Catalytic performance of texturally improved Al–Mg mixed oxides derived from emulsion-synthesized hydrotalcites

Mixed oxides of aluminum and magnesium derived from hydrotalcites were prepared by means of a sol–gel method mediated by an emulsified sol as pore template. The emulsion consisted of ethanol as the continuous phase and n-dodecane droplets as the dispersed phase, which was stabilized by the presence of the surfactant Pluronic P123. The use of such an emulsion was essential for obtaining materials with a porous structure that were assessed by mercury intrusion porosimetry and nitrogen physisorption. Additional characterization by NH₃ and CO₂ temperature programmed desorption confirmed that despite the enhancement of their textural properties, the number of acid and base sites was reduced in comparison to a reference and conventionally prepared Al–Mg mixed oxide, as a consequence of the depletion of surface hydroxyls during condensation of the precursors around the nonpolar droplets of the emulsion. Catalytic conversion of 2-propanol under conditions of controlled mass and heat diffusion on the texturally improved Al–Mg mixed oxides evidenced the preparation of a more effective catalyst than the poorly porous reference.

Mixed oxides of aluminum and magnesium derived from hydrotalcites that were prepared by means of a sol–gel method mediated by an emulsified sol as pore template.     

On the synergy between silver nanoparticles and doxycycline towards the inhibition of Staphylococcus aureus growth

In a previous paper (RSC Adv., 2015, 5, 66886–66893), we showed that the combination of silver nanoparticles (NanoAg) with doxycycline (DO) culminated in an increased bactericidal activity towards E. coli. Herein we further investigated the metabolic changes that occurred on Staphylococcus aureus upon exposure to NanoAg with the help of attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) coupled with multivariate data analysis. It has been discovered that the combination of DO with NanoAg produced metabolic changes in S. aureus that were not simply the overlap of the treatments with DO and NanoAg separately. Our results suggest that DO and NanoAg act synergistically to impede protein synthesis by the bacteria.

Silver nanoparticles conjugated with doxycycline act synergistically to halt S. aureus growth via inhibition of protein synthesis.     

Increased brain l‐arginine availability facilitates cutaneous heat loss induced by running exercise

The effects of increased brain availability of l ‐arginine (l ‐arg), a precursor for nitric oxide synthesis, on core body temperature (T_core) and cutaneous heat loss were evaluated in running rats. One week prior to the experiments, adult male Wistar rats received the following implants: a chronic guide cannula in the lateral cerebral ventricle and a temperature sensor in the abdominal cavity. On the day of the experiments, the rats were assigned to receive a 2‐μL intracerebroventricular injection of either NaCl (0.15 mol/L) or l ‐arg solution (0.825, 1.65 or 3.30 mol/L); T_core and tail skin temperature were measured while the rats ran at a speed of 18 m/min until they were fatigued. l ‐arginine induced a dose‐dependent reduction in the threshold T_core required for cutaneous heat loss (38.09 ± 0.20°C for 3.30‐mol/L l ‐arg vs 38.61 ± 0.10°C for saline; P < 0.05), which attenuated the exercise‐induced hyperthermia. Although the rats treated with l ‐arg presented a lower T_core at the end of exercise (~0.7°C lower after treatment with the highest dose), no changes in the time to fatigue were observed relative to the control trial. These results suggest that brain l ‐arg controls heat loss during exercise, most likely by modulating the sympathetic vasoconstrictor tonus to skin vessels. Furthermore, despite facilitating cutaneous heat loss mechanisms, increased brain l ‐arg availability did not enhance physical performance.     

Biochemical and immunohistochemical analysis of glycosaminoglycans in inflamed and non-inflamed intestinal mucosa of patients with Crohn’s disease

OBJECTIVES: Changes in extracellular matrix glycosaminoglycans (GAGs) of the intestinal mucosa have been associated with inflammatory bowel disease. The aim of the present study was to follow the changes in GAGs metabolism during the progression from non-inflamed to inflamed intestinal colon of patients with Crohn's disease (CD), using direct biochemical analysis and specific immunohistochemistry against chondroitin/dermatan sulfate and heparan sulfate. DESIGN AND METHODS: The content of GAGs from inflamed and non-inflamed colon of eight patients with active CD was estimated by uronic acid per dry weight of tissue and analyzed by agarose gel electrophoresis and ion-exchange chromatography. Intestinal sections were stained using antibodies against dermatan sulfate/chondroitin 4-sulfate (DS/CS), heparan sulfate (HS), and ICAM-1 (CD54), and analyzed by confocal microscopy. RESULTS: There was a reduction in the amount of GAGs in the non-inflamed colon of patients with CD. In the inflamed colon, HS, CS and DS showed increased concentrations compared with the non-inflamed colon. GAGs showed a diffuse distribution in the lamina propria and in the basement membrane of both inflamed and non-inflamed mucosa of patients with CD. CONCLUSION: We observed a marked reduction in GAGs with altered patterns of distribution in the non-inflamed colon of patients with CD. The increase in the synthesis of GAGs observed in the inflamed colon may be a compensatory mechanism for the restoration of the integrity of the intestinal mucosa.     

First report and molecular characterization of hepatitis E virus infection in renal transplant recipients in Brazil

Hepatitis E virus (HEV) causes acute and chronic hepatitis in organ transplant recipients. Serological evidence for HEV infection has been discovered in various population groups in Brazil, and a single acute case has been confirmed. To date, however, no cases of HEV infection in immunocompromised patients have been reported in Brazil. This study aimed to identify and characterize hepatitis E cases in renal transplant recipients in Brazil. A retrospective study was performed on 96 serum samples from renal transplant recipients with unexplained liver enzymes elevation. Three confirmed cases of HEV infection were identified that lacked seroconversion to HEV IgG antibodies. The prevalence of HEV in these patients was 3.1%. Using a sequence analysis of a 304‐nucleotide fragment within ORF2, the strains were classified as genotype 3 with a low percent identity to previously characterized strains. This is the first report of hepatitis E infection in renal transplant recipients in Brazil, and the data indicate that a novel genotype 3 subvariant may be present and that further investigation is necessary to characterize the circulating HEV strains. In this setting, HEV infection should be considered as a potential cause of abnormal liver tests of unknown origin. J. Med. Virol. 85:615–619, 2013. © 2013 Wiley Periodicals, Inc.     

The COVID-19 anxiety syndrome and selective attentional bias towards COVID-19-related stimuli in UK residents during the 2020–2021 pandemic

The psychological and social effects of the COVID-19 pandemic are pervasive, and there is potential for a long-lasting impact on mental health. In the current study, we sought to provide, in a representative sample of UK residents during the third COVID-19 lockdown in February 2021, further evidence for the validation of the COVID-19 anxiety syndrome construct. We did this by evaluating the COVID-19 anxiety syndrome against measures of personality, health anxiety and COVID-19 anxiety in predicting levels of generalized anxiety and depression and by examining whether increased health anxiety and COVID-19 psychological distress (COVID-19 anxiety and COVID-19 anxiety syndrome) scores were associated with increased attentional bias to COVID-19-related stimuli. A series of correlation analyses revealed that neuroticism, health anxiety, COVID-19 anxiety and COVID-19 anxiety syndrome scores were positively and significantly correlated with generalized anxiety and depression scores and that the perseveration component of the COVID-19 anxiety syndrome predicted generalized anxiety and depression scores independently of age, gender, conscientiousness, openness, health anxiety and COVID-19 anxiety. Furthermore, results indicated that only the total COVID-19 anxiety syndrome score and the scores on the avoidance and perseveration components were positively and significantly correlated with attentional bias indices. More specifically, the general attentional bias index was only shown to be positively and significantly correlated with the total COVID-19 anxiety syndrome score and its perseveration component, while slowed disengagement was only shown to be negatively and significantly correlated with the total COVID-19 anxiety syndrome score and its avoidance component. The implications of these findings are discussed.     

The effect of desire thinking on facilitating beliefs in alcohol use disorder: An experimental investigation

Permissive beliefs relate to the acceptability of engaging in alcohol use in spite of obvious potential negative consequences. They are considered the most proximal and precipitating cognitive factor in the decision to use alcohol and/or the activation of strategies to obtain it. Recent research suggested that ‘desire thinking’ may be involved in the escalation of craving and addictive behaviours and can play a role in strengthening permissive beliefs. The current study tested whether the induction of desire thinking would have a stronger effect on rate of conviction in permissive beliefs compared to a control cognitive response in the form of neutral thinking and whether this effect would be specific for patients with alcohol use disorder (AUD). Thirty AUD patients and 30 social drinkers (SD) were randomly allocated to two thinking manipulation tasks (desire thinking and neutral thinking). Current permissive beliefs were measured before and after manipulation and after a resting phase. Findings showed that desire thinking increased the level of current permissive beliefs after manipulation relative to the neutral thinking condition for the AUD group but not for the SD group. This effect was not purely dependent on the concurrent level of perceived craving. This study supports a causal relationship between the induction of desire thinking and rate of conviction in permissive beliefs and highlights the relevance of targeting desire thinking in the treatment for AUD patients.