First-principles study of the temperature-induced band renormalization in thermoelectric filled skutterudites

Band structure characteristics, such as band gap and band dispersion, are fundamental properties of materials. Temperature can affect them because of lattice expansion and phonon-induced atomic vibrations. Here, we apply the recently developed electron-phonon renormalization method to study the temperature effect on the band structures of thermoelectric (TE) filled skutterudites BaCo4Sb12, BaFe4Sb12, and YbFe4Sb12 from first-principles. The results reveal that the band gap in BaCo4Sb12 drops slower with temperature compared with our previous study on CoSb3, where it considerably reduces from 0 K to 800 K for BaFe4Sb12 (∼0.222 eV) and YbFe4Sb12 (∼0.201 eV). Furthermore, the band dispersions near the band edges at the Γ-point in the three systems at high temperatures are similar to those at 0 K, and the electron energies have small linewidths, whereas the linewidths for energies near the Fermi level are large. The different phenomena are due to the different phonon vibration-induced electronic structure disorders, reflecting the strength of electron-phonon coupling. Band renormalization would further affect the TE properties of these filled skutterudites. Our work provides a deeper understanding of the temperature-dependent band structure in skutterudites.

[Silencing SIRT1 reduces 5-fluorouracil resistance of cholangiocarcinoma cells by inhibiting the FOXO1/Rab7 autophagy pathway]

OBJECTIVE

To investigate the mechanism by which SIRT1 silencing reduces 5-fluorouracil (5-FU) resistance of cholangiocarcinoma cells and the role of FOXO1/Rab7 autophagy pathway in mediating this effect.

METHODS

Human cholangiocarcinoma HCCC-9810 cells were treated with 50, 100, 150, and 200 μg/mL 5-FU to construct a 5-FU-resistant cell model, whose expressions of SIRT1, FOXO1 and Rab7 were detected with immunofluorescence assay, Western blotting and RTqPCR, and the expression levels of autophagy related proteins (Beclin1, LC3, and p62) were detected with Western blotting. The 5-FU resistant cells were transfected with a SIRT1 siRNA, and the changes in 5-Fu resistance and migration ability of the cells were evaluated using CCK-8 assay and wound healing assay; The changes in FOXO1 and Rab7 mRNA levels and protein expressions of SIRT1, FOXO1, Rab7, Beclin1, LC3 and P62 were detected with RT-qPCR and Western blotting.

RESULTS

Treatments with 5-FU at 50, 100, 150, and 200 μg/mL all inhibited the proliferation of HCCC-9810 cells. Immunofluorescence assay revealed significantly enhanced SIRT1 expression in 5-FU-resistant HCC-9810 cells, and Western blotting also showed significantly up-regulated protein expressions of SIRT1, Rab7, P62, FOXO1 and Beclin 1 (P < 0.001) and an increased LC3II/LC3I ratio in the cells (P < 0.001). The mRNA levels of SIRT1, Rab7 and FOXO1 were also up-regulated in 5-Fu-resistant cells (P < 0.05). SIRT1 silencing significantly attenuated 5-FU resistance and migration ability of HCCC-9810 cells, and obviously decreased the protein expressions of SIRT1, Rab7, P62, FOXO1 and Beclin1 and the LC3II/LC3I ratio as well (P < 0.001). FOXO1 and Rab7 mRNA levels were significantly decreased in 5-FU-resistant HCC-9810 cells after SIRT1 silencing (P < 0.05).

CONCLUSION

Silencing SIRT1 attenuates 5-FU resistance in HCC-9810 cells by inhibiting the activation of the FOXO1/Rab7 autophagy pathway.

A Critical Review of Machine Learning Techniques on Thermoelectric Materials

Thermoelectric (TE) materials can directly convert heat to electricity and vice versa and have broad application potential for solid-state power generation and refrigeration. Over the past few decades, efforts have been made to develop new TE materials with high performance. However, traditional experiments and simulations are expensive and time-consuming, limiting the development of new materials. Machine learning (ML) has been increasingly applied to study TE materials in recent years. This paper reviews the recent progress in ML-based TE material research. The application of ML in predicting and optimizing the properties of TE materials, including electrical and thermal transport properties and optimization of functional materials with targeted TE properties, is reviewed. Finally, future research directions are discussed.

Clinical characteristics of 14 pediatric mycoplasma pneumoniae pneumonia associated thrombosis: a retrospective study

OBJECTIVE

This study aimed to investigate the clinical characteristics and long-term prognosis of mycoplasma pneumoniae pneumonia (MPP)-associated thrombosis and to gain a better understanding of the diagnosis and treatment of the disease.

METHODS

The medical records of 14 children with MPP-associated thrombosis between January 2016 and April 2020 were retrospectively reviewed at the Tianjin Children's Hospital.

RESULTS

The ages of the patients ranged from 3 to 12 years old. Among the 14 cases, there were five cases of pulmonary embolism, two cases of cerebral infarction, one case of splenic infarction, one case of cardiac embolism, two cases of cardiac embolism with comorbid pulmonary embolism, one case of internal carotid artery and pulmonary embolism, one case of combined internal carotid artery and the cerebral infarction, and one case combined cardiac embolism and lower limb artery embolism. All cases had elevated D-dimer levels. After thrombolysis and anticoagulation therapy, three cases with cerebral embolism still suffered from neurological sequelae. In contrast, the remaining cases did not develop complications.

CONCLUSION

MPP-associated thrombosis can occur in any vessel of the body. Thrombosis-associated symptoms may be complex and non-specific. Elevated D-dimer levels in a child with refractory mycoplasma pneumoniae pneumonia should raise suspicion of thrombosis. The long-term prognosis of thrombosis was favorable after the timely administration of anticoagulant therapy.

Temperature-dependence of the band gap in the all-inorganic perovskite CsPbI3 from room to high temperatures

Understanding the micro-mechanism of the temperature dependence of the band gap in all-inorganic perovskites is of great significance for their optoelectronic and photovoltaic applications in various temperature environments. Herein, based on the recently developed electron-phonon renormalization method, the temperature-dependent band gaps of the optoelectronic perovskite CsPbI₃ are studied from 300 K to 750 K (including orthorhombic, tetragonal, and cubic phases). It is found that the temperature-induced structural fluctuation makes the structure of perovskites deviate from the 0 K one, and the corresponding renormalized band gap differs from that at 0 K, especially for the high-temperature cubic phase (e.g., ΔE_g is ∼177 meV at 600 K). However, within the temperature range of each CsPbI₃ phase, the band gap E_g is enlarged slightly with the increase of temperature (e.g., ΔE_g is ∼26 meV from 600 K to 750 K for the cubic phase), showing the insensitivity of the structural fluctuation effect to the temperature change. The reason is that the chemical characters of band edges are determined by PbI₃^-, and due to the strong correlation between Pb and I, the Pb-I bond lengths and Pb-I-Pb bond angles are almost unchanged as the temperature increases. Our work provides a fundamental understanding of the temperature-dependent band gaps in all-inorganic perovskites and shed light on the commercialization of perovskites.

Modulating the Graphitic Domains of Hard Carbons Derived from Mixed Pitch and Resin to Achieve High Rate and Stable Sodium Storage

Resin derived hard carbons (HCs) generally demonstrate remarkable electrochemical performance for both sodium ion batteries (SIBs) and potassium-ion batteries (KIBs), but their practical applications are hindered by their high price and high temperature pyrolysis (≈1500 °C). Herein, low-cost pitch is coated on the resin surface to compromise the cost, and meanwhile manipulate the microstructure at a relatively low pyrolysis temperature (1000 °C). HC-0.2P-1000 has a large number of short graphitic layer structures and a relatively large interlayer spacing of 0.3743 nm, as well as ≈1 nm sized nanopores suitable for sodium storage. Consequently, the as produced material demonstrates a superior reversible capacity (349.9 mAh g^-1 for SIBs and 321.9 mAh g^-1 for KIBs) and excellent rate performance (145.1 mAh g^-1 at 20 A g^-1 for SIBs, 48.5 mAh g^-1 at 20 A g^-1 for KIBs). Furthermore, when coupled with Na₃ V₂ (PO₄ )₃ as cathode, the full cell exhibits a high energy density of 251.1 Wh kg^-1 and excellent stability with a capacity retention of 73.3% after 450 cycles at 1 A g^-1 .

Fabrication of Iron Pyrite Thin Films and Photovoltaic Devices by Sulfurization in Electrodeposition Method

Iron pyrite is a cheap, stable, non-toxic, and earth-abundant material that has great potential in the field of photovoltaics. Electrochemical deposition is a low-cost method, which is also suitable for large-scale preparation of iron pyrite solar cells. In this work, we prepared iron pyrite films by electrochemical deposition with thiourea and explored the effect of sulfurization on the synthesis of high-quality iron pyrite films. Upon sulfurization, the amorphous precursor film becomes crystallized iron pyrite film. Optical and electrical characterization show that its band gap is 0.89 eV, and it is an n type semiconductor with a carrier concentration of 3.01 × 10¹⁹ cm^-3. The corresponding photovoltaic device shows light response. This work suggests that sulfurization is essential in the electrochemical preparation for fabricating pure iron pyrite films, and therefore for low-cost and large-scale production of iron pyrite solar cells.

Preparation and Application of Fluorine-Free Finishing Agent with Excellent Water Repellency for Cotton Fabric

Water repellent is an important functional finish for cotton fabric. However, cotton fabrics often have poor washing resistance and other performances after actual finishing. In this study, based on the structural characteristics of cotton fiber and durability of water repellent, a cross-linked amino long-chain alkyl polysiloxane (CAHPS) was first prepared, and then reacted with modified silica. Finally, a chemically bonded organic-inorganic nanohybrid cross-linked polysiloxane (rSiO2-CAHPS) was fabricated. Furthermore, the rSiO2-CAHPS was emulsified to obtain a durable fluorine-free water repellent. The water repellent finishing for cotton fabric was carried out by the pad-dry-cure process. After finishing, the cotton fabric had good resistance to conventional liquids and excellent washing resistance, and still maintained good water repellency after 30 rounds of soaping. Moreover, properties including air permeability, mechanical property and whiteness are hardly affected after finishing. SEM and XPS characterization show that a layer of dense silicon film is formed on the surface of cotton fabric by rSiO2-CAHPS water repellent. The existence of nanosilica can improve the surface roughness of cotton fibers. The synergistic effect of fiber matrix, nanoparticles and CAHPS endows the fabric with a micro/nano-multi-scale micro-rough structure, which improves the water repellency of cotton fabric after water repellent finishing.

Histopathological features of complete pathological response predict recurrence-free survival following neoadjuvant targeted therapy for metastatic melanoma

BACKGROUND

Recent clinical trials demonstrated the safety and efficacy of neoadjuvant dabrafenib and trametinib (DT) among patients with surgically resectable clinical stage III BRAFV600E/K mutant melanoma. Although patients achieving a complete pathological response (pCR) exhibited superior recurrence-free survival (RFS) versus those who did not, 30% of pCR patients relapsed. We sought to identify whether histopathological features of the pathological response further delineated risk of relapse.

METHODS

Surgical resection specimens from DT-treated patients in two phase 2 clinical trials were reviewed. Histopathological features, including relative amounts of viable tumour, necrosis, melanosis, and fibrosis (hyalinized or immature/proliferative) were assessed for associations with patient outcomes.

RESULTS

Fifty-nine patients underwent surgical resection following neoadjuvant DT. Patients achieving pCR (49%) had longer RFS compared with patients who did not (P = 0.005). Patients whose treated tumour showed any hyalinized fibrosis had longer RFS versus those without (P = 0.014), whereas necrosis (P = 0.012) and/or immature/proliferative fibrosis (P = 0.026) correlated with shorter RFS. Multivariable analyses showed absence of pCR or presence of immature fibrosis independently predicted shorter RFS. Among pCR patients, mature/hyalinized-type fibrosis correlated with improved RFS (P = 0.035).

CONCLUSIONS

The extent and composition of the pathological response following neoadjuvant DT in BRAFV600E/K mutant melanoma correlates with RFS, including pCR patients. These findings support the need for detailed histological analysis of specimens collected after neoadjuvant therapy.

Modelling the evolution trajectory of COVID-19 in Wuhan, China: experience and suggestions

OBJECTIVES

In December 2019, a novel coronavirus disease (COVID-19) emerged in Wuhan city, China, which has subsequently led to a global pandemic. At the time of writing, COVID-19 in Wuhan appears to be in the final phase and under control. However, many other countries, especially the US, Italy and Spain, are still in the early phases and dealing with increasing cases every day. Therefore, this article aims to summarise and share the experience of controlling the spread of COVID-19 in Wuhan and provide effective suggestions to enable other countries to save lives.

STUDY DESIGN

Data from the National Health Commission of China are used to investigate the evolution trajectory of COVID-19 in Wuhan and discuss the impacts of the intervention strategies.

METHODS

A four-stage modified Susceptible-Exposed-Infectious-Removed (SEIR) model is presented. This model considers many influencing factors, including chunyun (the Spring festival), sealing off the city and constructing the Fangcang shelter hospitals. In addition, a novel method is proposed to address the abnormal data on 12-13 February as a result of changing diagnostic criteria. Four different scenarios are considered to capture different intervention measures in practice. The exposed population in Wuhan who moved out before sealing off the city have also been identified, and an analysis on where they had gone was performed using the Baidu Migration Index.

RESULTS

The results demonstrate that the four-stage model was effective in forecasting the peak, size and duration of COVID-19. We found that the combined intervention measures are the only effective way to control the spread and not a single one of them can be omitted. We estimate that England will be another epicentre owing to its incorrect response at the initial stages of COVID-19. Fortunately, big data technology can help provide early warnings to new areas of the pandemic.

CONCLUSIONS

The four-stage SEIR model was effective in capturing the evolution trajectory of COVID-19. Based on the model analysis, several effective suggestions are proposed to prevent and control the pandemic for countries that are still in the initial phases.

Simplified colonic dialysis with hemodialysis solutions delays the progression of chronic kidney disease

BACKGROUND

The colon plays a vital role in the disposal of nitrogenous waste products. Therefore, the colon may provide a therapeutic target for managing chronic kidney disease (CKD).

AIM

To evaluate the efficacy of a simplified model of colonic dialysis with hemodialysis solutions (SCD) to delay the progression of stages 3-5 CKD.

DESIGN

Retrospective study.

METHODS

We retrospectively analyzed 178 stages 3-5 CKD patients who did or did not receive SCD (SCD group, n = 88; control group, n = 90). The follow-up was 36 months. The outcome of CKD progression was defined as a decrease in 50% or more in estimated glomerular filtration rate, starting hemodialysis or peritoneal dialysis or undergoing transplantation. The Kaplan-Meier analysis was used to compare CKD progression between SCD and control groups as well as between subgroups at different CKD stages. Cox proportional hazard models adjusted for patients' characteristics were used to examine the association between SCD and the outcome.

RESULTS

For all patients, the outcome was significantly better in SCD group compared to control group (P < 0.05). The results were similar in the subgroups of patients at stage 4 (P = 0.001) and stage 5 (P = 0.000), but not in the subgroup of patients at stage 3 (P = 0.121). For all patients, SCD was associated with a lower risk of CKD progression after adjusted for patients' characteristics (adjusted hazard ratio, 0.373; 95% confidence interval, 0.201-0.694; P 0.002).

CONCLUSION

SCD is an effective supplementary therapy to delay the progression of stages 4-5 CKD.

Comparative efficacy of adjuvant trastuzumab-containing chemotherapies for patients with early HER2-positive primary breast cancer: a network meta-analysis

BACKGROUND

Trastuzumab (H) with chemotherapy benefits patients with HER2+ breast cancer (BC); however, we lack head-to-head pairwise assessment of survival or cardiotoxicity for specific combinations. We sought to identify optimal combinations.

METHODS

We searched PubMed, updated October 2017, using keywords "Breast Neoplasms/drug therapy," "Trastuzumab," and "Clinical Trial" and searched Cochrane Library. Our search included randomized trials of adjuvant H plus chemotherapy for early-stage HER2+ BC, and excluding trials of neoadjuvant therapy or without data to obtain hazard ratios (HRs) for outcomes. Following PRISMA guidelines, one investigator did initial search; two others independently confirmed and extracted information; and consensus with another investigator resolved disagreements. Before gathering data, we set outcomes of overall survival (OS), event-free survival (EFS), and severe cardiac adverse events (SCAEs). Analyzing 6 trials and 13,621 patients, we made direct and indirect comparisons using network meta-analysis on HR for OS or EFS and on odds ratio (OR) for SCAE; ranked therapy was done based on outcomes using p scores.

RESULTS

Compared with anthracycline-cyclophosphamide with taxane (ACT), ACT with concurrent H (ACT+H) showed best OS (HR 0.63, 95% confidence interval [CI] 0.55, 0.72), followed by taxane and carboplatin (TC) with concurrent H (TC+H) (HR 0.77, 95% CI 0.59, 1) and ACT with sequential H (ACT-H) (HR 0.85, 95% CI 0.68, 1.05). Pairwise comparisons showed statistically significant OS benefit for ACT+H over others; similar results for EFS. TC+H showed statistically significant lower SCAE risk compared to ACT+H (OR 0.13, 95% CI 0.03, 0.61).

CONCLUSIONS

Concurrent H with ACT or TC showed most clinical benefit for early-stage HER2+ BC; TC+H had lowest cardiotoxicity.

In Vivo Effects of Stroma-Free Hemoglobin and Polyhemoglobin on Coagulation Factors in Rats

We studied the effects of rat stroma-free hemoglobin (rSFH), human stroma-free hemoglobin (hSFH), rat polyhemoglobin (rPoly), and human polyhemoglobin (hPoly) on coagulation factors in rats. Albumin and saline infused rats were controls. The infusion volume was 10% of the rat's blood volume. The concentrations of hemoglobin in this study were 7 g/dl.

Measurements for prothrombin time (PT) and activated partial thromboplastin time (PTT) were at 5 minutes, 2, 6, 24 and 72 hours after infusion. Factor X, fibrinogen, plasminogen, antithrombin III, and antiplasmin were followed at 24 and 72 hours after infusion. Compared with saline infused rats PT and PTT did not change significantly in those rats infused with Hb preparations. There was a transient increase of PTT from 2 to 24 hours after infusion in albumin infused rats. Factor X, fibrinogen, antithrombin III and antiplasmin showed no significant differences between Hb infused groups and saline infused group. Twenty-four hours and 72 hours after infusion plasminogen decreased in all groups except the albumin infused rats at 24 hours after infusion when compared with normal rat plasma pool. However, there were no significant differences in plasminogen levels between the hemoglobin infused groups and the control saline group.

Stroma-free and polyHb solutions (rSFH, hSFH, rPoly and hPoly) did not cause significant changes in prothrombin time and activated partial thromboplastin time in rats. The rats infused with hemoglobin solutions (rSFH, hSFH, rPoly, and hPloy) did not show significant differences in Factor X, fibrinogen, antithrombin III and antiplasmin levels compared with the control group.

On pseudolikelihood inference for semiparametric models with boundary problems

Consider a semiparametric model indexed by a Euclidean parameter of interest and an infinite-dimensional nuisance parameter. In many applications, pseudolikelihood provides a convenient way to infer the parameter of interest, where the nuisance parameter is replaced by a consistent estimator. The purpose of this paper is to establish the asymptotic behaviour of the pseudolikelihood ratio statistic under semiparametric models. In particular, we consider testing the hypothesis that the parameter of interest lies on the boundary of its parameter space. Under regularity conditions, we establish the equivalence between the asymptotic distributions of the pseudolikelihood ratio statistic and a likelihood ratio statistic for a normal mean problem with a misspecified covariance matrix. This result holds when the nuisance parameter is estimated at a rate slower than the usual rate in parametric models. We study three examples in which the asymptotic distributions are shown to be mixtures of chi-squared variables. We conduct simulation studies to examine the finite-sample performance of the pseudolikelihood ratio test.

3D dendritic-Fe2O3@C nanoparticles as an anode material for lithium ion batteries

3D dendritic Fe₂O₃ nanoparticles wrapped with carbon (denoted as 3DD-Fe₂O₃@C hereafter) were synthesized.

NFATc1 promotes prostate tumorigenesis and overcomes PTEN loss-induced senescence

Despite recent insights into prostate cancer (PCa)-associated genetic changes, full understanding of prostate tumorigenesis remains elusive due to complexity of interactions among various cell types and soluble factors present in prostate tissue. We found upregulation of Nuclear Factor of Activated T Cells c1 (NFATc1) in human PCa and cultured PCa cells, but not in normal prostates and non-tumorigenic prostate cells. To understand the role of NFATc1 in prostate tumorigenesis in situ, we temporally and spatially controlled the activation of NFATc1 in mouse prostate and showed that such activation resulted in prostatic adenocarcinoma with features similar to those seen in human PCa. Our results indicate that the activation of a single transcription factor, NFATc1 in prostatic luminal epithelium to PCa can affect expression of diverse factors in both cells harboring the genetic changes and in neighboring cells through microenvironmental alterations. In addition to the activation of oncogenes c-MYC and STAT3 in tumor cells, a number of cytokines and growth factors, such as IL1β, IL6, and SPP1 (Osteopontin, a key biomarker for PCa), were upregulated in NFATc1-induced PCa, establishing a tumorigenic microenvironment involving both NFATc1 positive and negative cells for prostate tumorigenesis. To further characterize interactions between genes involved in prostate tumorigenesis, we generated mice with both NFATc1 activation and Pten inactivation in prostate. We showed that NFATc1 activation led to acceleration of Pten-null–driven prostate tumorigenesis by overcoming the PTEN loss–induced cellular senescence through inhibition of p21 activation. This study provides direct in vivo evidence of an oncogenic role of NFATc1 in prostate tumorigenesis and reveals multiple functions of NFATc1 in activating oncogenes, in inducing proinflammatory cytokines, in oncogene addiction, and in overcoming cellular senescence, which suggests calcineurin-NFAT signaling as a potential target in preventing PCa.

Has racial difference in cause-specific death improved in older patients with late-stage breast cancer?

BACKGROUND

Research on temporal mortality trends for stage IV breast cancer is limited, especially among older patients by race. We evaluated factors associated with overall, breast cancer-specific and other-cause mortalities using contemporary population data.

PATIENTS AND METHODS

Using the Surveillance, Epidemiology, and End Results-Medicare linked data, we identified older women (≥ 66 years) with stage IV breast cancer diagnosed in 2002-2009. Overall mortality was estimated by the Kaplan-Meier method, compared by log-rank tests, and modeled by Cox models. Competing risk analysis was used to evaluate breast cancer-specific and other-cause mortalities.

RESULTS

The median overall survival time for non-Hispanic blacks improved from 8.6 months in 2002-2003 to 9.9 months in 2007-2009, whereas that for non-Hispanic whites improved from 12.1 to 14.8 months. In the multivariate model, the risk of breast cancer-specific death for patients diagnosed in 2007-2009 was significantly lower (P = 0.02), whereas the risk of other-cause mortality changed little (P = 0.88) compared with those risks for patients diagnosed in 2002-2003. Non-Hispanic blacks had the higher risk of both mortality types compared with non-Hispanic whites; a diagnosis time-race interaction term was not statistically significant for either cause of death.

CONCLUSION

Breast cancer-specific mortality among older women modestly improved from 2002 to 2009 across all races, but not other-cause mortality. Racial disparity in mortality persisted, but did not widen in this period. Efforts should be devoted to improving other-cause mortality for all women, with special attention toward decreasing breast cancer mortality for non-Hispanic black women.

The role of hydrogen sulfide in pathologies of the vital organs and its clinical application

Hydrogen sulfide (H(2)S) is one of the more recently recognised gaseous transmitters that have been shown to be involved in a large range of cellular functions. While H(2)S generally has pro-survival and anti-apoptotic effects, at higher concentrations, this effect is reversed and it becomes anti-proliferative and pro-apoptotic instead. H(2)S is also involved in a number of organ specific functions such as thermoregulation, modulating myocardial activity and broncho-dilation. H(2)S has organ protective effects in ischaemia, acting as a vasodilator and negative inotrope to reduce blood pressure. H(2)S generally has a protective effect in acute inflammation and oxidative stress from causes such as allergy and toxins. In chronic organ pathology, low H(2)S levels have been observed in a number of different diseases, while there is evidence that H(2)S may be beneficial in a number of chronic organ degenerations. A number of studies on human tissue and cell line conducted in the recent years shows H(2)S exerting largely similar effects in humans as those in animals. This may indicate that the pharmacological potential of H(2)S modulators could have therapeutic value in a large range of acute conditions such as ischaemia, toxin exposure as well as chronic conditions such as hypertension, lung diseases and neurodegenerative disease.

Impact of isoflurane on malignant capability of ovarian cancer in vitro

BACKGROUND

Metastatic recurrence of ovarian cancer is the foremost cause of postoperative mortality. With recent research indicating that inhalation of anaesthetics may influence cancer cell behaviour, this study investigated the effects of isoflurane on the expression of tumorigenic markers and proliferative capacity in ovarian cancer cells.

METHODS

Ovarian cancer (SK-OV3) cells were cultured and then exposed to 2% isoflurane for 2 h. The expression of markers involved in cell proliferation, angiogenesis, and migration were assessed up to 24 h after treatment using immunofluorescence staining, western blotting, and flow cytometry. The effects of isoflurane on in vitro angiogenesis and migration were also determined.

RESULTS

Isoflurane exposure significantly increased insulin-like growth factor (IGF)-1 and IGF-1R expression, cell cycle progression, and cell proliferation in SK-OV3 cells. Increased expression of the angiogenic markers vascular endothelial growth factor (VEGF) by 56% (P<0.05) and angiopoietin-1 by 62% (P<0.05) was also observed 24 h after isoflurane exposure together with an enhanced in vitro angiogenesis. Cell migration was significantly increased after exposure to isoflurane together with increased production of both matrix metalloproteinases 2 and 9 (both P<0.05) by almost five-fold relative to control. These effects were abolished when IGF-1R signalling was blocked either by neutralizing antibody or by small interfering RNA.

CONCLUSIONS

Our data indicate that isoflurane increases the malignant potential of ovarian cancer cells through the up-regulation of markers associated with the cell cycle, proliferation, and angiogenesis. This study warrants further investigations.

Simultaneous preconcentration of cadmium and chromium(III) in water samples by cloud point extraction and their determination by flame atomic absorption spectrometry

A sensitive and simple method for flame atomic absorption spectrometry determination of traces of cadmium and chromium(III) species in water samples after preconcentration by cloud point extraction has been developed. A novel complex agent of alizarin complexone with cadmium (Cd) and chromium (Cr(III)) was quantitatively extracted in surface primary alcohol ethoxylate-rich phase at 33 °C. The effects of experimental conditions including pH of sample solution, concentration of chelating agent and salt, equilibration temperature and time, and foreign ions were evaluated in order to enhance sensitivity of the method. Under optimal conditions, the low limit detections were 6.7 and 3.2 μg/L, and the enrichment factors were 24 and 20 for Cd and Cr(III), respectively. The relative standard deviations were 3.8 and 2.5% for Cd and Cr(II), respectively (n = 11). The high recoveries of the spiked Cd and Cr(III) ions were obtained in the range of 90-116%. The proposed method has been successfully applied for the determination of Cd and Cr(III) in water samples.

Cloud point extraction-flame atomic absorption spectrometry method for preconcentration and determination of trace cadmium in water samples

A method based on cloud point extraction (CPE) separation/preconcentration of trace cadmium (Cd) as a prior step to its determination by flame atomic absorption spectrometry has been developed. Cadmium reacted with 8-hydroxyquinoline to form hydrophobic chelates, which were extracted into the micelles of nonionic surfactant oligoethylene glycol monoalkyl ether (Genapol X-080) in an alkaline medium. Octanol was used to depress the cloud point of Genapol X-080 in the extraction process. The chemical variables that affect the CPE, such as pH of complexation reaction, amount of chelating agent, Genapol X-080 and octanol were evaluated and optimized. Under optimized conditions, linearity was obeyed in the range of 10-500 μg/L, with the correlation coefficient of 0.9993. For 5 mL of sample solution, the enhancement factor was about 20. The limit of detection and limit of quantification of the method were 0.21 and 0.63 μg/L, respectively. The relative standard deviations (n = 6) was 3.2% for a solution containing 100 μg/L of Cd. The accuracy of the preconcentration system was evaluated by recovery measurements on spiked water samples. Recoveries of spiked samples varied in the range of 94.1-103.8%.

Empirical likelihood-based confidence intervals for length-biased data

Logistic or other constraints often preclude the possibility of conducting incident cohort studies. A feasible alternative in such cases is to conduct a cross-sectional prevalent cohort study for which we recruit prevalent cases, that is, subjects who have already experienced the initiating event, say the onset of a disease. When the interest lies in estimating the lifespan between the initiating event and a terminating event, say death for instance, such subjects may be followed prospectively until the terminating event or loss to follow-up, whichever happens first. It is well known that prevalent cases have, on average, longer lifespans. As such, they do not constitute a representative random sample from the target population; they comprise a biased sample. If the initiating events are generated from a stationary Poisson process, the so-called stationarity assumption, this bias is called length bias. The current literature on length-biased sampling lacks a simple method for estimating the margin of errors of commonly used summary statistics. We fill this gap by using the empirical likelihood-based confidence intervals by adapting this method to right-censored length-biased survival data. Both large and small sample behaviors of these confidence intervals are studied. We illustrate our method by using a set of data on survival with dementia, collected as part of the Canadian Study of Health and Aging.

Assessment of genotoxic effects of flumorph by the comet assay in mice organs

The present study investigated the genotoxic effects of flumorph in various organs (brain, liver, spleen, kidney and sperm) of mice. The DNA damage, measured as comet tail length (µm), was determined using the alkaline comet assay. The comet assay is a sensitive assay for the detection of genotoxicity caused by flumorph using mice as a model. Statistically significant increases in comet assay for both dose-dependent and duration-dependent DNA damage were observed in all the organs assessed. The organs exhibited the maximum DNA damage in 96 h at 54 mg/kg body weight. Brain showed maximum DNA damage followed by spleen > kidney > liver > sperm. Our data demonstrated that flumorph had induced systemic genotoxicity in mammals as it caused DNA damage in all tested vital organs, especially in brain and spleen.

Overexpression of ubiquitin-specific protease 22 predicts poor survival in patients with early-stage non-small cell lung cancer

Ubiquitin-specific protease 22 (USP22), a novel ubiquitin hydrolase, has been implicated in oncogenesis and cancer progression in various types of human cancer. However, the clinical significance of USP22 expression in non-small cell lung cancer (NSCLC) has not been determined. In the present study, USP22 messenger RNA (mRNA) and protein levels were analyzed by quantitative real-time polymerase chain reaction (PCR) and western blot analysis in 30 cases of NSCLC and in corresponding non-tumor tissue samples. Furthermore, immunohistochemistry was performed to detect USP22 protein expression in 86 primary tumor tissues derived from clinically annotated NSCLC cases at stage I-II. In our analysis we found that both USP22 mRNA and protein levels in NSCLC tissues were significantly higher than those in corresponding non-tumor tissues and that there was a significant correlation between the expression of USP22 mRNA and protein (P=0.000, κ=0.732). In addition, a high-level of USP22 expression was observed in 53.3% (39 out of 86) cases and it was correlated with large tumor size (P=0.029) and lymph node metastasis (P=0.026). Patients with tumors displaying a high-level of USP22 expression showed significantly shorter survival (P=0.006, log-rank test). Importantly, multivariate analysis showed that high USP22 protein expression was an independent prognostic factor for NSCLC patients (P=0.003). In sum, our data suggest that USP22 plays an important role in NSCLC progression at the early stage, and that overexpression of USP22 in tumor tissues could be used as a potential prognostic marker for patients with early clinical stage of NSCLC.

Masticatory biomechanics and masseter fiber-type plasticity

Compared to force-resisting elements of the mammalian feeding apparatus, data on jaw-muscle plasticity are less common. This hinders our understanding of the role of force-producing structures in craniofacial development and integration. Thus, we investigated fiber-type abundance and cross-sectional area in the masseter muscle of growing rabbits subjected to diet-induced variation in masticatory stresses. Three loading cohorts were obtained as weanlings and raised until adult on different diets. Immediately following euthanasia, left-sided masseters were dissected away, weighed, and then divided into anterior, intermediate and posterior sections for fiber-type immunohistochemistry. These data were compared to mandibular proportions and biomineralization from the same subjects. Results indicate that growing mammals fed a tougher, fracture-resistant diet develop: absolutely and relatively lower numbers of Type I jaw-muscle fibers; absolutely larger fiber cross-sectional areas; and relative increases in the amount of Type II fibers. These analyses indicate that an early postweaning dietary shift can induce significant variation in muscle fiber types. Such norms of reaction are comparable to those observed in bony elements. Functionally, the processing of fracture-resistant foods results in jaw adductors potentially characterized by faster contraction times and higher force production capabilities, which may influence the frequency and amplitude of forces experienced by oral tissues.

[Relationship between hypotension during hemodialysis and autonomic dysfunction in diabetic hemodialysis patients]

OBJECTIVE

To observe the change of autonomic nerve function in diabetes mellitus(DM) patients who receive hemodialysis and to explore the relationship between this change and hypotension during hemodialysis.

METHODS

Twenty-five DM patients and 40 chronic glomerulonephritis(CGN) patients who received hemodialysis were checked. We tested their coefficient of variation R-R(CVR-R) in ECG, difference of systolic blood pressure between lying and standing positions, and serum parathyroid hormone(PTH); monitored the decrease of blood pressure during hemodialysis.

RESULTS

The rate(80.0%) of autonomic dysfunction(AD) in DM group is significantly higher than that(57.5%, P < 0.05) in CGN group. The rate(37.2%) of hypotension in those who had AD was significantly higher than that(18.2%, P < 0.05) in those who had normal autonomic nerve function during hemodialysis. No significant difference was found in PTH between each group.

CONCLUSION

DM patients who receive hemodialysis are often complicated with AD, which is one of the reasons that causes hypotension during hemodialysis.

The cytotoxicity of chromium in osteoblasts: effects on macromolecular synthesis

Exposure of an immortalized rat osteoblast cell line, FFC cells, to Cr VI resulted in inhibition of protein, DNA and RNA synthesis. Protein synthesis (3H-leucine incorporation) was most sensitive. There was no inhibition of the incorporation of 3H-proline into collagen at the concentrations which inhibited general protein synthesis (1 microM), but synthesis of extracellular collagen fibers was markedly decreased by concentrations of 0.5 microM Cr VI and above. This indicates that some aspect of the post-translational processing of the collagen fibers is sensitive to Cr VI inhibition. Collagen fiber formation was not inhibited by Cr III (which does not penetrate the cell membrane) or when Cr VI was reduced to Cr III extracellularly. This suggests that the Cr VI inhibits an intracellular stage of post-translational collagen processing. Both Cr VI and Cr III inhibit collagenase activity, the former being more potent but less efficacious. Our results suggest that leakage of chromium ions from orthopedic implants may cause a decrease in the proliferation and infiltration of osteoblasts around the implant, and a reduction in the synthesis and altered turnover of collagen in extracellular matrix. These effects will influence the osseointegration of implants, the osteolytic response, and ultimately the stable life-time of the implants.

Arbuscular mycorrhizal fungi alter phosphorus relations of broomsedge (Andropogon virginicus L.) plants

Broomsedge (Andropogon virginicus L.) is a dominant grass revegetating many abandoned coal-mined lands in West Virginia, USA. Residual soils on such sites are often characterized by low pH, low nutrients, and high aluminium. Experiments were conducted to assess the resistance of broomsedge to limited phosphorus (Pi) availability and to investigate the role that arbuscular mycorrhizal (AM) fungi play in aiding plant growth under low Pi conditions. Pregerminated mycorrhizal and non-mycorrhizal seedlings were grown in a sand-culture system with nutrient solutions containing Pi concentrations ranging from 10 to 100 microM for 8 weeks. Non-mycorrhizal plants exhibited severe inhibition of growth under Pi limitation (<60 microM). Colonization by AM fungi (combined Glomus clarum Nicolson & Schenck and Gigaspora gigantea (Nicol. & Gerd.) Gerd. & Trappe) greatly enhanced host plant growth at low Pi concentrations, but did not benefit growth when Pi was readily available (100 microM). In comparison to non-mycorrhizal plants, mycorrhizal plants had higher phosphorus use efficiency at low Pi concentrations and maintained nearly constant tissue nutrient concentrations across the gradient of Pi concentrations investigated. Manganese (Mn) and sodium (Na) accumulated in shoots of non-mycorrhizal plants under Pi limitation. Mycorrhizal plants exhibited lower instantaneous Pi uptake rates and significantly lower C(min) values compared to non-mycorrhizal plants. These patterns suggest that the symbiotic association between broomsedge roots and AM fungi effectively maintains nutrient homeostasis through changes in physiological properties, including nutrient uptake, allocation and use. The mycorrhizal association is thus a major adaptation that allows broomsedge to become established on infertile mined lands.

[The predomination of rotavirus G3 serotype among children with diarrhea in Lulong County in 1998]

OBJECTIVE

To investigate the epidemiology of rotavirus diarrhea among children in rural population.

METHODS

120 stool specimens collected from children with diarrhea during the winter of 1998 in Lulong County, Hebei Province were examined for rotavirus by PAGE and ELISA and for serotype by ELISA and PCR.

RESULTS

Rotavirus was detected in children aged between 2-24 months. The positive rate of rotavirus was 39.2% and the ratio of male to female was 1-1.47. All rotavirus RNA profiles were long pattern. The distribution of rotavirus serotypes was type 3(61.7%), followed by type 1(36.2%), and type 4(6.4%).

CONCLUSIONS

The epidemiology of rotavirus diarrhea during 1998 rotavirus season in Lulong County was similar to that of other regions in China, but rotavirus serotype G3 was a prevalent strain in Lulong County, which was uncommon and different from the predominant G1 in other places throughout China.

[Study of continuous wavelet transform on detecting and enhancing blood vessel in DSA image]

Low contrast is the shortcoming of the image in Digital Subtraction Angiography. This paper presents a new approach for the enhancement of blood volume in DSA image. The wavelet transform was applied to detect blood edges, and then the image contrast was enhanced by the method of contrast stretched. Because the continuous wavelet adopted in this study can detect gray variety in different orientations, the blood vessel edge detected by this algorithm is more precise and complete. Moreover, because the module of image noise by wavelet transform is smaller, the algorithm can protrude blood vessel but restrain noise in background. The processing result showed a very good optical effect of 3 dimensional objects for medical diagnoses.

Facile synthesis of a comb-like mannohexaose: a trimer of the disaccharide repeating unit of the cell-wall mannans of Aphanoascus mephitatus and related species

An efficient method for the preparation of a comb-like mannohexaose having alpha-(1-->6) and alpha-(1-->2) linkages has been described using 6-O-acetyl-2-O-benzoyl-3,4-di-O-benzyl-alpha-D-mannopyranosyl trichloroacetimidate as the key glycosyl donor in an 'inverse Schmidt' procedure.