RESUMEN

INTRODUCTION: Illicit drugs abuse is associated with several clinical life-threatening consequences that are primarily mediated by oxidative damage to multiple cellular components with a subsequent cellular dysfunction and death. Primarily, this study aimed to investigate oxidative stress to protein and lipid components of circulatory platelets among chronic heroin and hashish addicts. METHODS: Platelet lysates were prepared from 20 chronic intravenously administrated heroin addicts and 20 chronic smoked hashish addicts. For comparative purposes, two control groups of 20 cigarette smokers and 20 nonsmokers were included in the study. Oxidative stress to platelet's proteins and lipids was investigated using carbonyl group contents assay and thiobarbituric acid reactive substances (TBARS) assay, respectively. RESULTS: In comparison to control groups, carbonyl group contents and TBARS concentration were significantly higher among heroin addicts but not among hashish addicts. Both of these markers were significantly correlated to the duration of addiction but not to the daily administrated dose. While in regard of the timing of the latest administrated dose (TLAD), only carbonyl group contents were significantly correlated to the TLAD. CONCLUSIONS: Considering the contribution of drug's route of administration, drug's pharmacokinetics, and kinetics of circulatory platelet, we concluded that chronic heroin addiction is associated with significant levels of oxidative stress to platelet's proteins and lipids. Due to the high proteomic contents of platelets, protein's oxidative stress is more prominent compared to lipids. Chronic hashish smoking is not associated with significant levels of oxidative stress in platelet's proteins and lipids.

Asunto(s)

RESUMEN

Neurotrophins are present in the gastrointestinal tract where they participate in the survival and growth of enteric neurons, augmentation of enteric circuits, elevation of colonic myoelectrical activity and also in different aspects of colitis. Previous studies largely focused on the role of neural and mucosal neurotrophins in gut inflammation. The expression of neurotrophins in colonic smooth muscle cells (SMCs) and the interactions of this potential source with colitis has not been studied in the gut. The expression of NGF, BDNF, NT-3 and NT-4 in SMCs from longitudinal and circular muscle layers of rat colon from normal and dextran sodium sulphate (DSS)-induced colitis rats was measured by ELISA. NGF, BDNF, NT-3 and NT-4 are differentially expressed in both longitudinal and circular SMCs, where the expressions of BDNF and NT-4 proteins were greater in SMCs from the longitudinal muscle layer than from the circular muscle layer, while NGF protein expression was greater in circular SMCs and NT-3 expression was equal in cells from both muscle layers. Induction of colitis with DSS significantly alters neurotrophins expression pattern in colonic SMCs. NGF levels upregulated in circular SMCs. BDNF level was increased in DSS-induced colitis in longitudinal SMCs. NGF, NT-3 and NT-4 levels were downregulated in longitudinal SMCs of DSS-induced colitis rats' colon. Disturbances of neurotrophins expression in SMCs resulted from colitis might account for the structural and functional changes in inflammatory bowel disease (IBD) such as loss of innervation and characteristic hypercontractility of longitudinal muscle in IBD.

Asunto(s)

RESUMEN

BACKGROUND: The sella turcica is an important anatomic and radiologic entity. The dimensions of the sella turcica vary greatly in normal individuals and are influenced by genetic and local factors. The main objective of this study is to build up a normative database of the dimensions of the sella turcica in the Jordanian population. MATERIALS AND METHODS: For this purpose 509 computed cephalograms of 252 male and 257 female healthy Jordanians aged 10-40 years were collected and divided into two adolescent and adult age-groups for both genders. Viewbox 3 software was used to determine linear dimensions and area of the sella turcica. RESULTS: Our results showed that the overall values for width, length, height, area, and aperture (interclinoid distance) were 8.72, 7.68, 6.25, 40.80, 3.92, and 8.67, 7.42, 6.38, 41.26, 3.68 mm (mm2) for males and females, respectively. Significant differences were found between adult male group on one hand and adolescent female group and adult female group on the other hand. Between age categories and within male and female groups, sella parameters were significantly different between adolescent and adult age-groups. CONCLUSIONS: Our data clearly confirm the classical notion of general trend of increase in parameters with age, irrespective of gender, with the area scoring the highest increase, and the height in females and length in males contributing most obviously to this trend. The aperture appears to decrease in females while it increases in males as adulthood is reached. This seems to reflect differential growth of the pituitary gland under neurohormonal effects.

Asunto(s)

RESUMEN

In this paper, we experimentally show an effective method of coupling light between dielectric waveguides and metal-dielectric-metal plasmonic waveguides using an air-slot waveguide that extends into both types of waveguides. Our experimental results validate the theoretical calculation results of the proposed coupler. In addition, we investigated the sensitivity of our design to different fabrication challenges that may result in changing the width and length of the targeted optimum values in our design. Numerical simulation results show that the cut-off wavelength can be shifted by either changing the width of the dielectric or slot waveguide. The shift occurs because, as the waveguide's width changes, the mode size changes and consequently the impedance mismatch between the dielectric and slot waveguide changes. We also found that changing the position of the air-slot waveguide with respect to the center of the dielectric waveguide resulted in a reduction in the coupling efficiency due to the reduction in the overlapped area between the mode supported by the slot waveguide and that of the dielectric waveguide.

RESUMEN

The human carrying angle (CA) is a measure of the lateral deflection of the forearm from the arm. The importance of this angle emerges from its functional and clinical relevance. Previous studies have correlated this angle with different parameters including age, gender, and handedness. However, no reports have focused on race-dependent variations in CA or its relation to various components of the elbow joint. This study aimed to investigate the variations in CA with respect to race and inter-epicondylar distance (IED) of the humerus. The study included 457 Jordanian and 345 Malaysian volunteers with an age range of 18-21 years. All participants were right-hand dominant with no previous medical history in their upper limbs. Both CA and IED were measured by well-trained medical practitioners according to a well-established protocol. Regardless of race, CA was greater on the dominant side and in females. Furthermore, CA was significantly greater in Malaysian males compared to Jordanian males, and significantly smaller in Malaysian females compared to their Jordanian counterparts. Finally, CA significantly decreased with increasing IED in both races. This study supports effects of gender and handedness on the CA independent of race. However, CA also varies with race, and this variation is independent of age, gender, and handedness. The evaluation also revealed an inverse relationship between CA and IED. These findings indicate that multiple factors including race and IED should be considered during the examination and management of elbow fractures and epicondylar diseases.

Asunto(s)

RESUMEN

An efficient coupler between a dielectric waveguide and a plasmonic metal-insulator-metal (MIM) waveguide is proposed, modeled, fabricated, and characterized. Based on the platform of a silicon slot waveguide, a quasi-MIM plasmonic junction is formed via e-beam lithography and lift-off process. Coupling efficiency between the silicon slot waveguide and plasmonic waveguide up to 43% is obtained after normalizing to reference waveguides at 1550 nm. This coupling scheme can be potentially used for fast optical switching and small-footprint optical modulation.

RESUMEN

In this paper, we present novel designs and analysis of ultra-compact couplers and 1 x 2 splitters based on plasmonic waveguides. Numerical simulation shows coupling efficiency up to 88% for the former one and 45% for each branch for the latter one. The proposed coupler design has the advantages of improving the alignment tolerance of the plasmonic waveguide with respect to the dielectric waveguide and broadening the spectrum response of the splitter.

RESUMEN

Recent work demonstrated light transmission through deep subwavelength slits or coupling light into waveguides with deep subwavelength dimension only in one direction. In this paper, we propose an approach to squeeze light (lambda = 1550 nm) from a dielectric waveguide into a deep subwavelength spot. Vertical confinement is achieved by efficiently coupling light from a dielectric waveguide into a 20-nm metal-dielectric-metal plasmonic waveguide. The horizontal dimension of the plasmonic waveguide is then tapered into 20 nm. Numerical simulation shows that light fed from a dielectric waveguide can be squeezed into a 21 nm-by-24 nm spot with efficiency 62%.

Asunto(s)