Generalized correlation functions for conductance fluctuations and the mesoscopic spin Hall effect

We study the spin Hall conductance fluctuations in ballistic mesoscopic systems. We obtain universal expressions for the spin and charge current fluctuations, cast in terms of current-current autocorrelation functions. We show that the latter are conveniently parametrized as deformed Lorentzian shape lines, functions of an external applied magnetic field and the Fermi energy. We find that the charge current fluctuations show quite unique statistical features at the symplectic-unitary crossover regime. Our findings are based on an evaluation of the generalized transmission coefficients correlation functions within the stub model and are amenable to experimental test. DOI: 10.1103/PhysRevB.86.235112

Effect of hydrogen bond formation on the elastic molecular scattering: a case study with methanol

Rayleigh optical activities of small hydrogen-bonded methanol clusters containing two to five molecules are reported. For the methanol trimer, tetramer, and pentamer both cyclic and linear structures are considered. After the geometry optimizations, the dipole moments and the dipole polarizabilities (mean, interaction, and anisotropic components) are calculated using HF, MP2 and DFT (B3LYP, B3P86 and BH&HLYP) with aug-cc-pVDZ extended basis set. The polarizabilities are used to analyse the depolarization ratios and the Rayleigh scattering activities. The variations in the activity and in the depolarization for Rayleigh scattered radiation with the increase in the cluster size for both cyclic and linear structures are analysed.

Effect of pre-flaring and file size on the accuracy of two electronic apex locators

Objective: This ex vivo study evaluated the effect of pre-flaring and file size on the accuracy of the Root ZX and Novapex electronic apex locators (EALs). Material and methods: The actual working length (WL) was set 1 mm short of the apical foramen in the palatal root canals of 24 extracted maxillary molars. The teeth were embedded in an alginate mold, and two examiners performed the electronic measurements using #10, #15, and #20 K-files. The files were inserted into the root canals until the "0.0" or "APEX" signals were observed on the LED or display screens for the Novapex and Root ZX, respectively, retracting to the 1.0 mark. The measurements were repeated after the pre-flaring using the S1 and SX Pro-Taper instruments. Two measurements were performed for each condition and the means were used. Intra-class correlation coefficients (ICCs) were calculated to verify the intra-and inter-examiner agreement. The mean differences between the WL and electronic length values were analyzed by the three-way ANOVA test (p<0.05). Results: ICCs were high (>0.8) and the results demonstrated a similar accuracy for both EALs (p>0.05). Statistically significant accurate measurements were verified in the pre-flared canals, except for the Novapex using a #20 K-file. Conclusions: The tested EALs showed acceptable accuracy, whereas the pre-flaring procedure revealed a more significant effect than the used file size.

USE OF ADDITIVES IN THE WOOD BIODEGRADATION BY THE FUNGUS Ceriporiopsis subvermispora: EFFECT IN THE MANGANESE PEROXIDASE-DEPENDENT LIPID PEROXIDATION

USE OF ADDITIVES IN THE WOOD BIODEGRADATION BY THE FUNGUS Ceriporiopsis subvermispora: EFFECT IN THE MANGANESE PEROXIDASE-DEPENDENT LIPID PEROXIDATION. Ceriporiopsis subvermispora is a selective fungus in the wood delignification and the most promising in biopulping. Through the lipid peroxidation initiated by manganese peroxidase (MnP), free radicals can be generated, which can act in the degradation of lignin nonphenolic structures. This work evaluated the prooxidant activity (based in lipid peroxidation) of enzymatic extracts from wood biodegradation by this fungus in cultures containing exogenous calcium, oxalic acid or soybean oil. It was observed that MnP significant activity is required to promote lipid peroxidation and wood delignification. Positive correlation between prooxidant activity x MnP was observed up to 300 IU kg(-1) of wood.

Effect of cellulose physical characteristics, especially the water sorption value, on the efficiency of its hydrolysis catalyzed by free or immobilized cellulase

Cellulase, an enzymatic complex that synergically promotes the degradation of cellulose to glucose and cellobiose, free or adsorbed onto Si/SiO(2) wafers at 60 degrees C has been employed as catalyst in the hydrolysis of microcrystalline cellulose (Avicel), microcrystalline cellulose pre-treated with hot phosphoric acid (CP), cotton cellulose (CC) and eucalyptus cellulose (EC). The physical characteristics such as index of crystallinity (I(C)), degree of polymerization (DP) and water sorption values were determined for all samples. The largest conversion rates of cellulose into the above-mentioned products using free cellulase were observed for samples with the largest water sorption values; conversion rates showed no correlation with either IC or DP of the biopolymer. Cellulose with large water sorption value possesses large pore volumes, hence higher accessibility. The catalytic efficiency of immobilized cellulase could not be correlated with the physical characteristics of cellulose samples. The hydrolysis rates of the same cellulose samples with immobilized cellulase were lower than those by the free enzyme, due to the diffusion barrier (biopolymer chains approaching to the immobilized enzyme) and less effective contact between the enzyme active site and its substrate. Immobilized cellulase, unlike its free counterpart, can be recycled at least six times without loss of catalytic activity, leading to higher overall cellulose conversion. (C) 2011 Elsevier B.V. All rights reserved.

Effect of Genetic Variants Related to Lipid Metabolism as Risk Factors for Cholelithiasis After Bariatric Surgery in Brazilian Population

The manifestation of cholelithiasis after bariatric surgery may depend on genetic factors related to lipid metabolism, including apolipoprotein E (APOE) and cholesteryl ester transfer protein (CETP) gene polymorphisms. We investigated the association between APOE HhaI and CETP TaqIB polymorphisms [PCR-RFLP] and occurrence of cholelithiasis over up to 8 months of follow-up after gastroplasty to Roux-en-Y gastric bypass in 220 patients distributed in Group 1 (G1) 114 with cholelithiasis postoperatively and Group 2 (G2) 106 without cholelithiasis, including biochemical and anthropometric profiles analyses. In our series, the allelic and genotypic distributions of CETP TaqIB and APOE HhaI polymorphisms were similar in both groups (P > 0.05). The subgroup analysis evidenced that 54% of the patients from G1, APOE*4 allele carriers compared with APOE*3/3 carriers, presented altered low-density lipoprotein cholesterol (LDL cholesterol) serum levels (P = 0.022) before bariatric surgery. The B1 allele for CETP was associated to more quickly elevation of HDL cholesterol levels just in individuals without cholelitiasis (P < 0.0001). The multivariate logistic regression analysis demonstrates correlation between APOE*4 allele, higher total cholesterol (TC) serum levels and prediposition to cholelitiasis in preoperative period. However, the presence of postoperative cholelithiasis was not associated with altered lipid profile. The CETP TaqIB and APOE HhaI polymorphisms do not seem to have association with gallstones in the late postoperative bariatric surgery, considering that these genetic variants do not differ subgroups of patients who are eligible to routine prophylactic cholecystectomy, at least in Brazilian population.

Structural effect of cationic amphiphiles in diacetylenic photopolymerizable membranes

Liposomes have been an excellent option as drug delivery systems, since they are able of incorporating lipophobic and/or lipophilic drugs, reduce drug side effects, increase drug targeting, and control delivery. Also, in the last years, their use reached the field of gene therapy, as non-viral vectors for DNA delivery. As a strategy to increase system stability, the use of polymerizable phospholipids has been proposed in liposomal formulations. In this work, through differential scanning calorimetry (DSC) and electron spin resonance (ESR) of spin labels incorporated into the bilayers, we structurally characterize liposomes formed by a mixture of the polymerizable lipid diacetylenic phosphatidylcholine 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine (DC8,9PC) and the zwitterionic lipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), in a 1:1 molar ratio. It is shown here that the polymerization efficiency of the mixture (c.a. 60%) is much higher than that of pure DC8,9PC bilayers (c.a. 20%). Cationic amphiphiles (CA) were added, in a final molar ratio of 1:1:0.2 (DC8,9PC:DMPC:CA), to make the liposomes possible carriers for genetic material, due to their electrostatic interaction with negatively charged DNA. Three amphiphiles were tested, 1,2-dioleoyl-3-trimetylammonium-propane (DOTAP), stearylamine (SA) and trimetyl (2-miristoyloxietyl) ammonium chloride (MCL), and the systems were studied before and after UV irradiation. Interestingly, the presence of the cationic amphiphiles increased liposomes polymerization. MCL displaying the strongest effect. Considering the different structural effects the three cationic amphiphiles cause in DC8,9PC bilayers, there seem to be a correlation between the degree of DC8,9PC polymerization and the packing of the membrane at the temperature it is irradiated (gel phase). Moreover, at higher temperatures, in the bilayer fluid phase, more polymerized membranes are significantly more rigid. Considering that the structure and stability of liposomes at different temperatures can be crucial for DNA binding and delivery, we expect the study presented here contributes to the production of new carrier systems with potential applications in gene therapy. (C) 2012 Elsevier Ireland Ltd. All rights reserved.

DETERMINATION OF DICLOFENAC SODIUM IN RABBIT PLASMA BY HPLC/UV: EVALUATION AND CHARACTERIZATION OF ITS CRYSTALLINE FORMS, ANHYDROUS AND HYDRATE, ON THE ANTIPYRETIC EFFECT

Diclofenac sodium (DS) is a non-steroidal anti-inflammatory drug that is widely prescribed for the treatment of rheumatoid arthritis and post-surgery analgesia. The active pharmaceutical ingredient is the anhydrous form; however, it can also exist in hydrate form. In this context, knowing the properties of the solid state is important and relevant in the pharmaceutical area because they have a significant impact on the solubility, bioavailability, and chemical stability of the drugs. In the present study, data from XRPD, FTIR spectroscopy, and thermal analysis were used for the identification and characterization of DS forms (anhydrous and hydrate). An HPLC method was optimized to evaluate the plasma concentration of DS in rabbits. The optimized method exhibited good linearity over the range 0.1-60 mu g/mL with correlation coefficients of >0.9991. The mean recovery was 100%. Precision and accuracy were determined within acceptable limits. Finally, to compare the pharmacological properties of anhydrous and hydrate DS forms, we investigated their effects in the febrile response induced by lipopolysaccharide from E. coli in rabbits. The results show that the antipyretic effect of anhydrous and hydrate DS forms are similar.

Nitrate reduces the negative effect of UV radiation on photosynthesis and pigmentation in Gracilaria tenuistipitata (Rhodophyta): the photoprotection role of mycosporine-like amino acids

Photoprotection of the agarophyte red alga Gracilaria tenuistipitata against ultraviolet radiation (UVR) was investigated in algae submitted for 1 week to photosynthetically active radiation (PAR, 260 mu mol photons m(-2) s(-1)) or PAR + UVR (UV-A, 8.13 W m(-2) and UV-B, 0.42 W m(-2)) under different nitrogen concentrations: 0, 0.1, and 0.5 mM of NO3-. Photosynthetic pigments decreased during the time of the experiment mainly under low nitrogen supply and UVR. Incubation under high nitrogen supply (0.5 mM) sustained the photosynthetic levels over time. In contrast, mycosporine-like amino acids (MAAs) increased up to eightfold in the presence of UVR and 0.5 mM NO3-. Under PAR + UVR, maximal quantum yield was positively correlated to MAA abundance, whereas under PAR no correlation was found. The photosynthetic yield of algae cultivated during seven days under PAR + UVR was less affected by a 30-min exposure of high UVR (16 W m(-2)) and fully recovered after transferring to low PAR irradiances, whereas algae kept under PAR were more affected by UV exposure and no full recovery was observed. Growth rates decreased after three days in the presence of UVR and under low nitrate supply. However, these rates were similar when compared with treatments of PAR and PAR + UVR after seven days, with the exception of samples in 0 mM NO3-, indicating that the acclimation after one week's exposure is related to nitrate supply. In conclusion, the lowest negative effect of UVR on photosynthesis and growth rate in high N-supply-grown algae could be explained by the stimulation of photoprotection mechanisms, such as accumulation of MAAs. Photostimulation of MAA accumulation by UVR under high N supply was observed in G. tenuistipitata even after 20 years in culture without the induction of this photomorphogenic light signal.

A Poisson mixed model with nonnormal random effect distribution

In this paper, we propose a random intercept Poisson model in which the random effect is assumed to follow a generalized log-gamma (GLG) distribution. This random effect accommodates (or captures) the overdispersion in the counts and induces within-cluster correlation. We derive the first two moments for the marginal distribution as well as the intraclass correlation. Even though numerical integration methods are, in general, required for deriving the marginal models, we obtain the multivariate negative binomial model from a particular parameter setting of the hierarchical model. An iterative process is derived for obtaining the maximum likelihood estimates for the parameters in the multivariate negative binomial model. Residual analysis is proposed and two applications with real data are given for illustration. (C) 2011 Elsevier B.V. All rights reserved.

Gender Effect on Oral Volume Capacity

Studies have shown anatomical and functional differences between men and women with respect to the mouth, pharynx, upper esophageal sphincter, and esophagus. The aim of this investigation was to analyze the influence of gender, body mass index (BMI), age, and orofacial anthropometric measurements on the intraoral maximum volume capacity for liquid. The investigation included asymptomatic subjects, 56 females and 44 males, aged 19-53 years. The volunteers sucked water through a straw up to the maximum tolerated oral volume, which was greater in men (71.2 +/- A 15.0 ml) than in women (55.4 +/- A 13.4 ml). Age, BMI, height, and number of teeth had no influence on the intraoral tolerated volume. Anthropometric orofacial measurements were greater in men than in women. In individuals with height between 1.66 and 1.89 m, anthropometric orofacial measurements were greater in men than in women, and the tolerated intraoral volume was greater in men than in women. There was a positive correlation between orofacial measurements and intraoral maximum volume. In conclusion, men have the capacity to place a larger volume of water inside their mouth than women. This observation is associated with higher anthropometric orofacial measures, but not with age, number of teeth, height, or BMI.

Effect of the vanadium(V) concentration on the spectroscopic properties of nanosized europium-doped yttrium phosphates

Nanosized rare earth phosphovanadate phosphors (Y(P,V)O-4:Eu3+) have been prepared by applying the organic-inorganic polymeric precursors methodology. Luminescent powders with tetragonal structure and different vanadate concentrations (0%, 1%, 5%, 10%, 20%, 50%, and 100%, with regard to the phosphate content) were then obtained for evaluation of their structural and spectroscopic properties. The solids were characterized by scanning electron microscopy, X-ray diffractometry, vibrational spectroscopy (Raman and infrared), and electronic spectroscopy (emission, excitation, luminescence lifetimes, chromaticity, quantum efficiencies, and Judd-Ofelt intensity parameters). The solids exhibited very intense D-5(0) -> F-7(J) Eu3+ transitions, and it was possible to control the luminescent characteristics, such as excitation maximum, lifetime and emission colour, through the vanadium(V) concentration. The observed luminescent properties correlated to the characteristics of the chemical environments around the Eu3+ ions with respect to the composition of the phosphovanadates. The Eu3+ luminescence spectroscopy results indicated that the presence of larger vanadium(V) amounts in the phosphate host lattice led to more covalent and polarizable chemical environments. So, besides allowing for control of the luminescent properties of the solids, the variation in the vanadate concentration in the obtained YPO4:Eu3+ phosphors enabled the establishment of a strict correlation between the observable spectroscopic features and the chemical characteristics of the powders.

Evaluation of the effects of hyperbaric oxygen therapy for spinal cord lesion in correlation with the moment of intervention

Study design: Experimental, controlled, animal study. Objectives: To evaluate the functional effect of hyperbaric oxygen therapy administered shortly, one day after, and no intervention (control) in standardized experimental spinal cord lesions in Wistar rats. Setting: Sao Paulo, Brazil. Methods: In all, 30 Wistar rats with spinal cord lesions were divided into three groups: one group was submitted to hyperbaric oxygen therapy beginning half an hour after the lesion and with a total of 10 one-hour sessions, one session per day, at 2 atm; the second received the same treatment, but beginning on the day after the lesion; and the third received no treatment (control). The Basso, Beattie and Bresnahan scales were used for functional evaluation on the second day after the lesion and then weekly, until being killed 1 month later. Results: There were no significant differences between the groups in the functional analysis on the second day after the lesion. There was no functional difference comparing Groups 1 and 2 (treated shortly after or one day after) in any evaluation moment. On the 7th day, as well as on the 21st and 28th postoperative days, the evaluation showed that Groups 1 and 2 performed significantly better than the control group (receiving no therapy). Conclusion: Hyperbaric chamber therapy is beneficial in the functional recovery of spinal cord lesions in rats, if it is first administered just after spinal cord injury or within 24 h. Spinal Cord (2012) 50, 502-506; doi: 10.1038/sc.2012.16; published online 6 March 2012

Effect of image resolution manipulation in rearfoot angle measurements obtained with photogrammetry

The aim of this study was to investigate the influence of image resolution manipulation on the photogrammetric measurement of the rearfoot static angle. The study design was that of a reliability study. We evaluated 19 healthy young adults (11 females and 8 males). The photographs were taken at 1536 pixels in the greatest dimension, resized into four different resolutions (1200, 768, 600, 384 pixels) and analyzed by three equally trained examiners on a 96-pixels per inch (ppi) screen. An experienced physiotherapist marked the anatomic landmarks of rearfoot static angles on two occasions within a 1-week interval. Three different examiners had marked angles on digital pictures. The systematic error and the smallest detectable difference were calculated from the angle values between the image resolutions and times of evaluation. Different resolutions were compared by analysis of variance. Inter- and intra-examiner reliability was calculated by intra-class correlation coefficients (ICC). The rearfoot static angles obtained by the examiners in each resolution were not different (P > 0.05); however, the higher the image resolution the better the inter-examiner reliability. The intra-examiner reliability (within a 1-week interval) was considered to be unacceptable for all image resolutions (ICC range: 0.08-0.52). The whole body image of an adult with a minimum size of 768 pixels analyzed on a 96-ppi screen can provide very good inter-examiner reliability for photogrammetric measurements of rearfoot static angles (ICC range: 0.85-0.92), although the intra-examiner reliability within each resolution was not acceptable. Therefore, this method is not a proper tool for follow-up evaluations of patients within a therapeutic protocol.