Continuous cold rubidium atomic beam with enhanced flux and tunable velocity.

We present a cold atomic beam source based on a two-dimensional (2D)+ magneto-optical trap (MOT), capable of generating a continuous cold beam of 87Rb atoms with a flux up to 4.3 × 109 s-1, a mean velocity of 10.96(2.20) m/s, and a transverse temperature of 16.90(1.56) µK. Investigating the influence of high cooling laser intensity, we observe a significant population loss of atoms to hyperfine-level dark states. To account for this, we employ a multiple hyperfine level model to calculate the cooling efficiency associated with the population in dark states, subsequently modifying the scattering force. Simulations of beam flux at different cooling and repumping laser intensities using the modified scattering force are in agreement with experimental results. Optimizing repumping and cooling intensities enhances the flux by 50%. The influence of phase modulation on both the pushing and cooling lasers is experimentally studied, revealing that the mean velocity of cold atoms can be tuned from 9.5 m/s to 14.6 m/s with a phase-modulated pushing laser. The versatility of this continuous beam source, featuring high flux, controlled velocity, and narrow transverse temperature, renders it valuable for applications in atom interferometers and clocks, ultimately enhancing bandwidth, sensitivity, and signal contrast in these devices.

Rapid Generation of Recombinant Flaviviruses Using Circular Polymerase Extension Reaction.

The genus Flavivirus is a group of arthropod-borne single-stranded RNA viruses, which includes important human and animal pathogens such as Japanese encephalitis virus (JEV), Zika virus (ZIKV), Dengue virus (DENV), yellow fever virus (YFV), West Nile virus (WNV), and Tick-borne encephalitis virus (TBEV). Reverse genetics has been a useful tool for understanding biological properties and the pathogenesis of flaviviruses. However, the conventional construction of full-length infectious clones for flavivirus is time-consuming and difficult due to the toxicity of the flavivirus genome to E. coli. Herein, we applied a simple, rapid, and bacterium-free circular polymerase extension reaction (CPER) method to synthesize recombinant flaviviruses in vertebrate cells as well as insect cells. We started with the de novo synthesis of the JEV vaccine strain SA-14-14-2 in Vero cells using CPER, and then modified the CPER method to recover insect-specific flaviviruses (ISFs) in mosquito C6/36 cells. Chimeric Zika virus (ChinZIKV) based on the Chaoyang virus (CYV) backbone and the Culex flavivirus reporter virus expressing green fluorescent protein (CxFV-GFP) were subsequently rescued in C6/36 cells. CPER is a simple method for the rapid generation of flaviviruses and other potential RNA viruses. A CPER-based recovery system for flaviviruses of different host ranges was established, which would facilitate the development of countermeasures against flavivirus outbreaks in the future.

Homocysteine inhibits the viability and migration ability of human umbilical vein endothelial cells by downregulating the expression of vascular endothelial growth factor.

The current study aimed to explore the effect of homocysteine (Hcy) on the viability and migration ability of human umbilical vein endothelial cells (HUVECs), as well as to examine the underlying mechanism. The association between the expression level of Hcy and lower extremity deep vein thrombosis (DVT) was detected in clinical samples collected from patients. In addition, the effect of Hcy on the viability and migration ability of HUVECs was detected by cell counting kit-8 and Transwell assays, respectively, while vascular endothelial growth factor (VEGF) expression was measured in order to verify the effect of Hcy on VEGF. The results indicated that the serum Hcy levels in DVT patients were significantly increased. In vitro experiments also confirmed that Hcy was able to significantly inhibit the viability and migration ability of HUVECs, and downregulate the expression of VEGF in these cells. Furthermore, the inhibitory effect of Hcy on HUVEC viability and migration ability was achieved by downregulating the expression of VEGF using small interfering RNA transfection. In conclusion, Hcy inhibited the viability and migration ability of HUVECs by downregulating the expression of VEGF. This may underlie the high incidence of DVT in patients with hyperhomocysteinemia.

Tuberculous abdominal cocoon mimicking peritoneal carcinomatosis.

Background: Tuberculous abdominal cocoon is an uncommon manifestation of abdominal tuberculosis. As a rare clinical entity, it is often encountered unexpectedly in patients with small intestinal obstruction. Here we presented a rare case of tuberculous abdominal cocoon which was suspected to be peritoneal carcinomatosis and was finally diagnosed by laparoscopy. Case presentation: A 47-year-old man developed small intestinal obstruction and massive ascites that did not resolve with conservative management. Surgical exploration revealed a fibrous sheath covering the small-bowel, and pathologic assessment of biopsies confirmed intra-abdominal tuberculous infection. After antituberculosis therapy, the ascites has greatly diminished and the patient was functioning normally. Conclusion: Preoperative diagnosis of tuberculous abdominal cocoon is a true challenge. Early diagnostic peritoneal biopsy should be recommended and surgery is usually unnecessary if definitive diagnosis can be made.

Overexpression of SMYD3 Is Predictive of Unfavorable Prognosis in Hepatocellular Carcinoma.

SET and MYND domain-containing protein 3 (SMYD3) is a kind of histone lysine methyltransferase, responsible for transcriptional activation as a member of an RNA polymerase complex. The ectopic expression of SMYD3 is proved to promote the progress of many kinds of cancers. In hepatocellular carcinoma (HCC), SMYD3 was demonstrated to promote the proliferation and metastasis of HCC cell lines, but the clinical significance of SMYD3 has not been elucidated. In the present study, we detected the expression of SMYD3 in 100 HCC tissues with immunohistochemistry and divided these tissue specimens into high-expression group and low-expression group according to the immunohistochemical score of SMYD3. Importantly, the intensity of SMYD3 immunoreactivity was significantly stronger in HCC tissues than that in adjacent normal tissues. Moreover, high expression levels of SMYD3 were significantly associated with larger tumor size (P = 0.043), suggesting that SMYD3 could promote the proliferation of HCC. Moreover, patients with positive hepatitis B virus infection had higher expression levels of SMYD3 (P = 0.013). With univariate and multivariate analysis, we explored the prognostic significance of SMYD3 in HCC. As a result, high expression levels of SMYD3 were significantly correlated to the poorer clinical outcome of HCC patients (P = 0.009) and were identified as an independent risk factor of HCC for predicting the unfavorable prognosis. In conclusion, overexpression of SMYD3 is an independent prognostic risk of unfavorable prognosis of HCC. We propose that the anti-SMYD3 therapy may be a potential approach to treat HCC.

Endocan-expressing microvessel density as a prognostic factor for survival in human gastric cancer.

AIM: To investigate the expression of endocan in tumour vessels and the relationships between endocan and the expression of vascular endothelial growth factor (VEGF) and prognosis in gastric cancer. METHODS: This study included 142 patients with confirmed gastric cancer in a single cancer centre between 2008 and 2009. Clinicopathologic features were determined, and an immunohistochemical analysis of endocan-expressing microvessel density (MVD) (endocan-MVD), VEGF and vascular endothelial growth factor receptor 2 (VEGFR2) was performed. Potential relationships between endocan-MVD and clinicopathological variables were assessed using a Student's t-test or an analysis of variance test. Spearman's rank correlation was applied to evaluate the relationship between endocan-MVD and the expression of VEGF/VEGFR2. Long-term survival of these patients was analysed using univariate and multivariate analyses. RESULTS: Positive staining of endocan was observed in most of the gastric cancer tissues (108/142) and in fewer of the normal gastric tissues. Endocan-MVD was not associated with gender or histological type (P > 0.05), while endocan-MVD was associated with tumour size, Borrmann type, tumour differentiation, tumour invasion, lymph node metastasis and TNM stage (P < 0.05). According to the Spearman's rank correlation analysis, endocan-MVD had a positive correlation with VEGF (r = 0.167, P = 0.047) and VEGFR2 (r = 0.410, P = 0.000). The univariate analysis with a log-rank test indicated that the patients with a high level of endocan-MVD had a significantly poorer overall survival rate than those with a low level of endocan-MVD (17.9% vs 64.0%, P = 0.000). The multivariate analysis showed that a high level of endocan-MVD was a valuable prognostic factor. CONCLUSION: Endocan-MVD significantly correlates with the expression of VEGF and VEGFR2 and is a valuable prognostic factor for survival in human gastric cancer.

Calcified Cystic Lesion of the Pancreas.

Pancreatic cystic lesion is a relatively uncommon condition with an estimated prevalence of 2 % in the general population. In the past two decades, there has been a dramatic increase in the prevalence of pancreatic cystic lesions because of the widespread use of high-resolution imaging, as well as the aging of the population. Pancreatic cystic lesions cover a wide spectrum of pathology and can range from obviously benign to borderline malignant potential lesions to overt malignancy. Though the presence of mural nodules, septa-like structures, or calcification on imaging examination contributes to the differential diagnosis, preoperatively determining the biological nature of these cystic lesions is sometimes challenging. In this paper, we report a rare case of pancreatic cystic lesion with an egg-shell like calcification. Complete resection was performed and histological examination confirmed the diagnosis of calcified pancreatic pseudocyst.

[Separation and preconcentration by extraction and anti-extraction-determination of trace Te in complex geological samples by hydride generation atomic fluorescence spectrometry].

A method for the determination of trace Te in the complex geological samples by hydride generation atomic fluorescence spectrometry using MIBK as extraction reagent was developed. The extraction ability of Te (IV) in the HCl-NaBr-MIBK system and the anti-extraction behavior of Te (IV) in the HCl-KMnO4-MIBK system were studied. Under the optimum extraction condition of 3.6 mol x L(-1) HCl-100 g x L(-1) NaBr, Te (IV) was extracted completely by MIBK, Te (IV) in the MIBK phase was oxidized to Te (VI) with HCl-KMnO4, Te (VI) in the MIBK phase was anti-extracted using water, then the interference elements such as Au, Ag, Pt, Pd, Cu, Pb, Co, Ni, Cd, As, Sb, Bi, Hg, Tl and Se for the determination of Te by hydride generation atomic fluorescence spectrometry were eliminated successfully. The detection limit of Te was 1.14 x 10(-4) microg(-1), and the relative standard deviations of Te was 6.84%. The method was applied to complicated geological samples.