Evaluation of the validity of the scalar approximation in optical wave propagation using a systems approach and an accurate digital electromagnetic model

The cause and amount of error arising from the use of the scalar approximation in monochromatic optical wave propagation are discussed using a signals and systems formulation. Based on Gauss’s Law, the longitudinal component of an electric field is computed from the transverse components by passing the latter through a two input single output linear shift-invariant system. The system is analytically characterized both in the space and frequency domains. For propagating waves, the large response for the frequencies near the limiting wave number indicates the small angle requirement for the validity of the scalar approximation. Also, a discrete simulator is developed to compute the longitudinal component from the transverse components for monochromatic propagating electric fields. The simulator output helps to evaluate the validity of the scalar approximation when the system output cannot be analytically calculated.     

Platelet‐to‐lymphocyte ratio better predicts inflammation than neutrophil‐to‐lymphocyte ratio in end‐stage renal disease patients

Neutrophil‐to‐lymphocyte ratio (NLR) was introduced as a potential marker to determine inflammation in end‐stage renal disease (ESRD) patients. Recently, platelet‐to‐lymphocyte ratio (PLR) and NLR were found to positively correlated with inflammatory markers including tumor necrosis factor‐α (TNF‐α) and interleukin (IL)‐6 in cardiac and noncardiac patients. Data regarding PLR and its association with inflammation are lacking in hemodialysis (HD) and peritoneal dialysis (PD) patients. Hence, we aimed to determine the relationship between PLR, NLR, and inflammation in ESRD patients. This was a cross‐sectional study involving 62 ESRD patients (29 females, 33 males; mean age, 49.6 ± 14.6 years) receiving PD or HD for ≥6 months in the Dialysis Unit of Necmettin Erbakan University. PLR, NLR, C‐reactive protein, TNF‐α, IL‐6 levels were measured. PLR, NLR, serum high sensitive C‐reactive protein, IL‐6, and TNF‐α levels were significantly higher in PD patients when compared with HD patients. ESRD patients with PLR ≥ 140 had significantly higher NLR, IL‐6, and TNF‐α levels when compared to patients with PLR < 139. In the bivariate correlation analysis, PLR was positively correlated with NLR, IL‐6, and TNF‐α in this population. When we compared the association of PLR and NLR with IL‐6 (r = 0.371, P = 0.003 vs. r = 0.263, P = 0.04, respectively) and TNF‐α (r = 0.334, P = 0.008 vs. r = 0.273, P = 0.032, respectively), PLR was found to be superior to NLR in terms of inflammation in ESRD patients. Simple calculation of PLR can predict inflammation better than NLR in ESRD patients.     

Extraction of Bioactive Compounds from Milled Grape Canes (Vitis vinifera) Using a Pressurized Low-Polarity Water Extractor

Trans-resveratrol and trans-ε-viniferin were extracted from milled grape canes using pressurized low-polarity water. The effects of temperature were significant for both compounds (p ≤ 0.05): extraction at 160 °C resulted in a 40% loss of trans-resveratrol compared to 95 °C while reduction of trans-ε-viniferin at both temperatures remained at 30%. Increasing ethanol concentration from 0% to 25% increased the extraction of total phenolics and trans-ε-viniferin by 44% and 489%, respectively. Solvent flow rate also influenced trans-ε-viniferin extraction. Antioxidant activity showed a strong correlation with total phenolic content of the extracts, and the two target phenolic compounds. Except for the modifier concentration, the extraction parameters studied were not statistically significant with respect to the antioxidant activity of extracts (p > 0.05). Effective diffusivities of trans-resveratrol multiplied from 3.3 × 10⁻¹¹ to 10.4 × 10⁻¹¹ m²/s by three times with increasing temperature. The modified Gompertz equation satisfactorily explained the extraction of the stilbenes investigated.     

Microstructure,Mechanical, and Scratch Resistance Properties of TiAlCrNbN-Graded Composite Coating Deposited on AISI H13 Steel Substrate with Pulsed DC Closed Field Unbalanced Magnetron Sputtering Method

Structure and adhesion properties of TiAlCrNbN coatings were investigated. These coatings were deposited onto AISI H13 steel substrate using pulsed dc closed field unbalanced magnetron sputtering at different deposition parameters including duty cycle, bias voltage, and working pressure. The coatings have been characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The TiAlCrNbN-graded composite coatings have a dense and columnar structure. The X-ray diffraction patterns of coatings exhibited predominantly c-TiAlCrN, h-NbN, and h-TiAlN reflections. Scratch resistance test showed that the highest adhesion strength was attained as 68 N at 2.5 μs duty time, 100 V bias voltages, and 3 × 10^?3 Torr deposition parameters. The lowest adhesion strength was obtained as 55 N at 0.5 μs duty time, 50V bias voltage, and 2 × 10^?3 Torr deposition parameters.     

Advances in empirically based assessment: Revised cross-informant syndromes and new DSM-oriented scales for the CBCL, YSR, and TRF: Comment on Lengua, Sadowski, Friedrich, and Fisher (2001).

L. Lengua et al. (2001) (see record 2001-18163-010) proposed scoring the Child Behavior Checklist (CBCL; T. Achenbach, (1991 b) on dimensions that "correspond to current conceptualizations of child symptomatology," (p. 695) embodied in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV; 4th ed., American Psychiatric Association, 1994). They concluded that their "results support the use of the new dimensions." Yet, their regressions and diagnostic efficiency statistics showed that DSM diagnoses were predicted less well by their dimensions than by CBCL syndromes that reflect actual patterns of problems. Not only these findings, but also the high correlations of their dimensions with CBCL syndromes and the lack of norms and validated clinical cutoffs for their dimensions, argue against use of their dimensions. To advance assessment and taxonomy, new national samples have been used to construct DSM-oriented scales and to revise cross-informant syndromes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optimization of microwave baking of model layer cakes

 Response surface methodology was used to optimize the formulation of microwave-baked cakes. The independent variables were water content, emulsifier content baking time, oven power, shortening content and starch type. The quality factors evaluated were specific gravity of batter and volume index, uniformity index and tenderness of the crumb. Constraints for quality factors were obtained by conventional baking of American Association of Cereal Chemists high-ratio cake formulation. Multiple contour plots showed the optimum region for various water and shortening combinations at different emulsifier, time and power levels. Cakes formulated with wheat starch, containing 0.3% polysorbate 60, 133.7% water and 45.2% shortening (flour substitute basis), baked for 6 min at 100% power yielded acceptable cakes that can compete with conventionally baked cakes. Rice and corn cakes had lower quality than conventionally baked high-ratio cakes. Power was found to be the most efficient independent variable affecting all the dependent variables. Received: 26 August 1999 / Revised version: 11 October 1999     

Inhibitory effect of heavy metals on methane-producing anaerobic granular sludge

Heavy metals could potentially have a negative impact on methane-producing anaerobic granular sludge. The objective of this study was to investigate the inhibitory effect of zinc(II), chromium(VI), nickel(II), and cadmium(II) on the methane-producing activity of granular sludge sampled from the upflow anaerobic sludge blanket reactor that treats the wastewaters of a yeast factory, for a range of concentrations between 0 and 128 mg L(-1). The modified Gompertz, Logistic, and Richards equations were applied to describe the inactivation of anaerobic culture by heavy metals. According to these models, the values of methane production potential (mL) for a heavy metal concentration of 128 mg L(-1) were in the following order: Ni (44.82+/-0.67)>Cd (28.73+/-0.11)>Cr (15.52+/-1.63)>Zn (0.65+/-0.00). The IC(50) values, the metal concentrations that cause a 50% reduction in the cumulative methane production over a fixed period of exposure time (24h), for the individual heavy metals were found to be in the following order: Zn (most toxic; 7.5 mg L(-1))>Cr (27 mg L(-1))>Ni (35 mg L(-1)) approximately Cd (least toxic; 36 mg L(-1)).     

Effect of packing on void morphology in resin transfer molded E‐glass/epoxy composites

Effects of applying a packing pressure on void content, void morphology, and void spatial distribution were investigated for resin transfer molding (RTM) E‐glass/epoxy composites. Packing pressures of zero and 570 kPa were respectively applied to center‐gated composites containing 17.5% randomly oriented, E‐glass fiber preform. Radial samples of these disk‐shaped composites were utilized to evaluate voidage via microscopic image analysis. Two adjacent surfaces were cut from each molded disk in order to evaluate void presence from both through‐the‐thickness and planar views. The packed composite was found to contain almost 92% less void content than the unpacked composite. While void fractions of 2.2 and 2.6% were measured, respectively, from the through‐the‐thickness and planar surfaces of the unpacked composite, only 0.2% void content was observed in the packed composite from both surfaces. Digital images obtained from through‐the‐thickness surface showed that average void size dropped from 59.3 μm in the unpacked composite to 31.7 μm in the packed composite. A similar reduction in average void size from 66.7 to 41.1 μm was observed from the planar surfaces. Circular voids were found to experience higher removal rates at 99%, followed by cylindrical and elliptical voids at 83 and 81%, respectively; while irregular voids show slightly lower void removal rates at 67%. Void proximity to fiber bundles was also observed to affect void reduction as voids located inside fiber tows experience lower void reduction rates. Along the radial direction of the molded disks, removal of voids with different proximities to fibers seems to depend on their arrangement at the end of the filling stage. These findings are believed to ascertain packing as an effective void removal method for RTM and similar liquid composite molding processes. POLYM. COMPOS., 26:614–627, 2005. © 2005 Society of Plastics Engineers     

Social dominance mediates the association of testosterone and neurobehavioral disinhibition with risk for substance use disorder.

This investigation determined the influence of testosterone and neurobehavioral disinhibition (ND) on risk for substance use disorder (SUD). Testosterone level during puberty was hypothesized to promote social dominance associated with norm-violating behavior that, in turn, predisposes individuals to use of illicit drugs and, subsequently, SUD. Using a prospective paradigm, the authors recruited 179 boys (mean age=11.62 years, SD=0.88) and followed up when participants were ages 12-14, 16, 19, and 22. Results indicated that social dominance/norm-violating behavior (SD/NVB) at age 16 mediated the association between testosterone level (ages 12-14) and SUD (age 22). In addition, SD/NVB mediated the association between ND and SUD. These findings suggest that development of SUD is influenced by androgen-dependent and neurobehavioral processes via a social motivational style characterized by SD/NVB. (PsycINFO Database Record (c) 2010 APA, all rights reserved)