2-(Hydrazonomethyl)phenol

The conformation of the title compound, C7H8N2O, is stabilized by an intra­molecular O—H⋯N hydrogen bond. The crystal structure shows inter­molecular N—H⋯O hydrogen bonds

The Photometric System of Tsinghua-NAOC 80-cm Telescope at NAOC Xinglong Observatory

Tsinghua-NAOC (National Astronomical Observatories of China) Telescope (hereafter, TNT) is an 80-cm Cassegrain reflecting telescope located at Xinglong bservatory of NAOC, with main scientific goals of monitoring various transients in the universe such as supernovae, gamma-ray bursts, novae, variable stars, and active galactic nuclei. We present in this paper a systematic test and analysis of the photometric performance of this telescope. Based on the calibration observations on twelve photometric nights, spanning the period from year 2004 to year 2012, we derived an accurate transformation relationship between the instrumental $ubvri$ magnitudes and standard Johnson $UBV$ and Cousins $RI$ magnitudes. In particular, the color terms and the extinction coefficients of different passbands are well determined. With these data, we also obtained the limiting magnitudes and the photometric precision of TNT. It is worthwhile to point out that the sky background at Xinglong Observatory may become gradually worse over the period from year 2005 to year 2012 (e.g., $\sim$21.4 mag vs. $\sim$20.1 mag in the V band).Comment: 12 pages,9 figures, accepted by RA

Methyl (E)-3-(2-bromo-4,5-dimeth­oxy­benzyl­idene)dithio­carbazate

The title compound, C11H13BrN2O2S2, was obtained from the condensation reaction of methyl dithio­carbazate and 2-bromo-4,5-dimeth­oxy­benzaldehyde. In the mol­ecule, the benzene ring and dithio­carbazate fragment are located on opposite sides of the C=N bond, showing an E conformation. The dithio­carbazate fragment is approximately planar (r.m.s deviation = 0.0281 Å) and the mean plane is oriented at a dihedral angle of 11.38 (15)° with respect to the benzene ring. In the crystal, pairs of N—H⋯S hydrogen bonds link the mol­ecules into centrosymmetric dimers

Clinical analysis of 1 case of solitary brain metastases misdiagnosed as cerebral infarction

目的  通过报告1例误诊为脑梗死的单发性脑转移瘤患者的诊断过程，总结单发性脑转移瘤的临床、影像学特征及诊断治疗方法。方法  回顾性分析1例单发性脑转移瘤患者的诊断过程，并复习有关文献。结果  脑转移瘤常多发，单发者仅占25%，发病年龄以40～60岁多见，原发病灶以肺最常见。脑转移瘤常位于脑叶灰白质交界处，不同部位的肿瘤可出现不同的临床表现，影像学上常表现为“小病灶、大水肿”，与颅内原发肿瘤不易区分，头颅CT或 MRI增强检查并查到其他部位的原发肿瘤病灶后可确定诊断。目前主张单发性脑转移瘤应进行手术切除，术后辅以立体定向放射治疗和全脑放射治疗。结论  15%的脑转移瘤患者既往无肿瘤病史，因此诊断脑瘤后须在身体其他部位查找有无原发病灶，避免误诊、漏诊。对于中老年肺癌或其他恶性肿瘤患者，无论有无中枢神经系统症状，均应积极进行头颅CT甚至MRI检查，以发现较小的早期脑转移瘤病灶。对于易患肺癌人群，应该每年体检，进行胸部X线检查或低剂量CT筛查，以便早期发现肺癌病灶，早期治疗，防止肿瘤转移。Objective: To report 1 case was misdiagnosed as cerebral infarction solitary brain metastases (SBM) in patients with diagnosis process, and to summarize the clinical and imaging features of the SBM and its treatment. Methods: To retrospectively analyze the diagnostic process of 1 case of SBM patients, and to have literature review. Results: Patients with solitary and multiple brain metastases accounted for only 25%, the onset age was 40 ~ 60 years old, and the most common primary lesion is in lung. Brain metastases are often on the border, in between lobes grey matter. Different parts of the tumors can present different clinical manifestations. The diagnostic imaging is often shown as "small lesions, large edema", and intracranial primary tumor is not easy to distinguish, Head CT or MRI examination of tumors in other parts could confirm the diagnosis. Now that SBM should undergo surgery resection, postoperative supplemented by stereotactic radiotherapy and whole brain radiotherapy. Conclusions: 15% of the patients with brain metastases haven’t got previous medical history, the doctor is therefore must look for presence of primary lesions in other parts of the body for accurate diagnosis, to avoid the misdiagnosis and missed diagnosis. Middle-aged and elderly patients with lung cancer or other malignant tumor, regardless of the presence of the central nervous system symptoms, should carry on the head CT or MRI examination, and find smaller early brain metastatic lesions. People who are susceptible to lung cancer should have annual physical examination, chest X-ray or low dose CT screening for early detection of lung cancer lesions, early treatment and prevention of tumor metastasi

Cross-reaction mediated by distinct key amino acid combinations in the complementary-determining region (CDR) of a monoclonal antibody

In immunology, cross-reaction between antigens and antibodies are commonly observed. Prior research has shown that various monoclonal antibodies (mAbs) can recognize a broad spectrum of epitopes related to influenza viruses. However, existing theories on cross-reactions fall short in explaining the phenomena observed. This study explored the interaction characteristics of H1-74 mAb with three peptides: two natural peptides, LVLWGIHHP and LPFQNI, derived from the hemagglutinin (HA) antigen of the H1N1 influenza virus, and one synthetic peptide, WPFQNY. Our findings indicate that the complementarity-determining region (CDR) of H1-74 mAb comprised five antigen-binding sites, containing eight key amino acid residues from the light chain variable region and 16 from the heavy chain variable region. These critical residues formed distinct hydrophobic or hydrophilic clusters and functional groups within the binding sites, facilitating interaction with antigen epitopes through hydrogen bonding, salt bridge formation, and π–π stacking. The study revealed that the formation of the antibody molecule led to the creation of binding groups and small units in the CDR, allowing the antibody to attach to a variety of antigen epitopes through diverse combinations of these small units and functional groups. This unique ability of the antibody to bind with antigen epitopes provides a new molecular basis for explaining the phenomenon of antibody cross-reaction

NNMap: A method to construct a good embedding for nearest neighbor classification

a b s t r a c t This paper aims to deal with the practical shortages of nearest neighbor classifier. We define a quantitative criterion of embedding quality assessment for nearest neighbor classification, and present a method called NNMap to construct a good embedding. Furthermore, an efficient distance is obtained in the embedded vector space, which could speed up nearest neighbor classification. The quantitative quality criterion is proposed as a local structure descriptor of sample data distribution. Embedding quality corresponds to the quality of the local structure. In the framework of NNMap, one-dimension embeddings act as weak classifiers with pseudo-losses defined on the amount of the local structure preserved by the embedding. Based on this property, the NNMap method reduces the problem of embedding construction to the classical boosting problem. An important property of NNMap is that the embedding optimization criterion is appropriate for both vector and non-vector data, and equally valid in both metric and non-metric spaces. The effectiveness of the new method is demonstrated by experiments conducted on the MNIST handwritten dataset, the CMU PIE face images dataset and the datasets from UCI machine learning repository

Characterization of a New Cyclohexylamine Oxidase From Acinetobacter sp. YT-02

Cyclohexylamine (CHAM) is widely used in various industries, but it is harmful to human beings and the environment. Acinetobacter sp. YT-02 can degrade CHAM via cyclohexanone as an intermediate. In this study, the cyclohexylamine oxidase (CHAO) gene from Acinetobacter sp. YT-02 was cloned. Amino acid sequence alignment indicated that the cyclohexylamine oxidase (CHAOYT–02) was 48% identical to its homolog from Brevibacterium oxydans IH-35A (CHAOIH–35). The enzyme was expressed in Escherichia coli BL21 (DE3), and purified to apparent homogeneity by Ni-affinity chromatography. The purified enzyme was proposed to be a dimer of molecular mass of approximately 91 kDa. The enzyme exhibited its maximum activity at 50°C and at pH 7.0. The enzyme was thermolabile as demonstrated by loss of important percentage of its maximal activity after 30 min incubation at 50°C. Metal ions Mg2+, Co2+, and K+ had certain inhibitory effect on the enzyme activity. The kinetic parameters Km and Vmax were 0.25 ± 0.02 mM and 4.3 ± 0.083 μM min−1, respectively. The biochemical properties, substrate specificities, and three-dimensional structures of CHAOYT–02 and CHAOIH–35 were compared. Our results are helpful to elucidate the mechanism of microbial degradation of CHAM in the strain YT-02. In addition, CHAOYT–02, as a potential biocatalyst, is promising in controlling CHAM pollution and deracemization of chiral amines

Investigation of the prevalence and clinical implications of ERBB2 exon 16 skipping mutations in Chinese pan-cancer patients

BackgroundAlthough rare, ERBB2 exon 16 skipping mutations (ERBB2ΔEx16) have been implicated in resistance to anti-HER2 and anti-EGFR targeted agents. Our study investigated the prevalence and clinical significance of ERBB2ΔEx16 in Chinese pan-cancer patients.MethodsWe retrospectively screened 40996 patients, spanning 19 cancer types, who had available genomic profiles acquired with DNA-based next-generation sequencing (NGS). We characterized the clinical and molecular features of the ERBB2ΔEx16-positive patients. Furthermore, we also analyzed a pan-cancer dataset from the Cancer Genome Atlas (TCGA; n=8705).ResultsA total of 22 patients were detected with ERBB2ΔEx16, resulting in an overall prevalence rate of 0.054% (22/40996). Of them, 16 patients had lung cancer (LC; 0.05%, 16/30890), five patients had gastric cancer (GC; 0.35%, 5/1448), and one patient had ovarian cancer (0.12%, 1/826). Among the 16 LC patients, ERBB2ΔEx16 was detected in four treatment-naïve EGFR/ALK-negative patients and 12 EGFR-positive patients after the onset of resistance to EGFR tyrosine kinase inhibitors (TKIs). The treatment-naïve patients harbored no LC-associated oncogenic drivers except ERBB2 amplification, suggesting a potential oncogenic role for ERBB2ΔEx16. Consistently, ERBB2ΔEx16+ patients from TCGA data also carried no known drivers despite various concurrent alterations. In the 12 EGFR TKI-resistant LC patients, relative variant frequencies for ERBB2ΔEx16 were lower than in untreated patients, suggesting ERBB2ΔEx16 as secondary alterations following TKI treatment and thereby implicating ERBB2ΔEx16 in mediating therapeutic resistance.ConclusionsOur study identified an overall ERBB2ΔEx16 prevalence rate of 0.054% and provided insights into the clinical implications of ERBB2ΔEx16 in Chinese pan-cancer patients

The impact of the atmospheric turbulence-development tendency on new particle formation : a common finding on three continents

A new mechanism of new particle formation (NPF) is investigated using comprehensive measurements of aerosol physicochemical quantities and meteorological variables made in three continents, including Beijing, China; the Southern Great Plains site in the USA; and SMEAR II Station in Hyytiala, Finland. Despite the considerably different emissions of chemical species among the sites, a common relationship was found between the characteristics of NPF and the stability intensity. The stability parameter (zeta = Z/L, where Z is the height above ground and L is the Monin-Obukhov length) is found to play an important role; it drops significantly before NPF as the atmosphere becomes more unstable, which may serve as an indicator of nucleation bursts. As the atmosphere becomes unstable, the NPF duration is closely related to the tendency for turbulence development, which influences the evolution of the condensation sink. Presumably, the unstable atmosphere may dilute pre-existing particles, effectively reducing the condensation sink, especially at coarse mode to foster nucleation. This new mechanism is confirmed by model simulations using a molecular dynamic model that mimics the impact of turbulence development on nucleation by inducing and intensifying homogeneous nucleation events.Peer reviewe