[Correlation of extracellular enzymes activity of Candida glabrata clinical isolates with in vivo pathogenicity in Galleria mellonella larvae].

Objective: To explore the relationship between extracellular enzymes activity and virulence of Candida glabrata clinical isolates based on the infection model of Galleria mellonella larvae. Methods: Using experimental research methods, 71 strains of non-repetitive Candida glabrata were collected from Qinghai Provincial People's Hospital from June 2021 to January 2022. Bovine serum protein agar medium, egg yolk agar medium, sheep blood agar medium, Tween-80 agar medium and triglyceride agar medium were used to detect the aspartyl protease activity, phospholipase activity, hemolysis activity, esterase activity and lipase activity of Candida glabrata. Median lethal concentration (LC50) was calculated by using 1.25×108 CFU/ml,2.50×108 CFU/ml,3.75×108 CFU/ml,5.00×108 CFU/ml suspension of Candida glabrata ATCC2001 to infect Galleria mellonella larvae. Histopathological and etiological analysis was performed to determine whether the infection model was successfully established. The clinical isolates of Candida glabrata were configured to infect Galleria mellonella larvae with LC50 concentration to detect the pathogenicity of Galleria mellonella larvae.Spearman test or Pearson test were used to analyze the correlation between the extracellular enzyme activity of Candida glabrata clinical isolates and the pathogenicity of Galleria mellonella larvae. Results: 71 strains of Candida glabrata isolated clinically were detected to have low hemolytic activity after 2 days of culture. Aspartyl protease was detected after 4 days of culture, among which 7 strains (9.86%), 19 strains (26.76%) and 45 strains (63.38%) showed low, medium and high aspartyl protease activity. After 7 days of culture, 71 strains did not detect phospholipase, esterase and lipase activities. Candida glabrata on Galleria mellonella larvae of LC50=2.5×108 CFU/ml Fungal spore were found in the intestinal tissue pathological section of Galleria mellonella larvae in the experimental group, and Candida glabrata was identified by the microbial Mass Spectrometry after culture, while no fungi were found in the pathological section and culture of the control group. Spearman test shows that, there was a linear positive correlation between aspartyl protease activity and the survival rate of Galleria mellonella larvae (r = 0.73, P<0.01), the difference was statistically significant.Pearson test shows that, there was no significant linear relationship between hemolytic activity and survival rate of Galleria mellonella larvae (r = 0.16, P = 0.34), the difference was not statistically significant. Conclusion: The clinical isolates of Candida glabrata in this study had aspartyl protease activity and low hemolytic activity, but no phospholipase, esterase and lipase activity. The activity of aspartyl aspartyl protease of Candida glabrata was positively correlated with the pathogenicity of Galleria mellonella larvae.

[Epidemiologic characteristics and drug resistance of isolated from blood culture escherichia coli in a hospital in Qinghai Province from 2016 to 2022].

Objective: To explore the drug resistance of Isolated From Blood Culture Escherichia coli (E. coli) in a hospital in Qinghai over the past seven years, to evaluate the ability of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to analyze the homologous origin of E. coli, and to establish a protein fingerprint library to match with it, adjuvant clinical experience medication so as to provide the basis for the prevention and control of hospital-acquired infections. Methods: Retrospective analysis of blood cultures sent to hospitals from January 2016 to December 2022. Drug resistance and resistance changes in E. coli.A total of 1 841 E. coli strains were isolated from Qinghai Provincial People's Hospital from January 2016 to December 2022; all strains were identified by MALDI-TOF MS, and the VITEK2.0 drug sensitivity analyzer was applied for drug sensitivity analysis of the strains, and the mass spectrometry homology analysis and self-constructed protein fingerprint library were carried out by MALDI-Biotyper software; the protein fingerprint library was built by using WHONET5.6 software was used to statistically analyze the drug sensitivity results, SPSS23.0 software was used to analyze the relationship between fingerprint typing and drug sensitivity, and the χ2 test was used for intergroup comparisons. Results: A total of 1 841 strains of E. coli were detected in 4 582 positive blood culture specimens from January 2016 to December 2022, with a detection rate of 40.17%; the resistance rate of E. coli from blood sources to piperacillin/tazobactam and ceftriaxone was on the rise, and it was slightly decreased to cefepime, amikacin, levofloxacin, and sulfamethoxazole, and there was not much change to the rest of the drugs; After MALDI-Biotyper clustering analysis, the 1841 E. coli strains from Isolated From Blood Culture were classified into two major clusters and five subtypes, of which type Ⅰa1 accounted for about 40%, type Ⅰa2 accounted for about 2.7%, type Ⅰb accounted for about 3.8, type Ⅱa accounted for about 46%, and type Ⅱb accounted for about 7.5%. The detection rate of type Ⅰa1 E. coli was higher in general surgery (50.45%) and emergency surgery (50.92%), and the detection rate of type Ⅰb E. coli was higher in emergency medicine(10.05%)than in other departments. The drug sensitivity results of different subtypes were compared with each other, the resistance rate of type Ⅰa1 E. coli to cefepime was 21.3% higher than that of the remaining four types, and the difference was statistically significant (χ2=37.74,P=0.000); the resistance rate of type Ⅱ E. coli(>60%) to sulfamethoxazole was higher than that of type Ⅰ (<60%) as a whole, and the difference was statistically significant (χ2=15.248,P=0.004); and a preliminary database of homologous protein fingerprints of E. coli has been established E. coli homologous protein fingerprint library and validated. The drug susceptibility results of 1 288 E. coli strains in the validation set were statistically analyzed and compared with those in the training set. There was no significant difference(P>0.05). Conclusion: In recent years, the resistance rate of E. coli isolated from a hospital in Qinghai province to piperacillin/Tazobactam, cefepime, amicacin and other antibiotics has changed greatly. A fingerprint database of E. coli homologous protein was established, and it was found that the drug sensitivity data of E. coli were different among different fingerprint types. According to drug sensitivity, drug use could assist clinical experience and provide evidence for prevention and control of hospital illness.

[Regulation of cell deformation induced by RhoA/ROCK signaling pathway in osteogenic differentiation of human mesenchymal stem cells].

Objective: To investigate whether the cell deformation induced by RhoA/ROCK signaling pathway plays a regulatory role in the osteogenic differentiation in human mesenchymal stem cells (hMSCs). Methods: The primary hMSCs were cultured until the P3 generation was added to the osteogenic induction solution for 14 days, and the expression levels of RhoA and ROCK-1 proteins were detected by immunofluorescence. Another P3 generation hMSCs cells were divided into induction group, blank plus drug group and medicated group, and the induction group was induced by simple osteogenic induction; the blank drug-added group was added to the osteogenic induction solution and the solvent dimethyl sulfoxide (DMSO) for induction culture; the medicinal group was added with osteogenic induction solution and Y-27632 (RhoA/ROCK signaling pathway inhibitor) dissolved in DMSO for induction culture. The proliferation of the cells was detected by CCK-8 methods. The changes of cytoskeleton in each group were observed by fluorescence microscope. The expression changes of osteogenic genes alkaline phosphatase (ALP), osteocalcin (OCN) and runt-relatedtranscriptionfactor-2 (RUNX-2) in each group were detected by real time polymerase chain reaction (RT-PCR) and ALP staining. The t test was used for data comparison between the two groups. Results: There were significant differences in the expression of RhoA and ROCK-1 protein before and after osteogenic induction of hMSCs (22.7±2.1 vs 14.7±0.6 and 24.3±1.5 vs 20.3±0.6, t=-6.414, -4.243, both P<0.05). Mesenchymal stem cell proliferation on day 1, 5, 9 and day 14 in the medicated group were comparable with those in the induction group (F=0.427, 1.000, 0.298, 1.314, all P>0.05). The cytoskeleton of the medicated group showed obvious spindle-shaped changes, and the cell spreading area became smaller. From the three groups of ALP staining on the 14th day, it can be seen that the color of the medicated group was significantly lighter than that of the induction group. The results of RT-PCR showed that the expression of osteogenic phenotypic genes increased with the induction time in the induction group and the blank drug-treated group, the expression levels of osteogenic phenotype genes ALP, OCN and RUNX-2 in the drug-treated group were gradually decreased with the induction time. The expression of ALP in the drug-treated group was significantly lower than those in the other two groups at 14th day (F=25.891, P=0.001); the expression of OCN in the drug-treated group was significantly lower than those in the other two groups at 11th and 14th days (F=5.773, 25.382, both P<0.05); the expression of RUNX-2 in the drug group was significantly lower than those in the other two groups at 11th and 14th days (F=34.972,10.808, both P<0.05). Conclusion: The RhoA/ROCK signaling pathway may play a role in promoting osteogenic differentiation of hMSCs through mediating cytoskeletal deformation.

Ubiquitous formation of bulk Dirac cones and topological surface states from a single orbital manifold in transition-metal dichalcogenides.

Transition-metal dichalcogenides (TMDs) are renowned for their rich and varied bulk properties, while their single-layer variants have become one of the most prominent examples of two-dimensional materials beyond graphene. Their disparate ground states largely depend on transition metal d-electron-derived electronic states, on which the vast majority of attention has been concentrated to date. Here, we focus on the chalcogen-derived states. From density-functional theory calculations together with spin- and angle-resolved photoemission, we find that these generically host a co-existence of type-I and type-II three-dimensional bulk Dirac fermions as well as ladders of topological surface states and surface resonances. We demonstrate how these naturally arise within a single p-orbital manifold as a general consequence of a trigonal crystal field, and as such can be expected across a large number of compounds. Already, we demonstrate their existence in six separate TMDs, opening routes to tune, and ultimately exploit, their topological physics.

Melt fluxing to elevate the forming ability of Al-based bulk metallic glasses.

Salt-fluxing treatment is an effective technique to improve the glass-forming ability (GFA) of bulk metallic glass (BMG)-forming melts, as demonstrated before in Pd- and Fe-based systems. However, it has been challenging to develop similar fluxing protocol for more reactive melts, such as Al-rich BMG-forming systems. Here we design new fluxing agents, from a thermodynamics perspective that takes into account combined effects of physical absorption and chemical absorption (reaction) between the fluxing agents and oxide inclusions. MgCl2-CaCl2 composite salts were selected, and their fluxing effects were systematically studied on an Al86Ni6.75Co2.25Y3.25La1.75 alloy, the best BMG-forming composition reported thus far for Al-rich alloy systems. The oxygen content was found to continuously decrease in the master alloy with increasing cycles of salt-fluxing treatment, with chlorate products on the surface suggesting concurrent physical absorption and chemical reaction. The fluxing treatment developed has enabled a record critical size (diameter) of 2.5 mm for Al-based BMGs. Our finding is thus an advance in developing highly desirable Al-based BMGs, and also provides guidance for designing processing protocol to produce larger-sized BMGs in other reactive systems.

Effect of hydrogen on semiconductive properties of passive film on ferrite and austenite phases in a duplex stainless steel.

Hydrogen effect on semiconductivity and compositions of passive films formed on ferrite and austenite phases in a duplex stainless steel were investigated by current sensing atomic force microscopy and X-ray photoelectron spectroscopy. It is demonstrated that hydrogen significantly increases the conductivity of passive film due to the increase of OH-/O2- ratio. The passive film on austenite has higher conductivity than that on ferrite after hydrogen charging due to more hydrogen in austenite. The presence of hydrogen causes an inversion of conductivity type of passive film from p-type to n-type, attributed to the chemical composition change.

Magnetic Field-Induced Insulator-Semimetal Transition in a Pyrochlore Nd2Ir2O7.

We investigate magnetotransport properties in a single crystal of pyrochore-type Nd2Ir2O7. The metallic conduction is observed on the antiferromagnetic domain walls of the all-in-all-out-type Ir 5d moment ordered insulating bulk state that can be finely controlled by an external magnetic field along [111]. On the other hand, an applied field along [001] induces the bulk phase transition from insulator to semimetal as a consequence of the field-induced modification of the Nd 4f and Ir 5d moment configurations. A theoretical calculation consistently describing the experimentally observed features suggests a variety of exotic topological states as functions of electron correlation and Ir 5d moment orders, which can be finely tuned by the choice of rare-earth ion and magnetic field, respectively.

Emergence of non-centrosymmetric topological insulating phase in BiTeI under pressure.

The spin-orbit interaction affects the electronic structure of solids in various ways. Topological insulators are one example in which the spin-orbit interaction leads the bulk bands to have a non-trivial topology, observable as gapless surface or edge states. Another example is the Rashba effect, which lifts the electron-spin degeneracy as a consequence of the spin-orbit interaction under broken inversion symmetry. It is of particular importance to know how these two effects, that is, the non-trivial topology of electronic states and the Rashba spin splitting, interplay with each other. Here we show through sophisticated first-principles calculations that BiTeI, a giant bulk Rashba semiconductor, turns into a topological insulator under a reasonable pressure. This material is shown to exhibit several unique features, such as a highly pressure-tunable giant Rashba spin splitting, an unusual pressure-induced quantum phase transition, and more importantly, the formation of strikingly different Dirac surface states at opposite sides of the material.

Solitary intracranial Rosai-Dorfman disease: case report and literature review.

Rosai-Dorfman disease is a well-established autoimmune histioproliferative disorder, and solitary central nervous system involvement is rare. A 35-year-old man presented with headache and transient blurred vision of 4 months' duration and weakness of the left extremities for 1 month. He had left temporal hemianopsia, a right nasal visual field defect of the upper medial quadrant and decreased muscle strength of the left extremities. Magnetic resonance imaging (MRI) showed a contrastenhancing tentorium-based lesion in the right trigone, intruding into the right lateral ventricle. The lesion was totally resected. Rosai-Dorfman disease was confirmed pathologically by an inflammatory infiltrate in the absence of an infectious agent, emperipolesis and positive S100 staining. From a review of the literature on Rosai-Dorfman disease in the central nervous system it is concluded that follow-up MRI should be performed in order to detect possible recurrence and that this rare entity should be considered in the differential diagnosis of intracranial lesions.

Enhanced charge gap in the bilayer manganite La2-2xSr1+2xMn2O7 near x = 0.4.

We have investigated the optical conductivity spectra of La2-2xSr1+2xMn2O7 (0.3

Pseudogap dependence of the optical conductivity spectra of Ca3Ru2O7: a possible contribution of the orbital flip excitation.

Optical spectra of a double-layered perovskite ruthenate Ca3Ru2O7 show a pseudogap opening around 200 cm(-1) below 50 K, which is attributable to the partial k-space gap opening due to the density wave instability. Unlike most other density wave materials, Ca3Ru2O7 has spectral weight redistributions, not near the energy gap region, but at a much higher energy region around 800 cm(-1). As a possible origin of these intriguing features, we discuss the orbital flip excitation in the density wave ground state.

Raman spectroscopic investigation of carbon nanowalls.

Two-dimensional carbon nanowalls (CNWs) were prepared by microwave plasma-enhanced chemical-vapor deposition and scanning electron microscopy was used to observe their morphologies. The Raman observations of different sample orientations and polarizations show that CNWs are well crystallized. Micro-Raman scattering measurements were also carried out with different excitation laser lines (325, 488, 514, 532, and 633 nm). The D band shows a very strong shift of 46.19 cm(-1)eV with excitation laser energy and this has been explained by the double resonance effect. The decreasing intensity ratios IDIG and ID'/IG with increasing laser excitation energy were detected and discussed.

The measurement of solute diffusion coefficients in dilute liquid alloys: the influence of unit gravity and g-jitter on buoyancy convection.

Liquid diffusion experiments conducted on the MIR space station using the Canadian Space Agency QUELD II processing facility and the microgravity isolation mount (MIM) showed that g-jitter significantly increased the measured solute diffusion coefficients. In some experiments, milli-g forced vibration was superimposed on the sample when isolated from the ambient g-jitter; this resulted in markedly increased solute transport. To further explore the effects arising in these long capillary diffusion couples from the absence of unit-gravity and the presence of the forced g-jitter, the effects of a 1 milli-g forcing vibration on the mass transport in a 1.5 mm diameter long capillary diffusion couple have been simulated. In addition, to increase understanding of the role of unit gravity in determining the extent to which gravity can influence measured diffusion coefficient values, comparative experiments involving gold, silver, and antimony diffusing in liquid lead have been carried out using a similar QUELD II facility to that employed in the QUELD II/MIM/MIR campaign but under terrestrial conditions. It was found that buoyancy-driven convection may still persist in the liquid even when conditions are arranged for a continuously decreasing density gradient up the axis of a vertical long capillary diffusion couple due to the presence of small radial temperature gradients.

The influence of Marangoni flows on crack growth in cast metals.

In previous work with copper-based alloys, the authors showed that a necessary part of the hot-tearing process is the creation of a void in association with an inclusion and its subsequent growth to form the crack observed in the as-cast state. The work reported here is an examination of hot tearing in aluminum alloy A201 and various similar Al-based aerospace alloys to determine (1) if a similar process to that seen in copper alloys takes place; (2) the extent to which buoyancy forces influence the movement of solute-enriched liquid and so contribute to the development of voids which are subsequently observed as hot tears; and (3) the influence of the local variations in liquid/void surface tension arising due to local composition and temperature changes on interdendritic fluid flow--that is, the effects of Marangoni convection on void size and movement during solidification. Hot cracking of aluminum alloy A201 has been examined under standardized experimental conditions. In addition, experiments were conducted in which fluid flow in test castings was controlled by magnetic fields. The results from these various investigations are presented in this paper. Similar experiments are planned for reduced gravity aircraft parabolic flights. To assist in the planning and interpretation of the results, numerical modeling simulations have been developed for Al-Cu alloys.

[On molecular identification and taxonomic status of Anopheles lesteri and Anopheles anthropophagus in China (Diptera: Culicidae)].

OBJECTIVE: To clarify the taxonomic status of Anopheles lesteri and An. anthropophagus in China. METHODS: Using molecular identification (PCR assay and rDNA-ITS2 sequencing) to examine the field anopheline mosquito specimens from Liaoning and Shandong. According to the ITS2 sequences, molecular phylogenetic tree was made. RESULTS: According to the molecular identification, An. lesteri and An. anthropophagus were distributed both in Liaoning Province and Shandong Province. The length and GC content of rDNA-ITS2 sequence were 451 bp, 46.2% in An. lesteri (n = 6), and 448 bp, 46.0% in An. anthropophagus (n = 10), respectively. The ITS2 sequences from presentation sites were same in An. lesteri, while the intraspecies difference in An. anthropophagus was 0.88%. The specific difference between An. lesteri and An. anthropophagus was 25.7%. By analyzing molecular phylogenetic tree, the relationship between An. lesteri and An. sinensis, An. anthropophagus and An. liangshanensis was found to be closer. CONCLUSION: According to the molecular identification, it was defined that An. lesteri and An. anthropophagus were sympatric independent species in China.

Breathing-coordinated exercise improves the quality of life in hemodialysis patients.

Breathing-coordinated exercise is a traditional Chinese exercise. These exercise maneuvers consist of slow diaphragmatic breathing, end-inspiratory pause, and Kegel's exercise. A total of 30 patients were enrolled in this study, with 12 patients as controls, to evaluate its effect on hemodialysis patients. Exercise was performed for 25 to 30 min twice a day for at least 3 months. Results from the exercise group showed a subjective improvement in appetite and physical strength, and an increase in the frequency of bowel movements, in addition to enhanced sexual activity and a significant increase in Karnofsky scores. Six patients in the exercise group underwent bicycle ergometry and demonstrated a stable maximal oxygen consumption, whereas the control group revealed a decline in maximal oxygen consumption. Photoelectric plethysmography and laser-Doppler flowmetry demonstrated a pulsatile enhancement of the peripheral microcirculation. Abdominal sonography revealed an oscillatory change in the diameter of the inferior vena cava. It was concluded that these gentle exercise maneuvers may improve the quality of life in hemodialysis patients, especially weak dialysis patients. The mechanism may be partly related to an improvement in microcirculation.

Absence of pressure antagonism of ethanol narcosis in C. elegans.

Because hydrostatic pressure can antagonize the behavioral effects of anesthetics in many organisms, we examined whether ethanol-induced immobility of the nematode Caenorhabditis elegans was antagonized by 100 ATA pressure. Nematode mobility was examined at pressures ranging from 1 ATA to 132 ATA, with and without increasing concentrations of ethanol (0-1 M). Pressure > 100 ATA alone inhibited movement of the nematode (EP50 = 111.5 +/- 0.6 ATA), as did increasing concentrations of ethanol (EC50 = 487 +/- 44 mM). Pressure and ethanol appeared to be additive, and not antagonistic. Because of previous results implicating glycine receptor antagonism as a mechanism of pressure reversal, and our current inability to observe significant behavioral effects of strychnine or glycine inhibition of high affinity strychnine binding, we suggest that an absence of glycine receptors in these organisms is the basis for a lack of pressure antagonism of ethanol immobility.

Microsocionomics versus macrosocionomics as a model for examining suicide.

The role of social variables in suicide is examined from a microsocionomic and a macrosocionomic perspective. As an example, the influence of divorce on suicide is explored and hypothesized to differ for the individual and for the society as a whole.

The effect of war on personal aggression.

The effect of war on the suicide rate and on the relative likelihood of suicide as a proportion of total personal aggression was examined in the United States for the time period from 1933 to 1986. Once unemployment was controlled for, no effect of war was detected.