Design of a low frequency ultrasonic microreactor

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Managing solids in micro/mini flow reactors by ultrasound

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A low-frequency ultrasound reactor for continuous flow for precipitation reactions

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Pulsed ultrasound for temperature control and clogging prevention in micro-reactors

Ultrasonic micro-reactors are frequently applied to prevent micro-channel clogging in the presence of solid materials. Continuous sonication will lead to a sizeable energy input resulting in a temperature increase in the fluidic channels and concerns regarding microchannel degradation. In this paper, we investigate the application of pulsed ultrasound as a less invasive approach to prevent micro-channel clogging, while also controlling the temperature increase. The inorganic precipitation of barium sulfate particles was studied, and the impact of the effective ultrasonic treatment ratio, frequency and load power on the particle size distribution, pressure and temperature was quantified in comparison to non-sonicated experiments. The precipitation reactions were performed in a continuous reactor consisting of a micro-reactor chip attached to a Langevin-type transducer. It was found that adjusting the pulsed ultrasound conditions prevented microchannel clogging by reducing the particle size to the same magnitude as observed for continuous sonication. Furthermore, reducing the effective treatment ratio from 100 to 12.5% decreases the temperature rise from 7 to 1 °C.status: publishe

Design and Characterization of a Scaled-up Ultrasonic Flow Reactor

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Continuous Ultrasonic Reactors: Design, Mechanism and Application

Ultrasonic small scale flow reactors have found increasing popularity among researchers as they serve as a very useful platform for studying and controlling ultrasound mechanisms and effects. This has led to the use of these reactors for not only research purposes, but also various applications in biological, pharmaceutical and chemical processes mostly on laboratory and, in some cases, pilot scale. This review summarizes the state of the art of ultrasonic flow reactors and provides a guideline towards their design, characterization and application. Particular examples for ultrasound enhanced multiphase processes, spanning from immiscible fluid-fluid to fluid-solid systems, are provided. To conclude, challenges such as reactor efficiency and scalability are addressed.status: publishe

Prolonged inflammatory gene response following soman-induced seizures in mice.

International audienceFollowing exposure to the organophosphorus nerve agent soman, the development of long-lasting seizures and build-up of irreversible seizure-related brain damage (SRBD) still represent a therapeutic challenge. A neuro-inflammatory reaction takes place in the brain after poisoning but its characteristics and potential role in SRBD and post-status epilepticus epileptogenesis is not well understood. In the present study we have analyzed by quantitative RT-PCR the time course of changes in mRNA levels of IL-1beta, TNFalpha, IL-6, ICAM-1 and SOCS3 in hippocampus, whole cortex and cerebellum in a mouse model of severe seizures and neuropathy up to 7 days after poisoning. Mice received an injection of the oxime HI-6 (50mg/kg) 5 min prior to the administration of a convulsive dose of soman (172 microg/kg). An important and highly significant increase of the five mRNA levels was recorded in cortex and hippocampus. In the cortex, the activation was generally detected as early as 1h post-intoxication with a peak response recorded between 6 and 24h. In the hippocampus, the gene up-regulation was delayed to 6h post-soman and the peak response observed between 24 and 48 h. After peaking, the response declined (except for ICAM in the hippocampus) but remained elevated, some of them significantly, at day 7. Interestingly, in the cerebellum, some changes were also observed but were several fold smaller. In conclusion, the present study indicates a quick neuro-inflammatory gene response that does not subside over 7 days suggesting a potential role in the neurological consequences of soman-induced status epilepticus

Cerebral edema induced in mice by a convulsive dose of soman. Evaluation through diffusion-weighted magnetic resonance imaging and histology.

International audiencePURPOSE: In the present study, diffusion-weighted magnetic resonance imaging (DW-MRI) and histology were used to assess cerebral edema and lesions in mice intoxicated by a convulsive dose of soman, an organophosphate compound acting as an irreversible cholinesterase inhibitor. METHODS: Three hours and 24 h after the intoxication with soman (172 microg/kg), the mice were anesthetized with an isoflurane/N(2)O mixture and their brain examined with DW-MRI. After the imaging sessions, the mice were sacrificed for histological analysis of their brain. RESULTS: A decrease in the apparent diffusion coefficient (ADC) was detected as soon as 3 h after the intoxication and was found strongly enhanced at 24 h. A correlation was obtained between the ADC change and the severity of the overall brain damage (edema and cellular degeneration): the more severe the damage, the stronger the ADC drop. Anesthesia was shown to interrupt soman-induced seizures and to attenuate edema and cell change in certain sensitive brain areas. Finally, brain water content was assessed using the traditional dry/wet weight method. A significant increase of brain water was observed following the intoxication. CONCLUSIONS: The ADC decrease observed in the present study suggests that brain edema in soman poisoning is mainly intracellular and cytotoxic. Since entry of water into the brain was also evidenced, this type of edema is certainly mixed with others (vasogenic, hydrostatic, osmotic). The present study confirms the potential of DW-MRI as a non-invasive tool for monitoring the acute neuropathological consequences (edema and neurodegeneration) of soman-induced seizures

Association between physical activity and nocturnal leg cramps in patients over 60 years old: a case-control study

Nocturnal Legs Cramps are a frequent disorder, which have a negative impact on quality of life, particularly among patients over 60 years old. Lifestyle factors such as alcohol consumption have been shown to be associated with Nocturnal Leg Cramps. This study aimed to explore the association between nocturnal leg cramps and a sedentary lifestyle among elderly patients. A case-control study was conducted with a Bayesian approach for sensitivity analysis. Patients over 60 years old consulting their family doctor were recruited in the Alsace region, France. Cases were matched with controls free from cramps for age, sex, medical history and medications known to trigger cramps. The level of physical activity was assessed using the Dijon Physical Activity Score (DPAS). We performed univariate and multivariate analyses adjusting for alcohol consumption. 272 participants were matched into 136 pairs. 11% of all were sedentary persons. Adjusting for alcohol consumption, we observed an association between Nocturnal Leg Cramps and a sedentary lifestyle OR = 9.84 (95% credibility interval [1.74; 101.9]; posterior probability 99.68%). Our findings represent an additional argument to promote physical activity to patients over 60 years old. They also highlight the need to develop and evaluate physical activity interventions in the treatment of Nocturnal Legs Cramps

Association Between Alcohol Consumption and Nocturnal Leg Cramps in Patients Over 60 Years Old: A Case-Control Study

PURPOSE Nocturnal leg cramps are a specific kind of cramps affecting almost one-half of patients aged 60 years and older. They reduce patients' quality of sleep and have a negative impact on their quality of life. The aim of this study was to evaluate the association between nocturnal leg cramps and the consumption of alcoholic beverages in patients aged 60 years and older attending general practices. METHODS Case-control study with a Bayesian approach for sensitivity analysis. Participants were voluntary ambulatory patients aged 60 years and older consulting their family doctor. They were recruited in 67 general practices across the Alsace region. Cases (patients having cramps), were matched with controls (patients free from cramps) for age, sex, medical history, and medications known to trigger cramps. Alcohol consumption was assessed through a standardized food frequency questionnaire. RESULTS We found an association between the global consumption of alcoholic beverages and nocturnal leg cramps (OR = 6.5, 95% credibility interval, 1.68- 38.05; posterior probability 99.82%). CONCLUSION We identified an association between alcohol consumption and nocturnal leg cramps among patients aged 60 years and older attending general practices. These findings have implications for the prevention of cramps