Extended cavity quantum cascade laser with cavity resonator integrated grating filter.

We report on an extended cavity quantum cascade laser based on a cavity resonator integrated grating filter (CRIGF) that acts as both cavity end-reflector and spectral selector. Stable, mode-hop free, single-mode emission around 2150 cm-1 is obtained over large injection current ranges (more than 50 mA) with a typical threshold around 290 mA. A digital frequency tuning over more than 65 cm-1 is obtained by changing the periodicity of the CRIGF ending the extended cavity.

Short communication: Evaluation of a foot dirtiness scoring system for dairy cows.

Lameness in dairy cattle is an important health and welfare concern directly affecting the economic benefits of farmers. Although foot dirtiness is a recognized risk factor for diseases inducing lameness, there is a lack of scoring systems that focus specifically on the foot. Therefore, the aim of this study was to evaluate the reliability of a 3-point dirtiness scoring system recently conceived for the assessment of the dirtiness present at the lower legs and claws of dairy cows. The scores of both the lateral and back views from 4 unfamiliar raters at 4 different times were used to evaluate interrater reliability (3 times) and intrarater scoring consistency (1 time). The findings of this investigation revealed that coefficients for interrater agreement (0.38, 0.62 and 0.63) and rating concordance (0.55, 0.75 and 0.74) of back-view scorings improved over time and were superior or similar to those obtained from lateral-view evaluations (coefficients for interrater agreement = 0.20, 0.35, and 0.69; coefficients for rating concordance = 0.48, 0.59, and 0.78). Additionally, the scoring consistency of the raters using the back-view grid was excellent (Cronbach's α = 0.93). The results suggest that the 3-point back-view dirtiness scoring grid may provide dairy consultants and farmers a reliable and easy tool for assessing cow foot dirtiness.

Mid-infrared cavity resonator integrated grating filters.

Cavity Resonator Grating Filters (CRIGFs) working in the Mid-Infrared are reported, with narrow-band resonant reflectivity peaks around 2200 cm-1 (4.6 µm). They are fabricated in the GaAs/AlGaAs material system that can potentially cover the whole [1-12] µm spectral range. TE-polarized peak reflectivity is 30% with a 4 cm-1 full width at half maximum.

Low incidence of cancer after venous thromboembolism: An update from the French OPTIMEV Cohort.

BACKGROUND: Recent studies have shown lower rates of cancer following venous thromboembolism (VTE) than previously described. OBJECTIVES: To reassess the risk of cancer in patients with clinical symptoms of VTE with or without confirmed VTE. PATIENTS: We used data from OPTIMEV, a French prospective multicenter observational study of patients presenting to hospital and community vascular medicine specialists with suspected VTE. Patients with confirmed VTE (1565) and matched controls without VTE (1847) were followed for 3 years (2006-2009). The main outcome was occurrence of cancer at 3 years, and death was a censoring event. RESULTS: A total of 5.0% [4.0-6.3] of patients with VTE and 3.8% [3.0-4.9] without VTE developed cancer during follow-up. The adjusted hazard ratio (HR) was 1.2 [0.9-1.8] for patients with confirmed VTE (P=0.22). The overall standardized incidence ratio (SIR) was 1.4 [1.1-1.6] for our population, VTE+ and VTE-, compared with the general population, statistically significant (P<0.05). CONCLUSIONS: We found a lower occurrence of cancer after VTE than previously described, with no significant difference between patients whether VTE was confirmed or not. Our results (low incidence and no difference between patients VTE+ or VTE-) provide no argument in favor of an extensive screening for cancer in case of VTE.

Impact of anatomical location of lower limb venous thrombus on the risk of subsequent cancer.

After a proximal deep-vein thrombosis (P-DVT), the risk of diagnosis of a previously unsuspected cancer is high. Isolated distal DVT (iD-DVT; i.e. infra-popliteal DVT without pulmonary embolism [PE]) and isolated superficial-vein thrombosis (iSVT; i.e. without concomitant DVT and PE) are at least as frequent as P-DVT but their association with subsequent cancer is uncertain. We exploited data from the OPTIMEV prospective, observational, multicentre study to i) compare the risk of subsequent cancer three years after a first objectively confirmed iSVT, iD-DVT and iP-DVT in patients without a prior history of cancer or of venous thromboembolism, ii) assess predictors of subsequent cancer in cases of iD-DVT. The overall cumulative rates of cancer among the 304 patients with iSVT, 536 patients with iD-DVT, and 327 patients with iP-DVT were similar (3.4% 95% confidence interval [1.8-6.2], 3.9% [2.5-5.9] and 3.9% [2.3-6.8], respectively), regardless of whether the index venous thromboembolic event was unprovoked or associated with a major transient risk factor. Neither anatomical (muscular vs deep-calf DVT) nor ultrasound scan characteristics (number of thrombosed veins, clot diameter under compression) seemed strongly associated with the risk of cancer in cases of iD-DVT. In patients managed in routine practice, all the different clinical expressions of lower limb venous thromboembolism are associated with a similar risk of subsequent cancer. From a clinical practice point of view, this suggests that cancer screening, without discussing the necessity, or not, of such screening, should not differ between a deep-proximal, deep-distal or superficial location of thrombosis.

[Temporary vena caval filters: report on cohort of 72 patients in Grenoble, France]. / Filtres cave temporaires: suivi d'une cohorte de 72 patients au CHU de Grenoble.

Patients with a contra-indication for anticoagulation can benefit from temporary vena caval filters for protection against pulmonary embolism or recurrence. The filter can be removed secondarily, once the contra-indication is overcome, enabling better long-term outcome by reducing the risk of thrombotic and mechanic complications inherent in these devices. However, it has been shown in several studies that effective withdrawal rates were low and could be improved by the establishment of protocols and registries. We report a retrospective study of withdrawal in 72 patients in whom an ALN® vena caval filter was implanted at the Grenoble University Hospital over a period of three years with an intention for secondary retrieval. Seventy percent of the indications were related to the coexistence of thrombotic and hemorrhagic conditions. Fifty-five percent of filters were removed, the remaining 45% shared involved patients who died before retrieval (11%), those lost to follow-up (4%), technical failure of retrieval (6%), withdrawal technically unfeasible (3%), retrieval refused by patients (6%) and medical indications for continuing filtration (15%). Despite an effective follow-up of these patients and 91% success rate of withdrawal, nearly one out of two filters remains in place. A long-term follow-up of these patients is needed to learn more about the outcome of these filters.

[Compression therapy and deep-vein thrombosis: a clinical practice survey]. / Compression veineuse et thrombose veineuse profonde. Enquête de pratique en médecine vasculaire.

BACKGROUND: Compression therapy constitutes the cornerstone of prevention of post-thrombotic syndrome in patients with deep-vein thrombosis (DVT). However, no consensus has been reached regarding the optimal timing for initiation, duration, and strength of compression therapy. OBJECTIVE: To document prescribing practices of compression therapy in case of DVT by French Vascular Medicine physicians. METHODS: E-mail survey sent in 2009 to all physicians members of the French Society of Vascular Medicine. RESULTS: Seven hundred and sixty-one vascular medicine physicians (56.6% private practice, 19.8% hospital-based and 23.6% both private practice and hospital-based physicians) responded. At diagnosis, 94.3% (n=707) systematically prescribed compression therapy. The initial compression consisted in elastic compression stockings (ECS) for 57.3% of patients (n=426) and in bandages for 42.7% (n=317). When physicians initially prescribed bandages, in 92.3% of cases they later switched to elastic compression stockings (ECS). Finally, 95.8% (n=712) of vascular medicine physicians reported prescribing ECS during DVT follow-up. The ECS ankle pressure gradient was 15-20 mmHg in 64.3% of cases and 20-36 mmHg in 35.5%. Most physicians (85.9%, n=631) modulated the duration of compression therapy according to the results of follow-up compression ultrasonographic explorations. Only a limited proportion of physicians took into account thrombus localization or its initial extention. CONCLUSION: In case of DVT, French vascular medicine physicians systematically prescribed compression therapy. However, the strength of compression was lower than recommended by international guidelines. Efficacy and benefits (potential better compliance) of this common practice should be assessed with a randomized controlled trial.

Bound states in optical absorption of semiconductor quantum wells containing a two-dimensional electron Gas

The dependence of the optical absorption spectrum of a semiconductor quantum well on two-dimensional electron concentration n(e) is studied using CdTe samples. The trion peak (X-) seen at low n(e) evolves smoothly into the Fermi edge singularity at high n(e). The exciton peak (X) moves off to high energy, weakens, and disappears. The X,X- splitting is linear in n(e) and closely equal to the Fermi energy plus the trion binding energy. For Cd0.998Mn0.002Te quantum wells in a magnetic field, the X,X- splitting reflects unequal Fermi energies for M = +/-1/2 electrons. The data are explained by Hawrylak's theory of the many-body optical response including spin effects.