Stellar

The ^{36}Ar(n,γ)^{37}Ar (t_{1/2}=35 d) and ^{38}Ar(n,γ)^{39}Ar (269 yr) reactions were studied for the first time with a quasi-Maxwellian (kT∼47 keV) neutron flux for Maxwellian average cross section (MACS) measurements at stellar energies. Gas samples were irradiated at the high-intensity Soreq applied research accelerator facility-liquid-lithium target neutron source and the ^{37}Ar/^{36}Ar and ^{39}Ar/^{38}Ar ratios in the activated samples were determined by accelerator mass spectrometry at the ATLAS facility (Argonne National Laboratory). The ^{37}Ar activity was also measured by low-level counting at the University of Bern. Experimental MACS of ^{36}Ar and ^{38}Ar, corrected to the standard 30 keV thermal energy, are 1.9(3) and 1.3(2) mb, respectively, differing from the theoretical and evaluated values published to date by up to an order of magnitude. The neutron-capture cross sections of ^{36,38}Ar are relevant to the stellar nucleosynthesis of light neutron-rich nuclides; the two experimental values are shown to affect the calculated mass fraction of nuclides in the region A=36-48 during the weak s process. The new production cross sections have implications also for the use of ^{37}Ar and ^{39}Ar as environmental tracers in the atmosphere and hydrosphere.

Probing the Single-Particle Character of Rotational States in

A beam containing a substantial component of both the J^{π}=5^{+}, T_{1/2}=162 ns isomeric state of ^{18}F and its 1^{+}, 109.77-min ground state is utilized to study members of the ground-state rotational band in ^{19}F through the neutron transfer reaction (d,p) in inverse kinematics. The resulting spectroscopic strengths confirm the single-particle nature of the 13/2^{+} band-terminating state. The agreement between shell-model calculations using an interaction constructed within the sd shell, and our experimental results reinforces the idea of a single-particle-collective duality in the descriptions of the structure of atomic nuclei.

Superallowed α Decay to Doubly Magic

We report the first observation of the ^{108}Xe→^{104}Te→^{100}Sn α-decay chain. The α emitters, ^{108}Xe [E_{α}=4.4(2) MeV, T_{1/2}=58_{-23}^{+106} µs] and ^{104}Te [E_{α}=4.9(2) MeV, T_{1/2}<18 ns], decaying into doubly magic ^{100}Sn were produced using a fusion-evaporation reaction ^{54}Fe(^{58}Ni,4n)^{108}Xe, and identified with a recoil mass separator and an implantation-decay correlation technique. This is the first time α radioactivity has been observed to a heavy self-conjugate nucleus. A previous benchmark for study of this fundamental decay mode has been the decay of ^{212}Po into doubly magic ^{208}Pb. Enhanced proton-neutron interactions in the N=Z parent nuclei may result in superallowed α decays with reduced α-decay widths significantly greater than that for ^{212}Po. From the decay chain, we deduce that the α-reduced width for ^{108}Xe or ^{104}Te is more than a factor of 5 larger than that for ^{212}Po.

Study of the

The existence of ^{26}Al (t_{1/2}=7.17×10^{5} yr) in the interstellar medium provides a direct confirmation of ongoing nucleosynthesis in the Galaxy. The presence of a low-lying 0^{+} isomer (^{26}Al^{m}), however, severely complicates the astrophysical calculations. We present for the first time a study of the ^{26}Al^{m}(d,p)^{27}Al reaction using an isomeric ^{26}Al beam. The selectivity of this reaction allowed the study of ℓ=0 transfers to T=1/2, and T=3/2 states in ^{27}Al. Mirror symmetry arguments were then used to constrain the ^{26}Al^{m}(p,γ)^{27}Si reaction rate and provide an experimentally determined upper limit of the rate for the destruction of isomeric ^{26}Al via radiative proton capture reactions, which is expected to dominate the destruction path of ^{26}Al^{m} in asymptotic giant branch stars, classical novae, and core collapse supernovae.

Hearing loss in survivors of childhood head and neck rhabdomyosarcoma: a long-term follow-up study.

OBJECTIVES: To determine the hearing status of survivors treated for head and neck rhabdomyosarcoma (HNRMS) at long-term follow-up. DESIGN: Cross-sectional long-term follow-up study. SETTING: Tertiary comprehensive cancer centre. PARTICIPANTS: Survivors treated for HNRMS during childhood in two concurrent cohorts; survivors in London had been treated with external beam radiotherapy (EBRT-based local therapy); survivors in Amsterdam were treated with AMORE (Ablative surgery, MOuld technique afterloading brachytherapy and surgical REconstruction) if feasible, otherwise EBRT (AMORE-based local therapy). MAIN OUTCOME MEASURES: We assessed hearing status of HNRMS survivors at long-term follow-up. Hearing thresholds were obtained by pure-tone audiometry. METHODS: We assessed the hearing thresholds, the number of patients with clinically relevant hearing loss and hearing impairment graded according to the Common Terminology Criteria for Adverse Events version 4.0 (CTCAEv4) and Boston criteria. Furthermore, we compared hearing loss between survivors treated with EBRT-based local therapy (London) and AMORE-based local therapy (Amsterdam). RESULTS: Seventy-three survivors were included (median follow-up 11 years). We found clinically relevant hearing loss at speech frequencies in 19% of survivors. Multivariable analysis showed that survivors treated with EBRT-based treatment and those with parameningeal tumours had significantly more hearing impairment, compared to survivors treated with AMORE-based treatment and non-parameningeal tumours. CONCLUSIONS: One in five survivors of HNRMS developed clinically relevant hearing loss. AMORE-based treatment resulted in less hearing loss compared to EBRT-based treatment. As hearing loss was highly prevalent and also occurred in survivors with orbital primaries, we recommend systematic audiological follow-up in all HNRMS survivors.

First Direct Measurement of (12)C((12)C,n)(23)Mg at Stellar Energies.

Neutrons produced by the carbon fusion reaction (12)C((12)C,n)(23)Mg play an important role in stellar nucleosynthesis. However, past studies have shown large discrepancies between experimental data and theory, leading to an uncertain cross section extrapolation at astrophysical energies. We present the first direct measurement that extends deep into the astrophysical energy range along with a new and improved extrapolation technique based on experimental data from the mirror reaction (12)C((12)C,p)(23)Na. The new reaction rate has been determined with a well-defined uncertainty that exceeds the precision required by astrophysics models. Using our constrained rate, we find that (12)C((12)C,n)(23)Mg is crucial to the production of Na and Al in pop-III pair instability supernovae. It also plays a nonnegligible role in the production of weak s-process elements, as well as in the production of the important galactic γ-ray emitter (60)Fe.

Consent for functional endoscopic sinus surgery: are we complying with the law?

OBJECTIVE: To assess the current standard of consent for functional endoscopic sinus surgery and determine whether it complies with the law following the Montgomery ruling. METHODS: Ten complications following functional endoscopic sinus surgery were identified as common or serious from a literature search. Using questionnaires, ENT surgeons were asked which of these complications they discussed with patients, and patients were asked how seriously they regarded those risks using a five-point Likert scale. RESULTS: Consent practice from 21 ENT surgeons and data from 103 patients were analysed. The 'reasonable patient' would expect to be consented for all risks, except for pain, and scarring or adhesions. Most ENT surgeons would routinely discuss all risks that were considered significant, except for facial paraesthesia (29 per cent) and damage to the nasolacrimal duct (24 per cent). A negative change in sense of smell was not mentioned by 29 per cent of surgeons. CONCLUSION: This paper demonstrates that the current consent process for functional endoscopic sinus surgery is likely to be substandard medicolegally.

Renal autotransplantation as savior in hybrid surgery for aortic aneurysm repair.

Renal autotransplantation is a safe and effective procedure to reconstruct the urinary tract. The current indications for autotransplantation include renal vascular disease, severe ureteral damage, tumours of the kidney and ureter, complex nephrolithiasis and retroperitoneal fibrosis. We report a rare case where we had to perform renal autotransplantation along with hybrid surgery for aortic aneurysm repair. To our knowledge, this is the first case report of its kind for this specific condition.

Ipsilateral ureteroureterostomy: does function of the obstructed moiety matter?

PURPOSE: Upper pole nephrectomy has been the traditional surgical management of children with poorly functioning upper pole moieties in duplex renal collecting systems having ureteral ectopia and ureterocele. However, ablative surgery confers a risk of functional loss to the remnant moiety due to vasospasm or vascular injury. It was hypothesized that ipsilateral ureteroureterostomy (IUU) is a safe and feasible approach for the management of these patients and that residual function in the obstructed upper pole does not affect surgical outcomes. MATERIALS AND METHODS: All patients with duplex systems who underwent IUU between 2010 and 2016 were retrospectively reviewed. Patients were sorted into two groups based on pre-operative imaging: those having <10% upper pole moiety function (UPMF) and those having ≥ 10% UPMF. Outcomes assessed were postoperative complications (Clavien-Dindo classification), need for secondary surgery, and radiological outcomes. RESULTS: The study cohort comprised 53 children with ectopia or ureterocele affecting the upper pole in a duplex system, 21 with UPMF <10% (median function 0% and median age 1.49 years) and 32 with UPMF ≥ 10% (median function 15% and median age 0.91 years). Median follow-up was 27.4 months and 27.6 months. In both the groups, prenatal hydronephrosis was the most common presentation (57% and 56%, respectively; p = 0.18) followed by urinary tract infection. Mann-Whitney U test comparing the two groups revealed no significant differences in any of the outcomes assessed. No patient required secondary surgery. CONCLUSION: Ipsilateral ureteroureterostomy is a safe, definitive surgical intervention that preserves the renal architecture in children with duplex collecting systems regardless of upper pole function.

Outcome of Dorsal Onlay Buccal Mucosa Substitution Urethroplasty in Long Strictures of Anterior Urethra.

BACKGROUND: The surgical treatment of adult anterior urethral strictures is constantly evolving. Controversy exists over the best means of reconstructing the anterior urethra. METHODS: Twelve patients underwent buccal mucosal urethroplasty for long segment anterior urethral stricture between 2003 and 2005 . Eleven patients with a salvageable urethral plate were treated with one stage dorsal onlay urethroplasty, using a perineal or circumcoronal incision. One patient with a severely scarred urethral plate underwent two-stage urethroplasty. RESULTS: At a mean follow up of 14.2 months (range 2 to 26) one (8.3%) patient had short recurrent stricture, which was treated with optical urethrotomy. The mean maximal urine flow rate improved from 8.3 ml/sec to 18.1 ml/sec after the surgery. There were no donor site complications. All patients had a normal slit like meatus and none had chordee or erectile dysfunction. CONCLUSION: In long stricture of anterior urethra, dorsal onlay buccal mucosa urethroplasty provides excellent intermediate term results with a normal, wide caliber urethra.

A Comparative Study of Laparoscopic with Conventional Open Donor Nephrectomy in Renal Transplantation.

BACKGROUND: Laparoscopic donor nephrectomy (LDN) has been gaining popularity among kidney donors. There have been concerns about the safety and efficacy of the procedure as compared to open donor nephrectomy (ODN). We compare our results on LDN with ODN. METHODS: We retrospectively analysed our data of LDN and ODN. Duration of surgery, blood loss, period of hospitalisation, per oral intake and analgesic requirements. RESULT: 22 LDNs were done, the operation time ranged from 220-300 minutes, and blood loss from 100-150ml. In the first 10 laparoscopic operations four cases required conversion to open surgical dissection. Only one case was converted to open surgery in the subsequent 12 laparoscopic cases. Oral intake was started on the first postoperative day. Analgesic requirement in laparoscopy cases was less. Patients were mobilised on the first day after surgery. Patients were discharged by seventh day. There was no significant difference in the functioning of the graft after revascularisation in the recipient. CONCLUSION: Laparoscopic donor nephrectomy is a safe and effective technique of donor nephrectomy.

Molecular organization, catalytic mechanism and function of serine hydroxymethyltransferase--a potential target for cancer chemotherapy.

Serine hydroxymethyltransferase, a pyridoxal-5'-phosphate dependent enzyme, catalyzes the retro-aldol cleavage of serine to yield glycine and the hydroxymethyl group is transferred to 5,6,7,8-tetrahydrofolate to generate 5,10-methylene-H4-folate. The enzyme plays a pivotal role in channeling metabolites between amino acid and nucleotide metabolism. Dihydrofolate reductase and thymidylate synthase have been favorite targets for the development of anticancer drugs. However, development of resistance to drugs, due to a variety of reasons, has necessitated the identification of alternate targets for cancer chemotherapy and serine hydroxymethyltransferase is one such potential target. A detailed study of the kinetics of interaction of serine and folate analogs with this enzyme revealed several unique features that can be exploited for the design of new chemotherapeutic agents. The pathways for the reversible unfolding of the dimeric Escherichia coli and the tetrameric sheep liver enzyme, although different, revealed a requirement for the cofactor in the final step for generating an active enzyme. The gly A gene of Escherichia coli has been shown to code for this enzyme. Analysis of available gene sequences indicate that serine hydroxymethyltransferase is one of the most highly conserved proteins. The isolation of the cDNA clones for the enzyme and their overexpression in heterologous systems has enabled the probing of the molecular mechanisms of catalysis and the role of lysine, arginine and histidine in cofactor, substrate(s) binding and in maintaining the structure of the protein. Recently, the three-dimensional structure of the human liver serine hydroxymethyltransferase has been published. This, along with the information already available, provides a framework for the rational design of drugs targeted specifically towards this enzyme.

Meal pattern analysis in response to temporomandibular joint inflammation in the rat.

Inflammation of the temporomandibular joint (TMJ) can alter behavioral responses such as food intake and mobilize stress hormones. The hypothesis of this study was that food intake and diurnal corticosterone analysis can be used as indicators of adjuvant-induced TMJ inflammation. Groups of rats received adjuvant or no injections at the beginning of the resting (AM) or activity (PM) phase. Forty-eight hours (early) or 6 weeks (late) after adjuvant injection, plasma corticosterone was assayed and food intake was recorded. Food intake was suppressed up to 4 days post-injection. As expected, the non-injected group showed low AM and high PM corticosterone. AM corticosterone was elevated, but PM corticosterone was attenuated in both early- and late-stage-injected rats. A computerized pair-fed experiment showed that adjuvant-induced hypophagia did not alter corticosterone levels. Meal pattern analysis revealed decreased food intake due to a decrease in the number of meals taken. Notably, meal size remained the same but meal duration increased. This model demonstrated that food intake and stress hormone analysis could be used as indicators for sequelae of adjuvant-induced TMJ inflammation.

The role of lysine-256 in the structure and function of sheep liver recombinant serine hydroxymethyltransferase.

The active site lysine residue, K256, involved in Schiff's base linkage with pyridoxal-5'-phosphate (PLP) in sheep liver recombinant serine hydroxymethyltransferase (rSHMT) was changed to glutamine or arginine by site-directed mutagenesis. The purified K256Q and K256R SHMTs had less than 0.1% of catalytic activity with serine and H4folate as substrates compared to rSHMT. The mutant enzymes also failed to exhibit the characteristic visible absorbance spectrum (lambda(max) 425 nm) and did not produce the quinonoid intermediate (lambda(max) 495 nm) upon the addition of glycine and H4folate. The mutant enzymes were unable to catalyze aldol cleavage of beta-phenylserine and transamination of D-alanine. These results suggested that the mutation of the lysine had resulted in the inability of the enzyme to bind to the cofactor. Therefore, the K256Q SHMT was isolated as a dimer and the K256R SHMT as a mixture of dimers and tetramers which were converted to dimers slowly. On the other hand, rSHMT was stable as a tetramer for several months, further confirming the role of PLP in maintenance of oligomeric structure. The mutant enzymes also failed to exhibit the increased thermal stability upon the addition of serine, normally observed with rSHMT. The enhanced thermal stability has been attributed to a change in conformation of the enzyme from open to closed form leading to reaction specificity. The mutant enzymes were unable to undergo this conformational change probably because of the absence of bound cofactor.

Mycotic keratitis in Nigeria. A study of 21 cases.

A clinical and mycological study of 21 cases of mycotic keratitis, a clinical entity not yet reported from Nigeria or West Africa, showed that Fusarium solani was the predominant aetiological agent. It was isolated from 12 cases. Four of the remaining nine cases were caused by Aspergillus fumigatus, one by A. flavus, two by Penicillium citrinum, and one each by P. expansum and Penicillium sp. All the 12 isolates of F. solani grew well at 37 degrees C and survived at 40 degrees C. Two cases, one due to F. solani and the other to A. fumigatus, were accompanied by panophthalmitis.

A study of malnutrition among children aged 6 months to 2 years from a resettlement colony of Delhi.

Nutritional status of 1661 children aged 6 months to 2 years who attended the Well Baby Clinic of UHC Gokulpuri, Delhi during the year 2000 was studied. 60.7% of them were malnourished. Undesirable practices of discarding the colostrum, not exclusively breast feeding the child till at least 4 months of age, delayed weaning, dilution of top milk, use of bottle and nipple for feeding the children are still widely prevalent.

An unusual cause of chronic otitis media with effusion.

OBJECTIVE: To describe an unusual cause for hearing loss in an adult. CASE REPORT: A 37-year-old man presented with a year's history of right-sided hearing loss. He had no history of trauma, or local or systemic infection. He was otherwise well, took no medication and had no allergies. He had a two-year history of low back pain. On examination, he had a retracted right tympanic membrane with no perforation, and a middle-ear effusion. Nasendoscopy was normal. Examination of other systems was unremarkable. Computed tomography of the temporal bones with contrast demonstrated a large, right, intra-cerebral internal carotid artery aneurysm compressing the eustachian tube. After a balloon occlusion test, he underwent endovascular occlusion of the parent vessel. He made a good post-operative recovery. A subsequent abdominal ultrasound excluded an abdominal aneurysm as a cause of his low back pain. His hearing had not improved three days post-operatively, and was to be formally assessed and monitored in the clinic. DISCUSSION: A carotid aneurysm is a rare cause of eustachian tube compression but must be considered in the differential diagnosis of conductive hearing loss. Aneurysms may have systemic causes, and their presence in other systems should be excluded as they may be multiple.