Observation of Skewed Electromagnetic Wakefields in an Asymmetric Structure Driven by Flat Electron Bunches

Relativistic charged-particle beams that generate intense longitudinal fields in accelerating structures also inherently couple to transverse modes. The effects of this coupling may lead to beam breakup instability and thus must be countered to preserve beam quality in applications such as linear colliders. Beams with highly asymmetric transverse sizes (flat beams) have been shown to suppress the initial instability in slab-symmetric structures. However, as the coupling to transverse modes remains, this solution serves only to delay instability. In order to understand the hazards of transverse coupling in such a case, we describe here an experiment characterizing the transverse effects on a flat beam, traversing near a planar dielectric lined structure. The measurements reveal the emergence of a previously unobserved skew-quadrupolelike interaction when the beam is canted transversely, which is not present when the flat beam travels parallel to the dielectric surface. We deploy a multipole field fitting algorithm to reconstruct the projected transverse wakefields from the data. We generate the effective kick vector map using a simple two-particle theoretical model, with particle-in-cell simulations used to provide further insight for realistic particle distributions.

A highly virulent variant of HIV-1 circulating in the Netherlands

We discovered a highly virulent variant of subtype-B HIV-1 in the Netherlands. One hundred nine individuals with this variant had a 0.54 to 0.74 log₁₀ increase (i.e., a ~3.5-fold to 5.5-fold increase) in viral load compared with, and exhibited CD4 cell decline twice as fast as, 6604 individuals with other subtype-B strains. Without treatment, advanced HIV-CD4 cell counts below 350 cells per cubic millimeter, with long-term clinical consequences-is expected to be reached, on average, 9 months after diagnosis for individuals in their thirties with this variant. Age, sex, suspected mode of transmission, and place of birth for the aforementioned 109 individuals were typical for HIV-positive people in the Netherlands, which suggests that the increased virulence is attributable to the viral strain. Genetic sequence analysis suggests that this variant arose in the 1990s from de novo mutation, not recombination, with increased transmissibility and an unfamiliar molecular mechanism of virulence.

Coping With Human-Cat Interactions Beyond the Limits of Domesticity: Moral Pluralism in the Management of Cats and Wildlife

Although human interactions with cats are often even typically analyzed in the context of domesticity, with a focus on what sorts of interactions might make both people and cats "happy at home," a large number of cats in the world live, for one reason or another, beyond the bounds of domesticity. Human interactions with these more or less free-living cats raise deeply controversial questions about how both the cats and the people they interact with should be sensibly managed, and about the moral imperatives that ought to guide the management of their interactions through the laws and public policies regulating both human interactions with pets and with wildlife. We review the geography of human interactions with cats living beyond the bounds of domesticity. We acknowledge the contributions made to ideas about how to manage cats by the animal protection movement. We review the tensions that have emerged over time between advocates for the eradication of free-living cats, because of the impacts they have on native wildlife species, and those who have imagined alternatives to eradication, most notably one or another variant of trap-neuter-return (TNR). The conflict over how best to deal with cats living beyond the bounds of domesticity and their wildlife impacts raises the prospect of stalemate, and we canvass and critique possibilities for moving beyond that stalemate.

Respiratory samples to diagnose tuberculosis in the absence of chest x-ray abnormalities

BACKGROUND

The World Health Organisation states that the chest x-ray (CXR) has a 'high sensitivity for pulmonary tuberculosis (TB)' [1] and as such, is relied on worldwide as the cornerstone of screening for active pulmonary TB (pTB).

METHOD

This is a retrospective analysis of plain chest radiographs and microbiological yield in all patients who were diagnosed with pTB or intra-thoracic nodal tuberculosis (ITLN) in two London NHS Trusts.

RESULTS

Between 2011 and 2017 8% of those diagnosed with pTB and 32% with ITLN TB had normal CXR appearances in the 6 weeks preceding diagnosis.

DISCUSSION

Pulmomary TB was diagnosed in an additional 51 people based on CT scan and 43 people based on respiratory samples. ITLN TB was also diagnosed in a further 20 people using CT but only an extra 3 people from standard respiratory sampling. Our data suggests that CT imaging and respiratory samples should be sent on all suspected cases of pTB and ITLN TB even if the CXR is normal.

Neuroinvasive West Nile virus in a traveller from the United States to England

Infections with West Nile virus (WNV) are emerging as a significant risk in North America and Europe; however, imported cases to the UK are still rarely seen. We report a case of neuroinvasive WNV in a traveller from the USA to the UK.

Predicting drug-induced liver injury from anti-tuberculous medications by early monitoring of liver tests

OBJECTIVE

Tuberculosis Drug Induced Liver Injury (TB-DILI) is a common and potentially severe complication associated with anti-tuberculous treatment (ATT). Optimal liver test monitoring for standard TB medication has not been established. We describe the predictive value of pre-treatment liver tests (LTs) and at 2-weeks after initiation of ATT for the detection of TB-DILI.

METHODS

Patients initiating ATT were monitored with routine LTs pre-treatment and after 2-weeks. Logistic regression models were constructed to retrospectively identify pre-treatment variables associated with 'late' TB-DILI (>2 weeks after treatment initiation) and whether pre-treatment and 2-week alanine aminotransferase (ALT) levels could predict late TB-DILI.

RESULTS

1247 patients with active tuberculosis managed at 5 sites across north west London between January 2015 and December 2018 were monitored with routine LTs. 103 cases (8.3%) of ATT-associated DILI were diagnosed. 60 cases (58.3%) of TB-DILI occurred later than 2-weeks. The risk of late TB-DILI was 2.2-fold greater for every 30 U/L increment in ALT pre-treatment (OR 2.16, 95% CI 1.38-3.29 p<0.001) and 2.1-fold greater for every 30 U/L increment in ALT gradient at 2-weeks (OR 2.06, 95% CI 1.52-2.76 p<0.001).

CONCLUSION

Routine 2-week LTs capture early TB-DILI and may be valuable in predicting late TB-DILI in patients on ATT.

Single Shot Characterization of High Transformer Ratio Wakefields in Nonlinear Plasma Acceleration

Plasma wakefields can enable very high accelerating gradients for frontier high energy particle accelerators, in excess of 10  GeV/m. To overcome limits on single stage acceleration, specially shaped drive beams can be used in both linear and nonlinear plasma wakefield accelerators (PWFA), to increase the transformer ratio, implying that the drive beam deceleration is minimized relative to acceleration obtained in the wake. In this Letter, we report the results of a nonlinear PWFA, high transformer ratio experiment using high-charge, longitudinally asymmetric drive beams in a plasma cell. An emittance exchange process is used to generate variable drive current profiles, in conjunction with a long (multiple plasma wavelength) witness beam. The witness beam is energy modulated by the wakefield, yielding a response that contains detailed spectral information in a single-shot measurement. Using these methods, we generate a variety of beam profiles and characterize the wakefields, directly observing transformer ratios up to R=7.8. Furthermore, a spectrally based reconstruction technique, validated by 3D particle-in-cell simulations, is introduced to obtain the drive beam current profile from the decelerating wake data.

Recurrent spondylodiscitis secondary to hallux osteomyelitis

Foot infections are the commonest complication of diabetes mellitus requiring hospitalisation. Despite local osteomyelitis being the most frequent sequel of a diabetic foot infection, there is emerging evidence to suggest that local disease may lead to distant infections. In this report we present a case of recurrent thoracic spine spondylodiscitis due to left hallux osteomyelitis in a man with type 2 diabetes. This case illustrates the importance of considering spondylodiscitis as a differential diagnosis in patients presenting with diabetic foot infection and complaining of acute severe back pain.

Computed tomography colonography: a retrospective analysis of outcomes of 2 years experience in a district general hospital

BACKGROUND

Colonoscopy is the gold-standard investigation for direct luminal visualization of the large bowel. Studies have shown the efficacy of computed tomography colonography (CTC) is equivalent to colonoscopy in both cancer and polyp detection.

METHODS

A retrospective review of patients undergoing CTC from January 2013 to October 2014 was performed. Patient demographics, indication for investigation, computed tomography findings, optical colonoscopy findings and histology results were recorded.

RESULTS

Seven hundred and fifty-eight CTC were performed. Three hundred and seventeen patients were male (42%) and 441 (58%) were female. Endoscopy was advised in 209 cases. One hundred and twenty (16%) were deemed suspicious for cancer of whom 96 (80%) had optical colonoscopy. A total of 12 colorectal cancers were detected. Potential polyps were noted in 58 cases (8%). Forty-four patients underwent endoscopy (75%) and 17 polyps confirmed (38%). Two patients had foci of invasive cancer histologically. Significant extracolonic findings were identified in 60%, including five cases of gastric carcinomas. The most common other findings were gallstones and hernias.

CONCLUSION

The rate of colorectal cancer detection in this study was 2%. The rate of biopsy proven cancer was 10% following a suspicious colonogram. Endoscopic correlation was not obtained in 20% of cases of radiological suspicion. CTC is as efficacious as optical colonoscopy for colorectal cancer and polyp detection.

Standardised Sleeve Gastrectomy Without Reinforcement

Background and Objectives:

Laparoscopic sleeve gastrectomy (LSG) has some unique complications, the most concerning of which is sleeve leak. Staple line reinforcement (SLR) has been suggested as a means of decreasing the risk of sleeve leak, but it increases the cost. However, there is little in the literature regarding the effect of standardized operative technique in reducing the complications and improving the outcomes in LSG. We sought to demonstrate that standardization of the operative procedure and perioperative care is the key to an excellent 30-day outcome and that SLR is not necessary to ensure a negligible staple line leak and bleeding rate.

Methods:

A prospectively maintained database was analyzed to identify 303 consecutive patients undergoing LSG between July 2010 and November 2017. Data on patient demographics, length of hospital stay, conversion to open surgery, perioperative complications, and mortality were analyzed. Standardized operative technique and postoperative protocol were followed in all cases. SLR was not used in any case.

Results:

Among 303 cases, there were 15 complications (5%), 5 (1.7%) of which were severe (Clavien-Dindo grade ≥3a). There were no conversions to open procedure, no staple line leaks, and no inpatient deaths in the cohort. No patient was readmitted with an early stricture.

Conclusions:

The use of a standardized operative and postoperative protocol led to an excellent early outcome in our LSG cases. Standardization may act to obviate the need for routine SLR techniques which are associated with a significant financial cost to both patient and hospital.

Oesophageal adenocarcinoma following gastric band surgery in two patients

Oesophageal adenocarcinoma following gastric band surgery has only been reported three times previously. The incidence is higher in morbidly obese patients, and its pathogenesis is correlated to reflux-induced microenvironmental changes. Bariatric surgery is transformative and its potential benefit for a substantial population is huge. Although no causal relationship with bariatric procedures has been evidenced to date, symptoms of adenocarcinoma—particularly anorexia, weight loss and dysphagia—can easily be overshadowed by alterations in eating patterns associated with weight-loss procedures. We report two cases of oesophageal adenocarcinoma in patients who had undergone a gastric banding procedure, and invite readers to consider the role that pre- and post-operative acid reflux dynamics may have precipitating neoplastic disease, and how endoscopic surveillance may play a role in prevention.

Prognostic value of interferon-γ release assays and tuberculin skin test in predicting the development of active tuberculosis (UK PREDICT TB): a prospective cohort study

BACKGROUND

Tackling tuberculosis requires testing and treatment of latent tuberculosis in high-risk groups. The aim of this study was to estimate the predictive values of the tuberculin skin test (TST) and two interferon-γ release assays (IGRAs) for the development of active tuberculosis in high-risk groups-ie, people in recent contact with active tuberculosis cases and from high-burden countries.

METHOD

In this prospective cohort study, we recruited participants from 54 centres (eg, clinics, community settings) in London, Birmingham, and Leicester in the UK. Participants were eligible if they were aged 16 years or older and at high risk for latent tuberculosis infection (ie, recent contact with someone with active tuberculosis [contacts] or a migrant who had arrived in the UK in the past 5 years from-or who frequently travelled to-a country with a high burden of tuberculosis [migrants]). Exclusion criteria included prevalent cases of tuberculosis, and participants who were treated for latent tuberculosis after a positive test result in this study. Each participant received three tests (QuantiFERON-TB Gold-In Tube, T-SPOT.TB, and a Mantoux TST). A positive TST result was reported using three thresholds: 5 mm (TST-5), 10 mm (TST-10), and greater than 5 mm in BCG-naive or 15 mm in BCG-vaccinated (TST-15) participants. Participants were followed up from recruitment to development of tuberculosis or censoring. Incident tuberculosis cases were identified by national tuberculosis databases, telephone interview, and review of medical notes. Our primary objective was to estimate the prognostic value of IGRAs compared with TST, assessed by the ratio of incidence rate ratios and predictive values for tuberculosis development. The study was registered with ClinicalTrials.gov, NCT01162265, and is now complete.

FINDINGS

Between May 4, 2010, and June 1, 2015, 10 045 people were recruited, of whom 9610 were eligible for inclusion. Of this cohort, 4861 (50·6%) were contacts and 4749 (49·4%) were migrants. Participants were followed up for a median of 2·9 years (range 21 days to 5·9 years). 97 (1·0%) of 9610 participants developed active tuberculosis (77 [1·2%] of 6380 with results for all three tests). In all tests, annual incidence of tuberculosis was very low in those who tested negatively (ranging from 1·2 per 1000 person-years, 95% CI 0·6-2·0 for TST-5 to 1·9 per 1000 person-years, 95% CI 1·3-2·7, for QuantiFERON-TB Gold In-Tube). Annual incidence in participants who tested positively were highest for T-SPOT.TB (13·2 per 1000 person-years, 95% CI 9·9-17·4), TST-15 (11·1 per 1000 person-years, 8·3-14·6), and QuantiFERON-TB Gold In-Tube (10·1 per 1000 person-years, 7·4-13·4). Positive results for these tests were significantly better predictors of progression than TST-10 and TST-5 (eg, ratio of test positivity rates in those progressing to tuberculosis compared with those not progressing T-SPOT.TB vs TST-5: 1·99, 95% CI 1·68-2·34; p<0·0001). However, TST-5 identified a higher proportion of participants who progressed to active tuberculosis (64 [83%] of 77 tested) than all other tests and TST thresholds (≤75%).

INTERPRETATION

IGRA-based or BCG-stratified TST strategies appear most suited to screening for potential disease progression among high-risk groups. Further work will be needed to assess country-specific cost-effectiveness of each screening test, and in the absence of highly specific diagnostic tests, cheap non-toxic treatments need to be developed that could be given to larger groups of people at potential risk.

FUNDING

National Institute for Health Research Health Technology Assessment Programme 08-68-01.

Bariatric fellowship positively influences early outcomes for laparoscopic Roux-en-Y gastric bypass surgery over seven years of independent practice

Introduction Laparoscopic Roux-en-Y gastric bypass (LRYGB) is technically demanding and has an associated learning curve. We published previously that bariatric fellowship reduces the learning curve of primary LRYGB and improves patient outcomes after one year of independent practice. However, the long-term effect of fellowship is unknown. We therefore aimed to compare the 30-day outcomes of LRYGB between the first year of a surgeon's independent practice with the subsequent six years. Materials and methods A prospective database of patients undergoing primary LRYGB under a single surgeon from March 2010 until February 2017 was analysed. Two groups were studied: first year (< 1 year) and the subsequent six years (≥ 1 year) of independent practice. Patient demographics, length of hospital stay, conversion to open surgery, perioperative complications and mortality were compared. Results Among 279 eligible patients, 74 (26.5%) were in the < 1 year group and 205 (73.5%) in ≥ 1 year group. The preoperative risk scores, American Society of Anesthesiologists (ASA) grade, P = 0.00; obesity surgery mortality risk score (OS-MRS), P = 0.04) were significantly higher in ≥ 1 year group. There was no significant difference in perioperative outcomes (length of stay, P = 0.38; total complications, P = 0.20; readmissions, P = 1.00; reoperations, P = 0.60) between the two groups. Conclusions Bariatric fellowship reduces the learning curve for LRYGB and helps to achieve excellent outcomes in the first and subsequent years of independent practice. The higher risk profile of ≥ 1 year group did not equate to an increase in complications, suggesting that experience and standardisation may help in handling complex cases. To our knowledge, this represents the only such study in the literature.

Enhancing Resources for Smoking Cessation through Community Intervention: COMMIT as a Prototype

Of the 17 million smokers in North America who attempt to quit smoking each year, fewer than one in ten succeed [1, 2]. How can communities improve smokers' chances of quitting? The National Cancer Institute addresses this question through COMMIT, the Community Intervention Trial for Smoking Cessation. COMMIT is the largest smoking intervention trial in the world, involving over 2 million people in twenty-two North American communities. The study protocol requires that the implementation of mandated interventions in each community be managed by a Community Board and at least four task forces (Health Care, Worksites and Organizations, Cessation Resources, and Public Education, including Media and Youth). Three required and three optional interventions in the COMMIT protocol relate to the availability of cessation resources and services. The Cessation Resources Task Force, composed of community volunteers, supervises implementation of these interventions at each site. The activities of each task force are integrated with the others in a community action plan. How COMMIT activities enhance the utilization of cessation resources and services and how these services fit into a community intervention is the subject of this article. Descriptions of the study design and evaluation plan, and of the community mobilization process are presented elsewhere [3, 4].

Metastatic endophthalmitis

Endophthalmitis carries a poor visual prognosis for patients and can be a potentially blinding condition that may result in loss of the eye. Early diagnosis and prompt treatment are imperative to save the eye. Delay in diagnosis affects visual prognosis and therefore doctors should be aware of the presenting features of endophthalmitis. Urgent ophthalmic referral is advised as soon as a diagnosis is suspected.

Endogenous Candida endophthalmitis

Intraocular Candida infections, although uncommon, represent an important clinical problem owing to the potential for visual loss, which can be bilateral. Candida chorioretinitis and endophthalmitis are complications of systemic candidiasis with extension of the fungal pathogens to the uvea and retina. Early diagnosis and prompt management significantly affect the visual prognosis for these patients. This review evaluates the current literature on Candida endophthalmitis and includes discussion on presentation, diagnosis and management strategies. New systemic and intravitreal antifungal agents are also reviewed in the context of the management of intraocular fungal infection.

Fever, headache, and visual blurring in a 17-year-old woman

A fascinating case, with much to learn about diagnosis and treatment of patients with abnormal CSF results. After learning from the case, take our online quiz

The challenge of mastitis

The process of lactation and feeding, referred to by some as the final stage of labour is remarkably successful. This phase of infant care has been subjected to considerable evolutionary pressure since the earliest mammals, reptiles and birds diversified. It has allowed thousands of species to occupy a vast range of ecological niches. Yet a significant complication of breast feeding remains inflammation of the lactating tissue: the pathology of mastitis. Mastitis rarely develops outside lactation, although it may affect individuals at any age in relation to congenital lesions such as duct ectasia, chronic disseminated infections such as tuberculosis, or during granulomatous, autoimmune or malignant processes. The immunology and consequences of mastitis as well as its impact on vertical transmission of infection require careful examination.

HIV/AIDS and the eye

The type of ocular involvement in the patient with human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) depends on the level of immune function and systemic diseases present. Although the prognosis for patients with HIV/AIDS has changed dramatically with the introduction of antiretroviral therapy, infections involving the retina, such as toxoplasmosis, herpes simplex and herpes zoster (HZV), still occur although opportunistic infections such as cytomegalovirus (CMV) retinitis are much less common except in patients who present late in the course of the disease (Jabs and Bartlett, 1997; Jabs et al, 2002).

Striae formation in two HIV-positive persons receiving protease inhibitors

Steroidal side effects such as "buffalo hump" and visceral abdominal fat accumulation have been reported in association with protease inhibitors. We report two cases of severe disfiguring striae formation in patients with HIV who recently started indinavir therapy. These changes occurred within 3 months of starting treatment.

Neurodegeneration induced by MoMuLV-ts1 and increased expression of Fas and TNF-alpha in the central nervous system

Infection of neonatal mice with ts1, the neuropathogenic mutant of the Moloney murine leukemia virus, results in motor neuronal death in the brainstem and the spinal cord, with gliosis and demyelination, but no inflammatory cell infiltration into the CNS. To evaluate the possible mechanism(s) of ts1-induced neuropathogenesis, we measured CNS expression of cytokines and cell death-related genes in ts1-infected mice with neurological signs and compared with control uninfected mice. In the brainstem, the expression of Fas and tumor necrosis factor alpha (TNF-alpha) was increased in the ts1-infected mice. Both TNF-alpha and Fas were detected in astrocytes, and Fas was also detected in neurons in the brainstem. Some TNF-alpha-immunolabeled cells also appeared to be microglial cells. Most Fas-positive cells, including astrocytes and neurons, showed cytoplasmic vacuolization and other degenerative changes. In addition, Fas ligand-immunolabeled cells were also detected in sites where spongiform degeneration occurred. This study suggests that neural cell death in ts1-induced neurodegeneration is likely due to Fas- and TNF-alpha-mediated cell death mechanisms.

The American Stop Smoking Intervention Study for cancer prevention: an overview

The American Stop Smoking Intervention Study (ASSIST) is a programme to implement proven interventions in 17 states across the United States. ASSIST applies all that we have learned in 10 years of research on tobacco use prevention and control. The goal of this seven-year project is to reduce the prevalence of smoking and cigarette consumption in the ASSIST states. The scientific basis for ASSIST is described, followed by a general description of the project and its current status in the 17 targeted states.

Promoting worksite smoking control policies and actions: the Community Intervention Trial for Smoking Cessation (COMMIT) experience. The COMMIT Research Group

BACKGROUND

As an important aspect of the COMMIT trial, worksite smoking-control consultations and supports were provided to employers in 11 diverse, moderate-sized communities. After a 4-year intervention period (1989-1992), impacts on worksite policies, support resources for smokers, and employee perceptions were assessed in these communities and in 11 matched Comparison communities.

METHODS

Data from two surveys are reported here. In each of the 22 COMMIT communities, a sample of worksites within each of four size strata were surveyed to determine worksite policies, activities, and resources regarding smoking. Data from employees were obtained from independent community-wide surveys of community residents.

RESULTS

Overall, 44% of the worksites surveyed reported having smoke-free policies, with no differences between Intervention and Comparison communities. Thirty-seven percent of Intervention community work-sites reported offering smoking cessation resources or assistance for employees during the period of the study, compared to 31% of Comparison community worksites (P = 0.04). Employees in Intervention communities, relative to those in Comparison communities, reported greater awareness of stop-smoking resources, but equivalent increases in worksite smoking bans.

CONCLUSION

Although the level of worksite smoking-cessation activities was higher in Intervention than in Comparison communities, there remains a substantial need to increase the level of such activities and to integrate such activities with restrictive smoking policies.

Chickenpox pneumonia: experience with antiviral treatment

Of 13 patients with chickenpox pneumonia (12 of them adults) treated during 1979-87, 10 received antiviral drugs--nine acyclovir and one vidarabine. Three died despite intensive treatment. Serious secondary infections occurred in six cases. There were no clear indications that antiviral treatment altered the natural history of the condition. Acyclovir may at present be used too late in the course of chickenpox pneumonia to alter its outcome.