Innovative Organic MEH-PPV Heterojunction Device Made by USP and PVD.

An Al/p-Si/poly[2-methoxy-5-(2-ethylhexoxy)-p-phenylenevinylene] (MEH-PPV)/Ag organic heterojunction has been prepared using homemade ultrasonic spray pyrolysis (USP) equipment for deposition of the organic thin film and physical vapor deposition (PVD) for the metallic contacts. The organic layer produced on glass was analyzed by optical and morphological methods. The bandgap of the organic thin film was found to be ~ 2.03 eV with a thickness of around 140 nm, using ultraviolet-visible (UV-Vis) and scanning electron microscopy (SEM) characterization, respectively. The amorphous nature of the MEH-PPV polymer was confirmed by its x-ray diffraction pattern. To determine the electrical parameters, the heterojunction based on MEH-PPV was characterized by current-voltage (I-V) and capacitance-voltage (C-V) measurements in the dark at room temperature. The ideality factor and barrier height of the organic heterojunction were found to be 3.6 eV and 0.56 eV to 0.59 eV, respectively, with an average series resistance of 94.39 Ω, based on the I-V characteristics. The barrier height was also calculated based on the capacitance-voltage measurements, yielding slightly different results due to the applied frequencies of 10 kHz ( ϕ B = 0.50 ) and 1 MHz ( ϕ B = 0.74 ) , respectively.

Assessment of organ dose and image quality in head and chest CT examinations: a phantom study.

The purpose of this study is to assess dose for radiosensitive organs and image quality in head and chest computed tomography (CT) examinations. Our focus was in the brain, eye lens and lung organs using two protocols; one protocol with fixed mAs and filtered back projection (FBP) and another with tube current modulation (TCM) and sinogram affirmed iterative reconstruction (SAFIRE). Measurements were performed on a 128-slice CT scanner by placing thermoluminescent dosimeters (TLDs) in an anthropomorphic adult phantom. Results were compared to a CT-Expo software. Objective image quality was assessed in terms of signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). SPSS software was used for data analyses. Results showed that, using TCM, doses were reduced by 22.84%-25.06% for brain, by 21.82%-23.48% for eye lens and by 54%-53.22% for lung with TLD and CT-Expo respectively. The increased SNR and CNR values achieved for scans performed with TCM combined with iterative reconstruction techniques were 38.68%-58.81% and 38.91%-43.60% respectively. We conclude that, using TCM, a significant mean organ dose reduction is achieved for brain, eye lens and lung organs. Then, combined with iterative reconstruction, image quality was well maintained in terms of SNR and CNR. Thus it is highly recommended in clinical practice optimization in head and chest CT examinations.

Tissue magnetic susceptibility mapping as a marker of tau pathology in Alzheimer's disease.

Alzheimer's disease is connected to a number of other neurodegenerative conditions, known collectively as 'tauopathies', by the presence of aggregated tau protein in the brain. Neuroinflammation and oxidative stress in AD are associated with tau pathology and both the breakdown of axonal sheaths in white matter tracts and excess iron accumulation grey matter brain regions. Despite the identification of myelin and iron concentration as major sources of contrast in quantitative susceptibility maps of the brain, the sensitivity of this technique to tau pathology has yet to be explored. In this study, we perform Quantitative Susceptibility Mapping (QSM) and T2* mapping in the rTg4510, a mouse model of tauopathy, both in vivo and ex vivo. Significant correlations were observed between histological measures of myelin content and both mean regional magnetic susceptibility and T2* values. These results suggest that magnetic susceptibility is sensitive to tissue myelin concentrations across different regions of the brain. Differences in magnetic susceptibility were detected in the corpus callosum, striatum, hippocampus and thalamus of the rTg4510 mice relative to wild type controls. The concentration of neurofibrillary tangles was found to be low to intermediate in these brain regions indicating that QSM may be a useful biomarker for early stage detection of tau pathology in neurodegenerative diseases.

Long-term functional outcomes after primary surgical repair of acute and chronic patellar tendon rupture: Series of 25 patients.

OBJECTIVE: We aimed to evaluate the clinical outcomes after surgical repair of patellar tendon rupture (PTR) and compare the evolution of 2 types of rupture (acute and chronic) after the same rehabilitation protocol. METHODS: This was a prospective cohort study of patients with PTR treated between January 2006 and January 2014 in the department of trauma surgery, Ibn Rochd university hospital, Casablanca. RESULTS: We evaluated 25 patients (21 men) after a median follow-up of 75 months (range 29-120). The mean age was 34.7±8.59 years. Overall, 17 patients had acute rupture and 8 chronic rupture. Fifteen healthy volunteers (13 men) were recruited as a control group. Mean Knee Society Score (KSS) knee score was significantly higher after than before surgery (82.28±12.297 vs 20.64±7.6; P<0.0001) as was KSS function score (88.40±17.483 vs 23.40±8.98; P<0.0001). Pain measured on a visual analog scale was significantly lower after than before surgery (1.96±1.24 vs 6.60±1.26; P<0.0001). ROM and KSS knee and function scores were significantly lower on the operated than non-operated side after surgery. For both types of PTR, only knee extensor muscle strength was significantly lower on the operated than non-operated side and as compared with healthy volunteer knees. CONCLUSIONS: Surgical repair of PTR with reinforcement and an early rehabilitation program demonstrate good results after a long follow-up. However, chronic PTR may need longer or a different rehabilitation protocol of the knee-extensor apparatus.

Isokinetic imbalance of adductor-abductor hip muscles in professional soccer players with chronic adductor-related groin pain.

This study aims to compare the isokinetic profile of hip abductor and adductor muscle groups between soccer players suffering from chronic adductor-related groin pain (ARGP), soccer players without ARGP and healthy volunteers from general population. Study included 36 male professional soccer players, who were randomly selected and followed-up over two years. Of the 21 soccer players eligible to participate in the study, 9 players went on to develop chronic ARGP and 12 players did not. Ten healthy male volunteers were randomly selected from the general population as a control group. Comparison between the abductor and adductor muscle peak torques for players with and without chronic ARGP found a statistically significant difference on the dominant and non-dominant sides (p < .005), with the abductor muscle significantly stronger than the adductor muscle. In the group of healthy volunteers, the adductor muscle groups were significantly stronger than the abductor muscle groups on both dominant and non-dominant sides (p < .05). For the group of players who had developed chronic ARGP, abductor-adductor torque ratios were significantly higher on the affected side (p = .008). The adductor muscle strength was also significantly decreased on the affected side. This imbalance appears to be a risk factor for adductor-related groin injury. Therefore, restoring the correct relationship between these two agonist and antagonist hip muscles may be an important preventative measure that should be a primary concern of training and rehabilitation programmes.

Ecto 5' nucleotidase (5'NT) as a sensitive indicator of human zinc deficiency.

Ecto 5' nucleotidase (5'NT) is an integral plasma membrane enzyme located on most mammalian cells, and it is zinc dependent. We assayed 5'NT activity in the lymphocytes of two groups of subjects. The first group of six subjects had a mild state of zinc deficiency, as measured on the basis of zinc levels in lymphocytes, granulocytes, and platelets, but were otherwise healthy. They received 50 mg zinc as acetate orally for 12 weeks. The second six subjects were normal human volunteers in whom a mild state of zinc deficiency was induced experimentally by dietary techniques (4.2 to 5.6 mg daily zinc intake). For the assay of 5'NT, intact lymphocytes were incubated with 8-14C-labeled inosine monophosphate as substrate. Product and substrate were separated by thin-layer chromatography. Zinc level in cells was measured by flameless atomic absorption technique. In the first group of subjects with zinc deficiency, the decreased activity of 5'NT was corrected and the cellular zinc levels were normalized by oral zinc supplementation (p less than 0.01). In the second group of subjects, the baseline data were compared with those in early zinc depletion (4 to 8 weeks) and late depletion periods (greater than 20 weeks). A decrease in the activity of 5'NT was observed during the early zinc depletion phase. Zinc levels in lymphocytes, granulocytes, and platelets decreased significantly only during the late zinc depletion phase (p less than 0.01). Plasma zinc level did not change even during the late zinc depletion phase. Our studies show that 5'NT activity may be a sensitive and useful indicator of mild deficiency of zinc in human subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Nucleotides in lymphocytes of human subjects with zinc deficiency.

Cell-mediated immunity in human subjects is affected adversely as a result of zinc deficiency. The mechanism by which a deficiency of zinc may affect lymphocyte proliferation and functions, is not well understood at present. Nucleoside phosphorylase (NPase), a purine catabolic pathway enzyme, is zinc dependent, and a congenital deficiency of this enzyme is known to affect adversely cell-mediated immunity. This effect has been related to an accumulation of toxic nucleotides in lymphocytes as a result of NPase deficiency. Inasmuch as the effect of zinc deficiency on the activity of NPase and the levels of nucleotides in human lymphocytes has not been previously reported, we assayed these parameters in human subjects with zinc deficiency before and after zinc supplementation. A mild deficiency of zinc was diagnosed in those having decreased zinc in two out of three cell lineages (less than 42 micrograms in granulocytes, less than 48 micrograms in lymphocytes, and less than 1.70 microgram in platelets, per 10(10) cells). In comparison with five subjects with sufficient zinc, six subjects with zinc deficiency showed a decrease in the activity of NPase (p = 0.01), an increase in adenosine diphosphate (ADP) level (p = 0.008), a decreased adenosine triphosphate (ATP)-to-ADP ratio (p = 0.0001), and an increase in both guanosine triphosphate (GTP) (p = 0.02) and deoxyadenosine triphosphate (dGTP) (p = 0.04 in the lymphocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum thymulin in human zinc deficiency.

The activity of thymulin (a thymic hormone) is dependent on the presence of zinc in the molecule. We assayed serum thymulin activity in three models of mildly zinc-deficient (ZD) human subjects before and after zinc supplementation: (a) two human volunteers in whom a specific and mild zinc deficiency was induced by dietary means; (b) six mildly ZD adult sickle cell anemia (SCA) subjects; and (c) six mildly ZD adult non-SCA subjects. Their plasma zinc levels were normal and they showed no overt clinical manifestations of zinc deficiency. The diagnosis of mild zinc deficiency was based on the assay of zinc in lymphocytes, granulocytes, and platelets. Serum thymulin activity was decreased as a result of mild zinc deficiency and was corrected by in vivo and in vitro zinc supplementation, suggesting that this parameter was a sensitive indicator of zinc deficiency in humans. An increase in T101-, sIg-cells, decrease in T4+/T8+ ratio, and decreased IL 2 activity were observed in the experimental human model during the zinc depletion phase, all of which were corrected after repletion with zinc. Similar changes in lymphocyte subpopulation, correctable with zinc supplementation, were also observed in mildly ZD SCA subjects. Inasmuch as thymulin is known to induce intra- and extrathymic T cell differentiation, our studies provide a possible mechanism for the role of zinc on T cell functions.