Continuous-Flow UV Liquid Food Pasteurization: Engineering Aspects

Ultraviolet (UV)-C treatments are a promising technology for liquid food pasteurization as an alternative to heat treatments. However, the design of efficient UV reactors to reduce pertinent microorganisms and comply with current food safety goals is still an engineering challenge due to the low penetration depth of UV light in liquid foods with high UV absorbance and suspended particles, and the variations in the residence time of the product in the UV reactors. This review focuses on physical aspects of UV radiation related to the essential product and processing parameters for the design of UV reactors. The UV equipment available for liquid food processing is described and the main drawbacks and advantages are discussed.     

Orthostatic postural tachycardia: study of 8 patients

Foreign body aspiration (FBA) is a leading cause of accidental death in children less than one year old and is the cause of death in 7% of children less than four. Food items, especially peanuts, are the most common items aspirated in infants and toddlers, whereas older children are more likely to aspirate non-food items such as pen caps, pins, and paper clips. A high degree of suspicion is required to diagnose FBA. A history of a witnessed choking episode is most important in early diagnosis. An asymptomatic period is common after aspiration and contributes to a delay in diagnosis of greater than one week in 12% to 26% of patients. This delay in diagnosis causes increased morbidity from bronchial inflammation, obstruction, and pneumonia which is resistant to treatment. Prompt endoscopic removal of the foreign body with an open rigid bronchoscope under general anesthesia is the mainstay of therapy.     

Barriers and drivers for non-shoppers in B2C e-commerce: A latent class exploratory analysis

The barriers and drivers of e-shopping, as well as segmentation and behavior of e-shoppers, have been long studied in the last two decades, but the behavior of non-shoppers in business-to-consumer (B2C) e-commerce is still an open field for research which has seldom been dealt with. Our exploratory study has as its main objective the classification of non-shoppers in B2C e-commerce based on the barriers which keep deterring them from purchasing on the Internet and the drivers which might lead them to engage in e-shopping. In order to achieve this goal, data was gathered from 1499 Spanish respondents from a nationwide household panel survey. The responses were analyzed using a latent class analysis (LCA) approach and the results show four different types of non-shoppers based on the barriers for online shopping, while six different groups were identified based on the drivers to start shopping on the Internet. Implications for research and practice from the findings of the study are discussed in the final section.     

Highly Hydrophilic and Lipophilic Derivatives of Bile Salts

Lipophilicity of 15 derivatives of sodium cholate, defined by the octan-1-ol/water partition coefficient (log P), has been theoretically determined by the Virtual log P method. These derivatives bear highly hydrophobic or highly hydrophilic substituents at the C3 position of the steroid nucleus, being linked to it through an amide bond. The difference between the maximum value of log P and the minimum one is enlarged to 3.5. The partition coefficient and the critical micelle concentration (cmc) are tightly related by a double-logarithm relationship (VirtuallogP=−(1.00±0.09)log(cmcmM)+(2.79±0.09)), meaning that the Gibbs free energies for the transfer of a bile anion from water to either a micelle or to octan-1-ol differ by a constant. The equation also means that cmc can be used as a measurement of lipophilicity. The demicellization of the aggregates formed by three derivatives of sodium cholate bearing bulky hydrophobic substituents has been studied by surface tension and isothermal titration calorimetry. Aggregation numbers, enthalpies, free energies, entropies, and heat capacities, ΔC_P,demic, were obtained. ΔC_P,demic, being positive, means that the interior of the aggregates is hydrophobic.     

PP1, PP2A and PP2B Interplay in the Regulation of Sperm Motility: Lessons from Protein Phosphatase Inhibitors

Male fertility relies on the ability of spermatozoa to fertilize the egg in the female reproductive tract (FRT). Spermatozoa acquire activated motility during epididymal maturation; however, to be capable of fertilization, they must achieve hyperactivated motility in the FRT. Extensive research found that three protein phosphatases (PPs) are crucial to sperm motility regulation, the sperm-specific protein phosphatase type 1 (PP1) isoform gamma 2 (PP1γ2), protein phosphatase type 2A (PP2A) and protein phosphatase type 2B (PP2B). Studies have reported that PP activity decreases during epididymal maturation, whereas protein kinase activity increases, which appears to be a requirement for motility acquisition. An interplay between these PPs has been extensively investigated; however, many specific interactions and some inconsistencies remain to be elucidated. The study of PPs significantly advanced following the identification of naturally occurring toxins, including calyculin A, okadaic acid, cyclosporin, endothall and deltamethrin, which are powerful and specific PP inhibitors. This review aims to overview the protein phosphorylation-dependent biochemical pathways underlying sperm motility acquisition and hyperactivation, followed by a discussion of the PP inhibitors that allowed advances in the current knowledge of these pathways. Since male infertility cases still attain alarming numbers, additional research on the topic is required, particularly using other PP inhibitors.     

Numerical analysis of a DAR IMPATT diode

The analysis and optimization of the n ⁺ pvnp ⁺ avalanche diode structure that includes two avalanche regions have been realized on basis of the nonlinear model and special optimization procedure. The admittance and energy characteristics of the DAR diode were analyzed in very wide frequency band from 30 up to 360 GHz. Output power level was optimized for the second frequency band near the 220 GHz.     

Digital Control of a Power Conditioner for Fuel Cell/Super-capacitor Hybrid System

This article proposes a digital control scheme to operate a proton exchange membrane fuel cell module of 1.2 kW and a super-capacitor through a DC/DC hybrid converter. A fuel cell has been proposed as a primary source of energy, and a super-capacitor has been proposed as an auxiliary source of energy. Experimental validation of the system implemented in the laboratory is provided. Several tests have been performed to verify that the system achieves excellent output voltage (V₀) regulation and super-capacitor voltage (V_SC) control under disturbances from fuel cell power (P_FC) and output power (P₀) as well as other perturbations described in analysis results.     

Synthesis of low molecular weight polyethylenes and polyethylene mimics with controlled chain structures

The controlled synthesis of narrowly distributed low molecular weight polymers with functionalization possibilities is of great industrial interests. Although living polymerization allows for control over polymer architecture, the production of low molecular weight polymers with low polydispersities via living polymerization systems is challenged by the use of large amounts of catalysts and broadening in molecular weight distribution. This review addresses the synthesis of narrowly distributed, functional, low molecular weight polyethylene and polyethylene mimics. The review is structured for quick identification of relevant systems for the production of specific polymer architectures with specific cost, efficiency, and safety concerns.     

Biosurfactant-and-Bioemulsifier Produced by a Promising Cunninghamella echinulata Isolated from Caatinga Soil in the Northeast of Brazil

A Mucoralean fungus was isolated from Caatinga soil of Pernambuco, Northeast of Brazil, and was identified as Cunninghamella echinulata by morphological, physiological, and biochemical tests. This strain was evaluated for biosurfactant/bioemulsifier production using soybean oil waste (SOW) and corn steep liquor (CSL) as substrates, added to basic saline solution, by measuring surface tension and emulsifier index and activity. The best results showed the surface water tension was reduced from 72 to 36 mN/m, and an emulsification index (E₂₄) of 80% was obtained using engine oil and burnt engine oil, respectively. A new molecule of biosurfactant showed an anionic charge and a polymeric chemical composition consisting of lipids (40.0% w/w), carbohydrates (35.2% w/w) and protein (20.3% w/w). In addition, the biosurfactant solution (1%) demonstrated its ability for an oil displacement area (ODA) of 37.36 cm², which is quite similar to that for Triton X-100 (38.46 cm²). The stability of the reduction in the surface water tension as well as of the emulsifier index proved to be stable over a wide range of temperatures, in pH, and in salt concentration (4%–6% w/v). The biosurfactant showed an ability to reduce and increase the viscosity of hydrophobic substrates and their molecules, suggesting that it is a suitable candidate for mediated enhanced oil recovery. At the same time, these studies indicate that renewable, relatively inexpensive and easily available resources can be used for important biotechnological processes.