Tailoring the structure, composition, optical properties and catalytic activity of Ag-Au nanoparticles by the galvanic replacement reaction

This Letter reports on the synthesis of Ag-Au nanoparticles (NPs) with controlled structures and compositions via a galvanic replacement reaction between Ag NPs and AuCl4(aq)- followed by the investigation of their optical and catalytic properties. Our results showed the formation of porous walls, hollow interiors and increased Au content in the Ag-Au NPs as the volume of AuCl4(aq)- employed in the reaction was increased. These variations led to a red shift and broadening of the SPR peaks and an increase of up to 10.9-folds in the catalytic activity towards the reduction of 4-nitrophenol relative to Ag NPs. (C) 2012 Elsevier B.V. All rights reserved.

Replacement of fentanyl infusion by enteral methadone decreases the weaning time from mechanical ventilation: a randomized controlled trial

Introduction: Patients undergoing mechanical ventilation (MV) are frequently administered prolonged and/or high doses of opioids which when removed can cause a withdrawal syndrome and difficulty in weaning from MV. We tested the hypothesis that the introduction of enteral methadone during weaning from sedation and analgesia in critically ill adult patients on MV would decrease the weaning time from MV. Methods: A double-blind randomized controlled trial was conducted in the adult intensive care units (ICUs) of four general hospitals in Brazil. The 75 patients, who met the criteria for weaning from MV and had been using fentanyl for more than five consecutive days, were randomized to the methadone (MG) or control group (CG). Within the first 24 hours after study enrollment, both groups received 80% of the original dose of fentanyl, the MG received enteral methadone and the CG received an enteral placebo. After the first 24 hours, the MG received an intravenous (IV) saline solution (placebo), while the CG received IV fentanyl. For both groups, the IV solution was reduced by 20% every 24 hours. The groups were compared by evaluating the MV weaning time and the duration of MV, as well as the ICU stay and the hospital stay. Results: Of the 75 patients randomized, seven were excluded and 68 were analyzed: 37 from the MG and 31 from the CG. There was a higher probability of early extubation in the MG, but the difference was not significant (hazard ratio: 1.52 (95% confidence interval (CI) 0.87 to 2.64; P = 0.11). The probability of successful weaning by the fifth day was significantly higher in the MG (hazard ratio: 2.64 (95% CI: 1.22 to 5.69; P < 0.02). Among the 54 patients who were successfully weaned (29 from the MG and 25 from the CG), the MV weaning time was significantly lower in the MG (hazard ratio: 2.06; 95% CI 1.17 to 3.63; P < 0.004). Conclusions: The introduction of enteral methadone during weaning from sedation and analgesia in mechanically ventilated patients resulted in a decrease in the weaning time from MV.

Central leptin replacement enhances chemorespiratory responses in leptin-deficient mice independent of changes in body weight

Previous studies showed that leptin-deficient (ob/ob) mice develop obesity and impaired ventilatory responses to CO2 . In this study, we examined if leptin replacement improves chemorespiratory responses to hypercapnia (7 % CO2) in ob/ob mice and if these effects were due to changes in body weight or to the direct effects of leptin in the central nervous system (CNS). was measured via plethysmography in obese leptin-deficient- (ob/ob) and wild-type- (WT) mice before and after leptin (10 mu g/2 mu l day) or vehicle (phosphate buffer solution) were microinjected into the fourth ventricle for four consecutive days. Although baseline was similar between groups, obese ob/ob mice exhibited attenuated compared to WT mice (134 +/- 9 versus 196 +/- 10 ml min(-1)). Fourth ventricle leptin treatment in obese ob/ob mice significantly improved (from 131 +/- 15 to 197 +/- 10 ml min(-1)) by increasing tidal volume (from 0.38 +/- 0.03 to 0.55 +/- 0.02 ml, vehicle and leptin, respectively). Subcutaneous leptin administration at the same dose administered centrally did not change in ob/ob mice. Central leptin treatment in WT had no effect on . Since the fourth ventricle leptin treatment decreased body weight in ob/ob mice, we also examined in lean pair-weighted ob/ob mice and found it to be impaired compared to WT mice. Thus, leptin deficiency, rather than obesity, is the main cause of impaired in ob/ob mice and leptin appears to play an important role in regulating chemorespiratory response by its direct actions on the CNS.

Rice oil as a soybean oil replacement in weanling pig diets

The motivation for including oils in the diets of weanling pigs is to increase dietary energy density to meet the pigs' energy requirements. The purpose of this study was to determine the digestible and metabolizable energy values of semi-refined rice oil (RO) and refined soybean oil (SO) for weanling pigs (Experiment 1), as well as to evaluate how replacing SO with RO in weanling pig diets affects performance, intestinal histology, organ morphometry and the occurrence of diarrhea (Experiment 2). In Experiment 1,21 barrows, averaging 19.63 +/- 0.37 kg body weight (BW), were used in a randomized complete block design experiment, with seven replications per treatment and one pig per experimental unit (metabolism cage). The treatments consisted of a reference diet and two test diets. The test diets were obtained by using 90% of the reference diet and 10% of RO or SO. The experimental period consisted of a 7 days adaptation period, followed by a 5 days collection period of feces and urine. The values of the apparent digestible energy, apparent metabolizable energy and N-corrected apparent metabolizable energy of the oils were, respectively, 26.24, 25.78 and 26.01 MJ kg(-1) for RO and 31.74, 31.35 and 31.51 MJ kg(-1) for SO. In Experiment 2, 120 weaned pigs, castrated males and females, averaging 6.74 +/- 0.42 kg BW, were used in a randomized complete block design experiment, with eight replications per treatment and three pigs per experimental unit (pen) to evaluate the effects of five replacement levels of SO with RO in isonutritive weanling pig diets. The treatments were as follows: 4:0 basal diet with 4% of SO; 3:1 basal diet with 3% of SO and 1% of RO; 2:2 basal diet with 2% of SO and 2% of RO; 1:3 basal diet with 1% of SO and 3% of RO; and 0:4 basal diet with 4% of RO. No effects of the replacement levels were observed in the weanling pigs' performance, organ morphometry or in their occurrence of diarrhea. However, a quadratic effect on the villus width and a cubic effect on the villus height:crypt depth ratio were observed in the duodenum. Therefore, if the determined values of energy are used in the feed formulation, refined soybean oil can be replaced with semi-refined rice oil in weanling pig diets without affecting their growth performance. (C) 2011 Elsevier B.V. All rights reserved.

Toward the optimal dose metric in continuous renal replacement therapy

Purpose: There is no consensus on the optimal method to measure delivered dialysis dose in patients with acute kidney injury (AKI). The use of direct dialysate-side quantification of dose in preference to the use of formal blood-based urea kinetic modeling and simplified blood urea nitrogen (BUN) methods has been recommended for dose assessment in critically-ill patients with AKI. We evaluate six different blood-side and dialysate-side methods for dose quantification. Methods: We examined data from 52 critically-ill patients with AKI requiring dialysis. All patients were treated with pre-dilution CWHDF and regional citrate anticoagulation. Delivered dose was calculated using blood-side and dialysis-side kinetics. Filter function was assessed during the entire course of therapy by calculating BUN to dialysis fluid urea nitrogen (FUN) ratios q/12 hours. Results: Median daily treatment time was 1,413 min (1,260-1,440). The median observed effluent volume per treatment was 2,355 mL/h (2,060-2,863) (p<0.001). Urea mass removal rate was 13.0 +/- 7.6 mg/min. Both EKR (r(2)=0.250; p<0.001) and K-D (r(2)=0.409; p<0.001) showed a good correlation with actual solute removal. EKR and K-D presented a decline in their values that was related to the decrease in filter function assessed by the FUN/BUN ratio. Conclusions: Effluent rate (ml/kg/h) can only empirically provide an estimated of dose in CRRT. For clinical practice, we recommend that the delivered dose should be measured and expressed as K-D. EKR also constitutes a good method for dose comparisons over time and across modalities.

Retrospective Clinical Study of 988 Dual Acid-Etched Implants Placed in Grafted and Native Bone for Single-Tooth Replacement

Purpose: To evaluate the influence of sex, implant characteristics, and bone grafting on the survival rate of dual acid-etched (DAE) implants. Materials and Methods: Patients treated with internal-hex DAE implants for single-tooth replacement in a military dental clinic between January 2005 and December 2010 were included in this study. Clinical data related to implant characteristics, implant location, presence of grafted bone, and implant failures were collected. The primary outcome was implant loss. The survival rate was analyzed using the Kaplan-Meier method. Cox regression modeling was used to determine which factors would predict implant failure. Results: DAE implants were evaluated in a total of 988 patients (80.3% men). Twenty-four (2.4%) implants failed, most were cylindric (54.2%) with regular platforms (70.8%) and were 10 mm long (58.3%). The failure rate was 2.4% for the anterior maxilla, 3.3% for the posterior maxilla, 1.6% for the anterior mandible, and 2.0% for posterior mandible. The cumulative survival rate was 97.6%. The failure rate was 8.8% in implants placed after sinus augmentation, 7.3% in bone block-grafted areas, and 1.6% in native bone. Based on multivariable analysis (Cox regression), sinus augmentation and bone block grafting had a statistically significant effect on implant failure; the hazard ratios were 5.5 and 4.6, respectively. Conclusion: The results revealed that DAE implants had high survival rates, and no influence of sex, location, shape, diameter, or length on failure rates could be observed. However, a significant association was observed between failure and presence of bone graft in the implant area. Int J Oral Maxillofac Implants 2012;27:1243-1248

Rice husk derived waste materials as partial cement replacement in lightweight concrete

In this study rice husk ash (RHA) and broiler bed ash from rice husk (BBA), two agricultural waste materials, have been assessed for use as partial cement replacement materials for application in lightweight concrete. Physical and chemical characteristics of RHA and BBA were first analyzed. Three similar types of lightweight concrete were produced, a control type in which the binder was just CEMI cement (CTL) and two other types with 10% cement replacement with, respectively, RHA and BBA. All types of similar lightweight concrete were prepared to present the same workability by adjusting the amount of superplasticizer. Properties of concrete investigated were compressive and flexural strength at different ages, absorption by capillarity, resistivity and resistance to chloride ion penetration (CTH method) and accelerated carbonation. Test results obtained for 10% cement replacement level in lightweight concrete indicate that although the addition of BBA conducted to lower performance in terms of the degradation indicative tests, RHA led to the enhancement of mechanical properties, especially early strength and also fast ageing related results, further contributing to sustainable construction with energy saver lightweight concrete.

Enzyme replacement prevents enamel defects in hypophosphatasia mice

Hypophosphatasia (HPP) is the inborn error of metabolism characterized by deficiency of alkaline phosphatase activity, leading to rickets or osteomalacia and to dental defects. HPP occurs from loss-of-function mutations within the gene that encodes the tissue-nonspecific isozyme of alkaline phosphatase (TNAP). TNAP knockout (Alpl-/-, aka Akp2-/-) mice closely phenocopy infantile HPP, including the rickets, vitamin B6-responsive seizures, improper dentin mineralization, and lack of acellular cementum. Here, we report that lack of TNAP in Alpl-/- mice also causes severe enamel defects, which are preventable by enzyme replacement with mineral-targeted TNAP (ENB-0040). Immunohistochemistry was used to map the spatiotemporal expression of TNAP in the tissues of the developing enamel organ of healthy mouse molars and incisors. We found strong, stage-specific expression of TNAP in ameloblasts. In the Alpl-/- mice, histological, mu CT, and scanning electron microscopy analysis showed reduced mineralization and disrupted organization of the rods and inter-rod structures in enamel of both the molars and incisors. All of these abnormalities were prevented in mice receiving from birth daily subcutaneous injections of mineral-targeting, human TNAP at 8.2?mg/kg/day for up to 44 days. These data reveal an important role for TNAP in enamel mineralization and demonstrate the efficacy of mineral-targeted TNAP to prevent enamel defects in HPP. (C) 2012 American Society for Bone and Mineral Research.

Partial Replacement of omega-6 Fatty Acids With Medium-Chain Triglycerides, but Not Olive Oil, Improves Colon Cytokine Response and Damage in Experimental Colitis

Background: Soybean oil is rich in omega-6 fatty acids, which are associated with higher incidence and more severe cases of inflammatory bowel diseases. The authors evaluated whether partial replacement of soybean oil by medium-chain triglycerides (MCTs) or olive oil influenced the incidence and severity of experimental ulcerative colitis by using different parenteral lipid emulsions (LEs). Methods: Wistar rats (n = 40) were randomized to receive parenteral infusion of the following LE: 100% soybean oil (SO), 50% MCT mixed with 50% soybean oil (MCT/SO), 80% olive oil mixed with 20% soybean oil (OO/SO), or saline (CC). After 72 hours of infusion, acetic acid experimental colitis was induced. After 24 hours, colon histology and cytokine expression were analyzed. Results: SO was not significantly associated with overall tissue damage. MCT/SO was not associated with necrosis (P < .005), whereas OO/SO had higher frequencies of ulcer and necrosis (P < .005). SO was associated with increased expression of interferon-gamma (P = .005) and OO/SO with increased interleukin (IL)-6 and decreased tumor necrosis factor-alpha expression (P < .05). MCT/SO appeared to decrease IL-1 (P < .05) and increase IL-4 (P < .001) expression. Conclusions: Parenteral SO with high concentration of omega-6 fatty acids was not associated with greater tissue damage in experimental colitis. SO partial replacement with MCT/SO decreased the frequency of histological necrosis and favorably modulated cytokine expression in the colon; however, replacement with OO/SO had unfavorable effects. (JPEN J Parenter Enteral Nutr. 2012; 36: 442-448)

17 beta-Estradiol replacement in young, adult and middle-aged female ovariectomized rats promotes improvement of spatial reference memory and an antidepressant effect and alters monoamines and BDNF levels in memory- and depression-related brain areas

Clinical and experimental evidence suggest that estrogens have a major impact on cognition, presenting neurotrophic and neuroprotective actions in regions involved in such function. In opposite, some studies indicate that certain hormone therapy regimens may provoke detrimental effects over female cognitive and neurological function. Therefore, we decided to investigate how estrogen treatment would influence cognition and depression in different ages. For that matter, this study assessed the effects of chronic 17 beta-estradiol treatment over cognition and depressive-like behaviors of young (3 months old), adult (7 months old) and middle-aged (12 months old) reproductive female Wistar rats. These functions were also correlated with alterations in the serotonergic system, as well as hippocampal BDNF. 17 beta-Estradiol treatment did not influence animals' locomotor activity and exploratory behavior, but it was able to improve the performance of adult and middle-aged rats in the Morris water maze, the latter being more responsive to the treatment. Young and adult rats displayed decreased immobility time in the forced swimming test, suggesting an effect of 17 beta-estradiol also over such depressive-like behavior. This same test revealed increased swimming behavior, triggered by serotonergic pathway, in adult rats. Neurochemical evaluations indicated that 17 beta-estradiol treatment was able to increase serotonin turnover rate in the hippocampus of adult rats. Interestingly, estrogen treatment increased BDNF levels from animals of all ages. These findings support the notion that the beneficial effects of 17 beta-estradiol over spatial reference memory and depressive-like behavior are evident only when hormone therapy occurs at early ages and early stages of hormonal decline. (C) 2011 Elsevier B.V. All rights reserved.

Expression of VEGF and collagen using a latex biomembrane as bladder replacement in rabbits

Objective: To investigate the VEGF expression and collagen deposition using a latex biomembrane as bladder replacement in rabbits. Materials and Methods: After partial cystectomy, a patch of a non-vulcanized latex biomembrane (2 x 2 cm) was sewn to the bladder of rabbits with 5/0 monofilament polydioxanone sulfate sutures in a watertight manner. Groups of 5 animals were killed at 15, 45 and 90 days after surgery and the bladder was removed. Sections of 5 mu m were cut and stained with picrosirius-red in order to estimate the amount of extracellular matrix in the graft. To confirm the presence of VEGF in tissues, protein expression was determined by immunohistochemistry. Results: No death, urinary leakage or graft extrusion occurred in any group. All bladders showed a spherical shape. A progressive reduction in the amount of collagen occurred in the graft area and was negatively and linearly correlated with time (p < 0.001). VEGF expression was higher in grafted areas when compared to controls at 15 and 45 days after surgery and decreased with time (p < 0.001). Conclusion: The latex biomembrane as a matrix for partial bladder replacement in rabbits promotes temporary collagen deposition and stimulates the angiogenic process.

Small volume of hypertonic saline as the initial fluid replacement in experimental hypodynamic sepsis

Abstract Introduction We conducted the present study to examine the effects of hypertonic saline solution (7.5%) on cardiovascular function and splanchnic perfusion in experimental sepsis. Methods Anesthetized and mechanically ventilated mongrel dogs received an intravenous infusion of live Escherichia coli over 30 minutes. After 30 minutes, they were randomized to receive lactated Ringer's solution 32 ml/kg (LR; n = 7) over 30 minutes or 7.5% hypertonic saline solution 4 ml/kg (HS; n = 8) over 5 minutes. They were observed without additional interventions for 120 minutes. Cardiac output (CO), mean arterial pressure (MAP), portal and renal blood flow (PBF and RBF, respectively), gastric partial pressure of CO2 (pCO2; gas tonometry), blood gases and lactate levels were assessed. Results E. coli infusion promoted significant reductions in CO, MAP, PBF and RBF (approximately 45%, 12%, 45% and 25%, respectively) accompanied by an increase in lactate levels and systemic and mesenteric oxygen extraction (sO2ER and mO2ER). Widening of venous-arterial (approximately 15 mmHg), portal-arterial (approximately 18 mmHg) and gastric mucosal-arterial (approximately 55 mmHg) pCO2 gradients were also observed. LR and HS infusion transiently improved systemic and regional blood flow. However, HS infusion was associated with a significant and sustained reduction of systemic (18 ± 2.6 versus 38 ± 5.9%) and mesenteric oxygen extraction (18.5 ± 1.9 versus 36.5 ± 5.4%), without worsening other perfusional markers. Conclusion A large volume of LR or a small volume of HS promoted similar transient hemodynamic benefits in this sepsis model. However, a single bolus of HS did promote sustained reduction of systemic and mesenteric oxygen extraction, suggesting that hypertonic saline solution could be used as a salutary intervention during fluid resuscitation in septic patients.

Rice husk derived waste materials as partial cement replacement in lightweight concrete

In this study rice husk ash (RHA) and broiler bed ash from rice husk (BBA), two agricultural waste materials, have been assessed for use as partial cement replacement materials for application in lightweight concrete. Physical and chemical characteristics of RHA and BBA were first analyzed. Three similar types of lightweight concrete were produced, a control type in which the binder was just CEMI cement (CTL) and two other types with 10% cement replacement with, respectively, RHA and BBA. All types of similar lightweight concrete were prepared to present the same workability by adjusting the amount of superplasticizer. Properties of concrete investigated were compressive and flexural strength at different ages, absorption by capillarity, resistivity and resistance to chloride ion penetration (CTH method) and accelerated carbonation. Test results obtained for 10% cement replacement level in lightweight concrete indicate that although the addition of BBA conducted to lower performance in terms of the degradation indicative tests, RHA led to the enhancement of mechanical properties, especially early strength and also fast ageing related results, further contributing to sustainable construction with energy saver lightweight concrete.