Other Causes of Chronic Diarrhea in Children

Chronic diarrhea is still an important cause of morbidity and mortality in children. There are several causes of chronic diarrhea which may be due to intestinal, extra-intestinal or underlying systemic diseases. The etiology varies depending on the age of onset and may include both common and uncommon disorders. In this article some of the uncommon disorders such as immune deficiencies, intestinal lymphangiectasias, drug induced diarrhea, eosinophilic gastrointestinal disorders, endocrinopathies, neuroendocrine secretory tumors, malignancy and factitious diarrhea have been included. Though these disorders are uncommon it is essential that they are considered in select situations as detailed below and evaluated so that definitive therapy may be offered.

Localisation of vibrational modes in high-entropy oxides

The recently-discovered high-entropy oxides (HEO's) offer a paradoxical combination of crystalline arrangement and high disorder. They differ qualitatively from established paradigms for disordered solids such as glasses and alloys. In these latter systems, it is well known that disorder induces localised vibrational excitations. In this article, we explore the possibility of disorder-induced localisation in Mg0.2Co0.2Ni0.2Cu0.2Zn0.2O, the prototypical HEO with rock-salt structure. To describe phononic excitations, we model the interatomic potentials for the cation-oxygen interactions by fitting to the physical properties of the parent binary oxides. We validate our model against the experimentally determined crystal structure and optical conductivity. The resulting phonon spectrum shows wave-like propagating modes at low energies and localised modes at high energies. Localisation is reflected in signatures such as participation ratio and correlation amplitude. Finally, we argue that mass disorder can be increased to enhance localisation. We consider a hypothetical material, high-entropy telluride-oxide, where tellurium atoms are admixed into the anion sublattice. This shows a larger localised fraction, with additional localised modes appearing in the middle of the spectrum. Our results demonstrate that HEO's are a promising platform to study Anderson localisation of phonons.

Role of translational noise on current reversals of active particles on ratchet

In this study, we explore using Langevin dynamics simulations, the role of thermal fluctuations on the rectification of non-interacting inertial active (self-propelled) particles in a rocking ratchet setup in the absence and in the presence of the external time periodic drive. The system is first studied in the absence of the external drive. It is found that the average velocity is always positive and a peaked function of the translational noise, indicating that the asymmetry effects dominate at intermediate values of the strength of the thermal noise. In the second part of this work, we study the effect of the external drive on the dynamics of the system by exploring a phase diagram in the parameter space of translational noise and driving frequency for two different strengths of rotational diffusion. For a given constant amplitude of the active force and amplitude of external drive less than the maximum force due to the potential, the average velocity magnitude as well as the direction ([Formula: see text]) is found to depend on the rotational diffusion, frequency of the external drive and the strength of the translational noise. We discover certain critical parameters in the phase space at which current reversals happen. It is found that when the average particle energy is lower than the potential energy of the barrier, symmetry breaking dominates and the currents are in the 'easy' direction of the ratchet. On the other hand, when the energy available per particle crosses the potential energy of the barrier, the competition between inertial effects and diffusion effects decides the direction of currents. We explain our findings by constructing phase difference datum, velocity probability distribution, and current probability analyses. Our results provide a novel method for controlling the direction of transport of inertial active particles.

Correlations in randomly stacked solids

Packing of spheres is a problem with a long history dating back to Kepler's conjecture in 1611. The highest density is realized in face-centered-cubic (FCC) and hexagonal-close-packed (HCP) arrangements. These are only limiting examples of an infinite family of maximal-density structures called Barlow stackings. They are constructed by stacking triangular layers, with each layer shifted with respect to the one below. At the other extreme, Torquato-Stillinger stackings are believed to yield the lowest possible density while preserving mechanical stability. They form an infinite family of structures composed of stacked honeycomb layers. In this article, we characterize layer-correlations in both families when the stacking is random. To do so, we take advantage of the Hägg code-a mapping between a Barlow stacking and a one-dimensional Ising magnet. The layer correlation is related to a moment-generating function of the Ising model. We first determine the layer correlation for random Barlow stacking, finding exponential decay. We next introduce a bias favoring one of two stacking chiralities-equivalent to a magnetic field in the Ising model. Although this bias favors FCC ordering, there is no long-ranged order as correlations still decay exponentially. Finally, we consider Torquato-Stillinger stackings, which map to a combination of an Ising magnet and a three-state Potts model. With random stacking, the correlations decay exponentially with a form that is similar to the Barlow problem. We discuss relevance to ordering in clusters of stacked solids and for layer-deposition-based synthesis methods.

Current management of appendicular mas - a narrative review

Appendicular mass is considered as one of the complications of acute appendicitis but there is no consensus on the optimal management of this condition. The management of this condition has always been conservative management with interval appendectomy as popularized by Oschner and Sheerin. The need for interval appendectomy has now been questioned, and an emerging trend has been early appendectomy by laparoscopic method. There are no guidelines on the management of appendicular mass and treatment is decided by the surgeon. We have conducted a narrative review to investigate what is the current practice in the management of appendicular mass.

Collective behavior of soft self-propelled disks with rotational inertia

We investigate collective properties of a large system of soft self-propelled inertial disks with active Langevin dynamics simulation in two dimensions. Rotational inertia of the disks is found to favor motility induced phase separation (MIPS), due to increased effective persistence of the disks. The MIPS phase diagram in the parameter space of rotational inertia and disk softness is reported over a range of values of translation inertia and self-propulsion strength of the disks. Our analytical prediction of the phase boundary between the homogeneous (no-MIPS) and MIPS state in the limit of small and large rotational inertia is found to agree with the numerical data over a large range of translational inertia. Shape of the high density MIPS phase is found to change from circular to rectangular one as the system moves away from the phase boundary. Structural and dynamical properties of the system, measured by several physical quantities, are found to be invariant in the central region of the high density MIPS phase, whereas they are found to vary gradually near the peripheral region of the high density phase. Importantly, the width of the peripheral region near the phase boundary is much larger compared to the narrow peripheral region far away from the phase boundary. Rich dynamics of the disks inside the high density MIPS phase is addressed. Spatial correlation of velocity of the disks is found to increase with rotational inertia and disk hardness. However, temporal correlation of the disks' velocity is found to be a function of rotational inertia, while it is independent of disk softness.

Motility-induced phase separation of self-propelled soft inertial disks

The phase diagram of the phenomenon of motility-induced phase separation (MIPS) for a collection of self-propelled interacting disks over a large inertial range is explored using active Langevin dynamics simulation with particular emphasis on disk softness and effective size. It is shown that the parabola-like phase boundary between the homogeneous and MIPS states in the semi-log space of disk softness and effective size moves towards the hard disk limit with increase in inertia, before complete disappearance in the limit of large inertia. With increase in effective size of the disks, re-entrant phase separation, that is the system phase-separating from a homogeneous phase and eventually re-entering the homogeneous phase, is reported. The structural and the dynamical properties of the different phases are investigated in the considered inertial range. The particular shape of the phase boundary and the re-entrant behavior is explained based on several qualitative and quantitative results. Unlike most of the earlier studies on MIPS, which consider hard particle limits, our findings may be directly applicable to soft active matter for a range of physical and biological systems.

Reentrant phase separation of a sparse collection of nonreciprocally aligning self-propelled disks

We study a model of aligning self-propelled disks that nonreciprocally reorient the self-propulsion directions along the interparticle separation and towards the other disks. In the limit of small inertia and large softness, where conventional motility-induced phase separation is absent, we demonstrate that the homogeneous system at a small area fraction phase-separates into clusters and a low-density phase that, eventually, reenters the homogeneous phase with a monotonic increase in alignment strength. The disks inside the clusters move with a finite space-dependent speed, constantly shuttling between clusters through the surrounding low-density homogeneous phase while maintaining the hexatic structure properties within the clusters. The area fraction gradually increases from the periphery towards the center of the clusters with a negligible correlation of the velocity and propulsion direction inside the clusters. The novel collective behavior of reentrant phase separation is found to follow from both the limits of hard disks and extremely small inertia, tending towards the overdamped limit. However, important differences in the structural and dynamical properties are shown in the limit of hard disks and extremely small inertia, as compared to that for soft disks at finite inertia. We show that the cluster phase is associated with an effective temperature for a wide range of values of alignment strength, whereas an effective temperature is associated with the specific range of alignment in the low-density phase. We believe that the reentrant phase behavior in the limit of small area fraction and the remarkable properties of the clusters should be useful in understanding a wide range of physics issues, ranging from clogging and unclogging to information exchange and transport, in biological and synthetic self-propelled systems.

Phase transition and emergence of active temperature in an active Brownian system in underdamped background

We explore the role of inertia in the properties of active Brownian particles (ABPs) immersed in an underdamped background in two dimensions using Langevin dynamics computer simulation. Similar to an equilibrium two-dimensional passive interacting particle system, the system of ABPs transits from a liquid phase to a solid phase with the change in the coupling parameter, which is the ratio of interaction potential energy and thermal energy of the background solvent. Important qualitative and quantitative differences are found in the liquid-solid phase transition with increasing strength of activity as compared to those found in the conventional overdamped background limit. In the underdamped background, inherent activity is found to lead to a temperature, called the active temperature and defined by average velocity fluctuations of the ABPs, that is different from the fixed background solvent temperature. A new scaling law for active temperature as a function of activity strength is found near the liquid-solid boundary. Active temperature, which behaves similar to the thermodynamic equilibrium temperature, is also found to depend upon the interaction strength between the active particles and the strength of the background dissipation. With an increase in background dissipation, the difference between active temperature and the background solvent temperature decreases and the difference is found to eventually vanish in the overdamped limit, demonstrating the correctness of the calculation.

Negative entropy-production rate in Rayleigh-Bénard convection in two-dimensional Yukawa liquids

The steady-state fluctuation theorem (SSFT) gives the relative probability of occurrence of events violating the second law of thermodynamics in a system with a small number of degrees of freedom. Using two-dimensional complex plasma as a working medium, wherein particle level observation of instantaneous velocities and positions has become experimentally possible, we perform "first-principles" molecular-dynamics simulations using the Yukawa potential in the presence of external gravity and an external temperature gradient leading to the onset and formation of Rayleigh-Bénard convection cells. In such a far-from-equilibrium steady state, the SSFT is put to the test. It is demonstrated that the SSFT is satisfied without any additional fit parameter for observation time τ, comparable to or greater than the relevant microscopic timescale associated with the system under observation.

Factors influencing paediatric neck abscess and treatment at Hospital Tuanku Jaafar, Seremban

BACKGROUND

This is a descriptive study of in-patient paediatric population with the diagnosis of neck abscess. The objective of this study was to calculate the number of children who require conservative (antibiotic) management compared to surgery for neck abscess. A second objective was to identify the factors influencing the choice of the treatments selected.

METHODS

A retrospective review was performed on a group of paediatric population aged 0 till 12 years of age, with a history of admission to paediatric ENT ward from the year 2010 till 2015 in HTJS. Initially, 69 children with the diagnoses of various neck infections were identified. Then, the sample amount was narrowed to 30 patients with neck abscesses only.

RESULTS

The data analysis was performed using descriptive statistics, Chi-squared test and Fisher's exact test. Twentyfive out of the 30 patients required operative drainage of abscess (83.3%). In this group, children aged ≤2 years old were the largest group to have undergone surgical drainage. Only five patients were successfully treated with antibiotic therapy alone. Nineteen children came only after developing neck swelling for more than a week, in which 18 of them required surgery.

CONCLUSION

Younger group of children are more likely to undergo surgical drainage than older children for neck abscess. Also, children who came in after two weeks of symptoms have a higher probablity of requiring surgery than antbiotic alone. Nonetheless, every child who comes in with neck abscess should be evaluated and treated early to avoid any sinister complications.

A new multi-line cusp magnetic field plasma device (MPD) with variable magnetic field

A new multi-line cusp magnetic field plasma device consisting of electromagnets with core material has been constructed with a capability to experimentally control the relative volume fractions of magnetized to unmagnetized plasma volume as well as accurate control on the gradient length scales of mean density and temperature profiles. Argon plasma has been produced using a hot tungsten cathode over a wide range of pressures 5 × 10^-5 -1 × 10^-3 mbar, achieving plasma densities ranging from 10⁹ to 10¹¹ cm^-3 and the electron temperature in the range 1-8 eV. The radial profiles of plasma parameters measured along the non-cusp region (in between two consecutive magnets) show a finite region with uniform and quiescent plasma, where the magnetic field is very low such that the ions are unmagnetized. Beyond that region, both plasma species are magnetized and the profiles show gradients both in temperature and density. The electrostatic fluctuation measured using a Langmuir probe radially along the non-cusp region shows less than 1% (δI_isat/I_isat < 1%). The plasma thus produced will be used to study new and hitherto unexplored physics parameter space relevant to both laboratory multi-scale plasmas and astrophysical plasmas.

Fiber reinforced composites in prosthodontics - A systematic review

Fiber-reinforced composite (FRC), prostheses offer the potential advantages of optimized esthetics, low wear of the opposing dentition and the ability to bond the prosthesis to the abutment teeth, thereby compensating for less-than-optimal abutment tooth retention and resistance form. These prostheses are composed of two types of composite materials: Fiber-composites to build the substructure and hybrid or micro fill particulate composites to create the external veneer surface. This article reviews the various types of FRCs and its mechanical properties.

A simple experimental method to determine magnetic field topology in toroidal plasma devices

Estimation of the parallel wavenumber in plasma devices finds wide applications such as determining the nature of instabilities. This task is often challenging, especially in toroidal magnetic configurations. In the present work, a simple yet effective method of achieving accurate probe-alignment along the magnetic field lines is demonstrated in a simple magnetized toroidal device BETA (Basic Experiments in Toroidal Assembly). The alignment was achieved by aligning each probe to a tiny localized plasma source. Such an alignment is necessary for determining the parallel wavenumber precisely. The probe-alignment was confirmed further from the measurements in the plasma and the corresponding parallel wavenumber was found to be in good agreement with the analytical predictions.

From modal mixing to tunable functional switches in nonlinear phononic crystals

We introduce a paradigm for spatial and modal wave manipulation based on nonlinear phononic crystals and explore its potential for engineering wave control systems with tunable, adaptive, and multifunctional characteristics. Our approach exploits nonlinear mechanisms to stretch the frequency signature of the wave response and distribute it over multiple modes, thereby activating a mixture of modal characteristics and enabling functionalities associated with high-frequency optical modes, even while operating in the low-frequency regime. To elucidate the versatility of this approach, we consider different granular crystal configurations that span the available landscape of crystal topologies and wave control functionalities. The ability to switch between complementary functionalities allows rethinking nonlinear phononic crystals as programmable acoustic ports that form the building blocks of a new structural logic framework enabled by nonlinearity.

Theoretical prediction of a time-reversal broken chiral superconducting phase driven by electronic correlations in a single TiSe₂ layer

Bulk TiSe2 is an intrinsically layered transition metal dichalcogenide hosting both superconducting and charge-density-wave ordering. Motivated by the recent progress in preparing two-dimensional transition metal dichalcogenides, we study these frustrated orderings in a single trilayer of TiSe2. Using a renormalization group approach, we find that electronic correlations can give rise to charge-density-wave order and two kinds of superconductivity. One possible superconducting state corresponds to unconventional s(+-) pairing. The other is particularly exciting as it is chiral, breaking time-reversal symmetry. Its stability depends on the precise strength and screening of the electron-electron interactions in two-dimensional TiSe2.

Invariants of nonlinearity in the phononic characteristics of granular chains

In this work, we analyze the phononic characteristics of wave motion in precompressed monoatomic and diatomic granular chains, with emphasis on the evolving spatial features of wave packets. A Taylor series expansion of the governing equations is considered to approximate the granular chain with the Fermi-Pasta-Ulam chain. Within this approximation, the envelope modulation of the first-order features of the wave profile is monitored and the characteristics of this modulation are determined by studying the evolution of one of the distinctive features of the spatial profile. A set of constants that describe the quantitative effects of nonlinearity on the response are determined for monoatomic and diatomic chains and interpreted as invariants of quadratic nonlinearity. The universality of these invariants is verified by constructing inverse problems to estimate the contact power law from the wave response of granular chains with arbitrary nonlinear force interaction. The imposed power law is recovered exactly from numerical simulations for a number of considered scenarios, paving the way for inverse characterization of nonlinearity from experimental data.

Deconfined criticality in the frustrated Heisenberg honeycomb antiferromagnet

Using the density matrix renormalization group, we determine the phase diagram of the spin-1/2 Heisenberg antiferromagnet on a honeycomb lattice with a nearest-neighbor interaction J(1) and a frustrating, next-nearest-neighbor exchange J(2). As frustration increases, the ground state exhibits Néel, plaquette, and dimer orders, with critical points at J(2)/J(1) = 0.22 and 0.35. We observe that both the spin gap and the corresponding order parameters vanish continuously at both the critical points, indicating the presence of deconfined quantum criticality.

Comparison of the bleaching efficacy of three different agents used for intracoronal bleaching of discolored primary teeth: an in vitro study

Everyone wants whiter teeth to make them feel younger and to provide beautiful smiles with the accompanying increase in self-esteem. Bleaching is an established, simple, cost-effective and conservative method for improving the color of the discolored teeth.

AIM

The aim of this in vitro study was to compare the bleaching efficacy of 10% carbamide peroxide, 10% hydrogen peroxide and 2g sodium perborate as bleaching agents on the artificially discolored human primary maxillary central incisors.

MATERIALS AND METHODS

Forty extracted human primary central incisors with intact crowns were selected for the study. Pulpectomy was performed and each tooth was artificially stained with 2 ml of fresh human blood and centrifuged. --The teeth were randomly divided into four experimental groups of 10 teeth each and the baseline color evaluation was performed. 0.04 ml of the bleaching agent is syringed into the access cavity of the tooth and, in the control group, 0.04 ml of distilled water was syringed into the access cavity and it was sealed with IRM and placed at 37°C in an incubator throughout the experiment. The color of the bleached teeth was determined at 0, 7 and 14 days. The data obtained were analyzed using ANOVA and Turkey's test.

RESULTS

There was statistical significance (P = 0.00) among the carbamide peroxide, sodium perborate, hydrogen peroxide and control groups after 7 and 14 days and a significance of P = 0.013 among the carbamide peroxide, sodium perborate and hydrogen peroxide after two bleaching sessions (day 14) was seen.

CONCLUSIONS

The bleaching efficacy of 10% hydrogen peroxide gel was more effective than 10% carbamide peroxide and sodium perborate in bleaching the artificially discolored primary teeth.

Profile of EBV associated infectious mononucleosis

During a 5 year period, 33 children (22 males) were diagnosed to have infectious mononucleosis (M:F::2:1; age 9 mo-15 y). The common clinical features observed were fever (100%), lymphadenopathy (84%) hepatosplenomegaly (81%), tonsillar enlargement (45%), neck swelling (30%), upper respiratory symptoms (21%), epitrochlear node enlargement (20%), vomiting and diarrhea (1%). Ten children had complications; upper airway obstruction and hemophagocytic lymphohistocytosis occurred in four each and septic shock in two. EBV associated infectious mononucleosis in hospitalized children was found to affect mainly preschool children and had a favorable prognosis.

Comparison of a rapid commercial test, Enterocheck WB(®), with automated blood culture for diagnosis of typhoid fever

BACKGROUND

Rapid diagnosis of typhoid fever is very important in the timely initiation of therapy.

OBJECTIVES

To evaluate the sensitivity and specificity of the Enterocheck WB(®) test.

METHODS

In a prospective study, the sensitivity and specificity of Enterocheck WB(®) that detects IgM antibodies to Salmonella typhi were compared with blood culture using BacT/Alert.

RESULTS

Four hundred and fifty patients with suspected typhoid fever were assessed both by blood culture and Enterocheck WB(®); 100 of them were either Enterocheck WB(®)-positive or blood culture-positive or both for S. typhi. Both tests were positive in 47 of the 100 patients. In 45 patients, Enterocheck WB(®) was positive but blood culture was negative. In eight cases, Enterocheck was negative but blood culture was positive. Using blood culture as the gold standard, the sensitivity of Enterocheck WB(®) was 85.5%, specificity 88.6%, negative predictive value 97.7% and positive predictive value 51.1%.

CONCLUSION

The Enterocheck WB(®) test can be performed at the bedside in 15 minutes and is a useful rapid method for diagnosis of typhoid fever.

Coherent vortices in strongly coupled liquids

Strongly coupled liquids are ubiquitous in both nature and laboratory plasma experiments. They are unique in the sense that their average potential energy per particle dominates over the average kinetic energy. Using "first principles" molecular dynamics (MD) simulations, we report for the first time the emergence of isolated coherent tripolar vortices from the evolution of axisymmetric flows in a prototype two-dimensional (2D) strongly coupled liquid, namely, the Yukawa liquid. Linear growth rates directly obtained from MD simulations are compared with a generalized hydrodynamic model. Our MD simulations reveal that the tripolar vortices persist over several turn over times and hence may be observed in strongly coupled liquids such as complex plasma, liquid metals and astrophysical systems such as white dwarfs and giant planetary interiors, thereby making the phenomenon universal.

Early improvement in type 2 diabetes mellitus post Roux-en-Y gastric bypass in Asian patients

INTRODUCTION

Obesity is a growing problem worldwide that is closely related to type 2 diabetes mellitus (T2DM). The Roux-en-Y gastric bypass (RYGBP), a restrictive and malabsorptive bariatric procedure, shows mounting evidence of inducing improvement of T2DM. Few studies, especially those examining the early changes in diabetic parameters, have been done in the Asian population.

METHODS

All morbidly obese patients with T2DM undergoing RYGBP at our institution from August 2008 to January 2010 were prospectively studied. Six patients had RYGBP, and one had a laparoscopic sleeve gastrectomy with a duodenojejunal bypass. Data collected included pre- and postoperative 75 g oral glucose tolerance test, daily postoperative fasting plasma glucose, and haemoglobin A1c (HbA1c) pre-operation and at two, four and 12 weeks post operation.

RESULTS

After 12 weeks, the mean drop in HbA1c was 2.29 +/- 1.39 percent. The change in HbA1c at four (p is 0.039) and 12 (p is 0.005) weeks showed significant improvements. A significant decrease in diabetic medication usage was observed, with four (57 percent) patients not requiring medications within four weeks. Remission of DM was achieved in two (28.6 percent) patients within 12 weeks. Weight loss by various parameters was significant from two weeks onwards.

CONCLUSION

The cure rate of 28.6 percent and an improvement rate of 100 percent of T2DM in morbidly obese Asian patients within 12 weeks post operation are promising. Many patients discontinued their diabetic medications in the immediate postoperative period, even before significant weight loss had occurred, indicating that RYGBP has an effect on hormonal mechanisms that influence glucose homeostasis in the body.

Reduction of hexavalent uranium from organic complexes by sulfate- and iron-reducing bacteria

The influence of organic-hexavalent-uranium [U(VI)] complexation on U(VI) reduction by a sulfate-reducing bacterium (Desulfovibrio desulfuricans) and an iron-reducing bacterium (Shewanella alga) was evaluated. Four aliphatic ligands (acetate, malonate, oxalate, and citrate) and an aromatic ligand (tiron [4,5-dihydroxy-1,3-benzene disulfonic acid]) were used to study complexed-uranium bioavailability. The trends in uranium reduction varied with the nature and the amount of U(VI)-organic complex formed and the type of bacteria present. D. desulfuricans rapidly reduced uranium from a monodentate aliphatic (acetate) complex. However, reduction from multidentate aliphatic complexes (malonate, oxalate, and citrate) was slower. A decrease in the amount of organic-U(VI) complex in solution significantly increased the rate of reduction. S. alga reduced uranium more rapidly from multidentate aliphatic complexes than from monodentate aliphatic complexes. The rate of reduction decreased with a decrease in the amount of multidentate complexes present. Uranium from an aromatic (tiron) complex was readily available for reduction by D. desulfuricans, while an insignificant level of U(VI) from the tiron complex was reduced by S. alga. These results indicate that selection of bacteria for rapid uranium reduction will depend on the organic composition of waste streams.

Kelvin Helmholtz instability in strongly coupled Yukawa liquids

Using "first principles" molecular dynamics simulations Kelvin Helmholtz instability has been observed for the first time at the particle level in two-dimensional strongly coupled Yukawa liquids. At a given coupling strength Γ a subsonic shear profile is superposed on an equilibrated Yukawa liquid and instability is observed. Linear growth rates computed directly from MD simulations are seen to increase with strong coupling. Vortex-roll formation in the nonlinear regime is reported.

Solitary rectal ulcer syndrome: a case series

A retrospective analysis of the clinical profile, endoscopic features and management of 22 children (age 18 months-18 years) diagnosed as solitary rectal ulcer syndrome is presented. The majority (81.8%) were ≥8 years of age. Rectal bleeding was the presenting feature in all the children. Mucorrhea, constipation, tenesmus and rectal prolapse were observed in 77.3%, 63.6%, 59% and 13.6% children, respectively. Colonoscopy showed classical single rectal ulcer in 68.2% and multiple ulcers in 22.7%. Polypoidal and erosive lesions were documented in 4.5% each. The medical management comprised of bowel training and high fibre diet for all children. The other modalities included oral 5-amino salicylate (59%), sucralfate enema (4.5%) and rectal mesalamine in 9%. 64% children recovered and 13.6% had recurrence of symptoms.

Chronic abdominal pain in children

Chronic abdominal pain (CAP) continues to be a diagnostic and therapeutic challenge. It affects about 10% of school-going children and adolescents. Few Indian studies have reported an organic cause in 30%-40% of children with recurrent abdominal pain. In developing countries, parasitic infestations such as giardiasis and ascariasis are an important cause, of recurrent abdominal pain but their frequency has decreased over time. There is a paucity of data from India on the aetiology, epidemiology and management strategies for CAP, and there is no consensus on the clinical approach to this problem. We present a practical approach to CAP in children. The first step is to elicit a detailed history and do a thorough physical examination so as to categorize CAP according to the site of pain (epigastric, periumbilical or left lower quadrant), the predominant symptom associated with pain (dyspepsia, isolated pain or altered bowel habits) and to differentiate the pain as organic or functional based on the characteristics of pain and presence or absence of alarm signs. The second step is to do appropriate investigations, restricted to simple tests when functional pain is suspected (Level I) and more investigations (Level Ia) if there are alarm signs and pain appears to be organic in nature. Invasive investigations such as gastrointestinal endoscopy (Level II) may be reserved for those with possible organic pain. Level III investigations need to be done in a small percentage of children and include EEG, workup for food allergy and porphyria. The third step is management of organic CAP according to the aetiology, while for functional CAP the pharmacological and, rarely, psychological intervention is more difficult but should be done discreetly and tailored to the needs of the child.

Effect of external drive on strongly coupled Yukawa systems: a nonequilibrium molecular dynamics study

Using nonequilibrium molecular dynamics (MD) simulations behavior of three-dimensional (3D) Yukawa system has been studied in the presence of a small amplitude drive along one direction (say z[over ] ). This drive has the general form V=V_{0} cos(k_{L}z)Theta(t-t_{0}) , where Theta(t-t_{0}) is a Heaviside step function in time at t=t_{0} and k_{L}=2pi/L , L being the size of the system; V0 is considered small compared to average interparticle potential energy. In particular, a 3D equilibrated Yukawa crystal (bcc) near solid-liquid transition is subjected to an external drive at times t> or =t_{0} at the largest possible scale. For a given k_{L} it is observed that there exists a critical amplitude (V_{0};{c}) of the external drive below which the crystalline order is preserved and above which (V_{0}> or =V_{0};{c}) the transition from bcc to strongly coupled Yukawa liquid is observed. This critical amplitude (V_{0};{c}) is sensitive to the location of the Yukawa solid in the (kappa,Gamma) phase space. Various signatures of melting, transients, and steady state in the presence of this drive are elucidated using extensive MD diagnostics such as loss of long-range crystalline order, change in diffusion from subnormal to normal, and the fall of transversal shear peak in the Fourier transform of the velocity autocorrelation function. The mechanism of heating in the transient state is attributed to the local heating of the system where the forces are maximum. It is shown that these local hot regions dissipate heat into surrounding regions ultimately leading to a uniform temperature throughout the system. Ion streaming due to external field has been neglected.

Primary intestinal lymphangiectasia

Primary intestinal lymphangiectasia (PIL) is a rare disease of intestinal lymphatics presenting with hypoproteinemia, bilateral lower limb edema, ascites, and protein losing enteropathy. We report a series of 4 children from Chennai, India presenting with anasarca, recurrent diarrhea, hypoproteinemia and confirmatory features of PIL on endoscopy and histopathology.

Recurrent Kawasaki disease

We describe an infant who had recurrence of Kawasaki disease and responded to therapy with Intravenous Immune globulin (IVIG) and highlight the need for recognition of this vasculitis, which is being increasingly recognised in the Indian subcontinent.

Rhinocerebral mucormycosis in an adolescent with type 1 diabetes mellitus: case report

Rhinocerebral mucormycosis is a severe opportunistic infection affecting immunocompromised patients. A 14-year-old boy with rhino-orbito-cerebral mucormycosis and type 1 diabetes is described. He responded well to amphotericin B lipid complex followed by itraconazole.