THERMAL BEHAVIOR STUDY AND DECOMPOSITION KINETICS OF SALBUTAMOL UNDER ISOTHERMAL AND NON-ISOTHERMAL CONDITIONS

The thermal decomposition of salbutamol (beta(2) - selective adrenoreceptor) was studied using differential scanning calorimetry (DSC) and thermogravimetry/derivative thermogravimetry (TG/DTG). It was observed that the commercial sample showed a different thermal profile than the standard sample caused by the presence of excipients. These compounds increase the thermal stability of the drug. Moreover, higher activation energy was calculated for the pharmaceutical sample, which was estimated by isothermal and non-isothermal methods for the first stage of the thermal decomposition process. For isothermal experiments the average values were E(act) = 130 kJ mol(-1) (for standard sample) and E(act) = 252 kJ mol(-1) (for pharmaceutical sample) in a dynamic nitrogen atmosphere (50 mL min(-1)). For non-isothermal method, activation energy was obtained from the plot of log heating rates vs. 1/T in dynamic air atmosphere (50 mL min(-1)). The calculated values were E(act) = 134 kJ mol(-1) (for standard sample) and E(act) (=) 139 kJ mol(-1) (for pharmaceutical sample).

Topology Optimized Design, Microfabrication and Characterization of Electro-Thermally Driven Microgripper

This article presents a systematic and logical study of the topology optimized design, microfabrication, and static/dynamic performance characterization of an electro-thermo-mechanical microgripper. The microgripper is designed using a topology optimization algorithm based on a spatial filtering technique and considering different penalization coefficients for different material properties during the optimization cycle. The microgripper design has a symmetric monolithic 2D structure which consists of a complex combination of rigid links integrating both the actuating and gripping mechanisms. The numerical simulation is performed by studying the effects of convective heat transfer, thermal boundary conditions at the fixed anchors, and microgripper performance considering temperature-dependent and independent material properties. The microgripper is fabricated from a 25 mm thick nickel foil using laser microfabrication technology and its static/dynamic performance is experimentally evaluated. The static and dynamic electro-mechanical characteristics are analyzed as step response functions with respect to tweezing/actuating displacements, applied current/power, and actual electric resistance. A microgripper prototype having overall dimensions of 1mm (L) X 2.5mm (W) is able to deliver the maximum tweezing and actuating displacements of 25.5 mm and 33.2 mm along X and Y axes, respectively, under an applied power of 2.32 W. Experimental performance is compared with finite element modeling simulation results.

Treatment of Aqueous Effluents Containing Phenol by the O(3), O(3)-UV, and O(3)-H(2)O(2) Processes: Experimental Study and Neural Network Modeling

In this work, the oxidation of the model pollutant phenol has been studied by means of the O(3), O(3)-UV, and O(3)-H(2)O(2) processes. Experiments were carried out in a fed-batch system to investigate the effects of initial dissolved organic carbon concentration, initial, ozone concentration in the gas phase, the presence or absence of UVC radiation, and initial hydrogen peroxide concentration. Experimental results were used in the modeling of the degradation processes by neural networks in order to simulate DOC-time profiles and evaluate the relative importance of process variables.

Design, construction and evaluation of a simple pressurized solvent extraction system

This work describes the construction and testing of a simple pressurized solvent extraction (PSE) system. A mixture of acetone:water (80:20), 80 ºC and 103.5 bar, was used to extract two herbicides (Diuron and Bromacil) from a sample of polluted soil, followed by identification and quantification by high-performance liquid chromatography coupled with diode array detector (HPLC-DAD). The system was also used to extract soybean oil (70 ºC and 69 bar) using pentane. The extracted oil was weighed and characterized through the fatty acid methyl ester analysis (myristic (< 0.3%), palmitic (16.3%), stearic (2.8%), oleic (24.5%), linoleic (46.3%), linolenic (9.6%), araquidic (0.3%), gadoleic (< 0.3%), and behenic (0.3%) acids) using high-resolution gas chromatography with flame ionization detection (HRGC-FID). PSE results were compared with those obtained using classical procedures: Soxhlet extraction for the soybean oil and solid-liquid extraction followed by solid-phase extraction (SLE-SPE) for the herbicides. The results showed: 21.25 ± 0.36% (m/m) of oil in the soybeans using the PSE system and 21.55 ± 0.65% (m/m) using the soxhlet extraction system; extraction efficiency (recovery) of herbicides Diuron and Bromacil of 88.7 ± 4.5% and 106.6 ± 8.1%, respectively, using the PSE system, and 96.8 ± 1.0% and 94.2 ± 3.9%, respectively, with the SLP-SPE system; limit of detection (LOD) and limit of quantification (LOQ) for Diuron of 0.012 mg kg-1 and 0.040 mg kg-1, respectively; LOD and LOQ for Bromacil of 0.025 mg kg-1 and 0.083 mg kg-1, respectively. The linearity used ranged from 0.04 to 1.50 mg L-1 for Diuron and from 0.08 to 1.50 mg L-1 for Bromacil. In conclusion, using the PSE system, due to high pressure and temperature, it is possible to make efficient, fast extractions with reduced solvent consumption in an inert atmosphere, which prevents sample and analyte decomposition.

3-Nitrophenol-4,4 '-bipyridyl N,N '-dioxide (2/1): a DFT study and CSD analysis of DPNO molecular complexes

The title 2:1 complex of 3-nitrophenol (MNP) and 4,4'-bipyridyl N, N'-dioxide (DPNO), 2C(6)H(5)NO(3)center dot C(10)H(8)N(2)O(2) or 2MNP center dot DPNO, crystallizes as a centrosymmetric three-component adduct with a dihedral angle of 59.40 (8)degrees between the planes of the benzene rings of MNP and DPNO (the DPNO moiety lies across a crystallographic inversion centre located at the mid-point of the C-C bond linking its aromatic rings). The complex owes its formation to O-H center dot center dot center dot O hydrogen bonds [O center dot center dot center dot O = 2.605 (3) angstrom]. Molecules are linked by intermolecular C-H center dot center dot center dot O and C-H center dot center dot center dot N interactions forming R(2)(1) (6) and R(2)(2) (10) rings, and R(6)(6) (34) and R(4)(4) (26) macro-rings, all of which are aligned along the [(1) over bar 01] direction, and R(2)(2) (10) and R(2)(1) (7) rings aligned along the [010] direction. The combination of chains of rings along the [(1) over bar 01] and [010] directions generates the three-dimensional structure. A total of 27 systems containing the DNPO molecule and forming molecular complexes of an organic nature were analysed and compared with the structural characteristics of the dioxide reported here. The N-O distance [1.325 (2) angstrom] depends not only on the interactions involving the O atom at the N-O group, but also on the structural ordering and additional three-dimensional interactions in the crystal structure. A density functional theory (DFT) optimized structure at the B3LYP/6-311G(d,p) level is compared with the molecular structure in the solid state.

Sertraline vs. ELectrical Current Therapy for Treating Depression Clinical Trial - SELECT TDCS: Design, rationale and objectives

Background: Despite significant advancements in psychopharmacology, treating major depressive disorder (MDD) is still a challenge considering the efficacy, tolerability, safety, and economical costs of most antidepressant drugs. One approach that has been increasingly investigated is modulation of cortical activity with tools of non-invasive brain stimulation - such as transcranial magnetic stimulation and transcranial direct current stimulation (tDCS). Due to its profile, tDCS seems to be a safe and affordable approach. Methods and design: The SELECT TDCS trial aims to compare sertraline vs. tDCS in a double-blinded, randomized, factorial trial enrolling 120 participants to be allocated to four groups to receive sertraline + tDCS, sertraline, tDCS or placebo. Eligibility criteria are moderate-to-severe unipolar depression (Hamilton Depression Rating Scale >17) not currently on sertraline treatment. Treatment will last 6 weeks and the primary outcome is depression change in the Montgomery-Asberg Depression Rating Score (MADRS). Potential biological markers that mediate response, such as BDNF serum levels, Val66Met BDNF polymorphism, and heart rate variability will also be examined. A neuropsychological battery with a focus on executive functioning will be administered. Discussion: With this design we will be able to investigate whether tDCS is more effective than placebo in a sample of patients free of antidepressants and in addition, we will be able to secondarily compare the effect sizes of sertraline vs. tDCS and also the comparison between tDCS and combination of tDCS and sertraline. (C) 2010 Elsevier Inc. All rights reserved.

Robotic Surgery: History and Teaching Impact

Context: The purpose of this article is to review the history of robotic surgery, its impact on teaching as well as a description of historical and current robots used in the medical arena. Summary of evidence: Although the history of robots dates back to 2000 years or more, the last two decades have seen an outstanding revolution in medicine, due to all the changes that robotic surgery has made in the way of performing, teaching and practicing surgery. Conclusions: Robotic surgery has evolved into a complete and self-contained field, with enormous potential for future development. The results to date have shown that this technology is capable of providing good outcomes and quality care for patients. (C) 2011 AEU. Published by Elsevier Espana, S.L. All rights reserved.

Fabry Disease in Hemodialysis Patients in Southern Brazil: Prevalence Study and Clinical Report

Background. Fabry disease (FD) is a lysosomal storage disorder caused by a deficiency of -Galactosidase A (-Gal A). Fabry nephropathy typically progresses throughout the fifth decade to end-stage renal disease (ESRD), requiring hemodialysis and/or kidney transplantation. Objective. To estimate the prevalence of FD among ESRD males on hemodialysis treatment in Rio Grande do Sul, the southernmost state of Brazil. Methods. Screening for -Gal A activity was performed by a dried blood spot (normal reference value: 1.5 nmoles/hour/mL). Positive screening results were confirmed by plasma -Gal A activity assay (reference value: 3.3 nmoles/hour/mL). Results. Five hundred fifty-eight male patients on hemodialysis were evaluated. Of these, only two had low -Gal A activity and were diagnosed with Fabry disease (0.36%). One of these, age 42, had left ventricular hypertrophy and renal manifestations of Fabry disease without the classic symptoms. The other, age 46, had the classical manifestations of angiokeratomas, acroparesthesias, hypohidrosis, and ocular opacities. Conclusions. Although the prevalence of Fabry disease was very low in our study (0.36%), routine screening of male hemodialysis patients would enable earlier identification of many other affected relatives in their families who might benefit from specific clinical treatment.