The platysma myocutaneous flap. Indications and caveats

Arterial hypertension has been identified as a major secondary risk factor for diabetic retinopathy. However, the mechanisms by which hypertension worsens retinopathy are unknown. Inhibition of advanced glycation product formation prevents the development of experimental diabetic retinopathy in normotensive diabetic rats. In this study the effect of hypertension on the rate of diabetic retinopathy development and the formation of arteriolar thrombosis was evaluated. We also evaluated the effect of aminoguanidine, an inhibitor of advanced glycation and product formation on retinal pathology of diabetic hypertensive rats. After 26 weeks of diabetes, hypertension accelerated the development of retinopathy despite a lower mean blood glucose level than in the non-hypertensive group (diabetic spontaneous hypertensive rats (SHR) 16.00 +/- 6.83 mmol/l; diabetic normotensive Wistar Kyoto rats (WKY) 34.9 +/- 3.64 mmol/l; p < 0.0001). Diabetic SHR had nearly twice as many acellular capillaries as diabetic WKY (SHR diabetic: 91.9 +/- 7.5 acellular capillaries per mm2 of retinal area vs WKY diabetic: 53.7 +/- 8.5 acellular capillaries per mm2 of retinal area), and a 3.8-fold increase in the number of arteriolar microthromboses (SHR diabetic 23,504 +/- 5523 microns2 vs SHR non-diabetic 6228 +/- 2707 microns2). Aminoguanidine treatment of SHR diabetic rats reduced the number of acellular capillaries by 50%, and completely prevented both arteriolar deposition of PAS-positive material and abnormal microthrombus formation. These data suggest that hypertension-induced deposition of glycated proteins in the retinal vasculature plays a central role in the acceleration of diabetic retinopathy by hypertension.     

Effective peer responses to impaired nursing practice

Subplate neurons, the first neurons of the cerebral cortex to differentiate and mature, are thought to be essential for the formation of connections between thalamus and cortex, such as the system of ocular dominance columns within layer 4 of visual cortex. To learn more about the requirement for subplate neurons in the formation of thalamocortical connections, we have sought to identify the neurotransmitters and peptides expressed by the specific class of subplate neurons that sends axonal projections into the overlying visual cortex. To label retrogradely subplate neurons, fluorescent latex microspheres were injected into primary visual cortex of postnatal day 28 ferrets, just prior to the onset of ocular dominance column formation. Subsequently, neurons were immunostained with antibodies against glutamate, glutamic acid decarboxylase (GAD-67), parvalbumin, neuropeptide Y (NPY), somatostatin (SRIF), or nitric oxide synthase (NOS). Retrograde labeling results indicate that the majority of subplate neurons projecting into the cortical plate reside in the upper half of the subplate. Combined immunostaining and microsphere labeling reveal that about half of cortically projecting subplate neurons are glutamatergic; most microsphere-labeled subplate neurons do not stain for GAD-67, parvalbumin, NPY, SRIF, or NOS. These observations suggest that subplate neurons can provide a significant glutamatergic synaptic input to the cortical plate, including the neurons of layer 4. If so, excitation from the axons of subplate neurons may be required in addition to that from lateral geniculate nucleus neurons for the activity-dependent synaptic interactions that lead to the formation of ocular dominance columns during development.     

1-[Carbon-11]-glucose radiation dosimetry and distribution in human imaging studies

1-[Carbon-11]-D-glucose ([11C]-glucose) is an important imaging agent for PET studies that have been used to study the normal brain, encephalitis, epilepsy, manic-depressive disorder, schizophrenia and brain tumors. METHODS: Dosimetry estimates were calculated in subjects undergoing imaging studies to help define the radiation risk of [11C]-glucose PET imaging. Time-dependent radioactivity concentrations in normal tissues in 33 subjects after intravenous injection of [11C]-glucose were obtained by PET imaging. Radiation absorbed doses were calculated according to the procedures of the Medical Internal Radiation Dose (MIRD) committee along with the variation in dose based on the calculated standard deviation of activity distribution seen in the individual patients. RESULTS: Total body exposure was a median of 3.0 microGy/MBq in men and 3.8 microGy/MBq in women. The effective dose equivalent was 3.8 microGy/ MBq in men and 4.8 microGy/MBq in women. The critical organs were those that typically take up the most glucose (brain, heart wall and liver). CONCLUSION: The organ doses reported here are small and comparable to those associated with other commonly performed nuclear medicine tests and indicate that potential radiation risks associated with this radiotracer are within generally accepted limits.     

Effect of fiber loading and orientation on mechanical and erosion wear behaviors of glass–epoxy composites

For a composite material, its mechanical behavior and surface damage by solid particle erosion depend on many factors. One of the most important factors is the fiber content. Similarly, these properties are also greatly affected by the fiber orientation. In this work, a series of experiments were carried out to investigate the influence of fiber loading and fiber orientation on mechanical and erosion behavior of glass fiber‐reinforced epoxy composites. The composites were fabricated with three different fiber loadings (20, 30, and 40 wt%) and at four different fiber orientations (15°, 30°, 45°, and 60°). The conclusions drawn on the basis of the experimental findings are discussed, and composite with 30° fiber orientation shows better microhardness compared with other fiber orientations irrespective of fiber loading. Similar observations are also noticed for other mechanical properties of the composites, such as tensile strength, flexural strength, interlaminar shear strength, impact strength, etc. Finally, the morphology of eroded surfaces is examined using scanning electron microscopy (SEM), and possible erosion mechanisms are identified. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Preparation,structural and thermo-mechanical properties of lithium aluminum silicate glass–ceramics

Lithium aluminum silicate glasses of composition (wt%) 12.6Li₂O–71.7SiO₂–5.1Al₂O₃–4.9K₂O–3.2B₂O₃–2.5P₂O₅ were prepared by the melt quench technique. These glasses were converted to glass–ceramics based on DTA data. X-ray diffraction (XRD) and Fourier transform infra-red spectroscopy (FTIR) were used to discern the phases evolved in the glass–ceramics. Phase morphology was studied using scanning electron microscopy (SEM). Thermal expansion coefficient (TEC) and glass transition temperature (T_g) of all samples were measured using thermo-mechanical analyzer (TMA). It was found that 3 h dwell time at crystallization temperature yielded samples with good crystallinity with a TEC of 9.461 × 10⁻⁶ °C⁻¹. Glass–ceramic-to-metal compressive seal with SS-304 was fabricated using LAS glass–ceramic. The presence of metal housing and compressive stresses at the glass–ceramic-to-metal interface reduced average grain size and changed the overall microstructure.     

Role of Flaxseed Meal Feeding for Different Durations in the Lipid Deposition and Meat Quality in Broiler Chickens

This study investigated the role of flaxseed meal (FSM), a rich terrestrial source of ω-3 fatty acids, in the alteration of the fatty acid profile and metabolism, health indices, physicochemical properties, and sensory quality of broiler chicken meat. The broiler chickens were fed 100 g FSM kg⁻¹ diet for different time periods (1, 2, 3, 4, and 5 weeks). The results revealed that 100 g FSM feeding in broiler chickens for at least 3 weeks increased (P < 0.01) the EPA, DHA, MUFA, PUFA, ω-3 PUFA, and ω-6 PUFA of broiler chicken meat with the corresponding decrease in palmitic acid, stearic acid, and SFA content. 100 g FSM feeding up to 3 weeks has increased the Δ⁹-desaturases (P < 0.05), thioesterase index (P < 0.01), and Δ⁵-desaturase + Δ⁶-desaturase activity (P < 0.01) along with an improvement in health indices (P < 0.01) of chicken meat. Similarly, a reduction in meat cholesterol and fat content of thigh meat (P < 0.01) was observed by feeding 100 g FSM for at least 3 weeks with no effect on the pH, color scores, and sensory evaluation of broiler chicken meat. The water-holding capacity (WHC) and extract release volume (ERV) decreased, whereas, drip loss of meat increased (P < 0.01) due to the feeding of 100 g FSM beyond 3 weeks. Thus, this study concluded that 100 g FSM feeding for 3 weeks in broiler chickens significantly improves the fatty acid profile, lipid metabolism, and health indices of meat, without compromising the physicochemical properties of broiler chicken meat.     

Comparative Study of Hybrid-Wavelet Artificial Intelligence Models for Monthly Groundwater Depth Forecasting in Extreme Arid Regions,Northwest China

Prediction of groundwater depth (GWD) is a critical task in water resources management. In this study, the practicability of predicting GWD for lead times of 1, 2 and 3 months for 3 observation wells in the Ejina Basin using the wavelet-artificial neural network (WA-ANN) and wavelet-support vector regression (WA-SVR) is demonstrated. Discrete wavelet transform was applied to decompose groundwater depth and meteorological inputs into approximations and detail with predictive features embedded in high frequency and low frequency. WA-ANN and WA-SVR relative of ANN and SVR were evaluated with coefficient of correlation (R), Nash-Sutcliffe efficiency (NS), mean absolute error (MAE), and root mean squared error (RMSE). Results showed that WA-ANN and WA-SVR have better performance than ANN and SVR models. WA-SVR yielded better results than WA-ANN model for 1, 2 and 3-month lead times. The study indicates that WA-SVR could be applied for groundwater forecasting under ecological water conveyance conditions.     

Film Flip and Transfer Process to Enhance Light Harvesting in Ultrathin Absorber Films on Specular Back‐Reflectors

Optical interference is used to enhance light–matter interaction and harvest broadband light in ultrathin semiconductor absorber films on specular back‐reflectors. However, the high‐temperature processing in oxygen atmosphere required for oxide absorbers often degrades metallic back‐reflectors and their specular reflectance. In order to overcome this problem, a newly developed film flip and transfer process is presented that enables high‐temperature processing without degradation of the metallic back‐reflector and without the need of passivation interlayers. The film flip and transfer process improves the performance of photoanodes for photoelectrochemical water splitting comprising ultrathin (<20 nm) hematite (α‐Fe₂O₃) films on silver–gold alloy (90 at% Ag–10 at% Au) back‐reflectors. Specular back‐reflectors are obtained with high reflectance below hematite films, which is necessary for maximizing the productive light absorption in the hematite film and minimizing nonproductive absorption in the back‐reflector. Furthermore, the film flip and transfer process opens up a new route to attach thin film stacks onto a wide range of substrates including flexible or temperature sensitive materials.