Effect of seasonal variations and lactation times on aflatoxin M1 contamination in milk of different species from Punjab, Pakistan

During October 2009 to September 2010, aflatoxin M₁ (AFM₁) levels were analyzed by HPLC-FLD in 356 milk samples of different lactating species (buffalo, cow, goat, sheep and camel) from Punjab (Pakistan). Recoveries of AFM₁ ranged from 92 to 97% and the limit of detection (LOD) was 0.004 μg/L. For all lactating species the mean concentration of AFM₁ was significantly higher in winter season than in summer (p < 0.05). The results showed that 55, 56, 32, 58 and 27% of winter milk samples of buffalo, cow, goat, sheep and camel exceeded the EU maximum limit (0.05 μg/kg), compared with 38, 33, 21, 36 and 14% of summer milk samples, respectively. For all lactating species the mean concentration of AFM₁ was significantly higher in morning milks than in evening milks (p < 0.05). The percentage of morning milk samples exceeding the EU maximum limit was 72, 67, 69, 71 and 44% for buffalo, cow, goat, sheep and camel, while for evening milks percent non compliant rates were 39, 30, 18, 33 and 25%, respectively. The level of AFM₁ tended to be higher in animal species fed mainly on concentrate mixtures (buffalo and cow) than in other species grazing on fresh greens.     

Improved analysis of the intermodulation performance of ferroelectric thin-film and bulk-based varactors

In this paper, Fourier cosine series are proposed for representing the hard nonlinear dependence of the permittivity and conductance of a ferroelectric material on the DC bias voltage. Using these Fourier series representations closed-form expressions are obtained for the amplitudes of the fundamental and third-order intermodulation products generated when a exposing ferroelectric-based varactor to a DC bias voltage plus an equal-amplitude two-sinusoids signal. The results clearly show the strong and complicated dependence of the third-order intermodulation performance on the DC bias voltage, the temperature and the amplitude of the sinusoid. The results obtained suggest that the DC bias voltage and/or the temperature play an important role in deciding the nonlinear performance of the ferroelectric-based varactors.     

Analysis of Multi-Server Scheduling Paradigm for Service Guarantees during Network Mobility

Multi-server scheduling of traffic flows over heterogeneous wireless channels affix fresh concerns of inter-packet delay variations and associated problems of out-of-sequence reception, buffer management complexity, packet drops and re-ordering overhead. In this paper, we have presented an exclusive multi-server scheduling algorithm that is specifically tuned for mobile routers equipped with multiple wireless interfaces and has attained multiple care-of-address registrations with its home agent (HA). The proposed adaptive, Self-clocked, Multi-server (ASM) scheduling algorithm is based on predetermined transmission deadlines for each arrived packet at the mobile router. The mobile flows receive desired service levels in accordance with their negotiated service rates and are only constraint by the cumulative capacity of all active links. The major challenge lies in the handling of asymmetric channels to stitch into a unified virtual channel of higher capacity with reliable service guarantees during mobility. The sorted list of transmission schedules is used to assign physical channels in increasing order of their availability. This approach specifically encapsulates the physical layer disconnections during the handovers and ensures continuous service to ongoing flows. The proposed scheduling scheme is supplemented by an analytical model and simulations to verify its efficacy. The simulation results demonstrate higher degree of reliability and scalability of service provisioning to flows during mobility.     

Comment on ‘Discussion on Barkhausen and Nyquist stability criteria’

This comment is related to the recently published article entitled “On ‘Discussion on Barkhausen and Nyquist stability criteria’, Analog Integrated circuits and signal processing, Vol. 70, pp. 443–449, 2012. In this article the authors considered one of the possible four alternatives of the Wien-bridge oscillator that was previously considered in the article entitled “Discussion on Barkhausen and Nyquist stability criteria”, Analog Integrated Circuits and Signal Processing, Vol. 62, pp. 327–332, 2010, which depicts the failure of Barkhausen criterion concerning the determination of the condition of oscillation startup of sinusoidal oscillation. In the above mentioned articles the operational amplifier used is assumed ideal. In this comment it will be shown that the Wien-bridge oscillator circuit used in the above mentioned articles can behave as a sinusoidal oscillator only at relatively high frequencies when the operational amplifier can be considered non-ideal. At relatively low frequencies; when the operational amplifier can be considered ideal, the same circuit behaves as a relaxation oscillator with a square wave output rather than a sinusoidal output.     

Beta glucan: a valuable functional ingredient in foods

β-Glucan is a valuable functional ingredient and various extraction techniques are available for its extraction. Choice of an appropriate extraction technique is important as it may affect the quality, structure, rheological properties, molecular weight, and other functional properties of the extracted β-glucan. These properties lead to the use of β-glucan into various food systems and have important implications in human health. This review focuses on the extraction, synthesis, structure, molecular weight, and rheology of β-glucan. Furthermore, health implications and utilization of β-glucan in food products is also discussed.     

MRT Letter: Guided filtering of image focus volume for 3D shape recovery of microscopic objects

In this letter, a shape from focus (SFF) method is proposed that utilizes the guided image filtering to enhance the image focus volume efficiently. First, image focus volume is computed using a conventional focus measure. Then each layer of image focus volume is filtered using guided filtering. In this work, the all‐in‐focus image, which can be obtained from the initial focus volume, is used as guidance image. Finally, improved depth map is obtained from the filtered image focus volume by maximizing the focus measure along the optical axis. The proposed SFF method is efficient and provides better depth maps. The improved performance is highlighted by conducting several experiments using image sequences of simulated and real microscopic objects. The comparative analysis demonstrates the effectiveness of the proposed SFF method. Microsc. Res. Tech. 77:959–963, 2014. © 2014 Wiley Periodicals, Inc.     

Single‐cell protein production through microbial conversion of lignocellulosic residue (wheat bran) for animal feed

Agricultural residue (wheat bran) rich in carbohydrates was utilized in the fermentation process to produce microbial biomass. Single‐cell biomass consists of the dried cells of microorganisms, which are used as protein supplements in human food and in animal feed. In the present study, two different microorganisms (Candida utilis and Rhizopus oligosporus) were studied for biomass production. To enhance the nutritional contents of wheat bran, a number of different fermentation parameters (effect of inoculum size, age of inoculum, incubation period, moisture to substrate ratio and incubation temperature) were optimized. Maximum yield was obtained at an inoculum size of 10% (v/w), with the age of the inoculum being a 48 h old culture. A fermentation period of 48 h was found to give the maximum protein yield and viable counts of yeast cells and mould hyphae. The microorganisms showed good growth at 30 °C. After complete optimization of the fermentation parameters, a batch of wheat bran was fermented with C. utilis and R. oligosporus under the optimized conditions, resulting in a maximum crude protein yield of 41.02% compared with the 4.21% crude protein of the non‐fermented wheat bran. Copyright © 2015 The Institute of Brewing & Distilling     

Quantification of Mildew Damage in Soft Red Winter Wheat Based on Spectral Characteristics of Bulk Samples: A Comparison of Visible-Near-Infrared Imaging and Near-Infrared Spectroscopy

Mildew growth on wheat kernels reduces grain quality due to gray discoloration of kernels that has negative impact on the resulting flour color. Higher levels of mildew damage equate to lower levels of quality. In this study, grain spectra in the 400–1,000 (visible-shortwave-near-infrared) and 1,000–2,500-nm (near-infrared) wavelength ranges were investigated for their ability to quantify mildew damage in Soft Red Winter (SRW) wheat grown in eastern Canada. For each wavelength range, partial least squares (PLS) regression models were developed for various commonly used data pre-treatments. Spectra in the 400–1,000-nm region with a mean-centering pre-treatment were optimal for quantification of mildew damage in SRW wheat. A PLS model using this approach predicted mildew damage in an independent test sample set accurately achieving a root-mean-squared-error of 0.69 and ratio-performance-deviation of 3.84 with the classification accuracy of 96 % for predictions within ±1 level against the trained inspectors’ visual assessment of mildew damage scored on a nine-level scale.     

Effect of Drying Treatment on Physical Identification Characteristics of Irradiated Seasonings

The effect of different drying treatments such as spray drying and vacuum drying on the sensitivity of physical detection methods (photostimulated luminescence (PSL), electron spin resonance (ESR), and thermoluminescence (TL)) was investigated for four types of irradiated seasonings. The slurry feed of each seasoning was exposed to γ-ray irradiation at doses of 0, 5, 10 kGy before being subjected to drying process. Spray drying was applied to beef and soybean seasoning while garlic and broth seasoning were exposed to vacuum drying according to routine protocols adopted in the industry. The samples were analyzed by PSL as a rapid screening method followed by validated methods including ESR spectroscopy and TL analysis. The PSL photon counts drastically dropped in all irradiated samples after both drying processes. No ESR signal was obtained from any of the irradiated seasonings before or after the drying applications. All the irradiated seasoning samples produced typical TL glow curves between the specific temperature range of 150–250 °C. However, the shape, peak, and intensity of TL glow curves were greatly affected particularly after the spray drying treatment. In conclusion, the dry treatment can significantly affect the irradiation detection characteristics in seasoning samples.     

Different feed presentations affect subsequent feed sorting and rumen pH for a short period in weaned calves

The objective of this study was to investigate the short- and long-term effects of different feed presentations on feed sorting and rumen pH in weaned calves. Thirty-six weaned female calves at the age of 12 wk (78 d) were raised in pairs (18 pens; n = 6/treatment) and randomly exposed to 1 of 3 feed presentation treatments: (1) concentrate ration (CON, only exposed to concentrate); (2) separate ration (CH, exposed to concentrate and hay as separate components); and (3) mixed ration (Mix, exposed to a mixed diet containing 75% concentrate and 25% hay). After 4 wk (from d 78 to 105) on different feed presentations, all weaned calves were introduced to a novel total mixed ration (TMR) for another 12 wk (from d 106 to 189). Fresh feed and orts were sampled daily before (wk 12 to 15) and after (wk 16, 17, and 28) transitioning to a TMR diet for analysis of feed sorting. Rumen fluid was sampled in wk 12, 13, 15, 16, 17, and 28 to determine rumen pH. The performance of weaned calves was affected by the different feed presentations during the pre-changing period, such that calves fed CON had a lower dry matter intake (DMI) and average daily gain than calves fed CH and Mix diets. When calves were introduced to the Mix diet, they immediately developed a higher degree of sorting behavior against the long particle fractions. Upon transition to TMR, we did not observe any differences in the performance of calves. However, the sorting behavior established in Mix calves persisted and was similar to calves previously fed the CON diet, whereas the extent of feed sorting in calves initially fed CH was less compared with that in the other 2 treatments in wk 16 and 17. Before changing the diet was transitioned to a TMR, calves fed CON had a lower rumen pH than calves fed CH and Mix. Although rumen pH in all treatments increased to the same level after the diet changed, we observed a tendency toward lower rumen pH in calves fed Mix compared with calves fed CH at wk 17, which might have resulted from the higher degree of feed sorting in these calves. However, by the end of the experiment (wk 28), feed sorting and rumen pH were similar across all treatments. These results indicated a short-term effect of previous feed presentations on subsequent feed sorting and rumen pH, but in the long term disappeared.