Research progress of CO2 oxidative dehydrogenation of propane to propylene over Cr-free metal catalysts.

CO2-assisted oxidative dehydrogenation of propane (CO2-ODHP) is an attractive strategy to offset the demand gap of propylene due to its potentiality of reducing CO2 emissions, especially under the demands of peaking CO2 emissions and carbon neutrality. The introduction of CO2 as a soft oxidant into the reaction not only averts the over-oxidation of products, but also maintains the high oxidation state of the redox-active sites. Furthermore, the presence of CO2 increases the conversion of propane by coupling the dehydrogenation of propane (DHP) with the reverse water gas reaction (RWGS) and inhibits the coking formation to prolong the lifetime of catalysts via the reverse Boudouard reaction. An effective catalyst should selectively activate the C-H bond but suppress the C-C cleavage. However, to prepare such a catalyst remains challenging. Chromium-based catalysts are always applied in industrial application of DHP; however, their toxic properties are harmful to the environment. In this aspect, exploring environment-friendly and sustainable catalytic systems with Cr-free is an important issue. In this review, we outline the development of the CO2-ODHP especially in the last ten years, including the structural information, catalytic performances, and mechanisms of chromium-free metal-based catalyst systems, and the role of CO2 in the reaction. We also present perspectives for future progress in the CO2-ODHP.

[Lower respiratory tract infection caused by influenza virus A and influenza virus B in Wenzhou, China: a clinical analysis of 366 children].

OBJECTIVE: To compare the epidemiological and clinical features of lower respiratory tract infection (LRTI) caused by influenza virus A (IVA) and influenza virus B (IVB) in children. METHODS: The clinical data of 366 children with LRTI caused by influenza virus (IV), who were hospitalized in Yuying Children′s Hospital of Wenzhou Medical University between 2010 and 2014, were analyzed retrospectively, and there were 272 cases caused by IVA and 94 cases caused by IVB. RESULTS: IV was mainly prevalent from December to March of the next year, with the predominance of IVA. There were small peaks of IVA prevalence in July or September every other year, and IVB was prevalent from December to March of the next year every other year. The children with LRTI caused by IVA alone had a significantly higher white blood cell (WBC) count and significantly higher percentages of children with increased WBC, abnormal serum sodium, and abnormal serum potassium than those caused by IVB alone (P<0.05). However, there were no significant differences in age, sex, underlying diseases, clinical manifestations, and co-infection rate with bacteria or atypical pathogens between the two groups (P>0.05). The rate of co-infection with respiratory syncytial virus (RSV) was significantly higher in the IVB group than in the IVA group (P<0.01). CONCLUSIONS: IVA is prevalent in winter and spring every year and has small peaks in summer every other year, while IVB is prevalent in winter and spring every other year. Compared with IVB, IVA causes more cases of increased WBC and electrolyte disturbance. The children infected with IVB are more likely to be co-infected with RSV. The children with LRTI caused by IVA and IVB have similar clinical manifestations.

Band offsets of non-polar A-plane GaN/AlN and AlN/GaN heterostructures measured by X-ray photoemission spectroscopy.

The band offsets of non-polar A-plane GaN/AlN and AlN/GaN heterojunctions are measured by X-ray photoemission spectroscopy. A large forward-backward asymmetry is observed in the non-polar GaN/AlN and AlN/GaN heterojunctions. The valence-band offsets in the non-polar A-plane GaN/AlN and AlN/GaN heterojunctions are determined to be 1.33 ± 0.16 and 0.73 ± 0.16 eV, respectively. The large valence-band offset difference of 0.6 eV between the non-polar GaN/AlN and AlN/GaN heterojunctions is considered to be due to piezoelectric strain effect in the non-polar heterojunction overlayers.

The -2T/C polymorphism in the adrenocorticotropin receptor gene affects stress perception of patients with alopecia areata.

BACKGROUND: Altered hypothalamic-pituitary-adrenal (HPA) axis response involved in the pathogenesis of stress-associated alopecia areata (AA) has been reported. A novel polymorphism -2T>C of the adrenocorticotropin receptor (ACTHR) can result in an insufficient HPA response to stress; therefore, the functional polymorphism may underlie a role in stress-associated AA. OBJECTIVE: To investigate the relationship between psychosocial factors and the risk of developing AA and to detect the association between the -2T>C polymorphism of ACTHR and AA. METHODS: Stressful situations were evaluated using Holmes and Rahe's social readjustment rating scale. The ACTHR -2T>C polymorphism was examined in 263 patients with AA and 241 controls. RESULTS: Significant elevation of psychological stress experienced by some patients with AA compared with controls (Z = 6.628, P < 0.01). The frequency of the ACTHR C allele showed a significant difference between patients with AA and controls (P = 0.004). Allele C is the risk allele with a dominant model as the -2C allele occurred more often in patients with AA (P = 0.001). There were significant differences between patients with AA with a severe stress attack versus patients with AA with no obvious stress (P < 0.001), whereas the genotype frequencies were not correlated with the type, duration of disease, and age at onset. Notably, the C allele carrier was significantly associated with stress risk in both AA and controls (P = 0.002, OR = 1.576, 95% CI: 1.148-2.162; P = 0.042, OR = 1.529, 95% CI: 1.022-2.288). CONCLUSIONS: These findings suggest AA in some patients may be associated with stress. The ACTHR gene -2T>C variant may be one important factor that influences stress perception of patients with AA.

An implication for post-transcriptional control: reciprocal changes of melanocortin receptor type 2 mRNA and protein expression in alopecia areata.

Alopecia areata (AA) is a hair follicle-specific autoimmune disease that is inherited genetically but triggered environmentally. Stress response is believed to play a role in the pathogenesis of AA. The hypothalamic-pituitary-adrenal axis (HPA axis), known as the stress axis, plays a cardinal role in the stress response. Growing evidence demonstrates that stress responses are under the control of both the central and peripheral nervous systems. Skin and hair follicles display peripheral HPA axis-like signaling systems. Some studies have revealed that a modified HPA axis, which is characterized by enhanced CRH/CRHR and insufficient glucocorticoid, is involved in the pathology of AA, suggesting that the paradoxical expression differs from that of normal control and should be further examined. Because adrenocorticotropic hormone (ACTH) is an intermediary in the HPA axis, MC2R, which specifically binds ACTH, may be important in the stress response of skin. Therefore, we investigated the gene and protein expression of MC2R in AA lesions and tried to elucidate the connection between HPA axis regulation, MC2R and AA. Reciprocal changes in MC2R mRNA and proteins in human AA were observed in our study; while mRNA levels were higher in lesions from AA patients compared with scalp tissues from normal controls, protein levels of MC2R were lower. The paradoxical expression of MC2R gene and protein levels coincided with evidence that over-responsive HPA activity coexists with a deficient HPA response in AA. We hypothesized that the HPA axis response in human AA may be the following: stressors first activate excess CRH/CRHR to produce increased ACTH, which up-regulates the expression of MC2R mRNA, but the stress response cannot create sufficient cortisol when the binding of ACTH/MC2R is deficient due to decreased MC2R protein. This hypothesis rationally clarifies the changed HPA axis in human AA and highlights the importance of MC2R in the pathogenesis of AA. The inconsistent expression of protein and mRNA implicates post-transcriptional control of human MC2R gene expression as found in murine MC2R gene.

Melanocortin receptor type 2 (MC2R, ACTH receptor) expression in patients with alopecia areata.

Human skin expresses elements of the hypothalamo-pituitary-adrenal (HPA) axis that function as a local stress response system. Because adrenocorticotropic hormone (ACTH) is an intermediate in the HPA axis from corticotropin-releasing hormone (CRH) signal to cortisol secretion, MC2R that binds only ACTH may be important in the stress response of skin. We investigated the local expression of MC2R by immunohistochemistry to identify the role of ACTH/MC2R in stress-associated alopecia areata (AA). MC2R appeared to be highly compartmentalized in scalp skin including the epidermal cells of hair follicles and epidermis, sebaceous and eccrine glands, as well as dermal fibroblasts. The expression of MC2R was lower in AA lesions than in normal scalp tissue in almost all scalp skin cells, especially in epithelial cells. These findings demonstrate that MC2R expression is aberrant in AA and suggest a deficit in ACTH/MC2R activity may play an important role in the pathophysiology of AA.

[Viral etiology of acute respiratory infection in children from Wenzhou between 2007 and 2008].

OBJECTIVE: To study the viral etiology of acute respiratory infection (ARI)in children from Wenzhou, Zhejiang between 2007 and 2008. METHODS: The nasopharyngeal aspirate samples were obtained from 5 097 hospitalized children with ARI. Seven common respiratory viruses, including respiratory syncytial virus (RSV), influenza virus A and B, parainfluenza viruses 1, 2 and 3 and adenovirus, were detected using direct immunofluorescence. RESULTS: Viral agents were identified in 2 209 cases (43.3%).Of the 2 209, RSV was the most frequent (78.1%), followed by parainfluenza 3 (12.4%), influenza virus A (3.0%), adenovirus (2.8%), parainfluenza 1 (1.7%), influenza B (0.5%) and parainfluenza 2 (0.3%). The infants at ages of <3 months and <6 months had higher detection rate of viruses (53.6% and 49.2%, respectively). A highest detection rate of viruses was found in winter. CONCLUSIONS: RSV is the leading pathogen of ARI in children from Wenzhou, Zhejiang between 2007 and 2008. The children at age of less than 6 months are susceptible to respiratory viruses. The viral activity peaks in winter.

Erratum to: Binding Energy and Spin-Orbit Splitting of a Hydrogenic Donor Impurity in AlGaN/GaN Triangle-Shaped Potential Quantum Well.

[This corrects the article DOI: 10.1007/s11671-009-9398-3.].

Binding Energy and Spin-Orbit Splitting of a Hydrogenic Donor Impurity in AlGaN/GaN Triangle-Shaped Potential Quantum Well.

In the framework of effective-mass envelope function theory, including the effect of Rashba spin-orbit coupling, the binding energy E(b) and spin-orbit split energy Г of the ground state of a hydrogenic donor impurity in AlGaN/GaN triangle-shaped potential heterointerface are calculated. We find that with the electric field of the heterojunction increasing, (1) the effective width of quantum well W̅ decreases and (2) the binding energy increases monotonously, and in the mean time, (3) the spin-orbit split energy Г decreases drastically. (4) The maximum of Г is 1.22 meV when the electric field of heterointerface is 1 MV/cm.

[Treatment of calcaneal interarticular fracture by open reduction and internal fixation].

OBJECTIVE: To investigate the clinical outcome of open reduction and internal fixation of calcaneal interarticular fractures. METHODS: From August 1998, 38 calcanneal interarticular fractures in 35 cases, including 8 of type II, 14 of type III and 16 of type IV according to Sander's classification, were treated by open reduction to restore the posterior articular facet, subtalar facet, Bohler angle and Gissane's angle, following internal fixation by plastic titanic alloy plate. Thirty-three calcanneal interarticular fractures were followed up for 6 to 22 months, 12.3 months on average; and the healing time and joint function were evaluated according to Maryland Foot Score System. RESULTS: The average healing time of fracture was 7.1 weeks, ranging from 5 to 12 weeks; and the joint function was excellent in 18 calcanneus, good in 13 calcanneus, and the satisfactory rate was 93.9%. CONCLUSION: Open reduction and internal fixation with plastic titanium plate is a good choice for calcanel interarticular fractures.