A simple-architecture fibered transmission system for dissemination of high stability 100 MHz signals.

We report on the development of a simple-architecture fiber-based frequency distribution system used to transfer high frequency stability 100 MHz signals. This work is focused on the emitter and the receiver performances that allow the transmission of the radio-frequency signal over an optical fiber. The system exhibits a residual fractional frequency stability of 1 × 10-14 at 1 s integration time and in the low 10-16 range after 100 s. These performances are suitable to transfer the signal of frequency references such as those of a state-of-the-art hydrogen maser without any phase noise compensation scheme. As an application, we demonstrate the dissemination of such a signal through a 100 m long optical fiber without any degradation. The proposed setup could be easily extended for operating frequencies in the 10 MHz-1 GHz range.

The effect of formalizing enhanced recovery after esophagectomy with a protocol.

Enhanced recovery after surgery (ERAS) pathways aim to accelerate functional return and discharge from hospital. They have proven effective in many forms of surgery, most notably colorectal. However, experience in esophagectomy has been limited. A recent study reported significant reductions in pulmonary complications, mortality, and length of stay following the introduction of an ERAS protocol alone, without the introduction of any clinical changes. We instituted a similar change 16 months ago, introducing a protocol to provide a formal framework, for our existing postoperative care. This retrospective analysis compared outcome following esophagectomy for the 16 months before and 20 months after this change. Data were collected from prospectively maintained secure web-based multidisciplinary databases. Complication severity was classified using the Clavien-Dindo scale. Operative mortality was defined as death within 30 days of surgery, or at any point during the same hospital admission. Lower respiratory tract infection was defined as clinical evidence of infection, with or without radiological signs. Respiratory complications included lower respiratory tract infection, pleural effusion (irrespective of drainage), pulmonary collapse, and pneumothorax. Statistical analysis was performed using SPSS v21. One hundred thirty-two patients underwent esophagectomy (55 protocol group; 77 before). All were performed open. There were no differences between the two groups in terms of age, gender, operation, use of neoadjuvant therapy, cell type, stage, tumor site, or American Society of Anesthesiologists grade. Median length of stay was 14.0 days (protocol) compared with 12.0 before (interquartile range 9-19 and 9.5-15.5, respectively; P = 0.073, Mann-Whitney U-test). Readmission within 30 days of discharge occurred in five (9.26%) and six (8.19%; P = 1.000, Fisher's exact test). There were four in-hospital deaths (3.03%): one (1.82%) and three (3.90%), respectively (P = 0.641). There were no differences in the severity of complications (P = non-significant; Pearson's chi-squared). There were no differences in the type of complications occurring in either group. The protocol was completed successfully by 26 (47.3%). No baseline factors were predictive of this. In contrast to previous studies, we did not demonstrate any improvement in outcome by formalizing our existing pathway using a written protocol. Consequently, improvements in short-term outcome from esophagectomy within ERAS would seem to be primarily due to improvements in components of perioperative care. Consequently, we would recommend that centers introducing new (or reviewing existing) ERAS pathways for esophagectomy focus on optimizing clinical aspects of such standardized pathways.

Laser locking to the 199Hg 1S0-3P0 clock transition with 5.4 × 10(-15)/✓τ fractional frequency instability.

With 199Hg atoms confined in an optical lattice trap in the Lamb-Dicke regime, we obtain a spectral line at 265.6 nm for which the FWHM is ~15 Hz. Here we lock an ultrastable laser to this ultranarrow 1S0-3P0 clock transition and achieve a fractional frequency instability of 5.4×10(-15)/✓τ for τ ≤ 400 s. The highly stable laser light used for the atom probing is derived from a 1062.6 nm fiber laser locked to an ultrastable optical cavity that exhibits a mean drift rate of -6.0×10(-17) s(-1) (-16.9 mHz s(-1) at 282 THz) over a six month period. A comparison between two such lasers locked to independent optical cavities shows a flicker noise limited fractional frequency instability of 4×10(-16) per cavity.

Lattice-induced frequency shifts in Sr optical lattice clocks at the 10(-17) level.

We present a comprehensive study of the frequency shifts associated with the lattice potential in a Sr lattice clock by comparing two such clocks with a frequency stability reaching 5×10(-17) after a 1 h integration time. We put the first experimental upper bound on the multipolar M1 and E2 interactions, significantly smaller than the recently predicted theoretical upper limit, and give a 30-fold improved upper limit on the effect of hyperpolarizability. Finally, we report on the first observation of the vector and tensor shifts in a Sr lattice clock. Combining these measurements, we show that all known lattice related perturbations will not affect the clock accuracy down to the 10(-17) level, even for lattices as deep as 150 recoil energies.

Ultra-low-noise microwave extraction from fiber-based optical frequency comb.

In this Letter we report on an all-optical-fiber approach to the generation of ultra-low-noise microwave signals. We make use of two erbium fiber mode-locked lasers phase locked to a common ultrastable laser source to generate an 11.55 GHz signal with an unprecedented relative phase noise of -111 dBc/Hz at 1 Hz from the carrier. The residual frequency instability of the microwave signals derived from the two optical frequency combs is below 2.3x10(-16) at 1 s and about 4x10(-19) at 6.5x10(4) s (in 5 Hz bandwidth, three days of continuous operation).

Neurosciences intensive care medicine in initial neurosurgical training.

The authors describe a novel 4-month clinical placement in neurosciences intensive care medicine (NICM) undertaken in the first specialty registrar (ST1) year of neurosurgical training as part of a clinical neurosciences themed training year. Neurosurgery is unique among British surgical specialties in having pioneered themed early years in run-through training to replace basic surgical training in general surgical specialties as part of Modernising Medical Careers. After describing events leading to the new neurosurgical training, the knowledge, skills and attitudes acquired in NICM are highlighted alongside discussion of logistic aspects and future directions from an inaugural experience.

Chemosterilants as control agents of Ceratitis capitata (Diptera: Tephritidae) in field trials.

Lufenuron is a chitin synthesis inhibitor, which is able to impede Mediterranean fruit fly, Ceratitis capitata (Wiedemann), reproduction. In laboratory trials, following ingestion of lufenuron, the eggs laid by female Ceratitis capitata were prevented from hatching. In field trials in Valencia, Spain, lufenuron showed its effectiveness by reducing C. capitata wild populations and its continuous application to several generations of fruit fly resulted in increased pest control. This field trial was conducted in an isolated valley some 80 ha in size, over a continuous four-year period. In order to maintain the sterilizing effect in the field throughout the whole year, a new lufenuron bait gel was developed. This bait gel was introduced in to delta traps suspended in trees at a density of 24 traps ha-1, and these traps were replaced once a year during the field trial. Monitoring of the adult C. capitata population was conducted to assess the effects of the chemosterilant treatment. In the first year of treatment with sterilizing traps, a reduction of the C. capitata population was observed, indicating that the traps reduce the population right from the first generation. In the second, third and fourth years, a continuous and progressive reduction of the adult Mediterranean fruit fly population was observed. Therefore, the successive application of chemosterilization treatment has a cumulative effect on reducing the fly population year after year. Aerial treatment using malathion does not produce this cumulative effect, and consequently every year it is necessary to start again with the same number of flies as the year before. The possibility of using the chemosterilant method alone or combined with the sterile insect technique is discussed.

Nitric oxide synthase is downregulated, while haem oxygenase is increased, in patients with septic shock.

BACKGROUND: The vasodilatation characteristic of human septic shock is conventionally attributed to increased nitric oxide production, primarily by extrapolation of animal and human in vitro studies. There are no conclusive studies of human disease, and the cellular source of nitric oxide in human sepsis is not known. Haem oxygenase is upregulated by oxidative stress, but little is known about haem oxygenase expression in human sepsis. Haem oxygenase may modulate nitric oxide production, and may also have a direct effect on vascular tone. METHODS: Mesenteric arterial smooth muscle (ASM) (obtained during laparotomy) and peripheral blood mononuclear cells (PBMCs) were obtained from patients with early septic shock and from control patients. mRNA levels were determined by real-time RT-PCR. RESULTS: mRNA for inducible and endothelial nitric oxide synthase was reduced in both ASM and PBMCs from septic patients. In contrast, inducible haem oxygenase mRNA was increased in sepsis in both cell types. CONCLUSIONS: These results suggest that, rather than being induced, the enzymes which produce nitric oxide are reduced at this time point in human septic shock. Thus many of the in vitro models of sepsis studied to date may not fully replicate human disease. The increase in haem oxygenase expression confirms that these cells have been subjected to oxidative stress in sepsis. The activity of induced haem oxygenase may limit nitric oxide production, while possibly causing vasodilation through production of carbon monoxide.

TNF and TNFR polymorphisms in severe sepsis and septic shock: a prospective multicentre study.

Tumour necrosis factor (TNF) is an important pro-inflammatory cytokine produced in sepsis. Studies examining the association of individual TNF single nucleotide polymorphisms with sepsis have produced conflicting results. This study investigated whether common polymorphisms of the TNF locus and the two receptor genes, TNFRSF1A and TNFRSF1B, influence circulating levels of encoded proteins, and whether individual polymorphisms or extended haplotypes of these genes are associated with susceptibility, severity of illness or outcome in adult patients with severe sepsis or septic shock. A total of 213 Caucasian patients were recruited from eight intensive care units (ICU) in the UK and Australia. Plasma levels of TNF (P = 0.02), sTNFRSF1A (P = 0.005) and sTNFRSF1B (P = 0.01) were significantly higher in those who died on ICU compared to those who survived. There was a positive correlation between increasing soluble receptor levels and organ dysfunction (increasing SOFA score) (sTNFRSF1A R = 0.51, P < 0.001; sTNFRSF1B R = 0.53, P < 0.001), and in particular with the degree of renal dysfunction. In this study, there were no significant associations between the selected candidate TNF or TNF receptor polymorphisms, or their haplotypes, and susceptibility to sepsis, illness severity or outcome. The influence of polymorphisms of the TNF locus on susceptibility to, and outcome from sepsis remains uncertain.

Local activation of coagulation and inhibition of fibrinolysis in the lung during ventilator associated pneumonia.

BACKGROUND: Fibrin deposition is a hallmark of pneumonia. To determine the kinetics of alterations in local coagulation and fibrinolysis in relation to ventilator associated pneumonia (VAP), a single centre prospective study of serial changes in pulmonary and systemic thrombin generation and fibrinolytic activity was conducted in patients at risk for VAP. METHODS: Non-directed bronchial lavage (NBL) was performed on alternate days in patients expected to require mechanical ventilation for more than 5 days. A total of 28 patients were studied, nine of whom developed VAP. RESULTS: In patients who developed VAP a significant increase in thrombin generation was observed in the airways, as reflected by a rise in the levels of thrombin-antithrombin complexes in NBL fluid accompanied by increases in soluble tissue factor and factor VIIa concentrations. The diagnosis of VAP was preceded by a decrease in fibrinolytic activity in NBL fluid. Indeed, before VAP was diagnosed clinically, plasminogen activator activity levels in NBL fluid gradually declined, which appeared to be caused by a sharp increase in NBL fluid levels of plasminogen activator inhibitor 1. CONCLUSION: VAP is characterised by a shift in the local haemostatic balance to the procoagulant side, which precedes the clinical diagnosis of VAP.

Manipulation of CD98 expression affects both trophoblast cell fusion and amino acid transport activity during syncytialization of human placental BeWo cells.

The physiological importance of CD98 surface antigen in regulating placental trophoblast cell fusion and amino acid transport activity has been studied in parallel in a cell model of syncytialization (the cytotrophoblast cell line BeWo following increased intracellular cAMP by forskolin treatment) using antisense oligonucleotides. CD98 protein abundance (determined by Western blot) was decreased by 50 % following antisense oligonucleotide transfection. Transfection with antisense oligonucleotide altered the responses of BeWo to forskolin. Cell fusion (determined by a quantitative flow cytometry assay) was inhibited by 57 %, and both human chorionic gonadotropin secretion and L-leucine influx through system L were suppressed. These findings show that CD98 is involved in the process of cell fusion necessary for syncytiotrophoblast formation and that during this physiologically important event, amino acid transport activity is also regulated through expression of this membrane protein.

Attractiveness of 79 compounds and mixtures to wild Ceratitis capitata (Diptera: Tephritidae) in field trials.

Seventy-nine volatile compounds chosen from those emitted by Mediterranean fruit fly males, fruits and food baits, were tested for their attractiveness to females of Ceratitis capitata (Wiedemann) in field trials with a wild population. To correct for density fluctuations, the results were presented as a percentage of males caught in the same type of traps baited with trimedlure, a known male attractant. The mixtures of corn steep liquor with ammonia compounds and amines were the most effective attractants for females. Other compounds exhibiting C. capitata attraction were a mixture ethyl acetate+acetic acid+ethanol for both sexes, and p-cymene, 1,3-diethylbenzene and borneol for females.

Randomised double-blind comparison of ondansetron and droperidol to prevent postoperative nausea and vomiting associated with patient-controlled analgesia.

In a randomised, double-blind trial, we compared the use of ondansetron and droperidol for the prevention of nausea and vomiting after total abdominal hysterectomy, during patient-controlled analgesia with morphine. One hundred and forty-two patients were randomly allocated to one of two groups. All patients received a standardised general anaesthetic and postoperative analgesic regimen. One group received ondansetron 4 mg at induction of anaesthesia, and ondansetron 0.13 mg with each 1-mg bolus dose of morphine. The other group received droperidol 0.5 mg at induction and droperidol 0.05 mg per 1-mg bolus dose of morphine. Results were available for 137 patients. During the first 24 h after surgery, prophylaxis was successful in 26 of 66 patients given ondansetron (39%) compared with 36 of 71 patients given droperidol (51%). This difference was not statistically significant (Chi-squared = 1.766, p = 0.18). We conclude that in the regimens studied, ondansetron is not more effective than droperidol at preventing postoperative nausea and vomiting.

Triterpenoid compounds from Araujia sericifera B. Effects on the isolated guinea pig ileum.

Different fractions from the methanol insoluble extract of Araujia sericifera were obtained by chromatography and evaluated for their antihistaminic effects on guinea pig ileum in vitro. In order to determine the compounds responsible for the pharmacological effects observed, separation of the components from the active fraction was performed using HPLC.

Prevalence of hepatitis C in South Africa: detection of anti-HCV in recent and stored serum.

The prevalence of anti-HCV was studied in a cohort of 2,072 South Africans. The results were compared in selected recently collected sera and in stored sera. The serum ALT and anti-HBc were also studied as surrogate markers in this population. The following groups were tested: (a) 498 urban, black blood donors (b) 500 white blood donors (c) 500 Asian blood donors (d) 216 rural hospitalized patients (e) 358 rural mineworkers. Sera found positive by the original ELISA were retested, and reproducibly positive tests in rural black men (group d) were confirmed both by recombinant immunoblot assay and by a second ELISA. An anti-HCV prevalence of 1.2%, 0.8%, and 0.6% in urban blacks, Asians, and whites was found. Antibodies to hepatitis B core antigen were found in 42.9%, 3.4%, and 1.2% of black, Asian, and white donors, respectively; 76% of donors positive for anti-HCV were anti-HBc negative. In rural African men, 17% of stored serum samples and 9.2% of recently collected serum samples were positive for anti-HCV. In this cohort 3.84% were positive by all three assays. These results suggest that the prevalence of anti-HCV in low and high-risk South African urban blood donors is comparable to high and low prevalence areas in Europe, the United States, and Japan, but indicates a relatively high degree of exposure to hepatitis C in rural African men. The reactivity of stored, frozen sera in this population requires further investigation. In South African urban blood donors, surrogate marker testing will not expedite HCV screening.