Electro-Optomechanical Modulation Instability in a Semiconductor Resonator.

In semiconductor nano-optomechanical resonators, several forms of light-matter interaction can enrich the canonical radiation pressure coupling of light and mechanical motion and give rise to new dynamical regimes. Here, we observe an electro-optomechanical modulation instability in a gallium arsenide disk resonator. The regime is evidenced by the concomitant formation of regular and dense combs in the radio-frequency and optical spectrums of the resonator associated with a permanent pulsatory dynamics of the mechanical motion and optical intensity. The mutual coupling between light, mechanical oscillations, carriers, and heat, notably through photothermal interactions, stabilizes an extended mechanical comb in the ultrahigh frequency range that can be controlled optically.

Short-term Effect and Acceptability of Manual Lymphatic Drainage for Paediatric Limb Lymphoedema: A Prospective Study.

Paediatric lymphoedema (LE) is a rare condition, for which there is little data available regarding treatments. The aim of this study was to assess the short-term effect and acceptability of a 30-min session of manual lymphatic drainage (MLD) in children with well-documented LE of the lower limbs. Fifteen children were included (8 males; median age 11 years). Comparison of the sum of circumference values for the whole limb before and after MLD revealed a slight, but significant, reduction (from a median of 289.8 to 285.5 cm, p = 0.024), but the limb volumes did not decrease significantly (from a median of 4,870.3 to 4,772.3 ml, p = 0.394). Dermal thickness, measured by high-resolution ultrasound, decreased from 1.44 to 1.40 mm (p < 0.001). All children reported improvement in well-being, and found MLD useful. In conclusion, MLD is well accepted by children, but has poor impact on LE swelling. However, it decreases cutaneous oedema by mobilizing the lymph fluid.

Comparison of several methods for pain management after video-assisted thoracic surgery for pneumothorax: an observational study.

BACKGROUND: There is no defined gold standard for pain management after video-assisted thoracic surgery (VATS) for pneumothorax. In addition to systemic analgesia, various loco-regional analgesic techniques have been proposed but remain poorly evaluated in this context. We aimed to assess the analgesic efficacy of several of these techniques for the management of postoperative pain. METHODS: We conducted a monocentric prospective observational cohort study from February 2017 to April 2018 in patients suffering from spontaneous pneumothorax and scheduled for VATS (n = 59). Patients received systemic analgesia (i) alone (n = 15); (ii) combined with a continuous paravertebral block (n = 9); (iii) combined with a continuous serratus plane block (n = 19); or (iv) single-shot serratus plane block (n = 16) as decided by the attending physician. Pain scores and analgesic-related side effects were prospectively collected by an independent observer during the first postoperative 72 h. The primary endpoint criterion was the cumulative oral morphine consumption at the end of the third postoperative day. Statistical analysis used univariate and multivariate step-by-step forward logistic regression models to determine risk factors associated with the main criteria. RESULTS: Mean pain scores and morphine consumption were not significantly different between the 4 groups. In the multivariate analysis, the use of a continuous serratus plane block through a catheter was the only technique associated with a reduced incidence of high-dose oral morphine consumption (OR 0.09-95%CI [0.01-0.79], p = 0.03). CONCLUSION: This study suggests that serratus plane block combined with continuous infusion through a catheter may have some benefits, although further studies are needed to confirm these results and determine the true place of the serratus plane block in pain management after VATS for pneumothorax.

Prediction models of methicillin sensitive Staphylococcus aureus ventilator associated pneumonia relapse in trauma and brain injury patients: A retrospective analysis.

PURPOSE: To describe the incidence and risk factors of methicillin sensitive Staphylococcus aureus ventilator associated pneumonia (MSSA-VAP) relapse in trauma and non-traumatic brain injury patients. MATERIALS AND METHODS: Retrospective observational monocentric cohort study of consecutive ICU patients who developed a first episode of MSSA-VAP after trauma and non-traumatic brain injury. MSSA-VAP relapse encompass MSSA-VAP treatment failure (persistence or recurrence of MSSA) or other pathogen - VAP. RESULTS: A total of 165 patients (71% of trauma and 29% of non-traumatic brain injury) with MSSA-VAP were included. MSSA-VAP relapse occurred in 54 (33%) patients, including 28 (17%) MSSA-VAP treatment failure and 46 (28%) other pathogen-VAP. Empirical first-line antibiotic therapy was appropriate in 96% of cases. In multivariate analysis, the presence of Streptococcus species (Odds ratio [OR] 7.37) and oropharyngeal flora (OR 3.64) as initial MSSA co-pathogen, suggested aspiration at the time of admission and independently predicted MSSA-VAP treatment failure. Initial Glasgow coma scale (OR 0.89), need for emergent surgery (OR 5.71) and the presence of an acute respiratory distress syndrome at the time of the first MSSA-VAP (3.99), independently predicted the onset of other pathogen - VAP. CONCLUSION: Early and simple factors may help to identify patients with high-risk of MSSA-VAP relapse.

Optomechanical resonating probe for very high frequency sensing of atomic forces.

Atomic force spectroscopy and microscopy are invaluable tools to characterize nanostructures and biological systems. State-of-the-art experiments use resonant driving of mechanical probes, whose frequency reaches MHz in the fastest commercial instruments where cantilevers are driven at nanometer amplitude. Stiffer probes oscillating at tens of picometers provide a better access to short-range interactions, yielding images of molecular bonds, but they are little amenable to high-speed operation. Next-generation investigations demand combining very high frequency (>100 MHz) with deep sub-nanometer oscillation amplitude, in order to access faster (below microsecond) phenomena with molecular resolution. Here we introduce a resonating optomechanical atomic force probe operated fully optically at a frequency of 117 MHz, two decades above cantilevers, with a Brownian motion amplitude four orders below. Based on Silicon-On-Insulator technology, the very high frequency probe demonstrates single-pixel sensing of contact and non-contact interactions with sub-picometer amplitude, breaking open current limitations for faster and finer force spectroscopy.

Postoperative serum levels of Endocan are associated with the duration of norepinephrine support after coronary artery bypass surgery.

BACKGROUND: Cardiopulmonary bypass (CPB) is associated with a systemic inflammatory response and an endothelial dysfunction, whose qualitative assessment appears to be a major issue. Endocan (ESM-1, endothelial cell specific molecule-1) is a protein preferentially expressed by the endothelium and previously associated with prognosis of septic shock or acute respiratory distress syndrome. In this pilot study, we investigated the kinetic of Endocan in planned coronary artery bypass grafting (CABG) surgery with CPB. PATIENTS AND METHODS: We conducted an observational, prospective, mono centre study. All adult patients with left systolic ejection fraction>50%, undergoing planned on-pump CABG, were screened for inclusion. A written informed consent was obtained. Measurements and main results Serum Endocan concentrations were respectively 2.4 [2.1-3.0] ng. mL-1, 10.4 [7.4-13.9] ng.mL-1, 5.7 [4.4-8.2] ng.mL-1, and 5.4 [4.1-7.5] ng.mL-1 at day 0, day 1, day 3 and day 5. Endocan concentrations increased at day 1, day 3, and day 5 in comparison with preoperative concentration (P<0.001). In the multivariate analysis, age (P=0.002), history of acute coronary syndrome (P=0.024) and the catecholamine-free days at day 28 (P=0.007) were associated to the increase of perioperative Endocan concentrations. CONCLUSION: Serum Endocan concentration increases after CABG surgery with CPB until day 1. The norepinephrine support increases the risk of Endocan release, suggesting a relationship between the kinetic of Endocan and the vasoplegic syndrome. At day 3, Endocan concentration decreases slowly but is not normalised at day 5. Further studies should investigate the prognostic value of the magnitude of postoperative Endocan concentration after cardiac surgery.

Noninvasive measurement of bone strontium.

The strontium content of bone has hitherto been impossible to measure noninvasively. A novel dual-photon absorptiometry (DPA) method was developed. 241Am (59.5 keV) and 133Ba (356 keV) were used as radiation sources. The linearity of the DPA method was studied in monkey bones ex vivo after treatment over 52 wk with strontium ranelate. The bone strontium expressed in terms of the percentage molar ratio SrHA/(SrHA + CaHA) x 100%, where HA denotes hydroxyapatite, was measured (1) by the DPA method and (2) by inductively coupled plasma-atomic emission spectrophotometry at the same distal site of the femur. The results correlated significantly: y = 0.33%Sr + 1.086x; r = 0.976; standard error of the estimate (SEE) = 0.57%Sr. In order to measure the accuracy error of Sr%, 30 normal volunteers were measured. Their mean values did not differ significantly from zero and the SD was 0.5%. The radiation dose was small, the equivalent whole-body dose to human subjects being 0.005 micro Sv. This novel DPA method is likely to be successful for bone strontium measurement in humans.

Fluoride and strontium accumulation in bone does not correlate with osteoid tissue in dialysis patients.

BACKGROUND: Osteomalacia is now a rare disease in dialysis patients in developed countries since the withdrawal of aluminium overload. The involvement of fluoride and strontium in the pathogenesis of the disease has been suggested. The aim of this study was to investigate a possible association between osteomalacia in dialysis patients and the fluoride or strontium contents of bone. METHODS: Of 271 bone biopsies from chronic haemodialysis patients referred to our centre, we studied the nine biopsies from patients with osteomalacia. They were compared with 23 biopsies from patients with hyperparathyroidism and 24 biopsies from patients with adynamic bone disease. Histomorphometric static and dynamic indices were measured. Bone fluoride and strontium contents were measured in biopsies from haemodialysis patients, and were compared with those of control patients. RESULTS: In the nine patients with osteomalacia, we found an absence of double labelled surfaces and increased osteoid thickness. Mild aluminium overload was observed in two of the nine patients. The bone strontium content of the entire dialysis population studied was not significantly different from control values (0.023+/-0.001 vs 0.019+/-0.002% mol/mol, P=0.15). However, bone strontium level was slightly but significantly increased in patients with osteomalacia (0.030+/-0.005%), compared with both controls (0.019+/-0.002%, P<0.05) and the other bone diseases (0.021+/-0.002%, P<0.05). Bone fluoride content was significantly higher in the entire dialysis population than in the controls (0.33+/-0.04 vs 0.13+/-0.018% (g/g ash weight), P=0.04). It was increased in osteomalacic patients compared with controls and with patients having hyperparathyroidism or adynamic bone disease. There was no correlation between formation indices (OV/BV, OS/BS, Ob.S/BS) and bone fluoride or strontium content. CONCLUSIONS: We found a prevalence of osteomalacia of 3.3% in our biopsy series for chronic dialysis patients. However, although bone strontium and fluoride contents were slightly increased, no causal relationship with these individual metals and osteomalacia could be firmly established in this small number of patients. The hypothesis of strontium- or fluoride-induced osteomalacia in renal patients merits further investigation.