118 research outputs found
A New Species of the Genus Trimeresurus from Southwest China (Squamata: Viperidae)
Species from the Trimeresurus popeiorum complex (Subgenus: Popeia) is a very complex group. T. popeiorum is the only Popeia species known from China. During the past two years, five adult Popeia specimens (4 males, 1 female) were collected from Yingjiang County, Southern Yunnan, China. Molecular, morphological and ecological data show distinct differences from known species, herein we describe these specimens as a new species Trimeresurus yingjiangensis sp. nov Chen, Ding, Shi and Zhang, 2018. Morphologically, the new species distinct from other Popeia species by a combination of following characters: (1) dorsal body olive drab,without cross bands on the scales; (2) a conspicuous bicolor ventrolateral stripe present on each side of males, first row of dorsal scales firebrick with a white ellipse dot on posterior upper part in male, these strips absent in females; (3) eyes firebrick in both gender; (4) suboculars separated from 3rd upper labial by one scale on each side; (5) ventrals 164–168 (n = 5); (6) MSR 21
Phylogenetic and morphological analysis of Gloydius himalayanus (Serpentes, Viperidae, Crotalinae), with the description of a new species
Gloydius is a widespread pitviper group occurring from Eastern Europe to Korea and Siberia, with only one known species, G. himalayanus (GĂĽnther, 1864), found south of the Himalayas. We provide combined genetic and morphological data for G. himalayanus from specimens collected from Himachal Pradesh, India. Bayesian Inference and Maximum Likelihood phylogenetic analysis were performed on four concatenated mitochondrial genes, along with a multi-locus coalescent analysis of these and five additional nuclear genes. Our results indicate that G. himalayanus from the Chamba Valley, in western Himachal Pradesh, are highly distinct from the remaining studied populations. Haplotype networks of each nuclear locus showed that G. himalayanus contains high haplotype diversity with low haplotype sharing between the Chamba Valley population and populations from further west. Principal component analysis and canonical variate analysis conducted on morphological data of live and museum specimens also highlight the morphological distinctiveness of the Chamba population and we herein describe this population as a new species, Gloydius chambensis sp. nov. Recent descriptions of other new species of snakes from this valley underscores its isolation and suggests that further herpetological investigation of the highly dissected landscapes of the western Himalayas is needed to assess the true diversity of the region
Tribological behaviors of vacuum hot-pressed ceramic composites with enhanced cyclic oxidation and corrosion resistance
Wear failure is a bottleneck restricting applications and developments of Ti3SiC2 ceramic. Particles reinforced composites provide an effective strategy to resist wear. In this work, Ti(C,N) particles are used as reinforcements, and Ti3SiC2/Ti(C,N) composite is fabricated by vacuum hot-pressing. Scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffract meter (XRD) are used to investigate composite morphologies, compositions and phases before and after hot-pressing. Meanwhile, high-temperature cyclic oxidations and tribological behaviors of composites under various loads, speeds and Ti(C,N) contents are characterized. Results show that as-prepared composite is relatively dense, and Ti(C,N) addition plays an important role in particle reinforcement of Ti3SiC2. Meanwhile, its hardness, wear resistance, cyclic oxidation resistance and corrosion resistance are significantly improved. In addition, wear characteristics and mechanisms of composites under different loads and speeds are analyzed in details. This work shows great potentials in developing engineering applications of ceramics, especially in high-temperature, oxidizing, frictional and corrosive environment
Discriminant Analysis of Jiang-Flavor Baijiu of Different Grades by Gas Chromatography-Mass Spectrometry and Electronic Tongue
Gas chromatography-mass spectrometry (GC-MS) and electronic tongue were used to quantitatively determine the volatile compounds and taste indices of 21 Jiang-flavor baijiu samples of different grades. These samples were differentiated by chemometrics, and key differential compounds among grades were identified. Finally, a discriminant model was established by machine learning. The results showed that there were differences in the contents of volatile compounds in Jiang-flavor baijiu of three grades, indicating the feasibility of further discriminant analysis. The total content of flavor compounds in second-grade baijiu (4 908 mg/L) was significantly lower than that in premium-grade (6 583 mg/L) and first-grade baijiu (8 254 mg/L), while the proportion of several esters responsible for floral and fruity aromas in total esters showed a decreasing trend as the grade decreased. Partial least squares-discriminant analysis (PLS-DA) identified 16 key differential compounds represented by ethyl palmitate and acetic acid. The results of electronic tongue showed that the taste indexes of premium-grade baijiu were more consistent, with lower bitterness and astringency aftertaste. The taste indexes of second-grade baijiu showed significant intersample differences. Principal component analysis (PCA) showed clear discrimination of Jiang-flavor baijiu of different grades according to their taste indexes. The above results provide a basis for the establishment of Jiang-flavor baijiu quality system. Four discriminant models were established based on 25 differential compounds and taste indexes identified. The accuracy of all models was higher than 90%, and the support vector machine (SVM) model performed best, with an accuracy of 100%
New Yuomys rodents from southeastern Qinghai-Tibet Plateau indicate low elevation during the Middle Eocene
Yuomys are medium-sized Hystricomorpha rodents. They are known for coming from areas of low elevation in China during the middle and late Eocene. Two new Yuomys were discovered from a locality near Xueshuo village in Litang County, Sichuan Province. The locality lies in the Gemusi pull-apart basin formed in the Litang Fault System (LTFS) in the Hengduan Mountains. The current average elevation is about 4200 m. One of the two new Yuomys is larger and shows clear lophodont and unilateral hypsodont morphology, similar to Yuomys yunnanensis, which was discovered as being from the early middle Eocene (Irdinmanhan, Asian Land Mammal Ages) in the Chake Basin of Jianshui County, Yunnan Province. The Chake Basin is one of the small pull-apart basins formed in the Xianshuihe-Xiaojiang Fault system (XSH-XJF). The other new Yuomys rodent is smaller, brachydont, and less lophodont than the larger new species. The small new Yuomys is smaller than all known Yuomys except Yuomys huheboerhensis, which is from the early middle Eocene Irdinmanhan of Inner Mongolia in Northern China. Given their narrow biochronological distribution and presumably preferred living environment, the occurrence of Yuomys in the pull-apart basins in LTFS and XSH-XJF suggests that the two deep fault systems probably started strike-slip movement by the early middle Eocene, about 49–45 million years ago. Well-studied middle Eocene mammalian faunas from Henan and Inner Mongolia include Yuomys, primates, and other low elevation forest mammals. We suggest that the two new Yuomys species reported here probably also lived in a similar low elevation forest environment
Regulon analysis identifies protective FXR and CREB5 in proximal tubules in early diabetic kidney disease
Abstract Diabetic kidney disease (DKD) is the most common complication of diabetes mellitus and a leading cause of kidney failure worldwide. Despite its prevalence, the mechanisms underlying early kidney damage in DKD remain poorly understood. In this study, we used single nucleus RNA-seq to construct gene regulatory networks (GRNs) in the kidney cortex of patients with early DKD. By comparing these networks with those of healthy controls, we identify cell type-specific changes in genetic regulation associated with diabetic status. The regulon activities of FXR (NR1H4) and CREB5 were found to be upregulated in kidney proximal convoluted tubule epithelial cells (PCTs), which were validated using immunofluorescence staining in kidney biopsies from DKD patients. In vitro experiments using cultured HK2 cells showed that FXR and CREB5 protected cells from apoptosis and epithelial–mesenchymal transition. Our findings suggest that FXR and CREB5 may be promising targets for early intervention in patients with DKD
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