Plasmonic nanoparticle monomers and dimers: From nano-antennas to chiral metamaterials

We review the basic physics behind light interaction with plasmonic nanoparticles. The theoretical foundations of light scattering on one metallic particle (a plasmonic monomer) and two interacting particles (a plasmonic dimer) are systematically investigated. Expressions for effective particle susceptibility (polarizability) are derived, and applications of these results to plasmonic nanoantennas are outlined. In the long-wavelength limit, the effective macroscopic parameters of an array of plasmonic dimers are calculated. These parameters are attributable to an effective medium corresponding to a dilute arrangement of nanoparticles, i.e., a metamaterial where plasmonic monomers or dimers have the function of "meta-atoms". It is shown that planar dimers consisting of rod-like particles generally possess elliptical dichroism and function as atoms for planar chiral metamaterials. The fabricational simplicity of the proposed rod-dimer geometry can be used in the design of more cost-effective chiral metamaterials in the optical domain.Comment: submitted to Appl. Phys.

Book Review

A. Funston, M. Gil & G. Gilmore (Eds). (2014). Strong starts, supportedtransitions and student success. UK: Cambridge Scholars Publishing.Reviewed by Birgit Schreiber

Prostate Cancer in Primary Care

This is the final version of the article. Available from Springer Verlag via the DOI in this record.Prostate cancer is a common malignancy seen worldwide. The incidence has risen in recent decades, mainly fuelled by more widespread use of prostate-specific antigen (PSA) testing, although prostate cancer mortality rates have remained relatively static over that time period. A man's risk of prostate cancer is affected by his age and family history of the disease. Men with prostate cancer generally present symptomatically in primary care settings, although some diagnoses are made in asymptomatic men undergoing opportunistic PSA screening. Symptoms traditionally thought to correlate with prostate cancer include lower urinary tract symptoms (LUTS), such as nocturia and poor urinary stream, erectile dysfunction and visible haematuria. However, there is significant crossover in symptoms between prostate cancer and benign conditions affecting the prostate such as benign prostatic hypertrophy (BPH) and prostatitis, making it very challenging to distinguish between them on the basis of symptoms. The evidence for the performance of PSA in asymptomatic and symptomatic men for the diagnosis of prostate cancer is equivocal. PSA is subject to false positive and false negative results, affecting its clinical utility as a standalone test. Clinicians need to counsel men about the risks and benefits of PSA testing to inform their decision-making. Digital rectal examination (DRE) by primary care clinicians has some evidence to show discrimination between benign and malignant conditions affecting the prostate. Patients referred to secondary care for diagnostic testing for prostate cancer will typically undergo a transrectal or transperineal biopsy, where a number of samples are taken and sent for histological examination. These biopsies are invasive procedures with side effects and a risk of infection and sepsis, and alternative tests such as multiparametric magnetic resonance imaging (mpMRI) are currently being trialled for their accuracy and safety in diagnosing clinically significant prostate cancer

Atomic-scale confinement of optical fields

In the presence of matter there is no fundamental limit preventing confinement of visible light even down to atomic scales. Achieving such confinement and the corresponding intensity enhancement inevitably requires simultaneous control over atomic-scale details of material structures and over the optical modes that such structures support. By means of self-assembly we have obtained side-by-side aligned gold nanorod dimers with robust atomically-defined gaps reaching below 0.5 nm. The existence of atomically-confined light fields in these gaps is demonstrated by observing extreme Coulomb splitting of corresponding symmetric and anti-symmetric dimer eigenmodes of more than 800 meV in white-light scattering experiments. Our results open new perspectives for atomically-resolved spectroscopic imaging, deeply nonlinear optics, ultra-sensing, cavity optomechanics as well as for the realization of novel quantum-optical devices

Multihospital Outbreak of Clostridium difficile Ribotype 027 Infection: Epidemiology and Analysis of Control Measures

Objective. To report a large outbreak of Clostridium difficile infection (CDI; ribotype 027) between June 2007 and August 2008, describe infection control measures, and evaluate the impact of restricting the use of fluoroquinolones in controlling the outbreak. Design. Outbreak investigation in 3 acute care hospitals of the Northern Health and Social Care Trust in Northern Ireland. Interventions. Implementation of a series of CDI control measures that targeted high-risk antibiotic agents (ie, restriction of fluoroquinolones), infection control practices, and environmental hygiene. Results. A total of 318 cases of CDI were identified during the outbreak, which was the result of the interaction between C. difficile ribotype 027 being introduced into the affected hospitals for the first time and other predisposing risk factors (ranging from host factors to suboptimal compliance with antibiotic guidelines and infection control policies). The 30-day all-cause mortality rate was 24.5%; however, CDI was the attributable cause of death for only 2.5% of the infected patients. Time series analysis showed that restricting the use of fluoroquinolones was associated with a significant reduction in the incidence of CDI (coefficient, —0.054; lag time, 4 months; P = .003). Conclusion. These findings provide additional evidence to support the value of antimicrobial stewardship as an essential element of multifaceted interventions to control CDI outbreaks. The present CDI outbreak was ended following the implementation of an action plan improving communication, antibiotic stewardship, infection control practices, environmental hygiene, and surveillanc

Effects of Supplemental Energy and Protein Source on Performance of Steers Grazing Irrigated Corn Residue

Steer calves grazing corn residue (86 d) were assigned to 1 of 5 treatments to evaluate the effects of protein and energy supplements on steer performance. Th e 5 treatments consisted of 1) un-supplemented control (NS), 2) dry rolled corn only (CRN), 3) 89% dry rolled corn/6% molasses/5% urea (C + RDP), 4) 60/40 blend of soy- pass/soybean meal (SP), and 5) dried distillers grains plus solubles (DGS). Supplements were fed to provide equal TDN intake. Average daily gain among treatments was 1.48, 1.32, 0.53, 0.31, and −0.18 lbs. for SP, DGS, C + RDP, CRN, and NS, respectively. Only steers fed SP and DGS produced over- winter gains greater than 1 lb/d, suggesting metabolizable protein requirements must be met for growing calves to utilize residue efficiently

Artificial Insemination of Beef Heifers with Multi-Sire Semen

The study compared pregnancy rates of beef heifers artificially inseminated with multi-sire semen to single-sire semen at ranch 1 and demonstrated pregnancy to multi-sire sexed semen at rand 2. It was hypothesized pregnancy rates resulting from multi-sire semen would be increased compared to single-sire semen. Ranch 1 heifers were inseminated with either single-sire or multi-sire semen and all heifers expressing estrus at ranch 2 were inseminated with multi-sire semen averaged numerically greater pregnancy rate than the average single-sire pregnancy rate and pregnancy outcomes from multi-sire sexed semen exceed previous literature but cannot be directly compared. Despite similar pregnancy results between each single-sire treatment, paternity results suggest sires produce unequal proportions of offspring when their semen is mixed. In summary, producers looking to maximize pregnancy rate to artificial insemination may consider multi-sire insemination but more data is required

Improving the Timely Detection of Bladder and Kidney Cancer in Primary Care

Bladder and kidney cancer are the 10th and 7th most common cancers in the United Kingdom (UK). They present with symptoms that are typically investigated via the same diagnostic pathway. However, diagnosing these cancers can be challenging, especially for kidney cancer, as many of the symptoms are non-specific and occur commonly in patients without cancer. Furthermore, the recognition and evaluation of these symptoms may differ because of the lack of supporting high-quality evidence to inform management, a problem also reflected in currently ambiguous guidelines. The majority of these two cancers are diagnosed following a referral from a general practitioner. In this article, we summarise current UK and United States (US) guidelines for investigating common symptoms of bladder and kidney cancer-visible haematuria, non-visible haematuria and urinary tract infections. Our article aims to support clinicians in recognising and investigating patients with symptoms of possible bladder and kidney cancer in a timely fashion. We discuss challenges during the diagnostic process and possible future interventions for improvement

Risk of fractures in half a million survivors of 20 cancers: a population-based matched cohort study using linked English electronic health records.

BACKGROUND: A history of multiple myeloma, prostate cancer, and breast cancer has been associated with adverse bone health, but associations across a broader range of cancers are unclear. We aimed to compare the risk of any bone fracture and major osteoporotic fractures in survivors of a wide range of cancers versus cancer-free individuals. METHODS: In this population-based matched cohort study, we used electronic health records from the UK Clinical Practice Research Datalink linked to hospital data. We included adults (aged ≥18 years) eligible for linkage, and we restricted the study start to Jan 2, 1998, onwards and applied administrative censoring on Jan 31, 2020. The cancer survivor group included survivors of the 20 most common cancers. Each individual with cancer was matched (age, sex, and general practice) to up to five controls (1:5) who were cancer-free. The primary outcomes were any bone fracture and any major osteoporotic fracture (pelvic, hip, wrist, spine, or proximal humeral fractures) occurring more than 1 year after index date (ie, the diagnosis date of the matched individual with cancer). We used Cox regression models, adjusted for shared risk factors, to estimate associations between cancer survivorship and bone fractures. FINDINGS: 578 160 adults with cancer diagnosed in 1998-2020 were matched to 3 226 404 cancer-free individuals. Crude incidence rates of fractures in cancer survivors ranged between 8·39 cases (95% CI 7·45-9·46) per 1000 person-years for thyroid cancer and 21·62 cases (20·18-23·18) per 1000 person-years for multiple myeloma. Compared with cancer-free individuals, the risk of any bone fracture was increased in 15 of 20 cancers, and of major osteoporotic fractures in 17 of 20 cancers. Effect sizes varied: adjusted hazard ratios (HRs) were largest for multiple myeloma (1·94, 95% CI 1·77-2·13) and prostate cancer (1·43, 1·39-1·47); HRs in the range 1·20-1·50 were seen for stomach, liver, pancreas, lung, breast, kidney, and CNS cancers; smaller associations (HR <1·20) were observed for malignant melanoma, non-Hodgkin lymphoma, leukaemia, and oesophageal, colorectal, and cervical cancers. Increased risks of major osteoporotic fracture were noted most substantially in multiple myeloma (2·25, 1·96-2·58) and CNS (2·12, 1·56-2·87), liver (1·62, 1·01-2·61), prostate (1·60, 1·53-1·67), and lung cancers (1·60, 1·44-1·77). Effect sizes tended to reduce over time since diagnosis but remained elevated for more than 5 years in several cancers, such as multiple myeloma and stomach, lung, breast, prostate, and CNS cancers. INTERPRETATION: Survivors of most types of cancer were at increased risk of bone fracture for several years after cancer, with variation by cancer type. These findings can help to inform mitigation and prevention strategies. FUNDING: Wellcome Trust