Properties of entangled photon pairs generated in one-dimensional nonlinear photonic-band-gap structures

We have developed a rigorous quantum model of spontaneous parametric down-conversion in a nonlinear 1D photonic-band-gap structure based upon expansion of the field into monochromatic plane waves. The model provides a two-photon amplitude of a created photon pair. The spectra of the signal and idler fields, their intensity profiles in the time domain, as well as the coincidence-count interference pattern in a Hong-Ou-Mandel interferometer are determined both for cw and pulsed pumping regimes in terms of the two-photon amplitude. A broad range of parameters characterizing the emitted down-converted fields can be used. As an example, a structure composed of 49 layers of GaN/AlN is analyzed as a suitable source of photon pairs having high efficiency.Comment: 14 pages, 23 figure

A reappraisal of the bladder cumulative method as a reliable technique for the measurement of glomerular filtration rate.

In order to quantify the decline in renal function, repeated measurements of GFR are necessary. The conventional procedure is cumbersome and time expending so that alternative clearance techniques are needed. We propose a simple isotopic technique for measuring GFR by 99mTc-DTPA and external counting of the bladder by gamma camera (bladder cumulative method). This consists in the measurement by external counting of the amount of labelled filtration marker accumulated in the bladder after intravenous bolus injection. In 36 adult patients with all degrees of renal impairment (serum creatinine 0.9-9.3 mg/dL) GFR was measured twice, once by the conventional method (continuous i.v. infusion of the filtration marker and urine collection by spontaneous voiding) and once by the bladder cumulative method. 99mTc DTPA was used in performing both methods. A satisfactory agreement was found between GFR measured by bladder cumulative method (BCM) and by conventional method (CM). The BCM averaged 60.0 +/- 36.7 mL/min and the CM +/- SD averaged 62.8 +/- 36.6 mL/mm. The ratio BCM/CM +/- SD was 0.95 +/- 0.14 (y = 0.94x + 1.14; r = 0.94). Considering the 17 patients with renal insufficiency (GFR60 mL/min) an even better agreement between the two methods was found. In these patients the BCM averaged 28.4 +/- 17.2 mL/min; the CM averaged 29.1 +/- 16.6 mL/min; and the ratio BCM/CM was 0.96 +/- 0.08 (y = 1.03x - 1.47; r = 0.99). The day-to-day variability of BCM, studied in another 11 patients, was lower than that of creatinine clearance (variation coefficient for duplicate measurements: 7.18 +/- 6.65 SD for BCM, 15.68 +/- 8.80 SD for CM, p0.01). The bladder cumulative method is a simple procedure for the accurate measurement of GFR, in particular in patients with renal insufficiency. It represents a reliable tool for estimating the decline in renal function

Neural processing of emotions in traumatized children treated with eye movement desensitization and reprocessing therapy: a hdEEG study

Eye Movement Desensitization and Reprocessing (EMDR) therapy has been proven efficacious in restoring affective regulation in Post-Traumatic Stress Disorder (PTSD) patients. However, its effectiveness on emotion processing in children with complex trauma has yet to be explored. High density Electroencephalography (hdEEG) was used to investigate the effects of EMDR on brain responses to adults\u27 emotions on children with histories of early maltreatment. Ten school-aged children were examined before (T0) and within one month after the conclusion of EMDR (T1). hdEEGs were recorded while children passively viewed angry, afraid, happy, and neutral faces. Clinical scales were administered at the same time. Correlation analyses were performed to detect brain regions whose activity was linked to children\u27s traumatic symptom-related and emotional-adaptive problem scores. In all four conditions, hdEEG showed similar significantly higher activity on the right medial prefrontal and fronto-temporal limbic regions at T0, shifting towards the left medial and superior temporal regions at T1. Moreover, significant correlations were found between clinical scales and the same regions whose activity significantly differed between pre- and post-treatment. These preliminary results demonstrate that, after EMDR, children suffering from complex trauma show increased activity in areas implicated in high-order cognitive processing when passively viewing pictures of emotional expressions. These changes are associated with the decrease of depressive and traumatic symptoms, and with the improvement of emotional-adaptive functioning over time

Hypertrichose diffuse révélant une hyperplasie congénitale des surrénales de forme non classique

BACKGROUND: Non-classical congenital adrenal hyperplasia (NC-CAH) is a recessive autosomal disease caused by a deficiency of adrenal steroidogenesis enzymes. It must be distinguished from classical CAH, either simple virilising or salt-wasting, diagnosed during the neonatal period and responsible for potentially lethal disorders of sexual differentiation. NC-CAH presents a simpler and less specific clinical picture. Herein, we present two cases comprising twin girls consulting for diffuse hypertrichosis. PATIENTS AND METHODS: Two 5-year-old twin girls were seen at our consultation for increased pilosity on all four limbs, but with no facial pilosity or synophrys, as well as comedones on the chin. Their height and weight and psychomotor development was normal, with no signs of precocious puberty and no clitoral hypertrophy. Levels of 17OH-P and SDHA were high, while FSH and LH were low and IGF1 and TSH were normal. Analysis of gene CYP21 associated with NC-CAH showed mutations p.V281L and IVS2-13A/C>G. Mutation p.V281L was present in the heterozygous state in the older sister and the father, together with moderate hyperpilosity but without hirsutism or acne. No mutations were found in the mother, indicating either de novo appearance of mutation IVS2-13A/C>G in the twins or germline mosaicism in the mother. DISCUSSION: We diagnosed NC-CAH as the cause of diffuse hypertrichosis in these twins. This disease is not rare, with a prevalence of 1/1000 to 1500 among peoples of European descent. It is often diagnosed late since routine neonatal screening is not performed. In some cases, NC-CAH remains asymptomatic. The appearance of pubic hair at around 5 to 7 years is the initial reason for consultation, particularly with a dermatologist. Hyperandrogenism varies, involving hirsutism, acne, fertility disorders and premature ageing of bone. Cortisol and aldosterone levels are generally normal. The risk of acute adrenal insufficiency is extremely low. Differential diagnosis concerns ovarian or adrenal tumors and polycystic ovary syndrome. 21-OH deficiency results in defective cortisol and aldosterone synthesis, and thus in raised ACTH, leading to increased adrenal androgen secretion. The early appearance of secondary sexual characteristics is associated with a gradual accumulation of 17-OHP. Depending on severity, hydrocortisone or anti-androgens may be given, or where treatment fails, aesthetic measures such as epilation or hair discolouration may be performed. CONCLUSION: In children presenting NC-CAH, the appearance of pubic hair and hirsutism often constitute the initial reasons for consultation, including with dermatologists. However, hypertrichosis may occur in isolation. It is important that these abnormalities be clearly known to enable early diagnosis and rapid initiation of simple and readily accessible treatment

Squeezed-light generation in a nonlinear planar waveguide with a periodic corrugation

Two-mode nonlinear interaction (second-harmonic and second-subharmonic generation) in a planar waveguide with a small periodic corrugation at the surface is studied. Scattering of the interacting fields on the corrugation leads to constructive interference that enhances the nonlinear process provided that all the interactions are phase matched. Conditions for the overall phase matching are found. Compared with a perfectly quasi-phase-matched waveguide, better values of squeezing as well as higher intensities are reached under these conditions. Procedure for finding optimum values of parameters for squeezed-light generation is described.Comment: 14 pages, 14 figure

No evidence for an association between the -871 T/C promoter polymorphism in the B-cell-activating factor gene and primary Sjögren's syndrome

Polyclonal B cell activation might be related to pathogenic over-expression of B-cell-activating factor (BAFF) in primary Sjögren's syndrome (pSS) and other autoimmune diseases. We therefore investigated whether BAFF over-expression in pSS could be a primary, genetically determined event that leads to the disease. The complete BAFF gene was sequenced in Caucasian pSS patients and control individuals. The only single nucleotide polymorphism frequently observed, namely -871 T/C in the promoter region, was then genotyped in 162 French patients with pSS and 90 French control individuals. No significant differences in allele (T allele frequency: 49.7% in patients with pSS versus 50% in controls; P = 0.94) and genotype frequencies of BAFF polymorphism were detected between pSS patients and control individuals. BAFF gene polymorphism was not associated with a specific pattern of antibody secretion either. T allele carriers had significantly increased BAFF protein serum levels (mean values of 8.6 and 5.7 ng/ml in patients with TT and TC genotypes, respectively, versus 3.3 ng/ml in patients with CC genotype; P = 0.01), although no correlation was observed between BAFF polymorphism and mRNA level. In conclusion, BAFF gene polymorphism is neither involved in genetic predisposition to pSS nor associated with a specific pattern of antibody production

Beneficial effects of δ-tocotrienol against oxidative stress in osteoblastic cells: studies on the mechanisms of action

Purpose Natural antioxidants are considered as promising compounds in the prevention/treatment of osteoporosis. We studied the ability of purified \u3b4-tocotrienol (\u3b4-TT) isolated from a commercial palm oil (Elaeis guineensis) fraction to protect osteoblast MC3T3-E1 and osteocyte MLO-Y4 cells against tert-butyl hydroperoxide (t-BHP)-induced oxidative damage and the mechanisms involved in its protective action in MC3T3-E1. Methods MC3T3-E1 and MLO-Y4 cells were treated with \u3b4-TT (1.25\u201320 \ub5g/ml for 2 h) followed by t-BHP at 250 \ub5M or 125 \ub5M for 3 h, respectively. MTT test was used to measure cell viability. Apoptotic cells were stained with Hoechst-33258 dye. Intracellular ROS levels were measured by dichlorofluorescein CM-DCFA. The OPT fluorimetric assay was used to detect the reduced glutathione to oxidized glutathione ratio (GSH/GSSG) contents. Results \u3b4-TT significantly prevented the effects of t-BHP on cell viability and apoptosis reaching a maximum protective activity at 10 and 5 \ub5g/ml in MC3T3-E1 and MLO-Y4 cells, respectively. This protective effect was due to a reduction of intracellular ROS levels and an increase in the defense systems shown by the increase in the GSH/GSSG. GSH loss induced by an inhibitor of GSH synthesis significantly reduced the \u3b4-TT-positive effect on ROS levels. \u3b4-TT prevention of oxidative damage was completely removed by combined treatment with the specific inhibitors of PI3K/AKT (LY294002) and Nrf2 (ML385). Conclusions The \u3b4-TT protective effect against oxidative damage in MC3T3-E1 cells is due to a reduction of intracellular ROS levels and an increase of the GSH/GSSG ratio, and involves an interaction between the PI3K/Akt\u2013Nrf2 signaling pathways

Risk factors for death and the 3-year survival of patients with systemic sclerosis: the French ItinérAIR-Sclérodermie study

Objectives. This longitudinal study investigated survival, risk factors and causes of death in the multicentre ItinérAIR-Sclérodermie cohort of patients with SSc without severe pulmonary fibrosis or severe left heart disease at baseline