Relationship between calcium intake and body mass index in adolescents

Epidemiologic and experimental data support thee possibility that dietary calcium intake plays a role in human body weight regulation. The aim of the present study was to evaluate calcium intake and its relationship with body mass index (BMI) in adolescents. Weight, height, 3-day food record and a food frequency questionnaire were collected among all adolescents participants at the Outpatient Clinic for Adolescents at the Federal University of Sao Paulo between 2001 and 2003. The statistical analysis comprised Chi-square, Student's T-test, Pearson correlation and linear regression. One-hundred and twenty-one adolescents were studied (62.8% female), with a mean age of 14.9 +/- 2.2 years old. Mean energy and calcium intakes were 1729.9 +/- 557.8 kcal/day and 598.2 +/- 287.9 mg/day respectively, with no significant statistical differences between sex or age. Almost ninety-eight percent of adolescents presented a mean calcium intake lower than proposed values. Calcium intake adjusted for energy presented a significant negative correlation with body weight (r=-0.194, p=0.03) and BMI (r=-0.185, p=0.04). Furthermore, adolescents in the lowest quartile of calcium intake presented higher BMI (29.7 +/- 7.4 kg/m2) than adolescents in the highest calcium quartile. These results indicated a dietary calcium intake lower than recommendations for this life stage, and a contribution of this mineral in the body mass index.     

The structure of distress following trauma: Posttraumatic stress disorder, major depressive disorder, and generalized anxiety disorder.

The current report used confirmatory factor analysis to examine the latent structures of both key features and associated symptoms of three disorders that commonly develop following a traumatic event: posttraumatic stress disorder (PTSD), major depressive disorder (MDD), and generalized anxiety disorder (GAD). Participants were 228 motor-vehicle accident survivors who sought treatment for emotional difficulties. PTSD, MDD, and GAD were assessed with a combination of self-report and interview-based measures. The results of construct level analyses suggested that PTSD, MDD, and GAD are distinguishable but highly correlated disorders following a traumatic event. Symptom level analyses supported a model where the Reexperiencing, Avoidance, and Hypervigilance factors were subsumed under the PTSD construct. However, in this model the Dysphoria factor was a higher order construct correlated with the PTSD, MDD, and GAD factors, suggesting that the Dysphoria cluster may not be unique to PTSD. Diagnostic and theoretical implications of these results are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of Brazilian Geographic Region and Organic Agriculture on the Composition and Crystallization Properties of Cocoa Butter

Cocoa butter (CB) is the most important ingredient in chocolate and represents the biggest share in the continuous phase of this product. The accurate composition of CB depends, among other factors, on the genetic characteristics of the cocoa tree, its agricultural handling and the farming region's climate. The influences of the cocoa‐producing region in Brazil and the agricultural cultivation method on the composition and crystallization properties of CB are presented in this article. Raw CB was extracted from fruits cultivated in six main Brazilian states using two agricultural methods, organic and conventional. The samples were evaluated according to fatty acids, triacylglycerol composition, solid fat content, consistency, melting behavior and isothermal crystallization. The wide range of cocoa‐producing regions in Brazil causes the distinct characteristics of the chemical composition and crystallization behavior of the CB, attributes that affect the quality of products using this raw material. Differences in consistency, hardness and crystallization parameters, among others, were observed. The results showed the great potential of using Brazilian CB with similar features to those of African and Asian origin, considered more appropriate for use in chocolates. However, no clear tendency concerning the agricultural method was found.     

Thermo‐mechanical and adhesive properties of polymeric films based on ZnAl‐hydrotalcite composites for active wound dressings

Composite films based on sodium carboxymethyl cellulose (Na‐CMC) loaded with a ZnAl(OH)₂CO₃·yH₂O hydrotalcite (ZnAl‐HTlc), were developed and characterized. The composites were mechanically more stable than the matrix alone: the noticeable enhancement of elastic modulus, creep resistance and failure properties, all proportional to the filler content, came at the expenses of a certain embrittlement. The filler tended to aggregate in the composites and the size of the aggregates increased with ZnAl‐HTlc amount. Contact angle measurements highlighted how ZnAl‐HTlc introduction in the polymeric matrix could strongly modify the wettability conditions of the films increasing their hydrophilicity. Bioadhesion tests showed that the adhesion behavior of the composites decreased as ZnAl‐HTlc amount increases, testifying the influence of the filler on the ability of the film to bind skin surface. Therefore, the developed films may find application as active wound dressings since ZnAl‐HTlc can be easily intercalated with an active pharmaceutical ingredient to be progressively released on the wound. POLYM. ENG. SCI., 59:E112–E119, 2019. © 2018 Society of Plastics Engineers     

Structural Design,Synthesis and Structure–Activity Relationships of Thiazolidinones with Enhanced Anti‐Trypanosoma cruzi Activity

Pharmacological treatment of Chagas disease is based on benznidazole, which displays poor efficacy when administered during the chronic phase of infection. Therefore, the development of new therapeutic options is needed. This study reports on the structural design and synthesis of a new class of anti‐Trypanosoma cruzi thiazolidinones ( 4 a – p ). (2‐[2‐Phenoxy‐1‐(4‐bromophenyl)ethylidene)hydrazono]‐5‐ethylthiazolidin‐4‐one ( 4 h ) and (2‐[2‐phenoxy‐1‐(4‐phenylphenyl)ethylidene)hydrazono]‐5‐ethylthiazolidin‐4‐one ( 4 l ) were the most potent compounds, resulting in reduced epimastigote proliferation and were toxic for trypomastigotes at concentrations below 10 μM , while they did not display host cell toxicity up to 200 μM . Thiazolidinone 4 h was able to reduce the in vitro parasite burden and the blood parasitemia in mice with similar potency to benznidazole. More importantly, T. cruzi infection reduction was achieved without exhibiting mouse toxicity. Regarding the molecular mechanism of action, these thiazolidinones did not inhibit cruzain activity, which is the major trypanosomal protease. However, investigating the cellular mechanism of action, thiazolidinones altered Golgi complex and endoplasmic reticulum (ER) morphology, produced atypical cytosolic vacuoles, as well as induced necrotic parasite death. This structural design employed for the new anti‐T. cruzi thiazolidinones ( 4 a – p ) led to the identification of compounds with enhanced potency and selectivity compared to first‐generation thiazolidinones. These compounds did not inhibit cruzain activity, but exhibited strong antiparasitic activity by acting as parasiticidal agents and inducing a necrotic parasite cell death.     

Thermal resistance analysis by induced transient (TRAIT) method forpower electronic devices thermal characterization. I. Fundamentals andtheory

In this paper, a careful theoretical analysis of the thermal dynamics of an electronic device and its package was carried out in order to study the problem of the equivalent thermal circuit implementation. It was found that the device temperature evolution in time is ruled by an infinite and convergent series of time constants. The knowledge of the first n terms of the time-constant spectrum obtained from the temperature transient measurements allows the complete characterization of a suitable and reliable equivalent thermal circuit structured as a Cauer low-pass network with n cells. The total thermal resistance is therefore evaluated as a sum of several contributions due to given parts of the whole system. The techniques allowing the physical identifications of these contributions are also discussed. Furthermore, the influence of plastic coverage on the device thermal behavior is taken into account. The proposed characterization method is also applied to one-dimensional (1-D) multilayered simulated structures in order to study the influence of the number of time constants used for the analysis and effects of local defects or modifications of the material thermal properties     

Two and three-dimensional pattern recognition of organized surfaces by specific antibodies

Understanding molecular recognition of supramolecules for solid substrates is essential for designing chemical sensors and molecular devices. The rules of molecular recognition are well established at the level of single molecules. However, during the transition from molecular-scale devices to macroscopic devices, issues concerning control over recognition that are well-established at the molecular level become much more complex. Hopefully, the conceptual and practical considerations reported here will clarify some of these issues. The immune system uses antibodies to identify molecular surfaces through molecular recognition. Antibodies are thus appropriate tools to study the rules of macromolecule-surface interactions, and this was done using crystal surfaces as substrates. Crystals can be formed or introduced into organisms and should be thus treated by the organism as any other intruder, by eliciting antibodies specific to their surfaces. A structure-recognizing antibody is defined here as complementary to a certain ordered supramolecular organization. It can be considered as a mold bearing in its binding site memory of the organization against which it was elicited. On the surface of a crystal composed of relatively small organic molecules, an antibody binding site would encompass an array of 10-20 molecular moieties. The antibody binding site would not detect one molecule, but rather a two- or three-dimensional molecular arrangement on the surface, similar to a macromolecular surface. The complementarity between antibody binding site and surface is supported by stereoselective supramolecular interactions to the repetitive structural motifs that are exposed at the surface. A procedure was developed in order to isolate monoclonal antibodies that specifically recognize a certain crystalline surface. The procedure was applied in particular to crystals of cholesterol monohydrate, of 1,4-dinitrobenzene, and of the tripeptide (S)leucine-(S)leucine-(S)tyrosine (LLY). A series of antibodies were selected and studied, three of which provided reliable specific antibody-antigen structural models. The three docking models show an astounding geometrical and chemical match of the antibody binding sites on the respective crystal surfaces. We also showed that antibodies are intrinsically capable of recognition at the length scale necessary for detection of chirality. Once the structural parameters determining the antibody specificity to the target surfaces are characterized, the antibodies may be conceivably used as reporters of the existence and location of target domains with similar structure in biological milieus. In this context, we developed and characterized monoclonal antibodies specific to crystalline mixed monolayers of cholesterol and ceramide, fundamental building blocks of lipid microdomains in cellular membranes. When used on cells, one antibody indeed labels cell membrane domains composed of cholesterol and ceramide. The fundamental contribution of the approach developed here may be in the antibody ability to report on the structural organization of paracrystalline domains that cannot be determined by other means. Alternatively, structure-recognizing antibodies may be conceivably used to carry information or build connections to specific targets, which may offer interesting developments in medicine or electronics.