A cross-layer jitter-based TCP for wireless networks

The Transmission Control Protocol (TCP) is one of the main communication protocols in the Internet, and it has been designed to provide an efficient reaction to packet loss events which are due to network congestion. Congestion is the main cause of losses in wired networks, but in today heterogeneous networks, loss events can also be introduced due to higher error rates on wireless channels, host mobility, and frequent handovers. Unfortunately, all packet losses are interpreted by TCP as a sign of congestion, triggering an inappropriate reaction which reduces its transmission rate and leads to performance degradation. In order to avoid this problem, it is important for TCP to correctly understand whether the reason of a packet loss is due to congestion or to a problem in the wireless link. This paper presents an innovative jitter-based cross-layer TCP algorithm, named XJTCP. It adopts the jitter ratio as loss predictor, joined with a layer two notification, in order to correctly infer the nature of a loss event. Performance evaluation and comparison with other common TCP implementations shows how XJTCP can be an interesting solution in the presence of wireless environments

Development of microfluidic cell culture technology for the study of type 2 diabetes

Type 2 Diabetes Mellitus (T2DM) is a multi-factorial disease due to metabolic disorder with injuries in glucose homeostasis and body’s glucose uptake. The complexity of this disease led to the use of different classes of drugs acting with different mechanisms and targets and with effects that often change between patients. The number of people in the world with diagnosed T2DM is constantly increasing and consequently the cost for healthcare. Nowadays, a defined cure for T2DM patients has been not clearly identified. In the study of diabetes, animal models are one of the most popular systems used to underline its pathogenesis and to screen new drugs before clinical trials on humans. Even though their undeniable utility, they showed many limitations. Moreover, studies in vivo in humans are possible but tremendously expensive and require a huge effort in terms of ethical approval and safety issues. Therefore in vivo studies often do not permit an evaluation at specific tissue level: their interplay complexity allow a very difficult outcome interpretation. For all these reasons there is a great interest in developing alternative in vitro models that facilitate pharmaceutical and pathology studies. Thus, the aim of this thesis is the development of an in vitro model that closely resemble the human physiology and mimic the pathophysiological conditions of type 2 diabetes. In particular, this work concerns the design and development of microfluidic technology for the study of insulin resistance and glucose uptake in cell and tissue culture from Type 2 Diabetes patients. High temporal resolution glucose uptake measurements were achieved by coupling microfluidic technologies and glucose detection measurements with a non invasive manner. The technology was applied to skeletal muscle and ex vivo adipose tissue, with the obtainment of high sensitive and reproducible experiments. During this PhD, a microfluidic platform was developed and fabricated with multilayer soft lithography techniques. The platform was able to integrate 2D (cells) and 3D (ex vivo tissue) culture allowing long term viability and metabolic activity. High experiment feasibility was achieved by the long term culture capability. Micro components were included into the device allowing automation and liquid handling control. Integrated microvalves and micropumps allowed the development of injection systems for high spatio temporal control of biochemical stimulus delivery, such as insulin and other anti-diabetic drugs. Glucose uptake was investigated measuring high temporal resolution glucose concentration in the downstream culture chamber medium by high sensitive analytical measurements on nanoliter sampling, providing glucose dynamic with temporal resolution of minutes. The measurement of intracellular glucose concentration was evaluated by encoded FRET nanosensor. The coupling between intracellular and extracellular glucose detection allowed the determination of novel glucose uptake and glycolytic rate evaluation technique within the cell. These results show a good potential in future pharmaceutical and clinical experimentation, in which the use of a microfluidic ex vivo human patient assays could be useful in drug screening studies and patient specific therapies

In Situ Raman Analysis of CO\u2082-Assisted Drying of Fruit-Slices

This work explores the feasibility of applying in situ Raman spectroscopy for the online monitoring of the supercritical carbon dioxide (SC-CO\u2082) drying of fruits. Specifically, we investigate two types of fruits: mango and persimmon. The drying experiments were carried out inside an optical accessible vessel at 10 MPa and 313 K. The Raman spectra reveal: (i) the reduction of the water from the fruit slice and (ii) the change of the fruit matrix structure during the drying process. Two different Raman excitation wavelengths were compared: 532 nm and 785 nm. With respect to the quality of the obtained spectra, the 532 nm excitation wavelength was superior due to a higher signal-to-noise ratio and due to a resonant excitation scheme of the carotenoid molecules. It was found that the absorption of CO\u2082 into the fruit matrix enhances the extraction of water, which was expressed by the obtained drying kinetic curve

Inactivation of Salmonella , Listeria monocytogenes and Escherichia coli O157:H7 inoculated on coriander by freeze-drying and supercritical CO 2 drying

Coriander, either fresh or inoculated with three strains of Escherichia coli O157:H7, Salmonella or Listeria monocytogenes, was treated with supercritical CO2 (scCO(2), with and without drying) or freeze-dried. After drying in scCO(2) for 150 min at 80 bar and 35 degrees C, the aerobic plate count, yeasts and molds, and the Enterobacteriaceae were reduced by 2.80, 5.03, and 4.61 log CFU/g, respectively. The total count of mesophilic aerobic spores was not significantly reduced by the treatment. Freeze-drying induced lower reductions with 1.23, 0.87, and 0.97 log CFU/g, respectively. After treatment at 100 bar and 40 degrees C without drying, inoculated strains of E. coli O157:H7, Salmonella, and L. monocytogenes were inactivated by > 7.37, > 4.73 and 4.99 log CFU/g, respectively. After drying in scCO 2 for 150 min at 80 bar and 35 degrees C, the strains were reduced by > 5.18 log CFU/g. Freeze-drying resulted in lower reduction with maximum 1.53, 2.03, and 0.71 log CFU/g, respectively. This study indicated that scCO(2) can be used for drying while offering a good inactivation of E. coli O157:H7, Salmonella, and L. monocytogenes as well as most of the bacteria in the vegetative form naturally occurring on coriander. Industrial relevance: Although dried foods are considered microbiological stable foods and show adverse conditions to microbial growth, they may still host pathogenic microorganisms, which may proliferate upon sufficient rehydration. Highly contaminated commodities such as herbs and spices can pose a threat to consumer health if not processed carefully. There is therefore a need to develop or improve drying techniques which can provide dried foods while reducing the initial contamination to acceptable levels in a single process. CO2 is a cheap, accessible solvent, with a low critical point (31 degrees C, 73.8 bar). Moreover, in the supercritical region, CO, exhibits potent microbicidal properties. Therefore, supercritical CO2 drying could be a valuable alternative nonthermal technique for conventional drying methods, such as air-drying or freeze-drying, when medium to high value-added food products with high initial contamination are involved

Simvastatin Rapidly and Reversibly Inhibits Insulin Secretion in Intact Single-Islet Cultures

open10Epidemiological studies suggest that statins may promote the development or exacerbation of diabetes, but whether this occurs through inhibition of insulin secretion is unclear. This lack of understanding is partly due to the cellular models used to explore this phenomenon (cell lines or pooled islets), which are non-physiologic and have limited clinical transferability.openScattolini, Valentina; Luni, Camilla; Zambon, Alessandro; Galvanin, Silvia; Gagliano, Onelia; Ciubotaru, Catalin Dacian; Avogaro, Angelo; Mammano, Fabio; Elvassore, Nicola; Fadini, Gian PaoloScattolini, Valentina; Luni, Camilla; Zambon, Alessandro; Galvanin, Silvia; Gagliano, Onelia; Ciubotaru, CATALIN DACIAN; Avogaro, Angelo; Mammano, Fabio; Elvassore, Nicola; Fadini, GIAN PAOL

Microbial inactivation of raw chicken meat by supercritical carbon dioxide treatment alone and in combination with fresh culinary herbs

The objective of the present study was to assess the potential synergistic effect between supercritical carbon dioxide (SC-CO2) and fresh culinary herbs (Coriandrum sativum and Rosmarinus officinalis) on the microbial inactivation of raw chicken meat. The microbiological inactivation was performed on Escherichia coli and natural flora (total mesophilic bacteria, yeasts, and molds). High pressure treatments were carried out at 40\ub0C, 80 or 140 bar from 15 to 45 min. Microbial inactivation had a strong dependence on treatment time, achieving 1.4 log CFU/g reduction of E. coli after 15 min, and up to 5 log after 45 min, while a pressure increase from 80 up to 140 bar was not significant on the microbial inactivation. Mesophilic microorganisms were strongly reduced (>2.6 log CFU/g) after 45 min, and yeasts and molds were below the detection limits of the technique (<100 CFU/g) in most cases. The combination of fresh herbs together with SC-CO2 treatment did not significantly increase the inactivation of either E. coli or natural flora, which was similar to the SC-CO2 alone. The synergistic effect was obtained on the inactivation of E. coli using a proper concentration of coriander essential oil (EO) (0.5% v/w), while rosemary EO did not show a significant effect. Color analysis after the treatment showed an increment of lightness (L*), and a decrease of redness (a*) on the surface of the sample, making the product visually similar to cooked meat. Texture analysis demonstrated the modification of the texture parameters as a function of the process pressure making the meat more similar to the cooked one

Sarcoma risk and dioxin emissions from incinerators and industrial plants: a population-based case-control study (Italy)

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Effect of CO2 preservation treatments on the sensory quality of pomegranate juice

8openInternationalBothDue to the interest in identifying cost-effective techniques that can guarantee the microbiological, nutritional, and sensorial aspects of food products, this study investigates the effect of CO2 preservation treatment on the sensory quality of pomegranate juice at t0 and after a conservation period of four weeks at 4 °C (t28). The same initial batch of freshly squeezed non-treated (NT) juice was subjected to non-thermal preservation treatments with supercritical carbon dioxide (CO2), and with a combination of supercritical carbon dioxide and ultrasound (CO2-US). As control samples, two other juices were produced from the same NT batch: A juice stabilized with high pressure treatment (HPP) and a juice pasteurized at high temperature (HT), which represent an already established non-thermal preservation technique and the conventional thermal treatment. Projective mapping and check-all-that-apply methodologies were performed to determine the sensory qualitative differences between the juices. The volatile profile of the juices was characterized by gas chromatography-mass spectrometry. The results showed that juices treated with supercritical CO2 could be differentiated from NT, mainly by the perceived odor and volatile compound concentration, with a depletion of alcohols, esters, ketones, and terpenes and an increase in aldehydes. For example, in relation to the NT juice, limonene decreased by 95% and 90%, 1-hexanol decreased by 9% and 17%, and camphene decreased by 94% and 85% in the CO2 and CO2-US treated juices, respectively. Regarding perceived flavor, the CO2-treated juice was not clearly differentiated from NT. Changes in the volatile profile induced by storage at 4 °C led to perceivable differences in the odor quality of all juices, especially the juice treated with CO2-US, which underwent a significant depletion of all major volatile compounds during storage. The results suggest that the supercritical CO2 process conditions need to be optimized to minimize impacts on sensory quality and the volatile profile.openMosca, A.C.; Menghi, L.; Aprea, E.; Mazzucotelli, M.; Benedito, J.; Zambon, A.; Spilimbergo, S.; Gasperi, F.Mosca, A.C.; Menghi, L.; Aprea, E.; Mazzucotelli, M.; Benedito, J.; Zambon, A.; Spilimbergo, S.; Gasperi, F