Ab interno tube ligation for refractory hypotony following non-valved glaucoma drainage device implantation.

PURPOSE: To report the 2-year outcomes of a novel surgical technique allowing reduction of the intraluminal diameter of the tube without total tube occlusion in order to allow enough increase in outflow resistance to permit resolution of hypotony whilst also achieving adequate IOP control. METHODS: This was a single-surgeon retrospective case note review of all non-valved GDD cases over an 8-year period (2008-2015) that underwent ab interno ligation of the drainage tube in order to manage post-operative hypotony (Baerveldt or Molteno). Twelve eyes of 12 patients (4.4%) developing refractory hypotony that did not respond to multiple intracameral ophthalmic viscoelastic device (OVD) injections were included in this retrospective case series and were treated with our ab interno tube ligation technique. The post-ligation management algorithm consisted of re-instating topical anti-glaucoma agents, laser suture lysis (LSL), or further ab interno ligation. RESULTS: Mean IOP increased from 2.8 mmHg at baseline to 7.8 mmHg, 7.1 mmHg, 9.0 mmHg, 13.6 mmHg, 10.9 mmHg, 13.9 mmHg and 13.6 mmHg at day 1, week 1, month 1, month 3, month 6, year 1 and year 2 respectively, with or without additional topical anti-glaucoma medications. Although hypotony resolution following our technique was achieved in all eyes at 2 years, 8.3% of cases required reinstatement of topical medications to maintain IOP control within the target range. CONCLUSIONS: We propose ab interno partial tube tying as an effective surgical option to achieve an immediate, predictable and sustained IOP elevation either as a primary procedure or when traditional methods have failed to resolve hypotony in eyes with non-valved GDDs.

Highly efficient charge separation and collection across in situ doped axial VLS-grown Si nanowire p-n junctions.

VLS-grown semiconductor nanowires have emerged as a viable prospect for future solar-based energy applications. In this paper, we report highly efficient charge separation and collection across in situ doped Si p-n junction nanowires with a diameter <100 nm grown in a cold wall CVD reactor. Our photoexcitation measurements indicate an internal quantum efficiency of ~50%, whereas scanning photocurrent microscopy measurements reveal effective minority carrier diffusion lengths of ~1.0 µm for electrons and 0.66 µm for holes for as-grown Si nanowires (d(NW) ≈ 65-80 nm), which are an order of magnitude larger than those previously reported for nanowires of similar diameter. Further analysis reveals that the strong suppression of surface recombination is mainly responsible for these relatively long diffusion lengths, with surface recombination velocities (S) calculated to be 2 orders of magnitude lower than found previously for as-grown nanowires, all of which used hot wall reactors. The degree of surface passivation achieved in our as-grown nanowires is comparable to or better than that achieved for nanowires in prior studies at significantly larger diameters. We suggest that the dramatically improved surface recombination velocities may result from the reduced sidewall reactions and deposition in our cold wall CVD reactor.

Scaling law for excitons in 2D perovskite quantum wells.

Ruddlesden-Popper halide perovskites are 2D solution-processed quantum wells with a general formula A2A'n-1M n X3n+1, where optoelectronic properties can be tuned by varying the perovskite layer thickness (n-value), and have recently emerged as efficient semiconductors with technologically relevant stability. However, fundamental questions concerning the nature of optical resonances (excitons or free carriers) and the exciton reduced mass, and their scaling with quantum well thickness, which are critical for designing efficient optoelectronic devices, remain unresolved. Here, using optical spectroscopy and 60-Tesla magneto-absorption supported by modeling, we unambiguously demonstrate that the optical resonances arise from tightly bound excitons with both exciton reduced masses and binding energies decreasing, respectively, from 0.221 m0 to 0.186 m0 and from 470 meV to 125 meV with increasing thickness from n equals 1 to 5. Based on this study we propose a general scaling law to determine the binding energy of excitons in perovskite quantum wells of any layer thickness.

Pseudodacryocystitis: paediatric case series of infected atypical ethmoid air cells masquerading as recurrent dacryocystitis.

PurposeTo highlight the clinical and surgical considerations in treating patients with apparent recurrent acute dacryocystitis with a patent lacrimal system.MethodsThree children referred to a tertiary unit as recurrent acute dacryocystitis were reviewed retrospectively. Imaging and subsequent surgical intervention revealed the underlying diagnosis.ResultsAll three cases presented with recurrent abscesses in the region of the lacrimal sac that failed to respond to incision and drainage. The lesions were lower and more lateral to the usual location of a sac abscess and closer to the inferior orbital rim. All three cases were found to have patent lacrimal systems on syringing, and all were found to have infected, low-lying, anteriorly placed aberrant ethmoid air cells on computed tomography and magnetic resonance imaging. These were confirmed on subsequent surgical exploration.ConclusionsInfected low-lying ethmoid air cells can mimic dacryocystitis with recurrent abcesses. In cases where a patent nasolacrimal system is demonstrated and a more inferolateral location of the swelling than would be expected in dacryocystitis is seen, imaging is warranted to ensure the appropriate intervention is undertaken. Anterior ethmoidectomy as opposed to dacryocystorhinostomy is the appropriate treatment in these cases.

Extremely efficient internal exciton dissociation through edge states in layered 2D perovskites.

Understanding and controlling charge and energy flow in state-of-the-art semiconductor quantum wells has enabled high-efficiency optoelectronic devices. Two-dimensional (2D) Ruddlesden-Popper perovskites are solution-processed quantum wells wherein the band gap can be tuned by varying the perovskite-layer thickness, which modulates the effective electron-hole confinement. We report that, counterintuitive to classical quantum-confined systems where photogenerated electrons and holes are strongly bound by Coulomb interactions or excitons, the photophysics of thin films made of Ruddlesden-Popper perovskites with a thickness exceeding two perovskite-crystal units (>1.3 nanometers) is dominated by lower-energy states associated with the local intrinsic electronic structure of the edges of the perovskite layers. These states provide a direct pathway for dissociating excitons into longer-lived free carriers that substantially improve the performance of optoelectronic devices.

Outcome of Interlay Grafting in Type 1 Tympanoplasty for Large Central Perforation.

A prospective, cohort, clinical study was conducted at Dr. D. Y. Patil Hospital, Kolhapur from August 2010 to August 2013. The aim was to evaluate the results of type 1 interlay tympanoplasty with respect to graft uptake, hearing improvement and complications. Total of 100 cases with a mucosal type of chronic suppurative otitis media and a large central perforation (involving more than 50 % of tympanic membrane) were operated for type 1 tympanoplasty where the graft was placed by interlay method (below the fibro-squamous layer and above the mucosal or endothelial layer). Patients were followed up with ear microscopy at each follow up visit and an audiometry at the end of 3rd month. Statistical analysis was done by statcal software using paired t test and two sample t test for proportion. 96 (96 %) cases had a successful graft uptake. The mean pre-operative air-bone gap was 36.42 ± 12.0 dB; whereas the mean post-operative air-bone gap was 9.7 ± 6.71 dB. Except for residual perforation in four patients and partial tympanomeatal flap necrosis in two patients no other complications were encountered. Thus, we conclude that, the interlay tympanoplasty is a safe and effective method of graft placement for large central perforation.

Rhinocerebral mucormycosis: A deadly disease on the rise.

According to WHO, there will be epidemic of diabetes world over and India is going to be 'A diabetes capital of the world' by 2025. With the increasing incidence of diabetes, the associated complications are also bound to increase. Rhinocerebral mucormycosis is one of them.Rhinocerebral Mucormycosis is an opportunistic, fulminating fungal infection, caused by Rhizopus species of order of mucorales, frequently seen in diabetic and immunocompromised patients. Mucormycosis has a very high mortality rate.Early diagnosis and treatment with Amphotericin-B is the key to combat this disease successfully. We have seen 13 cases in last 3 years (2002-2005) in our area. This incidence is significant, as this type of cases were rarely seen before 2002, in this geographical area. We present an account of these cases; treatment strategies adopted, review of literature, and highlight 'the role of ENT surgeon in diagnosis and management of this dreadful disease'.

Study of beta-adrenoreceptor antagonistic activity of DPJ 904 in rats.

beta-Adrenoreceptor antagonistic activity of a newly synthesized compound was evaluated in vivo by measuring the mean arterial blood pressure and heart rate of urethane-anesthetized rats treated with isoprenaline. In vitro beta(1)-, beta(2)- and beta(3)-antagonism was studied using isolated rat right atria, isolated rat uterus and isolated rat colon preparations, respectively, in comparison to isoprenaline response. DPJ 904 (1, 3 and 10 mg/kg, i.v.) produced dose-dependent hypotensive and bradycardia response in anesthetized rat. DPJ 904 (1, 3 and 10 mg/kg, i.v.) significantly inhibited both the tachycardial effects and hypotensive response induced by isoprenaline. DPJ 904-antagonized isoprenaline induced positive chronotropic effects of isolated rat right atria and a uterine relaxant effect indicating beta(1)- and beta(2)-blockade. The parallel shift to the right of the concentration-response curve of isoprenaline in the presence of DPJ 904 in KCl (30 mmol/l) induced contraction of the rat colon suggesting that DPJ 904 also possessed beta(3)-adrenoreceptor antagonistic activity. The selectivity to beta(1)-adrenoreceptor was nearly 20.5 times greater than to beta(2)-adrenoreceptor. The present study indicates that DPJ 904 possesses beta-adrenoreceptor antagonistic activity with slightly more affinity to the beta(1)-adrenoreceptor subtype.