Four main longwall panel systems are used in China: conventional longwall top coal caving (CLTCC), multi-slice longwall mining (MLM), high-seam longwall mining (HSLM), and longwall mining with split-level gateroads (LMSG). Theoretical analyses and physical modelling studies were carried out to investigate the interaction between vertical stress distribution within the goaf and surrounding rock mass in these systems. These studies were supported by numerical analyses and validated by field observation. The difficulty in numerical analysis for longwalls lies in goaf modelling, and research on this is rare. Reasonableness and correctness of numerical modelling is highly dependent on goaf behaviour. A complete and detailed numerical model of stress distribution within the goaf and surrounding rock mass is presented in this paper. A double-yield constitutive model, which is best fitted by Salamon's model that was obtained through laboratory tests, is used to simulate the goaf. The angle of break obtained through physical modelling was also incorporated into numerical modelling, which is closer to practice. The modelling shows that: (1) the more load the goaf bears, the less the abutment pressure and vice versa; (2) the abutment pressure, stress concentration factor, and yield zones would be larger without considering goaf behaviour; (3) goaf pressures in the curved section employing HSLM and LMSG are larger than in MLM and CLTCC; (4) when one slice is being extracted in MLM, the goaf pressure is greater than with any other methods, and the high-stress zone and yield zone are smaller; (5) the goaf edge is the most destressed zone in the entire panel system of the four mining methods. Field observation shows that the intake entry in LMSG has a favorable stress environment. Ground control problems such as severe deformation and bursts in the entry are therefore minimized, which in turn validates the theoretical and modelling analyses.

ABSTRACT Objective: It is agreed that methimazole (MMI) can be administered to induce hypothyroidism. However, there are conflicting data about its effect on thyroid function and development in rats through different administrations. In the present study, we established and compared differences of the rat hypothyroid model induced by MMI added to drinking water or given through an intragastric tube. Methods: Sixty-four male Wistar rats were randomly divided into seven groups. Methimazole was added to the drinking water (0.025%, 0.04% or 0.1% wt/vol), or through intragastric gavage (5 mg/100 g body weight (bw) or 8 mg/100 g bw) one time each day for 21 days. The rats were weighed every seven days. Blood samples were taken in order to detect the concentrations of serum triiodothyronine (T3), thyroxine (T4) and thyrotropin (TSH) at the end of the experiments. Results: Our results indicate that the effect of methimazole on a rat's thyroid function and body weight is similar in both the group given 0.1% concentration in drinking water and the group which received 8 mg/100 g bw once daily through the intragastric tube. Also, a similar effect was observed in the 0.025%, 0.04% and 5 mg/100 g bw groups. Conclusion: These findings suggest that a relationship between the concentration of MMI by oral administration and the dose of it through intragastric administration could exist, and may contribute to inducing hypothyroidism in rats.

RESUMEN Objetivo: Existe acuerdo en cuando a que el metimazol (MMI) puede ser administrado para inducir hipotiroidismo. Sin embargo, hay datos contradictorios en relación con su efecto sobre la función tiroidea y el desarrollo en ratas a través de diferentes administraciones. En el estudio actual, establecimos y comparamos las diferencias del modelo de hipotiroidismo en ratas. El hipotiroidismo es inducido añadiendo MMI al agua de beber, o suministrándolo a través de un tubo intragástrico. Métodos: Sesenta y cuatro ratas Wistar machos fueron divididas aleatoriamente en siete grupos. El metimazol fue añadido al agua de beber (0.025%, 0,04% ó 0.1% p/v), o suministrado mediante sonda intragástrica (5 mg/100 g de peso corporal (pc) ó 8 mg/100 g pc) una vez cada día por 21 días. Las ratas se pesaron cada 7 días. Se tomaron muestras de sangre para detectar las concentraciones de triyodotironina (T3), tiroxina (T4) y tirotropina (TSH) en suero al final de los experimentos. Resultados: Nuestros resultados indican que el efecto del metimazol sobre la función de la tiroides y el peso corporal de una rata es similar tanto en el grupo que recibió una concentración de 0.1% en el agua de beber como en el grupo que recibió 8 mg/100 g pc una vez al día a través de un tubo intragástrico. También se observó un efecto similar en los grupos de 0.025%, 0.04% y 5 mg/100 g pc. Conclusión: Estos resultados sugieren que podría existir una relación entre la concentración de MMI mediante administración oral y la dosis de la misma a través de administración intragástrica, lo cual puede contribuir a inducir hipotiroidismo en ratas.

Pancreatic ductal adenocarcinoma (PDAC) has a poor 5-year survival rate of 5%. Biomarkers for the early detection of pancreatic cancer are urgently needed. Transforming growth factor-beta1 (TGF-β1) is elevated in the tissues and plasma of patients with PDAC. However, no studies systemically report prognostic significance of plasma TGF-β1 levels in PDAC. In the present study, we assessed the prognostic significance of serum TGF-β levels in patients with PDAC. TGF-β levels were determined in serum from 146 PDAC patients, and 58 patients with benign pancreatic conditions. Regression models were used to correlate TGF-β levels to gender, age, stage, class, and metastasis. Survival analyses were performed using multivariate Cox models. Serum levels of TGF-β1 distinguished PDAC from benign pancreatic conditions (P<0.001) and healthy control subjects (P<0.001). Serum levels of TGF-β also distinguished tumor stage (P=0.002) and lymph node metastasis (P=0.001). High serum levels of TGF-β1 were significantly correlated with reduced patient survival. Multivariate analysis revealed that TGF-β1, lymph node metastasis and tumor stage were independent factors for PDAC survival. Our results indicate that serum TGF-β1 may be used as a potential prognostic marker for PDAC.

Angiogenesis and lymphangiogenesis are thought to play a role in the pathogenesis of inflammatory bowel diseases (IBD). However, it is not understood if inflammatory lymphangiogenesis is a pathological consequence or a productive attempt to resolve the inflammation. This study investigated the effect of lymphangiogenesis on intestinal inflammation by overexpressing a lymphangiogenesis factor, vascular endothelial growth factor-C (VEGF-C), in a mouse model of acute colitis. Forty eight-week-old female C57BL/6 mice were treated with recombinant adenovirus overexpressing VEGF-C or with recombinant VEGF-C156S protein. Acute colitis was then established by exposing the mice to 5% dextran sodium sulfate (DSS) for 7 days. Mice were evaluated for disease activity index (DAI), colonic inflammatory changes, colon edema, microvessel density, lymphatic vessel density (LVD), and VEGFR-3mRNA expression in colon tissue. When acute colitis was induced in mice overexpressing VEGF-C, there was a significant increase in colonic epithelial damage, inflammatory edema, microvessel density, and neutrophil infiltration compared to control mice. These mice also exhibited increased lymphatic vessel density (73.0±3.9 vs 38.2±1.9, P<0.001) and lymphatic vessel size (1974.6±104.3 vs 1639.0±91.5, P<0.001) compared to control mice. Additionally, the expression of VEGFR-3 mRNA was significantly upregulated in VEGF-C156S mice compared to DSS-treated mice after induction of colitis (42.0±1.4 vs 3.5±0.4, P<0.001). Stimulation of lymphangiogenesis by VEGF-C during acute colitis promoted inflammatory lymphangiogenesis in the colon and aggravated intestinal inflammation. Inflammatory lymphangiogenesis may have pleiotropic effects at different stages of IBD.

ABSTRACT Acute aortic dissection is a rare but potentially fatal disease. The early recognition of this disease is important for timely treatment. Some signs and symptoms, such as past history of hypertension, tearing pain and pulselessness, can provide valuable clues to the diagnosis of this disease. In this case study, the mechanism of a seagull murmur from aortic dissection is first described. This information is potentially useful for the differential diagnosis of dissection.

RESUMEN La disección aórtica aguda es una enfermedad rara pero potencialmente fatal. El reconocimiento temprano de esta enfermedad es importante para el tratamiento oportuno. Algunos signos y síntomas, tales como antecedentes de hipertensión, dolor desgarrador, y falta de pulso, pueden proporcionar pistas valiosas para el diagnóstico de esta enfermedad. En este caso, primero se describe el mecanismo de un soplo de gaviota de la disección aórtica. Esta información es potencialmente útil para el diagnóstico diferencial de la disección.

This study was designed to investigate the effect of curcumin (diferuloylmethane) on the proliferation and apoptosis of hepatic stellate cells (HSC). The cell line HSC-T6 (1.25 x 10(5) cells/mL) was incubated with curcumin and HSC proliferation was detected by a methyl thiazolyl tetrazolium colorimetric assay. HSC apoptosis was detected by flow cytometry, transmission electron microscope and agarose gel electrophoresis. HSC proliferation was significantly inhibited in a concentration-dependent manner (10.6 to 63.5%) after incubation with 20-100 μM curcumin, compared with a control group. At 20, 40, and 60 μM, after 24 h of incubation, curcumin was associated with a significant increase in the number of HSC in the G2/M phase, and a significant decrease in cell numbers in the S phase (P < 0.05). At these concentrations, curcumin was also associated with an increase in the apoptosis index of 15.3 ± 1.9, 26.7 ± 2.8, and 37.6 ± 4.4%, respectively, compared to control (1.9 ± 0.6%, P < 0.01). At 40 μM, the curcumin-induced apoptosis index at 12, 24, 36, and 48 h of incubation was 12.0 ± 2.4, 26.7 ± 3.5, 33.8 ± 1.8, and 49.3 ± 1.6%, respectively (P < 0.01). In conclusion, curcumin inhibits the in vitro proliferation of HSCs in the G2/M phase of the cell cycle and also induces apoptosis in a concentration- and time-dependent manner. The in vivo effect of curcumin on HSCs requires further investigation.