Electrokinetic Behaviour and Interaction with Oxalic Acid of Different Hydrous Chromium(III) Oxides

Three samples of hydrous chromium(III) oxide have been prepared by different procedures, and their electrokinetic mobilities have been measured. In mineral media, isoelectric points were found to be 8.45 ±0.15. This value is shifted from the solution isoelectric point by –0.35 ±0.15, due to the contribution of solvation energy to the energy of ionic adsorption. On the basis of a simple model, it is suggested that the two successive surface acidity constants of hydrous chromium(III) oxide are pKS a1 = 7.17 and pKS a2 = 9.72. The influence of oxalic acidity on mobility may be described in terms of two successive adsorption equilibria, the first one conducive to the neutralization of positive protonic charge, and the second one originating a charge reversal. It is shown that the apparent affinity for this latter mode is lower in one of the samples, suggesting that surface complexation constants may in fact be sensitive to the history of hydrous chromium(III) oxide particles. The three samples show similar dissolution behaviour but the specific rates differ, in one case by two orders of magnitude. This difference is explained in terms of the influence of crosslinking on the reactivity

Electrokinetic Behaviour and Interaction with Oxalic Acid of Different Hydrous Chromium(III) Oxides

Three samples of hydrous chromium(III) oxide have been prepared by different procedures, and their electrokinetic mobilities have been measured. In mineral media, isoelectric points were found to be 8.45 ±0.15. This value is shifted from the solution isoelectric point by –0.35 ±0.15, due to the contribution of solvation energy to the energy of ionic adsorption. On the basis of a simple model, it is suggested that the two successive surface acidity constants of hydrous chromium(III) oxide are pKS a1 = 7.17 and pKS a2 = 9.72. The influence of oxalic acidity on mobility may be described in terms of two successive adsorption equilibria, the first one conducive to the neutralization of positive protonic charge, and the second one originating a charge reversal. It is shown that the apparent affinity for this latter mode is lower in one of the samples, suggesting that surface complexation constants may in fact be sensitive to the history of hydrous chromium(III) oxide particles. The three samples show similar dissolution behaviour but the specific rates differ, in one case by two orders of magnitude. This difference is explained in terms of the influence of crosslinking on the reactivity

Tratamiento quirúrgico de la luxación recidivante de rótula mediante técnica combinada de realineación proximal y distal

Los autores presentan su experiencia en el tratamiemto quirúrgico de la luxación recidivante de rótula, en una serie de 26 pacientes esqueléticamente maduros (27 rodillas), intervenidos tras fracaso de un periodo mínimo de seis meses de tratamiento conservador. El tiempo medio de seguimiento postoperatorio fue de 20 meses. La técnica quirúrgica realizada fue la realineación proximal según Insall, asociada a realineación distal tipo Emslie-Trillat. La patología intraarticular concomitante se resolvió mediante artroscopia previa en el mismo tiempo quirúrgico. Las complicaciones encontradas fueron, un caso de hematoma postoperatorio, dos cicatrices queloides, y cuatro casos de rigidez articular. Los resultados fueron excelentes en 21 pacientes. En cinco casos se objetivó clínica de sufrimiento patelar, postquirúrgico. Los buenos resultados obtenidos parecen tener relación con la seguridad que proporciona la técnica de realineación combinada proximal y distal unida a un programa meticuloso de rehabilitación precoz.We review our experience on the surgical treatment of the recurrent dislocation of the patella in a series of 26 mature patients (27 knees) operated on after failure of conservative treatment. The average period of postoperative follow-up was 20 mouths. As for surgical technique we performed proximal realignment according to Insall, associated to EmslieTrillat's distal realignment. Intraarticular concomitant pathology was treated by previous arthroscopy. Complications were found in one case with postoperative haematoma, two cases of queloid scar, and four cases of joint stiffness. Excellent results were achieved in 21 patients. In other five cases patellar complains persisted after surgery. The satisfactory results obtained seems to be due to the safety of the combined proximal-distal realignment procedure together with a meticulous programme for early rehabilitation

Roturas agudas de L.C.A. de la rodilla: refuerzo con cordón RD.S

Se presenta la técnica de reconstrucción en las roturas agudas del L.C.A. mediante reparación con cordón de P.D.S., así como los criterios seguidos por los autores ante las roturas agudas de dicho ligamento. Expone una casuística de 24 intervenciones, con un seguimiento de 1.5 años, sin haber encontrado complicaciones destacables y con un 75% de Muy Buenos Resultados y un 25% de Buenos Resultados.The technique used in the repair of acute rupture of the ACL with a band of PDS, together with the criteria followed by our department in such cases both acute are decribed. The describe 24 operations performed by them, with a follow-up of 1.5 years, with no major complications, 75% excellent results and 25% good results

Energy neutral operation of vibration energy-harvesting sensor networks for bridge applications

greatly benefit from the use of wireless sensor networks (WSNs), however energy harvesting for the operation of the network remains a challenge in this setting. While solar and wind power are possible and credible solutions to energy generation, the need for positioning sensor nodes in shaded and sheltered locations, e.g., under a bridge deck, is also often precluding their adoption in real-world deployments. In some scenarios vibration energy harvesting has been shown as an effective solution, instead. This paper presents a multihop vibration energy-harvesting WSN system for bridge applications. The system relies on an ultra-low power wireless sensor node, driven by a novel vibration based energy-harvesting technology. We use a receiver-initiated routing protocol to enable energy-efficient and reliable connectivity between nodes with different energy charging capabilities. By combining real vibration data with an experimentally validated model of the vibration energy harvester, a hardware model, and the COOJA simulator, we develop a framework to conduct realistic and repeatable experiments to evaluate the system before on-site deployment. Simulation results show that the system is able to maintain energy neutral operation, preserving energy with careful management of sleep and communication times. We also validate the system through a laboratory experiment on real hardware against real vibration data collected from a bridge. Besides providing general guidelines and considerations for the development of vibration energy-harvesting systems for bridge applications, this work highlights the limitations of the energy budget made available by traffic-induced vibrations, which clearly shrink the applicability of vibration energy-harvesting technology for WSNs to applications that do not generate an overwhelming amounts of data

Plastia sustitutiva del LCA con tendones de la pata de ganso cuadruples

Se han estudiado retrospectivamente 44 casos de pacientes a los que se les realizó por vía artrocóspica una plastia sustitutiva intraticular de reconstrucción del LCA, con tendones de Semitendinoso y Recto Interno antólogos, en 4 fascículos. La edad media de los pacientes fue de 25 años. Los resultados a corto plazo (2 años) obtenidos con KT-1000 a 30 Ib han sido excelente-bueno en 40 casos y aceptable en 4 casos. Cuatro casos referían sensación de inestabilidad. Los test de Lachman y Pívot-Shift fueron positivos en 3 casos. Con el test de Lysholm se obtuvo resultado excelente-bueno en 36 casos, regular en 6 y malo en 2 casos. Este tipo de plastia presenta una baja morbilidad de la zona dadora del injerto, comparativamente con la plastia HTH patelar antóloga, y sin alteración del aparato extensor.A retrospective study of 44 patients, who underwent an arthroscopically assisted ACL (anterior cruciata ligament) reconstruction with quadrupled semitendinosus/gracilis tendon autografts was performed. The mean age was 25 years. Short term outcomes of knee stability (2 years follow-up) with KT-1000 arthrometer at 30 pounds were excellent or good in 40 cases and acceptable in 4. Pain or joint swelling were not found. Instability complaints were found in 4 cases. Lachman and Pivot-shift were found positive in 3 cases. Lysholm questionnaire scores were excellent or good in 36 cases, fair in 6 cases and per in two cases, the donor site morbidity associated with hamstring harvest seems to be minimal compared with bonepatellar tendon-bone autograft without impairment of the extensor mechanism

Patient outcomes and characteristics in a contemporary quaternary Canadian cardiac intensive care unit

BACKGROUND: The modern-day cardiac intensive care unit (CICU) has evolved to care for patients with acute critical cardiac illness. We describe the current population of cardiac patients in a quaternary CICU. METHODS: Consecutive CICU patients admitted to the CICU at the Toronto General Hospital from 2014 to 2020 were studied. Patient demographics, admission diagnosis, critical care resources, complications, in-hospital mortality, and CICU and hospital length of stay were recorded. RESULTS: A total of 8865 consecutive admissions occurred, with a median age of 64.9 years. The most common primary cardiac diagnoses were acute decompensated heart failure (17.8%), non ST-elevation myocardial infarction (16.8%), ST-elevation myocardial infarction (15.5%), and arrhythmias (14.7%). Cardiogenic shock was seen in 13.2%, and out-of-hospital cardiac arrest in 4.1%. A noncardiovascular admission diagnosis accounted for 13.9% of the cases. Over the period studied, rates of admission were higher for cardiogenic shock (P < 0.001 for trend), with a higher use of critical care resources. Additionally, rates of admission were higher in female patients and those who had chronic kidney disease and diabetes. The in-hospital mortality rate of all CICU admissions was 13.2%, and it was highest in those with noncardiac conditions, compared to the rate in those with cardiac diagnoses (29.4% vs 10.6%, P < 0.001). CONCLUSIONS: Given the trends of higher acuity of patients with cardiac critical illness, with higher use of critical care resources, education streams for critical care within cardiology, and alternative pathways of care for patients who have lower-acuity cardiac disease remain imperative to manage this evolving population

Prediction, prevention, and management of right ventricular failure after left ventricular assist device implantation: A comprehensive review

Left ventricular assist devices (LVADs) are increasingly common across the heart failure population. Right ventricular failure (RVF) is a feared complication that can occur in the early post-operative phase or during the outpatient follow-up. Multiple tools are available to the clinician to carefully estimate the individual risk of developing RVF after LVAD implantation. This review will provide a comprehensive overview of available tools for RVF prognostication, including patient-specific and right ventricle (RV)-specific echocardiographic and hemodynamic parameters, to provide guidance in patient selection during LVAD candidacy. We also offer a multidisciplinary approach to the management of early RVF, including indications and management of right ventricular assist devices in this setting to provide tools that help managing the failing RV

Razvoj i validacija spektrofotometrijskih metoda za određivanje ceftazidima u farmaceutskim doziranim pripravcima

Two spectrophotometric methods for the determination of ceftazidime (CFZM) in either pure form or in its pharmaceutical formulations are described. The first method is based on the reaction of 3-methylbenzothiazolin-2-one hydrazone (MBTH) with ceftazidime in the presence of ferric chloride in acidic medium. The resulting blue complex absorbs at λmax 628 nm. The second method describes the reaction between the diazotized drug and N-(1-naphthyl)ethylenediamine dihydrochloride (NEDA) to yield a purple colored product with λmax at 567 nm. The reaction conditions were optimized to obtain maximum color intensity. The absorbance was found to increase linearly with increasing the concentration of CFZM; the systems obeyed the Beer’s law in the range 210 and 1050 µg mL1 for MBTH and NEDA methods, respectively. LOD, LOQ and correlation coefficient values were 0.15, 0.79 and 0.50, 2.61. No interference was observed from common excipients present in pharmaceutical formulations. The proposed methods are simple, sensitive, accurate and suitable for quality control applications.Razvijene su dvije spektrofotometrijske metode za određivanje ceftazidima (CFZM), čistog ili u farmaceutskim pripravcima. Prva metoda se temelji na reakciji 3-metilbenzotiazolin-2-on hidrazona (MBTH) sa ceftazidimom u prisutnosti željezovog(III) klorida u kiselom mediju. Nastaje plavi kompleks s maksimumom apsorpcije pri λmax 628 nm. Druga metoda se temelji na reakciji između diazotiranog lijeka i N-(1-naftil)etilendiamin dihidroklorida (NEDA), pri čemu nastaje ljubičasti produkt s λmax pri 567 nm. Reakcijski uvjeti su optimirani da se dobije maksimalni intenzitet boje. Apsorbancija raste linearno s porašću koncentracije CFZM; sustavi slijede Beerov zakon u koncentracijskom području 210 za MBTH metodu i 1050 µg mL1 za NEDA metodu. LOD i LOQ te vrijednosti korelacijskog koeficijenta su 0,15, 0,79 i 0,50, 2,61. Uobičajene pomoćne tvari ne smetaju određivanju ceftazidima. Predložene metode su jednostavne, osjetljive, točne i pogodne za primjenu u kontroli kvalitete

Advances in the Development of Mid-Infrared Integrated Devices for Interferometric Arrays

This article reports the advances on the development of mid-infrared integrated optics for stellar interferometry. The devices are fabricated by laser writing techniques on chalcogenide glasses. Laboratory characterizaton is reported and analyzed.Comment: 12 pages, 9 figures, SPIE Astronomical Telescopes and Instrumentatio