Search

The reactions of C atoms and CH with NO, which are believed to be initial steps in the NO reburning reaction mechanism, were studied at high temperature behind reflected shock waves. C atoms were formed by pyrolysis or photolysis of dilute mixtures of C{sub 3}O{sub 2} in argon or by pyrolysis of dilute mixtures of CH{sub 4} in argon. CH was formed from the pyrolysis of dilute mixtures of CH{sub 4} or C{sub 2}H{sub 6} (

VR is an emerging technology that will greatly benefit the construction industry and its supply chain in terms of capacity to experiment, greatly improved communication, data visualisation and capturing ideas. This paper presents the outcome of a research project that was aimed at developing a ‘VR roadmap: vision for 2030 in built environment’. The methodology used was to thoroughly review previous and current application of VR in the construction and manufacturing based industries and conduct brain storming sessions with Experts in IT/VR regarding future functionalities and RD technology and process specifications towards 2030 and R&D plans to deliver such specifications. Discussions were focussed on identifying enablers, barriers, opportunities and challenges that prevail in the industry and those likely to be encountered towards 2030 with advancement of the technology and process changes. The paper introduces and discusses the roadmap and its related methodology.

A genital examination can have psychologic effects on a patient, particularly when the source of their sexual medicine complaint is a body part. How necessary is a physical exam before prescribing hormones in cases of gender dsyphoria?Five people with expertise and/or interest in the area of gender dysphoria and endocrinology were asked to contribute their opinions.To provide food for thought, discussion, and possible further research in a poorly discussed area of sexual medicine.Of the five experts writing on the topic, one believes that a physical examination should always be performed before prescribing hormones for gender dysphoria, one believes it is not a prerequisite, and three believe a physical examination is recommended, but is not necessary in cases where the patient objects despite an explanation of the purpose of the exam. As long as this was documented, it would not present a medicolegal problem.It is not clear whether or not a physical examination must be performed on all gender dsyphoric patients before prescribing hormones; however, an examination would be helpful in revealing a significant health management issue.

OBJECTIVE: To develop a contemporary, evidence-based definition of premature ejaculation (PE). METHODS: There are several definitions of PE; the most commonly quoted, the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders - 4th Edition - Text Revision, and other definitions of PE, are all authority-based rather than evidence-based, and have no support from controlled clinical and/or epidemiological studies. Thus in August 2007, the International Society for Sexual Medicine (ISSM) appointed several international experts in PE to an Ad Hoc Committee for the Definition of PE. The committee met in Amsterdam in October 2007 to evaluate the strengths and weaknesses of current definitions of PE, to critically assess the evidence in support of the constructs of ejaculatory latency, ejaculatory control, sexual satisfaction and personal/interpersonal distress, and to propose a new evidence-based definition of PE. RESULTS: The Committee unanimously agreed that the constructs which are necessary to define PE are rapidity of ejaculation, perceived self-efficacy, and control and negative personal consequences from PE. The Committee proposed that lifelong PE be defined as a male sexual dysfunction characterized by ejaculation which always or nearly always occurs before or within about one minute of vaginal penetration, and the inability to delay ejaculation on all or nearly all vaginal penetrations, and negative personal consequences, such as distress, bother, frustration and/or the avoidance of sexual intimacy. This definition is limited to men with lifelong PE who engage in vaginal intercourse. The panel concluded that there are insufficient published objective data to propose an evidence-based definition of acquired PE. CONCLUSION: The ISSM definition of lifelong PE represents the first evidence-based definition of PE. This definition will hopefully lead to the development of new tools and patient-reported outcome measures for diagnosing and assessing the efficacy of treatment interventions, and encourage ongoing research into the true prevalence of this disorder, and the efficacy of new pharmacological and psychological treatments.

Three cases of congenital cranial hemihypertrophy are described. CT or ultrasound scans showed unilateral cerebral enlargement with dilatation of the ipsilateral ventricle. Seizures occurred in two patients and the neurodevelopmental outlook appears poor. These patients represent a poor prognosis subgroup of the congenital hemihypertrophies.

A family is reported in which isolated hypogonadotrophic hypogonadism is inherited as an autosomal dominant condition with variable expression. In previous familial cases, inheritance was autosomal recessive. Comparison is made with the endocrine and genetic findings in Kallmann's syndrome, which should be considered a separate disorder. There is difficulty in drawing a sharp distinction between hypogonadotrophic hypogonadism and constitutional delay in puberty in this family.

Examining a patient or couple with sexual problems involves standard procedures. However, it can sometimes be fraught with difficulties, often related to psychological and social factors not generally experienced in other situations. ![][1] It is important to explain at the outset precisely what an examination entails. (Mercury treatment for venereal disease, circa 1500) Patients may anticipate the examination with dread and profound embarrassment or, conversely, may see it as a potential source of reassurance and relief. Doctors must be aware of the many popular myths about sex and that their patients may often hold quite idiosyncratic beliefs and fears, which will also need to be addressed. It is important to explain at the outset how the examination, essential in all patients with a suspected physical problem, might help them and to tell them precisely what it entails. An unusual history, odd behaviour by either partner during assessment, inconsistent findings on examination, or unexplained bruising or trauma may alert you to an abusive relationship. Any suspicions should not be ignored, but great care and sensitivity are needed to address this issue. #### Requirements for examination Many patients will find examination of the genitalia deeply embarrassing. Success will depend on the cooperation and confidence of your patient, and it is best to defer examination if the patient is uncomfortable and unable to relax. It is good practice to offer to have a chaperone present for both male and female … [1]: /embed/graphic-1.gif

Objective To evaluate the cost-effectiveness of combined resynchronisation and implantable defibrillator therapy for left ventricular dysfunction and explore subgroups in which such devices might be most cost-effective. Design Markov model-based economic evaluation. Setting UK NHS. Participants A simulated mixed age cohort of NYHA class III and IV patients with left ventricular systolic dysfunction and prolonged QRS interval. Main outcome measures Cost per quality adjusted life year gained over the patient lifetime. Results The incremental cost-effectiveness of resynchronisation therapy alone compared with optimal medical therapy was £16,735 (95% CI: £14,630 to £20,333) with a 91% probability of being cost-effective at a willingness to pay threshold of £30,000. Compared with resynchronisation alone, the incremental cost-effectiveness of combined implantable defibrillator was £40,160 (95% CI: £26,645 to £59,391) with only a 26% probability of cost-effectiveness at the £30,000 threshold. In a direct comparison across three treatments (medical treatment, resynchronisation alone and combined resynchronisation with implantable defibrillator therapy) resynchronisation alone was found to be the most cost-effective option. Conclusion Combined resynchronisation and implantable defibrillator therapy is not cost-effective for left ventricular dysfunction. Instead resynchronisation alone remains the most cost-effective policy option in this population. Combined devices are more likely to be cost-effective in the subgroups of younger patients or those with high risk of sudden cardiac death who would qualify for resynchronisation therapy.

Objectives: To assess life expectancy and cardiovascular mortality in carriers of Duchenne and Becker muscular dystrophy. Design: Family pedigrees of individuals affected with these conditions, held by the four genetics centres in Scotland, were examined to identify a cohort of definite carriers. Electronic death registration data, held by the General Register Office for Scotland, were used to identify death certificates of carriers who had died, to obtain age at death and cause of death. Survival and mortality data were obtained for the general population for comparison. Patients: 397 definite carriers in 202 pedigrees were identified from which 94 deaths were identified by record linkage to death certificates. Main outcome measures: Observed numbers surviving to certain ages and numbers dying of cardiac causes were compared with expected numbers calculated from general population data. Results: There were no significant differences between observed and expected numbers surviving to ages 40–90. The standardised mortality ratio for the 371 carriers alive in 1974 was 0.53 (95% confidence interval 0.32 to 0.82). Conclusions: Whereas female carriers may have clinical features of cardiomyopathy, this study does not suggest that this is associated with reduced life expectancy or increased risk of cardiac death. Routine cardiac surveillance of obligate carriers is therefore probably unnecessary.

The malformations found in fetal anticonvulsant syndromes (FACS) are associated with folic acid deficiency and methylene-tetrahydrofolate reductase (MTHFR) polymorphisms in the general population. To investigate a possible association between FACS and MTHFR genotype, we recruited 200 mothers who had taken anti-epileptic drugs in pregnancy, and delivered at Aberdeen Maternity Hospital over a 26-year period. Clinical findings in the mothers and their 337 children were documented. A clinical algorithm was devised to diagnose FACS objectively. Case-parent triads were genotyped for polymorphisms in MTHFR, serine hydroxymethyl transferase (SHMT1), methionine synthase (MTR), and methionine synthase reductase (MTRR), and analyzed by log-linear regression. No effect of the child's genotype on congenital malformation, neurodevelopmental disorder or FACS was detected using this method. The risk of having a child with congenital malformation or FACS was three to four times higher for mothers who were MTHFR 677TT homozygotes compared with MTHFR 677CC homozygotes. MTR 2756A > G and MTRR 66A > G genotype frequencies in children with FACS and neurodevelopmental disorder were different from those in healthy blood donor controls.

Progress on comprehensive validation of the short chemical kinetic mechanism for the JetA/air mixtures under conditions, typical of Pulsed Detonation Engines (PDE) operating conditions, is reported. The reduced (13 reactions, 15 species) kinetic mechanism (under development in Kurchatov Institute for the high fidelity simulations of the PDEs) is subjected to a specially designed, multi-step validation procedure. The results of the zerodimensional thermodynamic- and kinetic-based simulations are briefly described. This report discusses the procedures and the results of the one-dimensional reactive CFD validation of the reduced kinetic mechanism. For the 1-dimensional validation of the mechanism (as well as any other kinetic mechanism for any fuel), implemented in the computational fluid dynamics software (CFD software), the test data of detonation initiation behind reflected shock waves are proposed as proper detonation initiation validation measurements. The predictions show acceptable agreement with the available experimental measurements on detonation initiation in Jet-A/air mixtures. Additional investigation of the mechanisms of detonation formation behind reflected shock wave in 1-dimensional simulations allows to explain several experimental observations, which could not be explained before.

Marfan syndrome is a multisystem connective tissue disorder usually associated with mutation in fibrillin, and occasionally with mutation in TGFBR1 or 2. The clinical diagnosis is made using the Ghent nosology, which will unequivocally diagnose or exclude Marfan syndrome in 86% of cases. Use of a care pathway can help implementation of the nosology in the clinic. The penetrance of some features is age dependent, so the nosology must be used with caution in children. Molecular testing may be helpful in this context. The nosology cannot be used in families with isolated aortic dissection, or with related conditions such as Loeys-Dietz syndrome, although it may help identify families for further diagnostic evaluation because they do not fulfill the nosology, despite a history of aneurysm. Prophylactic medical (eg beta-blockade) and surgical intervention is important in reducing the cardiovascular complications of Marfan syndrome. Musculoskeletal symptoms are common, although the pathophysiology is less clear--for example, the correlation between dural ectasia and back pain is uncertain. Symptoms in other systems require specialist review such as ophthalmology assessment of refractive errors and ectopia lentis. Pregnancy is a time of increased cardiovascular risk for women with Marfan syndrome, particularly if the aortic root exceeds 4 cm at the start of pregnancy. High-intensity static exercise should be discouraged although low-moderate intensity dynamic exercise may be beneficial. The diagnosis and management of Marfan syndrome requires a multidisciplinary team approach, in view of its multisystem effects and phenotypic variability.

OBJECTIVE To evaluate the effect of vardenafil on both erectile function (EF) and treatment satisfaction (an aspect of quality of life) in men and their partners, as erectile dysfunction (ED) has a profound effect on patients’ quality of life and that of their partners, and treatment for ED tends to be focused on improving functional measures of EF. PATIENTS, SUBJECTS AND METHODS For this randomized, double-blind, placebo-controlled trial, men with ED for >6 months, according to the USA National Institutes of Health Consensus Statement, were recruited. In all, 611 patients were randomized to treatment with either vardenafil (10 mg for 4 weeks, titrated to preferred dose, 5, 10 or 20 mg, during the next 8 weeks, and maintained at preferred dose for the following 14 weeks), or placebo. RESULTS At 18 weeks (primary endpoint), the mean improvement in the EF domain of International Index of EF (IIEF-EF) vs baseline was significantly greater with vardenafil than placebo (12.70 vs 1.69, P

In accordance with AFI 63-104, the SEEK EAGLE Program is the standard for the aircraft-stores certification process of the United States Air Force (USAF). This program assures aircraft-store compatibility and includes engineering analyses, computer simulations, wind tunnel tests, and flight tests, when required. Part of the Air Force SEEK EAGLE Office (AFSEO) store certification process is the performance of a Compatibility Flight Profile (CFP) mission with the subject store flown on the aircraft it is to be certified on. The CFP mission profiles are developed by the Loads group of the AFSEO. The CFP mission requires subjecting the store in question to the maximum inertial and maximum aerodynamic loads throughout its intended flight envelope. The envelope will vary depending on the type of store being tested. For instance, an air-to-air missile must be demonstrated to Basic Aircraft Limits (BAL) while a bomb requires demonstration to significantly lower, and less risky, air-to-ground limits. The tests are performed in accordance with the guidelines set out in MIL-HDBKs-1763 and -244A. Recent aircraft-store compatibility programs that require BAL testing highlight the problem of balancing user requirements, engineering certification requirements, an aging USAF aircraft test fleet and the risk to aircraft and aircrews during BAL missions. Recent USAF aircraft-store compatibility programs that require BAL CFP missions have included AIM-9X, ECIPSU pylon and AIS pods. The Commander of the 40 Flight Test Squadron at Eglin Air Force Base, FL expressed his concern for subjecting his aging test fleet of F-16 jets to BAL missions and the increased risk to test pilots. Questions raised included: Were all the demo points necessary? Was BAL still a valid test requirement given that operational aircraft rarely spend time in this portion of the flight envelope? A BAL Process Action Team (PAT) was convened to investigate the BAL mission requirement. Air Combat Command (ACC) verified to the PAT that BAL was still a requirement for new stores such as the AIM-9X missile, FACE and T50 AIS pods. To balance test concerns and user requirements, the AFSEO Loads group re-evaluated the current BAL CFP mission profile. This included the possible elimination of test points, maneuvers, as well as performing maneuvers at different, less critical conditions while still providing the needed demo data. To determine what adjustments could be made, maneuver response data for

This paper documents recent advances towards an efficient computational method for accurately determining the static and dynamic stability and control (SC. In contrast to the “brute force” approach to filling an entire S&C database for an aircraft, the present approach is to reduce the number of simulations required to generate a complete aerodynamic model of a particular configuration at selected flight conditions by using one or a few complex dynamic motions and nonlinear system identification (SID) techniques. The approach is demonstrated by gathering high-fidelity computational fluid dynamics (CFD) data for a rigid F-16 in prescribed motion that approximates dynamic wind-tunnel testing techniques and SID input signals. The motions are optimized to minimize the computational expense and to take full advantage of the tighter control of the CFD environment. They are specified interactively using a newly developed, GUI-based maneuver file generation tool. Global nonlinear parameter modeling and other SID techniques are then used to identify parametric models from the computed aerodynamic force and moment data. These compact models are used to predict the aerodynamic response to maneuvers that were computed for validation purposes and that were not used to derive the models. Partial derivatives of the analytical models can be used to determine the corresponding static and dynamic stability derivatives. The models can also be used to perform real time 6-DOF/aeroelastic simulations of the vehicle in conditions susceptible to spin, tumble, and lateral/longitudinal instabilities. The main benefits of this effort are: 1) early discovery of complex aerodynamic phenomena that are typically only present in dynamic flight maneuvers and therefore not discovered until flight test, and 2) rapid generation of an accurate aerodynamic model to support aircraft and weapon certification by reducing required flight test hours and complementing current stability and control testing.

In a Pulse Detonation Engine (PDE), an exit nozzle enhances thrust generation, maintains operating pressure and also controls operating frequency. The performance of a PDE, under subsonic and supersonic flight conditions, was assessed using two parametric studies. The first of these parametric studies employs a 2D CFD model and quantifies the relative impact of four different but separate exit nozzle shapes namely a Converging and Diverging (CD) nozzle, a diverging nozzle, a straight nozzle and a converging nozzle where as a second parametric model uses a quasi-1D model for predicting the effect of a CD nozzle geometry parameters on the systems-level performance of a PDE. The 2D CFD performance model predictions for the subsonic flight (Mach number (Minf) = 0.8 and altitude (hinf) = 20 kft), using single pulse simulations of the detonation and the blowdown processes, show that the fuel-specific impulse Ispf, is higher for the case of a diverging nozzle when compared to all other nozzles. These results are in agreement with the results reported earlier [14,20] in the literature. The 2D CFD performance model predictions of a PDE under supersonic flight conditions (Minf = 3.0 and hinf = 30 kft), obtained using single pulse simulations of the detonation and the blowdown processes, show that the Ispf, total impulse and thrust generated are higher for the case of the diverging nozzle and the CD nozzle, when compared to the performance metrics of the straight nozzle or the diverging nozzle. A second parametric study employs the Q1D limit cycle model, and the exit CD nozzle contraction ratio (Rnc) is varied from 1.6 to 6.4. For the subsonic flight conditions, Ispf increases with increasing values of the exit nozzle contraction ratio and attains a constant value of 1600 for an exit nozzle contraction ratio of 3.0. For the supersonic flight conditions, Ispf increases with increasing values of the exit nozzle contraction ratio and attains a constant value of 1950 for Rnc > 5.0. The design choice of the optimum value for Rnc is predicted to be a compromise between optimizing the performance metric Ispf and generating the required thrust.

Experimental and computational studies of detonation initiation, using Deflagration-to-Detonation Tran sition (DDT) processes, were performed to investigate the effect of varying inlet parameters at elevated temp eratures and pressures on the run-up to detonation in hydrogen-air mixtures for a repeating detonation rig. It is found that the gasdynamic and chemical processes which effect the initial flame acceleration are the rate-li miting processes in determining the time scale of run-up t o detonation. A parametric study was performed in which the independent parameters of temperature, T (290 ‐ 615 K), pressure, P (1.0 ‐ 4.0 atm) and inlet fill velocity, Vb (10 ‐ 40 m/s) were systematically varied, and thei r effect on location, L DDT , and time of detonation, t DDT , initiation was quantified. A Pareto of effects in this parametric study shows variation in fill veloc ity and rig pressure have the largest effect on t DDT , while it shows variation in fill velocity and rig pressure followed by initial gas temperature have the largest effect on L DDT . Dimensionalized best-fit correlations were obtai ned from the test measurements for t DDT and L DDT as functions of P, T, and V. A nondimensional be st-fit correlations was obtained from the test measurements for t DDT as a function of key nondimensionalized independent variables, namely density expansion ratio α, a nondimensional length scale l/l F (where l is the integral length scale and l F is the laminar flame thickness) and a nondimensional velocity scale M (flow Mach number in the reactants) which govern the flow and chemical processes that occur during the DDT process.

Recent progress in several related research areas such as first‐principles electronic‐structure calculations of atoms and diatomic molecules, theory of elementary processes, kinetics, and numerical engineering, and also continued exponential growth in computational resources enhanced by recent advances in massively parallel computing have opened the possibility of directly designing kinetics mechanisms to describe chemical processes and light emission in such complex media as nonequilibrium plasmas and reacting gases. It is important that plasma and combustion kinetics can be described in the framework of this direct approach to a sufficiently high accuracy, which makes it an independent predictive research tool complementary to experimental techniques. This paper demonstrates the capabilities of the first‐principles based approach to develop kinetic mechanisms. Two examples are discussed in detail: (1) the mechanism of hydrocarbon fuel combustion at high temperatures and (2) light emission in non‐thermal glow discharge plasma of metal halides; special attention is paid to a comparison of the results obtained at every level of system description with the appropriate experimental data. In house software tools that can be used in such multilevel theoretical works are discussed as well.

A key concept envisioned for Pulse Detonation Engine (PDE) technology is a hybrid engine, where a Pulse Detonation Combustor (PDC) replaces the combustor in a conventional gas turbine. A systems level performance estimation model for a PDC-based hybrid engine cycle was presented. A variable property formulation was used to estimate the cycle performance parameters namely the thermal efficiency (ηth ) and the net specific work (Wnet ). Performance estimations were obtained using a one-step finite-rate chemistry to simulate reactions, and the frozen reactions assumption to model the products of combustion. Two specific parametric studies are performed in which the compression ratio (CR) and the purge fraction (pf) were systematically varied. The predicted variations of ηth and Wnet with varying compression ratio and purge fraction are in agreement with the trends reported in the literature. For a range of values of CR (1-40), performance (ηth ) advantage of a PDC-based hybrid engine is predicted, when compared to a conventional gas turbine engine. The present calculations show that the assumed unsteady turbine component efficiency (ηT ) for the case of a PDC-based hybrid engine has a large effect on ηth . An experimental study investigating the operation of a multi-tube PDC-turbine hybrid system was performed to understand the effect of unsteady flows entering the turbine on the turbine component performance (ηT ). An eight-tube PDC can-annular configuration was integrated with a single-stage axial turbine nominally rated for 10 lbm/s, 25000 RPM and 1000 hp. The system accumulated a total of 144 minutes of operation with long duration runs of approximately 5 minutes, in order for the rig to achieve thermal steady state and for the turbine to attain constant speed. The turbine component efficiency was found to be similar under PDC-fired operation and steady flow operation within the uncertainty of the measurement.Copyright © 2007 by ASME

Profit rather than need is a poor driver of clinical decision making, writes John Dean . Private practice also directly affects the care that NHS patients receive, he says—which is why he’s stopped doing it Ask any smoker: the last person they want to be with when lighting up is someone who has just quit. I sense a similar discomfort among some of my colleagues now that I have given up private medical practice. Like a lapsed Catholic shunned by the priesthood, I have become an apostate. I have always been ambivalent about private practice, and I had become increasingly uncomfortable about my own involvement. I realised that, in all conscience, I could not go on with it. No matter how high I set my own moral and ethical standards I could not escape the fact that I was involved in a business where the conduct of some was so venal, it bordered on criminal—the greedy preying on the needy. The business of medicine and the practice of medicine are at odds. Private medicine encourages doctors to make decisions on the basis of profit …

A routine detailed ultrasound examination performed at 20 weeks’ gestation demonstrated the presence of nuchal thickening as an apparently isolated finding. The concentration of maternal α -fetoprotein was normal and the risk of Down’s syndrome was 1 in 6800. Amniocentesis was performed and chromosome analysis showed the karyotype 46,XY, del(11)(q23) found in Jacobsen syndrome. Fetal autopsy performed following medical termination at 23 weeks confirmed the phenotype and internal abnormalities found in Jacobsen syndrome.

OBJECTIVE To evaluate, in a phase II study, the efficacy and safety of a topical eutectic mixture for premature ejaculation (TEMPE), a metered-dose aerosol spray containing a eutectic mixture of lidocaine and prilocaine, as a treatment for PE. PATIENTS AND METHODS Men with PE (Diagnostic and Statistical Manual-IV definition) aged 18–75 years were randomized into a double-blind, placebo-controlled study in the UK and the Netherlands. Efficacy variables included the mean change in intravaginal ejaculatory latency time (IELT) from baseline and the proportion of patients who achieved an IELT of ≥ 4, ≥ 3 or ≥ 2 min on two occasions, and the effect of TEMPE on the index of ejaculatory control (IEC) and sexual quality-of-life (SQoL) scores of patients and their partners. Safety and adverse event data were also collected. Fifty-four patients were randomized and received study treatment. RESULTS The observed mean change in IELT from baseline to the end of the treatment period was 3.8 min in the TEMPE group and 0.7 min in the placebo group, and when adjusted for baseline and centre was 2.4 times higher in the TEMPE than the placebo group (P

world's populations. The UK shows a pattern similar to that first seen in the USA, about half of adults in Britain are now estimated to be at an unhealthy weight (2). This is probably the result of cultural values, insufficient exercise, combined with an unbalanced proportion of calories/energy consumed vs energy expended. Weight gain can be subtle and insidious, increasing gradually over a long time, but remaining deleterious for overall health. Obesity is estimated to shorten life by an average of 9 years, i.e. 2 years more than prostate cancer. In the UK, ! 6% of all deaths can be attributed to obesity. Being overweight increases a man's risk of developing type 2 diabetes, high blood pressure, and several cancers (prostate included) as well as likely disturbances in lipid levels. It also increases the likelihood of osteoarthritis of the knees, hips and ankles, back pain and swelling of the legs. Although many people who are obese consume too many calories, their diet is often deficient in the nutrients essential for good health. A balanced diet includes three regular meals a day, providing lots of fruit, vegetables, whole-grains and less saturated fat. Recent studies showed that, in patients aged 70-90 years, adherence to a Mediterranean-type diet and healthy lifestyle lowered all-cause and cause-specific mortality by more than half (3). Excessive eating is just one example of conditioning and habituation that could be described as an 'addiction'. A pharmacological

Although sildenafil citrate (sildenafil) and tadalafil are efficacious and well-tolerated treatments for erectile dysfunction (ED), preference studies have shown that patients may favor one medication over the other.To determine whether psychosocial outcomes differed when men with ED received tadalafil compared with sildenafil.Measures included a treatment preference question, Psychological and Interpersonal Relationship Scales (PAIRS), and Drug Attribute Questionnaire.Randomized, open-label, crossover study. After a 4-week baseline, men with ED (N = 367; mean age = 54 years; naïve to type 5 phosphodiesterase inhibitor therapy) were randomized: tadalafil for 12 weeks then sildenafil for 12 weeks or vice versa (8-week dose optimization/4-week assessment phases). During dose optimization, patients started with 10 mg tadalafil, or 25 or 50 mg sildenafil and could titrate to their optimal dose (10 or 20 mg tadalafil; 25, 50, or 100 mg sildenafil). Medications were taken as needed. Patients completing both 12-week periods chose which medication to continue during an 8-week extension.Of 291 men completing both treatment periods, 71% (N = 206) chose tadalafil and 29% (N = 85) chose sildenafil (P0.001) for the 8-week extension. When taking tadalafil compared with sildenafil men had higher mean endpoint scores on PAIRS Sexual Self-Confidence (tadalafil = 2.91 vs. sildenafil = 2.75; P0.001) and Spontaneity (tadalafil = 3.32 vs. sildenafil = 3.17; P0.001) Domains and a lower mean endpoint score on Time Concerns Domain (tadalafil = 2.2 vs. sildenafil = 2.59; P0.001). The two most frequently chosen drug attributes to explain treatment preference were ability to get an erection long after taking the medication and firmness of erections. Tadalafil and sildenafil were well tolerated with 12 (3.3%) patients discontinuing for an adverse event.As measured with PAIRS, men with ED had higher sexual self-confidence and spontaneity and less time concerns related to sexual encounters when treated with tadalafil compared with sildenafil. These psychosocial outcomes may help explain why more men (71%) preferred tadalafil for the treatment of ED in this clinical trial.

A large-scale, multi-tube pulsed detonation combustor (PDC) with eight tubes arranged in a can-annular configuration was integrated with a single-stage axial turbine nominally rated for 10 lbm/s, 25000 RPM and 1000 hp. This PDC-turbine system was operated using ethylene-air mixtures with each tube firing at 20 Hz. High frequency pressure transducers were installed throughout the flow path to investigate the wave interactions at a range of conditions with three firing patterns: a single tube firing, all tubes firing simultaneously and all tubes firing sequentially. Analysis of these data revealed that wave interactions in the transition plenum between the PDC exit and turbine inlet plane can affect the optimum operation of the multi-tube PDC.

An experimental study was performed to investigate the mecha nical response of pulsed detonation engine (PDE) tubes to cyclic detonation loading using tubes of different material and thickness. A mechanical response rig was designed and tested at frequencies of 4, 5, 10, and 18 Hz using stainless steel, aluminum, a nd titanium tubes with outside diameters of 2” wall thicknesses of 0.120” and 0.035”. The effects of the propagation of a pure detonation wave versus the deflagration -to -detonation transition (DDT) process on tube strain were studied. Results show that hoo p strain was the most dominant response. A 30 -35 kHz resonance response was also measured, correlated with finite element simulation. and supported by literature findings. The present data suggest that cyclic detonation loading up to 40 Hz has no effect o n mechanical response when compared with single -shot detonation loading. Additionally, the strain during DDT was found to be an average of 50% higher than strain resulting from the propagation of a pure detonation wave.

The PDE exit nozzle maintains operating pressure and also controls operating frequency. Two parametric studies were performed for two flight Mach number (Minf) conditions of 0.8 and 3.0 and an altitude of 30 kft, in which the exit nozzle contraction ratio Rnc, was systematically varied from 1.6 to 6.4. For the supersonic flight Mach number of 3.0, fuel-specific impulse, Ispf, increases with increasing values of Rnc and attains a constant value of 1950 s for Rnc > 5.0. For the subsonic flight conditions of Minf = 0.8, Ispf increases with increasing values of the exit nozzle contraction ratio and attains a constant value of 1600 for an exit nozzle contraction ratio of 3.0. These parametric studies also quantified PDE operation parameters such as mass flowrates of air and fuel, frequency, and fill velocity. Two additional parametric studies were performed in which purge fraction and fill fraction were systematically varied and they show opposite effect on Ispf and thrust generated. The estimated Ispf was found to have a maximum of 1980 s at a flight Mach number of 3.0, and a minimum value of 1580 s, at a flight Mach number of 0.8 and an altitude of 30 kft.

A fiber-coupled mid-infrared (mid-IR) laser absorption sensor was designed to monitor ethylene and propane concentration in a multiple-cycle pulse detonation engine (PDE). The engine was operated at repetition rates ranging from 5 to 20 Hz with near-stoichiometric fuel/air mixtures. A 3.39 µm helium neon laser was fiber-coupled to the engine, enabling continuous, time-resolved measurements of fuel concentration. Design criteria are discussed to overcome sensor noise from optical emission, spark ignition, and the harsh mechanical vibrations of the fired engine. The sensor provides quantitative measurement of the stoichiometry to compare to PDE simulations and allows optimization of fuel valve timing and fill pressure for improved engine performance. Pulse-to-pulse interactions during fired engine tests can perturb the fuel loading compared to unfired tests, illustrating the need for in situ fuel monitoring for PDE development and testing.

An experimental and computational study regarding the operation of a Jet-A-fueled pulse detonation engine has been performed. In the experiments, liquid Jet-A fuel is injected into the head end of the engine in the form of atomized droplets. Preheated air serves to entrain and evaporate the fuel droplets, which are then spark ignited after traversing a finite length of pre-vaporizer section. The operation of the engine was investigated over a range of initial temperatures and pressures characteristic of high Mach-number operation or conventional gas turbine compressor discharge conditions. Pressure transducers and ionization probes were utilized to measure the absolute pressure rise and propagation speed of the combustion wave in order to verify detonation. Consistent and repeatable detonations have been observed in Jet-A / air mixtures at initial temperatures and pressures ranging from 225 - 312 F and 1.0 2.4 atm at frequencies up to 25 Hz. In addition, computational simulations of detonation propagation in an ideal-tube PDE fueled with Jet-A/air mixtures are presented.

A large-scale, multi-tube pulsed detonation combustor with eight tubes arranged in a can-annular configuration was integrated with a single-stage axial turbine nominally rated for 8 lbm/s, 25000 RPM and 1000 hp. This PDC-turbine system was operated using ethyleneair mixtures with each tube firing at 20 Hz. High frequency pressure transducers were installed throughout the flow path to investigate the wave interactions and attenuation across the turbine. The multi-tube PDC was operated at a range of conditions with three firing patterns: a single tube firing, all tubes simultaneous and all tubes sequential. Analysis of these data reveal wave interactions in the transition plenum between the PDC exit and turbine inlet plane can affect the optimum operation of the multi-tube PDC. In addition, there is over 20 dB attenuation of the peak pressure pulse and 10 dB attenuation of the broadband acoustic noise through the single-stage, axial flow turbine.

A key application for a Pulse Detonation Engine concept is envisioned as a hybrid engine, which replaces the combustor in a conventional gas turbine with a Pulse Detonation Combustor (PDC). A limit cycle model, based on quasi 1-D, unsteady Computational Fluid Dynamics (CFD) simulations, was developed to estimate the performance of a pressure-rise PDC in a hybrid engine to power a subsonic engine core. The parametric space considered for simulations of the PDC operation includes the mechanical compression or the flight conditions that determine the inlet pressure and the inlet temperature conditions, fill fraction and purge fraction. The PDC cycle process time scales including overall operating frequency were determined via limit-cycle simulations. The methodology for estimation of performance of the PDC considers the unsteady effects of PDC operation. These metrics include a ratio of time-averaged exit total pressure to inlet total pressure and a ratio of mass-averaged exit total enthalpy to inlet total enthalpy. This information can be presented as a performance map for the PDC, which was then integrated into a systems-level cycle analysis model, using Gate-Cycle, to estimate the propulsive performance of the hybrid engine. Three different analyses were performed. The first was a validation of the model against published data for specific impulse. The second examined the performance of a PDC versus a traditional Brayton cycle for a fixed combustor exit temperature; the results show an increased efficiency of the PDC relative to the Brayton cycle. The third analysis performed was a detailed parametric study varying engine conditions to examine the performance of the hybrid engine. The analysis has shown that increasing the purge fraction, which can reduce the overall PDC exit temperature, can simultaneously provide small increases in overall system efficiency.

A two -stage pulsed detonation device was assembled and examined in an experimental program. The device consisted of a precombustor, used to mix and burn a fuel-rich mixture, and a resonator designed to sustain high-frequency repeating detonations. The device was evaluated over a range of operating conditions and with a variety of fuels including natural gas, ethylene and liquid Jet-A. It was found that the addition of an initiator, consisting of a small tube PDE firing directly into the resonator, was necessary to produce high-speed wave combustion processes in the device. The addition of the initiator enabled the device to produce supersonic combustion waves at the resonator exit, however, the resulting wave speeds were not as high as calculated detonation speeds for the mixtures.

Bardet-Biedl syndrome (BBS) and Laurence-Moon syndrome (LMS) have a similar phenotype, which includes retinal dystrophy, obesity, and hypogenitalism. They are differentiated by the presence of spasticity and the absence of polydactyly in LMS. The aims of this study were to describe the epidemiology of BBS and LMS, further define the phenotype, and examine genotype-phenotype correlation. The study involved 46 patients (26 males, 20 females) from 26 families, with a median age of 44 years (range 1-68 years). Assessments were performed in 1986, 1993, and 2001 and included neurological assessments, anthropometric measurements, and clinical photographs to assess dysmorphic features. The phenotype was highly variable within and between families. Impaired co-ordination and ataxia occurred in 86% (18/21). Thirty percent (14/46) met criteria for psychiatric illness; other medical problems included cholecystectomy in 37% (17/46) and asthma in 28% (13/46). Dysmorphic features included brachycephaly, large ears, and short, narrow palpebral fissures. There was no apparent correlation of clinical or dysmorphic features with genotype. Two patients were diagnosed clinically as LMS but both had mutations in a BBS gene. The features in this population do not support the notion that BBS and LMS are distinct. The lack of a genotype-phenotype correlation implies that BBS proteins interact and are necessary for the development of many organs.