Silicon straight tube fluid density sensor

In this paper, a micromachined silicon straight tube is tested as a fluid density sensor. In comparison with other density measurement techniques, the use of micromachined tubes require small sample volumes and allows continuous monitoring of the fluid density in microfluidic systems. Different vibration modes of the sensor were detected and calibrated using a laser Doppler vibrometer (LDV). Linearity, simplicity, the straightforward fabrication and evaluation, the low flow restriction and reduced risk of trapping gas in the sensor due the absence of corners are the design's main advantages. The ability of the sensor to measure density of multiphase fluids and provide accurate results independent of other fluid parameters, allows it to be used in varying fields such as the biomedical, pharmaceutical and petrochemical industries

A silicon straight tube fluid density sensor

In this paper, a new and simple silicon straight tube is tested as a fluid density sensor. The tube structure has a hexagonal cross section. The fabrication process consists of anisotropic silicon etching and silicon fusion bonding. A tube structure with a length of 2.65 cm was tested. The sample volume is 9.3 μL. The first three modes of vibrations were investigated with a laser Doppler vibrometer for air and five liquid mixtures. The fluid density sensitivity of each mode was measured and the average was −256 ± 6 ppm (kg m−3)−1 around the density of water. The density of an unknown fluid can be continuously monitored using this sensor by measuring the resonance frequency of one of the vibration modes and extracting the density from the calibration curves

Silicon straight tube fluid density sensor

In this paper, a micromachined silicon straight tube is tested as a fluid density sensor. In comparison with other density measurement techniques, the use of micromachined tubes require small sample volumes and allows continuous monitoring of the fluid density in microfluidic systems. Different vibration modes of the sensor were detected and calibrated using a laser Doppler vibrometer (LDV). Linearity, simplicity, the straightforward fabrication and evaluation, the low flow restriction and reduced risk of trapping gas in the sensor due the absence of corners are the design's main advantages. The ability of the sensor to measure density of multiphase fluids and provide accurate results independent of other fluid parameters, allows it to be used in varying fields such as the biomedical, pharmaceutical and petrochemical industries

MEMS meander harvester with tungsten proof-mass

Using current battery technology the life-time of a leadless pacemaker is approximately 6-10 years, with a large portion of the pacemaker occupied by the battery. This paper investigates the possibility to use a MEMS piezoelectric harvester as a complementary energy source in leadless pacemakers. The challenge is to combine the low resonance frequency required to harvest energy from a heartbeat with the small volume of 20 74 73 mm3 available, with the corresponding harvester displacement restricted to 2 mm. Due to the displacement restriction the selected structure was a double clamped bridge in order to reduce the mass displacement, with various meander-type designs simulated to reduce resonance frequency. To further reduce resonance frequency large proof-masses of tungsten were attached by gluing. Two types of tungsten proof-masses were added to four different harvesters, 16.4 mg and 16.6 mg on sample 1 and 2 and 502 mg and 492 mg proof-mass on sample 3 and 4. The structures have 2 μm patterned PZT (deposited by sol-gel technique) and Pt metal electrodes for d31 mode harvesting. The power output measured from one of the two PZT/electrodes was 0.13 nW with 50 μm deflection at 100 k Ω optimal load resistance and 9.1 mVpp at 232 Hz

Local metabolic changes in subcutaneous adipose tissue during intravenous and epidural analgesia.

BACKGROUND: This clinical study aimed at investigating the impact of postoperative thoracic epidural analgesia on extracellular glycerol concentration and glucose metabolism in subcutaneous adipose tissue, using the microdialysis technique. The sympathetic nervous activity, which can be attenuated by epidural anesthesia, influences lipolysis and the release of glycerol. METHODS: Fourteen patients who underwent major abdominal or thoraco-abdominal surgery were studied postoperatively over 3 days. For postoperative analgesia the patients were prospectively randomized to receive either thoracic epidural analgesia with a bupivacaine/morphine infusion (EPI-group, n=6) or a continuous i.v. infusion of morphine (MO-group, n=8). The concentration of glycerol, glucose and lactate in the abdominal and deltoid subcutaneous adipose tissue were measured using a microdialysis technique. RESULTS: The abdominal glycerol levels were equal in both groups. In the deltoid region of the EPI-group, glycerol concentrations started to increase on Day 2, and reached significantly higher levels on Day 3 compared with the MO-group. The glucose and lactate levels showed no differences between groups in the two regions. CONCLUSION: The uniform glycerol levels in abdominal subcutaneous adipose tissue in conjunction with the difference in glycerol levels in the deltoid area indicate that the local lipolysis is different in the two study groups. This might be explained by a regional metabolic influence of thoracic epidural analgesia, possibly via the sympathetic nervous system

Складові компоненти мовної особистості в контексті міжкультурної комунікації

Стаття присвячена аналізу складових компонентів мовної особистості в контексті міжкультурної комунікації, їх взаємодії та функціонуванню з точки зору прагматичної спрямованості мовленнєвого впливу. Детально розглядаються три рівні структури мовної особистості (структурно-мовний, лінгвокогнітивний ті мотиваційний) із визначенням специфіки їхніх складових компонентів.Статья посвящена анализу составляющих компонентов языковой личности в контексте межкультурной коммуникаций, их взаимодействию и функционированию с точки зрения прагматической направленности речевого воздействия. Детально рассматриваются три уровня структуры языковой личности (структурно-языковой, лингвокогнитивный и мотивационный) с последующим определением специфики их составляющих компонентов.The article is dedicated to the linguistic personality constituent components' analysis in terms of cross-cultural communication, their interaction and functioning with the speech influence pragmatic orientation taken into consideration. The three levels of the linguistic personality (that is, structural linguistic, lingo cognitive and motivation ones) are under analysis with the following their constituent components specificity determinatio

Perceptual Rivalry: Reflexes Reveal the Gradual Nature of Visual Awareness

Rivalry is a common tool to probe visual awareness: a constant physical stimulus evokes multiple, distinct perceptual interpretations (“percepts”) that alternate over time. Percepts are typically described as mutually exclusive, suggesting that a discrete (all-or-none) process underlies changes in visual awareness. Here we follow two strategies to address whether rivalry is an all-or-none process: first, we introduce two reflexes as objective measures of rivalry, pupil dilation and optokinetic nystagmus (OKN); second, we use a continuous input device (analog joystick) to allow observers a gradual subjective report. We find that the “reflexes” reflect the percept rather than the physical stimulus. Both reflexes show a gradual dependence on the time relative to perceptual transitions. Similarly, observers' joystick deflections, which are highly correlated with the reflex measures, indicate gradual transitions. Physically simulating wave-like transitions between percepts suggest piece-meal rivalry (i.e., different regions of space belonging to distinct percepts) as one possible explanation for the gradual transitions. Furthermore, the reflexes show that dominance durations depend on whether or not the percept is actively reported. In addition, reflexes respond to transitions with shorter latencies than the subjective report and show an abundance of short dominance durations. This failure to report fast changes in dominance may result from limited access of introspection to rivalry dynamics. In sum, reflexes reveal that rivalry is a gradual process, rivalry's dynamics is modulated by the required action (response mode), and that rapid transitions in perceptual dominance can slip away from awareness

The Extended Cleavage Specificity of Human Thrombin

Thrombin is one of the most extensively studied of all proteases. Its central role in the coagulation cascade as well as several other areas has been thoroughly documented. Despite this, its consensus cleavage site has never been determined in detail. Here we have determined its extended substrate recognition profile using phage-display technology. The consensus recognition sequence was identified as, P2-Pro, P1-Arg, P1′-Ser/Ala/Gly/Thr, P2′-not acidic and P3′-Arg. Our analysis also identifies an important role for a P3′-arginine in thrombin substrates lacking a P2-proline. In order to study kinetics of this cooperative or additive effect we developed a system for insertion of various pre-selected cleavable sequences in a linker region between two thioredoxin molecules. Using this system we show that mutations of P2-Pro and P3′-Arg lead to an approximate 20-fold and 14-fold reduction, respectively in the rate of cleavage. Mutating both Pro and Arg results in a drop in cleavage of 200–400 times, which highlights the importance of these two positions for maximal substrate cleavage. Interestingly, no natural substrates display the obtained consensus sequence but represent sequences that show only 1–30% of the optimal cleavage rate for thrombin. This clearly indicates that maximal cleavage, excluding the help of exosite interactions, is not always desired, which may instead cause problems with dysregulated coagulation. It is likely exosite cooperativity has a central role in determining the specificity and rate of cleavage of many of these in vivo substrates. Major effects on cleavage efficiency were also observed for residues as far away as 4 amino acids from the cleavage site. Insertion of an aspartic acid in position P4 resulted in a drop in cleavage by a factor of almost 20 times

GM-CSF drives dysregulated hematopoietic stem cell activity and pathogenic extramedullary myelopoiesis in experimental spondyloarthritis

Dysregulated hematopoiesis occurs in several chronic inflammatory diseases, but it remains unclear how hematopoietic stem cells (HSCs) in the bone marrow (BM) sense peripheral inflammation and contribute to tissue damage in arthritis. Here, we show the HSC gene expression program is biased toward myelopoiesis and differentiation skewed toward granulocyte-monocyte progenitors (GMP) during joint and intestinal inflammation in experimental spondyloarthritis (SpA). GM-CSF-receptor is increased on HSCs and multipotent progenitors, favoring a striking increase in myelopoiesis at the earliest hematopoietic stages. GMP accumulate in the BM in SpA and, unexpectedly, at extramedullary sites: in the inflamed joints and spleen. Furthermore, we show that GM-CSF promotes extramedullary myelopoiesis, tissue-toxic neutrophil accumulation in target organs, and GM-CSF prophylactic or therapeutic blockade substantially decreases SpA severity. Surprisingly, besides CD4+ T cells and innate lymphoid cells, mast cells are a source of GM-CSF in this model, and its pathogenic production is promoted by the alarmin IL-33