Silicon Nanowire Field Effect Transistor Sensors with Minimal Sensor-to-Sensor Variations and Enhanced Sensing Characteristics.

Silicon nanowire field effect transistor (FET) sensors have demonstrated their ability for rapid and label-free detection of proteins, nucleotide sequences, and viruses at ultralow concentrations with the potential to be a transformative diagnostic technology. Their nanoscale size gives them their ultralow detection ability but also makes their fabrication challenging with large sensor-to-sensor variations, thus limiting their commercial applications. In this work, a combined approach of nanofabrication, device simulation, materials, and electrical characterization is applied toward identifying and improving fabrication steps that induce sensor-to-sensor variations. An enhanced complementary metal-oxide-semiconductor-compatible process for fabricating silicon nanowire FET sensors on 8 in. silicon-on-insulator wafers is demonstrated. The fabricated nanowire (30 nm width) FETs with solution gates have a Nernst limit subthreshold swing (SS) of 60 ± 1 mV/decade with ∼1.7% variations, whereas literature values for SS are ≥80 mV/decade with larger (>10 times) variations. Also, their threshold voltage variations are significantly (∼3 times) reduced, compared to literature values. Furthermore, these improved FETs have significantly reduced drain current hysteresis (∼0.6 mV) and enhanced on-current to off-current ratios (∼106). These improvements resulted in nanowire FET sensors with the lowest (∼3%) reported sensor-to-sensor variations, compared to literature studies. Also, these improved nanowire sensors have the highest reported sensitivity and enhanced signal-to-noise ratio with the lowest reported defect density of 2.1 × 1018 eV-1 cm-3, in comparison to literature data. In summary, this work brings the nanowire sensor technology a step closer to commercial products for early diagnosis and monitoring of diseases.

Stages of Change for Mammography Among Mexican Women and a Decisional Balance Comparison Across Countries.

An analysis of the adoption of secondary preventive behaviors is significant in regions with disparities in mammography use and breast cancer survival. Therefore, we determined the cognitive factors and the degree to which they differentiate stages of change in mammography among Mexican women. We also compared the decisional balance performance at Mexico, Switzerland, South Korea, and the USA. A cross-sectional study was designed for women in the stages of precontemplation (n = 240), contemplation (n = 243), action (n = 205), maintenance (n = 311), and relapse (n = 348). We only considered those ≥40 years with no cancer history. We measured the pros, cons, and self-efficacy, among other components. The decisional balance was estimated, and the result was transformed into T-scores. Odds ratios (OR) and 95% confidence intervals (CI) were estimated with multinomial logistic regression using precontemplation as the reference group. The decisional balance distinguished stages partially: in contemplation, the OR was 1.26 (95%CI 1.08, 1.47) and in maintenance, 1.34 (95%CI 1.13, 1.59); in action and relapse, the statistical significance was marginal (p < 0.10). The decisional balance T-score performance registered variations among countries. Additionally, the effect of self-efficacy progressively ascended from contemplation to action and maintenance (OR = 1.29 [95%CI 1.05, 1.58], 1.53 [95%CI 1.20, 1.96], and 2.48 [95%CI 1.82, 3.39], respectively). Furthermore, risk perception and severity did not have an effect on stages of change among Mexican women. Recognition of what provokes action in a population is a key factor in the efficacy of screening programs. Variations among countries highlight the necessity for importance of investigating cognitive determinants for mammography in specific areas.

[Myocardial infarction in young mexicans associated to metabolic syndrome]. / Infarto agudo al miocardio en jóvenes mexicanos asociado a síndrome metabólico.

BACKGROUND: Acute coronary diseases are catastrophic, especially in young patients. OBJECTIVE: To determine the risk of metabolic syndrome (MS) for premature acute myocardial infarction (AMI), combined with familial, behavioral, and nutritional factors in the northeast of Mexico. MATERIAL AND METHODS: This is a case control study of patients less than 47 years of age with no personal history of angina, AMI, or cerebrovascular disease. Cases corresponded to patients with AMI (incident and primary cases; n = 55) and controls were blood donors located at the same hospital (n = 55). Behavioral, nutritional, and cardiometabolic risk factors were measured. Multivariate logistic regression was used for estimating odds ratios (OR) and 95% confidence intervals (95% CI). RESULTS: MS increased the risk for premature AMI (95% CI: 1.73-39.5) eightfold, followed by smoking (OR: 7.76; 95% CI: 1.27-47.3), family history of AMI or sudden death (OR: 11.0; 95% CI: 2.03-60.4), and sedentary lifestyle (OR: 2.26; 95% CI: 2.52-9.80), independent of potential confounders. CONCLUSIONS: The study highlights the magnitude of the risk of MS for AMI in Mexican young adults. The phenomenon of coronary diseases among young adults needs essential attention from the health sector.

Temporal relationship of serum markers and tissue damage during acute intestinal ischemia/reperfusion.

OBJECTIVE: It is essential to identify a serological marker of injury in order to study the pathophysiology of intestinal ischemia reperfusion. In this work, we studied the evolution of several serological markers after intestinal ischemia reperfusion injury in rats. The markers of non-specific cell damage were aspartate aminotransferase, alanine aminotransaminase, and lactic dehydrogenase, the markers of inflammation were tumor necrosis factor alpha, interleukin-6, and interleukin-1 beta, and the markers of intestinal mucosal damage were intestinal fatty acid binding protein and D-lactate. We used Chiús classification to grade the histopathological damage. METHODS: We studied 35 Wistar rats divided into groups according to reperfusion time. The superior mesenteric artery was clamped for 30 minutes, and blood and biopsies were collected at 1, 3, 6, 12, 24, and 48 hours after reperfusion. We plotted the mean ± standard deviation and compared the baseline and maximum values for each marker using Student's t-test. RESULTS: The maximum values of interleukin-1 beta and lactic dehydrogenase were present before the maximal histopathological damage. The maximum tumor necrosis factor alpha and D-lactate expressions coincided with histopathological damage. Alanine aminotransaminase and aspartate aminotransferase had a maximum expression level that increased following the histopathological damage. The maximum expressions of interluken-6 and intestinal fatty acid binding protein were not significantly different from the Sham treated group. CONCLUSION: For the evaluation of injury secondary to acute intestinal ischemia reperfusion with a 30 minute ischemia period, we recommend performing histopathological grading, quantification of D-lactate, which is synthesized by intestinal bacteria and is considered an indicator of mucosal injury, and quantification of tumor necrosis factor alpha as indicators of acute inflammation three hours after reperfusion.

Temporal relationship of serum markers and tissue damage during acute intestinal ischemia/reperfusion

OBJECTIVE: It is essential to identify a serological marker of injury in order to study the pathophysiology of intestinal ischemia reperfusion. In this work, we studied the evolution of several serological markers after intestinal ischemia reperfusion injury in rats. The markers of non-specific cell damage were aspartate aminotransferase, alanine aminotransaminase, and lactic dehydrogenase, the markers of inflammation were tumor necrosis factor alpha, interleukin-6, and interleukin-1 beta, and the markers of intestinal mucosal damage were intestinal fatty acid binding protein and D-lactate. We used Chiús classification to grade the histopathological damage. METHODS: We studied 35 Wistar rats divided into groups according to reperfusion time. The superior mesenteric artery was clamped for 30 minutes, and blood and biopsies were collected at 1, 3, 6, 12, 24, and 48 hours after reperfusion. We plotted the mean ± standard deviation and compared the baseline and maximum values for each marker using Student's t-test. RESULTS: The maximum values of interleukin-1 beta and lactic dehydrogenase were present before the maximal histopathological damage. The maximum tumor necrosis factor alpha and D-lactate expressions coincided with histopathological damage. Alanine aminotransaminase and aspartate aminotransferase had a maximum expression level that increased following the histopathological damage. The maximum expressions of interluken-6 and intestinal fatty acid binding protein were not significantly different from the Sham treated group. CONCLUSION: For the evaluation of injury secondary to acute intestinal ischemia reperfusion with a 30 minute ischemia period, we recommend performing histopathological grading, quantification of D-lactate, which is synthesized by intestinal bacteria and is considered an indicator of mucosal injury, and quantification of tumor necrosis ...

Nanoscale structure, composition, and charge transport analysis of transparent conducting oxide nanowires written by focused ion beam implantation.

Realizing optically transparent functional circuitry continues to fuel scientific and technological interest in transparent conducting oxides (TCOs). However, precise means for creating transparent interconnects for device-to-device integration has remained elusive. Here we report on the chemical, microstructural, and electronic properties of transparent conducting oxide nanowires (Ga-doped In(2)O(3)) created by direct-write focused ion beam (Ga(+)) implantation within an insulating oxide substrate (In(2)O(3)). First, methodology for preparing TEM-ready samples is presented that enables detailed TEM-based analysis of individual nanowires. Differences in diffraction features between doped and undoped oxide regions, accompanied by RTA results, support a model in which oxygen vacancies and amorphization comprise the predominant doping/carrier creation mechanism. The same isolated nanowires are then subjected to chemical profiling, providing quantitative information on the lateral Ga doping dimensions, which are in good agreement with conductive AFM images. Furthermore, spatially selective nanoscale EELS spectroscopy provides additional evidence for changes in the oxygen site chemical environment in the FIB-processed/doped In(2)O(3), and for negligible changes in the surrounding non-FIB-processed/undoped oxide. The nanowires exhibit ohmic electrical behavior and with an average estimated conductivity of 1600-3600 S cm(-1), similar to macroscale Ga-doped In(2)O(3) films grown by conventional processes.

Prevention of gliotic scar formation by NeuroGel allows partial endogenous repair of transected cat spinal cord.

Spinal cords of adult cats were transected and subsequently reconnected with the biocompatible porous poly (N-[2-hydroxypropyl] methacrylamide) hydrogel, NeuroGel. Tissue repair was examined at various time points from 6-21 months post reconstructive surgery. We examined two typical phenomena, astrogliosis and scar formation, in spines reconstructed with the gel and compared them to those from transected non-reconstructed spines. Confocal examination with double immunostaining for glial fibrillary acidic protein (GFAP) and myelin basic protein (MBP) showed that the interface formed between the hydrogel and the spine stumps did prevent scar formation and only a moderate gliosis was observed. The gel implant provided an adequate environment for growth of myelinated fibers and we saw angiogenesis within the gel. Electron microscopy showed that regenerating axons were myelinated by Schwann cells rather than oligodendrocytes. Moreover, the presence of the gel implant lead to a considerable reduction in damage to distal caudal portions of the spine as assessed by the presence of more intact myelinated fibers and a reduction of myelin degradation. Neurologic assessments of hindlimb movement at various times confirmed that spinal cord reconstruction was not only structural but also functional. We conclude that NeuroGel lead to functional recovery by providing a favorable substrate for regeneration of transected spinal cord, reducing glial scar formation and allowing angiogenesis.

Consideraciones sobre aparatología ortodoncica vestibular / Vestibular orthodontic considerations

Aparato ortodóncico es cualquier mecanismo productor de fuerza y dentro de este amplio concepto hay una gran variedad de métodos capaces de llevar a buen fin el plan de tratamiento. Por su posición en boca, por el lugar que ocupa, por su característica de anclaje y por otros motivos, los aparatos pueden ser, vestibulares, linguales, fijos, movibles. Nosotros trataremos en este trabajo de hacer un estudio de algunos de aquellos que se ubican en el vestíbulo de la arcada dentaria, o sea los aparatos fijos vestibulares, recordando que es mas del arco o arco, hay que recurrir a medios de anclaje para fijarlo, para movilizar dientes o sectores óseo dentarios.