Preferential electrostatic interactions of phosphatidic acid with arginines.

Phosphatidic acid (PA) is an anionic lipid that preferentially interacts with proteins in a diverse set of cellular processes such as transport, apoptosis, and neurotransmission. One such interaction is that of the PA lipids with the proteins of voltage-sensitive ion channels. In comparison to several other similarly charged anionic lipids, PA lipids exhibit much stronger interactions.

A lateral electric field inhibits gel-to-fluid transition in lipid bilayers.

We report evidence of lateral electric field-induced changes in the phase transition temperatures of lipid bilayers. Our atomic scale molecular dynamics simulations show that a lateral electric field increases the melting temperatures of DPPC, POPC and POPE bilayers. Remarkably, these shifts in the melting temperatures are only induced by lateral electric fields, and not normal electric fields.

Analysis of choroidal structure and vascularity indices with image binarization of swept source optical coherence tomography images: A prospective study of 460 eyes.

Purpose: To evaluate choroidal vascularity index (CVI) among normal subjects using image binarization of swept source optical coherence tomography (SS-OCT).

Materials And Methods: Four hundred and sixty eyes of 230 normal participants were included. Total circumscribed choroidal area, luminal area, stromal area (SA), and CVI were derived from SS-OCT scans using open-source software (ImageJ) with the modified Niblack method.

Intravitreal Ozurdex has no short term influence on choroidal thickness and vascularity index in eyes with diabetic macular edema: A pilot study.

Aim: To analyze choroidal parameters in eyes with diabetic macular edema (DME) treated with intravitreal Ozurdex.

Patients And Methods: Twenty eyes of 14 patients were included in this prospective study. Optical coherence tomography images were obtained before and 8-10 weeks after intravitreal Ozurdex injection; binarized and subfoveal choroidal thickness (SFCT) and choroidal vascularity index (CVI) were calculated.

Efficient Thin Polymer Coating as a Selective Thermal Emitter for Passive Daytime Radiative Cooling.

Radiative cooling to subambient temperatures can be efficiently achieved through spectrally selective emission, which until now has only been realized by using complex nanoengineered structures. Here, a simple dip-coated planar polymer emitter derived from polysilazane, which exhibits strong selective emissivity in the atmospheric transparency window of 8-13 μm, is demonstrated. The 5 μm thin silicon oxycarbonitride coating has an emissivity of 0.

Complimentary action of structured and unstructured domains of epsin supports clathrin-mediated endocytosis at high tension.

Membrane tension plays an inhibitory role in clathrin-mediated endocytosis (CME) by impeding the transition of flat plasma membrane to hemispherical clathrin-coated structures (CCSs). Membrane tension also impedes the transition of hemispherical domes to omega-shaped CCSs. However, CME is not completely halted in cells under high tension conditions.

Geometry of the nuclear envelope determines its flexural stiffness.

During closed mitosis in fission yeast, growing microtubules push onto the nuclear envelope to deform it, which results in fission into two daughter nuclei. The resistance of the envelope to bending, quantified by the flexural stiffness, helps determine the microtubule-dependent nuclear shape transformations. Computational models of envelope mechanics have assumed values of the flexural stiffness of the envelope based on simple scaling arguments.

Exploring the links between lipid geometry and mitochondrial fission: Emerging concepts.

Mitochondria, the double membrane-walled powerhouses of the eukaryotic cell, are also the seats of synthesis of two critical yet prevalent nonbilayer-prone phospholipids, namely phosphatidylethanolamine (PE) and cardiolipin (CL). Besides their established biochemical roles in the regulation of partner protein function, PE and CL are also key protagonists in the biophysics of mitochondrial membrane remodeling and dynamics. In this review, we address lipid geometry and behavior at the single-molecule level as well as their intimate coupling to whole organelle morphology and remodeling during the concerted events of mitochondrial fission.

Border Medicine: The Pediatric Cardiology Perspective.

Pediatric cardiology and cardiovascular surgery have witnessed significant advancements over the last two decades. In spite of this progress, congenital heart disease (CHD) still remains as one of the major causes of death in infants and young children in the United States. Many patient-related and patient-independent factors influence the outcomes in patients with CHD, one of which is the geographical location.

Mechanics of nuclear membranes.

Cellular nuclei are bound by two uniformly separated lipid membranes that are fused with each other at numerous donut-shaped pores. These membranes are structurally supported by an array of distinct proteins with distinct mechanical functions. As a result, the nuclear envelope possesses unique mechanical properties, which enables it to resist cytoskeletal forces.

Local, transient tensile stress on the nuclear membrane causes membrane rupture.

Cancer cell migration through narrow constrictions generates compressive stresses on the nucleus that deform it and cause rupture of nuclear membranes. Nuclear membrane rupture allows uncontrolled exchange between nuclear and cytoplasmic contents. Local tensile stresses can also cause nuclear deformations, but whether such deformations are accompanied by nuclear membrane rupture is unknown.

Geometric instability catalyzes mitochondrial fission.

The mitochondrial membrane undergoes extreme remodeling during fission. While a few membrane-squeezing proteins are recognized as the key drivers of fission, there is a growing body of evidence that strongly suggests that conical lipids play a critical role in regulating mitochondrial morphology and fission. However, the mechanisms by which proteins and lipids cooperate to execute fission have not been quantitatively investigated.

Vesicle adhesion reveals novel universal relationships for biophysical characterization.

Adhesion plays an integral role in diverse biological functions ranging from cellular transport to tissue development. Estimation of adhesion strength, therefore, becomes important to gain biophysical insight into these phenomena. In this study, we use curvature elasticity to present non-intuitive, yet remarkably simple, universal relationships that capture vesicle-substrate interactions.

Clathrin polymerization exhibits high mechano-geometric sensitivity.

How tension modulates cellular transport has become a topic of interest in the recent past. However, the effect of tension on clathrin assembly and vesicle growth remains less understood. Here, we use the classical Helfrich theory to predict the energetic cost that clathrin is required to pay to remodel the membrane at different stages of vesicle formation.

Ultradonut topology of the nuclear envelope.

The nuclear envelope is a unique topological structure formed by lipid membranes in eukaryotic cells. Unlike other membrane structures, the nuclear envelope comprises two concentric membrane shells fused at numerous sites with toroid-shaped pores that impart a "geometric" genus on the order of thousands. Despite the intriguing architecture and vital biological functions of the nuclear membranes, how they achieve and maintain such a unique arrangement remains unknown.

An unresolved LINC in the nuclear envelope.

The nuclear envelope segregates the nucleoplasm from the cytoplasm and is a key feature of eukaryotic cells. Nuclear envelope architecture is comprised of two concentric membrane shells which fuse at multiple sites and yet maintain a uniform separation of 30-50 nm over the rest of the membrane. Studies have revealed the roles for numerous nuclear proteins in forming and maintaining the architecture of the nuclear envelope.

Endocytic proteins drive vesicle growth via instability in high membrane tension environment.

Clathrin-mediated endocytosis (CME) is a key pathway for transporting cargo into cells via membrane vesicles; it plays an integral role in nutrient import, signal transduction, neurotransmission, and cellular entry of pathogens and drug-carrying nanoparticles. Because CME entails substantial local remodeling of the plasma membrane, the presence of membrane tension offers resistance to bending and hence, vesicle formation. Experiments show that in such high-tension conditions, actin dynamics is required to carry out CME successfully.

Dimorphic Mandibular canines in gender determination in Moradabad population of Western Uttar Pradesh.

Background And Objectives: Among morphological characteristics that differentiate a male from a female, tooth size has also been evaluated in various populations for its applicability in anthropologic and forensic investigations to identify the gender from dental remains. The present study was undertaken to investigate the accuracy of mesio-distal width of the mandibular canines, inter-canine arch width, and Mandibular Canine Index (MCI) with which gender can be differentiated in Moradabad population and to correlate the results with other available data.

Materials And Methods: A cross-sectional study was conducted on the casts of 30 males and 30 females between the age group of 19-30 years.

Oral candidiasis: An overview.

Candida is the shortened name used to describe a class of fungi that includes more than 150 species of yeast. In healthy individuals, Candida exists harmlessly in mucus membranes such as your ears, eyes, gastrointestinal tract, mouth, nose, reproductive organs, sinuses, skin, stool and vagina, etc. It is known as your "beneficial flora" and has a useful purpose in the body.

Cross-sectional serologic assessment of immunity to poliovirus infection in high-risk areas of northern India.

Introduction: The objectives of this survey were to assess the seroprevalence of antibodies to poliovirus types 1 and 3 and the impact of bivalent (types 1 and 3) oral poliovirus vaccine (bOPV) use in immunization campaigns in northern India.

Methods: In August 2010, a 2-stage stratified cluster sampling method identified infants aged 6-7 months in high-risk blocks for wild poliovirus infection. Vaccination history, weight and length, and serum were collected to test for neutralizing antibodies to poliovirus types 1, 2, and 3.

Peripheral giant cell granuloma: a case report.

Peripheral giant cell granuloma (PGCG) is a benign inflammatory hyperplastic lesion of unknown etiology that occurs in the gingiva or alveolar ridge. It normally manifests as a soft tissue nodule, purplish-red in color, consisting of multinucleated giant cells in a background of mononuclear stromal cells and extravasated red blood cells. This article presents a case of a 75-year-old man whose chief complaint was painless swelling in the posterior mandibular region.

Anisotropic spontaneous curvatures in lipid membranes.

Symmetry restrictions due to fluidity require the strain energy in the Helfrich theory of lipid membranes to be locally isotropic in nature. Although this framework is suitable for modeling the interaction of membranes with proteins that generate spherical curvature such as clathrin, there are other important membrane-bending proteins such as BIN-amphiphysin-Rvs proteins that form a cylindrical coat with different curvatures in the longitudinal and the circumferential directions. In this work, we present a detailed mathematical treatment of the theory of lipid membranes incorporating anisotropic spontaneous curvatures.

Small scale membrane mechanics.

Large scale changes to lipid bilayer shapes are well represented by the Helfrich model. However, there are membrane processes that take place at smaller length scales that this model cannot address. In this work, we present a one-dimensional continuum model that captures the mechanics of the lipid bilayer membrane at the length scale of the lipids themselves.

Interaction between surface shape and intra-surface viscous flow on lipid membranes.

The theory of intra-surface viscous flow on lipid bilayers is developed by combining the equations for flow on a curved surface with those that describe the elastic resistance of the bilayer to flexure. The model is derived directly from balance laws and augments an alternative formulation based on a variational principle. Conditions holding along an edge of the membrane are emphasized, and the coupling between flow and membrane shape is simulated numerically.

Gorlin-goltz syndrome: case report of a rare hereditary disorder.

Introduction. Gorlin-Goltz syndrome is an inherited autosomal dominant disorder with complete penetrance and extreme variable expressivity. Case Report.