The Role of Polysorbate 80 and HPβCD at the Air-Water Interface of IgG Solutions

Purpose: To test the hypothesis of surface displacement as the underlying mechanism for IgG stabilization by polysorbates and HPβCD against surface-induced aggregation. Methods: Adsorption/desorption-kinetics of IgG-polysorbate 80/-HPβCD were monitored. Maximum bubble pressure method was used for processes within seconds from surface formation. Profile analysis tensiometry was applied over long periods and to assess surface rheologic properties. Additionally, the kinetics of adsorption, desorption and surface displacement was followed by a double-capillary setup of the profile analysis tensiometer, allowing drop bulk exchange. Results: Weak surface activity for HPβCD vs. much higher surface activity for polysorbate 80 was shown. Protein-displacement when exceeding a polysorbate 80 concentration close to the CMC and a lack of protein displacement for HPβCD was observed. The drop bulk exchange experiments show IgG displacement by polysorbate 80 independent of the adsorption order. In contrast, HPβCD coexists with IgG at the air-water interface when the surface layer is built from a mixed IgG-HPβCD-solution. Incorporation of HPβCD in a preformed IgG-surface-layer does not occur. Conclusions: The results confirm surface displacement as the stabilization mechanism of polysorbate 80, but refute the frequently held opinion, that HPβCD stabilizes proteins against aggregation at the air-water interface in a manner comparable to non-ionic surfactant

Prevalence

Background: Spontaneous bacterial pleuritis is a high mortality complication in cirrhotic patients with hydrothorax. Aim: To investigate the prevalence and risk factors for spontaneous bacterial pleuritis in cirrhotic patients with hydrothorax. Methods: Adult inpatients with liver cirrhosis and hydrothorax were enrolled. The severity of liver disease was assessed by the Model for End-Stage Liver Disease (MELD) score. Pleural fluid was analyzed [pH, polymorphonuclear (PMN) leucocyte count, total protein level, lactate dehydrogenase (LDH) level, glucose level, bacterial culture and cytology]. Spontaneous bacterial pleuritis was diagnosed by positive pleural fluid culture or, if negative, a pleural fluid PMN count >500 cells/μL without radiographic evidence of pneumonia. Results: Out of 98 cirrhotic patients with hydrothorax enrolled in the study; 14 (14.3%) fullfilled the criteria for the diagnosis of spontaneous bacterial pleuritis. Of those 14 patients; 9 were culture positive and 5 were culture negative. The other 84 did not have evidence of spontaneous bacterial pleuritis and were considered to have uncomplicated hydrothorax. Patients with spontaneous bacterial pleuritis had more severe liver diseases (MELD score), and higher rate of associated spontaneous bacterial peritonitis (SBP) and bacteraemia than patients with uncomplicated hydrothorax. Patients with spontaneous bacterial pleuritis had a significantly higher PMN count and a lower protein level in the pleural fluid. Conclusion: The prevalence of spontaneous bacterial pleuritis in the studied group of patients with hepatic hydrothorax was 14.3%. Patients with advanced liver disease, low pleural fluid protein, or SBP are at risk for spontaneous bacterial pleuritis

Unified Algorithm for Demand-Side Appliance Commitment

Recent energy efficiency and conservation programs have created an unprecedented demand for home energy management systems (HEMS) in the residential sector aimed at reducing electricity consumption and saving on electricity bills. This paper gives a brief review of the basic algorithms found in the literature for HEMS that target optimum scheduling for home appliances participating in demand response (DR) programs. The working principles, as well as the pros and the cons, of these algorithms are explained and analyzed. Then, a unified algorithm to manage the hourly power consumption of home appliances on a daily basis is suggested using two scenarios. The first scenario aims to simultaneously achieve dual utility/customer benefits while avoiding the individual drawbacks of each presented algorithm. The second scenario aims to actively involve DR customers in making the optimum decision regarding their appliances in the face of their dynamic desires. The proposed algorithm is generic in the sense that it has the ability to achieve three different objectives for dual utility/customer benefits. Moreover, the paper takes into consideration a range of constraints, such as load priority, customer preferences, utility request, and electricity dynamic pricing scheme. The essential goal of this algorithm is not only to curtail or control the power consumption of appliances but to also shift it to a better price period based on different tariff rates. The results reflect the effectiveness of the proposed algorithm, which extends the previous findings in the literature by considering a wider range of limitations applied on HEMS

The Association of XRCC1 Gene Polymorphisms and Chronic Hepatitis C Induced Insulin Resistance in Egyptian Patients

Chronic hepatitis C is implicated in insulin resistance (IR) susceptibility. An X-ray repair cross-complementing group 1 gene (XRCC1) is proposed to be a candidate gene for a study of IR susceptibility. So, this study aims to investigate the possible association of the XRCC1 gene polymorphisms with the risk of IR related to chronic hepatitis C virus (HCV) infection in Egyptian patients. In a case-control study, a total of 210 subjects, including 140 chronic HCV patients (87 patients with IR and 53 without IR) and 70 healthy controls, were included. Two genetic polymorphisms (c.1254C > T and c.1517G > C) of the XRCC1 gene were genotyped via the PCR-restriction fragment length polymorphism (PCR-RFLP) technique. The result of the current study revealed that these two single nucleotide polymorphisms (SNPs) have statistically significant influences on susceptibility to IR in chronic HCV infected Egyptian patients. It could be concluded that c.1254C > T, the TT genotype, CT/CC carriers as well as c.1517G > C, the CC genotype and GC/GG carriers might be associated with increased IR susceptibility. Moreover, T-allele of c.1254C > T and the C-allele of c.1517G > C genetic variants might influence the susceptibility