Bio-hydrogen production based on catalytic reforming of volatiles generated by cellulose pyrolysis: an integrated process for ZnO reduction and zinc nanostructures fabrication

The paper presents a process of cellulose thermal degradation with bio-hydrogen generation and zinc nanostructures synthesis. Production of zinc nanowires and zinc nanoflowers was performed by a novel processes based on cellulose pyrolysis, volatiles reforming and direct reduction of ZnO. The bio-hydrogen generated in situ promoted the ZnO reduction with Zn nanostructures formation by vapor–solid (VS) route. The cellulose and cellulose/ZnO samples were characterized by thermal analyses (TG/DTG/DTA) and the gases evolved were analyzed by FTIR spectroscopy (TG/FTIR). The hydrogen was detected by TPR (Temperature Programmed Reaction) tests. The results showed that in the presence of ZnO the cellulose thermal degradation produced larger amounts of H2 when compared to pure cellulose. The process was also carried out in a tubular furnace with N2 atmosphere, at temperatures up to 900 °C, and different heating rates. The nanostructures growth was catalyst-free, without pressure reduction, at temperatures lower than those required in the carbothermal reduction of ZnO with fossil carbon. The nanostructures were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM). The optical properties were investigated by photoluminescence (PL). One mechanism was presented in an attempt to explain the synthesis of zinc nanostructures that are crystalline, were obtained without significant re-oxidation and whose morphologies are dependent on the heating rates of the process. This route presents a potential use as an industrial process taking into account the simple operational conditions, the low costs of cellulose and the importance of bio-hydrogen and nanostructured zinc.

Functional and structural studies of the disulfide isomerase DsbC from the plant pathogen Xylella fastidiosa reveals a redox-dependent oligomeric modulation in vitro

Xylella fastidiosa is a Gram-negative bacterium that grows as a biofilm inside the xylem vessels of susceptible plants and causes several economically relevant crop diseases. In the present study, we report the functional and low-resolution structural characterization of the X. fastidiosa disulfide isomerase DsbC (XfDsbC). DsbC is part of the disulfide bond reduction/isomerization pathway in the bacterial periplasm and plays an important role in oxidative protein folding. In the present study, we demonstrate the presence of XfDsbC during different stages of X. fastidiosa biofilm development. XfDsbC was not detected during X. fastidiosa planktonic growth; however, after administering a sublethal copper shock, we observed an overexpression of XfDsbC that also occurred during planktonic growth. These results suggest that X. fastidiosa can use XfDsbC in vivo under oxidative stress conditions similar to those induced by copper. In addition, using dynamic light scattering and small-angle X-ray scattering, we observed that the oligomeric state of XfDsbC in vitro may be dependent on the redox environment. Under reducing conditions, XfDsbC is present as a dimer, whereas a putative tetrameric form was observed under nonreducing conditions. Taken together, our findings demonstrate the overexpression of XfDsbC during biofilm formation and provide the first structural model of a bacterial disulfide isomerase in solution. Structured digital abstract XfDsbC and XfDsbC bind by x ray scattering (View Interaction: 1, 2) XfDsbC and XfDsbC bind by molecular sieving (View interaction) XfDsbC and XfDsbC bind by comigration in non denaturing gel electrophoresis (View interaction) XfDsbC and XfDsbC bind by cross-linking study (View Interaction: 1, 2) XfDsbC and XfDsbC bind by dynamic light scattering (View Interaction: 1, 2)

Glyphosate impairs male offspring reproductive development by disrupting gonadotropin expression

Sexual differentiation in the brain takes place from late gestation to the early postnatal days. This is dependent on the conversion of circulating testosterone into estradiol by the enzyme aromatase. The glyphosate was shown to alter aromatase activity and decrease serum testosterone concentrations. Thus, the aim of this study was to investigate the effect of gestational maternal glyphosate exposure (50 mg/kg, NOAEL for reproductive toxicity) on the reproductive development of male offspring. Sixty-day-old male rat offspring were evaluated for sexual behavior and partner preference; serum testosterone concentrations, estradiol, FSH and LH; the mRNA and protein content of LH and FSH; sperm production and the morphology of the seminiferous epithelium; and the weight of the testes, epididymis and seminal vesicles. The growth, the weight and age at puberty of the animals were also recorded to evaluate the effect of the treatment. The most important findings were increases in sexual partner preference scores and the latency time to the first mount; testosterone and estradiol serum concentrations; the mRNA expression and protein content in the pituitary gland and the serum concentration of LH; sperm production and reserves; and the height of the germinal epithelium of seminiferous tubules. We also observed an early onset of puberty but no effect on the body growth in these animals. These results suggest that maternal exposure to glyphosate disturbed the masculinization process and promoted behavioral changes and histological and endocrine problems in reproductive parameters. These changes associated with the hypersecretion of androgens increased gonadal activity and sperm production.

Characterization of the motor performance in infants with a diagnosis of Cerebral Palsy in process of rehabilitation: the importance of the proactivity of caregivers

Introduction: The progress in technology, associated to the high survival rate in premature newborn infants in neonatal intensive care units, causes an increase in morbidity. Individuals with CP present complex motor alterations, with primary deficits of abnormal muscle tone affecting posture and voluntary movement, alteration of balance and coordination, decrease of force, and loss of selective motor control with secondary problems of contractures and bone deformities. Objective: The aim of this work is to describe the spontaneous movement and strategies that lead infants with cerebral palsy to move. Methods: Seven infants used to receive assistance at the Essential Stimulation Center of CIAM (Israeli Center for Multidisciplinary Support - Philanthropic Institution), with ages ranging between six and 18 months with diagnosis of Cerebral Palsy (CP) were assessed. Results: The results show the difficulty presented by the infants with respect to the spontaneous motor functions and the necessity of help from the caregiver in order to perform the functional activity (mobility). Prematurity prevails as the major risk factor among the complications. Conclusion: The child development can be understood as a product of the dynamic interactions involving the infant, the family, and the context. Thus, the social interactions and family environment in which the infant live may encourage or limit both the acquisition of skills and the functional independence.

Paracoccidioides brasiliensis lipids modulate macrophage activity via Toll-dependent or independent mechanisms

The macrophages are the first host cells that interact with the fungus Paracoccidioides brasiliensis, but the main mechanisms that regulate this interaction are not well understood. Because the role played by P. brasiliensis lipids in macrophage activation was not previously investigated, we aimed to assess the influence of diverse lipid fractions from P. brasiliensis yeasts in this process. The possible participation of TLR2 and TLR4 signaling was also evaluated using TLR2- and TLR4-defective macrophages. Four lipid-rich fractions were studied as follows: F1, composed by membrane phospholipids and neutral lipids, F2 by glycolipids of short chain, F3a by membrane glycoproteins anchored by glycosylphosphatidylinositol (GPI) groups, and F3b by glycolipids of long chain. All assayed lipid fractions were able to activate peritoneal macrophages and induce nitric oxide (NO) production. Importantly, the F1 and F3a fractions exerted opposite effects in the control of P. brasiliensis uptake and killing, but both fractions inhibited cytokines production. Furthermore, the increased NO production and expression of costimulatory molecules induced by F3a was shown to be TLR2 dependent although F1 used Toll-independent mechanisms. In conclusion, our work suggests that lipid components may play a role in the innate immunity against P. brasiliensis infection using Toll-dependent and independent mechanisms to control macrophage activation.

Temperature-dependent Raman study of thermal parameters in CdS quantum dots

We report on the strong temperature-dependent thermal expansion, alpha(D), in CdS quantum dots (QDs) embedded in a glass template. We have performed a systematic study by using the temperature-dependent first-order Raman spectra, in CdS bulk and in dot samples, in order to assess the size dependence of alpha(D), and where the role of the compressive strain provoked by the glass host matrix on the dot response is discussed. We report the Gruneisen mode parameters and the anharmonic coupling constants for small CdS dots with mean radius R similar to 2.0 nm. We found that gamma parameters change, with respect to the bulk CdS, in a range between 20 and 50%, while the anharmonicity contribution from two-phonon decay channel becomes the most important process to the temperature-shift properties.

On the generalized canonical equations of Hamilton for a time-dependent mass particle

Fundamental principles of mechanics were primarily conceived for constant mass systems. Since the pioneering works of Meshcherskii (see historical review in Mikhailov (Mech. Solids 10(5):32-40, 1975), efforts have been made in order to elaborate an adequate mathematical formalism for variable mass systems. This is a current research field in theoretical mechanics. In this paper, attention is focused on the derivation of the so-called 'generalized canonical equations of Hamilton' for a variable mass particle. The applied technique consists in the consideration of the mass variation process as a dissipative phenomenon. Kozlov's (Stek. Inst. Math 223:178-184, 1998) method, originally devoted to the derivation of the generalized canonical equations of Hamilton for dissipative systems, is accordingly extended to the scenario of variable mass systems. This is done by conveniently writing the flux of kinetic energy from or into the variable mass particle as a 'Rayleigh-like dissipation function'. Cayley (Proc. R Soc. Lond. 8:506-511, 1857) was the first scholar to propose such an analogy. A deeper discussion on this particular subject will be left for a future paper.

Biological evaluation of the bone healing process after application of two potentially osteogenic proteins: an animal experimental model

doi: 10.1111/j.1741-2358.2011.00526.x Biological evaluation of the bone healing process after application of two potentially osteogenic proteins: an animal experimental model Objective: The aim of this work was to analyse qualitatively and quantitatively the newly formed bone after insertion of rhBMP-2 and protein extracted from Hevea brasiliensis (P-1), associated or not with a carrier in critical bone defects created in Wistar rat calvarial bone, using histological and histomorphometrical analyses. Materials and methods: Eighty-four male Wistar rats were used, divided into two groups, according to the period of time until the sacrifice (2 and 6 weeks). Each one of these groups was subdivided into six groups with seven animals each, according to the treatments: (1) 5 mu g of pure rhBMP-2, (2) 5 mu g of rhBMP-2/monoolein gel, (3) pure monoolein gel, (4) 5 mu g of pure P-1, (5) 5 mu g of P-1/monoolein gel and (6) critical bone defect controls. The animals were euthanised and the calvarial bone tissue removed for histological and histomorphometrical analyses. Result and conclusion: The results showed an improvement in the bone healing process using the rhBMP-2 protein, associated or not with a material carrier in relation to the other groups, and this process demonstrated to be time dependent.

Geochronological constraints on the age of a Permo-Triassic impact event: U-Pb and Ar-40/Ar-39 results for the 40 km Araguainha structure of central Brazil

Impact cratering has been a fundamental geological process in Earth history with major ramifications for the biosphere. The complexity of shocked and melted rocks within impact structures presents difficulties for accurate and precise radiogenic isotope age determination, hampering the assessment of the effects of an individual event in the geological record. We demonstrate the utility of a multi-chronometer approach in our study of samples from the 40 km diameter Araguainha impact structure of central Brazil. Samples of uplifted basement granite display abundant evidence of shock deformation, but U/Pb ages of shocked zircons and the Ar-40/Ar-39 ages of feldspar from the granite largely preserve the igneous crystallization and cooling history. Mixed results are obtained from in situ Ar-40/Ar-39 spot analyses of shocked igneous biotites in the granite, with deformation along kink-bands resulting in highly localized, partial resetting in these grains. Likewise, spot analyses of perlitic glass from pseudotachylitic breccia samples reflect a combination of argon inheritance from wall rock material, the age of the glass itself, and post-impact devitrification. The timing of crater formation is better assessed using samples of impact-generated melt rock where isotopic resetting is associated with textural evidence of melting and in situ crystallization. Granular aggregates of neocrystallized zircon form a cluster of ten U-Pb ages that yield a "Concordia" age of 247.8 +/- 3.8 Ma. The possibility of Pb loss from this population suggests that this is a minimum age for the impact event. The best evidence for the age of the impact comes from the U-Th-Pb dating of neocrystallized monazite and Ar-40/Ar-39 step heating of three separate populations of post-impact, inclusion-rich quartz grains that are derived from the infill of miarolitic cavities. The Pb-206/U-238 age of 254.5 +/- 3.2 Ma (2 sigma error) and Pb-208/Th-232 age of 255.2 +/- 4.8 Ma (2 sigma error) of monazite, together with the inverse, 18 point isochron age of 254 +/- 10 Ma (MSWD = 0.52) for the inclusion-rich quartz grains yield a weighted mean age of 254.7 +/- 2.5 Ma (0.99%, 2 sigma error) for the impact event. The age of the Araguainha crater overlaps with the timing of the Permo-Triassic boundary, within error, but the calculated energy released by the Araguainha impact is insufficient to be a direct cause of the global mass extinction. However, the regional effects of the Araguainha impact event in the Parana-Karoo Basin may have been substantial. (C) 2012 Elsevier Ltd. All rights reserved.

Information-dependent processes in incubated and graduated technology-based companies: a comparative case study

Nowadays, competitiveness introduces new behaviors and leads companies to a discomforting situation and often to non adaptation to environmental requirements. A growing number of challenges associated with control of information in organizations with engineering activities can be seen, particularly, the growing amount of information subject to continuous changes. The innovative performance of an organization is directly proportional to its ability to manage information. Thus, the importance of information management is recognized by the search for more competent ways to face current demands. The purpose of this article was to analyze informationdependent processes in technology-based companies, through the four major stages of information management. The comparative method of cases and qualitative research were used. The research was conducted in nine technology-based companies which were incubated or recently went through the incubating process at the Technological Park of Sao Carlos, in the state of Sao Paulo. Among the main results, it was found that in graduated companies information management and its procedures were identified as more conscious and structured in contrast to those of the incubated companies.

Field dependent transition to the non-linear regime in magnetic hyperthermia experiments: Comparison between maghemite, copper, zinc, nickel and cobalt ferrite nanoparticles of similar sizes

Further advances in magnetic hyperthermia might be limited by biological constraints, such as using sufficiently low frequencies and low field amplitudes to inhibit harmful eddy currents inside the patient's body. These incite the need to optimize the heating efficiency of the nanoparticles, referred to as the specific absorption rate (SAR). Among the several properties currently under research, one of particular importance is the transition from the linear to the non-linear regime that takes place as the field amplitude is increased, an aspect where the magnetic anisotropy is expected to play a fundamental role. In this paper we investigate the heating properties of cobalt ferrite and maghemite nanoparticles under the influence of a 500 kHz sinusoidal magnetic field with varying amplitude, up to 134 Oe. The particles were characterized by TEM, XRD, FMR and VSM, from which most relevant morphological, structural and magnetic properties were inferred. Both materials have similar size distributions and saturation magnetization, but strikingly different magnetic anisotropies. From magnetic hyperthermia experiments we found that, while at low fields maghemite is the best nanomaterial for hyperthermia applications, above a critical field, close to the transition from the linear to the non-linear regime, cobalt ferrite becomes more efficient. The results were also analyzed with respect to the energy conversion efficiency and compared with dynamic hysteresis simulations. Additional analysis with nickel, zinc and copper-ferrite nanoparticles of similar sizes confirmed the importance of the magnetic anisotropy and the damping factor. Further, the analysis of the characterization parameters suggested core-shell nanostructures, probably due to a surface passivation process during the nanoparticle synthesis. Finally, we discussed the effect of particle-particle interactions and its consequences, in particular regarding discrepancies between estimated parameters and expected theoretical predictions. Copyright 2012 Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported License. [http://dx.doi. org/10.1063/1.4739533]

Effects of Black Leaf Streak Disease and Sigatoka Disease on fruit quality and maturation process of bananas produced in the subtropical conditions of southern Brazil

Banana fruits are harvested at the green-mature stage (pre-climacteric) in order to allow sufficient time for transport and marketing. The time between the harvest and the initiation of the natural ripening process is called green life (GL), which is closely correlated to physiological age. Sigatoka Disease (SD: also called yellow Sigatoka) and Black Leaf Streak Disease (BLSD; also called black Sigatoka) are the main foliar diseases affecting banana production. The aim of this work was to investigate the influence of these diseases on banana GL and postharvest behavior in subtropical conditions (southeastern Brazil). The results showed that both diseases shortened the banana's GL when compared to control bananas of the same physiological age. Moreover, fruits from infested plots showed higher values of CO2 (+100% for SD and +300% for BLSD) and C2H4 production (+30% for SD and +60% for BLSD) at the climacteric peak. BLSD caused 40% reduction in fruit weight. Fruits from plants with a high degree of SD or BLSD undergo an altered maturation process. (C) 2011 Elsevier Ltd. All rights reserved.

Relationships between gender, age, family conditions, physical and mental health, and social isolation of elderly caregivers

Background: In an aging population an increasing number of elderly caregivers will be called upon to provide care over a long period, during which time they will be burdened both by caregiving and by the physiological effects of their own aging. Among them there will be more aged male caregivers, who will probably be less prepared than women to become caregivers. The aim of this study was to investigate the relationship between caregivers' gender, age, family income, living arrangements and social support as independent variables, and depressive symptoms, comorbidities, level of frailty, grip strength, walking speed and social isolation, as dependent variables. Methods: 176 elderly people (123 women) were selected from a sample of a population-based study on frailty (n = 900), who had cared for a spouse (79.3%) and/or parents (31.4%) in the past five years (mean age = 71.8 +/- 4.86 years; mean monthly family income in minimum wages = 4.64 +/- 5.14). The study used questionnaires and self-report scales, grip strength and walking speed tests. Results: 65% of participants evaluated caregiving as being very stressful. Univariate analyses of regression showed low family income as a risk factor for depression; being female and low perceived social support as a risk for comorbidities; being 80 years of age and above for low grip strength; and being male for social isolation indicated by discontinuity of activities and social roles. In multivariate analyses of regression, poverty arose as a risk factor for depression and being female for comorbidities. Conclusions: Gender roles, age, income and social support interacted with physical and emotional health, and with the continuity of social participation of elderly caregivers. Special attention must be given to male caregivers.

Subthalamic deep brain stimulation modulates small fiber-dependent sensory thresholds in Parkinson's disease

The effects of deep brain stimulation of the subthalamic nucleus on nonmotor symptoms of Parkinson's disease (PD) rarely have been investigated. Among these, sensory disturbances, including chronic pain (CP), are frequent in these patients. The aim of this study was to evaluate the changes induced by deep brain stimulation in the perception of sensory stimuli, either noxious or innocuous, mediated by small or large nerve fibers. Sensory detection and pain thresholds were assessed in 25 PD patients all in the off-medication condition with the stimulator turned on or off (on- and off-stimulation conditions, respectively). The relationship between the changes induced by surgery on quantitative sensory testing, spontaneous CP, and motor abilities were studied. Quantitative sensory test results obtained in PD patients were compared with those of age-matched healthy subjects. Chronic pain was present in 72% of patients before vs 36% after surgery (P = .019). Compared with healthy subjects, PD patients had an increased sensitivity to innocuous thermal stimuli and mechanical pain, but a reduced sensitivity to innocuous mechanical stimuli. In addition, they had an increased pain rating when painful thermal stimuli were applied, particularly in the off-stimulation condition. In the on-stimulation condition, there was an increased sensitivity to innocuous thermal stimuli but a reduced sensitivity to mechanical or thermal pain. Pain provoked by thermal stimuli was reduced when the stimulator was turned on. Motor improvement positively correlated with changes in warm detection and heat pain thresholds. Subthalamic nucleus deep brain stimulation contributes to relieve pain associated with PD and specifically modulates small fiber-mediated sensations. (C) 2012 International Association for the Study of Pain. Published by Elsevier B. V. All rights reserved.

Exchange of disfluency with age from function to content words in Brazilian Portuguese speakers who do and do not stutter

The purpose of this study was to investigate the exchange of disfluencies from function words to content words with age in Brazilian Portuguese speakers who do and do not stutter. Ninety stuttering individuals and 90 controls, native speakers of Brazilian Portuguese, were divided into three age groups (children, adolescents and adults). The study method involved analyzing the occurrence of stuttering on content and function words based on spontaneous speech samples. Results indicated that children tend to be more disfluent on function words. With the increase in age, teenagers and adults who stutter presented a higher number of disfluencies on content words. These findings support the current literature, indicating that with the aging process, there is an exchange of disfluencies from function to content words. This shift in the disfluency pattern may account for a more advanced type of stuttering. The study also demonstrated that disfluencies in Portuguese speakers follow the same pattern of shifting from function to content words with age as for English speakers.