Relating localized nanoparticle resonances to an associated antenna problem

We conceptually unify the description of resonances existing at metallic nanoparticles and optical nanowire antennas. To this end the nanoantenna is treated as a Fabry-Perot resonator with arbitrary semi-nanoparticles forming the terminations. We show that the frequencies of the quasi-static dipolar resonances of these nanoparticles coincide with the frequency where the phase of the complex reflection coefficient of the fundamental propagating plasmon polariton mode at the wire termination amounts to $\pi$. The lowest order Fabry-Perot resonance of the optical wire antenna occurs therefore even for a negligible wire length. This approach can be used either to easily calculate resonance frequencies for arbitrarily shaped nanoparticles or for tuning the resonance of nanoantennas by varying their termination.Comment: Submitted to Phys. Rev.

On the black hole limit of rotating discs and rings

Solutions to Einstein's field equations describing rotating fluid bodies in equilibrium permit parametric (i.e. quasi-stationary) transitions to the extreme Kerr solution (outside the horizon). This has been shown analytically for discs of dust and numerically for ring solutions with various equations of state. From the exterior point of view, this transition can be interpreted as a (quasi) black hole limit. All gravitational multipole moments assume precisely the values of an extremal Kerr black hole in the limit. In the present paper, the way in which the black hole limit is approached is investigated in more detail by means of a parametric Taylor series expansion of the exact solution describing a rigidly rotating disc of dust. Combined with numerical calculations for ring solutions our results indicate an interesting universal behaviour of the multipole moments near the black hole limit.Comment: 18 pages, 4 figures; Dedicated to Gernot Neugebauer on the occasion of his 70th birthda

Increased frequency and nocturia in a middle aged male may not always be due to Benign Prostatic Hypertrophy (BPH): a case report

Primary signet ring cell carcinoma of urinary bladder is a rare type of bladder tumor and carries a very high mortality rate. It may have a clinical presentation similar to common diseases like Benign Prostatic Hypertrophy (BPH) and the management options are extremely limited. We report a case of 58 year old Caucasian male who presented with a 5 month history of increased frequency of urination, nocturia and weight loss without any fever or hematuria. He was found to have an increased creatinine of 2.8 mg/dl and a prostate specific antigen level of 0.18 ng/ml. His azotemia was thought to be secondary to BPH. A foley catheter was initially placed with a plan for outpatient follow up. On removal of the catheter his problems persisted and he returned to the hospital. Diagnostic work up including abdominal ultrasonography, computed tomography (CT) scan, retrograde pyelogram, cystography and cystoscopic biopsies revealed the diagnosis of primary signet ring cell carcinoma of urinary bladder. Although cystectomy was planned, our patient passed away before this could be done

Case Reports1. A Late Presentation of Loeys-Dietz Syndrome: Beware of TGFβ Receptor Mutations in Benign Joint Hypermobility

Background: Thoracic aortic aneurysms (TAA) and dissections are not uncommon causes of sudden death in young adults. Loeys-Dietz syndrome (LDS) is a rare, recently described, autosomal dominant, connective tissue disease characterized by aggressive arterial aneurysms, resulting from mutations in the transforming growth factor beta (TGFβ) receptor genes TGFBR1 and TGFBR2. Mean age at death is 26.1 years, most often due to aortic dissection. We report an unusually late presentation of LDS, diagnosed following elective surgery in a female with a long history of joint hypermobility. Methods: A 51-year-old Caucasian lady complained of chest pain and headache following a dural leak from spinal anaesthesia for an elective ankle arthroscopy. CT scan and echocardiography demonstrated a dilated aortic root and significant aortic regurgitation. MRA demonstrated aortic tortuosity, an infrarenal aortic aneurysm and aneurysms in the left renal and right internal mammary arteries. She underwent aortic root repair and aortic valve replacement. She had a background of long-standing joint pains secondary to hypermobility, easy bruising, unusual fracture susceptibility and mild bronchiectasis. She had one healthy child age 32, after which she suffered a uterine prolapse. Examination revealed mild Marfanoid features. Uvula, skin and ophthalmological examination was normal. Results: Fibrillin-1 testing for Marfan syndrome (MFS) was negative. Detection of a c.1270G > C (p.Gly424Arg) TGFBR2 mutation confirmed the diagnosis of LDS. Losartan was started for vascular protection. Conclusions: LDS is a severe inherited vasculopathy that usually presents in childhood. It is characterized by aortic root dilatation and ascending aneurysms. There is a higher risk of aortic dissection compared with MFS. Clinical features overlap with MFS and Ehlers Danlos syndrome Type IV, but differentiating dysmorphogenic features include ocular hypertelorism, bifid uvula and cleft palate. Echocardiography and MRA or CT scanning from head to pelvis is recommended to establish the extent of vascular involvement. Management involves early surgical intervention, including early valve-sparing aortic root replacement, genetic counselling and close monitoring in pregnancy. Despite being caused by loss of function mutations in either TGFβ receptor, paradoxical activation of TGFβ signalling is seen, suggesting that TGFβ antagonism may confer disease modifying effects similar to those observed in MFS. TGFβ antagonism can be achieved with angiotensin antagonists, such as Losartan, which is able to delay aortic aneurysm development in preclinical models and in patients with MFS. Our case emphasizes the importance of timely recognition of vasculopathy syndromes in patients with hypermobility and the need for early surgical intervention. It also highlights their heterogeneity and the potential for late presentation. Disclosures: The authors have declared no conflicts of interes

Serving scientists in agri-food area by virtual research environments

Agri-food research calls for changes in the practices dealing with data collection, collation, processing and analytics, and publishing thus to fully benefit from and contribute to the Open Science movement. One of the major issues faced by the agri-food researchers is the fragmentation of the 'assets' that can be exploited when performing research tasks, e.g. data of interest are heterogeneous and scattered across several repositories, the tools exploited by modellers are diverse and often rely on local computing environments, the publishing practices are various and rarely aim at making available the 'whole story' with datasets, processes, workflows. This paper presents the AGINFRA+ endeavour to overcome these limitations by providing researchers in three designated communities with Virtual Research Environments facilitating the access to and use of the 'assets' of interest and promote collaboration.</p

Serving Scientists in Agri-food area by Virtual Research Environments

Agri-food research calls for changes in the practices dealing with data collection, collation, processing and analytics, and publishing thus to fully benefit from and contribute to the Open Science movement. One of the major issues faced by the agri-food researchers is the fragmentation of the “assets” that can be exploited when performing research tasks, e.g. data of interest are heterogeneous and scattered across several repositories, the tools exploited by modellers are diverse and often rely on local computing environments, the publishing practices are various and rarely aim at making available the “whole story” with datasets, processes, workflows. This paper presents the AGINFRA+endeavour to overcome these limitations by providing researchers in three designated communities with Virtual Research Environments facilitating the access to and use of the “assets” of interest and promote collaboration