Predictive models for dry weight estimation of above and below ground biomass components of Populus deltoides in India: Development and comparative diagnosis

This article concentrates on development of statistical models for prediction of biomass components (above and below ground) of standing trees of Populus deltoides. Twenty seven trees (three each from age one to nine years) were destructively harvested, separated, sorted, sub-sampled, dried to constant weight at 60 °C and weighted for biomass components (leaf, twig, branch, bole, stump root, lateral root, fine root). Harvesting in a similar manner, was continued annually up to nine years of tree age and thus in all 27 sampled trees were available for analysis and fitting of models. Diameter at breast height (dbh) alone was a very good predictor of dry weight and accordingly the height was not included in the model. Various functions viz (linear, allometric, logistic, gompertz and chapman-richards), were attempted for dry weight estimation. The linear model, though easiest to fit, suffered from the ‘negative estimation problem’, specifically for the lower range of explanatory variate. Of the remaining non-linear models, the allometric model outperformed the others on the basis of validation criterions. The value of R² ranged from 0.95 to 0.99, for the allometric models fitted on various biomass components. The proposed models can be used for prediction of component wise dry biomass of P. deltoides for a wide range of dbh values (1-50 cm) at one end and can also help farmers in the choice of economical harvest rather than the traditional physical rotation. In addition, they can be used in carbon sequestration studies, which needs complete biomass estimation.     

Development and Characterization of Self-Microemulsifying Drug Delivery System of Tacrolimus for Intravenous Administration

Tacrolimus (FK 506), a poorly soluble immunosuppressant is currently formulated in nonaqueous vehicle containing hydrogenated castor oil derivative for intravenous administration. Hydrogenated castor oil derivatives are associated with acute anaphylactic reactions. This proposes to overcome the problems of poor aqueous solubility of the drug and the toxicity associated with currently used excipients by the development of a new parenterally acceptable formulation using self-microemulsifying drug delivery system (SMEDDS). Solubility of FK 506 in various oils, surfactants, and cosurfactants was determined to identify SMEDDS components. Phase diagrams were constructed at different ratios of surfactants: cosurfactant (K_m) to determine microemulsion existence area. Influence of oily phase content, K_m, aqueous phase composition, dilution, and incorporation of drug on mean globule size of microemulsions was studied. SMEDDSs were developed using ethyl oleate as oily phase and Solutol HS 15 as surfactant. Glycofurol was used successfully as a cosurfactant. Developed SMEDDS could solubilize 0.8% (wt/wt) FK 506 and on addition to aqueous phase could form spontaneous microemulsion with mean globule size < 30 nm. The resulting microemulsion was iso-osmotic, did not show any phase separation or drug precipitation even after 24 h, and exhibited negligible hemolytic potential to red blood cells.     

Inhibition of HIV-1 by a peptide ligand of the genomic RNA packaging signal Psi

The interaction of the nucleocapsid NCp7 of the human immunodeficiency virus type 1 (HIV-1) Gag polyprotein with the RNA packaging signal Psi ensures specific encapsidation of the dimeric full length viral genome into nascent virus particles. Being an essential step in the HIV-1 replication cycle, specific genome encapsidation represents a promising target for therapeutic intervention. We previously selected peptides binding to HIV-1 Psi-RNA or stem loops (SL) thereof by phage display. Herein, we describe synthesis of peptide variants of the consensus HWWPWW motif on membrane supports to optimize Psi-RNA binding. The optimized peptide, psi-pepB, was characterized in detail with respect to its conformation and binding properties for the SL3 of the Psi packaging signal by NMR and tryptophan fluorescence quenching. Functional analysis revealed that psi-pepB caused a strong reduction of virus release by infected cells as monitored by reduced transduction efficiencies, capsid p24 antigen levels, and electron microscopy. Thus, this peptide shows antiviral activity and could serve as a lead compound to develop new drugs targeting HIV-1.     

Transient thermal behaviour of a cylindrical wood particle during devolatilization in a bubbling fluidized bed

This work proposes a transient heat transfer model to predict the thermal behaviour of wood in a heated bed of sand fluidized with nitrogen. The 2-D model in cylindrical coordinates considers wood anisotropy, variable fuel properties, fuel particle shrinkage, and heat generation due to drying and devolatilization. The influence of initial fuel moisture content, thermal diffusivity, particle geometry, shrinkage, external heat transfer coefficient, chemical reaction kinetics and heats of reaction on temperature rise is presented. The cylindrical wood particles chosen for the study have length (l) = 20 mm, diameter (d) = 4 mm and l = 50 mm and d = 10 mm, both having an aspect ratio (l/d) of 5. The bed temperature is 1123 K. The model prediction is validated using measurements obtained from literature. The temperature rise in the wood particle is found to be sensitive to changes in the moisture content and thermal diffusivity and heat of reaction (in larger particles) while it is less sensitive to the external heat transfer coefficient and chemical kinetics. Also shrinkage is found to have a compensating effect and it does not have any significant influence on the temperature rise. Beyond an aspect ratio of three, the wood particle behaves as a 1-D cylinder.     

Yield and yield components of cowpea (<Emphasis Type="Italic">Vigna unguiculata</Emphasis> (L.) Walp.) as influenced by Sokoto phosphate rock and placement methods in the semi-arid zone of Nigeria

Phosphate rock with proper management could be a sustainable source of phosphorus for increased cowpea production on the Entisols of Sokoto Semi-arid zone. Therefore, field experiments were conducted in 2004 and 2005 rainy seasons to determine the influence of Sokoto phosphate rock (SPR) and placement methods on the yield of cowpea varieties. Treatments consisted of factorial combination of two varieties (Ba’adare and IAR48), three levels of SPR (25, 50 and 75 kg SPR ha⁻¹) along with a control (0 kg SPR ha⁻¹) and three placement methods (plough sole, broadcast and side-band) laid out in a randomized complete block design replicated 3 times. Results of phosphate rock and placement methods are presented in this paper. The study indicated significant (P < 0.01) response to applied SPR compared to control (1074 kg grain ha⁻¹) in most parameters studied. Application of 25 kg SPR ha⁻¹ significantly (P < 0.05) influenced higher pod yield and number of pods plant⁻¹ only in 2004 trial. But, shelling percentage, grain yield, stover yield, 1000-grain weight, harvest index (HI) and number of seeds pods⁻¹ were not influenced by SPR levels. Significantly (P < 0.05) higher pod yield in 2004, grain yield, 1000-grain weight and number of pods per plant in 2004 and 2005, HI, shelling percentage and number of seeds pod⁻¹ in 2005, were observed in plough-sole than broadcast and band-side methods of fertilizer placement. Therefore, from this study, it was concluded that SPR could be directly used as a source of P to sustain cowpea production (1527 kg grain ha⁻¹ with 25 kg SPR compared to 1074 kg ha⁻¹with 0 kg SPR). Application of 25 kg SPR ha⁻¹ (3.74 kg P ha⁻¹) using plough-sole method of fertilizer placement was most efficient under Sokoto semi-arid condition.     

A novel nano-configuration for thermoelectrics: helicity induced thermal conductivity reduction in nanowires

In this article, we propose a novel helical nano-configuration towards the designing of high ZT thermoelectric materials. Non-equilibrium molecular dynamics (NEMD) simulations for 'model' bi-component nanowires indicate that a significant reduction in thermal conductivity, similar to that of flat superlattice nanostructures, can be achieved using a helical geometric configuration. The reduction is attributed to a plethora of transmissive and reflective phonon scattering events resulting from the steady alteration of phonon propagating direction that emerges from the continuous rotation of the helical interface. We also show that increasing the relative mass ratio of the two components lowers the phonon energy transmission at the interface due to differences in vibrational frequency spectra, thereby relatively 'easing' the phonon energy propagation along the helical pathway. While the proposed mechanisms result in a reduced lattice thermal conductivity, the continuous nature of the bi-component nanowire would not be expected to significantly reduce its electrical counterpart, as often occurs in superlattice/alloy nanostructures. Hence, we postulate that the helical configuration of atomic arrangement provides an attractive and general framework for improved thermoelectric material assemblies independent of the specific chemical composition.     

Kinetics of thermal destruction of Salmonella in ground chicken containing trans-cinnamaldehyde and carvacrol

We investigated the heat resistance of an eight-strain cocktail of Salmonella serovars in chicken supplemented with trans cinnamaldehyde (0 to 1.0%, wt/wt) and carvacrol (0 to 1.0%, wt/wt). Inoculated meat was packaged in bags that were completely immersed in a circulating water bath and held at 55 to 71°C for predetermined lengths of time. The recovery medium was tryptic soy agar supplemented with 0.6% yeast extract and 1% sodium pyruvate. D-values in chicken, determined by linear regression, were 17.45, 2.89, 0.75, and 0.29 min at 55, 60, 65, and 71°C, respectively (z = 9.02°C). Using a survival model for nonlinear survival curves, D-values in chicken ranged from 13.52 min (D(1), major population) and 51.99 min (D(2), heat-resistant subpopulation) at 55°C to 0.15 min (D(1)) and 1.49 min (D(2)) at 71°C. When the Salmonella cocktail was in chicken supplemented with 0.1 to 1.0% trans-cinnamaldehyde or carvacrol, D-values calculated by both approaches were consistently less at all temperatures. This observation suggests that the addition of natural antimicrobials to chicken renders Salmonella serovars more sensitive to the lethal effect of heat. Thermal death times from this study will be beneficial to the food industry in designing hazard analysis and critical control point plans to effectively eliminate Salmonella contamination in chicken products used in this study.     

Anomalous electrical transport properties of PVA–Ag composite films below room temperature

The direct current (dc) and alternate current (ac) electrical transport property of polyvinyl alcohol–silver (PVA–Ag) composites has been investigated within a temperature range of 77 ≤ T ≤ 300 K and in the frequency range of 20 Hz to 1 MHz in the presence as well as in the absence of a transverse magnetic field up to 1 T. The dc conductivity follows variable range hopping model. The magnetoconductivity of the samples undergoes a change from negative to positive values with the incorporation of Ag in PVA matrix, which can be interpreted by the dominancy of the forward interference effect prevailing over the wave function shrinkage effect. The ac conductivity follows a power law of frequency, whereas the temperature dependence of frequency exponent “s” can be explained by correlated barrier hopping model. The dielectric behavior of the samples has been governed by the grain and interfacial grain boundary resistance and capacitance. Two activation behaviors are observed from the analysis of grain and interfacial grain boundary contributions. POLYM. COMPOS., 33:1941–1950, 2012. © 2012 Society of Plastics Engineers     

Applications of ozone, bacteriocins and irradiation in food processing: a review

An article is presented describing the background information on the use of ozone, bacteriocins and irradiation for destroying pathogens in food products. Their effectiveness on some pathogens of importance in food processing systems and issues of concern are highlighted. It could be concluded that although each one has the potential for use as an alternative preservation technology in specific food processing applications, no single method, except irradiation, is likely to be effective against all food spoilage and food poisoning microorganisms in all food matrices. However, the synergistic effect of one of these methods and other 'hurdles' or modes of food preservations could be used to ensure the microbial safety and prevention of the development of undesirable sensory and chemical changes in some food products. Bacteriocins may contribute an additional barrier in the 'hurdle concept' of food safety.     

Shoe-last design exploration and customization

The shoe industry is a very competitive industry and in order to capture the market, customized shoes are desired nowadays to satisfy consumers’ needs on style, fit and comfort. Companies need to either develop a system for quick design changes, creation of huge virtual design variations and in some cases adoption of mass-customization principles to reduce cost. Shoe-last is the “heart” of shoe making since it mainly determines the shoe shape, fashion, fit and comfort qualities. This study proposed a system to enable shoe-last design changes, exploration and eventually enable mass-customization. The system enables continuous change of styling and fashion to reflect personal taste without the need for physical design. Design exploration involves representation of styling curves using parametric curves. Modification of the styling curves, by changing the parameter values, can be used to explore different designs. This is useful to create slight variations of shoe-last. Since the designs are parameterized, design can be scaled on individual shape and size to create customized shoe-last. Results of the study can be used to create a system for shoe-last design exploration and mass-customization system for individual designs in a cost effective manner.