CL as a tool for device characterisation: the case of laser diode degradation

Cathodoluminescence is a powerful technique for the characterization of semiconductors. Due to its high spatial resolution, it is emerging as a suitable method for the study of semiconductor devices. The reduced dimension of the devices and the multilayer structure of their active parts demand experimental means with high lateral resolution and probe depth tunability for characterising the different layers forming the device structure. Degradation is a crucial technological issue for high power devices. In particular, the failures of laser diodes are due to the formation of defects during the laser operation. Those defects can be imaged by cathodoluminescence; furthermore, its spectroscopic capabilities permit to go beyond the mere observation of the non-luminescent area morphology, allowing a better understanding of the physical mechanisms of degradation. We present herein an overview of the cathodoluminescence analysis of catastrophically degraded high power laser diodes, both single mode and multimode broad emitter lasers. The study of the defects responsible of the degradation is a step forward to establish models of degradation, necessary to improve the laser power and durability.

Identity of bryozoan species described by Jullien Calvet from the Bay of Biscay historically attributed to Smittia

During the late nineteenth and early twentieth centuries, a number of species of bryozoans were described in the genus Smittia Hincks, 1879 (a junior synonym of a dipteran genus). Jullien and/or Calvet named several species, mainly from the Bay of Biscay. Some of them have been re-examined in recent years and ascribed to Smittina Norman, 1903 and other genera. Five species, however, have remained unstudied. Here, type specimens of S. colletti, S. decipiens, S. fallax, S. gemmata, S. grimaldi and S. immersa-together with new specimens recently collected-are examined. The morphological study of all this material enabled the conclusion that only three species are involved. The synonymy of S. colletti with the senior species Smittina cervicornis is proposed; S. gemmata is transferred to the smittinid genus Raymondcia; and S. fallax, S. grimaldi and S. immersa, together with S. decipiens, are considered as junior subjective synonyms of Porella compressa.

Community-acquired Legionella Pneumonia in the intensive care unit: Impact on survival of combined antibiotic therapy

OBJECTIVES

To compare intensive care unit (ICU) mortality in patients with severe community-acquired pneumonia (SCAP) caused by Legionella pneumophila receiving combined therapy or monotherapy.

METHODS

A prospective multicenter study was made, including all patients with sporadic, community-acquired Legionnaires' disease (LD) admitted to the ICU. Admission data and information on the course of the disease were recorded. Antibiotic prescriptions were left to the discretion of the attending physician and were not standardized.

RESULTS

Twenty-five cases of SCAP due to L. pneumophila were included, and 7 patients (28%) out of 25 died after a median of 7 days of mechanical ventilation. Fifteen patients (60%) presented shock. Levofloxacin and clarithromycin were the antibiotics most commonly used in monotherapy, while the most frequent combination was rifampicin plus clarithromycin. Patients subjected to combination therapy presented a lower mortality rate versus patients subjected to monotherapy (odds ratio for death [OR] 0.15; 95%CI 0.02-1.04; p=0.08). In patients with shock, this association was stronger and proved statistically significant (OR for death 0.06; 95%CI 0.004-0.86; p=0.04).

CONCLUSIONS

Combined antibiotic therapy decreases mortality in patients with SCAP and shock caused by L. pneumophila.

Investigating a high ozone episode in a rural mountain site

A very high ozone episode with observed hourly values above 350 μg m(-3) occurred in July 2005 at the Lamas d'Olo air quality monitoring station, located in a mountainous area in the north of Portugal. Aiming to identify the origin and formation of this ozone-rich episode, a statistical analysis and a modelling approach were applied. A cross-spectrum analysis in the frequency domain and a synoptic analysis of the meteorological and air quality time series were performed. In order to go further in this analysis, a numerical modelling approach was applied. The results indicate that the transport of ozone and its precursors is the main responsible for the high ozone concentrations. Together with the local mountain breeze and subsidence conditions, the sea-breeze circulation transporting pollutants from the coastal urban and industrialized areas that reach the site during late afternoon turn out to be the driving forces for the ozone peaks.

First influenza season after the 2009 pandemic influenza: characteristics of intensive care unit admissions in adults and children in Vall d'Hebron Hospital

To assess potential differences in epidemiology and management of patients admitted with influenza infection in the intensive care unit (ICU) during the first post-pandemic influenza period. Observational prospective study comparing September 2009-January 2010 with September 2010-January 2011. Variables captured: demographics, co-morbidities, physiological parameters, outcomes and management. Analysis was performed using SPSS v. 13.0; significance was set at p 0.5. Data from 53 patients, 38 adults (age, median 41.5 years; interquartile range (IQR) 32.8-51.3) and 15 children (age, median 2 years, IQR 0.5-9) are presented. Vaccination rates were 0% and 4.3% during the first and second periods, respectively. Differences postpandemic were: 100% of episodes developed after December compared with 16.7% in the 2009 season. Younger children were affected (median age 0.8 years (IQR 0.3-4.8) vs 7 years (IQR 1.25-11.5), p 0.05) and influenza B caused 8.7% of ICU admissions. Influenza A (H1N1) 2009 and respiratory syncytial virus epidemics occurred simultaneously (42.8% of children) and bacterial co-infections doubled (from 10% to 21.7%); the prevalence of co-infections (viral or bacterial) increased from 10% to 39.1% (OR 5.8, 95% CI 1.3-24.8). Respiratory syndromes without chest X-ray opacities reflecting exacerbation of asthma or chronic obstructive pulmonary disease, bronchitis or bronchiolitis increased (from 6.9% to 39.1%, p<0.05) and pneumonia decreased (from 83.3% to 56.5%, p <0.05). Primary viral pneumonia predominated among ICU admissions. Postpandemic ICU influenza developed later, with some cases of influenza B, more frequent bacterial and viral co-infections and more patients with severe acute respiratory infection with normal chest X-ray. Increasing vaccination rates among risk-group individuals is warranted to prevent ICU admission and death.

EUS-guided mucosectomy for gastrointestinal cancer

INTRODUCTION

the only way of improving prognosis and survival in gastrointestinal cancer is early diagnosis, with intramucosal localization as confirmed by endoscopic ultrasonography (EUS) or 20-MHz miniprobes (MPs) (T1) being most appropriate. Endoscopic mucosal resection (EMR) has proven effective in the treatment of this sort of lesions.

PATIENTS AND METHOD

in a group (18 cases) with 15 cases of superficial gastrointestinal cancer and 3 cases of severe gastric dysplasia, 9 cases (3 esophageal, 4 gastric, 2 rectal) underwent a classic EMR following EUS or a 7.5- and 20-MHz miniprobe exploration.

RESULTS

ultrasonographic studies showed a T1 in all but one esophageal case (Tis), and in both gastric dysplasias, with no changed layer structure being demonstrated in the latter (T0). No complications arose with classic EMR, and all 9 patients are alive and free from local or metastatic recurrence, except for one esophageal case, which recurred distally to the esophageal lesion (metachronous).

CONCLUSIONS

echoendoscopically-assisted EMR is a safe, effective technique in the endoscopic management of superficial gastrointestinal (esophageal, gastric, colorectal) cancer. Recurrence most likely depends upon cancer multiplicity.

Pneumonia eosinofílica aguda com evolução para síndroma de dificuldade respiratória aguda: caso clínico

The Authors present a case of acute eosinophilic pneumonia (AEP) associated with severe acute respiratory distress syndrome in a previously healthy young adult, medicated with nitrofurantoin. AEP must be included in the differential diagnosis of community adquired pneumonia, as well as a cause of acute respiratory distress syndrome; its diagnosis is suggested by the presence of eosinophilic alveolitis in bronchoalveolar lavage fluid. The early diagnosis of AEP and corticosteroid therapy may be lifesaving.

[Drowning: tematic review and casuistic analysis in the Intensive Care Medicine Service of University Hospital of Coimbra (1989-2002)]

Drowning is a major cause of accidental deaths, especially in childrens. In this review (part one) the definition, epidemiology, pathophysiology and treatments (with an enphasis on the ressuscitation) are discussed. From 1989 to 2002 part two) we recorded the clinical course of the 19 patients vitims of submersion admited to our ICU. We conclued that the majority of patients are young (mean = 37,3 years), mortality is high (26%), but the complete recovery is possible (63%). The cardio-respiratory arrest or Glasgow Coma Scale < or = 5 were related with poor prognosis, only with 3 survivors (1 without sequels). Trauma associated lesions were observed only in one patient.

[Mucinous adenocarcinoma of the anal region. Study of 4 cases]

OBJECTIVE

We report 4 cases of a special anal tumor featuring a long history of inflammatory signs and fistulas in that area.

DESIGN

A retrospective study from the histologic diagnosis back to the first symptom and up to the last follow-up or death.

PATIENTS

We studied all patients with a histologic diagnosis of mucinous adenocarcinoma of the anus admitted to our hospital.

RESULTS

All of them showed a long history of anal inflammatory signs and/or fistula before diagnosis. In all cases, the tumors were mucinous adenocarcinomas with minimal cytologic atypia. Of the 4 patients, one is dead, and we have lost the follow-up of another one 13 months after surgery when he had no evidence of recurrence.

CONCLUSIONS

In every patient with a long-standing anal fistula or a recurrent anal abscess, a biopsy is mandatory to rule out an underlying low grade mucinous carcinoma and if it shows a low grade mucinous adenocarcinoma, the treatment of choice will be local resection if it is available. If not, an abdominal perineal resection showed be done without hesitation.