A REVIEW ON: ATRIGEL–THE MAGICAL TOOL

The widely effective and most common form of drug delivery is parenteral administration for active drug substances with poor bio-availability and the drugs with a narrow therapeutic index. Though parenteral administration of drug is often critical and associated with problems such as limited number of acceptable excipients, stringent requirements of aseptic production process, safety issues, patient noncompliance. Still this route maintains its value due to special advantages like quicker onset of action in case of emergency, target the drug quickly to desired site of action, prevention of first pass metabolism etc. The application of advanced drug delivery technology to parenteral administration lead to development of liposomes, nanosuspensions, solid implants etc. to overcome limitations of conventional parenteral delivery. Solid implants are reported to produce very reproducible release profiles. However, because of their size, they require surgical implantation or the use of large trochars to administer the product. Delivery systems consisting of microparticles can be injected into the body using conventional needles and syringes and have been the most widely accepted biodegradable polymer system for parenteral use. However, the manufacturing processes for microparticles are often complex and difficult to control leading to batch-to-batch product non uniformity. These methods of administration often limit the product's market potential due to patient and physician acceptance issues. Therefore, a delivery system that combines the simplicity and reliability of solid implant devices alongwith convenience and ease of administration of microparticles is desired. In situ gel forming systems represent a desired alternate. This article gives the idea about In situ gel forming system to provide drug release in sustained release manner

Perspectives of Ramsey Schemes Based on High-Order Harmonics for High-Resolution XUV Spectroscopy

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Mesure statistique de la résistance de contact d’une grille sérigraphiée pour cellules solaires au silicium multicristallin

La métallisation par sérigraphie est une des étapes les plus importantes dans la technologie d’élaboration des cellules solaires pour une production à grande échelle. Néanmoins, elle demeure dépendante de plusieurs paramètres variables. Pour le silicium multi cristallin, tout changement dans le procédé de réalisation des cellules solaires influence directement l’optimisation du profil de recuit de la métallisation par sérigraphie. Les plaquettes de silicium multi cristallin subissent toutes les étapes classiques de réalisation des cellules solaires comme le nettoyage chimique et la décontamination, une diffusion au phosphore et le dépôt du nitrure de silicium SiNx par PECVD (Plasma Enhanced Chemical Vapor Deposition). Il y a juste le dépôt du contact Argent Ag sur la face avant de la plaquette. Nous avons utilisé la pâte de sérigraphie Ag Ferro 3349. La grille métallique comporte six (06) motifs TLM (Transfer Length Method) pour les mesures de la résistance de contact. Le principal but de ce travail est le contrôle de la qualité du contact Ag/SiNx/n+-Si dans les cellules solaires au silicium multicristallin. Les mesures TLM révèlent une cartographie des valeurs de la résistance de contact pour chaque température. Le profil optimal de température de recuit est autour de 750 °C

FASILITASI KEBUTUHAN ATAS PENGHARGAAN DIRI UNTUK MENDUKUNG PEMBELAJARAN KIMIA DI ERA SOCIETY 5.0

Indonesia has entered Revolution 4.0 where technology has become the basis of human life. Slowly but sure, Indonesia is entering the Society 5.0 Era characterized by (1) freedom; (2) customization; (3) scrutiny; (4) integrity; (5) entertainment; (6) speed; and (7) innovation. Society 5.0 offers a human-centered society that makes a balance between economic progress and solving social problems through a highly connected system between the virtual and real world. According to the Japanese prime minister, Shinzo Abe, explained in the World Economic Forum (WEF) that the Society 5.0 is no longer about capital, but data that connects and mobilizes all fields such as education and health that must fill the gap in society. At this time, we will propose the role of education in the Era of Society 5.0, especially related to chemistry learning that facilitates the need for self-esteem. Human needs are the same, such as basic needs, described as the hierarchy of needs by Maslow's Theory. The need for self-esteem is one of the needs of human psychology that must be fulfilled, especially for students to face the challenges of the Era of Society 5.0 to enrich chemistry learning as a need for a more meaningful life. The participants are 34 Grade X students from Natural Science Class 2 of Public High School (SMA NEGERI) 18 Jakarta. The data are pretest by Likert Scale Questionnaire, and posttest by a simple chemistry learning module with topic acid-base equilibrium.   Keywords: Society 5.0; need for self-esteem; chemistry.Indonesia has entered Revolution 4.0 where technology has become the basis of human life. Slowly but sure, Indonesia is entering the Society 5.0 Era characterized by (1) freedom; (2) customization; (3) scrutiny; (4) integrity; (5) entertainment; (6) speed; and (7) innovation. Society 5.0 offers a human-centered society that makes a balance between economic progress and solving social problems through a highly connected system between the virtual and real world. According to the Japanese prime minister, Shinzo Abe, explained in the World Economic Forum (WEF) that the Society 5.0 is no longer about capital, but data that connects and mobilizes all fields such as education and health that must fill the gap in society. At this time, we will propose the role of education in the Era of Society 5.0, especially related to chemistry learning that facilitates the need for self-esteem. Human needs are the same, such as basic needs, described as the hierarchy of needs by Maslow's Theory. The need for self-esteem is one of the needs of human psychology that must be fulfilled, especially for students to face the challenges of the Era of Society 5.0 to enrich chemistry learning as a need for a more meaningful life. The participants are 34 Grade X students from Natural Science Class 2 of Public High School (SMA NEGERI) 18 Jakarta. The data are pretest by Likert Scale Questionnaire, and posttest by a simple chemistry learning module with topic acid-base equilibrium.   Keywords: Society 5.0; need for self-esteem; chemistry

Statics, metastable states and barriers in protein folding: A replica variational approach

Protein folding is analyzed using a replica variational formalism to investigate some free energy landscape characteristics relevant for dynamics. A random contact interaction model that satisfies the minimum frustration principle is used to describe the coil-globule transition (characterized by T_CG), glass transitions (by T_A and T_K) and folding transition (by T_F). Trapping on the free energy landscape is characterized by two characteristic temperatures, one dynamic, T_A the other static, T_K (T_A> T_K), which are similar to those found in mean field theories of the Potts glass. 1)Above T_A, the free energy landscape is monotonous and polymer is melted both dynamically and statically. 2)Between T_A and T_K, the melted phase is still dominant thermodynamically, but frozen metastable states, exponentially large in number, appear. 3)A few lowest minima become thermodynamically dominant below T_K, where the polymer is totally frozen. In the temperature range between T_A and T_K, barriers between metastable states are shown to grow with decreasing temperature suggesting super-Arrhenius behavior in a sufficiently large system. Due to evolutionary constraints on fast folding, the folding temperature T_F is expected to be higher than T_K, but may or may not be higher than T_A. Diverse scenarios of the folding kinetics are discussed based on phase diagrams that take into account the dynamical transition, as well as the static ones.Comment: 41 pages, LaTeX, 9 EPS figure

Reply to Comment on "Criterion that Determines the Foldability of Proteins"

We point out that the correlation between folding times and $\sigma = (T_{\theta } - T_{f})/T_{\theta }$ in protein-like heteropolymer models where $T_{\theta }$ and $T_{f}$ are the collapse and folding transition temperatures was already established in 1993 before the other presumed equivalent criterion (folding times correlating with $T_{f}$ alone) was suggested. We argue that the folding times for these models show no useful correlation with the energy gap even if restricted to the ensemble of compact structures as suggested by Karplus and Shakhnovich (cond-mat/9606037).Comment: 6 pages, Latex, 2 Postscript figures. Plots explicitly showing the lack of correlation between folding time and energy gap are adde

An Analytical Approach to the Protein Designability Problem

We present an analytical method for determining the designability of protein structures. We apply our method to the case of two-dimensional lattice structures, and give a systematic solution for the spectrum of any structure. Using this spectrum, the designability of a structure can be estimated. We outline a heirarchy of structures, from most to least designable, and show that this heirarchy depends on the potential that is used.Comment: 16 pages 4 figure

The RCK2 domain of the human BKCa channel is a calcium sensor

Large conductance voltage and Ca2+-dependent K+ channels (BKCa) are activated by both membrane depolarization and intracellular Ca2+. Recent studies on bacterial channels have proposed that a Ca2+-induced conformational change within specialized regulators of K+ conductance (RCK) domains is responsible for channel gating. Each pore-forming α subunit of the homotetrameric BKCa channel is expected to contain two intracellular RCK domains. The first RCK domain in BKCa channels (RCK1) has been shown to contain residues critical for Ca2+ sensitivity, possibly participating in the formation of a Ca2+-binding site. The location and structure of the second RCK domain in the BKCa channel (RCK2) is still being examined, and the presence of a high-affinity Ca2+-binding site within this region is not yet established. Here, we present a structure-based alignment of the C terminus of BKCa and prokaryotic RCK domains that reveal the location of a second RCK domain in human BKCa channels (hSloRCK2). hSloRCK2 includes a high-affinity Ca2+-binding site (Ca bowl) and contains similar secondary structural elements as the bacterial RCK domains. Using CD spectroscopy, we provide evidence that hSloRCK2 undergoes a Ca2+-induced change in conformation, associated with an α-to-β structural transition. We also show that the Ca bowl is an essential element for the Ca2+-induced rearrangement of hSloRCK2. We speculate that the molecular rearrangements of RCK2 likely underlie the Ca2+-dependent gating mechanism of BKCa channels. A structural model of the heterodimeric complex of hSloRCK1 and hSloRCK2 domains is discussed

Coarse grained description of the protein folding

We consider two- and three-dimensional lattice models of proteins which were characterized previously. We coarse grain their folding dynamics by reducing it to transitions between effective states. We consider two methods of selection of the effective states. The first method is based on the steepest descent mapping of states to underlying local energy minima and the other involves an additional projection to maximally compact conformations. Both methods generate connectivity patterns that allow to distinguish between the good and bad folders. Connectivity graphs corresponding to the folding funnel have few loops and are thus tree-like. The Arrhenius law for the median folding time of a 16-monomer sequence is established and the corresponding barrier is related to easily identifiable kinetic trap states.Comment: REVTeX, 9 pages, 15 EPS figures, to appear in Phys. Rev.

Localization transition of random copolymers at interfaces

We consider adsorption of random copolymer chains onto an interface within the model of Garel et al. Europhysics Letters 8, 9 (1989). By using the replica method the adsorption of the copolymer at the interface is mapped onto the problem of finding the ground state of a quantum mechanical Hamiltonian. To study this ground state we introduce a novel variational principle for the Green's function, which generalizes the well-known Rayleigh-Ritz method of Quantum Mechanics to nonstationary states. Minimization with an appropriate trial Green's function enables us to find the phase diagram for the localization-delocalization transition for an ideal random copolymer at the interface.Comment: 5 page