Computational Screening of a Single-Atom Catalyst Supported by Monolayer Nb2S2C for Oxygen Reduction Reaction.

The search for high-performance catalysts to improve the catalytic activity for an oxygen reduction reaction (ORR) is crucial for developing a proton exchange membrane fuel cell. Using the first-principles method, we have performed computational screening on a series of transition metal (TM) atoms embedded in monolayer Nb2S2C to enhance the ORR activity. Through the scaling relationship and volcano plot, our results reveal that the introduction of a single Ni or Rh atom through substitutional doping into monolayer Nb2S2C yields promising ORR catalysts with low overpotentials of 0.52 and 0.42 V, respectively. These doped atoms remain intact on the monolayer Nb2S2C even at elevated temperatures. Importantly, the catalytic activity of the Nb2S2C doped with a TM atom can be effectively correlated with an intrinsic descriptor, which can be computed based on the number of d orbital electrons and the electronegativity of TM and O atoms.

Third-generation modular mandible endoprosthesis in Macaca fascicularis.

The aim of this study was to develop a third-generation modular mandible endoprosthesis that would experience less stress concentration at its stems compared to earlier generations, thereby minimizing micromotion and achieving long-term stability. In this three-piece modular design, different degrees of movement were incorporated between the endoprosthesis module interfaces. It was hypothesized that this unique feature would minimize stress concentration at the stems and hence promote osseointegration during the early phase of implantation. The endoprosthesis system was made of commercially pure grade 4 titanium, machined and surface-treated, then sterilized and implanted in segmental mandible defects of nine Macaca fascicularis. Clinical, radiological, histological, and histomorphometric evaluations were performed 4 months post-implantation. The endoprosthesis systems with a degree of movement incorporated, exhibited superior performance compared to the rigid system: 30.9-34.8 times higher percentage bone-implant contact (P< 0.0001) and 3.4-4.1 times higher percentage bone area (P<0.0001), with osseointegration noted at the posterior stems. However, fibrous tissue encapsulation was noted around the majority of the anterior stems in all groups. Although the degree of movement was favourable for improving bone healing and stability of the endoprosthesis system, more work needs to be done to investigate other strategies to further reduce loading on the endoprosthesis to achieve predictable osseointegration at the stems.

Structural control of the dielectric, pyroelectric and ferroelectric properties of poly(vinylidene fluoride-co-trifluoroethylene) thin films.

The effects of solvents and temperature on the crystal formation were investigated for vinylidene fluoride/trifluoroethylene copolymer P(VDF-TrFE). Highly crystalline P(VDF-TrFE) thin films were fabricated by spin-casting using various polar solvents such as diethyl carbonate (DEC), methyl ethyl ketone (MEK), N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). Ferroelectric polarisation reversal of the P(VDF-TrFE) was evidenced by a displacement (D)-electric field (E) hysteresis loop measurement and supported by the presence of pyroelectric activity. The samples which were annealed above 100 °C gave elongated rod-like crystalline structures and the highest crystallinity, Xc of 83% was formed at 120 °C. Consequently, remnant polarisation (85 mC m-2) and the pyroelectric coefficient (30 µC m-2 K-1) were enhanced. Thus, annealing plays a substantial role in controlling the crystalline structure of P(VDF-TrFE) films regardless of the choice of solvent. Although, the crystalline structure control is almost independent of the solvent's polarity, the choice of solvent is essential in preparing a smoother film surface. Molecular dynamics of P(VDF-TrFE) are discussed from the observation of two dielectric relaxation processes, ß and γ related to the segmental micro-Brownian and local modes, respectively. The complete ferroelectric polarization reversal caused a reduction in the dielectric polarization and reduced the lattice spacing of the 110/200 planes.

The incidence of congenital syphilis in the United Kingdom: February 2010 to January 2015.

OBJECTIVE: To estimate the incidence of congenital syphilis in the UK. DESIGN: Prospective study. SETTING AND POPULATION: United Kingdom. METHODS: Children born between February 2010 and January 2015 with a suspected diagnosis of congenital syphilis were reported through an active surveillance system. MAIN OUTCOME MEASURES: Number of congenital syphilis cases and incidence. RESULTS: For all years, reported incidence was below the WHO threshold for elimination (<0.5/1000 live births). Seventeen cases (12 male, five female) were identified. About 50% of infants (8/17) were born preterm (<37 weeks' gestation): median birthweight 2000 g (865-3170 g). Clinical presentation varied from asymptomatic to acute disease, including severe anaemia, hepatosplenomegaly, rhinitis, thrombocytopaenia, skeletal damage, and neurosyphilis. One infant was deaf and blind. Median maternal age was 20 years (17-31) at delivery. Where maternal stage of infection was recorded, 6/10 had primary, 3/10 secondary and 1/10 early latent syphilis. Most mothers were white (13/16). Country of birth was recorded for 12 mothers: UK (n = 6), Eastern Europe (n = 3), Middle East (n = 1), and South East Asia (n = 2). The social circumstances of mothers varied and included drug use and sex work. Some experienced difficulty accessing health care. CONCLUSION: The incidence of congenital syphilis is controlled and monitored by healthcare services and related surveillance systems, and is now below the WHO elimination threshold. However, reducing the public health impact of this preventable disease in the UK is highly dependent on the successful implementation of WHO elimination standards across Europe. TWEETABLE ABSTRACT: Congenital syphilis incidence in the UK is at a very low level and well below the WHO elimination threshold.

Orbital implant placement using a computer-aided design and manufacturing (CAD/CAM) stereolithographic surgical template protocol.

Surgical implant placement in the orbital region for the support of a prosthesis is challenging due to the thin orbital rim and proximity to vital structures. This article reports the use of a computer-aided design and manufacturing (CAD/CAM) stereolithographic surgical template protocol for orbital implant placement in four patients, who were followed-up for about 7 years. A total of 11 orbital implants were inserted, eight of these in irradiated bone. No intraoperative complications were noted in any of the patients and the implants were all inserted in the planned positions. The survival rate of implants placed in irradiated bone that received hyperbaric oxygen therapy was 62.5% (5/8). One implant failed in a burns injury patient at 74 months after functional loading. The overall survival of implants in the orbital region and the cumulative survival at 7 years was 63.6%. With regard to skin reactions around the abutments, 85% were grade 0, 13% were grade 1, and 2% were grade 2 according to the Holgers classification. The mean survival time of the first prosthesis was 49 months. High patient satisfaction was achieved with the implant-retained orbital prostheses.

Peri-implant and systemic release of metallic elements following insertion of a mandibular modular endoprosthesis in Macaca fascicularis.

The aim of this study was to assess the release of metal elements from a Ti6Al4V modular endoprosthesis for mandibular reconstruction. Ten monkeys were included, seven of the animals had an endoprosthesis inserted and three served as controls. Mucosa, regional lymph nodes and distant organs, were assessed after the implant had been in place for 12 months, using light (LM) and transmission electron microscopy (TEM) and inductively coupled plasma optical emission spectroscopy (ICP). Blood was also drawn from all animals for elemental analysis using ICP. LM and TEM evaluation showed no detectable metal particles in the mucosa surrounding the endoprosthesis, nor in the regional lymph nodes and distant organs. Blood analysis revealed that titanium and vanadium were detectable in comparable amounts in the test (Ti: 1.63+/-0.54, Va: 0.42+/-0.08) as well as in the control group (Ti: 2.07+/-0.55, Va: 0.37+/-0.07). The amount of aluminum appeared to be higher in the control group (31.77+/-11.67) compared with the test group (20.41+/-9.13), but this difference was not statistically significant. ICP showed that no titanium, vanadium or aluminum was detectable in the mucosa surrounding the endoprosthesis. In addition, no titanium and vanadium were found in the lymph nodes and distant organs using ICP. On the other hand, using ICP, the aluminum content was found to be higher in the right regional lymph nodes and all examined distant organs as compared to the control group (lymph nodes: 11.55+/-22.15 vs. 0.36+/-0.61, lung: 6.24+/-11.28 vs. 1.40+/-2.15, liver: 1.66+/-0.99 vs. 0, kidney: 15.69+/-24.88 vs 0, spleen: 2.75+/-3.09 vs. 0.49+/-0.43). However, only for the kidney and liver the higher amount of aluminum was statistically significant. In conclusion, this study quantified the release of only aluminum in lymph nodes and distant organs, when using a modular endoprosthesis made of Ti-6Al-4V for mandibular reconstruction.

Acute syphilitic posterior placoid chorioretinitis in late latent syphilis.

Diverse manifestations of ocular syphilis may involve any structure in the eye, at any stage of the disease. Posterior uveitis in the form of posterior placoid chorioretinitis has been described in secondary- and tertiary-acquired syphilis. In this case report, we present a 47-year-old man with late latent syphilitic infection and fundoscopic, as well as angiographic findings consistent with acute syphilitic posterior placoid chorioretinitis. To our knowledge this form of patchy multifocal choroiditis has never been described in the latent stage of the disease.

Acute syphilitic interstitial orchitis mimicking testicular malignancy in an HIV-1 infected man diagnosed by Treponema pallidum polymerase chain reaction.

We report a case of acute epididymo-orchitis due to early infectious syphilis, mimicking as testicular malignancy in an undiagnosed HIV-positive individual. He presented with a mass on his testicle and simultaneously had serology consistent with early syphilis. It could not be distinguished from a malignancy, which necessitated urgent orchidectomy. Histology showed endarteritis but no evidence of gummatous involvement. Although treponemes were not detected by staining, the diagnosis was confirmed by the first reported use of Treponema pallidum polymerase chain reaction in a testicular specimen in the UK.

Modular endoprosthesis for mandibular body reconstruction: a clinical, micro-CT and histologic evaluation in eight Macaca fascicularis.

This paper presents the results of an animal experiment, in which a modular endoprosthesis is tested to replace a resected part of the mandible. The prostheses were fixed with polymethacrylate (PMMA) cement into the medullar space of the stumps. Clinical, radiologic, micro-computed tomographic and histologic evaluations were made after 3 and 6 months on four Macaca fascicularis for each implantation time. The prosthesis had not loosened but there were some loose screws that had caused fistulas in three animals. The stems of the modules were stably fixed with PMMA cement, surrounded by a fibrous capsule with inflammatory cells. This capsule was thinner in the 6-month group and showed less inflammatory infiltrate compared with the 3-month group; this was not statistically significant. There was an increase in woven bone surrounding the modules after 6 months. After 3 months of implantation, there was a considerable inflammatory reaction in the soft tissues surrounding the module, which subsided over following 3 months. The results are encouraging, but a longer period of follow-up is required to assess its application in a clinical setting, and some design drawbacks need to be addressed.

Modular endoprosthesis for mandibular reconstruction: a preliminary animal study.

The use of a mandibular modular endoprosthesis after segmental resection of part of the body of the mandible was studied. This preliminary study was carried out on four pigs and four monkeys. The devices were made of a titanium alloy and were cemented in the prepared medullary spaces with polymethylmetacrylate cement. The prosthesis failed in one pig, but in the other animals the prostheses were stable and firmly fixed to the stumps after 3 months. It was concluded that the endoprosthesis has potential in reconstructive surgery of the mandible, but that further studies are necessary to substantiate this claim. Pigs are not suitable for further studies as the medullary space is too large and filled with fat. They are also too big to handle and the variations in size and shape of the mandibles precludes the use of a modular system.

Can chlamydial conjunctivitis result from direct ejaculation into the eye?

The majority of cases of chlamydial conjunctivitis are thought to result from autoinoculation by the patient of infected genital secretions from themselves or their sexual partners. We noted that some patients had developed symptoms following direct ejaculation into the affected eye. We describe four cases of chlamydial conjunctivitis following ejaculation of semen directly into the eye, which have not been previously described. In only one case was chlamydia detected in the genital tract. In three cases, there was no evidence of genital chlamydial infection; the sources of the eye infection being either from infected genital material of their sexual partners transferred by hands to the eyes, or more likely from direct ejaculate inoculation. It is likely that this mode of transmission is underestimated as a history of ejaculation into the conjunctiva is not normally asked for.

Patient-initiated digital photography in Peyronie's disease.

The introduction of digital camera and phone camera without having to develop images by a third party has simplified photography for everyday use. Digital imaging by patients can assist the assessment of medical conditions. We describe four male patients attending our department in whom digital imaging initiated by the patients was deemed to be helpful in supporting the diagnosis and assessing the severity of Peyronie's disease.

Otitis media in adults with chlamydial conjunctivitis.

The aim of this study was to assess the prevalence of otological symptoms in patients with chlamydial conjunctivitis. We report four cases of chlamydial conjunctivitis, in association with otitis media, that were investigated by an otologist.

The Department of Health recurrent-targeted funding for GU medicine clinics: what happened to the funding?

The Department of Health provided two recurrent targeted funding of 5 million pounds sterlings and 3 million pounds sterlings for genitourinary (GU) medicine services in 2003 in response to the increasing waiting times for appointments. The British Association for Sexual Health and HIV conducted a survey to find out if the clinics continued to receive their full allocation, if not, the reasons for it, and the workload change from 2002 to 2004. Out of a total of 91 responders, 78 were from acute trusts and 13 from primary care trusts (PCTs). Of the acute trusts and PCTs, respectively, 67.9% and 76.9% received the full allocation; overall 30.8% did not receive their full allocation. In all, 86% of clinics had increases in their workload and of the 26 clinics with shortfall of funds, 24 (92.3%) still managed to increase the workload. This survey showed that the funding and other measures have increased the workload capacity, and also highlights the continuing problem of many clinics in not receiving their full allocation. Such clinics should be targeted for early review by Medical Foundation for AIDS and Sexual Health with involvement of the Special Health Authorities and PCTs in the current national review of GU services.

Syphilis in adults.

Syphilis is a sexually transmitted disease with protean manifestations resulting from infection by Treponema pallidum. It is systemic early from the outset, the primary pathology being vasculitis. Acquired syphilis can be divided into primary, secondary, latent, and tertiary stages. The infection can also be transmitted vertically resulting in congenital syphilis, and occasionally by blood transfusion and non-sexual contact. Diagnosis is mainly by dark field microscopy in early syphilis and by serological tests. The management in the tropics depends on the diagnostic facilities available: in resource poor countries, primary syphilis is managed syndromically as for anogenital ulcer. The introduction of rapid "desktop" serological tests may simplify and promote widespread screening for syphilis. The mainstay of treatment is with long acting penicillin. Syphilis promotes the transmission of HIV and both infections can simulate and interact with each other. Treponemes may persist despite effective treatment and may have a role in reactivation in immunosuppressed patients. Partner notification, health education, and screening in high risk populations and pregnant women to prevent congenital syphilis are essential aspects in controlling the infection.

Lessons from the syphilis outbreak in homosexual men in east London.

OBJECTIVES: To describe the epidemiology, presentation, and diagnosis of early syphilis in 103 homosexual men in east London. METHODS: A retrospective study using data from KC60 returns, the Health Protection Agency (HPA) enhanced surveillance forms and case notes. RESULTS: 40 cases of primary (PS), 40 of secondary (SS) and 23 of early latent syphilis were identified, 33% co-infected with HIV. 41% had concurrent sexually transmitted infections (STIs). Pain featured in 35% of PS and itch in 13% of rashes. Dark ground microscopy (DGM), performed in 44 of the symptomatic cases, was positive in 37 (84%) allowing early management. Initial syphilis serology was negative in 15/40 (37%) cases of PS. 51% and 49% opted for parenteral and oral treatment, respectively. In 53/103 (51%) cases oral sex was the only risk factor. 86% of infections were UK acquired. Only 4% of contacts were seen. CONCLUSION: This outbreak, reflecting the resurgence of syphilis across the United Kingdom, highlights several important points. Painful chancres and itchy rash are common presentations. DGM is a highly sensitive diagnostic tool. Initial negative serological screening tests are common in PS and sero-surveillance for 3 months is recommended. The high prevalence of concomitant STIs indicates ongoing unprotected sexual intercourse. Oral sex is a significant risk factor and is a distinctly "unsafe" practice. Conventional partner notification is ineffective. Other methods of screening of the at-risk homosexual population are warranted. Continued education is required to reduce STI acquisition in homosexual men.

Dark ground microscopy and treponemal serological tests in the diagnosis of early syphilis.

OBJECTIVES: To evaluate the use of dark ground microscopy (DGM) and treponemal serological tests in the diagnosis of primary (PS) and secondary (SS) syphilis. METHODS: A retrospective case note review of patients with early syphilis who attended our department between January 2001 and December 2002. Data were collected on demographics, results of treponemal serology and DGM. RESULTS: 50 individuals had PS and 36 individuals had SS. DGM was performed in 31/50 (62%) of PS cases and this was positive in 97%. In 17 (34%) cases of PS, treponemal EIA was negative initially. DGM was performed on 13 of these, all of which were positive. Therefore, EIA had a sensitivity of 57% when compared to DGM. In 27 patients where EIA-IgM was performed, this was positive in 22 (81%), of which 12 were EIA negative on initial screening. All SS cases had positive EIA. DGM was performed in 19/36 (52%) of SS cases and was positive in 16/19--that is, a sensitivity of 84% when compared to EIA. The major reason why DGM was not performed in the cases of PS was that herpes was the presumed diagnosis and in SS the rash was attributed to other causes. CONCLUSIONS: DGM is a rapid and sensitive test while EIA takes time for results and is less sensitive in PS. EIA-IgM is a useful adjunct in PS. DGM allows immediate diagnosis, treatment, and partner notification preventing further transmission. Genitourinary medicine clinics should have trained staff to perform DGM on all anogenital ulcers and suspected syphilitic lesions.

Chronic penile oedema secondary to chronic masturbation.

We report the case of a man with proven chlamydial conjunctivitis and urethritis who was found to have asymptomatic chronic penile oedema secondary to masturbation.

Hepatitis B virus infection among Chinese residents in the United Kingdom.

OBJECTIVE: To determine prevalence of hepatitis B virus (HBV) serological markers in Chinese residents in the United Kingdom. METHOD: Retrospective case-controlled study between January 1997 and June 2000 in two genitourinary medicine (GUM) clinics. RESULTS: 117 Chinese and 234 non-Chinese controls were studied. Baseline characteristics except marital status showed no difference. Overall prevalence of HBV serological markers was 35.8% in Chinese, controls 5.5% (p<0.001). Hepatitis B surface antigen (HBsAg) positive carrier rate was 12.8% in Chinese, controls 0.4% (p<0.001); 1.7% of Chinese patients were also hepatitis B e antigen (HBeAg) positive, none in controls. Natural immunity was acquired in 23.0% of Chinese, controls 5.1% (p<0.001). Prevalence of HBV serological markers in UK born Chinese was 6.7%, non-UK born Chinese 40.1% (p<0.011). Only 7.6% of Chinese had a history of previous HBV vaccination. CONCLUSIONS: Prevalence of HBV serological markers among Chinese patients attending two GUM clinics in London was high and only a minority of Chinese had immunisation against HBV. Although the prevalence of HBV markers in UK born Chinese was lower than non-UK born Chinese, they may be at continuous risk of HBV infection. Non-UK born Chinese patients attending GUM services in the United Kingdom should be targeted for screening and vaccination to reduce HBV transmission.