Dimensional Issues in Stereolithography

New stereolithography photopolymers have recently been introduced that provide a wider range of functional properties similar to those of high-density polyethylene. One of the important criteria for these materials is the dimensional accuracy and stability in end-use applications as mold masters or the actual functional parts. This work investigates the dimensional stability of one of these new materials with varying amounts of exposure during build. The effect of aging on the part dimensions is reported. The result of environmental humidity extremes at ambient temperature on part dimensions is investigated and compared for parts made from two different families of stereolithography resins, namely DuPont Somos® 7100 and Somos® 8100.Mechanical Engineerin

Heparin affinity tag and application thereof

In one aspect, affinity tags for recombinant protein purification are described herein which, in some embodiments, can mitigate or overcome disadvantages of prior affinity tag systems. In some embodiments, for example, affinity tags described herein permit efficient elution of desired recombinant proteins with simplified solution systems, such as alkali metal salt solutions. An affinity tag described herein comprises an amino acid sequence including a repeating amino acid unit of BXXXBXX, wherein B is an amino acid selected from the group consisting of histidine, lysine and arginine and X is an amino acid selected from the group consisting of amino acids other than histidine, lysine and arginine

Heparin affinity tag and applications thereof

In one aspect, affinity tags for recombinant protein purification are described herein which, in some embodiments, can mitigate or overcome disadvantages of prior affinity tag systems. In some embodiments, for example, affinity tags described herein permit efficient elution of desired recombinant proteins with simplified solution systems, such as alkali metal salt solutions. An affinity tag described herein comprises an amino acid sequence including a repeating amino acid unit of BXXXBXX, wherein B is an amino acid selected from the group consisting of histidine, lysine and arginine and X is an amino acid selected from the group consisting of amino acids other than histidine, lysine and arginin

Engineered FGF compositions and methods of use thereof

The present invention relates to the development of stable mutants of FGF-1 and FGF-2. In particular, it relates to novel engineered FGF-1 and FGF-2 polypeptides as well as polynucleotides, DNA constructs, and vectors encoding such polypeptides. In another aspect, pharmaceutical compositions and hydrogels including the disclosed polypeptides, polynucleotides, DNA constructs, and vectors are provided. In a still further aspect, methods of treating conditions using the compositions disclosed herein are provided

Stereolithographic Injection Molds for Direct Tooling

The use of stereolithographic core and cavity sets in low volume injection molding is experiencing steady growth. The use of plastic instead of metal molds raises several issues in terms ofmold handling, material injection and process cycle requirements. This study focuses on identifying and understanding these issues and optimizing them for low volume direct tooling applications. Some experimental observations are presented using DuPont Somos® epoxy photopolymers and representative mold geometries which identify the critical mold properties that influence mold life and the injection molded part quality.Mechanical Engineerin

Prevalence and socio-demographic association of depression, anxiety and stress among university students

Prevalence of Stress, anxiety and depression has been identified to be high among university students which may affect their social and professional lives. The study aims at assessing the prevalence of stress, anxiety and depression among university students and analyzes their association with gender, ethnicity and area of upbringing. The study also intends to identify their coping strategies. This was a cross sectional study utilizing validated questionnaires. It was conducted among a total of 143 university students in Johar bahru. The questionnaires used were the socio-demographic questionnaire, DAAS-21 questionnaire and Brief coping strategy Questionnaire. Data was analyzed using SPSS software. Descriptive statistics was used. The mean age of the students under the study was 25.02±8.6 years. Depression was seen in 62.2% of the students and anxiety and stress were seen in 78.3% and 55.9 % students respectively. Depression, anxiety and stress were found more in females than males. Anxiety was more in Malays and depression and stress was more among other ethnic groups. Anxiety and depression were seen more in students with a rural upbringing and stress in students with a urban upbringing. There was no significant association between depression, anxiety, stress and gender, ethnicity and area of upbringing. The mean score for the common coping strategies employed which was acceptance, positive reframing and self distraction were 2.8±0.9, 2.8±1.0, 2.8±1.0 respectively. Prevalence of anxiety was more compared to stress or depression. Students used active coping Strategies to cope with stress

Hepatoprotective activity of six polyherbal formulations in CCl₄-induced liver toxicity in mice

257-263To evaluate pretreatment of six polyherbal liquid formulations (PLFs) commercially available in India, on CCl4-induced liver injury, Swiss albino mice were treated for 7 days with distilled water or PLFs (2.6 and 5.2 ml/kg body weight/day, po) followed by single sc injection of 50% (v/v) CCl4 in arachis oil at a dose of 1ml/kg. The serum biochemical parameters such as alanine transaminases, aspartate transaminases and alkaline phosphatase were estimated. Phenobarbitone-induced sleeping time and liver histopathology were also carried out. CCl4-treated animals showed significant increase in the levels of liver enzymes, phenobarbitone-induced sleeping time and revealed fatty changes and centrizonal necrosis on histological examination of liver indicating hepatic damage. When pretreated with PLFs at a dose of 5.2 ml/kg body weight/day, the CCl4-induced changes were significantly reversed. The pretreatment with PLFs can prevent acute liver damage induced by CCl4 only at a higher dose. Therefore, it is suggested that a dose adjustment of these PLFs may be necessary for their optimal effects in human liver diseases

Vibrational spectra and quantum chemical investigations on nicotinium nitrate monohydrate single crystal for anti bacterial studies

Nicotinium Nitrate Monohydrate (NNM) was grown by slow evaporation method. The arrangment of the molecules and hydrogen bonding intractionsin the grown crystal were analyzed using single crystal XRD. The structure, functional groups (vibrational analysis) and electronic properties (Mulliken and HOMO-LUMO analysis) were calculated by the density functional theory (DFT)/B3LYP/wB97XD method using 6–311++G (d,p) basis set. Also, the binding energy and the effect of basis set superposition error (BSSE) on the ring motifs have been investigated. The intermolecular interactions and charge delocalization density of NNM crystal have been analyzed using NBO 3.1 program. The strength of intermolecular interaction was further analyzed by 3D Hirshfeld surface analysis using fingerprint plot. Improved solubility of the title crystal NNM shows an enhanced physio-chemical activity compared to pure vitamin B3 (Nicotinic acid). The antibacterial activity of NNM crystal increased against Staphylococcus aureus a gram-positive bacteria when compared with pure nicotinic acid