Cryogenic and hermetically sealed packaging of photonic chips for optomechanics.

We demonstrate a hermetically sealed packaging system for integrated photonic devices at cryogenic temperatures with plug-and-play functionality. This approach provides the ability to encapsulate a controlled amount of gas into the optical package allowing helium to be used as a heat-exchange gas to thermalize photonic devices, or condensed into a superfluid covering the device. This packaging system was tested using a silicon-on-insulator slot waveguide resonator which fills with superfluid 4He below the transition temperature. To optimize the fiber-to-chip optical integration 690 tests were performed by thermally cycling optical fibers bonded to various common photonic chip substrates (silicon, silicon oxide and HSQ) with a range of glues (NOA 61, NOA 68, NOA 88, NOA 86H and superglue). This showed that NOA 86H (a UV curing optical adhesive with a latent heat catalyst) provided the best performance under cryogenic conditions for all the substrates tested. The technique is relevant to superfluid optomechanics experiments, as well as quantum photonics and quantum optomechanics applications.

Convergent evolution of pain-inducing defensive venom components in spitting cobras.

Convergent evolution provides insights into the selective drivers underlying evolutionary change. Snake venoms, with a direct genetic basis and clearly defined functional phenotype, provide a model system for exploring the repeated evolution of adaptations. While snakes use venom primarily for predation, and venom composition often reflects diet specificity, three lineages of cobras have independently evolved the ability to spit venom at adversaries. Using gene, protein, and functional analyses, we show that the three spitting lineages possess venoms characterized by an up-regulation of phospholipase A2 (PLA2) toxins, which potentiate the action of preexisting venom cytotoxins to activate mammalian sensory neurons and cause enhanced pain. These repeated independent changes provide a fascinating example of convergent evolution across multiple phenotypic levels driven by selection for defense.

Modeling observations of solar coronal mass ejections with heliospheric imagers verified with the Heliophysics System Observatory.

We present an advance toward accurately predicting the arrivals of coronal mass ejections (CMEs) at the terrestrial planets, including Earth. For the first time, we are able to assess a CME prediction model using data over two thirds of a solar cycle of observations with the Heliophysics System Observatory. We validate modeling results of 1337 CMEs observed with the Solar Terrestrial Relations Observatory (STEREO) heliospheric imagers (HI) (science data) from 8 years of observations by five in situ observing spacecraft. We use the self-similar expansion model for CME fronts assuming 60° longitudinal width, constant speed, and constant propagation direction. With these assumptions we find that 23%-35% of all CMEs that were predicted to hit a certain spacecraft lead to clear in situ signatures, so that for one correct prediction, two to three false alarms would have been issued. In addition, we find that the prediction accuracy does not degrade with the HI longitudinal separation from Earth. Predicted arrival times are on average within 2.6 ± 16.6 h difference of the in situ arrival time, similar to analytical and numerical modeling, and a true skill statistic of 0.21. We also discuss various factors that may improve the accuracy of space weather forecasting using wide-angle heliospheric imager observations. These results form a first-order approximated baseline of the prediction accuracy that is possible with HI and other methods used for data by an operational space weather mission at the Sun-Earth L5 point.

Isolation and characterization of renin-like aspartic-proteases from Echis ocellatus venom.

Three aspartic proteases (SVAPs) have been isolated from venom of the saw-scaled viper, Echis ocellatus. In confirmation of prior transcriptomic predictions, all three forms match to sequences of either of the two SVAP transcripts (EOC00051 and EOC00123), have a molecular weight of 42 kDa and possess a single N-glycan. The SVAPs act in a renin-like manner, specifically cleaving human and porcine angiotensinogen into angiotensin-1 and possess no general protease activity. Their activity is completely inhibited by the aspartyl protease inhibitor Pepstatin A.

Fluorescence technologies for evaluating male gamete (dys)function.

For many years, andrologists have sought ways of assessing sperm fertility, especially of new sires entering the breeding chain. As knowledge of the complex processes that enable sperm to fertilize eggs has increased, it has become clearer that quantitative estimation of the fertilizing potential of a sire or an ejaculate is actually unlikely ever to be fully realized. Here, we propose that a better approach is to identify substandard males and semen samples. During the past decades, the use of fluorescence technologies in biomedical science has burgeoned, with the development of very powerful instrumentation such as confocal microscopy and flow cytometers of ever-increasing capabilities together with a vast range of fluorochromes and fluorochrome conjugates. This technology has been applied to andrology but thus far in only a relatively simple way. In this review, we offer strategies for assessing a large range of sperm functions thought to be related to fertilizing ability over a temporal window rather than at a single time point. From such an assessment profile, sperm samples that over-respond or do not respond sufficiently could be identified, termed dysfunctional and rejected. We outline the rationales behind such tests, present information on new potentially useful fluorochromes and current flow cytometer models that would be suitable for the multicolour multifunctional tests we propose, and we offer suggestions as to how andrologists might design such multicolour tests for themselves.

Mathematical analysis of mis-estimation of cell subsets in flow cytometry: viability staining revisited.

Many research projects in cell biology now use flow cytometry for analysis or for isolation of specific cell types. In such studies, cell viability is obviously a crucial issue. However, many studies appear to rely upon light-scattering characteristics to identify and gate out non-viable cells, despite the fact that reliable identification of such cells can only be achieved through staining with impermeable fluorescent nuclear dyes such as propidium iodide or 7-amino actinomycin. In this paper we apply mathematical analysis to the theoretical problem of quantifying cell sub-populations labeled with two or more fluorescent markers, comparing situations in which dead cells have been identified with those in which cell viability has not been assessed. We demonstrate that in all cases in which dead cells are present within the population, percentages of live sub-populations in different subsets are mis-estimated. In cases where the pattern of marker expression differs greatly between live and dead cells, or where the proportion of dead cells is high, this mis-estimation will be aggravated; the subsets pattern will therefore be biased in a population selected only on the basis of light-scatter behavior. The importance of accurately detecting and gating out dead cells is illustrated by an experimental example accompanying the mathematical analysis. To conclude, identification of dead cells by means of viability stains should be an absolute routine in practical flow cytometry, so as to avoid mis-estimation in sorting or analysis.

Cytometric solutions in veterinary andrology: Developments, advantages, and limitations.

Cytometric methodologies are becoming increasingly important in veterinary andrology as means of assessing sperm function. However, as yet, flow cytometric techniques in veterinary andrology have not kept up in sophistication with those in other areas of biology and medicine. In this brief review, we consider the present state of cytometry in andrological procedures for evaluating the fertility of domestic animal sires. We outline the aspects of sperm physiology, paying particular attention to the changes that take place during the process known as capacitation, which prepares the sperm for interaction with the egg. We then examine briefly but critically the cytometric techniques that are currently in commercial use or are being established in research laboratories for testing sperm characteristics. Current limitations and potential developments in semen assessment are discussed. Recent research knowledge offers possibilities for applying more subtle flow cytometric approaches to distinguish different levels of fertilizing potential in semen samples. For example, linking field fertility data to multiparametric kinetic studies of sperm capacitational changes rather than "single parameter-single time point" estimations may reveal that slower rather than rapid changes indicate high fertility. Moreover, the development of multicolor flow cytometric procedures as a means of evaluating multiple functional parameters in individual cells would reduce the uncertainties always inherent in predicting fertility from in vitro sperm evaluation tests.

Systematic misestimation of cell subpopulations by flow cytometry: a mathematical analysis.

Various sources of variability in flow cytometric determination of cell concentration have previously been investigated with respect to andrologic applications. Although common aspects related to the variation between samples, variation between operators, and accuracy have been extensively studied, specific sources of false-count estimation have found less attention. In particular, a major and well-recognized source of misestimation of cell counts (i.e., contamination of the sample by non-sperm particles) has not to date been characterized in detail. We show here by means of original mathematical research that not only the cell counts but also the percentages of cells expressing different fluorescence patterns are affected by the presence of alien particles often neglected in studies involving flow cytometric characterization. We demonstrate that there is a systematic overestimation in the proportion of unstained (viable) cells detected by flow cytometry in cases where the non-sperm particles are not excluded from analysis by additional identification other than light-scatter characteristics. Moreover, we provide an exact mathematical estimate for the magnitude of this overestimation, and we discuss the consequences for diagnostic applications and studies on sperm physiology, specifically for studies on sperm capacitation and evaluation of cryopreserved semen. Finally, equations are derived for the correction of the flow cytometric values for use in practical applications.

Cryobiological determinants of frozen semen quality, with special reference to stallion.

Success in cryopreserving stallion semen has been very variable. Several different freezing regimes have been published. However, because extenders and procedures used in each regime have differed, direct comparison of these techniques has been very difficult, and controlled studies comparing different techniques have not been reported. A number of different factors affect sperm cryosurvival. In this article we review briefly current cryopreservation procedures for stallion semen, and then in more detail cryobiological determinants of sperm function, and mechanisms of cryoinjury and cryoprotectant action. Specific attention is given to data relating to stallion sperm. The complexity of sperm cell biology is believed to be an important factor when developing improvements in stallion semen cryopreservation. It may be assumed that impairment of cell function resulting from cold and osmotic shock is a main source of stallion sperm sensitivity to conventional freezing procedures. Further physiological studies on stallion sperm are required to understand the mechanisms by which cryopreservation alters sperm function and influences selection of sperm with higher fertilizing potential. Such studies should focus especially on the processes involved in sperm volume regulation, sperm-oviduct interaction, capacitation and cellular signalling, and on the alterations in these processes caused by cryopreservation.

Attitudes and behaviour of ophthalmologists to smoking cessation.

AIMS: Growing evidence suggests a causal association between smoking and eye disease. This study explores the current beliefs and practice among UK consultant ophthalmologists towards delivering smoking cessation advice to eye clinic attenders. METHODS: A cross-sectional survey using a postal questionnaire of all UK NHS hospital based consultant ophthalmologists was conducted. The questionnaire explored whether: ophthalmologists identify the smoking status of their patients, advise about the increased risk of eye diseases among smokers, and deliver smoking cessation advice. The availability of departmental smoking cessation resources was also ascertained. RESULTS: The response rate was 55% (485/886). Of the responders 79% were males. Only 35% of responders asked about smoking status every time or most times for new patients and 5% for follow-up patients. In all, 40% claimed to always or usually advise patients to quit smoking and 61% claimed to always or usually mention eye disease as a reason to quit. Only 14% assessed motivation to quit and 22% provided advice and assistance about how to stop smoking to smokers who wished to quit. Female ophthalmologists were more likely to undertake most aspects of smoking assessment and intervention. Only 18% of responders stated that their departments provide information about smoking for patients and 6% stated that support is available for patients wanting to quit smoking. CONCLUSION: The assessment of smoking status and provision of targeted support for smokers to quit could be substantially improved in UK ophthalmology departments. There is a need to introduce smoking cessation support into routine ophthalmic practice and provide the resources to support this.

Attitudes of community optometrists to smoking cessation: an untapped opportunity overlooked?

AIM: To assess community optometrists' attitudes and current behaviour regarding provision of smoking cessation advice in their practice. METHODS: A self-completion postal questionnaire was sent to community optometrists in north-west England identified from the General Optical Council's practice lists. RESULTS: Of 709 optometrists identified, 71.8% (509/709) returned the completed questionnaire. Few community optometrists routinely asked about smoking habits: only 6.2% (95% CI: 4.1-8.3) (n = 31) at new patient consultations, and 2.2% (95% CI: 0.9-3.5) (n=11) at follow-up visits. Reasons for optometrists not routinely providing smoking cessation advice included: not their role (35.4%, n=180), lack of time (22.0%, n=112) and forgetting to ask (21.4%, n=109). Overall 67.6% (95% CI: 63.5-71.7) (n=344) of community optometrists wanted to improve their knowledge of smoking and visual impairment with 56.2% (95% CI: 51.9-60.5) (n=286) requesting further training. CONCLUSION: Despite low levels of current involvement, many optometrists were keen to receive training on smoking cessation topics. We suggest that there are untapped opportunities to develop brief interventions to promote smoking cessation services in community optometry settings.

Effects of bromodichloromethane on ex vivo and in vitro luteal function and bromodichloromethane tissue dosimetry in the pregnant F344 rat.

Bromodichloromethane (BDCM), a drinking water disinfection by-product, causes pregnancy loss, i.e. full-litter resorption, in F344 rats when treated during the luteinizing hormone (LH)-dependent period. This effect is associated with reduced maternal serum progesterone (P) and LH levels, suggesting that BDCM disrupts secretion of LH. To test the hypothesis that BDCM also affects luteal responsiveness to LH, we used ex vivo and in vitro approaches. For the ex vivo study (i.e., in vivo exposure followed by in vitro assessment), dams were dosed by gavage on gestation days (GD) 6-9 (plug day=GD 0) at 0 or 100 mg/kg/d. One hour after the GD-9 dose, rats were killed, blood was collected, and tissue concentrations of BDCM were assessed. Corpora lutea (CL) were incubated with or without hCG, an LH agonist, to stimulate P secretion. For the in vitro study, CL were pooled from untreated F344 rats on GD 9 and cultured with BDCM at 0, 0.01, 0.10 or 3.0 mM. BDCM was found at highest concentrations in adrenal, ovarian, adipose, and hypothalamic tissues. BDCM treatment decreased serum P and LH levels in vivo. Ex vivo, however, BDCM-exposed CL showed >2-fold increases in P secretion relative to controls. Both control and BDCM-exposed CL displayed a 2.4-fold increase in P secretion in response to hCG challenge. In contrast, in vitro exposures reduced CL responsiveness in a dose-related fashion while baseline levels were unaffected. It is unclear if the ex vivo 'rebound' reflects the removal of the CL from a possible direct inhibitory influence of BDCM, or a response to diminished LH stimulation in vivo. Thus, these data suggest that BDCM disrupts pregnancy in F344 rats via two modes: disruption of LH secretion, and disruption of the CL's ability to respond to LH.

Signalling pathways involved in the control of sperm cell volume.

The ability to maintain cellular volume is an important general physiological function, which is achieved by specific molecular mechanisms. Hypotonically induced swelling results in the opening of K+ and Cl- ion channels, through which these ions exit with accompanying water loss. This process is known as regulatory volume decrease (RVD). The molecular mechanisms that control the opening of the ion channels in spermatozoa are as yet poorly understood. The present study investigated pathways of osmo-signalling using boar spermatozoa as a model. Spermatozoa were diluted into isotonic and hypotonic Hepes-buffered saline in the presence or absence of effector drugs, and at predetermined intervals volume measurements were performed electronically. Treatment with protein kinase C (PKC) inhibitors staurosporine, bismaleimide I and bismaleimide X led to dose-dependent increases of both isotonic and hypotonic volumes (P<0.05). However, as the isotonic volume was affected more than the hypotonic volume, the kinase inhibitors appeared to improve RVD, whereas activation of PKC with phorbol dibutyrate blocked RVD. The increase in isotonic cell volume induced by bismaleimide X was observed in chloride-containing medium but not in the medium in which chloride was replaced by sulphate, implying that PKC was involved in the control of chloride channel activity, e.g. by closing the channel after volume adjustment. The protein phosphatase PP1/PP2 inhibitors calyculin and okadaic acid increased the isotonic volume only slightly but they greatly increased the relative cell volume and blocked RVD. The activation of RVD processes was found to be cAMP-dependent; incubation with forskolin and papaverine improved volume regulation. Moreover, papaverine was able to overcome the negative effect of protein phosphatase inhibitors. The mechanism of sperm RVD appears to involve (a) alterations in protein phosphorylation/dephosphorylation balance brought about by PKC and PP1 and (b) a cAMP-dependent activating pathway.

Cigarette smoking and thyroid eye disease: a systematic review.

PURPOSE: To evaluate the epidemiological evidence for a causal association between tobacco smoking and thyroid eye disease (TED). METHODS: Systematic review, including quality assessment, of published epidemiological studies and evaluation of the evidence using established causality criteria. RESULTS: Fourteen papers describing 15 studies were included. There was a positive association between smoking and TED in four case-control studies when compared with control patients with Graves' disease but no ophthalmopathy (odds ratio (OR) 1.94-10.1) and in seven case-control studies in which control subjects did not have thyroid disease (OR 1.22-20.2). Two cohort studies examined the occurrence of new cases of TED; one study found an increased incidence of TED with smoking. Four cohort studies investigated progression or outcome of treatment in patients with established TED, three finding an association between smoking and poorer outcome. The quality of the studies was variable, but the association with smoking was strong in the most methodologically rigorous studies. Other evidence supporting a causal link was a consistent association across studies, a dose-response effect, a reduced risk of TED in ex-smokers, and a temporal relationship. CONCLUSION: This systematic review provided strong evidence for a causal association between smoking and development of TED. Current-smokers were also more likely to experience disease progression or poorer outcome of treatment. Patients with Graves' disease and the general public should be educated about the risk of smoking and TED. These findings suggest that patients with Graves' disease or TED who are smokers should be given effective support to stop smoking.

Tongxinluo (Tong xin luo or Tong-xin-luo) capsule for unstable angina pectoris.

BACKGROUND: Tongxinluo capsule is a medicine consisting of traditional Chinese herbs and insects used for cardiovascular diseases in China and some other Asian countries. To date the evidence of its effect has not previously been subject to systematic review, making it difficult to derive robust conclusions about its actual benefits, and indeed, possible harms. OBJECTIVES: To assess systematically the effects of tongxinluo capsule in people with unstable angina pectoris. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library, Issue 4 2004, MEDLINE, EMBASE, Chinese Biomedical Database, China National Knowledge Infrastructure, Japana Centra Revuo Medicina (all 1995 to 2005). We also handsearched the relevant Chinese journals, checked with manufacturers and registers of ongoing studies. SELECTION CRITERIA: Randomised trials comparing either tongxinluo capsule only or standard treatment plus tongxinluo capsule with standard treatment or other anti-angina pectoris drugs, placebo or no intervention. DATA COLLECTION AND ANALYSIS: Two authors identified relevant studies for the review independently and went on to abstract data, and assess trial quality. Authors of included studies were contacted to obtain further information as required. MAIN RESULTS: 18 short term follow-up trials involving 1413 people were included. The studies did not provide strong support of a benefit of tongxinluo for reducing the combined outcome of acute myocardial infarction, angioplasty (PTCA) coronary artery bypass graft (CABG) and sudden death or all-cause mortality (RR 0.42, 95% CI 0.07 to 2.59, P=0.35; RR 0.33, 95% CI 0.01to 7.78, P=0.49, respectively). Tongxinluo reduced the frequency of acute angina attacks (WMD -1.20, 95%CI -1.38 to -1.02, P<0.00001 and RR -2.36, 95%CI -2.53 to -2.18, P<0.00001, respectively), improved ECG (RR 1.31, 95% CI 1.08 to 1.57, P=0.005) and angina symptoms (RR 1.21, 95% CI 1.06 to 1.40; P=0.007). AUTHORS' CONCLUSIONS: Tongxinluo in combination with routine angina therapy appears to reduce the risk of subsequent AMI, PTCA or CABG, angina attacks and severity, as well as improving symptoms and ischaemic changes on the electrocardiogram (ECG). Due to the methodological limitations of the studies, the evidence is insufficient to make any conclusive recommendations about the use of this treatment for patients presenting with unstable angina. Large high quality randomised controlled trials are warranted.

Pleasure or pain? A profile of smokers in Northern England.

OBJECTIVE: To construct a profile of smokers using multiple indices of physical, mental and social health. STUDY DESIGN: Cross-sectional study. METHODS: The setting was Wigan and Bolton Health Authority, an urban district in the North West of England. A random sample of over 15000 adults from the Health Authority adult population completed a written questionnaire. Prevalence ratios were calculated for physical, mental and social health indicators for smokers compared with non-smokers, adjusted for borough, age and deprivation score of place of residence. RESULTS: Smokers were less likely to report their current health as good, and reported a significantly higher prevalence of arthritis, bronchitis, backache and respiratory symptoms. Smokers had more mobility problems and recent severe pain. Smokers had less healthy lifestyles across many behaviours (e.g. poorer diet, taking less regular exercise and more problem drinking). Depression and the proportion of people with a high psychiatric morbidity score were increased. More women smokers reported a lack of social support, and smokers more often reported financial difficulties. Differences were exaggerated by comparing heavy smokers with non-smokers. CONCLUSIONS: Independent of the level of deprivation of their area of residence, smokers have poorer physical, social and mental health, with a dose-response effect. Smoking creates considerable pain, but little evidence of pleasure.

Neutralisation of venom-induced haemorrhage by IgG from camels and llamas immunised with viper venom and also by endogenous, non-IgG components in camelid sera.

Envenoming by snakes results in severe systemic and local pathology. Intravenous administration of antivenom, prepared from IgG of venom immunised horses or sheep, is the only effective treatment of systemic envenoming. Conventional antivenoms, formulated as intact IgG, papain-cleaved (Fab) or pepsin-cleaved F(ab')2 fragments, are however ineffective against the local venom effects because of their inability to penetrate the blood/tissue barrier. We have embarked on a new research program to examine (i) whether the unusually small (15 kDa) antigen-binding fragment of camelid heavy chain IgG (V(H)H) can be exploited to neutralise the local effects of envenoming and (ii) whether a novel antivenom to treat both the systemic and local effects of envenoming can be formulated by combining anti-snake venom V(H)H and conventional F(ab')2. In this preliminary study, we demonstrate that camels and llamas respond to immunisation with Echis ocellatus venom with high antibody titres and broad antigen specificity. These encouraging immunological results were matched by the successful elimination of venom-induced haemorrhage by IgG from the venom-immunised camels and llamas. Unexpectedly, we report for the first time that camelid serum contains a non-IgG, highly potent inhibitor of venom-induced haemorrhage.

Planning to win: Health and lifestyles associated with physical activity amongst 15,423 adults.

STUDY OBJECTIVE: To assess levels of physical activity in the general population and amongst the 'healthy', and to identify factors associated with this important health behaviour. DESIGN: Population-based cross-sectional study. SETTING: North-west England. PARTICIPANTS: Adults (aged at least 18 years) registered with a general practitioner with a residential address within two local administrative districts (local authorities). MAIN RESULTS: Less than one-third of adults performed adequate amounts of physical activity for health protection, and this differed little when analyses were restricted to 'healthy' people. Lower levels of physical activity were observed amongst women, older people, ethnic groups, those with obesity and in each increased quintile of social deprivation. Current smokers, but not previous smokers, were less likely to be physically active, as were those not eating at least five portions of fruit and vegetables per day. Lack of physical activity was associated with poor general health and a history of, or current, chronic disease. CONCLUSIONS: Concerted efforts are required by the Government, society and individuals to overturn our predominantly physically inactive adult population. Interventions may be needed which specifically target certain groups, especially the most socially deprived, and that consider individuals and societal barriers to becoming physically active. Evidence of the effectiveness of individual and population-based interventions remains scant and this needs to be addressed urgently.