Temperature effects on the conductance, spin-valley polarization and tunneling magnetoresistance of single magnetic silicene junctions.

Magnetic silicene junctions are versatile structures with spin-valley polarization and magnetoresistive capabilities. Here, we investigate the temperature effects on the transport properties of single magnetic silicene junctions. We use the transfer matrix method and the Landauer-Büttiker formalism to calculate the transmittance, conductance, spin-valley polarization and tunneling magnetoresistance. We studied the case for T = 0 K, finding the specific parameters where the spin-valley polarization and the tunneling magnetoresistance reach optimized values. Regarding the temperature effects, we find that its impact is not the same on the different transport properties. In the case of the conductance, depending on the spin-valley configuration the resonant peaks disappear at different temperatures. The spin polarization persists at a considerable value up to T=80 K, contrary to the valley polarization which is more susceptible to the temperature effects. In addition, a stepwise spin-valley polarization can be achieved at low temperature. The tunneling magnetoresistance is attenuated considerably as the temperature rises, decreasing more than two orders of magnitude after T=20 K. These findings indicate that in order to preserve the spin-valley polarization and magnetoresistive capabilities of magnetic silicene junctions is fundamental to modulate the temperature adequately.

Enhancement of the thermoelectric properties in bilayer graphene structures induced by Fano resonances.

Fano resonances of bilayer graphene could be attractive for thermoelectric devices. The special profile presented by such resonances could significantly enhance the thermoelectric properties. In this work, we study the thermoelectric properties of bilayer graphene single and double barrier structures. The barrier structures are typically supported by a substrate and encapsulated by protecting layers, reducing considerably the phonon thermal transport. So, we will focus on the electronic contribution to the thermal transport. The charge carriers are described as massive chiral particles through an effective Dirac-like Hamiltonian. The Hybrid matrix method and the Landauer-Büttiker formalism are implemented to obtain the transmission, transport and thermoelectric properties. The temperature dependence of the Seebeck coefficient, the power factor, the figure of merit and the efficiency is analyzed for gapless single and double barriers. We find that the charge neutrality point and the system resonances shape the thermoelectric response. In the case of single barriers, the low-temperature thermoelectric response is dominated by the charge neutrality point, while the high-temperature response is determined by the Fano resonances. In the case of double barriers, Breit-Wigner resonances dominate the thermoelectric properties at low temperatures, while Fano and hybrid resonances become preponderant as the temperature rises. The values for the figure of merit are close to two for single barriers and above three for double barriers. The system resonances also allows us to optimize the output power and the efficiency at low and high temperatures. By computing the density of states, we also corroborate that the improvement of the thermoelectric properties is related to the accumulation of electron states. Our findings indicate that bilayer graphene barrier structures can be used to improve the response of thermoelectric devices.

Association between dental hygiene, gingivitis and overweight or the risk of overweight in primary teeth of 4- and 5-year-old preschoolers in México.

OBJECTIVE: To determine the association between dental hygiene, gingivitis and overweight or the risk of overweight according to body mass index (BMI). METHODS: A cross-sectional study was performed with 1527 preschoolers. The children were divided into 4 groups: (i) absence of visible plaque and normal weight; (ii) absence of visible plaque and risk of overweight or overweight; (iii) presence of visible plaque and normal weight; and (iv) presence of visible plaque and risk of overweight or overweight. The clinical parameters evaluated were as follows: body mass index, degree of urban marginalization, dental caries, the simplified oral hygiene index and gingival status. Bivariate analysis and multivariate binary logistic regression models were used to identify associations between variables. RESULTS: The highest mean of gingivitis (0.28) was observed in the groups with visible plaque with normal weight and with overweight and risk of overweight. The presence of visible plaque and risk of overweight or overweight were positively associated (P = .0001) with the mean of gingivitis (OR = 8.28, 95% CI = 3.30-19.8). The absence of visible plaque and risk of overweight or overweight (P = .0001) were also positively associated with the presence of gingivitis (OR = 2.44, 95% CI = 0.68-8.06). This is after both models were adjusted by gender and degree of marginalization. CONCLUSIONS: The professionals should develop interdisciplinary approaches to (i) propose appropriate interventions to improve oral health in overweight preschoolers; and (ii) propose interventions to decrease the overweight with the possibility of also reducing its association with gingivitis.

Fano resonances in bilayer graphene superlattices.

In this work, we address the ubiquitous phenomenon of Fano resonances in bilayer graphene. We consider that this phenomenon is as exotic as other phenomena in graphene because it can arise without an external extended states source or elaborate nano designs. However, there are not theoretical and/or experimental studies that report the impact of Fano resonances on the transport properties. Here, we carry out a systematic assessment of the contribution of the Fano resonances on the transport properties of bilayer graphene superlattices. Specifically, we find that by changing the number of periods, adjusting the barriers height as well as modifying the barriers and wells width it is possible to identify the contribution of Fano resonances on the conductance. Particularly, the coupling of Fano resonances with the intrinsic minibands of the superlattice gives rise to specific and identifiable changes in the conductance. Moreover, by reducing the angular range for the computation of the transport properties it is possible to obtain conductance curves with line-shapes quite similar to the Fano profile and the coupling profile between Fano resonance and miniband states. In fact, these conductance features could serve as unequivocal characteristic of the existence of Fano resonances in bilayer graphene.

[Breast Cancer Survival: Clinical andPathological Prognostic Factors Analysis]. / Supervivencia de pacientes con cáncer de mama. Análisis por factores pronóstico, clínicos y patológicos.

Background: Breast cancer is the leading cause of cancer death in women in Mexico, is a heterogeneous disease, and knowledge of prognostic factors are critical in making treatment decisions. Objetive: determine the overall survival (OS) and disease-free survival (DFS) at 5 years, analyzed by risk groups. Material and methods: Patients diagnosed with breast treated at the Institute of Breast Diseases FUCAM from July 2005 to December 2014 were included. Simple frequencies were used for analysis of the general characteristics, and 5- year OS and DFS were analyzed using Kaplan-Meier curves. A subset analysis of the clinical stage and comparing survival in those patients diagnosed by mammography screening program was performed. Results: 4,902 patients with breast cancer were included, general clinical and pathological features are described and 3,762 patients were included for analysis of 5-year OS and DFS. The average age at diagnosis was 53.7 years; 13.3% were <40 years, which deleteriously reflects on the supervivencia global 76 vs 84% in >40. At diagnosis predominated locally advanced stages (45%), OS and DFS at 5 years was 96.8 ± 0.6% and 93.4%±0.9 respectively for early stages, 74.6 ± 1.7% and 68.7 ± 2% for locally advanced and 35.9 ± 5.1% and 37.4 ± 10.3% for metastatic tumors. Women diagnosed in the screening program had significantly better OS and DFS compared with symptomatic patients (95 and 93% vs 79 and 77%). For biological subtypes, OS and DFS was 89 and 84% for luminal, 81 and 81% for luminal Her +, 74 and 78% for pure Her 2, and 69 and 73% for triple negative. Conclusion: Knowledge of the prognostic factors that affect survival of patients with breast cancer is essential for categorizing risk groups and to individualize treatment in order to improve life expectancy.

Pulmonary hypertension due to acute respiratory distress syndrome

Our aims were to describe the prevalence of pulmonary hypertension in patients with acute respiratory distress syndrome (ARDS), to characterize their hemodynamic cardiopulmonary profiles, and to correlate these parameters with outcome. All consecutive patients over 16 years of age who were in the intensive care unit with a diagnosis of ARDS and an in situ pulmonary artery catheter for hemodynamic monitoring were studied. Pulmonary hypertension was diagnosed when the mean pulmonary artery pressure was >25 mmHg at rest with a pulmonary artery occlusion pressure or left atrial pressure <15 mmHg. During the study period, 30 of 402 critically ill patients (7.46%) who were admitted to the ICU fulfilled the criteria for ARDS. Of the 30 patients with ARDS, 14 met the criteria for pulmonary hypertension, a prevalence of 46.6% (95% CI; 28-66%). The most common cause of ARDS was pneumonia (56.3%). The overall mortality was 36.6% and was similar in patients with and without pulmonary hypertension. Differences in patients' hemodynamic profiles were influenced by the presence of pulmonary hypertension. The levels of positive end-expiratory pressure and peak pressure were higher in patients with pulmonary hypertension, and the PaCO2 was higher in those who died. The level of airway pressure seemed to influence the onset of pulmonary hypertension. Survival was determined by the severity of organ failure at admission to the intensive care unit.

Pulmonary hypertension due to acute respiratory distress syndrome.

Our aims were to describe the prevalence of pulmonary hypertension in patients with acute respiratory distress syndrome (ARDS), to characterize their hemodynamic cardiopulmonary profiles, and to correlate these parameters with outcome. All consecutive patients over 16 years of age who were in the intensive care unit with a diagnosis of ARDS and an in situ pulmonary artery catheter for hemodynamic monitoring were studied. Pulmonary hypertension was diagnosed when the mean pulmonary artery pressure was >25 mmHg at rest with a pulmonary artery occlusion pressure or left atrial pressure <15 mmHg. During the study period, 30 of 402 critically ill patients (7.46%) who were admitted to the ICU fulfilled the criteria for ARDS. Of the 30 patients with ARDS, 14 met the criteria for pulmonary hypertension, a prevalence of 46.6% (95% CI; 28-66%). The most common cause of ARDS was pneumonia (56.3%). The overall mortality was 36.6% and was similar in patients with and without pulmonary hypertension. Differences in patients' hemodynamic profiles were influenced by the presence of pulmonary hypertension. The levels of positive end-expiratory pressure and peak pressure were higher in patients with pulmonary hypertension, and the PaCO2 was higher in those who died. The level of airway pressure seemed to influence the onset of pulmonary hypertension. Survival was determined by the severity of organ failure at admission to the intensive care unit.

Application of a modified sequential organ failure assessment score to critically ill patients.

The purpose of the present study was to explore the usefulness of the Mexican sequential organ failure assessment (MEXSOFA) score for assessing the risk of mortality for critically ill patients in the ICU. A total of 232 consecutive patients admitted to an ICU were included in the study. The MEXSOFA was calculated using the original SOFA scoring system with two modifications: the PaO2/FiO2 ratio was replaced with the SpO2/FiO2 ratio, and the evaluation of neurologic dysfunction was excluded. The ICU mortality rate was 20.2%. Patients with an initial MEXSOFA score of 9 points or less calculated during the first 24 h after admission to the ICU had a mortality rate of 14.8%, while those with an initial MEXSOFA score of 10 points or more had a mortality rate of 40%. The MEXSOFA score at 48 h was also associated with mortality: patients with a score of 9 points or less had a mortality rate of 14.1%, while those with a score of 10 points or more had a mortality rate of 50%. In a multivariate analysis, only the MEXSOFA score at 48 h was an independent predictor for in-ICU death with an OR = 1.35 (95%CI = 1.14-1.59, P < 0.001). The SOFA and MEXSOFA scores calculated 24 h after admission to the ICU demonstrated a good level of discrimination for predicting the in-ICU mortality risk in critically ill patients. The MEXSOFA score at 48 h was an independent predictor of death; with each 1-point increase, the odds of death increased by 35%.

Application of a modified sequential organ failure assessment score to critically ill patients

The purpose of the present study was to explore the usefulness of the Mexican sequential organ failure assessment (MEXSOFA) score for assessing the risk of mortality for critically ill patients in the ICU. A total of 232 consecutive patients admitted to an ICU were included in the study. The MEXSOFA was calculated using the original SOFA scoring system with two modifications: the PaO2/FiO2 ratio was replaced with the SpO2/FiO2 ratio, and the evaluation of neurologic dysfunction was excluded. The ICU mortality rate was 20.2%. Patients with an initial MEXSOFA score of 9 points or less calculated during the first 24 h after admission to the ICU had a mortality rate of 14.8%, while those with an initial MEXSOFA score of 10 points or more had a mortality rate of 40%. The MEXSOFA score at 48 h was also associated with mortality: patients with a score of 9 points or less had a mortality rate of 14.1%, while those with a score of 10 points or more had a mortality rate of 50%. In a multivariate analysis, only the MEXSOFA score at 48 h was an independent predictor for in-ICU death with an OR = 1.35 (95%CI = 1.14-1.59, P < 0.001). The SOFA and MEXSOFA scores calculated 24 h after admission to the ICU demonstrated a good level of discrimination for predicting the in-ICU mortality risk in critically ill patients. The MEXSOFA score at 48 h was an independent predictor of death; with each 1-point increase, the odds of death increased by 35%.

Intercontinental spread from Israel to Colombia of a KPC-3-producing Klebsiella pneumoniae strain.

In 2008, an increase in the prevalence of carbapenem-resistant Klebsiella pneumoniae was noted in a 286-bed tertiary case hospital in Colombia, where 84 patients (32 infected and 52 colonized) had positive cultures. The identified index patient came from Israel for a liver transplantation. High level carbapenem resistance was observed. Polymyxin B and tigecycline were the only two antibiotics that remained active. PCR-restriction fragment length polymorphism analysis and sequencing revealed blaKPC-3 in the major clone, which was indistinguishable from the K. pneumoniae carbapenemase-3-producing clone described previously in Israel. This exemplifies the threat posed by the global spread of K. pneumoniae carbapenemase-producing pathogens.

Trastornos de coagulación en trauma craneoencefálico / Coagulation disorders in cranioencephalic trauma

La comprensión del proceso de la coagulación ha progresado durante la última década, evolucionando a partir del concepto según el cual la producción del coágulo se iniciaba por acción de las plaquetas y la activación de uno de los dos sistemas separados, la vía extrínseca y la vía intrínseca, al concepto actual que hace énfasis sobre la vía común y un sistema proteolítico que da lugar a la degradación de los coágulos formados y a la prevención de la formación indeseada de coágulos. La alteración de este equilibrio cobra especial importancia en los pacientes con trauma craneoencefálico, en quienes -a la luz de los conocimientos actuales- se pueden presentar trastornos de la coagulación que van desde lesiones procoagulantes, en un extremo, hasta lesiones anticoagulantes, en el otro extremo. La meta de los autores es brindar a los clínicos de una guía de evaluación inicial, de seguimiento y, de las posibilidades terapéuticas disponibles en el momento.

The understanding of the coagulation process has progressed during last decade evolving from the concept according to which the production of the clot begins by means of the action of platelets and the activation of one of two separated systems, the extrinsic route and the intrinsic route, to the present concept that makes emphasis on the common route and a proteolytic system that give rise to the degradation of formed clots and to the undesired prevention of the formation of the clot. The alteration of this balance receives special importance in the patients with brain trauma in those who to the light of the present knowledge may present upheavals of the coagulation which can go from procoagulating injuries in one end to anticoagulating injuries in the other. The goal of the authors is to provide a clinical guide with initial evaluation, pursuit and therapeutic possibiliti.es available at the moment.

Mandibular gland chemistry of four Caribbean species of Camponotus (Hymenoptera: Formicidae).

The volatile components of whole-body extracts of males, females and workers were analyzed in four species of Neotropical ants in the formicine genus, Camponotus. The species, C. kaura, C. sexguttatus, C. ramulorum and C. planatus, represent three different subgenera. Volatile mandibular gland components were found only in male extracts in three of the species. In C. ramulorum, volatile components were found in male and female reproductives and workers. 3,4-Dihydro-3,5-dihydroxy-6-methylpyran-4-one and octanic acid were found in different sets of three of the species. Methyl 6-methyl salicylate was found in two species and the isocoumarin, mellein, was found in a third species. The significance of the mandibular gland secretion for formicid systematics is discussed.

Hyperplastic changes and receptor status in the breast tissue of bodybuilders under anabolic-androgenic steroid stimulation.

Anabolic androgenic steroids (AAS) are misused by athletes to improve their physical performance. AAS with similar groups and configuration indicate that testosterone is the base of this ability to stimulate anabolic activity. The effect of these compounds on the breast tissue of males that consume them is a confirmation of its metabolic pathway. To confirm its hormonal effects, the status of estradiol and progesterone receptors (ER, PgR) status was determined in cytoplasmic and nuclear fractions (HRc, HRn) of 8 premalignant breast tissues from 8 bodybuilders (aged 21 to 45 years) under AAS stimulation. The control group included 5 males with benign disorders of the breast, but not due to AAS administration. The concentrations of ERc and ERn were significantly higher (p < .05) in males under AAS stimulation than in males without these. The concentrations of PgRc and PgRn do not differ between these two groups (p > .05) The benign breast disease is remarkably similar in female and male patients, suggesting a common origin. In the same way, the measurement of both HRc and HRn is necessary to accurately report receptor concentration.

Morphological and cytochemical characterization of female Anopheles albimanus (Diptera: Culicidae) hemocytes.

Hemocytes of 2- to 3-d-old female Anopheles albimanus Wiedemann are described by morphology, cytochemistry, and functional criteria. Supplemented Grace's insect medium in a modified Foley's perfusion method was used to obtain hemolymph from An. albimanus. Morphological analysis indicated 3 types of hemocytes were present, prohemocytes, plasmatocytes, and granular cells. Prohemocytes were small round cells with a high nuclear/cytoplasmic ratio. Plasmatocytes were the most abundant cell types in the hemolymph, and appeared as small to large and spindle-shaped cells with round or elongate nucleus, variable number of vacuoles, small granules, and pseudopodia. Granular cells were small to large and round with a large number of cytoplasmic granules, vacuoles, and numerous filopodia. Ultrastructurally, prohemocytes were undifferentiated with abundant free ribosomes and with few small electron-dense granules. Plasmatocytes were rich in mitochondria, rough endoplasmic reticulum, free ribosomes, small electron-dense granules, numerous peripheral vacuoles and with an important organelle polarization. Granular cells contained numerous large electron-dense granular inclusions and vacuoles. Cytochemical studies showed that plasmatocytes and granular cells have cationic bactericidal proteins. Only granular cells showed phenoloxidase and probably lysosomal activities. In vitro functional studies demonstrated that both plasmatocytes and granular cells were able to attach to glass slides, and only plasmatocyte had phagocytic activity and motility. These results characterize the hemocytes of An. albimanus and suggest that plasmatocytes and granular cells may have a role in defense responses to foreign organisms.

Investigation of the temporal humoral immune response in a murine model of actinomycetoma.

The murine model of actinomycetoma offers the potential of studying many unknown aspects of this infection. In this work, the model was used to investigate the temporal humoral immune response to actinomycetoma agents. Groups of 7- to 9-week-old female BALB/c mice were inoculated in one of the hind footpads with one of four different Nocardia strains. To mimic the constant exposure of infected humans to the virulent soil inhabiting agents, a second injection consisting of live nocardiae in incomplete Freund's adjuvant was administered five months after the first one. Murine serum samples were collected throughout the study and their IgM and IgM titers were determined by ELISA and the Western blot assay. The results obtained indicate that the ELISA titers increased as the infection progressed and this correlated with a greater number of antigen bands being recognized in the blots. Overall, however, the ELISA titers were lower for the N. brasiliensis infected mice than those of the N. asteroides ones. This observation may be indicative of an immunosuppressive state and is worthy of further investigation.

Investigation of the temporal humoral immune response in a murine model of actinomycetoma

The murine model of actinomycetoma offers the potential of studying many unknown aspects of this infection. In this work, the model was used to investigate the temporal humoral immune response to actinomycetoma agents. Groups of 7- to 9-week-old female BALB/c mice were inoculated in one of the hind footpads with one of four different Nocardia strains. To mimic the constant exposure of infected humans to the virulent soil inhabiting agents, a second injection consisting of live nocardiae in incomplete Freund's adjuvant was administered five months after the first one. Murine serum samples were collected throughout the study and their IgM and IgM titers were determined by ELISA and the Western blot assay. The results obtained indicate that the ELISA titers increased as the infection progressed and this correlated with a greater number of antigen bands being recognized in the blots. Overall, however, the ELISA titers were lower for the N. brasiliensis infected mice than those of the N. asteroides ones. This observation may be indicative of an immunosuppressive state and is worthy of further investigation

Chemistry of venom alkaloids in someSolenopsis (Diplorhoptrum) species from Puerto Rico.

A number of 15-carbon alkaloids have been identified in venom extracts of four Puerto Rican species of ants in the genusSolenopsis (Diplorhoptrum). Workers of a species from El Verde produced thecis andtrans isomers of 2-methyl-6-nonylpiperidine with the latter isomer predominating. The same compounds were identified in queens of a species from Río Grande, but in this species no alkaloids were detected in worker extracts. Workers of aDiplorhoptrum species collected on Mona Island produced primarily atrans-2-methyl-6-(Z-4-nonenyl)piperidine,3, with smaller amounts of thecis isomer, whereas the major compound found in the queens of the same species on Mona Island was (5Z,9Z)-3-hexyl-5-methylindolizidine, identical with the alkaloid produced by queens of a species collected on Cabo Rojo. Surprisingly, workers of the Cabo Rojo species produced (5Z,9Z)- and (5E,9E)-3-butyl-5-propylindolizidine (4 and5, respectively) reported earlier as the 223AB indolizidines from skins of dendrobatid frogs. The possible significance of the qualitative and quantitative differences in the venom alkaloids synthesized by queens and workers is discussed as is the possibility that ants containing such alkaloids may serve as a dietary source for the skin alkaloids used by certain frogs in chemical defense.