不同性别C57BL/6小鼠肠道胆汁酸组成的差异性研究

随着人们对宿主肠道菌群的日益关注,关于胆汁酸与肠道菌群之间复杂关系的研究也越来越多.因肠道组织结构的复杂性和肠道菌群分布差异性,不同肠段胆汁酸的分布、表达及其生物学功能仍有待进一步研究.本文采用基于超高效液相色谱-三重四极杆-质谱联用（UPLC-QqQ-MS）的靶向代谢组分析结合基于核磁共振（NMR）波谱的非靶向代谢组分析方法,通过比较不同性别C57BL/6小鼠肠道各区段胆汁酸及粪样代谢组的变化水平,发现雌、雄小鼠不同肠段中胆汁酸的分布各不相同.另外,肠道下段各胆汁酸的性别差异性更为明显,以盲肠的性别差异性最为显著,这可能与盲肠的菌群微生态更为丰富有关.该研究为不同性别模型小鼠胆汁酸的代谢表型及其与肠道菌群的相互作用提供了基础研究数据.     

Effects of a novel ultrasound contrast agent with long persistence on right ventricular pressure: Comparison with SonoVue

This work investigated the effect of infusion of a self-made ultrasound contrast agent with long persistence (named ZHIFUXIAN) on rat right ventricular pressure and made a preliminary evaluation on the relative safety of the novel microbubbles. Normal saline, SonoVue and ZHIFUXIAN were injected through caudal vein at the total volume of 0.5 ml for each injection. The right ventricular systolic pressure (RVSP) and end-diastolic pressure (RVEDP) were monitored and the changes of the pressure were compared with baseline readings. RVSP increased when saline, SonoVue or ZHIFUXIAN were injected, the greatest change being after SonoVue (about 2 mm Hg), but there was no statistical significance compared with baseline (P > 0.05). There was no significant difference in RVSP between saline, SonoVue and ZHIFUXIAN at any time point. Also, there was no significant difference in RVEDP between groups at each time point and between different time points in each group. The results indicate that the self-made microbubbles effect on right ventricular hemodynamics is equivalent to that of normal saline at the same volume needed for effective enhanced imaging, demonstrating that it does not produce changes in right ventricular blood pressure under the study conditions. Pathological examination also showed it had no obvious influence on lung, liver and kidney.     

Gd-DTPA-induced dynamic metabonomic changes in rat biofluids

ObjectivesThe purposes of this study were (1) to detect the dynamic metabonomic changes induced by gadopentetate dimeglumine (Gd-DTPA) and (2) to investigate the potential metabolic disturbances associated with the pathogenesis of nephrogenic systemic fibrosis (NSF) at the early stage.MethodsA nuclear magnetic resonance (NMR)-based metabolomics approach was used to investigate the urinary and serum metabolic changes induced by a single tail vein injection of Gd-DTPA (dosed at 2 and 5 mmol/kg body weight) in rats. Urine and serum samples were collected on days 1, 2 and 7 after dosing.ResultsMetabolic responses of rats to Gd-DTPA administration were systematic involving changes in lipid metabolism, glucose metabolism, TCA cycle, amino acid metabolism and gut microbiota functions. Urinary and serum metabonomic recovery could be observed in both the 2 and 5 mmol/kg body weight group, but the metabolic effects of high-dosed (5 mmol/kg body weight) Gd-DTPA lasted longer. It is worth noting that hyperlipidemia was observed after Gd-DTPA injection, and nicotinate might play a role in the subsequent self-recovery of lipid metabolism. The disturbance of tyrosine, glutamate and gut microbiota metabolism might associate with the progression of NSF.ConclusionThese findings offered essential information about the metabolic changes induced by Gd-DTPA, and could be potentially important for investigating the pathogenesis of NSF at the early stage. Moreover, the recovery of rats administrated with Gd-DTPA may have implications in the treatment of early stage NSF.     

仿生技术在转基因大豆中镍形态分析和生物可给性评价中的应用

转基因的食品安全问题一直是科学家和公众关注的焦点,其微量元素的生物可给性研究可为转基因食品的安全评价提供参考。以“胃肠仿生消化、肠道微生物代谢、脂质体仿生物膜亲合吸附”构建胃肠功能模型,用于大豆(转基因大豆和普通大豆)的样品前处理,以脂质体亲合态、水溶态界定消化食糜中镍化合物的形态, 以人体可吸收部分的脂质体亲合态评价大豆中镍的生物可给性。经胃肠消化和微生物代谢,大豆食糜中镍配合物以水溶态为主;胃肠消化、肠道微生物代谢均对镍配合物的生物可给性起促进作用;转基因大豆和普通大豆中镍的生物可给性分别为4.1%和3.3%,即大豆转基因后镍生物可给性提高24%;但转基因大豆中脂质体结合态镍含量122.3 ng·g-1,仅为普通大豆的36%。     

净化沥青的傅里叶变换红外光谱分峰拟合定量分析

高温煤焦油沥青是人造炭材料的优质原料。为了获得高品质人造炭材料,必须对原料沥青进行净化处理,使得净化沥青具有合理的分子量分布、较高芳香缩合度和适宜的脂肪族侧链结构,炭化后才能生成易于石墨化的趋于规整的碳微晶结构。分别以中温沥青和热聚合改性沥青为原料,采用两种净化分离处理方法,得到四种净化沥青(RP-1,RP-2,RP-3和RP-4)。以四种净化沥青的傅里叶变换红外光谱数据为基础,结合分峰拟合数学方法,准确获得了净化沥青的芳香性指数(Iar)、支链化指数(CH₃/CH₂)、OH官能团的存在形式及分布情况和其他基础官能团含量。由分析研究结果可知,四种净化沥青均具有较大的芳香缩合度。RP-3芳香性指数高达0.90,芳香缩合度最高。RP-4支链化指数仅为0.07,脂肪族侧链数量较多、碳链较长。四种净化沥青中OH官能团存在形式有明显不同。研究结果将为人造炭/石墨材料的原料优选提供理论支持。     

Ultrasonic assisted extraction,characterization and gut microbiota-dependent anti-obesity effect of polysaccharide from Pericarpium Citri Reticulatae 'Chachiensis'

Pericarpium Citri Reticulatae 'Chachiensis' (PCRC), the premium aged pericarps of Pericarpium Citri Reticulatae, is widely used in traditional Chinese medicines with a diversity of promising bioactivity. Herein we report the extraction, characterization and underlying mechanism of anti-metabolic syndrome of an arabinan-rich polysaccharide from PCRC (PCRCP). This polysaccharide was obtained in a 7.0% yield by using ultrasound-assisted extraction under the optimized conditions of 30 mL/g liquid-to-solid ratio, 250 W ultrasound power for 20 min at 90 °C with pH 4.5. The PCRCP with an average molecular weight of 122.0 kDa, is mainly composed of D-galacturonic acid, arabinose and galactose, which may link via 1,4-linked Gal(p)-UA, 1,4-linked Ara(f) and 1,4-linked Gal(p). Supplementation with PCRCP not only effectively alleviated the weight gain, adiposity and hyperglycemia, but also regulated the key metabolic pathways involved in the de novo synthesis and β-oxidation of fatty acid in high-fat diet (HFD)-fed mice. Furthermore, PCRCP treatment caused a significant normalization in the intestinal barrier and composition of gut microbiota in mice fed by HFD. Notably, PCRCP selectively enriched Lactobacillus johnsonii at the family-genus-species levels, a known commensal bacterium, the level of which was decreased in mice fed by HFD. The depletion of microbiome induced by antibiotics, significantly compromised the effects of anti-metabolic syndrome of PCRCP in mice fed by HFD, demonstrating that the protective phenotype of PCRCP against anti-obesity is dependent on gut microbiota. PCRCP is exploitable as a potential prebiotic for the intervention of obesity and its complications.     

Effect of thermobaric treatment on crystallinity of carbon materials

Abstract

The process of ordering of different carbon materials in the presence of solvent metal Mn₆₀-Ni₄₀ under the pressure of 3.9 GPa and temperature of 1250–1370° C was studied. The rearrangment of imperfect materials structure into the graphite one occurred through an intermediate layer modification together with diamond formation, the intensity of the latter being significantly higher on carbon materials having the most imperfect structure.     

中老年糖尿病轻重度患者血清中的铁铬钴镍

对１２８例中老年糖尿病患者进行了血清中微量元素铁,铬,钴,镍的含量测定,并与正常对照进行了比较。结果表明,血糖正常组和高血糖组的糖尿病患者血清铁铬水平均低于正常对照组,且两病例组与对照组比较铬水平有非常显著差异（Ｐ〈０．０１）。血清镍水平患病初期降低,后升至正常,高血糖组与对照组比较差异显著（Ｐ〈０．０５）,两病例组间差异非常显著（Ｐ〈０．００１）,血清钴水平随情加重而逐渐升高,但无统计学上的显著     

表面增强拉曼散射检测分析物分子的研究进展

表面增强拉曼散射(SERS)技术具有高效,灵敏,无损检测等特点,能实现对分析物分子的极低浓度检测,被广泛应用于痕量分析领域.在生产和生活中,有些毒性物质或非法添加剂被人体摄入或长期接触后,在体内不断累积,最终导致中毒或者组织器官发生病变;环境中过量的有害物质残留,由于其本身的毒性或者使菌株和害虫产生抗药性而造成的生态系...     

Changes in chemical and microbiological characteristics of goat cheese made from raw,pasteurized or high-pressure-treated milk

Abstract

High-pressure treatment offers to the dairy industry a new technique for food preservation. Very little research is available on the use of high pressure and its potential for cheesemaking. The use of high-pressure treated milk to produce goat cheese has been studied. The effect of high pressure on the ripening process of goat cheese, including the microbiological quality of goat milk and cheese has been included.     

Cognitive, cardiac, and physiological safety studies in ultra high field magnetic resonance imaging

A systematic analysis of the effect of an 8.0 tesla static magnetic field on physiological and/or cognitive function is presented in the normal volunteer and in the swine. A study of ten human subjects revealed no evidence of detectable changes in body temperature, heart rate, respiratory rate, systolic pressure, and diastolic blood pressure after 1 hour of exposure. In addition, no cognitive changes were detected. Important ECG changes were noted which were related both to the position of the subject in the magnet and to the absolute strength of the magnetic field. As such, the ECG tracing at 8 tesla was not diagnostically useful. Nonetheless, all subjects exhibited normal ECG readings both before and following exposure to the 8 tesla field. Cardiac function was also examined in detail in the swine. No significant changes in body temperature, heart rate, left ventricular pressure, left ventricular end diastollic pressure, time rate of change of left ventricular pressure, myocardial stiffness index, cardiac output, systolic volume, troponin, and potassium levels could be detected following 3 h of exposure to a field strength of 8.0 tesla. It is concluded that no short term cardiac or cognitive effects are observed following significant exposure to a magnetic field of up to 8.0 tesla.     

The13C/12C and 2H/1H Ratios of Trichloroethene,Tetrachloroethene and Their Metabolites

Abstract

Isotope ratios of technically and biologically produced halogenated hydrocarbons (HHC) are presented. Compared to the parent compounds, there is a significant enrichment of deuterium depending on the manner of production, whereas the carbon isotope ratio was only slightly influenced. Furthermore, there is nearly no alteration of the carbon isotope ratio due to biological degradation, so that the carbon fingerprint of the parent compounds is maintained in the metabolites. In contrast to this, the hydrogen isotope ratio of the metabolites reflects the ratio of the surrounding water. These results show that the isotopic fingerprint is a useful tool to distinguish between age, different charges of chemical dumping, and in addition to that, whether there is a contamination with technical products or residual metabolites.     

Phytoremediation of Arsenic: Fundamental Studies,Practical Applications,and Future Prospects

Abstract

Arsenic is a toxic element that is naturally present but is also introduced through a variety of anthropogenic activities. Phytoremediation, which is the use of green plants to minimize the impact of toxic substances, has been widely used for arsenic. Phytoextraction employs plants to accumulate toxins into aboveground biomass. Pteris vittata, commonly known as the brake fern, was the first species used for phytoextraction and the most widely investigated, although other Pteris plants have been successfully employed. Several studies have investigated the accumulation of arsenic in food plants to assess possible impact upon human health. Phytostabilization, which involves the use of contaminant-immobilizing soil amendments with plants to reduce contaminant availability, has been successfully employed for arsenic. It is expected that phytoremediation will be employed in the future as a low-cost alternative for the remediation of arsenic in soil.     

Critical damage to the cellular organelles of Saccharomyces cerevisiae under sublethal conditions upon high pressure carbon dioxide treatment

ABSTRACT

High pressure carbon dioxide treatment is a non-thermal pasteurization technique. However, critical damage, resulting from the treatment, to microbial cells has not been observed directly, and the detailed mechanism of the microbicidal activity is not understood. In this study, we analyzed the damage to Saccharomyces cerevisiae organelles, which were visualized using organelle-specific GFP fusion proteins. Yeast strains were subjected to high pressure carbon dioxide treatments at 30°C and 4.0?MPa for 2–8?h. Reduction in yeast cell viability was accompanied by the disruption of endoplasmic reticulum, nuclear membrane, Golgi body, and nucleolus. However, visible damage to the cell membrane was not observed. Fluorescence microscopy was utilized to confirm that high pressure carbon dioxide treatment damaged membranes of major organelles, but not the cell membrane.     

Effect of pressure and blanching treatments on endogenous enzymatic activity and vitamin C content of bell pepper fruit

The effect of high pressure and blanching treatments on green bell pepper was studied. Both processes caused changes on pectin methylesterase activity and vitamin C and protein contents. Polygalacturonase activity was not detected in any of the samples studied. There seems to be no significant difference caused by both types of processing.     

Glottal airflow and transglottal air pressure measurements for male and female speakers in soft, normal, and loud voice

Measurements on the inverse filtered airflow waveform (the "glottal waveform") and of estimated average transglottal pressure and glottal airflow were made from noninvasive recordings of productions of syllable sequences in soft, normal, and loud voice for 25 male and 20 female speakers. Statistical analyses showed that with change from normal to loud voice, both males and females produced loud voice with increased pressure, accompanied by increased ac flow and increased maximum airflow declination rate. With change from normal voice, soft voice was produced with decreased pressure, ac flow and maximum airflow declination rate, and increased dc and average flow. Within the loudness conditions, there was no significant male-female difference in air pressure. Several glottal waveform parameters separated males and females in normal and loud voice. The data indicate higher ac flow and higher maximum airflow declination rate for males. In soft voice, the male and female glottal waveforms were more alike, and there was no significant difference in maximum airflow declination rate. The dc flow did not differ significantly between males and females. Possible relevance to biomechanical differences and differences in voice source characteristics between males and females and across loudness conditions is discussed.     

A Preliminary Study of Vocal Health Among Collegiate A Cappella Singers

ObjectiveCollegiate a cappella groups have grown significantly in popularity and prominence; however, there have been few studies that evaluate the vocal health of this subgroup of young singers. The objective of this preliminary study was to conduct a multiparametric evaluation of the vocal health characteristics of a sample of collegiate a cappella singers. We further tested whether differences in vocal health assessments exist between a cappella singers with and without vocal training and trained collegiate singers who do not participate in a cappella groups.Study designPoint prevalence study.MethodsForty-one collegiate singers participated in this study. Participants were divided into the following three groups: trained singers (TS), trained a cappella singers (ATS), and untrained a cappella singers (AUS). Participants were administered a set of surveys to assess self-perception of singing voice health and perceived access and attitudes toward voice-related health care. Acoustic and laryngoscopic assessments of participant's speaking and singing voice was performed and validated vocal health questionnaires administered as a means to objectively evaluate for the presence of voice problems.ResultsOverall, 87.5% of the ATS and 60% of the AUS groups reported experiencing problems with their singing voice. However, no vocal abnormalities were detected during laryngoscopic and acoustic assessments. Furthermore, minimal differences between any of the measured vocal health parameters were observed between the TS, ATS, and AUS groups.ConclusionCollectively, a high percentage of collegiate a cappella singers with and without vocal training report singing voice problems. However, our sample of a cappella singers did not have increased singing voice problems as compared to vocally trained collegiate singers not in a cappella groups. We did find that a cappella singers may be more inclined to seek information about maintaining a healthy singing voice from their fellow musicians as opposed to singing teachers or other voice health professionals. Singing teachers, otolaryngologists, and speech-language pathologists may need to play a more active role in educating a cappella singers regarding maintaining good vocal health.     

Pressure-driven molecular dynamics simulations of water transport through a hydrophilic nanochannel

ABSTRACT

Transport of fluids inside porous materials is relevant to many fields of application. Non-equilibrium molecular dynamics simulation is a powerful technique to explore fluid transport through porous media at the molecular scale. In this work, we compared two commonly used methods for studying pressure-driven transport. The first method was based on the application of an external force field on each fluid particle. The second method made use of two movable walls, acting as pistons, so as to generate transport. These two methods were used to study water transport inside a cylindrical hydrophilic silica nanopore. Several pressure differences were considered from 20 bar to 1000 bar. The results were compared to the theoretical Poiseuille fluid flow. No significant difference was found between the two methods. However, a substantial water flow enhancement was observed compared with the theoretical flow. Both the structural and dynamical properties of water remained unaffected by the applied pressure difference.     

Capture of pure toxic gases through porous materials from molecular simulations

ABSTRACT

In the last three decades, the air pollution is the main problem to affect human health and the environment in China and its contaminants include SO_2, NH_3, H₂S, NO₂, NO and CO. In this work, we employed grand canonical Monte Carlo simulations to investigate the adsorption capability of metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) for these toxic gases. Eighty-nine MOFs and COFs were studied, and top-10 adsorption materials were screened for each toxic gas at room temperature. Dependence of the adsorption performance on the geometry and constructed element of MOFs/COFs was determined and the adsorption conditions were optimised. The open metal sites have mainly influenced the adsorption of NH₃, H₂S, NO₂ and NO. Especially, the X-DOBDC and XMOF-74 (X = Mg, Co, Ni, Zn) series of materials containing open metal sites are all best performance for adsorption of NH₃ to illustrate the importance of electrostatic interaction. Our simulation results also showed that ZnBDC and IRMOF-13 are good candidates to capture the toxic gases NH_3, H₂S, NO₂, NO and CO. This work provides important insights in screening MOF and COF materials with satisfactory performance for toxic gas removal.     

在氢气氛围下利用电弧放电法大量制备纳米碳管的研究

利用以石墨为电极的直流电弧放电法,在氢气氛围下制备出了纳米碳管.实验结果表明,在阴极上形成的碳素堆积物中,其前端表面及其内部都生成了纳米碳管.经扫描电子显微镜和透射电子显微镜观察分析发现,所生成的纳米碳管其形态构造在氢气的压强和直流电弧电流发生变化时,没有显著差异.在氢气压强为11999Pa,直流电弧电流为60A时,得到了大量的、管径较均匀、直而长的纳米碳管. 关键词：