Local-environment-guided selection of atomic structures for the development of machine-learning potentials.

Machine learning potentials (MLPs) have attracted significant attention in computational chemistry and materials science due to their high accuracy and computational efficiency. The proper selection of atomic structures is crucial for developing reliable MLPs. Insufficient or redundant atomic structures can impede the training process and potentially result in a poor quality MLP. Here, we propose a local-environment-guided screening algorithm for efficient dataset selection in MLP development. The algorithm utilizes a local environment bank to store unique local environments of atoms. The dissimilarity between a particular local environment and those stored in the bank is evaluated using the Euclidean distance. A new structure is selected only if its local environment is significantly different from those already present in the bank. Consequently, the bank is then updated with all the new local environments found in the selected structure. To demonstrate the effectiveness of our algorithm, we applied it to select structures for a Ge system and a Pd13H2 particle system. The algorithm reduced the training data size by around 80% for both without compromising the performance of the MLP models. We verified that the results were independent of the selection and ordering of the initial structures. We also compared the performance of our method with the farthest point sampling algorithm, and the results show that our algorithm is superior in both robustness and computational efficiency. Furthermore, the generated local environment bank can be continuously updated and can potentially serve as a growing database of feature local environments, aiding in efficient dataset maintenance for constructing accurate MLPs.

Epidemiology and antifungal susceptibility of fungal infections from 2018 to 2021 in Shandong, eastern China: A report from the SPARSS program.

PURPOSE: We analyzed the pathogenic fungal epidemiology and antifungal susceptibility from 2018 to 2021 in Shandong Province, China, to provide the basis for empiric antifungal therapy. METHODS: Fungal isolates were collected from 54 hospitals in Shandong province from 2018 to 2021 through the Shandong Province Pediatric bacterial & fungal Antimicrobial Resistance Surveillance System (SPARSS), WHONET v5.6 and SPSS software v20.0 were used for statistical analysis. RESULTS: A total of 15,348 strains of fungi were collected, with Candida accounting for 78.25 %, followed by Aspergillus at 15.45 %, and other species at 6.27 %. Candida albicans was the predominant Candida species, but more than half of the Candida isolates were non-albicans species, with C. tropicalis being the most dominant (22.74 %), followed by C. glabrata (17.50 %) and C. parapsilosis (11.02 %). The composition of fungi varied significantly among different age groups. Children had a higher proportion of C. albicans (47.30 %) compared to non-children (32.06 %). The non-wild-type phenotype rate of Candida for Amphotericin B was less than 3 %, while Cryptococcus neoformans was 16.67 %. In addition, less than 6 % of C. albicans and C. parapsilosis were resistant to fluconazole and voriconazole, and 96.30 % of C. glabrata were SDD to fluconazole. We also found that 80.56 % of C. glabrata and 83.70 % of C. krusei were voriconazole WT/susceptibility phenotype. However, the susceptibility rates of C. tropicalis to fluconazole/voriconazole decreased from 70.40 %/46.40 % in 2018 to 62.30 %/35.20 % in 2021. The comprehensive susceptibility rate to fluconazole of C. albicans, C. tropicalis, C. parapsilosis and C. glabrata isolated from the blood has decreased from 69.36 % to 56.62 %. CONCLUSIONS: The study reveals that the composition and antifungal susceptibility of pathogenic fungi in Shandong Province differ from other regions. Moreover, the resistance to azoles is more severe, especially in C. tropicalis. These findings indicate the need for region-specific antifungal treatment strategies to combat fungal infections effectively.

Research on odor characteristics of typical odorants of railway vehicle products.

Odor annoyance was a kind of environmental air pollution. Compared to other indoor environments, vehicle interior materials were not well studied. Especially, there had been little research on odor character of the railway vehicles. This study applied the OAV method to identify the key odorants of railway vehicle materials and discussed the characteristics of these odorants through Weber Fechner law and a dual variable method. The result showed that for single odorant, Weber Fechner law can be used to estimate the perceived intensity of an odor gas sample at different concentration levels. The odorant with smaller slope had significant tolerance to human. For the mixtures of odorants, the overall intensity of the mixture is generally dominated by the strongest odor intensity of the individual substance in the mixture, and positive interaction effect can be observed in mixtures whose intensities had little difference. But there was a kind of odorants, such as methacrylate, in which a very small variation in the concentration of mixtures can affect its odor intensity largely. Meanwhile, the odor intensity modification coefficient was an effective way to identify and evaluate odor interaction effect. The interaction potential of the studied odorants from strong to weak was methacrylate, dibutyl-amine, nonanal, 2-ethyl hexanol. The odor interaction potential and odor nature should be paying much attention in the improvement of odor in railway vehicle product.

Virulence capacity of different Aspergillus species from invasive pulmonary aspergillosis.

Introduction: The opportunistic filamentous fungus Aspergillus causes invasive pulmonary aspergillosis (IPA) that often turns into a fatal infection in immunocompromised hosts. However, the virulence capacity of different Aspergillus species and host inflammation induced by different species in IPA are not well understood. Methods: In the present study, host inflammation, antimicrobial susceptibilities and virulence were compared among clinical Aspergillus strains isolated from IPA patients. Results: A total of 46 strains were isolated from 45 patients with the invasive infection, of which 35 patients were diagnosed as IPA. Aspergillus flavus was the dominant etiological agent appearing in 25 cases (54.3%). We found that the CRP level and leukocyte counts (elevated neutrophilic granulocytes and monocytes, and reduced lymphocytes) were significantly different in IPA patients when compared with healthy individuals (P < 0.05). Antifungal susceptibilities of these Aspergillus isolates from IPA showed that 91%, 31%, 14%, and 14% were resistant to Fluconazole, Micafungin, Amphotericin B and Terbinafine, respectively. The survival rate of larvae infected by A. flavus was lower than larvae infected by A. niger or A. fumigatus (P < 0.05). Discussion: Aspergillus flavus was the dominant clinical etiological agent. Given the prevalence of A. flavus in our local clinical settings, we may face greater challenges when treating IPA patients.

Correlation Between Drug Resistance and Virulence of Candida Isolates from Patients with Candidiasis.

Purpose: This article aims to provide a theoretical basis for new or adjuvant strategies to facilitate the early diagnosis and treatment of candidiasis and to determine if drug-resistant Candida would affect virulence. Patients and Methods: Our strains were collected from patients diagnosed with candidiasis in our hospital. The strains were identified by MALDI-TOF system and ITS sequencing. Antifungal sensitivity testing in vitro was performed to evaluate susceptibility of these isolates to current widely used antifungal drugs. The Galleria mellonella larvae model infected by Candida spp. was used to compare the virulence of drug-resistant and susceptible Candida spp. Results: A total of 206 Candida strains were collected from clinical specimens. Candida albicans was the most common species among them, and was predominantly isolated from male patients aged over 40 years in ICU environments suffering from pulmonary and/or cerebral conditions. The accuracy rate of MALDI TOF-MS identification was 92.72% when compared with ITS sequencing as the standard method. Most Candida species, except for C. tropicalis which showed high resistance to micafungin, showed high susceptibilities to voriconazole, itraconazole, amphotericin B and micafungin but were highly resistant to terbinafine. For each specific Candida species, the G. mellonella larvae model revealed that the virulence of drug-resistant Candida isolates did not markedly differ from that of the drug-susceptible isolates, however, the virulence was dose-dependent on inoculated fungal cells in this model. Conclusion: The possibility of Candida infection should not be neglected in patients at critical care hospital settings and C. albicans is the most common causative agent. MALDI-TOF MS has the advantages of rapidity and high accuracy, and should be a preferred method for identification of Candida spp. in a clinical laboratory. Voriconazole, itraconazole, amphotericin B and micafungin can still be recommended as the first line antifungals to treat candidiasis.

Tailoring Dirac Fermions by In-Situ Tunable High-Order Moiré Pattern in Graphene-Monolayer Xenon Heterostructure.

We report an experimental study of a high-order moiré pattern formed in graphene-monolayer xenon heterostructure. The moiré period is in situ tuned from few nanometers to +∞, by adjusting the lattice constant of the xenon monolayer through annealing. Using angle-resolved photoemission spectroscopy, we observe that Dirac node replicas move closer and finally overlap with a gap opening, as the moiré pattern expands to +∞ and evolves into a Kekulé distortion. A moiré Hamiltonian coupling Dirac fermions from different valleys explains experimental results and indicates narrow moiré band. Our Letter demonstrates a platform to study continuous evolution of the moiré pattern, and provides an unprecedented approach for tailoring Dirac fermions with tunable intervalley coupling.

Evaluation of Droplet Digital PCR Assay for the Diagnosis of Candidemia in Blood Samples.

Numerous studies have shown that droplet digital PCR (ddPCR) is a promising tool for the diagnosis of pathogens, especially in samples with low concentrations of pathogenic DNA. An early diagnosis of candidemia is critical for the effective treatment of patients. In this study, we evaluated the sensitivity and specificity of ddPCR assay for Candida DNA detection both in vitro by mixing fungal cells with human blood and in vivo by analyzing blood samples from infected mice and patients with suspected candidemia. The results showed that ddPCR assay could detect a minimum of 4.5 DNA copies per reaction in blood samples. ddPCR showed higher sensitivity and specificity for Candida DNA detection than traditional culture and quantitative PCR (qPCR) methods and also exhibited significantly better positive and negative predictive values than the culture and qPCR methods that were commonly used in clinical practice. Hence, our study demonstrates that ddPCR assay is a promising method for the timely diagnosis of candidemia and could be useful for monitoring the treatment of candidemia.

Rapid detection of fungi from blood samples of patients with candidemia using modified calcofluor white stain.

We reported a modified CFW assay for rapid detection of fungi in blood samples and evaluated its efficacy in vivo and in vitro. The positive rate, sensitivity, and negative predictive values of the modified CFW method were all significantly higher than those of traditional fungal culture and KOH methods.

Site-switchable mono-O-allylation of polyols.

Site-selective modification of complex molecules allows for rapid accesses to their analogues and derivatives, and, therefore, offers highly valuable opportunities to probe their functions. However, to selectively manipulate one out of many repeatedly occurring functional groups within a substrate represents a grand challenge in chemistry. Yet more demanding is to develop methods in which alterations to the reaction conditions lead to switching of the specific site of reaction. We report herein the development of a Pd/Lewis acid co-catalytic system that achieves not only site-selective, but site-switchable mono-O-allylation of polyols with readily available reagents and catalysts. Through exchanging the Lewis acid additives that recognize specific hydroxyls in a polyol substrate, our system managed to install a versatile allyl group to the target in a site-switchable manner. Our design demonstrates remarkable scope, and is amenable to the direct derivatization of various complex, bioactive natural products.

Diastereo- and Enantioselective Propargylation of 5H-Thiazol-4-ones and 5H-Oxazol-4-ones as Enabled by Cu/Zn and Cu/Ti Catalysis.

Reported is the asymmetric propargylic substitution (APS) reaction of 5H-thiazol-4-ones using a Cu/Zn dual metal catalytic system and the APS reaction of 5H-oxazol-4-ones using a Cu/Ti catalytic system. These reactions furnish functional-group-rich, terminal-alkyne-containing products with two vicinal stereocenters in high yields and with good to excellent diastereo- and enantioselectivities. This study demonstrates the use of dual metal catalytic systems as a viable approach to improve the selectivity profiles of the copper-catalyzed APS reactions.

Diagnostic value of T-Spot TB combined with INF-γ and IL-27 in tuberculous pleurisy.

The purpose of the present study was to investigate the diagnostic value of T cells spot test (T-Spot TB) combined with interferon-γ (INF-γ) and interleukin-27 (IL-27) in tuberculous pleurisy. Sixty patients with tuberculous pleurisy (observation group) and 60 patients with non-tuberculous pleurisy (control group) were enrolled in this study. T-Spot TB was performed to detect the pleural effusion of two groups of patients. Levels of IFN-γ and IL-27 in serum and pleural effusion were detected by enzyme-linked immunosorbent assay (ELISA). Relative expression of IFN-γ mRNA and IL-27 mRNA in peripheral blood mononuclear cells were detected by RT-PCR. Positive rate of T-Spot TB in observation group was 96.7% (58 cases), which was significantly higher than that in control group (p<0.05). Concentration of INF-γ in pleural effusion of observation group was 468.6±24.8 ng/l, which was significantly higher than that in control group (131.3±18.7 ng/l, p<0.05). Concentration of IL-27 in pleural effusion of observation group was 423.4±37.2 ng/l, which was significantly higher than that in control group (116.2±15.5 ng/l, p<0.05). Concentrations of INF-γ and IL-27 in serum of observation group were 48.2±13.4 and 41.7±10.6 ng/l, respectively, which were significantly higher than those in control group (38.6±11.2 and 35.3±8.4 ng/l, p<0.05). Relative expression levels of INF-γ mRNA and IL-27 mRNA in observation group were significantly higher than those in control group (p<0.05). Therefore, combination of T-Spot TB with INF-γ and IL-27 has significant application value in the clinical diagnosis of tuberculous pleurisy, and should be popularized.

Enantioselective Propargylation of Polyols and Desymmetrization of meso 1,2-Diols by Copper/Borinic Acid Dual Catalysis.

A copper/borinic acid dual catalytic reaction enabled the enantioselective propargylation of aliphatic polyols. Readily available reagents and catalysts were used in this transformation, which displayed good to excellent chemo- and stereoselectivity for a broad array of substrates. The method was also applicable to the desymmetrization of meso 1,2-diols to furnish products with three stereogenic centers and a terminal alkyne group in one operation.

Overexpression of visfatin/PBEF/Nampt alters whole-body insulin sensitivity and lipid profile in rats.

BACKGROUND: Visfatin/PBEF/Nampt is an adipose-derived hormone proposed to exert insulin-mimicking effects and play a positive role in attenuating insulin resistance. However, the precise mechanisms underlying the beneficial effects of visfatin/PBEF/Nampt on insulin sensitivity remain unknown. METHOD: Euglycemic-hyperinsulinemic clamps were used in the same groups of rats to study the in vivo effect of visfatin/PBEF/Nampt on insulin sensitivity and glucose/lipid metabolism before and after the overexpression of visfatin/PBEF/Nampt protein, which was carried out by injection of pcDNA3.1-visfatin plasmid. RESULTS: On day 4 after plasmid injection, plasma visfatin/PBEF/Nampt protein levels were significantly increased and displayed a hypocholesterolemic effect in both normal-chow (NC) and high-fat diet (HT) animals with pcDNA3.1-visfatin treatment. A second glucose clamp also demonstrated increased insulin sensitivity in pcDNA3.1-visfatin animals. Consistent with the clamp data, the extent of insulin receptor substrate (IRS)-1 tyrosine phosphorylation in response to insulin was significantly enhanced in the liver and adipose tissues. In addition, the mRNA expression of peroxisome proliferator-activated receptor-gamma (PPARgamma) and sterol regulatory element-binding proteins 2 (SREBP-2) in the liver and adipose tissues was also significantly upregulated in these animals. CONCLUSION: These results demonstrate that visfatin/PBEF/Nampt improves insulin sensitivity and exerts its hypocholesterolemic effects at least partially through upregulation of the tyrosine phosphorylation of IRS-1 protein and the mRNA levels of PPARgamma and SREBP-2.

[Effects of visfatin gene overexpression on insulin sensitivity in the insulin-resistant rats induced by high-fat diet].

OBJECTIVE: To investigate the effects of visfatin gene overexpression on insulin sensitivity in insulin-resistant (IR) rats induced by high-fat diet. METHODS: The recombinant visfatin plasmid was constructed and transfected into IR rats induced by high-fat diet. The euglycemic-hyperinsulinemic clamp experiments were performed for evaluation the change of insulin sensitivity before and after administration. RESULTS: The expression plasmid of visfatin were successfully constructed. After 3 days for plasmid injecting, plasma visfatin levels and glucose infusion rates were significantly increased (2.19 +/- 0.36 vs 0.98 +/- 0.27 and 32.6 +/- 1.2 vs 24.0 +/- 1.2 mg x kg(-1) x min(-1), respectively, all P < 0.01), and total cholesterol and high-density lipoprotein cholesterol (HDL-C) were significantly decreased (2.36 +/- 0.22 vs 1.60 +/- 0.21 mmol/L and 1.41 +/- 0.24 vs 0.88 +/- 0.11 mmol/L, respectively, all P < 0.05) in high-fat diet rats. CONCLUSION: The transfection of visfatin plasmid enhanced plasma visfatin level and improved insulin sensitivity in IR rats induced by high-fat diet.