A versatile micro-scale silicon sensor/actuator with low power consumption

We designed a CMOS compatible hot-surface silicon device operating at a power down to sub-µW. It has a pillarshaped structure with a nano-size (10-100 nm) conductive link between the electrodes separated by a SiO2 layer. The device is capable of maintaining a µm-size hot-surface area of several hundred degrees centigrade due to non-radiative recombination of carriers in a thin (13 nm) poly silicon surface layer. Such a device can be used as a light source, a heat source, as well as a sensitive detector of light and heat. As a direct application, we demonstrate the feasibility to perform as an adsorption-desorption sensor, and as a unit for activating chemisorption/decomposition (i.e. micro-reactor)

A pillar-shaped antifuse-based silicon chemical sensor and actuator

We designed a silicon-processing compatible, simple, and cheap device operating at a power down to sub- W. It has a pillar-shaped structure with a nanoscopic (10–100 nm in size) conductive link (the so-called antifuse) created between two electrodes separated by a SiO2 layer. The device exhibits a diode-like behavior due to the depletion effects in the mono-silicon pillar. The device is capable of maintaining a microscopic hot-surface area of several hundreds degrees centigrade. The size of the hot area and its temperature can be manipulated by the sign of the applied bias.\ud Two different heat-generation mechanisms (i.e., dissipation at a resistor and a non-radiative recombination of carriers) are proposed and modelled. Such a device can be used as a heat source, as a light source, and as a sensitive detector of light and heat. In this paper, we describe thermo-electrical properties of the fabricated devices and demonstrate their feasibility to perform as gas-, adsorption-, desorption sensors, and as units for activating chemisorption/decomposition of gaseous precursors, i.e., micro-reactors.\u

Low-power micro-scale CMOS-compatible silicon sensor on a suspended membrane.

In this paper we describe a new, simple and cheap silicon device operating at high temperature at a very low power of a few mW. The essential part of the device is a nano-size conductive link 10-100 nm in size (the so-called antifuse) formed in between two poly-silicon electrodes separated by a thin SiO2 layer. The device can be utilized in chemical sensors or chemical micro-reactors requiring high temperature and very low power consumption e.g. in portable, battery operated systems. As a direct application, we mention a gas sensor (i.e. Pellistor) for hydrocarbons (butane, methane, propane, etc.) based on temperature changes due to the catalytic combustion of hydrocarbons. The power consumed by our device is at about 2% of the power consumed by conventional Pellistors

Persistent median artery in the carpal tunnel: anatomy, embryology, clinical significance, and review of the literature

The median artery usually regresses after the eighth week of intrauterine life, but in some cases it persists into adulthood. The persistent median artery (PMA) passes through the carpal tunnel of the wrist, accompanying the median nerve. During anatomical dissection in our department, we found two unilateral cases of PMA originating from the ulnar artery. In both cases the PMA passed through the carpal tunnel, reached the palm, and anastomosed with the ulnar artery, forming a medio-ulnar type of superficial palmar arch. In addition, in both cases we observed a high division of the median nerve before entering the carpal tunnel. Such an artery may result in several complications such as carpal tunnel syndrome, pronator syndrome, or compression of the anterior interosseous nerve. Therefore, the presence of a PMA should be taken into consideration in clinical practice. This study presents two cases of PMA along with an embryological explanation, analysis of its clinical significance, and a review of the literature. The review of the literature includes cases observed during surgical procedures or anatomical dissections. Cases observed by means of imaging techniques were not included in the study

Analytical expression for the quantum dot contribution to the quasistatic capacitance for conduction band characterization

This paper demonstrates an analytical expression for the quasistatic capacitance of a quantum dot layer embedded in a junction, where the reverse bias is used to discharge the initially occupied energy levels. This analysis can be used to determine the position and the Gaussian homogeneous broadening of the energy levels in the conduction band, and is applied for an InGaAs/GaAs quantum dot structure grown by metal organic chemical vapor deposition. It is shown that the Gaussian broadening of the conduction band levels is significantly larger than the broadening of the interband photoluminescence (PL) transitions involving both conduction and hole states. The analysis also reveals a contribution from the wetting layer both in PL and modeled C-V profiles which is much stronger than in typical molecular beam epitaxy grown dots. The presence of a built-in local field oriented from the apex of the dot toward its base, contrary to the direction expected for a strained dot with uniform composition (negative dipole), is also derived from fitting of the C-V experimental data

The laparoscopic treatment of perforated duodenal ulcer in Romania – a multicentric study

Clinica Chirurgie 2, Timișoara, România, Clinica Chirurgie, Spitalul de Urgență, București, Al XI-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova și cea de-a XXXIII-a Reuniune a Chirurgilor din Moldova „Iacomi-Răzeșu” 27-30 septembrie 2011Aims. This retrospective study was evaluated the results of laparoscopic treatment of the perforated duodenal ulcer (PDU) in 6 Romanian centres with an important experience in laparoscopic surgery.Methods. Between 2000 and 2010, 221 patients (38 females and 183 men) aged from 18 to 78 years, were operated laparoscopicaly for PDU, by using 3 (66.0%), 4 (27%) or 5 (7.0%) trocars. Forty six (20.8%) of them had a weak, 143(64.7%) an important and 32(14.5%) a grave peritonitis. Procedures performed were: simple suture 84(38.1%) patients, suture with epiplonoplasty 135(61.1%) patients, only epiplonoplasty 1(0.4%) patients, excision with suture 1(0.4%) patients. All patients had abundant peritoneal cavity washing and tub drainage (1-3 tubs).Results. The interventions lasted between 30 and 120 min, with an average of 63 min. No mortality was reported. Postoperative oral nutrition began after 24 hours for 114(51.6%) patients and after intestinal transit has restarted for 107(48.4%) patients. The intestinal transit has restarted after 1-6 days (average 3.5 days), depending of the gravity of peritonitis. Complications were: parietal infections 3 (1.3%), duodenal fistula 1 (0.4%), abdominal abcesses 1(0.4%), digestive haemorrhage 1(0.4%) and duodenal stenosis 1 (0.4%). Hospitalization lasted between 2 and 13 days (average 5.5 days). In comparison with open techniques, patients had the same intravenous perfusions, less pain, less antibiotics, less dressings, less complications during postoperative evolution. Conclusion. Laparoscopic treatment of PDU is safe even in case of severe peritonitis, with faster patient’s recovery. with less complications and with less postoperative medical care than open procedures. Aims. This retrospective study was evaluated the results of laparoscopic treatment of the perforated duodenal ulcer (PDU) in 6 Romanian centres with an important experience in laparoscopic surgery.Methods. Between 2000 and 2010, 221 patients (38 females and 183 men) aged from 18 to 78 years, were operated laparoscopicaly for PDU, by using 3 (66.0%), 4 (27%) or 5 (7.0%) trocars. Forty six (20.8%) of them had a weak, 143(64.7%) an important and 32(14.5%) a grave peritonitis. Procedures performed were: simple suture 84(38.1%) patients, suture with epiplonoplasty 135(61.1%) patients, only epiplonoplasty 1(0.4%) patients, excision with suture 1(0.4%) patients. All patients had abundant peritoneal cavity washing and tub drainage (1-3 tubs). Results. The interventions lasted between 30 and 120 min, with an average of 63 min. No mortality was reported. Postoperative oral nutrition began after 24 hours for 114(51.6%) patients and after intestinal transit has restarted for 107(48.4%) patients. The intestinal transit has restarted after 1-6 days (average 3.5 days), depending of the gravity of peritonitis. Complications were: parietal infections 3 (1.3%), duodenal fistula 1 (0.4%), abdominal abcesses 1(0.4%), digestive haemorrhage 1(0.4%) and duodenal stenosis 1 (0.4%). Hospitalization lasted between 2 and 13 days (average 5.5 days). In comparison with open techniques, patients had the same intravenous perfusions, less pain, less antibiotics, less dressings, less complications during postoperative evolution. Conclusion. Laparoscopic treatment of PDU is safe even in case of severe peritonitis, with faster patient’s recovery. with less complications and with less postoperative medical care than open procedures

Low-loss, low-confinement GaAs-AlGaAs DQW laser diode with optical trap layer for high-power operation

A low-confinement asymmetric GaAs-AlGaAs double-quantum-well molecular-beam-epitaxy grown laser diode structure with optical trap layer is characterized, The value of the internal absorption coefficient is as low as 1.4 cm-1, while keeping the series resistance at values comparable cm with symmetrical quantum-well gradient index structures in the same material system. Uncoated devices show COD values of 35 mW/µm. If coated, this should scale to about 90 mW/µm. The threshold current density is about 1000 A/cm2 for 2-mm-long devices and a considerable part of it is probably due to recombination in the optical trap layer. Fundamental mode operation is limited to 120-180 mW for 6.5-µm-wide ridge waveguide uncoated devices and to 200-300 mW for 13.5-µm-wide ones, because of thermal waveguiding effects. These values are measured under pulsed conditions, 10 µs/l m

Introducing Semi-Interpenetrating Networks of Chitosan and Ammonium-Quaternary Polymers for the Effective Removal of Waterborne Pathogens from Wastewaters

The present work aims to study the influence of ammonium-quaternary monomers and chitosan, obtained from different sources, upon the effect of semi-interpenetrating polymer network (semi-IPN) hydrogels upon the removal of waterborne pathogens and bacteria from wastewater. To this end, the study was focused on using vinyl benzyl trimethylammonium chloride (VBTAC), a water-soluble monomer with known antibacterial properties, and mineral-enriched chitosan extracted from shrimp shells, to prepare the semi-IPNs. By using chitosan, which still contains the native minerals (mainly calcium carbonate), the study intends to justify that the stability and efficiency of the semi-IPN bactericidal devices can be modified and better improved. The new semi-IPNs were characterized for composition, thermal stability and morphology using well-known methods. Swelling degree (SD%) and the bactericidal effect assessed using molecular methods revealed that hydrogels made of chitosan derived from shrimp shell demonstrated the most competitive and promising potential for wastewater (WW) treatment.Introducing Semi-Interpenetrating Networks of Chitosan and Ammonium-Quaternary Polymers for the Effective Removal of Waterborne Pathogens from WastewaterspublishedVersio