Classification of direct kinematics to planar generalized Stewart platforms

AbstractThis paper presents the classification of direct kinematics for the planar generalized Stewart platform (GSP) which consists of two rigid bodies connected by three constraints between three pairs of points or lines in the base and the moving platforms. For each of the sixteen forms of planar GSPs, we give the explicit conditions on the parameters for the GSPs to have a given number of real solutions

A triclinic polymorph with Z = 3 of N,N′-bis­(2-pyrid­yl)oxamide

The asymmetric unit of the title compound, C12H10N4O2, contains three half-mol­ecules. Each half-mol­ecule is completed by crystallographic inversion symmetry. The title compound, (I), is a polymorph of the structure, (II), reported by Hsu & Chen [Eur. J. Inorg. Chem. (2004), 1488–1493]. In the original report, the compound crystallized in the tetra­gonal space group P 21c (Z = 8), whereas the structure reported here is triclinic (P , Z = 3). In both forms, each oxamide mol­ecule is almost planar (with maximum deviations are 0.266 and 0.166 Å) and the O atoms are trans oriented. The principal difference between the two forms lies in the different hydrogen-bonding patterns. In (I), two N—H⋯O and one N—H⋯N hydrogen bonds link the mol­ecules, forming a two-dimensional network, whereas in (II) there are no classical hydrogen bonds to O atoms and only weak C—H⋯O inter­actions are found along with rings of N—H⋯N bonds

Solid reconstruction using recognition of quadric surfaces from orthographic views

International audienceThe reconstruction of 3D objects from 2D orthographic views is crucial for maintaining and further developing existing product designs. A B-rep oriented method for reconstructing curved objects from three orthographic views is presented by employing a hybrid wire-frame in place of an intermediate wire-frame. The Link-Relation Graph (LRG) is introduced as a multi-graph representation of orthographic views, and quadric surface features (QSFs) are defined by special basic patterns of LRG as well as aggregation rules. By hint-based pattern matching in the LRGs of three orthographic views in an order of priority, the corresponding QSFs are recognized, and the geometry and topology of quadric surfaces are recovered simultaneously. This method can handle objects with interacting quadric surfaces and avoids the combinatorial search for tracing all the quadric surfaces in an intermediate wire-frame by the existing methods. Several examples are provided

Effect of Cistanche deserticola Ma extract on memory of aged mice

Purpose: To assess the memory-enhancing effect of Cistanche deserticola Ma (Orobanchaceae) extract (CDME) on normal aged mice.Methods: An open-field test was used to study the effects of various doses of CDME on mouse locomotive activity. The mice were sacrificed following the locomotor test and the brain dissected to investigate the effects of CDME on catalase (CAT) and acetyl cholinesterase (AChE) activities in mouse brain tissue.Results: Compared with the control aged group, CDME (400 mg/kg) significantly reduced the total distance traveled (3312.5 ± 119.3 cm, p < 0.05), increased brain CAT activity (107.6 ± 11.8U/mg pro, p < 0.05), and inhibited brain AChE activity (0.89 ± 0.13 U/mg pro, p < 0.05) in CDME-exposed mice.Conclusion: The results show that CDME improves memory function in mice, probably by increasing the activity of CAT and decreasing AChE activity.Keywords: Cistanche deserticola Ma, Memory function, Catalase, Acetyl cholinesterase, Open-field tes

Fish species-specific TRIM gene FTRCA1 negatively regulates interferon response through attenuating IRF7 transcription

In mammals and fish, emerging evidence highlights that TRIM family members play important roles in the interferon (IFN) antiviral immune response. Fish TRIM family has undergone an unprecedented expansion leading to generation of finTRIM subfamily, which is exclusively specific to fish. Our recent results have shown that FTRCA1 (finTRIM C. auratus 1) is likely a fish species-specific finTRIM member in crucian carp C. auratus and acts as a negative modulator to downregulate fish IFN response by autophage-lysosomal degradation of protein kinase TBK1. In the present study, we found that FTRCA1 also impedes the activation of crucian carp IFN promoter by IRF7 but not by IRF3. Mechanistically, FTRCA1 attenuates IRF7 transcription levels likely due to enhanced decay of IRF7 mRNA, leading to reduced IRF7 protein levels and subsequently reduced fish IFN expression. E3 ligase activity is required for FTRCA1 to negatively regulate IRF7-mediated IFN response, because ligase-inactive mutants and the RING-deleted mutant of FTRCA1 lose the ability to block the activation of crucian carp IFN promoter by IRF7. These results together indicate that FTRCA1 is a multifaceted modulator to target different signaling factors for shaping fish IFN response in crucian carp.</p

Dynamic comparison between Daan real-time PCR and Cobas TaqMan for quantification of HBV DNA levels in patients with CHB

BACKGROUND: Hepatitis B virus (HBV) DNA levels are crucial for managing chronic hepatitis B (CHB). It was unclear whether Daan real-time polymerase chain reaction test (Daan test) or COBAS TaqMan HBV DNA Test (Cobas TaqMan) was superior in measuring different HBV DNA levels in clinical specimens. METHODS: We enrolled 67 treatment-naïve, HBV surface antigen-positive CHB patients (high baseline viral levels) who received either lamivudine/adefovir or entecavir. Serum samples were tested at baseline and treatment week 24 using the Daan test and Cobas TaqMan. RESULTS: In the 67-baseline samples, the HBV DNA levels with the Cobas TaqMan (7.90 ± 0.73 log(10) IU/mL) were significantly greater than those of the Daan test (7.11 ± 0.44 log(10) IU/mL; P < 0.001). Of the 67 24-week samples (low viral levels), the Cobas TaqMan detected 59 (88.1%; 8 undetected); the Daan test detected 33 (49.3%; 34 undetected; P < 0.001). The Cobas TaqMan detected HBV DNA in 26 of 34 samples undetectable by the Daan test (range, 1.4–3.7 log(10) IU/mL) or 38% of samples (26/67). The reductions in viral load after 24 weeks of oral antiviral treatment in the 33 samples that were positive for both the Daan test and the Cobas TaqMan test were significantly different (3.59 ± 1.11 log(10) IU/mL versus 4.87 ± 1.58 log(10) IU/mL, respectively; P = 0.001). Spearman correlation analysis showed positive correlation between results from two tests (r(p) = 0.602,P<0.001). The HBV genotypes and the anti-viral treatment did not affect the measurements of the HBV DNA by the Daan assay and the Cobas Taqman assay. CONCLUSION: The Cobas Taqman was more sensitive at low viral loads than the Daan test and the change from complete to partial virological response could affect clinical decisions. The Cobas Taqman may be more appropriate for detection of HBV DNA levels

An miR-200 Cluster on Chromosome 23 Regulates Sperm Motility in Zebrafish

Besides its well-documented roles in cell proliferation, apoptosis, and carcinogenesis, the function of the p53-microRNA axis has been recently revealed in the reproductive system. Recent studies indicated that miR-200 family members are dysregulated in nonobstructive azoospermia patients, whereas their functions remain poorly documented. The aim of this study was to investigate the function of the miR-200 family on zebrafish testis development and sperm activity. There was no substantial difference in testis morphology and histology between wild-type (WT) and knockout zebrafish with deletion of miR-200 cluster on chromosome 6 (chr6-miR-200-KO) or on chromosome 23 (chr23-miR-200-KO). Interestingly, compared with WT zebrafish, the chr6-miR-200-KO zebrafish had no difference on sperm motility, whereas chr23-miR-200-KO zebrafish showed significantly improved sperm motility. Consistently, ectopic expression of miR-429a, miR-200a, and miR-200b, which are located in the miR-200 cluster on chromosome 23, significantly reduced motility traits of sperm. Several sperm motility-related genes, such as amh, wt1a, and srd5a2b have been confirmed as direct targets of miR-200s on chr23. 17a-ethynylestradiol (EE2) exposure resulted in upregulated expression of p53 and miR-429a in testis and impairment of sperm motility. Strikingly, in p53 mutant zebrafish testis, the expression levels of miR-200s on chr23 were significantly reduced and accompanied by a stimulation of sperm motility. Moreover, the upregulation of miR-429a associated with EE2 treatment was abolished in testis with p53 mutation. And the impairment of sperm activity by EE2 treatment was also eliminated when p53 was mutated. Together, our results reveal that miR-200 cluster on chromosome 23 controls sperm motility in a p53-dependent manner.</p

Complete genome sequence and architecture of crucian carp Carassius auratus herpesvirus (CaHV)

Crucian carp Carassius auratus herpesvirus (CaHV) was isolated from diseased crucian carp with acute gill hemorrhages and high mortality. The CaHV genome was sequenced and analyzed. The data showed that it consists of 275,348 bp and contains 150 predicted ORFs. The architecture of the CaHV genome differs from those of four cyprinid herpesviruses (CyHV1, CyHV2, SY-C1, CyHV3), with insertions, deletions and the absence of a terminal direct repeat. Phylogenetic analysis of the DNA polymerase sequences of 17 strains of Herpesvirales members, and the concatenated 12 core ORFs from 10 strains of alloherpesviruses showed that CaHV clustered together with members of the genus Cyprinivirus, family Alloherpesviridae.</p

Rethinking Scale Imbalance in Semi-supervised Object Detection for Aerial Images

This paper focuses on the scale imbalance problem of semi-supervised object detection(SSOD) in aerial images. Compared to natural images, objects in aerial images show smaller sizes and larger quantities per image, increasing the difficulty of manual annotation. Meanwhile, the advanced SSOD technique can train superior detectors by leveraging limited labeled data and massive unlabeled data, saving annotation costs. However, as an understudied task in aerial images, SSOD suffers from a drastic performance drop when facing a large proportion of small objects. By analyzing the predictions between small and large objects, we identify three imbalance issues caused by the scale bias, i.e., pseudo-label imbalance, label assignment imbalance, and negative learning imbalance. To tackle these issues, we propose a novel Scale-discriminative Semi-Supervised Object Detection (S^3OD) learning pipeline for aerial images. In our S^3OD, three key components, Size-aware Adaptive Thresholding (SAT), Size-rebalanced Label Assignment (SLA), and Teacher-guided Negative Learning (TNL), are proposed to warrant scale unbiased learning. Specifically, SAT adaptively selects appropriate thresholds to filter pseudo-labels for objects at different scales. SLA balances positive samples of objects at different scales through resampling and reweighting. TNL alleviates the imbalance in negative samples by leveraging information generated by a teacher model. Extensive experiments conducted on the DOTA-v1.5 benchmark demonstrate the superiority of our proposed methods over state-of-the-art competitors. Codes will be released soon