bluuebunny/crossref_metadata_2025_split huggingface dataset:
Xanthopterin in the Oriental Hornet (Vespa orientalis): Light Absorbance Is Increased with Maturation of Yellow Pigment Granules
Authors: Plotkin Marian , Volynchik Stanislav , Ermakov Natalya Y. , Benyamini Avishai , Boiko Yulia , Bergman David J. , Ishay Jacob S. 
Published: February 2009

AbstractThe Oriental hornet bears both brown and yellow colors on its cuticle. The brown component is contributed by the pigment melanin, which is dispersed in the brown cuticle and provides protection against insolation, while the yellow‐colored part contains within pockets in the cuticle granules possessing a yellow pigment. These yellow granules (YG) are formed about 2 days prior to eclosion of the imago, and their production continues for about 3 days posteclosion. Xanthopterin is the main component of the granule and lends it its yellow color. Xanthopterin produces a characteristic excitation/emission maximum at 386/456 nm. Characterization by use of mass spectrometry showed the compound to have a molecular ion of 179, as expected from xanthopterin. Spectroscopic examination of the absorption of an entire stripe of yellow cuticle in the course of its metamorphosis revealed that the absorption steadily increases throughout the process to a maximal level of absorption about 3 days posteclosion. In the absence of the YG, the cuticle is permeable to the passage of all wavelengths within the visible range and to the UV range (290–750 nm) in all age groups of hornets. The newly ecloded hornets depart the nest to engage in activities requiring exposure to insolation only as the process of granule formation terminates, namely, when the layer of YG in the cuticle suffices to absorb all the harmful UV radiation.
Surface Charge Changes upon Formation of the Signaling State in Visual Rhodopsin†
Authors: Möller Martina , Alexiev Ulrike 
Published: February 2009

AbstractThe cytoplasmic surface of G protein‐coupled receptors plays a central role for activation and deactivation of the receptor. To understand the molecular mechanisms which underlie these processes, we determined the surface charge density and its changes upon activation directly at the cytoplasmic surface of bovine rhodopsin and correlated these changes with key events in receptor activation. The surface charge density was calculated from the ionic strength dependence of the apparent pKa of the surface‐bound pH‐indicator dye fluorescein according to the Gouy‐Chapman theory. The surface charge density at pH 6.5 changes by 0.8 ± 0.2 elementary charge/1000 Å2 in rod outer segment disk membranes and by 0.4 ± 0.2 elementary charge/1000 Å2 in rhodopsin/dodecylmaltoside micelles upon formation of the active metarhodopsin‐II state. By comparison of these surface charge density values determined with and without the native lipid environment, we calculated the charge change to about 1 elementary charge/cytoplasmic rhodopsin surface. The more positive surface charge density in metarhodopsin‐II decreases back to the dark state level of σ = −2.0 ± 0.2 elementary charges/1000 Å2 in the opsin state, providing further evidence that the cytoplasmic surface properties after metarhodopsin‐II decay resemble almost those of the dark state.
Structural Characterization of a Zinc High‐affinity Binding Site in Rhodopsin†
Authors: Toledo Darwin , Cordomí Arnau , Proietti Maria Grazia , Benfatto Maurizio , Del Valle Luis J. , Pérez Juan J. , Garriga Pere , Sepulcre Francesc 
Published: February 2009

AbstractFor the first time to our knowledge, X‐ray absorption spectroscopy (XAS) has been used to investigate the environment of putative Zn2+ binding sites in rhodopsin. We studied native purified nondeionized rhodopsin without any further addition of Zn2+, as well as with 1.5 mol of Zn2+—as zinc chloride—per mole of protein. Three different binding sites in rhodopsin were considered based on computational chemistry studies, and a quantitative analysis of the XAS signal was performed by fitting the experimental data to their simulated XAS spectra. Our results demonstrate that Zn2+ is intrinsically bound to rhodopsin and are compatible with the existence of an octahedral coordination involving six oxygen atoms in the first shell (average Zn‐O distance of 2.08 Å), and with a second coordination shell containing one or two phosphorus or sulfur atoms at an average distance of 2.81 Å.
Light‐sensitive Intelligent Drug Delivery Systems†
Authors: Alvarez‐Lorenzo Carmen , Bromberg Lev , Concheiro Angel 
Published: February 2009

AbstractDrug delivery systems (DDS) capable of releasing an active molecule at the appropriate site and at a rate that adjusts in response to the progression of the disease or to certain functions/biorhythms of the organism are particularly appealing. Biocompatible materials sensitive to certain physiological variables or external physicochemical stimuli (intelligent materials) can be used for achieving this aim. Light‐responsiveness is receiving increasing attention owing to the possibility of developing materials sensitive to innocuous electromagnetic radiation (mainly in the UV, visible and near‐infrared range), which can be applied on demand at well delimited sites of the body. Some light‐responsive DDS are of a single use (i.e. the light triggers an irreversible structural change that provokes the delivery of the entire dose) while others able to undergo reversible structural changes when cycles of light/dark are applied, behave as multi‐switchable carriers (releasing the drug in a pulsatile manner). In this review, the mechanisms used to develop polymeric micelles, gels, liposomes and nanocomposites with light‐sensitiveness are analyzed. Examples of the capability of some polymeric, lipidic and inorganic structures to regulate the release of small solutes and biomacromolecules are presented and the potential of light‐sensitive carriers as functional components of intelligent DDS is discussed.
Requirement for Metalloproteinase‐dependent ERK and AKT Activation in UVB‐induced G1‐S Cell Cycle Progression of Human Keratinocytes
Authors: Han Weinong , He Yu‐Ying 
Published: February 2009

AbstractUVB (280–315 nm) in natural sunlight represents a major environmental challenge to the skin and is clearly associated with human skin cancer. Here we demonstrate that low doses of UVB induce keratinocyte proliferation and cell cycle progression of human HaCaT keratinocytes. Different from UVA, UVB irradiation induced extracellular signal‐regulated kinase (ERK) and AKT activation and their activation are both required for UVB‐induced cell cycle progression. Activation of epidermal growth factor receptor (EGFR) was observed after UVB exposure and is upstream of ERK/AKT/cyclin D1 pathway activation and cell cycle progression following UVB radiation. Furthermore, metalloproteinase (MP) inhibitor GM6001 blocked UVB‐induced ERK and AKT activation, cell cycle progression, and decreased the EGFR phosphorylation, demonstrating that MPs mediate the EGFR/ERK/AKT/cyclin D1 pathways and cell cycle progression induced by UVB radiation. In addition, ERK or AKT activation is essential for EGFR activation because ERK or AKT inhibitor blocks EGFR activation following UVB radiation, indicating that EGFR/AKT/ERK pathways form a regulatory loop and converge into cell cycle progression following UVB radiation. Identification of these signaling pathways in UVB‐induced cell cycle progression of quiescent keratinocytes as a process mimicking tumor promotion in vivo will facilitate the development of efficient and safe chemopreventive and therapeutic strategies for skin cancer.
Chlorin–Bacteriochlorin Energy‐transfer Dyads as Prototypes for Near‐infrared Molecular Imaging Probes: Controlling Charge‐transfer and Fluorescence Properties in Polar Media
Authors: Kee Hooi Ling , Diers James R. , Ptaszek Marcin , Muthiah Chinnasamy , Fan Dazhong , Lindsey Jonathan S. , Bocian David F. , Holten Dewey 
Published: February 2009

AbstractThe photophysical properties of two energy‐transfer dyads that are potential candidates for near‐infrared (NIR) imaging probes are investigated as a function of solvent polarity. The dyads (FbC‐FbB and ZnC‐FbB) contain either a free base (Fb) or zinc (Zn) chlorin (C) as the energy donor and a free base bacteriochlorin (B) as the energy acceptor. The dyads were studied in toluene, chlorobenzene, 1,2‐dichlorobenzene, acetone, acetonitrile and dimethylsulfoxide (DMSO). In both dyads, energy transfer from the chlorin to bacteriochlorin occurs with a rate constant of ∼(5–10 ps)−1 and a yield of >99% in nonpolar and polar media. In toluene, the fluorescence yields (Φf = 0.19) and singlet excited‐state lifetimes (τ∼5.5 ns) are comparable to those of the benchmark bacteriochlorin. The fluorescence yield and excited‐state lifetime decrease as the solvent polarity increases, with quenching by intramolecular electron (or hole) transfer being greater for FbC‐FbB than for ZnC‐FbB in a given solvent. For example, the Φf and τ values for FbC‐FbB in acetone are 0.055 and 1.5 ns and in DMSO are 0.019 and 0.28 ns, whereas those for ZnC‐FbB in acetone are 0.12 and 4.5 ns and in DMSO are 0.072 and 2.4 ns. The difference in fluorescence properties of the two dyads in a given polar solvent is due to the relative energies of the lowest energy charge‐transfer states, as assessed by ground‐state redox potentials and supported by molecular‐orbital energies derived from density functional theory calculations. Controlling the extent of excited‐state quenching in polar media will allow the favorable photophysical properties of the chlorin–bacteriochlorin dyads to be exploited in vivo. These properties include very large Stokes shifts (85 nm for FbC‐FbB, 110 nm for ZnC‐FbB) between the red‐region absorption of the chlorin and the NIR fluorescence of the bacteriochlorin (λf = 760 nm), long bacteriochlorin excited‐state lifetime (∼5.5 ns), and narrow (≤20 nm) absorption and fluorescence bands. The latter will facilitate selective excitation/detection and multiprobe applications using both intensity‐ and lifetime‐imaging techniques.
Pre‐transfusion testing
Authors: White J. 
Published: February 2009

The first step in successful pre‐transfusion testing is receipt of timely requests for blood with adequate clinical details and correctly labelled samples, to enable the laboratory to provide compatible blood components, that meet any special requirements for the patient, e.g. irradiated, phenotyped. Establishing compatibility and suitability of blood for a patient is a complex process including: sample acceptance; checking historical records; testing for ABO/D; antibody screening and identification; serological or electronic crossmatching; selecting appropriate blood components; labelling and issue.The specifications for routine serological testing and final method of establishing compatibility will depend on the resources available, and on national policy and guidelines. Variability in resources includes: access to historical records; standard of reagents available for serological testing; level of IT; use of automation; and availability of staff with specialist transfusion training. Different testing protocols may be required for specific groups of patients such as neonates, transfusion dependent patients and transplant recipients.Quality assurance is essential throughout the process. The risk of error in pre‐transfusion testing varies considerably depending on the combination of tests and procedures selected together, and a risk assessment of the overall process is advisable. A higher proportion of errors occur ‘out of hours’, where staff are working under pressure, and may be using non‐routine techniques. Safety can be improved by managing emergency and ‘out of hours’ requests, and applying ‘maximum blood ordering schedules’ to reduce unnecessary crossmatching. Well designed procedures and policies can do as much to improve safety as accurate and sensitive techniques.
Hepatitis C infection: recent insights relevant to transfusion safety
Authors: Busch M. P. , Kleinman S. H. 
Published: February 2009

Hepatitis C virus (HCV) infects over 100 million persons worldwide, and is hence one of the most prevalent and clinically significant blood‐borne pathogens. The introduction of HCV antibody screening in the early 1990s led to detection of large numbers of infected donors and dramatic increases in blood safety. The seroprevalence of HCV in blood donors varies, ranging from rates as low as 0·01% in South Africa to ~0·5% in most developed countries, to > 5% in focal endemic areas such as Egypt. Studies of HCV in infected donors and recipients were instrumental in the discovery of HCV, and have yielded ongoing insights into HCV epidemiology, natural history and pathogenesis. Recent examples include detailed characterization of the dynamics of acute HCV infection based on studies of plasma donor panels, and important contributions to understanding viral and host factors influencing HCV transmission and disease outcome based on linked donor‐recipient cohort studies. The addition of nucleic acid testing (NAT) for HCV RNA to routine HCV antibody screening of donors in 1999 further reduced the risk of transfusion‐transmitted HCV. Mini‐pool (MP)‐NAT screening has led to detection of well over 500 donors in the viraemic, preseroconversion phase of primary HCV infection, as well as to discrimination of seropositive donors into those with resolved and chronic infections. Studies of donors with acute, chronic/persistent and resolved HCV infections have further contributed to our understanding of viral and host genetic and immunological determinants of spontaneous clearance of HCV and short‐ and long‐term disease outcomes. This review will highlight these past scientific contributions, and present the results of a recent survey of the yield of HCV MP‐NAT screening and estimated residual risks of MP‐NAT screened transfusions in different regions of the world. Finally, the review will discuss available evidence for the infectivity of very low‐level viraemia that may be missed by MP‐NAT, information that is pivotal to modelling the residual risk of MP‐NAT screened blood transfusions, and which will guide further strategies to reduce risk by further enhancing screening or implementation of pathogen‐inactivation technologies.
The impact of training in transfusion medicine
Authors: Damanhouri G. A. 
Published: February 2009

Background  Basic training skills and program for all health care providers working in the blood transfusion services is important and essential. All blood transfusion staff should have active participation in a training program that includes teaching all national and international regulations related to blood transfusion administration and guidelines of safe blood and blood products. The blood bank staff (physicians, medical technologists and nurses) should pass proper assessment procedures in order to work in this vita health related services. All staff working in blood transfusion services should receive a proper education and learning skills in this field of medicine. Awareness of blood safety and Good Manufacturing Practice (GMP) in blood transfusion should be greatly increased among them.Methods and Results  Sustainable national and international education and training in blood transfusion services are needed and should be considered as a priority. Methods of teaching and training may include courses or workshops consist of a series of lectures, practical sessions, problem based learning and computer based distance learning programs. A proper training and continuous medical education in blood transfusion services have played an important role in minimizing the risk of transfusion related complications in many countries.Conclusions  Creating an effective learning and training environment is a real challenge for most developing countries. Transfusion medicine is a branch of medicine which has a great link with almost all medical and surgical specialties. Blood transfusion safety plays an important and significant role in the patient's management. Proper qualified training personnel are the key of delivering safe blood components and the Good Manufacturing Practice (GMP) in blood transfusion services.
Generation and characterization of mesenchymal stromal cells for clinical application
Authors: Sensebé L. 
Published: February 2009

Mesenchymal Stem Cells/Multipotent Marrow Stromal Cells (MSC) are multipotent adult stem cells harboring a wide range of differentiation capacities as well as non‐HLA restricted immunosuppressive properties, leading to an increase in their uses for immunomodulation and regenerative medicine. MSC are generally cultivated from bone marrow (BM). Alternative sources (e.g. adipose tissue or umbilical cord) are rapidly developing. Considering the starting material used, the differentiation potential may be different, in example adipose tissue derived MSC exhibit a greater potential for endothelium repair. Whatever the sources of MSC, a first step of adherence to plastic is required. When seeding, the cell density is of major importance acting on growth speed, cell amplification, and differentiation potential. Considering medium used, until now serum free media are not available to cultivate MSC for clinical application. Standard process with FCS without any growth factor supplementation is effective but time consuming, sometime failing, and not totally secure. Although processes using recombinant growth factors (e.g. FGF2) or platelet lysate have demonstrated their interest, definitive standards to produce clinical‐grade MSC are still lacking. To reach GMP standards, two major steps have to be done. First, MSC cultures need to be done in closed system; this step is not easy to perform. Second, the controls of produced batches have to ensure efficacy and safety. Now, the controls are principally based on FACS analysis and the expected CD73posCD105posCD90posCD45neg MSC phenotype is easily obtained. But the major problem remains the lack of fully validated controls of the final cell product efficacy and safety. Considering the genetic stability of MSC during culture processes, whatever the culture method, aneuploidy could occur during clinical‐grade production of BM‐MSC but does not lead to cell transformation. But these results should lead to develop more accurate and powerful controls of all MSC in cultures.
Questions de conservation : particularités et nouvelles technologies
Authors: Memet Jean‐Bernard 
Published: February 2009

RésuméAvec le développement de l’archéologie sous‐marine et la mise au jour croissante de vestiges sous l’eau, la conservation et la restauration du patrimoine culturel subaquatique se sont avérées être des étapes essentielles pour la protection et la mise en valeur de cet héritage de l’humanité. C’est pourquoi archéologues et restaurateurs doivent travailler de concert pour étudier et préserver des découvertes souvent fragiles, surtout lorsqu’elles sont extraites de l’eau ou tout simplement sorties de leur contexte. Chacun doit connaître le métier de l’autre. L’archéologue doit avoir une bonne compréhension des interactions entre le milieu aquatique et les matériaux et être prêt à effectuer les premiers soins. Le conservateur, quant à lui, doit être au fait non seulement des matériaux et de leur mode de dégradation ainsi que des techniques de restauration et de conservation, mais aussi du milieu environnant en devenant lui‐même plongeur.
La Convention de l’UNESCO sur la protection du patrimoine culturel subaquatique de 2001 : avantages et défis
Authors: Koschtial Ulrike 
Published: February 2009

RésuméL’article explique la Convention de l’UNESCO sur la protection du patrimoine culturel subaquatique de 2001. Élaborée pour lutter contre le pillage et la destruction dont ce patrimoine est victime de façon croissante, la Convention engage les États souverains qui en sont devenus parties. Sans modifier leurs droits souverains ni réglementer la propriété des épaves ou des vestiges submergés, elle tente d’instaurer une protection globale du patrimoine culturel subaquatique, où qu’il se trouve, et d’harmoniser ladite protection avec celle du patrimoine terrestre. La Convention entrant en vigueur le 2 janvier 2009, le moment est idéal pour en expliquer les tenants et aboutissants et son importance pour le développement de l’archéologie subaquatique et des musées liés à cette activité.
Des itinéraires archéologiques au fond des mers
Authors: Alves Francisco J. S. 
Published: February 2009

RésuméCet article est un panorama international de la muséalisation du patrimoine culturel immergé et un coup de projecteur sur les expériences portugaises de création d’itinéraires archéologiques subaquatiques, à la lumière des concepts de conservation in situ et d’accès durable du public consacrés par la Convention de l’UNESCO de 2001 sur la protection du patrimoine culturel subaquatique.
L’Exploration archéologique subaquatique des cénotes mayas
Authors: López Luis Alberto Martos 
Published: February 2009

RésuméLes cénotes sont des formations géologiques naturelles le plus souvent reliées à des galeries souterraines et à des nappes phréatiques. Ces puits naturels constituent des systèmes hydrauliques complexes et dynamiques qui ont, pendant longtemps, connu des liens étroits avec les sociétés environnantes. Ces « capsules à remonter le temps » renferment des informations pertinentes sur les aspects symboliques et religieux de la culture maya, aussi bien que sur l’histoire géologique de la péninsule du Yucatán. Les archéologues, les géologues et les biologistes travaillent de concert pour étudier ces sites uniques en utilisant les techniques de plongée spéléologique. Cependant, les cénotes sont devenus une attraction touristique et un lieu de rencontres sportives et, de ce fait, la chasse au trésor représente une réelle menace pour leur intégrité. Un programme de gestion durable de ce patrimoine culturel exceptionnel devrait permettre de favoriser tout à la fois son accès au public et sa préservation.
Subaqueous eruption and shallow-water reworking of a small-volume Surtseyan edifice at Kakanui, New Zealand
Authors: Corcoran P. L. , Moore L. N. 
Published: February 2009

Kakanui volcaniclastic deposits on the South Island of New Zealand are the remnants of two late Eocene to early Oligocene Surtseyan-type cones. Eruptive-dominated material of the (i) stratified tuff and lapilli tuff, and (ii) lapilli tuff breccia lithofacies and post-eruptive debris of the (iii) shell-rich tuff and lapilli tuff, and (iv) chaotic and cross-bedded tuff and lapilli tuff lithofacies compose the deposits. The 9–250 m thick stratified tuff and lapilli tuff contains grain-flow deposits originating from low-volume tephra jets and local thinning and fining upward sequences that formed from density currents during sustained uprush. The lapilli tuff breccia, up to 4.5 m thick, contains inward-dipping beds deposited via debris flows along inner-cone walls. Burrows and articulated shells in the 2–4 m thick shell-rich tuff and lapilli tuff indicate volcanic quiescence and low sedimentation rates, whereas shell fragments upsection signal increased wave and current activity. Burrows, pyrite concretions, and mudstone in the lower part of the 26 m thick chaotic tuff and lapilli tuff indicate suspension deposition and cessation in pyroclastic volcanism. High-angle trough cross-beds and limestone rip-up fragments upsection are consistent with wave-induced current reworking. The depositional model involves a Surtseyan-type eruption on a continental shelf, followed by colonization of organisms on the tops of planed-off cones. The Kakanui deposits comprise a cluster of cones constituting part of a late Eocene – early Oligocene monogenetic volcanic field. The Kakanui succession provides an opportunity to study deposits that form from explosive subaqueous pyroclastic eruptions and wave-dominated deposition and erosion.