Phonons and colossal thermal expansion behavior of Ag3Co(CN)6 and Ag3Fe(CN)6

Recently colossal volume thermal expansion has been observed in the framework compounds Ag(3)Co(CN)(6) and Ag(3)Fe(CN)(6). We have measured phonon spectra using neutron time-of-flight spectroscopy as a function of temperature and pressure. Ab initio calculations were carried out for the sake of analysis and interpretation. Bonding is found to be very similar in the two compounds. At ambient pressure, modes in the intermediate frequency part of the vibrational spectra in the Co compound are shifted slightly to higher energies as compared to the Fe compound. The temperature dependence of the phonon spectra gives evidence for a large explicit anharmonic contribution to the total anharmonicity for low-energy modes below 5 meV. We have found that modes are mainly affected by the change in size of the unit cell, which in turn changes the bond lengths and vibrational frequencies. Thermal expansion has been calculated via the volume dependence of phonon spectra. Our analysis indicates that Ag phonon modes within the energy range 2-5 meV are strongly anharmonic and major contributors to thermal expansion in both systems. The application of pressure hardens the low-energy part of the phonon spectra involving Ag vibrations and confirms the highly anharmonic nature of these modes.

The significance of moment-of-inertia variation in flight manoeuvres of butterflies

The objective of this study is to understand the role that changes in body moment of inertia might play during flight manoeuvres of insects. High-speed, high-resolution videogrammetry is used to quantify the trajectory and body conformation of Painted Lady butterflies during flight manoeuvres; the 3D kinematics of the centre of masses of the various body parts of the insect is determined experimentally. Measurements of the mass properties of the insect are used to parameterize a simple flight dynamics model of the butterfly. Even though the mass of the flapping wings is small compared to the total mass of the insect, these experiments and subsequent analysis indicate that changes in moment of inertia during flight are large enough to influence the manoeuvres of these insects.

Computational modeling of phonatory dynamics in a tubular three-dimensional model of the human larynx

Simulation of the phonatory flow-structure interaction has been conducted in a three-dimensional, tubular shaped laryngeal model that has been designed with a high level of realism with respect to the human laryngeal anatomy. A non-linear spring-based contact force model is also implemented for the purpose of representing contact in more general conditions, especially those associated with three-dimensional modeling of phonation in the presence of vocal fold pathologies. The model is used to study the effects of a moderate (20%) vocal-fold tension imbalance on the phonatory dynamics. The characteristic features of phonation for normal as well as tension-imbalanced vocal folds, such as glottal waveform, glottal jet evolution, mucosal wave-type vocal-fold motion, modal entrainment, and asymmetric glottal jet deflection have been discussed in detail and compared to established data. It is found that while a moderate level of tension asymmetry does not change the vibratory dynamics significantly, it can potentially lead to measurable deterioration in voice quality.

Adrenocortical tumors in children: a Kuwait experience

INTRODUCTION

Adrenocortical tumors (ACT) are rare tumors of childhood. The majority of these tumors is hormone-producing and cause virilization and Cushing syndrome or feminization.

METHODOLOGY

The authors describe 6 cases of adrenal cortical tumors treated at the Kuwait Cancer Center which were presented over a period of 20 years (1989-2009).

RESULTS

The mean age was 5.5 years (range 15 months - 12 years). All had signs of virilization. One child had hypertension, while 2 had a metastatic disease at presentation. The diagnosis was made by clinical signs and symptoms, high levels of relevant adrenal hormones and imaging. Two children were not fit for surgery; one was too sick for any treatment and died shortly after diagnosis, while the other died after receiving one cycle of palliative chemotherapy. Four patients underwent complete surgical resection and achieved complete remission, three of whom later had recurrence (distant in one and local in two patients) and succumbed due to progressive disease. Mitotane was used in two children. Only one patient is currently surviving and well nearly 13 years after her surgery. In our series, the long-term outcome of children with adrenocortical tumors was very poor.

CONCLUSIONS

Virilization is an important clue to the diagnosis of ACT. Early diagnosis and complete surgical resection are important for survival. Metastasis at presentation or as recurrence carries very dismal prognosis.

A clinical trial to assess the immunogenicity and safety of Inactivated Influenza Vaccine (Whole Virion) IP (Pandemic Influenza (H1N1) 2009 Monovalent Vaccine; VaxiFlu-S™) in healthy Indian adult population

BACKGROUND

The pandemic of H1N1 2009 influenza has spread world over and low degree of virus transmission has continued in several regions of India.

AIMS

To assess the immunogenicity and safety of Pandemic Influenza (H1N1) 2009 Monovalent Vaccine in healthy adult Indian population.

SETTINGS AND DESIGN

Prospective, open label, multicentric, phase 2/3 clinical trial.

MATERIALS AND METHODS

Healthy adult Indian subjects belonging to either 18-59 years or ≥ 60 years age groups were enrolled and administered a single 0.5 ml (≥ 15 mcg of hemagglutinin antigen) dose of vaccine in the deltoid muscle. Anti-hemagglutinin antibody titer was assessed at baseline and 21 (± 2) days after vaccination by Hemagglutination Inhibition (HI) test. Safety assessments were done for a period of 42 days.

STATISTICAL ANALYSIS USED

Percentages of appropriate population with 95% confidence intervals calculated, log transformation of the data to calculate Geometric Mean Titers (GMTs) and chi-square test and student's t-test applied for significance testing.

RESULTS

182/198 and 53/63 volunteers in age groups of 18-59 years and ≥ 60 years, respectively, achieved an HI titer ≥ 1 : 40 at Day 21 (91.9% [95% confidence interval: 88.1-95.7%] and 84.1% [75.1-93.2%]; P=0.072). Further, 171/198 and 50/63 volunteers in the respective age groups achieved seroconversion/four-fold increase in titer at Day 21 (86.4% [81.6-91.1%] and 79.4% [69.4-89.4%]; P=0.179). A significant rise of 22.6-fold [18.0-28.4] and 10.5-fold [7.4-15.0] was noted in GMT in the respective age groups (P<0.001 for both groups as compared to baseline). Nine vaccine-related adverse events were reported (3.4% incidence [1.2-5.6%]), which were of low severity only.

CONCLUSIONS

Pandemic Influenza (H1N1) 2009 Monovalent Vaccine produces excellent immunogenic response with a good tolerability profile in adult Indian population.

Simultaneous bilensectomy and endothelial keratoplasty for angle-supported phakic intraocular lens-induced corneal decompensation

A 40-year-old lady presented with severe endothelial cell loss in both eyes 14 years after angle-supported phakic intraocular lens (AS PIOL) implantation. The left eye had severe corneal edema with bullous keratopathy. The right eye had markedly reduced endothelial cell count (655 cells/mm²) although the cornea was clear. She underwent simultaneous bilensectomy (AS PIOL explantation and phacoemulsification) and Descemet's stripping and endothelial keratoplasty (DSEK) in the left eye. Explanted AS PIOL was identified as ZSAL-4 (Morcher, Stuttgart, Germany) model. Corneal edema cleared completely in 2 months with a best corrected visual acuity (-2.25 D sph) of 20/60. No intervention was done in the right eye. The present case illustrates that AS PIOL-induced endothelial decompensation can be effectively managed by simultaneous bilensectomy and endothelial keratoplasty.

Sensitivity of vocal fold vibratory modes to their three-layer structure: implications for computational modeling of phonation

The sensitivity of the eigenmodes and eigenfrequencies of the human vocal fold to its three-layer structure is studied using finite-element modeling. The study covers a variety of three-dimensional vocal fold models ranging from an idealized, longitudinally uniform structure to a physiologically more realistic, longitudinally varying structure. Geometric parameters including the thickness of the ligament and cover layers as well as the ligament length are varied systematically. The results indicate that vocal fold vibratory modes are quite insensitive to the longitudinal variation in the thickness of the three layers as well as the variation in ligament length. However, significant overall changes in thickness of each layer can produce noticeable changes in these modes. The implications of these findings on computational modeling of phonation are discussed.

Direct-numerical simulation of the glottal jet and vocal-fold dynamics in a three-dimensional laryngeal model

An immersed-boundary method based flow solver coupled with a finite-element solid dynamics solver is employed in order to conduct direct-numerical simulations of phonatory dynamics in a three-dimensional model of the human larynx. The computed features of the glottal flow including mean and peak flow rates, and the open and skewness quotients are found to be within the normal physiological range. The flow-induced vibration pattern shows the classical "convergent-divergent" glottal shape, and the vibration amplitude is also found to be typical for human phonation. The vocal fold motion is analyzed through the method of empirical eigenfunctions and this analysis indicates a 1:1 modal entrainment between the "adduction-abduction" mode and the "mucosal wave" mode. The glottal jet is found to exhibit noticeable cycle-to-cycle asymmetric deflections and the mechanism underlying this phenomenon is examined.

A computational study of asymmetric glottal jet deflection during phonation

Two-dimensional numerical simulations are used to explore the mechanism for asymmetric deflection of the glottal jet during phonation. The model employs the full Navier-Stokes equations for the flow but a simple laryngeal geometry and vocal-fold motion. The study focuses on the effect of Reynolds number and glottal opening angle with a particular emphasis on examining the importance of the so-called "Coanda effect" in jet deflection. The study indicates that the glottal opening angle has no substantial effect on glottal jet deflection. Deflection in the glottal jet is always preceded by large-scale asymmetry in the downstream portion of the glottal jet. A detailed analysis of the velocity and vorticity fields shows that these downstream asymmetric vortex structures induce a flow at the glottal exit which is the primary driver for glottal jet deflection.

Compressive Optic Neuropathy Caused by a Cholesterol Granuloma of the Sphenoidal Sinus

Cholesterol granuloma is a foreign body giant cell reaction to cholesterol deposits. The pathology is rarely seen in the paranasal sinuses. In this report we describe a case of compressive optic neuropathy caused by cholesterol granuloma arising from the sphenoidal sinus. A 46-year-old lady presented with painless progressive decrease in vision in her left eye over the past 7 years. Magnetic resonance imaging of the brain and orbit with gadolinium enhancement showed a homogenous T1 and T2 hyperintense lesion causing expansion of the sphenoidal sinus compressing the ethmoidal sinus and also the left optic nerve. An endoscopic marsupialisation of the lesion was performed. Histopathological examination showed multiple characteristic cholesterol clefts surrounded by numerous multinucleated giant cells, histiocytes, lymphocytes, haemosiderin-laden macrophages, and plasma cells. This case emphasises the importance of appropriate neuro-imaging in cases of progressive optic neuropathy: cholesterol granuloma of the paranasal sinuses is a rare cause of optic nerve compression.

Stiffness of desiccating insect wings

The stiffness of insect wings is typically determined through experimental measurements. Such experiments are performed on wings removed from insects. However, the wings are subject to desiccation which typically leads to an increase in their stiffness. Although this effect of desiccation is well known, a comprehensive study of the rate of change in stiffness of desiccating insect wings would be a significant aid in planning experiments as well as interpreting data from such experiments. This communication presents a comprehensive experimental analysis of the change in mass and stiffness of gradually desiccating forewings of Painted Lady butterflies (Vanessa cardui). Mass and stiffness of the forewings of five butterflies were simultaneously measured every 10 min over a 24 h period. The averaged results show that wing mass declined exponentially by 21.1% over this time period with a time constant of 9.8 h, while wing stiffness increased linearly by 46.2% at a rate of 23.4 µN mm(-1) h(-1). For the forewings of a single butterfly, the experiment was performed over a period of 1 week, and the results show that wing mass declined exponentially by 52.2% with a time constant of 30.2 h until it reached a steady-state level of 2.00 mg, while wing stiffness increased exponentially by 90.7% until it reached a steady-state level of 1.70 mN mm(-1).

A coupled sharp-interface immersed boundary-finite-element method for flow-structure interaction with application to human phonation

A new flow-structure interaction method is presented, which couples a sharp-interface immersed boundary method flow solver with a finite-element method based solid dynamics solver. The coupled method provides robust and high-fidelity solution for complex flow-structure interaction (FSI) problems such as those involving three-dimensional flow and viscoelastic solids. The FSI solver is used to simulate flow-induced vibrations of the vocal folds during phonation. Both two- and three-dimensional models have been examined and qualitative, as well as quantitative comparisons, have been made with established results in order to validate the solver. The solver is used to study the onset of phonation in a two-dimensional laryngeal model and the dynamics of the glottal jet in a three-dimensional model and results from these studies are also presented.

Voriconazole-refractory fungal infection of phacoemulsification tunnel

A 44-year-old man presented 28 days after cataract surgery (phacoemulsification) in right eye with multiple pinpoint infiltrates in posterior stroma at cataract surgery wound site. Visual acuity was 20/60. Corneal scraping from the floor of the corneal tunnel revealed fungus which was later identified to be Aspergillus flavus. The patient was started on oral voriconazole 200 mg twice daily and topical voriconazole 1% every hour. Two intracameral injections of voriconazole (50 micrograms/ 0.1 ml) were given 72 h apart, five days after starting initial therapy. Infiltrates increased in size and density in spite of 20 days of voriconazole therapy. Full-thickness patch graft was done to arrest progressive necrosis. Four months after surgery, patient had 20/60 best-corrected visual acuity. There was no recurrence in one-year follow-up. Present case illustrates the therapeutic challenge in fungal tunnel infections and possibility of voriconazole-resistant Aspergillus species.

A computational study of the effect of vocal-fold asymmetry on phonation

Unilateral laryngeal paralysis leads to tension imbalance and hence to asynchronous movements between the two vocal folds during phonation. In the current study, a computational model of phonation that couples a two-mass model of the vocal folds with a Navier-Stokes model of the glottal airflow, has been used to examine the dynamics of vocal fold configurations with tension imbalance and its implications for phonation. The simulations show that tension imbalance influences phonation onset, intensity as well as the fundamental phonation frequency. Distinct non-linear effects such as period-doubling bifurcation and preferential frequency selection are also observed.