11 W narrow linewidth laser source at 780nm for laser cooling and manipulation of Rubidium

We present a narrow linewidth continuous laser source with over 11 Watts of output power at 780nm, based on single-pass frequency doubling of an amplified 1560nm fibre laser with 36% efficiency. This source offers a combination of high power, simplicity, mode quality and stability. Without any active stabilization, the linewidth is measured to be below 10kHz. The fibre seed is tunable over 60GHz, which allows access to the D2 transitions in 87Rb and 85Rb, providing a viable high-power source for laser cooling as well as for large-momentum-transfer beamsplitters in atom interferometry. Sources of this type will pave the way for a new generation of high flux, high duty-cycle degenerate quantum gas experiments.Comment: 5 pages, 3 figure

Four-strand hamstring tendon autograft for ACL reconstruction in patients aged 50years or older

SummaryIntroductionReconstruction of the anterior cruciate ligament using a four-strand hamstring tendon autograft in symptomatic patients aged 50years or older is an accepted treatment option.HypotesisFour-strand hamstring tendon autograft although not universally utilized in patients who are at least 50years old is an efficient procedure to control knee instability.Material and methodsIn this retrospective, we analyzed the clinical outcomes of 18patients treated from September 1998 to September 2003. Criteria for inclusion were the following: age above 50years at surgery, chronic anterior laxity associated or not with meniscal damage; one or more episodes of knee instability and no prior ligament surgery on the involved knee. A same operative technique (arthroscopic single-bundle four-strand hamstring reconstruction, blind femoral tunnel, through anteromedial portals), a same fixation type (absorbable interference screws in femur and tibia) and a same rehabilitation protocol were used for all these knees. The IKDC 93scores were determined pre- and postoperatively combined with anteroposterior and lateral views, single leg stance, 30° flexion stance, and passive Lachman test (Telos) postoperatively.ResultsAt mean 30month-follow-up (range 12–59months), there were no graft failure and no loss of extension for any of these knees. Three patients complained of hypoesthesia in the medial saphenous nerve territory and one patient experienced posterior knee pain. All patients graded their knee as normal or nearly normal, all were satisfied or very satisfied with their operation. None of the patients reported instability. The Lachman-Trillat test was noted “firm end point” in 14knees and “delayed firm end point” in four. The pivot-shift test was negative in 16knees and mild positive in two. The mean residual differential laxity was 3.1mm (0 to +6mm) for the passive Lachman test. At last follow-up, the overall IKDC score was 7A, 7B, 3C, and 1 D. Patients with preserved meniscus (nine patients) reported a lesser degree of pain and a better residual laxity control compared with patients who had undergone a meniscectomy.ConclusionAge over 50years is not a contraindication to select a hamstring tendon autograft for ACL reconstruction. This surgery can restore knee stability but does not modify the pain pattern in patients, who had a medial meniscectomy prior to the ACL reconstruction.Level of evidence: level IV, therapeutic study

Overcoming Bottlenecks of Enzymatic Biofuel Cell Cathodes: Crude Fungal Culture Supernatant Can Help to Extend Lifetime and Reduce Cost

Enzymatic biofuel cells (BFCs) show great potential for the direct conversion of biochemically stored energy from renewable biomass resources into electricity. However, enzyme purification is time-consuming and expensive. Furthermore, the long-term use of enzymatic BFCs is hindered by enzyme degradation, which limits their lifetime to only a few weeks. We show, for the first time, that crude culture supernatant from enzyme-secreting micro-organisms (Trametes versicolor) can be used without further treatment to supply the enzyme laccase to the cathode of a mediatorless BFC. Polarization curves show that there is no significant difference in the cathode performance when using crude supernatant that contains laccase compared to purified laccase in culture medium or buffer solution. Furthermore, we demonstrate that the oxygen reduction activity of this enzymatic cathode can be sustained over a period of at least 120 days by periodic resupply of crude culture supernatant. This is more than five times longer than control cathodes without the resupply of culture supernatant. During the operation period of 120 days, no progressive loss of potential is observed, which suggests that significantly longer lifetimes than shown in this work may be possible. Our results demonstrate the possibility to establish simple, cost efficient, and mediatorless enzymatic BFC cathodes that do not require expensive enzyme purification procedures. Furthermore, they show the feasibility of an enzymatic BFC with an extended lifetime, in which self-replicating microorganisms provide the electrode with catalytically active enzymes in a continuous or periodic manner

Enzymatic Fuel Cells Solely Supplied with Unpurified Cellbiose Dehydrogenase and Laccase in Microorganism's Culture Supernatants

Enzymatic electrodes have great potential for catalysing the direct conversion of chemical compounds into electricity with the use of redox enzymes. However, expensive and time-consuming enzyme purification and the frequent need to add mediators are considered as drawbacks of enzymatic electrodes. We report a biofuel cell at pH 5, supplied with the unpurified enzymes laccase and cellobiose dehydrogenase (CDH) in crude culture supernatant, without the further addition of mediators. A maximum power output of 6.2±1.2 μW cm−2 was achieved by using supernatants containing laccase from Trametes versicolor (2.84 UmL−1) and CDH (0.90 UmL−1) from a recombinant yeast Yarrowia lipolytica YPC4. In comparison, the supply of purified enzymes (laccase: 2.40 UmL−1, CDH: 0.15 UmL−1) in a buffer solution yielded only about a twofold higher power density. Our results demonstrate the feasibility of using unpurified laccase and CDH in an enzymatic biofuel cell, which can simplify its construction and operation

Improving Focal Photostimulation of Cortical Neurons with Pre-derived Wavefront Correction

OBJECTIVES: Determinate whether hypoalbuminemia is a severity predictor of pre eclampsia in Belen Hospital. January – December 2013 MATERIAL AND METHODS: We conducted a retrospective, case-control study, evaluated 120 pregnant women, divided into 2 groups: cases (40 pregnant women diagnosed with severe preeclampsia who were measured the serum albumin) and controls (80 pregnant women with normal pregnancy who were measured the serum albumin). RESULTS: The mean serum albumin in patients with severe pre-eclampsia (cases) is 2,69 ± 0,35 gr/dl, while in women without pregnant pathology (controls) is 3,3 ± 0,28 gr/dl. Was also found that 75% of pregnant women with severe pre eclampsia (cases) has serum albumin < 3gr/dl. A significant difference was found between hypoalbuminemia and severe pre eclampsia (p < 0.05), Odd Ratio 12 and a confidence interval of 95%: 4.873 - 29.553 CONCLUSIONS:. Hypoalbuminemia is a severity predictor of pre eclampsia, finding OR 12 indicating that pregnant women with hypoalbuminemia have 12 times the risk of severe pre-eclampsia. The incidence of severe preeclampsia during the study period was 5,5%; mild pre eclampsia 1,6 % and severe pre eclampsia 3,9%TesisOBJETIVO: Determinar si la hipoalbuminemia es un predictor de severidad de pre eclampsia en el Hospital Belén Trujillo Enero-diciembre 2013. MATERIALES Y METODOS: Se realizó un estudio retrospectivo de casos y controles evaluándose 120 gestantes, distribuidas en 2 grupos: Casos (40 gestantes, con diagnostico de pre eclampsia severa a quienes se midió el nivel albumina sérica) y Controles (80 gestantes sin patología a quienes se midió nivel de albumina sérica. RESULTADOS: La media de albumina sérica en pacientes con pre eclampsia severa (casos) es de 2,69 ± 0,35 gr/dl, mientras que en gestantes sin patología fue de 3,3 ± 0,28 gr/dl. Además se encontró que el 75% de las gestantes con pre eclampsia severa (casos) presentó albumina sérica < 3gr/dl. Se encontró una diferencia significativa entre la hipoalbuminemia y pre eclampsia severa (p < 0.05), con Odd Ratio de 12 y un intervalo de confianza de 95%: 4.873 - 29.553 CONCLUSIONES: La hipoalbuminemia es un predictor de severidad de pre eclampsia, hallándose un OR de 12 lo cual indica que las gestantes con hipoalbuminemia tienen 12 veces más riesgo de presentar pre eclampsia severa. La tasa de incidencia de pre eclampsia en el Hospital Belen Trujillo durante el 2013 fue de 5,5%; siendo pre eclampsia leve 1,6 % y pre eclampsia severa 3,9%. Palabras claves: hipoalbuminemia, pre eclampsi

Sar1b mutant mice recapitulate gastrointestinal abnormalities associated with chylomicron retention disease

International audienceChylomicron retention disease (CRD) is an autosomal recessive disorder associated with biallelic Sar1b mutations leading to defects in intracellular chylomicron (CM) trafficking and secretion. To date, a direct cause-effect relationship between CRD and Sar1b mutation has not been established, but genetically modified animal models provide an opportunity to elucidate unrecognized aspects of these mutations. To examine the physiological role and molecular mechanisms of Sar1b function, we generated mice expressing either a targeted deletion or mutation of human Sar1b using the CRISPR-Cas9 system. We found that deletion or mutation of Sar1b in mice resulted in late-gestation lethality of homozygous embryos. Moreover, compared with WT mice, heterozygotes carrying a single disrupted Sar1b allele displayed lower plasma levels of triglycerides, total cholesterol, and HDL-cholesterol, along with reduced CM secretion following gastric lipid gavage. Similarly, decreased expression of apolipoprotein B and microsomal triglyceride transfer protein was observed in correlation with the accumulation of mucosal lipids. Inefficient fat absorption in heterozygotes was confirmed via an increase in fecal lipid excretion. Furthermore, genetically modified Sar1b affected intestinal lipid homeostasis as demonstrated by enhanced fatty acid β-oxidation and diminished lipogenesis through the modulation of transcription factors. This is the first reported mammalian animal model with human Sar1b genetic defects, which reproduces some of the characteristic CRD features and provides a direct cause-effect demonstration

Improving Focal Photostimulation of Cortical Neurons with Pre-derived Wavefront Correction

Recent progress in neuroscience to image and investigate brain function has been made possible by impressive developments in optogenetic and opto-molecular tools. Such research requires advances in optical techniques for the delivery of light through brain tissue with high spatial resolution. The tissue causes distortions to the wavefront of the incoming light which broadens the focus and consequently reduces the intensity and degrades the resolution. Such effects are detrimental in techniques requiring focal stimulation. Adaptive wavefront correction has been demonstrated to compensate for these distortions. However, iterative derivation of the corrective wavefront introduces time constraints that limit its applicability to probe living cells. Here, we demonstrate that we can pre-determine and generalize a small set of Zernike modes to correct for aberrations of the light propagating through specific brain regions. A priori identification of a corrective wavefront is a direct and fast technique that improves the quality of the focus without the need for iterative adaptive wavefront correction. We verify our technique by measuring the efficiency of two-photon photolysis of caged neurotransmitters along the dendrites of a whole-cell patched neuron. Our results show that encoding the selected Zernike modes on the excitation light can improve light propagation through brain slices of rats as observed by the neuron's evoked excitatory post-synaptic potential in response to localized focal uncaging at the spines of the neuron's dendrites