Squaramide-catalyzed enantioselective Michael addition of nitromethane to 2-enoylazaarenes: synthesis of chiral azaarene-containing γ-nitroketones.

Bifunctional chiral squaramide-catalyzed highly enantioselective Michael addition of nitromethane to diverse 2-enoylazaarenes was successfully performed. This protocol provided a set of chiral azaarene-containing γ-nitroketones with up to 98% yield and 98% ee in a solvent-free catalytic system under mild conditions. Furthermore, gram-scale synthetic utility was also showcased.

Interleukin-17 prevents oxidative stress from damaging osteoblast formation by inhibiting autophagic degradation of metallothionein-2.

Interleukin 17A (IL-17A) is a key cytokine promoting osteoblast formation, which contributes to osteogenesis. IL-17A functions in autophagy inhibition within osteoblasts. Metallothionein-2 (MT-2), as an important reactive oxygen species (ROS)-scavenging molecule, prevents oxidative stress from damaging osteoblast formation. The relationship between IL-17A-regulated autophagy and MT-2 production under oxidative stress deserves further exploration. In this study, we first investigated the roles of IL-17A in osteoblastic differentiation and ROS production in osteoblast precursors in the presence of hydrogen peroxide (H2O2). Next, we explored the effects of IL-17A on autophagic activity and MT-2 protein expression in osteoblast precursors in the presence of H2O2. Ultimately, by using autophagic pharmacological agonist (rapamycin) and lentiviral transduction technology, the relationship between autophagy, IL-17A-regulated MT-2 protein expression and IL-17A-regulated ROS production was further elucidated. Our results showed that in the presence of H2O2, IL-17A promoted osteoblastic differentiation and inhibited ROS production. Moreover, in the presence of H2O2, IL-17A inhibited autophagic activity and promoted MT-2 protein expression in osteoblast precursors. Importantly, IL-17A-promoted MT-2 protein levels and -inhibited ROS production were reversed by autophagy activation with rapamycin. Furthermore, IL-17A-inhibited ROS production were blocked by MT-2 silencing. In conclusion, IL-17A promotes ROS clearance by inhibiting autophagic degradation of MT-2, thereby protecting osteoblast formation from oxidative stress.

Regulation of NF-κB signaling by NLRC (NLRC3-like) gene in the common carp (Cyprinus carpio).

Among teleost NLRs, NLR-C subfamily is a large group of proteins that were teleost-specific and evolution analysis showed that NLR-Cs are most likely to evolve from NLRC3 gene (thus also called as NLRC3Ls). Presently, although there have been rich studies investigating teleost NLRC3 and NLRC3L, the data on the regulatory mechanism was limited. In this study, immune regulation of inflammatory signaling pathway mediated by common carp NLRC3L gene (CcNLRC) has been investigated. Confocal microscopy analysis showed that CcNLRC was located in cytoplasm, and in HEK293T cells, dual-luciferase reporter assay showed the regulation of NF-κB signaling by CcNLRC, in which CcNLRC could alter/decrease RIPK2-induced activation of NF-κB. These results indicated that CcNLRC may function as a negative NLR in the regulation of inflammatory response in common carp. Our data will allow to gain more insights into the molecular mechanism of teleost specific NLR (NLRC3L).

Enterocytozoon hepatopenaei (EHP) Infection Alters the Metabolic Processes and Induces Oxidative Stress in Penaeus vannamei.

Enterocytozoon hepatopenaei (EHP) is highly contagious and can cause hepatopancreatic microsporidiosis (HPM), which is typically characterized by the slow growth of shrimp. In this study, the differences in histology, metabolism, oxidative stress and growth between healthy and EHP-infected Penaeus vannamei were analyzed using an EHP challenge experiment. Histology showed that EHP caused lesions in the hepatic tubules of P. vannamei, such as hepatic tubular atrophy and epithelial cell shedding, with mature spores. Meanwhile, white feces may appear when the infection is severe. Furthermore, the content of total protein, glycogen, ATP and glucose in the EHP challenge group was significantly reduced. The qPCR results showed that EHP infection changed the expression of key genes in glucose metabolism, among which hexokinase (HK), phosphofructokinase (PFK), pyruvatekinase (PK), citrate synthase (CS) and isocitric dehydrogenase (IDH) were significantly down-regulated, while phosphoenolpyruvate carboxykinase (PEPCK), fructose bisphosphatase (FBP) and glucose-6-phosphatase (G6P) were significantly up-regulated. Obviously, the expression of growth-related genes was disordered. Simultaneously, the antioxidant genes manganese superoxide dismutase (MnSOD), catalase (CAT), glutathione peroxidase (GPX), glutathione-S-transferases (GST) and nuclear factor E2-related factor2 (Nrf2) were up-regulated to varying degrees in the EHP challenge group, and EHP infection induced significant increases in the oxidative damage products lipid peroxide (LPO) and malondialdehyde (MDA). Ultimately, the shrimp weight of the challenge group was 6.85 ± 0.86 g, which was significantly lower than that of the control group (8.95 ± 0.75 g). Taken together, we speculate that EHP changes the substance metabolism and growth process by causing oxidative damage to the hepatopancreas, which may lead to the growth retardation of P. vannamei.

Contributory roles of sarcopenia and myosteatosis in development of overt hepatic encephalopathy and mortality after transjugular intrahepatic portosystemic shunt.

BACKGROUND: Skeletal muscle abnormalities, such as muscle mass depletion (sarcopenia) and fatty infiltration of the muscle (myosteatosis), are frequent complications in cirrhotic patients scheduled for transjugular intrahepatic portosystemic shunt (TIPS). AIM: To investigate the association and predictive value of sarcopenia and myosteatosis for overt hepatic encephalopathy (HE) and mortality after TIPS. METHODS: The records of cirrhotic patients who underwent the TIPS procedure at our hospital between January 2020 and June 2021 were retrospectively retrieved. The transversal psoas muscle thickness (TPMT) and psoas muscle attenuation (PMA) measured from the unenhanced abdominal computed tomography (CT) at the level of the third lumbar vertebrae were used to analyze the sarcopenia and myosteatosis, respectively. The area under curve (AUC) was used to evaluate the discriminative power of TPMT, PMA, and relevant clinical parameters. Fur-thermore, log-rank test was performed to compare the incidence of overt HE and survival between the different groups, and the association of risk factors with overt HE and mortality was analyzed using Cox proportional hazards regression models. RESULTS: A total of 108 patients were collected. Among these patients, 45.4% of patients developed overt HE after TIPS treatment. Furthermore, 32.4% and 28.7% of these patients were identified to have myosteatosis and sarcopenia, respectively. Myosteatosis (51.0% vs 16.9%, P < 0.001) and sarcopenia (40.8 vs 18.6%, P = 0.011) were found to be more frequent in patients with overt HE, when compared to patients without overt HE. The receiver operating characteristics analysis indicated that the predictive power of TPMT and PMA in overt HE (AUC = 0.713 and 0.778, respectively) was higher when compared to the neutrophil lymphocyte ratio (AUC = 0.636). The cumulative incidence of overt HE was the highest in patients with concomitant sarcopenia and myosteatosis, followed by patients with myosteatosis or sarcopenia, while this was the lowest in patients without sarcopenia and myosteatosis. In addition, sarcopenia and myosteatosis were inde-pendently associated with overt HE and mortality after adjusting for confounding factors in post-TIPS patients. CONCLUSION: CT-based estimations for sarcopenia and myosteatosis can be used as reliable predictors for the risk of developing overt HE and mortality in cirrhotic patients after TIPS.

Designing incentive mechanism in contract farming considering reciprocity preference.

Contract farming is a growing practice in agricultural economy. A well-designed crop-planting and buyout contract, offered by an enterprise, to a fraction of contract farmers brings benefit to farmers as well as to the enterprise itself. However, in the process of contract fulfillment, farmers possess private information about the degree of effort on fulfilling the contract of themselves. Thus, the more informed farmers may not work hard in the process of planting crops. This opportunistic behavior of farmers caused by asymmetric information has seriously affected the sustainability of contract farming. An enterprise with reciprocity preference tends to make a contract both improves farmers' welfare and brings enough profit to sustain its own operations, while a farmer with reciprocity will work hard in return for the enterprise's reward. In this paper, we develop a non-profit index principal-agent model between enterprises and farmers, assuming both have reciprocity preference, to investigate how to design an incentive mechanism in contract farming. We begin our analysis by establishing a non-profit index evaluation system to evaluate farmers' effort degree in contract fulfillment. Then we solve principal-agent problem with the assumption that farmers' expected certainty income premium (ECIP) is constant. We find that in the perfect Bayesian equilibrium, farmers with higher degree of reciprocity preference require less ECIP, and will improve efforts to complete contract tasks, even actively sacrifice their own interests to repay extra rewards from enterprises. Furthermore, we explore our model to the scenario in which farmers' ECIP is a function of enterprise payment difference (EPD). We find that the higher the degree of reciprocity preference of farmers, the greater the probability of enterprises to increase income. Numerical simulations are conducted to verify the validity of the conclusions. Our study shows that the reciprocity preference behavior of enterprises and farmers improves the fulfillment rate of contract farming, which contributes to the realization of the incentive mechanism of contract farming.

[A rare case of dicentric ring chromosome and derivative ring chromosome Chimera].

OBJECTIVE: Utilize high-resolution chromosome analysis and microarray detection to determine the genetic etiology of infertility of a 32-year old female patient. METHODS: The peripheral blood of the patient was cultured for high-resolution chromosome G and C banding karyotype analysis, and then 750K SNP-Array chip detection was performed. RESULTS: Karyotype analysis results showed that the patient's karyotype was 45,XX,-13 [7]/46,XX,r(13) (p13q34) [185]/46,XX,dic r(13;13)(p13q34;p13q34) [14]/ 47,XX,+der(13;13;13;13) (p13q34;p13q34;p13q34; p13q34), dic r(13;13) [1]/ 46,XX [3]. The microarray results showed that the patient had a 3.3 Mb deletion in the 13q34 segment of chromosome 13, which may be related to infertility. CONCLUSION: Infertility of the patient reported in this article may be related to the deletion of chromosome segment (13q34-qter).

The effects of vacancy and oxidation on black phosphorus nanoresonators.

Black phosphorene (BP) is not stable at ambient conditions, so atomic defects and oxidation effects are unavoidable in BP samples in the experiment. The effects of these defects on the performance of the BP nanoresonators are still unclear. Here, we perform classical molecular dynamics to investigate the effects of the vacancy and oxidation on single-layer BP nanoresonators at different temperatures. We find that the vacancy causes a strong reduction in the quality factor of the nanoresonators, while the oxidation has a weaker effect on the nanoresonators. More specifically, a 2% concentration of randomly distributed single vacancies is able to reduce the quality factor by about 80% and 40% at 4.2 K and 50 K, respectively. We also find that the quality factor of the nanoresonators is not sensitive to the distribution pattern of the vacancy defects.

Thermal conductivity of graphene nanoribbons under shear deformation: A molecular dynamics simulation.

Tensile strain and compress strain can greatly affect the thermal conductivity of graphene nanoribbons (GNRs). However, the effect of GNRs under shear strain, which is also one of the main strain effect, has not been studied systematically yet. In this work, we employ reverse nonequilibrium molecular dynamics (RNEMD) to the systematical study of the thermal conductivity of GNRs (with model size of 4 nm × 15 nm) under the shear strain. Our studies show that the thermal conductivity of GNRs is not sensitive to the shear strain, and the thermal conductivity decreases only 12-16% before the pristine structure is broken. Furthermore, the phonon frequency and the change of the micro-structure of GNRs, such as band angel and bond length, are analyzed to explore the tendency of thermal conductivity. The results show that the main influence of shear strain is on the in-plane phonon density of states (PDOS), whose G band (higher frequency peaks) moved to the low frequency, thus the thermal conductivity is decreased. The unique thermal properties of GNRs under shear strains suggest their great potentials for graphene nanodevices and great potentials in the thermal managements and thermoelectric applications.

Effect of phacoemulsification on ocular surface and corneal endothelial cells in cataract patients with diabetes mellitus / 国际眼科杂志(Guoji Yanke Zazhi)

·AIM:To study the effects of phacoemulsification on ocular surface and corneal endothelial cells in cataract patients with diabetes mellitus.·METHODS:This study used a retrospective analysis of the clinical data to compare curative effect, the research object was 98 cases ( 98 eyes ) of cataract patients with phacoemulsification from January 2016 to December 2016 in our hospital. Patients were divided into the observation group and the control group according to whether diabetes merged. The observation group had 50 cases of cataract patients with diabetes, the control group had 48 cases of pure cataract patients. Two groups of patients underwent phacoemulsification surgery and transparent corneal incision, surgeries were completed by the same doctor, no xeroma before surgery. Preoperative glycemic control was normal for diabetic patients, no changes in eye fundus. Observation of ocular surface at postoperative 1, 3, 7d and 1mo was taken. Dry eye symptoms, lacrimal film breakup time ( BUT ) , corneal fluorescein staining ( FL ) score, SchirmerⅠtest ( SⅠt ) and corneal endothelial cell density were compared.·RESULTS: Dry eye symptom score of the two groups before and after operation had significant difference;data of the observation group at postoperative 7d and 1mo was significantly higher than that of the control group, there was statistical significance (P<0. 05), there was no significant difference at 1 and 3d after operation (P>0. 05 ). BUT of the two groups before and after surgery showed significant difference; data of the observation group at 7d and 1mo after operation was significantly lower than that of the control group, there was statistical significance ( P<0. 05 ); at 1 and 3d after operation there was no significant difference (P>0. 05). The FL score of the two groups before and after surgery had significant difference, and at 3, 7d and 1mo after operation, data of the observation group was significantly higher than that of the control group, there was statistical significance ( P< 0. 05 ); there was no significant difference at postoperative 1d (P>0. 05). The two groups' before and after surgery SⅠt had significant difference, at 1, 3, 7d and 1mo after operation, data of the observation group was significantly higher than that of the control group, there was statistical significance (P< 0. 05 ). Corneal endothelial cell density showed apparent difference of the two groups before and after surgery;at 1, 3, 7d and 1mo after operation, data of the observation group was significantly lower than that of the control group, there was statistical significance ( P<0. 05).· CONCLUSION: Phacoemulsification has significant effects on tear film break-up time, SⅠt and dry eye symptoms in patients with diabetes mellitus, which may be related to the impaired repair ability of diabetic patients.

Mechanical strain effects on black phosphorus nanoresonators.

We perform classical molecular dynamics simulations to investigate the effects of mechanical strain on single-layer black phosphorus nanoresonators at different temperatures. We find that the resonant frequency is highly anisotropic in black phosphorus due to its intrinsic puckered configuration, and that the quality factor in the armchair direction is higher than in the zigzag direction at room temperature. The quality factors are also found to be intrinsically larger than those in graphene and MoS2 nanoresonators. The quality factors can be increased by more than a factor of two by applying tensile strain, with uniaxial strain in the armchair direction being the most effective. However, there is an upper bound for the quality factor increase due to nonlinear effects at large strains, after which the quality factor decreases. The tension induced nonlinear effect is stronger along the zigzag direction, resulting in a smaller maximum strain for quality factor enhancement.

Molecularly imprinted polymeric stir bar: Preparation and application for the determination of naftopidil in plasma and urine samples.

In this study, molecularly imprinting technology and stir bar absorption technology were combined to develop a microextraction approach based on a molecularly imprinted polymeric stir bar. The molecularly imprinted polymer stir bar has a high performance, is specific, economical, and simple to prepare. The obtained naftopidil-imprinted polymer-coated bars could simultaneously agitate and adsorb naftopidil in the sample solution. The ratio of template/monomer/cross-linker and conditions of template removal were optimized to prepare a stir bar with highly efficient adsorption. Fourier transform infrared spectroscopy, scanning electron microscopy, selectivity, and extraction capacity experiments showed that the molecularly imprinted polymer stir bar was prepared successfully. To utilize the molecularly imprinted polymer stir bar for the determination of naftopidil in complex body fluid matrices, the extraction time, stirring speed, eluent, and elution time were optimized. The limits of detection of naftopidil in plasma and urine sample were 7.5 and 4.0 ng/mL, respectively, and the recoveries were in the range of 90-112%. The within-run precision and between-run precision were acceptable (relative standard deviation <7%). These data demonstrated that the molecularly imprinted polymeric stir bar based microextraction with high-performance liquid chromatography was a convenient, rapid, efficient, and specific method for the precise determination of trace naftopidil in clinical analysis.

Applications of magnetic surface imprinted materials for solid phase extraction of levofloxacin in serum samples.

In this work, molecularly imprinted magnetic carbon nanotubes (MCNTs@MIPs) was prepared with surface imprinting technique for extraction of levofloxacin in serum samples. The preparation of molecularly imprinted polymers (MIPs) used levofloxacin as template, methacrylic acid as functional monomer, and ethylene glycol dimethacrylate as cross-linker, and the magnetic carbon nanotubes (MCNTs) was synthesized by solvothermal method. The prepared polymers not only can be separated and collected easily by an external magnetic, but also exhibited high specific surface area and high selectivity to template molecules. Kinetic adsorption and static adsorption capacity investigations indicated that the synthesized MCNTs@MIPs had excellent recognition towards levofloxacin. Furthermore, magnetic solid phase extraction (MSPE) using the prepared MCNTs@MIPs as sorbent was then investigated, and an efficient sample cleanup was obtained with recoveries ranged from 78.7 ± 4.8 % to 83.4 ± 4.1%. In addition, several parameters, including the pH of samples, the amount of MCNTs@MIPs, the adsorption and desorption times, and the eluent, were investigated to obtain optimal extraction efficiency. Under the optimal extraction conditions, the stability of the polymer was also evaluated, and the average recovery reduced less than 7.6% after 5 cycles. MCNTs@MIPs successfully applied in the preconcentration and determination of levofloxacin in serum sample suggested that the MSPE method based on the novel polymers could be a promising alternative for selective and efficient extraction of trace amounts of pharmaceutical substances in bio-matrix samples.

Construction of cDNA expression library of watermelon for isolation of ClWRKY1 transcription factors gene involved in resistance to Fusarium wilt.

Full-length cDNAs are very important for genome annotation and functional analysis of genes. The number of full-length cDNAs from watermelon remains limited. Here we report first the construction of a full-length enriched cDNA library from Fusarium wilt stressed watermelon (Citrullus lanatus Thunb.) cultivar PI296341 root tissues using the SMART method. The titer of primary cDNA library and amplified library was 2.21 x 10(6) and 2.0 x 10(10) pfu/ml, respectively and the rate of recombinant was above 85%. The size of insert fragment ranged from 0.3 to 2.0 kb. In this study, we first cloned a gene named ClWRKY1, which was 1981 bp long and encoded a protein consisting of 394 amino acids. It contained two characteristic WRKY domains and two zinc finger motifs. Quantitative real-time PCR showed that ClWRKY1 expression levels reached maximum level at 12 h after inoculation with Fusarium oxysporum f. sp. niveum. The full-length cDNA library of watermelon root tissues is not only essential for the cloning of genes which are known, but also an initial key for the screening and cloning of new genes that might be involved in resistance to Fusarium wilt.

[Effect of protein on the detection of antipsychotic drug residues in human serum and its elimination].

Using pure human serum albumin (HSA) as the model protein, the effects of protein on the extraction of antipsychotic drugs (APDs: diazepam, chlorpromazine hydrochloride, and perphenazine) in human serum sample were studied. The present paper investigated the interaction between APDs and HSA by fluorescence spectrometry in detail The influences of different ethanol concentration solution on protein denaturation were studied by Rayleigh scattering. The results showed that APDs strongly bound with HSA. In the phi (ethanol) 80% extracting solution, a slow but full protein denaturation takes place, which causes the unfolding of protein and the dissociation of drugs. Then K2 HPO4 was added into the extracting solution to form aqueous two-phase system, and meanwhile the drug residues were extracted into upper phase with high extraction efficiencies. After filtration, the upper phase was ready for analysis of drug residues by HPLC system. The detection limits were in the range of 18.8-38.4 ng x mL(-1), and the spiked recovery was 94.2%-98.7% for determination of antipsychotic drugs in human serum. The method is efficient, solvent-saving, environment-friendly, and accurate.

Age-associated reduction of asymmetry in human central auditory function: a 1H-magnetic resonance spectroscopy study.

The aim of this study was to investigate the effects of age on hemispheric asymmetry in the auditory cortex after pure tone stimulation. Ten young and 8 older healthy volunteers took part in this study. Two-dimensional multivoxel 1H-magnetic resonance spectroscopy scans were performed before and after stimulation. The ratios of N-acetylaspartate (NAA), glutamate/glutamine (Glx), and γ -amino butyric acid (GABA) to creatine (Cr) were determined and compared between the two groups. The distribution of metabolites between the left and right auditory cortex was also determined. Before stimulation, left and right side NAA/Cr and right side GABA/Cr were significantly lower, whereas right side Glx/Cr was significantly higher in the older group compared with the young group. After stimulation, left and right side NAA/Cr and GABA/Cr were significantly lower, whereas left side Glx/Cr was significantly higher in the older group compared with the young group. There was obvious asymmetry in right side Glx/Cr and left side GABA/Cr after stimulation in young group, but not in older group. In summary, there is marked hemispheric asymmetry in auditory cortical metabolites following pure tone stimulation in young, but not older adults. This reduced asymmetry in older adults may at least in part underlie the speech perception difficulties/presbycusis experienced by aging adults.

Determination of phenformin hydrochloride using molecular imprinting technology coupled with flow-injection chemiluminescence.

A novel method was developed using molecular imprinting technology (MIT) coupled with flow-injection chemiluminescence (FI-CL) for highly sensitive detection of phenformin hydrochloride (PH). The phenformin imprinted polymer was synthesized with methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as a cross-linker. Newly synthesized molecularly imprinted polymer (MIP) particles were packed into a column as a selective recognition element for determination of PH. A CL method for the determination of PH was developed based on the CL reaction of PH with N-bromosuccinimide sensitized by eosin Y in basic media. The optimization of detection conditions was investigated. The CL intensity responded linearly to the concentration of PH in the range 0.09-2.0 µg/mL, with a correlation coefficient of 0.9920. The detection limit was 0.031 µg/mL. The relative standard deviation for the determination of 1.0 µg/mL PH solution was 1.0% (n = 11). The method was applied to the determination of PH in urine samples, with satisfactory results.

[The association between vitamin D and bone mineral density of urban postmenopausal women in Beijing].

OBJECTIVE: To study the association between vitamin D status and bone mineral density(BMD) in urban postmenopausal women in Beijing. METHODS: A total of 400 community-dwelling women older than 60 (median age 67.8 years) were selected randomly from 17 community of 3 districts in Beijing by cluster sampling method from May to July, 2008. Serum 25(OH)D concentrations were measured by radioimmunoassay, using the DiaSorin kit, America. The objects were assigned into four groups: vitamin D deficient group (group A, 25(OH)D < 25 nmol/L), insufficient group(group B, 25 nmol/L < 25(OH)D < or = 50 nmol/L), normal group (group C, 50 nmol/L < 25(OH)D < or = 75 nmol/L) and enough group (group D, 25(OH)D > 75 nmol/L). The BMD at total, lumbar spine (L(2-4)) and proximal femur were measured by dual-energy X-ray absorptiometry (DEXA). RESULTS: The mean concentration of serum 25(OH)D concentration was (36.0 +/- 14.6) nmol/L, BMD at total and proximal femur were respectively (0.829 +/- 0.090) and (0.679 +/- 0.106) g/cm(2). The mean BMD at total of group A, B, C + D were respectively (0.811 +/- 0.077), (0.825 +/- 0.088) and (0.864 +/- 0.112) g/cm(2)(F = 16.93, P < 0.01), and BMD at proximal femur of group A, B, C + D were respectively (0.666 +/- 0.107), (0.673 +/- 0.099) and (0.725 +/- 0.117) g/cm(2)(F = 18.36, P < 0.01). The 25(OH)D level was positively correlated with BMD at total body and proximal femur (r values were 0.17 and 0.18, both P values < 0.05). CONCLUSION: Vitamin D status was highly correlated with BMD at lumbar spine (L(2-4)), proximal femur, pelvis and limbs for the postmenopausal older women.