multi-state competitive risk model in survival data with multiple outcomes.

[Potential pleiotropism of cancer-related single nucleotide polymorphisms among Chinese population]

Objective: To investigate the potential pleiotropism of cancer-related single nucleotide polymorphisms (SNPs) among Chinese population. Methods: Based on the catalogue of GWAS jointly constructed by the National Human Genome Research Institute and the European Institute of Bioinformatics, according to population origin (Chinese population and non-Chinese population) and disease traits (cancer and non-cancer traits). All SNPs found by GWAS before August 2020 were divided into four categories: cancer in Chinese population, non-cancer in Chinese population, cancer in non-Chinese population and non-cancer in non-Chinese population. The number, correlation and linkage of the four categories of SNPs were described. Results: By August 2020, a total of 196 813 SNPs from 4 096 GWAS were included in the GWAS directory. The information that SNPs refer to unknown or were not related to the disease was excluded, and 117 441 independent SNPs were finally included. There were 619 SNPs related to cancer and 9 569 SNPs related to non-cancer disease in Chinese population, respectively. There were 4 624 SNPs related to cancer and 106 448 SNPs related to non-cancer disease (trait) in non-Chinese population, respectively. Three SNPs, rs2736100, rs6983267 and rs401681, were associated with two or more types of cancer in both Chinese and non-Chinese populations. Seven SNPs, rs7705526, rs2736100, rs10993994, rs2735839, rs4430796, rs174537 and rs9271588, were associated with cancer and non-cancer diseases in both Chinese and non-Chinese populations, respectively. Conclusion: There is a potential pleiotropism of cancer-related SNPs in Chinese population.

Comparing the bone mineral density among male patients with latent autoimmune diabetes and classical type 1 and type 2 diabetes, and exploring risk factors for osteoporosis

AIMS

This study aimed to compare the bone mineral densities (BMDs) among male patients with latent autoimmune diabetes in adults (LADA), classical type 1 diabetes (T1DM), and type 2 diabetes (T2DM), and to examine the risk factors for developing low BMD in these patients.

PATIENTS AND METHODS

Between January 2017 and October 2020, a total of 57, 67, and 223 male patients with LADA, classical T1DM, and T2DM, respectively, were recruited from the endocrinology department of Shanghai Tenth People's Hospital. Hormonal markers of bone metabolism, lipid profiles, uric acid, glycosylated hemoglobin A1c (HbA1c), and beta-cell function were measured using blood samples. BMD was measured at the lumbar spine, femoral neck, and right hip by dual-energy X-ray absorptiometry.

RESULTS

The mean BMD values from all three skeletal sites in male patients with LADA were comparable to those with classical T1DM but were much lower than those with T2DM. After adjusting for confounding factors, multiple linear regression analysis demonstrated that in all male patients with diabetes, body mass index (BMI), uric acid, and fasting C-peptide showed significant positive associations with BMD at all three skeletal sites; however, osteocalcin showed a negative association at all three sites.

CONCLUSIONS

Compared with male patients with T2DM, lower BMDs were observed in patients with LADA and T1DM. Low BMI, uric acid, C-peptide levels, and high osteocalcin levels are risk factors for developing low BMD in male patients with diabetes.

Study on the clinical application of the MRS in the cognitive assessment after stroke

OBJECTIVE

To discuss the value of the application of the magnetic resonance spectroscopy (MRS) in the assessment of cognitive function impairment and the observation of therapeutic effect.

PATIENTS AND METHODS

30 patients with cognitive impairment after stroke (cognitive impairment group) and 30 patients with no apparent cognitive impairment (control group of the stroke) were selected through the screening of the mini-mental state examination (MMSE) scale, and another 30 healthy volunteers were selected (control group of the health). The general information of gender, age, education degree, disease duration and so on was matched among the 3 groups. MRS examined all the patients of the 3 groups at the time of enrollment, and the patients of both cognitive impairment and control groups received another assessment 2 months after treatment.

RESULTS

The NAA/Cr (N-acetyl aspartate/creatine) of the bilateral hippocampus of the cognitive impairment group was lower than those of both control group of stroke and health (p < 0.05), while the Cho/Cr was higher (p < 0.05). After treatment, both patients of the cognitive impairment group and the control group of the stroke experienced an increase of NAA/Cr and a decrease of Cho/Cr (p < 0.05).

CONCLUSIONS

MRS is applicative in the assessment of the cognitive impairment degree of the stroke patients and can also effectively identify the existence of the cognitive impairment, which makes it preferably valuable in the clinical application.

Refractive index sensor based on the leaky radiation of a microfiber

In this work we present a refractive index sensor based on the leaky radiation of a microfiber. The 5.3um diameter microfiber is fabricated by drawing a commercial optical fiber. When the microfiber is immersed into a liquid with larger refractive index than the effective index of fiber mode, the light will leak out through the leaky radiation process. The variation of refractive index of liquid can be monitored by measuring radiation angle of light. The refractive index sensitivity can be over 400 degree/RIU in theory. In the experiment, the variation value 0.001 of refractive index of liquid around this microfiber can be detected through this technique. This work provides a simple and sensitive method for refractive index sensing application.

Transformation bending device emulated by graded-index waveguide

We demonstrate that a transformation device can be emulated using a gradient-index waveguide. The effective index of the waveguide is spatially varied by tailoring a gradient thickness dielectric waveguide. Based on this technology, we demonstrate a transformation device guiding visible light around a sharp corner, with low scattering loss and reflection loss. The experimental results are in good agreement with the numerical results.

Simple way for achieving passive all-optical switching of continuous waves lasers using pure nematic liquid crystal

We have examined pure nematic liquid crystal (LC), 4'-pentyl-4-biphenylcarbonitrile (5-CB), with a 90° twisted alignment within a cell made of two cross-polarized absorptive plastic polarizers, and investigated the nonlinear transmission properties using cw (532 nm) lasers. We observed optically self-activated polarization switching with a factor of three lower switching power than a dye-doped LC cell with similar linear transmittance using glass substrates. We also studied the dynamics of the switching processes and observed millisecond switching time. These studies have demonstrated a simpler but more efficient way for fabricating broadband, low switching power, millisecond time scale switching, and optical limiting devices.

New lead structures in antifungal drug discovery

During the past two decades, the incidence of invasive fungal infections has been increasing dramatically. Clinical available antifungal agents have several drawbacks such as limited potency and spectrum, drug related toxicity, non-optimal pharmacokinetics, and severe resistance. There is an emergent need to develop new antifungal drugs with novel chemical structures and novel mechanism of action. This review will focus on the most significant achievements in the discovery of antifungal lead structures within last few years. In particular, we pay more attention on the structure-activity relationship of antifungal leads and provide perspectives for future antifungal drug discovery.

Homology Modeling of Lanosterol 14α-Demethylase ofCandida albicansandAspergillus fumigatusand Insights into the Enzyme-Substrate Interactions

The crystal structure of 14alpha-sterol demethylase from Mycobacterium tuberculosis (MT_14DM) provides a good template for modeling the three dimensional structure of lanosterol 14alpha-demethylase, which is the target of azole antifungal agents. Homologous 3D models of lanosterol 14alpha-demethylase from Candida albicans (CA_14DM) and Aspergillus fumigatus (AF_14DM) were built on the basis of the crystal coordinates of MT_14DM in complex with 4-phenylimidazole and fluconazole. The reliability of the two models was assessed by Ramachandran plots, Profile-3D analysis, and by analyzing the consistency of the two models with the experimental data on the P450(14DM). The overall structures of the resulting CA_14DM model and AF_14DM model are similar to those of the template structures. The two models remain the core structure characteristic for cytochrome P450s and most of the insertions and deletions expose the molecular surface. The structurally and functionally important residues such as the heme binding residues, the residues lining the substrate access channel, and residues in active site were identified from the model. To explore the binding mode of the substrate with the two models, 24(28)-methylene-24,25-dihydrolanosterol was docked into the active site of the two models and hydrophobic interaction and hydrogen-bonding were found to play an important role in substrate recognition and orientation. These results provided a basis for experiments to probe structure-function relationships in the P450(14DM). Although CA_14DM and AF_14DM shared similar core structural character, the active site of the two models were quite different, thus allowing the rational design of specific inhibitors to the target enzyme and the discovery of novel antifungal agents with broad spectrum.

Direct nitric oxide imaging in cultured hippocampal neurons with diaminoanthraquinone and confocal microscopy

A method for the direct measurement of intracellular nitric oxide (NO) production stimulated by penicillin G (PG) in cultured hippocampal neurons with diaminoanthraquinone (DAA) using laser scanning confocal microscopy (LSCM) was developed. Intracellular DAA fluorescence could specifically represent NO production based on two facts: (1) 3-morpholinosydnonimine, a NO donor, could dose-dependently increase DAA fluorescence; and (2) haemoglobin, a NO scavenger, could inhibit the increase of DAA fluorescence. The PG dose-dependently increased the intercellular level of glutamate (Glu, 5 min after stimulation) and the intracellular NO production (30 min throughout stimulation). The increase of NO production could be reversed by N(w)-nitro- l -arginine (a NO synthase inhibitor), and also by d (-)2-amino-5-phosphonovaleric acid, a subtype of Glu receptor antagonist. These results revealed that DAA could be used to indicate real-time and kinetic intracellular NO production of hippocampal neurons with higher sensitivity, specificity and accuracy.

Synthetic fuel for imitation of municipal solid waste in experimental studies of waste incineration

Synthetic fuel is prepared to imitate municipal solid waste (MSW) in experimental studies of incineration processes. The fuel is composed based on the Environmental Protection Agency reports on the materials contained in MSW. Uniform synthetic fuel pellets are prepared using available and inexpensive components including newsprint, hardwood mulch, low density polyethylene, iron, animal feed, sand, and water to imitate paperbound, wood, yard trimming, plastic, metal, food wastes, and other materials in MSW. The synthetic fuel preparation procedure enables one to reproduce and modify the fuel for a wide range of experiments in which the mechanisms of waste incineration are addressed. The fuel is characterized using standard ASTM tests and it is shown that its parameters, such as combustion enthalpy, density, as well as moisture, ash and fixed carbon contents are adequate for the representation of municipal solid waste. In addition, chlorine, nitrogen, and sulfur contents of the fuel are shown to be similar to those of MSW. Experiments are conducted in which the synthetic fuel is used for operation of a pilot-scale incinerator research facility. Steady-state temperature operation regimes are achieved and reproduced in these experiments. Thermodynamic equilibrium flame conditions are computed using an isentropic one-dimensional equilibrium code for a wide range of fuel/air ratios. The molecular species used to represent the fuel composition included cellulose, water, iron, polyethylene, methanamine, and silica. The predicted concentrations of carbon monoxide, nitric oxides, and oxygen in the combustion products are compared with the respective experimental concentrations in the pilot-scale incinerator exhaust.

Influence of neutral cyclodextrin concentration on plate numbers in capillary electrophoresis

A quantitative theory of plate number N in capillary electrophoresis was developed for buffers containing neutral cyclodextrins (CDs) capable of forming inclusion complexes. In the theory, N was modeled by longitudinal diffusion, injection extent, width of the detection window, and the detector time constant. The apparent mobility was modeled as a weighted sum of the mobilities of the free-solution analyte and the inclusion complex. The apparent diffusion coefficient was modeled as a similarly weighted sum. Both the apparent mobility and diffusion coefficient were corrected by functions that compensated for increases of buffer temperature caused by Joule heat. The experimental N's and apparent mobilities of neutral thiourea and of the anions, dansyl D- and L-leucine, dansyl D- and L-aspartic acid, benzoate, and 4-nitrophenolate, were determined in buffers containing from 0 to 15 mM beta-CD. The binding constants, and mobilities and diffusion coefficients of the free-solution analyte and inclusion complex, were calculated as regression coefficients by fitting theory to these determinations. The regression coefficients were shown to have physicochemical meaning, as assessed by literature values, independent measurements, and theoretical predictions. The assessment showed the Nernst-Einstein equation does not relate mobilities and diffusion coefficients at the electrolyte concentration used. The interdependence of mobilities, diffusion coefficients, binding constants, and other dispersion sources was interpreted to evaluate the factors affecting the variation of N with CD concentration. From the interpretation, an approximate equation for N in low-concentration CD buffers was derived. The equation depends on free-solution and inclusion-complex mobilities and diffusion coefficients, the binding constant, the potential difference over the effective capillary length, and the number of plates in a CD-free buffer.

Baseline blink rates and the effect of visual task difficulty and position of gaze

PURPOSE

To compare the baseline blink rates (BBR) measured under different (baseline) conditions, and to compare the blink rates measured when performing two visual tasks of different levels of difficulty at two positions of gaze.

METHODS

In the first single masked experiment, BBR were measured under three different conditions - (i) conversation with the subjects (ii) taking the visual acuity and (iii) keeping the subjects waiting in an empty examination room. In the second single masked experiment, the subjects were required to perform an easy task (reading normal English words) and a difficult task (reading mirror-image English words) at primary gaze and down gaze. The orders of the tasks performed were randomly allocated.

RESULTS

BBR taken under the three different conditions were significantly different from each other. No significant difference was found between the blink rates measured when performing the two reading tasks if they were performed at the same position of gaze. The mean blink rates were significantly lower when performing the tasks at down gaze than when performing the tasks at primary gaze. No significant differences were found between BBR-waiting and blink rate measured when the subject was doing the easy task at primary gaze, and between BBR-VA and blink rate measured when the subject was performing the difficult task at primary gaze.

CONCLUSIONS

BBR measured under different (baseline) conditions produced different results so it is important for investigators to describe the baseline condition very clearly in studies where BBR are measured. Our results also indicated that mean blink rate was affected by the position of gaze and not the level of task difficulty.

[Separation of dicarboxylic acid by thin-layer chromatography]

Dicarboxylic acids (C2-C6) were detected on thin-layer chromatography of silica gel G after developing with V(benzene):V(acetic acid):V(water) = 50:40:10 for an hour by dipping the plate in a very short time. The chromogenic reagent was 0.1% bromocresol green alcohol solution adjusted to pH 7. The acid appeared as yellow spots on a blue background.

Embryo-specific gene expression in microspore-derived embryos of brassica napus. An interaction between abscisic acid and jasmonic acid1,2

The induction of napin and oleosin gene expression in Brassica napus microspore-derived embryos (MDEs) was studied to assess the possible interaction between abscisic acid (ABA) and jasmonic acid (JA). Napin and oleosin transcripts were detected sooner following treatment with ABA than JA. Treatment of MDEs with ABA plus JA gave an additive accumulation of both napin and oleosin mRNA, the absolute amount being dependent on the concentration of each hormone. Endogenous ABA levels were reduced by 10-fold after treatment with JA, negating the possibility that the observed additive interaction was due to JA-induced ABA biosynthesis. Also, JA did not significantly increase the uptake of [3H-ABA] from the medium into MDEs. This suggests that the additive interaction was not due to an enhanced carrier-mediated ABA uptake by JA. Finally, when JA was added to MDEs that had been treated with the ABA biosynthesis inhibitor fluridone, napin mRNA did not increase. Based on these results with the MDE system, it is possible that embryos of B. napus use endogenous JA to modulate ABA effects on expression of both napin and oleosin. In addition, JA could play a causal role in the reduction of ABA that occurs during late stages of seed development.

Immunohistochemical distribution of oestrogen receptor and luteinizing hormone B subunit in the ovine pituitary gland during foetal development

The presence of oestrogen receptor in the developing hypothalamo-hypophyseal system is an essential prerequisite for the development of sex-steroid feedback on gonadotrophin secretion. We have used dual immunocytochemistry to examine the ontogeny and regional distribution of oestrogen receptor and LHbeta subunit in the ovine pituitary gland during foetal development. At day 65 gestation (term= 145 days) oestrogen receptor and LH/ immunopositive cells are found in a small region at the base of the anterior pituitary gland, and also in a band immediately adjacent to the neurointermediate lobe. By day 100 gestation there was a significant increase in the number of immunopositive LHbeta cells accounting for around 12% of the total cell population, and these were widely distributed throughout the anterior pituitary gland. There was also a significant increase in the proportion of gonadotrophs which contain oestrogen receptor compared with day 65. By day 130 gestation the percentage of LH containing cells had declined to around 7% of the total population, but the proportion which also contained oestrogen receptor remained the same. There were no differences in the numbers or distribution of cells containing LH or oestrogen receptors between male and female foetuses, at any age. These data describing a parallel change in the number of oestrogen receptors and LHbeta containing cells in the pituitary gland throughout gestation suggest that the development of pituitary sex-steroid feedback is not solely dependent on changes in the numbers of oestrogen receptor containing cells alone.

Shoot versus Root Signal Involvement in Nodulation and Vegetative Growth in Wild-Type and Hypernodulating Soybean Genotypes

Grafting studies involving Williams 82 (normally nodulating) and NOD1-3 (hypernodulating) soybean (Glycine max [L.] Merr.) lines and Lablab purpureus were used to evaluate the effect of shoot and root on nodulation control and plant growth. A single- or double-wedge graft technique, with superimposed partial defoliation, was used to separate signal control from a photosynthate supply effect. Grafting of hypernodulated soybean shoots to roots of Williams 82 or L. purpureus resulted in increased nodule numbers. Grafting of two shoots to one root enhanced root growth in both soybean genotypes, whereas the nodule number was a function of shoot genotype but not of the photosynthetic area. In double-shoot, single-root-grafted plants, removing trifoliolate leaves from either Williams 82 or NOD1-3 shoots decreased root and shoot dry matter, attributable to decreased photosynthetic source. Concurrently, Williams 82 shoot defoliation increased the nodule number, whereas NOD1-3 shoot defoliation decreased the nodule number on both soybean and L. purpureus roots. It was concluded that (a) soybean leaves are the dominant site of autoregulatory signal production, which controls the nodule number; (b) soybean and L. purpureus have a common, translocatable, autoregulatory control signal; (c) seedling vegetative growth and nodule number are independently controlled; and (d) two signals, inhibitor and promoter, may be involved in controlling legume nodule numbers.

Identification of three C20-gibberellins: GA97 (2 beta-hydroxy-GA53), GA98 (2 beta-hydroxy-GA44) and GA99 (2 beta-hydroxy-GA19)

Three new C20-gibberellins, GA97 (2 beta-hydroxy-GA53), GA98 (2 beta-hydroxy-GA44) and GA99 (2 beta-hydroxy-GA19), have all been isolated from spinach, GA97 also from tomato root cultures and pea pods, and GA98 from maize pollen. The structures of these compounds were established by GC-mass spectrometric comparisons of the trimethylsilylated methyl esters with authentic samples prepared from gibberellic acid (GA3).

[Effects of different lowdoses of aspirin on platelet activation and the number of platelets in the patients with coronary heart disease]

The number of alpha-granule membrane protein 140 (GMP-140) molecules was detected by using specific monoclonal antibodies (125I-SZ-51) against GMP-140 in three groups of patients with unstable angina treated with aspirin 50 mg (n = 27), 150 mg (n = 26) and 300 mg (n = 30) a day before and 7 days after treatment. The number of platelets was counted by using the routine method. The results indicated that the number of GMP-140 molecules decreased significantly and the number of platelets increased significantly after treatment with aspirin. With the increase of aspirin dosage the degree of these two changes increased (P < 0.01, both) too. When 300 mg of aspirin was used, the number of GMP-140 molecules was lower than that in a control group of healthy subjects (P < 0.005) and the number of platelets reached that of the control group (P > 0.05). There was no difference on the immediate side effects when these three dosages of aspirin were used. The authors of the opinion are that it is rational to use 300 mg of aspirin to treat patients with unstable angina at the beginning.

Rhizobium leguminosarum as a plant growth-promoting rhizobacterium: direct growth promotion of canola and lettuce

Early seedling root growth of the nonlegumes canola (Brassica campestris cv. Tobin, Brassica napus cv. Westar) and lettuce (Lactuca sativa cv. Grand Rapids) was significantly promoted by inoculation of seeds with certain strains of Rhizobium leguminosarum, including nitrogen- and nonnitrogen-fixing derivatives under gnotobiotic conditions. The growth-promotive effect appears to be direct, with possible involvement of the plant growth regulators indole-3-acetic acid and cytokinin. Auxotrophic Rhizobium mutants requiring tryptophan or adenosine (precursors for indole-3-acetic acid and demonstrate a new facet of the Rhizobium-plant relationship and that Rhizobium leguminosarum can be considered a plant growth-promoting rhizobacterium (PGPR).

Computational simulation of blood flow in human systemic circulation incorporating an external force field

A quasi-one-dimensional non-linear mathematical model for the computation of the blood flow in the human systemic circulation is constructed. The morphology and physical modelling of the whole system (arteries, capillaries and veins) are completed by different methods for the different vessel generations. A hybrid method is used to solve the problem numerically, based on the governing equation (continuity, momentum and state equations), the input boundary conditions and the predetermined initial conditions. The two-step Lax-Wendroff finite-difference method is used to compute variables for each individual vessel, and the characteristic method is employed for the computation of internal boundary conditions of the vessel connection and the input and output system boundary conditions. Using this approach, blood flow, transmural pressure and blood velocity are computed at all vessel sites and for each time step. The pressure and flow waveforms obtained show reasonable agreement with clinical data and results reported in the literature. When an external conservative force field is applied to the system, the results computed from the model are intuitively correct. The term representing the external pressure added to the system by the muscle, which represents active control on the cardiovascular system, is also embodied in this model.