104 research outputs found

    Facile Ozonation of Light Alkanes to Oxygenates with High Atom Economy in Tunable Condensed Phase at Ambient Temperature

    Get PDF
    We have demonstrated the oxidation of mixed alkanes (propane, n-butane, and isobutane) by ozone in a condensed phase at ambient temperature and mild pressures (up to 1.3 MPa). Oxygenated products such as alcohols and ketones are formed with a combined molar selectivity of >90%. The ozone and dioxygen partial pressures are controlled such that the gas phase is always outside the flammability envelope. Because the alkane–ozone reaction predominantly occurs in the condensed phase, we are able to harness the unique tunability of ozone concentrations in hydrocarbon-rich liquid phases for facile activation of the light alkanes while also avoiding over-oxidation of the products. Further, adding isobutane and water to the mixed alkane feed significantly enhances ozone utilization and the oxygenate yields. The ability to tune the composition of the condensed media by incorporating liquid additives to direct selectivity is a key to achieving high carbon atom economy, which cannot be achieved in gas-phase ozonations. Even in the liquid phase, without added isobutane and water, combustion products dominate during neat propane ozonation, with CO2 selectivity being >60%. In contrast, ozonation of a propane+isobutane+water mixture suppresses CO2 formation to 15% and nearly doubles the yield of isopropanol. A kinetic model based on the formation of a hydrotrioxide intermediate can adequately explain the yields of the observed isobutane ozonation products. Estimated rate constants for the formation of oxygenates suggest that the demonstrated concept has promise for facile and atom-economic conversion of natural gas liquids to valuable oxygenates and broader applications associated with C–H functionalization

    Do the Disc Degeneration and Osteophyte Contribute to the Curve Rigidity of Degenerative Scoliosis?

    Get PDF
    The factors associated with lateral curve flexibility in degenerative scoliosis have not been well documented. Disc degeneration could result in significant change in stiffness and range of motion in lateral bending films. The osteophytes could be commonly observed in degenerative spine but the relationship between osteophyte formation and curve flexibility remains controversial. The aim of the current study is to clarify if the disc degeneration and osteophyte formation were both associated with curve flexibility of degenerative scoliosis

    Scoliosis Related Information on the Internet in China: Can Patients Benefit from This Information?

    Get PDF
    Background: There has been an increasing popularity of searching health related information online in recent years. Despite that considerable amount of scoliosis patients have shown interest in obtaining scoliosis information through Internet, previous studies have demonstrated poor quality of online information. However, this conclusion may vary depending on region and culture. Since China has a restricted Internet access outside of its borders, the aim of this study is to evaluate the quality of scoliosis information available online using recognized scoring systems and to analyze the Internet as a source of health information in China. Methods: A survey-based questionnaire was distributed to 280 respondents at outpatient clinics. Information on demographics and Internet use was collected. Binary logistic analysis was performed to identify possible predictors for the use of Internet. In addition, the top 60 scoliosis related websites assessed through 4 search engines were reviewed by a surgeon and the quality of online information was evaluated using DISCERN score and JAMA benchmark. Results: Use of the Internet as a source for scoliosis related information was confirmed in 87.8% of the respondents. College education, Internet access at home and urban residence were identified as potential predictors for Internet use. However, the quality of online scoliosis related information was poor with an average DISCERN score of 27.9±11.7 and may be misleading for scoliosis patients. Conclusion: The study outlines the profile of scoliosis patients who use the Internet as a source of health information. It was shown that 87.8% of the scoliosis patients in outpatient clinics have searched for scoliosis related information on Internet. Urban patients, higher education and Internet access at home were identified as potential predictors for Internet search. However, the overall quality of online scoliosis related information was poor and confusing. Physician based websites seemed to contain more reliable information

    Primerjalna študija genetske raznovrstnosti talnih bakterij in gliv v različnih sukcesijah vegetacije na krasu v provinci Guizhou, Kitajska

    Get PDF
    To study the soil genetic diversity of bacteria and fungi in different vegetation successions (grassland, shrubbery, primary forest and secondary forest) from the karst area, the Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) technology was applied. The results showed that: (1) the diversity of bacterial communities and the fungal communities in karst area were higher than non karst area in each vegetation succession. Compared with the survey from bacterial (the Shannon index was 2.97 in primary forest, 2.91 in secondary forest, 3.18 in shrubbery, 3.14 in grassland and 2.68 in non karst), fungal diversity between karst areas (the Shannon index was 3.56 in primary forest, 3.78 in secondary forest, 3.73 in shrubbery and 3.70 in grassland) and non karst areas (the Shannon index was 3.08) was more evident, which may be related to the alterations of the composition of plant community and the source of carbon in soil with the vegetation succession of karst ecosystem; (2) The comparation of bacterial diversity index and the richness comprehensively evaluated as follows: shrubbery > grassland > primary forest > nsecondary forest. The diversity index and the richness of fungal communities was as follows: secondary forest > shrubbery > grassland > primary forest. The results suggest that the fungal communities have been greatly changed via vegetation successions, but the diversity index and the richness of the bacterial communities have not been seriously affected. The results provide scientific basis for understanding karst surface ecosystem, which contributes to the future aim of protecting the karst from desertification.Za proučevanje genetske pestrosti talnih bakterij in gliv v različnih sukcesijah vegetacije (travišče, grmičevje, primarni gozd in sekundarni gozd) na krasu je bila uporabljena tehnologija verižne reakcije s polimerazo-denaturirajoča gradientna gelska elektroforeza (PCR-DGGE). Rezultati raziskave so pokazali, da: (1) je bila v vsaki sukcesiji vegetacije pestrost bakterijskih in glivnih združb na kraškem območju višja kot na nekraškem. V primerjavi z bakterijsko raznovrstnostjo (Shannonov indeks je bil 2,97 v primarnem gozdu, 2,91 v sekundarnem gozdu, 3,18 v tleh grmičevja, 3,14 v tleh travišč in 2,68 v nekraškem območju) je bila raznovrstnost gliv med kraškimi območji (Shannonov indeks je bil v primarnem gozdu 3,56, 3,78 v sekundarnem gozdu, 3,73 v tleh grmičevja in 3,70 v tleh travišč) in nekraškimi (Shannonov indeks je bil 3,08) jasneje izražena. To je lahko povezano s spremembami v sestavi rastlinske združbe in vira ogljika v tleh glede na stanje sukcesije v vegetaciji kraškega ekosistema. (2) Primerjava kazalnikov bakterijske raznovrstnosti in abundance je bila celostno ovrednotena in sledi takole: grmičevje > travišče > primarni gozd > sekundarni gozd. Kazalnika raznovrstnosti in abundance glivnih združb kažeta sledeči trend: sekundarni gozd > grmičevje > travišče > primarni gozd. Rezultati izkazujejo, da so se glivne združbe precej spremenile zaradi sukcesije v vegetaciji, vendar pa na drugi strani ni bilo bistvenega vpliva na kazalnika bakterijske raznovrstnosti in abundance. Rezultati med drugim dajejo tudi znanstveno podlago za razumevanje delovanja kraškega površinskega ekosistema, kar ključno prispeva k cilju zaščite krasa pred dezertifikacijo (širjenjem puščav)

    Adherence to a Mediterranean diet is associated with a lower risk of diabetic kidney disease among individuals with hyperglycemia:a prospective cohort study

    Get PDF
    BACKGROUND: Type 2 diabetes is associated with a variety of complications, including micro- and macrovascular complications, neurological manifestations and poor wound healing. Adhering to a Mediterranean Diet (MED) is generally considered an effective intervention in individuals at risk for type 2 diabetes mellitus (T2DM). However, little is known about its effect with respect to the different specific manifestations of T2DM. This prompted us to explore the effect of MED on the three most significant microvascular complications of T2DM: diabetic retinopathy (DR), diabetic kidney disease (DKD), and vascular diabetic neuropathies (DN). METHODS: We examined the association between the MED and the incidence of these microvascular complications in a prospective cohort of 33,441 participants with hyperglycemia free of microvascular complications at baseline, identified in the UK Biobank. For each individual, we calculated the Alternate Mediterranean Diet (AMED) score, which yields a semi-continuous measure of the extent to which an individual's diet can be considered as MED. We used Cox proportional hazard models to analyze hazard ratios (HRs) and 95% confidence intervals (CIs), adjusting for demographics, lifestyle factors, medical histories and cardiovascular risk factors. RESULTS: Over a median of 12.3 years of follow-up, 3,392 cases of microvascular complications occurred, including 1,084 cases of diabetic retinopathy (DR), 2,184 cases of diabetic kidney disease (DKD), and 632 cases of diabetic neuropathies (DN), with some patients having 2 or 3 microvascular complications simultaneously. After adjusting for confounders, we observed that higher AMED scores offer protection against DKD among participants with hyperglycemia (comparing the highest AMED scores to the lowest yielded an HR of 0.79 [95% CIs: 0.67, 0.94]). Additionally, the protective effect of AMED against DKD was more evident in the hyperglycemic participants with T2DM (HR, 0.64; 95% CI: 0.50, 0.83). No such effect, however, was seen for DR or DN. CONCLUSIONS: In this prospective cohort study, we have demonstrated that higher adherence to a MED is associated with a reduced risk of DKD among individuals with hyperglycemia. Our study emphasizes the necessity for continued research focusing on the benefits of the MED. Such efforts including the ongoing clinical trial will offer further insights into the role of MED in the clinical management of DKD.</p

    Adherence to a Mediterranean diet is associated with a lower risk of diabetic kidney disease among individuals with hyperglycemia:a prospective cohort study

    Get PDF
    BACKGROUND: Type 2 diabetes is associated with a variety of complications, including micro- and macrovascular complications, neurological manifestations and poor wound healing. Adhering to a Mediterranean Diet (MED) is generally considered an effective intervention in individuals at risk for type 2 diabetes mellitus (T2DM). However, little is known about its effect with respect to the different specific manifestations of T2DM. This prompted us to explore the effect of MED on the three most significant microvascular complications of T2DM: diabetic retinopathy (DR), diabetic kidney disease (DKD), and vascular diabetic neuropathies (DN). METHODS: We examined the association between the MED and the incidence of these microvascular complications in a prospective cohort of 33,441 participants with hyperglycemia free of microvascular complications at baseline, identified in the UK Biobank. For each individual, we calculated the Alternate Mediterranean Diet (AMED) score, which yields a semi-continuous measure of the extent to which an individual's diet can be considered as MED. We used Cox proportional hazard models to analyze hazard ratios (HRs) and 95% confidence intervals (CIs), adjusting for demographics, lifestyle factors, medical histories and cardiovascular risk factors. RESULTS: Over a median of 12.3 years of follow-up, 3,392 cases of microvascular complications occurred, including 1,084 cases of diabetic retinopathy (DR), 2,184 cases of diabetic kidney disease (DKD), and 632 cases of diabetic neuropathies (DN), with some patients having 2 or 3 microvascular complications simultaneously. After adjusting for confounders, we observed that higher AMED scores offer protection against DKD among participants with hyperglycemia (comparing the highest AMED scores to the lowest yielded an HR of 0.79 [95% CIs: 0.67, 0.94]). Additionally, the protective effect of AMED against DKD was more evident in the hyperglycemic participants with T2DM (HR, 0.64; 95% CI: 0.50, 0.83). No such effect, however, was seen for DR or DN. CONCLUSIONS: In this prospective cohort study, we have demonstrated that higher adherence to a MED is associated with a reduced risk of DKD among individuals with hyperglycemia. Our study emphasizes the necessity for continued research focusing on the benefits of the MED. Such efforts including the ongoing clinical trial will offer further insights into the role of MED in the clinical management of DKD.</p

    CD133-Positive Cells Might Be Responsible for Efficient Proliferation of Human Meningioma Cells

    Get PDF
    Owing to lack of appropriate model systems, investigations of meningioma biology have come to a stop. In this study, we developed a comprehensive digestion method and defined a culture system. Using this method and system, primary meningioma cells in conditioned suspension medium and a hypoxic environment could be amplified in spheres and were passaged for more than ten generations. Meningioma sphere cells were positive for meningioma cell markers and negative for markers of neural cell types. Importantly, we found the cells expressed the stem cell marker, CD133, but not nestin. All of the tumor sphere cell populations showed a slower degree of cell proliferation than that of human glioma cells and fetal neural stem cells (NSCs). Further studies showed that the proliferative rate was positively correlated with CD133 expression. The higher the CD133 expression, the faster the cell proliferation. With the increase in cell generations, the cell proliferation rate gradually slowed down, and CD133 expression also decreased. Single CD133+ cells rather than CD133− cells could form spheres. Thus, the results above indicated that those cells expressing CD133 in spheres might be stem-like cells, which may be responsible for efficient amplification of human meningioma cells. Decreased expression of CD133 may lead to the failure of long-term passaging

    In-situ growth of nitrogen-doped carbon nanotubes on MXene nanosheets for efficient sodium/potassium-ion storage

    Get PDF
    For game changing for future of large-scale energy storage technologies, sodium-ion and potassium-ion batteries provide a substitute to lithium-ion batteries. As an excellent candidate anode, MXene still suffers from the blockage of active sites caused by restacking of sheets. Herein, an in-situ decoration of MXene nanosheets with nitrogen-doped carbon nanotubes (CNTs) is introduced, to yield MXene@CNTs. The modification of nitrogen-doped CNTs not only prevents the restacking of MXene and increases ion accessibility but also improves the electrode’s overall conductivity, thereby enhancing electron conduction and ion diffusion kinetics significantly. Therefore, MXene@CNTs exhibits superior sodium/potassium-ion storage performance than pure MXene nanosheets. At 0.05 A g-1, it can deliver reversible capacities of 286 mAh g-1 for SIBs and 250 mAh g-1 for PIBs. This research illustrates the significance of the electrode architecture for electrochemical performances, and the in-situ growth strategy could provide some insight on searching for high-performance MXene-based anodes for SIBs and PIBs
    corecore