Success versus failure: Efficient heat devices in thermodynamics

Classical equilibrium thermodynamics provides, in a general way, upper Carnot bounds for the performance of energy converters. Nevertheless, to suggest lower bounds is a much more subtle issue, especially when they are related to a definition of convenience. Here, this issue is investigated in a unified way for heat engines, refrigerators, and heat pumps. First, irreversibilities are weighted in the context of heat reservoir stability for irreversible engines by using the thermodynamic distance between minimum energy and maximum entropy steady states. Some stability coefficients can be related to a majorization process and the obtention of Pareto fronts, linking stability and optimization by means of efficiency and entropy due to correlations between system and reservoirs. Second, these findings are interpreted in a very simple context. A region where the heat device is efficient is defined in a general scheme and, below this zone, the heat device is inefficient in the sense that irreversibilities somehow dominate its behavior. These findings allow for a clearer understanding of the role played by some well-known figures of merit in the scope of finite-time and -size optimization. Comparison with experimental results is provided.

Prevalence and predictors of right ventricular dysfunction in cancer patients treated with cardiotoxic chemotherapy – a prospective cardiovascular magnetic resonance study

Background

Right ventricular (RV) function has an established incremental prognostic value in cardiomyopathy. Studies on cancer therapeutics-related cardiac dysfunction (CTRCD) primarily focused on the left ventricle (LV), with conflicting results from small studies dedicated to RV dysfunction.

Purpose

We sought to investigate the influence of chemotherapy on RV function relative to LV function using serial cardiac magnetic resonance (CMR).

Methods

Patients were enrolled as part of Cardiotoxicity Prevention Research Initiative (CAPRI) Registry aimed at evaluating CMR-based markers for surveillance of CTRCD. Patients underwent non-contrast CMR imaging prior to initiation of anthracyclines and/or trastuzumab and serially every 3 months during the first year, then annually thereafter. We included patients who had a baseline and ≥1 follow-up scan and excluded those with baseline LV ejection fraction (EF)<50%, providing 320 patients completing 1,453 CMR studies. Cine images were analysed to calculate chamber volumes indexed to body surface area and EF. We defined LV CTRCD using CMR modality specific criteria of a drop in LV EF ≥5% from baseline to <57%; RV CTRCD as a drop ≥5% to <49% in females and <47% in males. We used linear mixed models to study the changes in ventricular volumes and EF with time.

Results

The majority of patients were females (80%), had breast cancer (68%) or lymphoma (32%), with a mean age of 52.7±13 years. Figure 1 shows temporal changes in mean ventricular volumes and function over the first year. Mean changes in RV function followed those of the LV, with the nadir of EF and maximum of volumes occurring at 6 months. Respective values for mean decrease in LV and RV EF at this time point versus baseline were 4.1 and 2.9% (p<0.001). Concomitant mean increase in indexed RV end-diastolic (ED) and end-systolic (ES) volumes were 1.6 and 2.7 ml/m2 (p=0.2 and <0.001). There was significant interaction of chemotherapy regimen with time for RV volumes (p=0.001 and 0.003), but not RV EF (p=0.7), with worst changes occurring with combined anthracyclines and trastuzumab. In all, 70 (22%) and 28 (9%) patients met criteria for LV and RV CTRCD, respectively. Among those who developed RV CTRCD, 10 had persistently normal LV function. Figure 2 shows the results of logistic regression to predict RV CTRCD. Significant univariable predictors included combined chemotherapy regimen and baseline LV and RV volumes and LV EF. Adjusting for age, sex, and chemotherapy regimen, baseline RV ED volume remained associated with RV CTRCD (odds ratio 1.6; p=0.005).

Conclusion

In this large study, RV volumes and function were similarly influenced by chemotherapy versus comparable LV-based measures. Using similar threshold criteria, the incidence of RV CTRCD was lower than for LV CTRCD; however, one third of those who develop RV CTRCD showed normal LV function. Future studies are warranted to study the prognostic influence of RV injury in cancer patients.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Alberta InnovatesGenome Alberta Figure 1. Temporal changes in LV & RV functionFigure 2. Predictors of RV CTRCD

4941Machine learning based automated diagnosis of ischemic vs non-ischemic dilated cardiomyopathy using 3D myocardial deformation analysis

Background

Late Gadolinium Enhancement (LGE) imaging is a reference standard technique for the differentiation of ischemic cardiomyopathy (ICM) from non-ischemic dilated cardiomyopathy (NIDCM) in patients with heart failure and reduced ejection fraction (HFrEF). 3D myocardial deformation analysis (3D-MDA) offers highly reproducible phenotypic assessments of regional architecture and function that may provide value for artificial-intelligence-assisted cardiomyopathy diagnosis without need for LGE imaging.

Purpose

In this study, we trained and validated a machine-learning-based model to enable automated diagnosis of ischemic versus non-ischemic dilated cardiomyopathy exclusively using regional patterns of deformation among patients otherwise matched by age, sex and global contractile dysfunction.

Methods

100 ICM and 100 NIDCM patients matched for age, sex, and LVEF underwent standard cine SSFP and LGE imaging. Patient diagnoses were established using a combination of clinical and LGE-based criteria. 3D-MDA was performed using validated software (GIUSEPPE) to compute regional 3D strain measures at each cardiac phase in both conventional and principal strain directions. Principal Component Analysis (PCA) was performed on the composite 3D-MDA dataset. The first 20 components were chosen, accounting for approximately 65% of the population variance. Subsequently, a support-vector-machine-based algorithm was used with 10-fold cross-validation to discriminate ICM from NIDCM.

Results

Patients were 63±10 years (ICM: 63±10 years, NIDCM: 63±10 years, p=0.955), 74% male (ICM: 74%, NIDCM: 74%, p=1.000), and had a mean LVEF of 27±8% (ICM: 27±7%, NIDCM: 28±7%, p=0.688). Global time to peak strain was significantly shorter in ICM patients relative to NIDCM patients across all surfaces and in all directions (p<0.05). The highest single-variable Area Under the Curve (AUC) achieved for the classification of ICM versus NIDCM from global data was for minimum principal strain (ICM: 43.7±7.8, NIDCM: 48.3±7.5, p<0.001, AUC: 0.682) (Figure 1). However, a multi-feature machine-learning-based model exposed to all available regional 3D deformation data achieved an AUC of 0.903 (sensitivity 87.7%, specificity 75.5%).

Conclusions

Machine learning-based analyses of3D regionaldeformation patterns allows for robust discrimination of ICM versus NIDCM. Further expansion of the presented findings is planned on a wider, multi-centre cohort.

Acknowledgement/Funding

Dr. White was supported by an award from Heart and Stroke Foundation of Alberta. This study was funded in part by Calgary Health Trust.

2019 European guideline on the management of lymphogranuloma venereum

New or important issues in this updated version of the 2013 European guideline on the management of lymphogranuloma venereum (LGV): EPIDEMIOLOGY: Lymphogranuloma venereum continues to be endemic among European men who have sex with men (MSM) since 2003. Lymphogranuloma venereum infections in heterosexuals are extremely rare in Europe, and there is no evidence of transmission of LGV in the European heterosexual population.

AETIOLOGY AND TRANSMISSION

Chlamydia trachomatis serovars/genovars L2b and L2 are the causative strains in the majority of cases in Europe.

CLINICAL FEATURES

Among MSM, about 25% of the anorectal LGV infections are asymptomatic. Genital infections among MSM are rare; the ratio of genital vs. anorectal LGV infections is 1 in 15.

DIAGNOSIS

To diagnose LGV, a sample tested C. trachomatis positive with a commercial nucleic acid amplification test (NAAT) platform should be confirmed with an LGV discriminatory NAAT.

TREATMENT

Doxycycline 100 mg twice a day orally for 21 days is the recommended treatment for LGV. This same treatment is recommended also in asymptomatic patients and contacts of LGV patients. If another regimen is used, a test of cure (TOC) must be performed.

2nd BASHH Oxford Diagnostics Course, November 2015

The second British Association for Sexual Health and HIV Oxford Diagnostics Course of 2015 focussed on recent challenges and emerging concepts within diagnostics and service design. In response to increasing sexually transmitted infection rates and subsequent demand on UK sexual health services, multiple approaches to improving patient flow and reducing waiting times were presented. The value of novel remote sexually transmitted infection testing was explored, with a description of the patient journey, emerging demographics and rates of testing uptake for the UK's leading National Health Service provider. A cost-benefit evaluation was made for the use of nucleic acid amplification tests versus traditional microscopy and culture for detecting Trichomonas vaginalis, with practical consideration of application to higher risk groups. Two speakers stressed the importance of vigilance against growing antimicrobial resistance. The significance of testing for genotypic markers for antimicrobial resistance, and the emergence of point-of-care tests for resistance were also presented. The meeting closed with a first-hand account of tendering, and practical advice on rebuilding professional relationships and services after a competitive process.

Numerical study of the most stable contact angle of drops on tilted surfaces

We present results for the most stable contact angle using a numerical implementation of the tilting plate method of Montes et al. (Montes Ruiz-Cabello, F. J.; Rodriguez-Valverde, M. A.; Cabrerizo-Vilchez, M. Soft Matter 2011, 7, 10457-10461). Comparison with the experimental results is made, obtaining a good agreement in most situations. In addition, the evolution of the contact angles of a tilted drop with a fixed circular line is analyzed. This analysis allows one to theoretically predict the most stable contact angle for tilted drops.

Multiple endosymbiont infections and reproductive manipulations in a linyphiid spider population

In many arthropods, maternally inherited endosymbiotic bacteria can increase infection frequency by manipulating host reproduction. Multiple infections of different bacteria in a single host population are common, yet few studies have documented concurrent endosymbiont phenotypes or explored their potential interactions. We hypothesized that spiders might be a particularly useful taxon for investigating endosymbiont interactions, because they are host to a plethora of endosymbiotic bacteria and frequently exhibit multiple infections. We established two matrilines from the same population of the linyphiid spider Mermessus fradeorum and then used antibiotic curing and controlled mating assays to demonstrate that each matriline was subject to a distinct endosymbiotic reproductive manipulation. One matriline was co-infected with Rickettsia and Wolbachia and produced offspring with a radical female bias. Antibiotic treatment eliminated both endosymbionts and restored an even sex ratio to subsequent generations. Chromosomal and fecundity observations suggest a feminization mechanism. In the other matriline, a separate factorial mating assay of cured and infected spiders demonstrated strong cytoplasmic incompatibility (CI) induced by a different strain of Wolbachia. However, males with this Wolbachia induced only mild CI when mated with the Rickettsia-Wolbachia females. In a subsequent survey of a field population of M. fradeorum, we detected these same three endosymbionts infecting 55% of the spiders in almost all possible combinations, with nearly half of the infected spiders exhibiting multiple infection. Our results suggest that a dynamic network of endosymbionts may interact both within multiply infected hosts and within a population subject to multiple strong reproductive manipulations.

The impact of proposed changes in liver allocation policy on cold ischemia times and organ transportation costs

Changes to the liver allocation system have been proposed to decrease regional variation in access to liver transplant. It is unclear what impact these changes will have on cold ischemia times (CITs) and donor transportation costs. Therefore, we performed a retrospective single center study (2008-2012) measuring liver procurement CIT and transportation costs. Four groups were defined: Local-within driving distance (Local-D, n = 262), Local-flight (Local-F, n = 105), Regional-flight <3 h (Regional <3 h, n = 61) and Regional-Flight >3 h (Regional >3 h, n = 53). The median travel distance increased in each group, varying from zero miles (Local-D), 196 miles (Local-F), 384 miles (Regional <3 h), to 1647 miles (Regional >3 h). Increasing travel distances did not significantly increase CIT until the flight time was >3 h. The average CIT ranged from 5.0 to 6.0 h for Local-D, Local-F and Regional <3 h, but increased to 10 h for Regional >3 h (p < 0.0001). Transportation costs increased with greater distance traveled: Local-D $101, Local-F $1993, Regional <3 h $8324 and Regional >3 h $27 810 (p < 0.0001). With proposed redistricting, local financial modeling suggests that the average liver donor procurement transportation variable direct costs will increase from $2415 to $7547/liver donor, an increase of 313%. These findings suggest that further discussion among transplant centers and insurance providers is needed prior to policy implementation.

Lack of Utility of Routine Screening Tests for Early Detection of Peritonitis in Patients Requiring Intermittent Peritoneal Dialysis

A prospective study was undertaken to examine the clinical presentation of peritonitis in patients maintained on intermittent peritoneal dialysis and to determine the value of qualitative and quantitative dialysate cultures, gram stain, neutrophil counts, and a semiquantitative leukocyte test strip for case detection. Seven cases of peritonitis developed among 30 patients who underwent 553 dialyses. In most cases, neutrophil counts, cultures, and leukocyte test strip determinations were done within 48 hours prior to the clinical onset of peritonitis and in all instances failed to provide clues for incipient infection. Peritonitis was associated with a dialysate neutrophil count of >500/mm3 and leukocyte test strips were highly sensitive and specific for the detection of this quantity of neutrophils. A total of 16 dialysate cultures was positive in asymptomatic patients who did not have peritonitis. None of these patients subsequently developed peritonitis with the same organism. Dialysate gram stains, cultures, neutrophil counts or leukocyte test strips did not provide an early diagnosis of peritonitis and their use in the absence of symptoms is therefore not recommended.

Genital ulcers: it is not always simplex …

Patients with vulval aphthae, also termed Lipschütz ulcers, often present to genitourinary medicine clinics. Typically, these ulcers present as acute, painful, vulval ulcers in young women and adolescents. The aetiology is unknown, and often these ulcers are accompanied by flu-like symptoms. Previous case reports have linked such lesions to acute viral infections such as Epstein-Barr virus, cytomegalovirus and influenza A. We report the first case of influenza B virus and adenovirus infections associated with this presentation.

Risk factors for rectal lymphogranuloma venereum in gay men: results of a multicentre case-control study in the U.K

Objective

To identify risk factors for rectal lymphogranuloma venereum (rLGV) in men who have sex with men (MSM).

Design

A case-control study at 6 UK hospitals compared MSM with rLGV (cases) with rLGV-negative controls: MSM without potential rLGV symptoms (CGa) and separately, MSM with such symptoms (CGs).

Methods

Between 2008 and 2010, there were 90 rLGV cases, 74 CGa and 69 CGs recruited. Lifestyles and sexual behaviours in the previous 3 months were reported using internet-based computer-assisted self-interviews. Logistic regression was used to investigate factors associated with rLGV.

Results

Cases were significantly more likely to be HIV-positive (89%) compared with CGa (46%) and CGs (64%). Independent behavioural risks for rLGV were: unprotected receptive anal intercourse (adjusted OR (AOR)10.7, 95% CI 3.5 to 32.8), fisting another (AOR=6.7, CI 1.8 to 25.3), sex under the influence of gamma-hydroxybutyrate (AOR=3.1, CI 1.3 to 7.4) and anonymous sexual contacts (AOR=2.7, CI 1.2 to 6.3), compared with CGa; unprotected insertive anal intercourse (AOR=4.7, CI 2.0 to 10.9) and rectal douching (AOR=2.9 CI 1.3 to 6.6), compared with CGs. An incubation period from exposure to symptoms of 30 days was indicated.

Conclusions

Unprotected receptive anal intercourse is a key risk factor for rectal LGV with the likelihood that rectal-to-rectal transmission is facilitated where insertive anal sex also occurs. The association between HIV and rLGV appears linked to HIV-positive men seeking unprotected sex with others with the same HIV status, sexual and drug interests. Such men should be targeted for frequent STI screening and interventions to minimise associated risks.

Recreational drug use in men who have sex with men (MSM) attending UK sexual health services is significantly higher than in non-MSM

INTRODUCTION

The aim of this study was to investigate the pattern of recreational drug use in patients attending a genitourinary medicine clinic, and to determine whether drug use was greater among men who have sex with men (MSM) patients, when compared to non-MSM male patients.

METHODS

A questionnaire was given to all patients attending the genitourinary medicine clinics at two inner city teaching hospitals over 3 months (July to September 2011). The questionnaire was self-completed by patients while waiting to be seen by a clinician. Data were collected on age, gender, gender of sexual partner(s), and previous/current recreational drug use (type/frequency of drugs used). Only data from male respondents have been analysed in this paper.

RESULTS

1328 questionnaires were completed. Of the male respondents (n=729), 475 (65.2%) were identified as non-MSM and 254 (34.8%) were identified as MSM. The mean ± SD age of male respondents was 31 ± 9 years years. Lifetime and last month use of mephedrone, ketamine, volatile nitrites ('poppers'), sildenafil (Viagra), GHB, and GBL were all significantly higher in the MSM group compared to the non-MSM group. Lifetime use of cocaine powder, MDMA, amphetamine, and methamphetamine were also significantly higher in the MSM group; however, there was no significant difference in last month use of these drugs between MSM and non-MSM groups.

CONCLUSIONS

Both lifetime and last month use of most recreational drugs was more common in MSM, when compared to non-MSM males. Sexual health clinics may provide an opportunistic encounter to identify patterns of recreational drug use, explore motivations for use, and implement strategies to reduce harms related to drug use. This will require a multidisciplinary approach to address the psychosocial aspects of drug taking behaviours, in combination with healthcare professionals experienced in the management of recreational drug use.

Does the ‘2012 IUSTI ECCG report on the diagnosis and management of Neisseria gonorrhoeae infections in Europe’ depict the situation in Europe?

Summary

Gonorrhoea is a major public health concern globally. Of particular grave concern is that resistance to the third generation cephalosporins has been identified during recent years. This paper summarises and discusses the results of the ‘2012 IUSTI European Collaborative Clinical Group (ECCG) report on the diagnosis and management of Neisseria gonorrhoeae infections in Europe’. Although high quality care was reported in many settings, in several other countries the testing, diagnostics, antimicrobial treatment and follow-up of gonorrhoea patients need to be optimized. This, together with increased access to and use of antimicrobial susceptibility testing, is crucial in controlling the emergent spread of cephalosporin-resistant and multidrug-resistant gonorrhoea.

Lymphogranuloma venereum detected from the pharynx in four London men who have sex with men

Summary

Lymphogranuloma venereum (LGV) is an established cause of proctitis in men who have sex with men (MSM). Currently in the UK, testing for pharyngeal Chlamydia trachomatis (CT) is not routine, and LGV typing is usually only performed in patients with anorectal symptoms. We report four cases where LGV-associated CT DNA was detected from the pharynx in MSM, demonstrating that nucleic acid amplification testing (NAAT) can be used for detecting and typing pharyngeal CT infection. These cases also highlight other possible routes of infection for LGV, and add to the broad spectrum of clinical presentations associated with this infection.

Performance of the GeneXpert CT/NG assay compared to that of the Aptima AC2 assay for detection of rectal Chlamydia trachomatis and Neisseria gonorrhoeae by use of residual Aptima Samples

There are currently no commercially available molecular assays for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae in rectal swabs with regulatory approval. We compared the Cepheid GeneXpert CT/NG assay with the GenProbe Aptima Combo2 assay, using 409 rectal swabs. Using Aptima as the gold standard, the sensitivity, specificity, and positive and negative predictive values of GeneXpert for the detection of C. trachomatis and N. gonorrhoeae were 86%, 99.2%, 92.5%, and 98.4% and 91.1%, 100%, 100%, and 98.6%, respectively. Despite significant dilution of samples prior to GeneXpert testing, the assay performed well with excellent specificity.

Simulation analysis of contact angles and retention forces of liquid drops on inclined surfaces

A simulation study of liquid drops on inclined surfaces is performed in order to understand the evolution of drop shapes, contact angles, and retention forces with the tilt angle. The simulations are made by means of a method recently developed for dealing with contact angle hysteresis in the public-domain Surface Evolver software. The results of our simulations are highly dependent on the initial contact angle of the drop. For a drop with an initial contact angle equal to the advancing angle, we obtain results similar to those of experiments in which a drop is placed on a horizontal surface that is slowly tilted. For drops with an initial contact angle equal to the mean between the advancing and the receding contact angles, we recover previous results of finite element studies of drops on inclined surfaces. Comparison with experimental results for molten Sn-Ag-Cu on a tilted Cu substrate shows excellent agreement.

Theory and simulation of angular hysteresis on planar surfaces

A simple model is proposed to simulate contact angle hysteresis in drops on a planar surface. The model is based on assuming a friction force acting on the triple contact line in such a way that the contact line keeps fixed for contact angles comprised between the advancing angle and the receding one and is allowed to move in order to avoid angles outside this interval. The model is straightforwardly applied to axisymmetric drops for which a simple solution of the Young-Laplace equation can be obtained. A variation of the method has also been implemented for nonaxisymmetric drops by resorting to the public-domain "Surface Evolver" software. Comparison with experiments shows the excellent performance of the model.

Entropic selectivity of binary mixtures in cylindrical pores

We show that a simple model consisting of a binary hard-sphere mixture in a narrow cylindrical pore can lead to strong size selectivity by considering a situation where each species of the mixture sees a different radius of the cylinder. Two mechanisms are proposed to explain the observed results depending on the radius of the cylinder: for large radii the selectivity is driven by an enhancement of the depletion forces at the cylinder walls whereas for the narrowest cylinders excluded-volume effects lead to a shift of the effective chemical potential of the particles in the pore.

Seven days of doxycycline is an effective treatment for asymptomatic rectal Chlamydia trachomatis infection

There are no evidence-based guidelines for the specific management of rectal Chlamydia trachomatis (CT) infection. All men who have sex with men (MSM) diagnosed with asymptomatic rectal CT by nucleic acid amplification test (NAAT) at a large London genitourinary (GU) medicine clinic between September 2006 and September 2009 were offered oral doxycycline 100 mg twice daily for seven days and invited for a test of cure (TOC) by CT NAAT four weeks after treatment. A total of 487 asymptomatic rectal CT infections were diagnosed and analysis was restricted to 165 TOCs from men whose only treatment had been doxycycline for seven days. The median time post-treatment for TOC was 45 days (interquartile range [IQR], 34–88). Only two patients tested CT-positive at follow-up. One had taken doxycycline only for three days; the other attended for TOC 240 days after the completion of doxycycline treatment and at this time presented with new symptoms in the context of ongoing high sexual risk. Our findings show that doxycycline 100 mg twice daily for seven days is highly effective treatment for asymptomatic rectal CT infection, achieving clearance of CT in 98.8% (163/165; 95% CI 95.4–99.9%) of cases. We advocate doxycycline for seven days as first-line therapy for asymptomatic rectal CT.

First Principles Computer Simulation of the Defect Chemistry of Rutile TiO2

There exists a long-standing controversy concerning the nature of the dominant point defect mechanism in rutile TiO2. Previous classical shell model calculations by Catlow el al [1] find a strong preference for Schottky as opposed to Frenkel-type defects, lending support for oxygen vacancy rather than titanium interstitial compensation in reduced rutile. However, reviews of experimental studies [2], show that many conflicting conclusions have been reached. Ab initio total-energy calculations have been performed on a parallel computer to help resolve this controversy. First results indicate a Schottky formation energy (of the bound Schottky trio) consistent with the Mott-Littleton values of Catlow et al [1]. A first attempt is made at calculating the heat of reduction through determination of the formation energy of a neutral oxygen atom vacancy. As a. result some interesting insight is gained into the redox chemistry of reduced rutile.

Endosymbiont costs and benefits in a parasitoid infected with both Wolbachia and Cardinium

Theory suggests that maternally inherited endosymbionts can promote their spread and persistence in host populations by enhancing the production of daughters by infected hosts, either by improving overall host fitness, or through reproductive manipulation. In the doubly infected parasitoid wasp Encarsia inaron, Wolbachia manipulates host reproduction through cytoplasmic incompatibility (CI), but Cardinium does not. We investigated the fitness costs and/or benefits of infection by each bacterium in differentially cured E. inaron as a potential explanation for persistence of Cardinium in this population. We introgressed lines infected with Wolbachia, Cardinium or both with the cured line to create a similar genetic background, and evaluated several parasitoid fitness parameters. We found that symbiont infection resulted in both fitness costs and benefits for E. inaron. The cost was lower initial egg load for all infected wasps. The benefit was increased survivorship, which in turn increased male production for wasps infected with only Cardinium. Female production was unaffected by symbiont infection; we therefore have not yet identified a causal fitness effect that can explain the persistence of Cardinium in the population. Interestingly, the Cardinium survivorship benefit was not evident when Wolbachia was also present in the host, and the reproduction of doubly infected individuals did not differ significantly from uninfected wasps. Therefore, the results of our study show that even when multiple infections seem to have no effect on a host, there may be a complex interaction of costs and benefits among symbionts.

Preoperative embolization of cerebral arteriovenous malformations with onyx

BACKGROUND AND PURPOSE

Preoperative embolization facilitates the surgical management of complex cerebral arteriovenous malformations (cAVMs). This analysis aims to investigate the risks for preoperative cAVM embolization with Onyx.

MATERIALS AND METHODS

We retrospectively analyzed clinical data of all patients who underwent embolization with Onyx as a preoperative treatment of cAVMs at our institution since 2005 (US Food and Drug Administration [FDA] approval). Patients with arteriovenous fistulas were excluded. A total of 107 patients were treated for cAVMs during the study period. Of those patients, 41 underwent cAVM embolizations with Onyx in 82 procedures.

RESULTS

After the embolization, the cAVM diameter was reduced from 3.71 +/- 1.55 cm to 3.06 +/- 1.89 cm (P < .05). Median volume reduction was 75%. Complete occlusion with embolization alone was achieved in 4 (10%) cAVMs. The recurrence rate for completely occluded cAVMs was 50% (2 patients). A total of 71% of the 41 patients treated with Onyx underwent surgery, and 15% underwent radiosurgery. There were 9% who have not yet received definitive treatment of their residual cAVMs. A new permanent neurologic deficit occurred in 5 patients (6.1% per procedure or 12.2% per patient).

CONCLUSIONS

A considerable risk for a permanent neurologic deficit remains for cAVM embolization with Onyx. The risk has to be carefully weighted against the benefit of volume reduction in the treatment of cAVMs.

Cytoplasmic incompatibility in the parasitic wasp Encarsia inaron: disentangling the roles of Cardinium and Wolbachia symbionts

Many bacterial endosymbionts of insects are capable of manipulating their host's reproduction for their own benefit. The most common strategy of manipulation is cytoplasmic incompatibility (CI), in which embryonic mortality results from matings between uninfected females and infected males. In contrast, embryos develop normally in infected females, whether or not their mate is infected, and infected progeny are produced. In this way, the proportion of infected females increases in the insect population, thereby promoting the spread of the maternally inherited bacteria. However, what happens when multiple endosymbionts inhabit the same host? The parasitoid wasp Encarsia inaron is naturally infected with two unrelated endosymbionts, Cardinium and Wolbachia, both of which have been documented to cause CI in other insects. Doubly infected wasps show the CI phenotype. We differentially cured E. inaron of each endosymbiont, and crossed hosts of different infection status to determine whether either or both bacteria caused the observed CI phenotype in this parasitoid, and whether the two symbionts interacted within their common host. We found that Wolbachia caused CI in E. inaron, but Cardinium did not. We did not find evidence that Cardinium was able to modify or rescue Wolbachia-induced CI, nor did we find that Cardinium caused progeny sex ratio distortion, leaving the role of Cardinium in E. inaron a mystery.

Disseminated gonococcal infection in a homosexual man diagnosed by nucleic acid amplification testing from a skin lesion swab

Disseminated gonococcal infection (DGI) often presents a diagnostic challenge. Through the novel application of molecular technology, a case is presented that suggests how the diagnostic sensitivity for this systemic complication of gonococcal infection can be improved. In a typical case of DGI seen in a homosexual man in whom all mucosal and blood specimens were culture negative, nucleic acid amplification testing (NAAT) helped to confirm the diagnosis. Both throat and skin lesion specimens tested positive for gonococcal DNA and this was confirmed with a supplementary porA pseudogene NAAT. The use of adjuvant NAAT assessment is recommended as part of the diagnostic work-up for suspected DGI cases.

A reconnaissance survey of the woody flora and vegetation of the Catapú logging concession, Cheringoma District, Mozambique

A checklist of the trees, shrubs and Hanes of Catapú, Cheringoma District, Mozambique, is presented. Floristically the study area falls within the Swahilian/Maputaland Regional Transition Zone. In total, 238 woody species and infraspecific taxa have been recorded, representing 59 families and 167 genera. Most species (64%) occur both to the north and south of the study area. 26% have their core distribution in the Swahilian Regional Centre of Endemism, 4% have a more southerly distribution. 14 are endemic to the Swahilian/Maputaland Regional Transition Zone and two near-endemic, extending into the Zambezian Regional Centre of Endemism only along the Zambezi River Valley as far west as Kariba. The checklist includes the Sena names for 191 species, 77 of which are recorded for the first time. Comparisons of the Catapú checklist are made with other checklists.

Density functional theory of fluids in nanopores: Analysis of the fundamental measures theory in extreme dimensional-crossover situations

Two density functional theories, the fundamental measures theory of Rosenfeld [Phys. Rev. Lett. 63, 980 (1989)] and a subsequent approximation by Tarazona [Phys. Rev. Lett. 84, 694 (2000)] are applied to the study of the hard-sphere fluid in two situations: the cylindrical pore and the spherical cavity. The results are compared with those obtained with grand canonical ensemble Monte Carlo simulations. The differences between both theories are evaluated and interpreted in the terms of the dimensional crossover from three to one and zero dimensions.

Finite-size effects in the microscopic structure of a hard-sphere fluid in a narrow cylindrical pore

We examine the microscopic structure of a hard-sphere fluid confined to a small cylindrical pore by means of Monte Carlo simulation. In order to analyze finite-size effects, the simulations are carried out in the framework of different statistical mechanics ensembles. We find that the size effects are specially relevant in the canonical ensemble where noticeable differences are found with the results in the grand canonical ensemble (GCE) and the isothermal isobaric ensemble (IIE) which, in most situations, remain very close to the infinite system results. A customary series expansion in terms of fluctuations of either the number of particles (GCE) or the inverse volume (IIE) allows us to connect with the results of the canonical ensemble.

Plasma membrane voltage changes during nanosecond pulsed electric field exposure

The change in the membrane potential of Jurkat cells in response to nanosecond pulsed electric fields was studied for pulses with a duration of 60 ns and maximum field strengths of approximately 100 kV/cm (100 V/cell diameter). Membranes of Jurkat cells were stained with a fast voltage-sensitive dye, ANNINE-6, which has a subnanosecond voltage response time. A temporal resolution of 5 ns was achieved by the excitation of this dye with a tunable laser pulse. The laser pulse was synchronized with the applied electric field to record images at times before, during, and after exposure. When exposing the Jurkat cells to a pulse, the voltage across the membrane at the anodic pole of the cell reached values of 1.6 V after 15 ns, almost twice the voltage level generally required for electroporation. Voltages across the membrane on the side facing the cathode reached values of only 0.6 V in the same time period, indicating a strong asymmetry in conduction mechanisms in the membranes of the two opposite cell hemispheres. This small voltage drop of 0.6-1.6 V across the plasma membrane demonstrates that nearly the entire imposed electric field of 10 V/mum penetrates into the interior of the cell and every organelle.

On the universal behavior of some thermodynamic properties along the whole liquid-vapor coexistence curve

When thermodynamic properties of a pure substance are transformed to reduced form by using both critical- and triple-point values, the corresponding experimental data along the whole liquid-vapor coexistence curve can be correlated with a very simple analytical expression that interpolates between the behavior near the triple and the critical points. The leading terms of this expression contain only two parameters: the critical exponent and the slope at the triple point. For a given thermodynamic property, the critical exponent has a universal character but the slope at the triple point can vary significantly from one substance to another. However, for certain thermodynamic properties including the difference of coexisting densities, the enthalpy of vaporization, and the surface tension of the saturated liquid, one finds that the slope at the triple point also has a nearly universal value for a wide class of fluids. These thermodynamic properties thus show a corresponding apparently universal behavior along the whole coexistence curve.

Density functional theory of fluids in the isothermal-isobaric ensemble

We present a density functional theory for inhomogeneous fluids at constant external pressure. The theory is formulated for a volume-dependent density, n(r,V), defined as the conjugate variable of a generalized external potential, nu(r,V), that conveys the information on the pressure. An exact expression for the isothermal-isobaric free-energy density functional is obtained in terms of the corresponding canonical ensemble functional. As an application we consider a hard-sphere system in a spherical pore with fluctuating radius. In general we obtain very good agreement with simulation. However, in some situations a peak develops in the center of the cavity and the agreement between theory and simulation becomes worse. This happens for systems where the number of particles is close to the magic numbers N=13, 55, and 147.

Platelet glycoprotein IIb/IIIa inhibition in acute coronary syndromes. Gradient of benefit related to the revascularization strategy

AIMS

To assess the efficacy of platelet glycoprotein IIb/IIIa inhibitors in patients with acute coronary syndromes primarily medically managed.

METHODS AND RESULTS

We performed a meta-analysis of the randomized clinical trials of platelet glycoprotein IIb/IIIa inhibitor therapy in the medical management of non-ST-elevation acute coronary syndromes. Among 29570 patients, IIb/IIIa integrin blockade was associated with a reduction in death or non-fatal myocardial infarction at 30 days, from 11.5% to 10.7% (odds ratio 0.91,P =0.02). Patients undergoing percutaneous coronary intervention during index hospitalization sustained a greater reduction in ischaemic events (odds ratio 0.82, P=0.01) than patients medically managed (odds ratio 0.95, P=0.27). Among patients undergoing intervention, the benefit was more pronounced if the procedure was performed during glycoprotein IIb/IIIa inhibitor infusion (odds ratio 0.74; P=0.02), than if revascularization was performed after drug discontinuation (odds ratio 0.87,P =0.17).

CONCLUSION

This analysis, including the entire large-scale trial experience of intravenous glycoprotein IIb/IIIa inhibitors in patients with acute coronary syndromes primarily medically managed, demonstrates an overall significant, albeit moderate, reduction in 30-day death or myocardial infarction associated with therapy. Although not based on a prospectively defined hypothesis, the findings suggest a gradient of benefit conferred by these agents depending on the revascularization strategy used.