Characterization of the biocide polyhexamethylene biguanide by matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry

The biocide polyhexamethylene biguanide (PHMB) has been characterized by matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS). Previously, no method has been able to provide a detailed structural characterization of PHMB. MALDI‐TOF MS was able to detect PHMB oligomers with n ≤ 6. Six different PHMB product types were identified, which possess combinations of amine, cyanoamine, guanidine, or cyanoguanidine end‐groups. Postsource decay (PSD) fragmentation was used to confirm the correct assignment of PHMB structure for the dominant PHMB molecular ion. MALDI‐TOF MS analysis of a ¹⁵N‐labeled PHMB confirmed the correct assignment of PHMB molecular ions, and also indicated the existence of a polymerization–depolymerization equilibrium during melt polymerization of the polymer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4928–4936, 2006     

Stochastic price modeling of high volatility, mean-reverting, spike-prone commodities: The Australian wholesale spot electricity market

It is commonly known that wholesale spot electricity markets exhibit high price volatility, strong mean-reversion and frequent extreme price spikes. This paper employs a basic stochastic model, a mean-reverting model and a regime-switching model to capture these features in the Australian national electricity market (NEM), comprising the interconnected markets of New South Wales, Queensland, South Australia and Victoria. Daily spot prices from 1 January 1999 to 31 December 2004 are employed. The results show that the regime-switching model outperforms the basic stochastic and mean-reverting models. Electricity prices are also found to exhibit stronger mean-reversion after a price spike than in the normal period, and price volatility is more than fourteen times higher in spike periods than in normal periods. The probability of a spike on any given day ranges between 5.16% in NSW and 9.44% in Victoria.     

Expression of mouse immunoglobulin light and heavy chain variable regions in Escherichia coli and reconstitution of antigen-binding activity

The expression of immunoglobulin heavy and light chain variableregions in the cytoplasm of Escherichia coli and formation ofa functional heterodimer has been demonstrated. Variable domainsequences were taken from the heavy and light chain cDNAs ofthe monoclonal antibody Gloop 2 and engineered for expressionin a dual origin expression vector. The engineered genes vhg2and vlg2 were separately subcloned into the vector, creatingtwo expression plasmids. Expression of the heavy and light chainvariable region genes (encoding 116 and 109 amino adds respectively)was investigated in eight E.coli strains; the polypeptides wererapidly degraded in a host strain optimized for expression andin E.coli strains deficient in the major protease La (lon^-).Accumulation was permitted in severely protease-deficient E.colihaving a defective heat-shock response. A lon^- mutation in thisgenetic background permitted even higher accumulation. Expressionlevels were 7 and 1% of total bacterial protein for light andheavy chain variable regions respectively. Expression of theheavy chain variable region gene was increased by includinga longer Shine–Dalgarno sequence. Similar constructionsin the light chain vector had no effect on expression levels.The insoluble variable region polypeptides were reconstitutedinto a heterodimer possessing the full antigen binding characteristicsof both the parent monoclonal antibody and its Fab fragment.     

Epidemiologie des EHEC O104:H4/HUS-Ausbruchs in Deutschland, Mai bis Juli 2011

From May to July 2011 the largest outbreak of infections with enterohemorrhagic Escherichia coli (EHEC) O104:H4 and hemolytic uremic syndrome (HUS) reported to date with more than 3,800 diseased persons and 53 deaths occurred mainly in Northern Germany. Infections predominantly affected adults. This contrasts EHEC gastroenteritis and HUS surveillance data of previous years when mainly children where affected. In relation to disease onset (symptoms of diarrhea) of reported cases, the outbreak began on 8 May 2011, peaked on 22 May, and then subsided. On 26 July 2011, the outbreak was declared to be over by the Robert Koch Institute (RKI), because at this point in time new cases that were obviously associated with the outbreak and had a disease onset after 4 July had not been reported in the three previous weeks. Epidemiological studies of the RKI in cooperation with local and state public health authorities and hospitals as well as investigations by food safety authorities identified contaminated sprouts from producer A in Lower Saxony and, more specifically, imported fenugreek seeds used for sprout cultivation as the most likely vehicle of infection. Close cooperation between health and food safety authorities during the outbreak investigation was essential for solving the outbreak within a short timeframe.     

CONEXPO-CON/AGG 2005与IFPE2005早知道

2005年美国拉斯维加斯工程建设机械博览会（CONEXPO—CON／AGG2005)和2005年美国国际动力传动博览会(IFPE2005)将于2005年3月15～19日在美国内华达州拉斯维加斯会展中心举行。这将是2005年全球建设机械、建筑材料和动力传动行业最大规模的盛会．将有来自120个国家和地区的超过10万名的专业观众参观展会。     

How to Heal the Gut’s Brain: Regeneration of the Enteric Nervous System

The neural-crest-derived enteric nervous system (ENS) is the intrinsic nervous system of the gastrointestinal (GI) tract and controls all gut functions, including motility. Lack of ENS neurons causes various ENS disorders such as Hirschsprung Disease. One treatment option for ENS disorders includes the activation of resident stem cells to regenerate ENS neurons. Regeneration in the ENS has mainly been studied in mammalian species using surgical or chemically induced injury methods. These mammalian studies showed a variety of regenerative responses with generally limited regeneration of ENS neurons but (partial) regrowth and functional recovery of nerve fibers. Several aspects might contribute to the variety in regenerative responses, including observation time after injury, species, and gut region targeted. Zebrafish have recently emerged as a promising model system to study ENS regeneration as larvae possess the ability to generate new neurons after ablation. As the next steps in ENS regeneration research, we need a detailed understanding of how regeneration is regulated on a cellular and molecular level in animal models with both high and low regenerative capacity. Understanding the regulatory programs necessary for robust ENS regeneration will pave the way for using neural regeneration as a therapeutic approach to treating ENS disorders.     

Effects of Carbonation on Probiotic Survivability,Physicochemical, and Sensory Properties of Milk‐Based Symbiotic Beverages

Drinkable yogurt is a popular beverage in the United States and there may be a niche for carbonated drinkable yogurt in the functional foods market. Pomegranate (P) and vanilla (V) yogurt beverages were formulated, containing inulin as a prebiotic, along with probiotic bacteria Lactobacillus acidophilus and Bifidobacterium, to produce symbiotic products. These beverages were stabilized with high‐methoxyl pectin and whey protein concentrate and compared to samples with approximately 2 volumes of added carbon dioxide (CO₂). Samples were stored in sealed glass bottles at 4 °C for 9 wk for evaluation of physicochemical and functional properties. Trials were carried out in triplicate and 3 replicates from each trial were analyzed. Physicochemical attributes were analyzed using standard AOAC methods. Survivability of the probiotics and changes in pH and viscosity were measured weekly. Chemical composition of the carbonated beverages was: protein: 1.58 ± 0.05%, 1.59 ± 0.06%, fat: 1.24 ± 0.2%, 1.18 ± 0.11%, total solids: 14.78 ± 0.11%, 14.93 ± 0.05%, ash: 0.49 ± 0.02%, 0.46 ± 0.03%, and carbohydrate (by difference): 11.47 ± 0.12%, 11.69 ± 0.14% for P and V, respectively. Both L. acidophilus and Bifidobacterium were stable and remained above 10⁶ CFU/g for both flavors of beverage both with and without carbonation. The new manufacturing technology for these prototypes may have potential for commercialization of carbonated symbiotic milk‐based beverages.     

Delayed harvest reduces quality of raw and roasted macadamia kernels

BACKGROUND: Macadamia integrifolia, M. tetraphylla and their hybrids are cultivated for their edible kernels. Abscised macadamia fruit is gathered from the ground, and harvest intervals vary due to management decisions or unavoidable delays. In this study, macadamia fruit from cultivar HAES 344 was harvested between May and August in three experiments in south‐east Queensland, Australia. Control fruit was dehusked, dried and evaluated immediately, while delayed harvest fruit remained on the ground under trees for periods of 3 and 5 weeks before processing. Whole kernel weight, shoulder damage and weight of pieces were assessed for raw kernels, and kernel colour mottled colour and surface damage were assessed after roasting. RESULTS: Delaying harvest for 3 weeks in experiment 1, and 3 or 5 weeks in experiment 2 reduced whole kernel and increased shoulder damage and weight of pieces. Experiment 3 raw kernel was not affected. After‐roast darkening increased in all experiments, and roasting produced severe mottled colour in one experiment, and severe surface damage in two of three experiments. CONCLUSION: Macadamia kernels may deteriorate rapidly when harvest is delayed, and both raw and roasted kernel quality may be affected. Shorter harvest intervals, preferably less than 3 weeks, will help maintain optimum kernel quality. Copyright © 2008 Society of Chemical Industry     

Understanding the impact of crop and food production on the water environment—using sugar as a model

The availability of fresh water and the quality of aquatic ecosystems are important global concerns, and agriculture plays a major role. Consumers and manufacturers are increasingly sensitive to sustainability issues related to processed food products and drinks. The present study examines the production of sugar from the growing cycle through to processing to the factory gate, and identifies the potential impacts on water scarcity and quality and the ways in which the impact of water use can be minimised. We have reviewed the production phases and processing steps, and how calculations of water use can be complicated, or in some cases how assessments can be relatively straightforward. Finally, we outline several ways that growers and sugar processors are improving the efficiency of water use and reducing environmental impact, and where further advances can be made. This provides a template for the assessment of other crops. © 2013 Society of Chemical Industry     

Conjugated Polymer for Voltage‐Controlled Release of Molecules

Conjugated polymers are attractive in numerous biological applications because they are flexible, biocompatible, cost‐effective, solution‐processable, and electronic/ionic conductive. One interesting application is for controllable drug release, and this has been realized previously using organic electronic ion pumps. However, organic electronic ion pumps show high operating voltages and limited transportation efficiency. Here, the first report of low‐voltage‐controlled molecular release with a novel organic device based on a conjugated polymer poly(3‐hexylthiophene) is presented. The releasing rate of molecules can be accurately controlled by the duration of the voltage applied on the device. The use of a handy mobile phone to remotely control the releasing process and its application in delivering an anticancer drug to treat cancer cells are also successfully demonstrated. The working mechanism of the device is attributed to the unique switchable permeability of poly(3‐hexylthiophene) in aqueous solutions under a bias voltage that can tune the wettability of poly(3‐hexylthiophene) via oxidation or reduction processes. The organic devices are expected to find many promising applications for controllable drug delivery in biological systems.