[Work-Family Policy and Family Friendly Society] Care Work, Gender Roles and Family Policies between Social Reproduction and the Market

Christa Wichterich 가정과삶의질학회 2011 한국가정관리학회 학술발표대회 자료집 Vol.2011 No.5

Review : How Leptin Controls the Drive to Eat

( Christa M. Patterson ),( Martin G. Myers Jr ) 대한비만학회 2015 The Korean journal of obesity Vol.24 No.2

A complex set of brain based systems modulate feeding to maintain constant body weight. The adipose derived-hormone, leptin, plays a crucial role in this control by acting on diverse leptin receptor (LepRb)-expressing neurons in the hypothalamus and brainstem to modify behavior and metabolism. In addition to controlling energy expenditure and satiety, leptin controls motivation and the reward value of food by regulating two interconnected systems: hypocretin (HCRT) neurons and the mesolimbic dopamine (MLDA) system. Modest/acute decreases in leptin levels, as associated with mild caloric restriction, increase MLDA activity and overall food-seeking behavior; in contrast, severe starvation or complete leptin deficiency blunt MLDA activity, along with motivation and associated behaviors. Lateral hypothalamic (LHA) LepRb neurons project to dopamine (DA) neurons in the ventral tegmental area, where neurotensin (NT) release augments MLDA function; these LepRbNT cells also innervate HCRT neurons to control Hcrt expression and inhibit HCRT neurons. Ablation of LepRb in these cells abrogates the control of HCRT cells by leptin and decreases activity and MLDA function. We propose that this neural pathway regulates the MLDA, activity, and motivation in response to leptin and nutritional status.

Protective Role of 360° Laser Retinopexy in Patients with Rhegmatogenous Retinal Detachment: a Systematic Review and Meta-analysis

Christa Soekamto,Edward R Chu,Daniel A Johnson,Jeong-Hyeon Sohn,Sepehr Bahadorani 대한안과학회 2021 Korean Journal of Ophthalmology Vol.35 No.3

Purpose: Visual impairment from retinal re-detachment could be debilitating. The aim of this review is to evaluate the role of 360° laser retinopexy on success rate of rhegmatogenous retinal detachment (RRD) repair by a meta-analysis study. Methods: The PubMed, Scopus, and the Cochrane Library databases were searched comprehensively from the date of database inception to January 2021, evaluating the role of 360° laser retinopexy in visual and anatomical success rate of RRD repair. This review was conducted based on the preferred reporting items for systematic review and meta-analysis (PRISMA) protocols. Results: Among 202 articles screened for eligibility, six studies were found to be eligible for inclusion in our final analysis. Our meta-analysis demonstrates that prophylactic treatment with circumferential laser photocoagulation has no significant effect on the initial rate of retinal re-detachment or final best-corrected visual acuity following pars plana vitrectomy repair of RRD. Subgroup analysis of studies (n = 3) with 23-gauge pars plana vitrectomy, however, favors attachment rate in patients undergoing 360° prophylactic laser treatment. Conclusions: Three hundred and sixty degree laser retinopexy appears to have favorable outcomes in patients undergoing 23-gauge retinal detachment repair. This protective effect, however, is not apparent with inclusion of 20-gauge vitrectomy studies.

관점과 언어구조

Durscheid, Christa 한국독어독문학회 1999 獨逸文學 Vol.72 No.1

Body-centered cubic phase in 3-arm star mesogens: a torsional tapping AFM and GISAXS study

Weber, Christa H. M.,Liu, Feng,Zeng, Xiang-bing,Ungar, Goran,Mullin, Nic,Hobbs, Jamie K.,Jahr, Michael,Lehmann, Matthias The Royal Society of Chemistry 2010 SOFT MATTER Vol.6 No.21

<P>The mode of liquid crystal (LC) self-assembly of asymmetric three-arm star oligobenzoate mesogens has been investigated by torsional tapping mode AFM imaging, and by bulk and grazing-incidence X-ray diffraction. It was confirmed that the cubic liquid crystal phase has <I>Im</I>3&cmb.macr;<I>m</I> symmetry and established that it consists of spherical aggregates arranged on a body-centered lattice, rather than having a bicontinuous structure. Molecular simulation suggests that, in spite of their perceived rigidity, the oligobenzoate mesogens are folded, often sharply, within the supramolecular spheres, and that they act effectively as conical objects. The recently introduced torsional tapping AFM technique has allowed high resolution and contrast to be obtained from the soft mobile surface of the samples, showing the (110) plane of highly ordered supramolecular spheres. Notably the fine structure of the observed steps reveals that nearly isolated micelles still preserve their integrity. Finally, the equilibrium habits of the cubic LC droplets were shown by optical microscopy to be polyhedral with crystallographic facets, rather than spherical. This suggests that the air–LC interface is below the roughening transition temperature, which is attributed to the whole micelles rather than the isolated molecules acting as the interacting units.</P> <P>Graphic Abstract</P><P>A combination of torsional tapping atomic force microscopy and X-ray diffraction confirmed a cubic liquid crystal phase in 3-arm star mesogens, displaying faceted gem-like droplets and stable isolated self-assembled micelles at surface steps. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0sm00420k'> </P>

Phytochemical and toxicological evaluations of Prosopis africana (GUILL. and PERR.) extract on albino wistar rats

Obode Okukwe Christa,Adebayo Abiodun Humphrey,Li Chunyang 한국독성학회 2021 Toxicological Research Vol.37 No.2

In this study, we investigated the phytochemical and toxicological impacts of the ethanol leaf extract of Prosopis africana in albino rats. Preliminary phytochemical analysis was done using established methods. Acute and 28-day sub-chronic toxicity evaluations of the extract were carried out in wistar rats. Five groups made up of 8 rats per group were used and treated with 500, 1000, 1500 and 2000 mg/kg b.wt. respectively; while the control group received 1 ml of 10% Tween-20 solution. Phytochemicals detected include tannins, saponins, flavonoids, alkaloids, anthocyanin, quinones, terpenoids and steroids. There were no signs of toxicity in the acute toxicity study neither was any death recorded. Weight loss and death were recorded after 18 days of treatment in groups treated with 1500 and 2000 mg/kg b.wt. No significant alteration of haematological parameters was observed, however increased WBC count was recorded. Liver and kidney function parameters were significantly (p < 0.05) reduced, while significant (p < 0.05) increase in triglycerides with lowered cholesterol was seen when compared with the control group. Histological evaluations of the liver, kidney, heart and testicular tissues revealed normal sections in majority of the animals; however, mild vascular congestions were observed at random doses (liver and heart at 1500 mg/kg b.wt.; kidney at 500 mg/kg b.wt.). Our study shows that ethanol leaf extract of P. africana would probably not cause significant toxic effects as indicated by haematological and biochemical parameters. However, there may be need to apply caution in its use at high doses given that death occurred at 1500 mg/kg b.wt. during the repeat-dose toxicity study.

Ultra-fine Grained and Dispersion-strengthened Titanium Materials Manufactured by Spark Plasma Sintering

Handtrack Dirk,Sauer Christa,Kieback Bernd 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

Ultra-fine grained and dispersion-strengthened titanium materials (Ti-Si, Ti-C, Ti-Si-C) have been produced by high energy ball milling and spark plasma sintering (SPS). Silicon or/and carbon were milled together with the titanium powder to form nanometer-sized and homogeneously distributed titanium silicides or/and carbides as dispersoids, that should prevent grain coarsening during the SPS compaction and contribute to strengthening of the material. The microstructures and the mechanical properties showed that strength, hardness and wear resistance of the sintered materials have been significantly improved by the mechanisms of grain refinement and dispersion strengthening. The use of an organic fluid as carrier of the dispersoid forming elements caused a significant increase in ductility.

Nanodispersion-Strengthened Metallic Materials

Weissgaerber, Thomas,Sauer, Christa,Kieback, Bernd The Korean Powder Metallurgy Institute 2002 한국분말재료학회지 (KPMI) Vol.9 No.6

Dispersions of non-soluble ceramic particles in a metallic matrix can enhance the strength and heat resistance of materials. With the advent of mechanical alloying it became possible to put the theoretical concept into practice by incorporating very fine particles in a flirty uniform distribution into often oxidation- and corrosion- resistant metal matrices. e.g. superalloys. The present paper will give an overview about the mechanical alloying technique as a dry, high energy ball milling process for producing composite metal powders with a fine controlled microstructure. The common way is milling of a mixture of metallic and nonmetallic powders (e.g. oxides. carbides, nitrides, borides) in a high energy ball mill. The heavy mechanical deformation during milling causes also fracture of the ceramic particles to be distributed homogeneously by further milling. The mechanisms of the process are described. To obtain a homogeneous distribution of nano-sized dispersoids in a more ductile matrix (e.g. aluminium-or copper based alloys) a reaction milling is suitable. Dispersoid can be formed in a solid state reaction by introducing materials that react with the matrix either during milling or during a subsequent heat treatment. The pre-conditions for obtaining high quality materials, which require a homogeneous distribution of small dis-persoids, are: milling behaviour of the ductile phase (Al, Cu) will be improved by the additives (e.g. graphite), homogeneous introduction of the additives into the granules is possible and the additive reacts with the matrix or an alloying element to form hard particles that are inert with respect to the matrix also at elevated temperatures. The mechanism of the in-situ formation of dispersoids is described using copper-based alloys as an example. A comparison between the in-situ formation of dispersoids (TiC) in the copper matrix and the milling of Cu-TiC mixtures is given with respect to the microstructure and properties, obtained.

Properties of Spacers in Semi-Rigid Linear Polymers

Rita Baxmann,Michael Hess,Christa Kreuzburg,Ralf Woelke,Wiebren S. Veeman 한국고분자학회 1998 한국고분자학회 학술대회 연구논문 초록집 Vol.1998 No.10

pH and magnetic field sensitive folic acid conjugated protein–polyelectrolyte complex for the controlled and targeted delivery of 5-fluorouracil

T.S. Anirudhan,J. Christa,Binusreejayan 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.57 No.-

In the present study, a magnetic protein–polyelectrolyte complex of casein coated iron oxidenanoparticles and folic acid conjugated chitosan-graft-poly(2-dimethylaminoethyl methacrylate) wasprepared for the delivery of an anticancer drug, 5-fluorouracil (5-FU) and characterized using FTIR, XRD,VSM, FESEM, TEM, DLS and zeta potential studies. Sustained and controlled release of 5-FU was observedat acidic pH 5.0. Drug release kinetic studies indicated both swelling and diffusion controlled release. Invitro cytotoxicity studies revealed the low toxicity of the prepared nano drug carrier towards normal cellsand folate receptor targeting efficiency of 5-FU loaded carrier towards cancer cells.