bluuebunny/crossref_metadata_2025 huggingface dataset:
Physical and Temporal Scaling Considerations in a Robot Model of Cricket Calling Song Preference
Authors: Lund Henrik Hautop , Webb Barbara , Hallam John
Published: July 2002

Behavioral experiments with crickets show that female crickets respond to male calling songs with syllable rates within a certain bandwidth only. We have made a robot model in which we implement a simple neural controller that is less complex than the controllers traditionally hypothesized for cricket phonotaxis and syllable rate preference. The simple controller, which had been successfully used with a slowed and simplified signal, is here demonstrated to function, using songs with identical parameters to those found in real male cricket song, using an analog electronic model of the peripheral auditory morphology of the female cricket as the sensor. We put the robot under the same experimental conditions as the female crickets, and it responds with phonotaxis to calling songs of real male Gryllus bimaculatus. Further, the robot only responds to songs with syllable rates within a bandwidth similar to the bandwidth found for crickets. By making polar plots of the heading direction of the robot, we obtain behavioral data that can be used in statistical analyses. These analyses show that there are statistically significant differences between the behavioral responses to calling songs with syllable rates within the bandwidth and calling songs with syllable rates outside the bandwidth. This gives the verification that the simple neural control mechanism (together with morphological auditory matched filtering) can account for the syllable rate preference found in female crickets. With our robot system, we can now systematically explore the mechanisms controlling recognition and choice behavior in the female cricket by experimental replication.
Stakeholders Influence and Internal Championing of Product Stewardship in the Italian Food Packaging Industry
Authors: Braglia Marcello , Petroni Alberto
Published: July 2002

Environmental management is becoming a top issue on managers' agendas in several industries. The adoption and implementation of a sound “green” strategy involves following product stewardship practices. Product stewardship is the idea that manufacturers, rather than consumers, governments, or waste companies, ought to take responsibility for the recycling and disposal of their products at the end of their life cycle. This article is aimed at investigating the relationships between the adoption of product stewardship practices and the involvement of different actors in the decision‐making process. By means of discriminant analysis, 120 firms have been classified into two different environmental profiles. Results indicate that firms that are more committed to product stewardship differ from less‐committed firms in the influence exerted by different stakeholders and in the supportive role played by the management at different hierarchical and functional levels. In general, it appears that top management involvement in the decision‐making process is a critical condition for the successful championship of product stewardship. In addition, the effective implementation of product stewardship along the product life‐cycle stages is correlated to a strong commitment on the part of chief technical officers and development engineers rather than of manufacturing or marketing managers.
Materials Flow Analysis of the Italian Economy
Authors: de Marco Ottilia , Lagioia Giovanni , Mazzacane Elsa Pizzoli
Published: July 2002

This article analyzes the mass of the materials that flowed through the Italian economy during 1994 and compares the results with a similar analysis of Germany, Japan, the Netherlands, and the United States published by a collaboration headed by the World Resources Institute. In order to perform this comparison, we have evaluated the mass of the materials produced within the country and the mass of the imported materials and commodities. For the domestic production, imports and exports, we have also evaluated the mass of the materials that accompany—as “hidden flows”—each physical flow.

Our analysis indicates that, in 1994, Italy experienced total material requirements (TMR) of 1,609 million metric tons (Mt), of which 727 Mt was used as direct material input (DMI). A comparison with other developed countries shows that the TMR and DMI flows, measured in mass per person and in mass per GDP unit, are, in Italy, lower than the corresponding figures evaluated for the United States, Germany, and the Netherlands. An interpretation of these results is presented. The analysis may give information useful for environmental considerations, although the limits of such an approach are made clear.
TEMPORAL PATTERNS OF PARENTAL RESOURCE DISTRIBUTION IN THE RED-NECKED GREBE: EQUALIZING THE SHARE OF THE SURVIVORS
Authors: Kloskowski Janusz
Published: July 2002

Food distribution within brood and parental aggression to chicks were studied in the asynchronously hatching red-necked grebe Podiceps grisegena throughout the whole period of parental care. When carrying young - during the first two weeks after hatching - parents did not interfere in sibling competition for food. The proportions of food received by each brood member reflected the dominance hierarchy. After this period, parents showed aggression to offspring, especially to the older chicks and the within-brood hierarchy of received food was gradually reversed. Junior chicks were also longer cared for than their older sibling. Male and female parents did not differ in the food apportionment among differentrank chicks. It is suggested that red-necked grebe parents change the within-brood investment allocation over time. In the first weeks after hatching, they allow biased food distribution and in consequence even brood reduction. Later, they intervene in resource allocation and attempt to equalize the post-fledging survival of all chicks. Parental aggression appears to be a means both for counteracting the competitive advantage of older sibs and for forcing the chicks to independence.
SETT USE IN EUROPEAN BADGERS MELES MELES
Authors: Roper  , Ostler  , Schmid  , Christian
Published: July 2002

The European badger Meles meles constructs burrows of two basic types: 'main setts' and 'outliers'. We examined daytime burrow use year-round in 19 radio-collared badgers belonging to six different social groups, in order to test the hypotheses relating use of multiple sleeping sites to ectoparasite avoidance and social status. Ten animals rarely or never slept away from the main sett, while the remaining nine animals spent 20-73% of their days in outliers, mainly in summer. Outlier use was not related to sex or body condition, but animals that used outliers tended to be younger and had larger numbers of fleas than those that remained in the main sett year-round. Within the main sett, all the members of a social group had overlapping ranges: i.e. the sett was not divided into separate 'territories'. Group ranges were smallest in winter and largest in summer/autumn. Nest chambers were usually shared between at least two members of a social group on any one day, but males slept alone more often than did females. Individuals tended to cluster together in the same nest chamber more in winter than at other times of year, presumably to gain thermoregulatory advantage from huddling. We conclude that the pattern of burrow use in badgers is complex. Use of space within the main sett and tendency to disperse to outliers in the summer are in part affected by ectoparasite infestation, while use of space within the main sett is also influenced by variables such as sex and age that may reflect social status.
DESCRIPTION OF A NEW SPECIES OF SOMANNIATHELPHUSA (DECAPODA, BRACHYURA, PARATHELPHUSIDAE) FROM VIETNAM
Authors: Quynh Nguyen Xuan , Yeo Darren
Published: July 2002

A new species of ricefield crab belonging to the genus Somanniathelphusa is described from Hanoi, Vietnam. It is the second Somanniathelphusa species to be described from Hanoi in recent years, differing from its congeners mainly by the form of its G1. Une nouvelle espece de crabe de riziere appartenant au genre Somanniathelphusa est decrite de Hanoi, Vietnam. C'est la seconde espece de Somanniathelphusa a etre decrite de Hanoi au cours des dernieres annees. Elle differe de ses congeneres principalement par la forme de la premiere paire de pleopodes du male.
Mineralogy of the <2 μm fraction of three mixed-layer clays from southern and central Tunisia
Authors: Ben Rhaiem H. , Tessier D. , Ben Haj Amara A.
Published: July 2002

Three clay minerals from southern and central Tunisia were characterized. Both XRD quantitative analysis and a chemical method were used to determine the mineralogical and physico-chemical characteristics of the <2 μm clay fractions. The XRD, CEC and specific surface measurement analyses showed that the dominant phase in all samples is illite-smectite with kaolinite and traces of quartz also present. From quantitative XRD, the abundances of the minerals identified are consistent with the measured CEC, specific surface area and TG/DTA properties. Analysis by XRD also showed that the illite-smectite phases are composed of thin stacks (two to a maximum of ten layers per stack) of random illite-smectite and ordered (R1) illite-smectite. There is also some discrete illite.
Distribution and origin of clay minerals in the Lower Cretaceous of the Alava Block (Basque-Cantabrian Basin, Spain)
Authors: Sangüesa F. J. , Arostegui J. , Suarez-Ruiz I.
Published: July 2002

Lower Cretaceous clay minerals suites of the Alava Block, analysed by XRD, are dominated either by illite or kaolinite. These assemblages are mainly inherited in origin, although textural evidence (SEM) indicates some diagenetic clay. Precipitation of blocky kaolinite took place in sandstones from the southern domain of the Block, characterized by low sedimentation and subsidence rates and by low vitrinite reflectance values (%Rr <0.8). In the northern domain, where sedimentation and subsidence rates were high (%Rr >3.3), illitization of kaolinite and smectitic clays and precipitation of authigenic chlorite occurred. Some chemical aspects of these reactions are discussed.
Paragenesis of Cu-Fe ores from Ocna de Fier-Dognecea (Romania), typifying fluid plume mineralization in a proximal skarn setting
Authors: Cook N. J. , Ciobanu C. L.
Published: July 2002

Trace mineral assemblages in the bornite- and chalcopyrite-rich Cu-Fe zone of the Ocna de Fier-Dognecea skarn deposits, Banat, SW Romania provide additional constraints on the genesis of this classic zoned skarn system. Observed assemblages substantiate a model, in which the Cu-Fe zone forms the proximal fluid-plume root of the system. Observed trace mineral assemblages in the magnesian forsterite-bearing skarns crystallized at ~650°C in a volatile-rich environment, evidenced by widespread phlogopite, ludwigite, valleriite and apatite. The entire assemblage thus belongs to the initial stage of skarn formation. Prolonged cooling led to sequential exsolution of trace mineral phases from bornite and chalcopyrite during the retrograde stage, although still at temperatures in excess of 500°C. Bornite is typified by the abundance of exsolved phases along cleavage planes and along crystal margins, notably chalcopyrite and pyrrhotite, but also cobalt pentlandite, carrollite, wittichenite, galena, mawsonite, silver and electrum. Chalcopyrite hosts cobalt pentlandite, carrollite, wittichenite, galena and a sequence of Se- and Te-bearing minerals (kawazulite, bohdanowiczite, hessite, volynskite), along, although not restricted to, grain margins. The assemblage bornite-chalcopyrite-magnetite, with the trace phases, cobalt pentlandite, carrollite, wittichenite and various Se- and Te-bearing minerals represents a characteristic assemblage common to a disparate range of deposits formed at temperatures in excess of 500°C in the presence of volatiles and typified by relatively low fS2 fluids.
Nb-rich brookite from Gross Brukkaros, Namibia: substitution mechanisms and Fe2+/Fe3+ ratios
Authors: Werner M. , Cook N. J.
Published: July 2002

Idioblastic, mm-scale brookite is reported from SiO2-Ba-Fe-rich metasomatic rocks from the carbonatitic Gross Brukkaros Volcanic Field, Southern Namibia. Electron probe microanalysis shows significant concentrations of Nb (12–17 wt.% Nb2O5), coupled with Fe, substituting for Ti in the structure. Calculation of the analytical data indicates evolving Fe2+/(Fe2++Fe3+) ratios during crystallization and two distinct substitution mechanisms in operation: 2Ti4+ ⇋ Nb5+ + Fe3+ and 3Ti4+ ⇋ 2Nb5+ + Fe2+. The compositional patterns observed are explained in terms of initial growth in an environment which evolved from oxidizing to reducing. The outermost 10 µm rims of the crystals are characterized by oxidizing conditions, resulting from a subsequent metasomatic overprint.
Cation distribution in natural Zn-aluminate spinels
Authors: Lucchesi S. , Della Giusta A. , Russo U.
Published: July 2002

The intracrystalline cation distributions in fourteen natural Zn-aluminate spinels were determined by means of X-ray single-crystal structural refinement, supported for some samples by Mössbauer spectroscopy.

Zinc substitutes for Mg and subordinately Fe2+ and its relevant changes in content, from 0.10 to 0.96 atoms per formula unit (apfu), are not related to variations of cell parameter. The latter is determined mainly by the substitution Fe3+ ⇌ Al. In agreement with data from synthetic samples, a small but definite amount of Zn (up to 0.06 apfu) is located in the octahedral M site. Fe2+, when present, shows a preference for tetrahedral coordination.

An improved value of the tetrahedral Zn(T)-O distance (1.960 Å) was obtained, integrating the set of interatomic distances used for the determination of cation distribution in spinels.
Defect structure and luminescence behaviour of agate — results of electron paramagnetic resonance (EPR) and cathodoluminescence (CL) studies
Authors: Götze J. , Plötze M. , Fuchs H. , Habermann D.
Published: July 2002

Samples of agate and quartz incrustations from different parent volcanic rocks of certain world-wide localities were investigated by EPR, CL and trace element analysis. In all agate samples the following paramagnetic centres were detected:, E′1, [AlO4]0 [FeO4/M+]0 and [GeO4/M+]0. Centres of the type [TiO4/Li+]0 and [TiO4/H+]0, which were detected in quartz of the parent volcanics, are absent in agate. Generally, the abundance of centres (silicon vacancy) and E′1 centres (oxygen vacancy) in agate is remarkably higher than in quartz. The high defect density in agates points to rapid growth of silica from a strongly supersaturated solution probably with a noncrystalline precursor.

CL microscopy reveals internal structures and zoning in agates and quartz incrustations which clearly differ from those discernible by conventional polarizing microscopy. The CL spectra of agates differ from those of quartz from crystalline rocks. At least three broad emission bands were detected in the CL spectra: a blue band of low intensity, a yellow band at about 580 nm, and an intense red band at 650 nm. The CL emission at 650 nm shows some relations to the hydroxyl or alkali content and the abundance of centres and E′1 centres. The emission intensity increases during electron bombardement due to the conversion of different precursors (e.g. ≡Si-O-H, ≡Si-O-Na groups) into hole centres. Another conspicuous feature in the CL spectra of agates is the existence of a yellow emission band centred at around 580 nm. The predominance of the yellow CL emission band and the high concentration of E′1 centres are typical for agates of acidic volcanics and are indicative of a close relationship between the two.
Carbon isotope ratios and nitrogen abundances in relation to
cathodoluminescence characteristics for some diamonds from the Kaapvaal Province,
S. Africa
Authors: Harte B. , Fitzsimons I. C. W. , Harris J. W. , Otter M. L.
Published: July 2002

Secondary ion mass spectrometry (SIMS) techniques have been used to study the
variation of C isotope ratio and N abundance within selected diamonds in relation
to their crystal growth zones. The growth zones are seen in cathodoluminescence
(CL), and include both octahedral and cuboid zones within typical diamonds of
external octahedral morphology. Compositions were determined by use of a primary
133Cs+ ion beam and measurement of
12C−, 13C, and
12C14N−
secondary ions at high mass resolution on a Cameca ims-4f ion microprobe at
Edinburgh University.

In each of the diamonds, different growth zones have marked differences in N
abundance, which are as great as 0–1400 ppm within one diamond. Changes of several
hundred ppm N are common across both octahedral and cuboid growth zones, and
appear sharp and abrupt at the boundaries of the growth zones. In general for the
common blue CL, luminescence increases with N abundance. The changes in N
abundance across fine scale (∼100 µm) growth zones show that the total N contents
determined by IR spectroscopy may show great variations of abundance. In contrast,
within detection limits, δ13C appears constant across many
growth zone boundaries. Thus the factors controlling uptake of N from the
fluid/melt reservoir in which natural diamonds grow often do not influence
δ13C. No evidence of progressive variation or
fractionation of C isotopes during growth was found.

Some original variation in C isotope composition may have been eliminated by
diffusion of C atoms subsequent to growth, because of the storage of natural
diamonds over millions of years in the Earth's mantle at temperatures of
950–1250°C. Such atomic mobility does not homogenize N distribution because of the
proven tendency of N to form aggregates of atoms. A survey of experimental
estimates of single atom (C) diffusion parameters, suggests that diffusion
distances of ∼100 µm are likely at high temperatures (∼1100°C) over long time
periods (∼1.0 Ga). Therefore, with refinement of the diffusion parameters and
measurements, the extent of C isotope homogenization in natural diamonds, as well
as N aggregation state, might provide quantitative evidence of their
time-temperature history under mantle conditions.
Phosphoinositide 3-kinase modulation of β3-integrin represents an endogenous “braking” mechanism during neutrophil transmatrix migration
Authors: Bruyninckx Walter J. , Comerford Katrina M. , Lawrence Donald W. , Colgan Sean P.
Published: July 2002

During episodes of inflammation, neutrophils (polymorphonuclear leukocytes [PMNs]) encounter subendothelial matrix substrates that may require additional signaling pathways as directives for movement through the extracellular space. Using an in vitro endothelial and epithelial model, inhibitors of phosphoinositide 3-kinase (PI3K) were observed to promote chemoattractant-stimulated migration by as much as 8 ± 0.3-fold. Subsequent studies indicated that PMNs respond in a similar manner to RGD-containing matrix substrates and that PMN-matrix interactions are potently inhibited by antibodies directed against β3- but not β1-integrin antibodies, and that PI3K inhibitors block β3-integrin dependence. Biochemical analysis of intracellular β3-integrin uncoupling by PI3K inhibitors revealed diminished β3-integrin tyrosine phosphorylation and decreased association with p72syk. Similarly, the p72sykinhibitor piceatannol promoted PMN transmatrix migration, whereas HIV-tat peptide-facilitated loading of peptides corresponding to the β3-integrin cytoplasmic tail identified the functional tyrosine residues for this activity. These data indicate that PI3K-regulated β3-integrin represents a natural “braking” mechanism for PMNs during transit through the extracellular matrix.
Modifications in the CD36 binding domain of the Plasmodium falciparum variant antigen are responsible for the inability of chondroitin sulfate A adherent parasites to bind CD36
Authors: Gamain Benoit , Smith Joseph D. , Miller Louis H. , Baruch Dror I.
Published: July 2002

Adhesion of mature Plasmodium falciparum parasitized erythrocytes to microvascular endothelial cells or to placenta contributes directly to the virulence and severe pathology of P falciparum malaria. Whereas CD36 is the major endothelial receptor for microvasculature sequestration, infected erythrocytes adhering in the placenta bind chondroitin sulfate A (CSA) but not CD36. Binding to both receptors is mediated by different members of the large and diverse protein family P falciparum erythrocyte membrane protein-1 (PfEMP-1) and involves different regions of the molecule. The PfEMP-1–binding domain for CD36 resides in the cysteine-rich interdomain region 1 (CIDR-1). To explore why CSA-binding parasites do not bind CD36, CIDR-1 domains from CD36- or CSA-binding parasites were expressed in mammalian cells and tested for adhesion. Although CIDR-1 domains from CD36-adherent strains strongly bound CD36, those from CSA-adherent parasites did not. The CIDR-1 domain has also been reported to bind CSA. However, none of the CIDR-1 domains tested bound CSA. Chimeric proteins between CIDR-1 domains that bind or do not bind CD36 and mutagenesis experiments revealed that modifications in the minimal CD36-binding region (M2 region) are responsible for the inability of CSA-selected parasites to bind CD36. One of these modifications, mapped to a 3–amino acid substitution in the M2 region, ablated binding in one variant and largely reduced binding of another. These findings provide a molecular explanation for the inability of placental sequestered parasites to bind CD36 and provide additional insight into critical residues for the CIDR-1/CD36 interaction.
Ordered recombination of immunoglobulin light chain genes occurs at the IGK locus but seems less strict at theIGL locus
Authors: van der Burg Mirjam , Tümkaya Talip , Boerma Marjan , de Bruin-Versteeg Sandra , Langerak Anton W. , van Dongen Jacques J. M.
Published: July 2002

Regulation of allelic and isotypic exclusion of human immunoglobulin (Ig) light-chain genes was studied in 113 chronic B-cell leukemias as a “single-cell” model that allowed complete analysis of each light chain allele. Our data show that monospecific Ig light chain expression is in about 90% of cases determined by ordered recombination: Igκ gene (IGK) rearrangements, followed byIGK deletions and Igλ gene (IGL) rearrangements, resulting in the presence of only one functional Ig light chain rearrangement. In about 10% (10 cases), 2 functional Ig light chain rearrangements (IGK/IGL or IGL/IGL, but not IGK/IGK) were identified. This might be explained by the fact that regulation of the ordered recombination process is not fully strict, particularly when the IGL locus is involved. Unfavorable somatic mutations followed by receptor editing might have contributed to this finding. Eight of these 10 cases indeed contained somatic mutations. In cases with 2 functional Ig light chain rearrangements, both alleles were transcribed, but monospecific Ig expression was still maintained. This suggests that in these cases allelelic exclusion is not regulated at the messenger RNA level but either at the level of translation or protein stability or via preferential pairing of Ig light and Ig heavy chains. Nevertheless, ordered rearrangement processes are the main determinant for monospecific Ig light chain expression.
Coexpression of band 3 mutants and Rh polypeptides: differential effects of band 3 on the expression of the Rh complex containing D polypeptide and the Rh complex containing CcEe polypeptide
Authors: Beckmann Roland , Smythe Jonathan S. , Anstee David J. , Tanner Michael J. A.
Published: July 2002

K562 cells were stably transfected with cDNAs encoding the band 3 found in Southeast Asian ovalocytosis (B3SAO, deletion of residues 400-408), band 3 with a transport-inactivating E681Q point mutation (B3EQ), or normal band 3 (B3). Flow cytometric analysis and quantitative immunoblotting revealed that B3SAO expressed alone was translocated to the plasma membrane, at levels similar to B3 or B3EQ. Nine monoclonal antibodies that reacted with extracellular loops of B3 also reacted with B3SAO, although the affinity of most antibodies for the mutant protein was reduced. Both known Wrb epitopes were expressed on K562/B3SAO cells, demonstrating that B3SAO interacts with glycophorin A. The growth rates of K562 clones expressing equivalent amounts of B3 and B3EQ were the same, suggesting that the potentially toxic transport function of band 3 may be regulated in K562 cells. The band 3–mediated enhancement of Rh antigen reactivity and the depression of Rh epitopes on SAO erythrocytes were investigated by comparing the coexpression of B3, B3SAO, or B3EQ in K562 clones expressing exogenous RhcE or RhD polypeptides. The results are consistent with an interaction between band 3 and the Rh polypeptide–Rh glycoprotein (RhAG) complex, which may enhance translocation of the complex or affect its conformation in the plasma membrane. The data suggest that the interaction between band 3 and the RhD–RhAG complex is weaker than it is between band 3 and the RhCcEe–RhAG complex.
Proliferation of primitive myeloid progenitors can be reversibly induced by HOXA10
Authors: Björnsson Jon Mar , Andersson Elisabet , Lundström Patrik , Larsson Nina , Xu Xiufeng , Repetowska Ewa , Humphries R. Keith , Karlsson Stefan
Published: July 2002

Recent studies show that several Hox transcription factors are important for regulation of proliferation and differentiation in hematopoiesis. Among these is H0XA10, which is selectively expressed at high levels in the most primitive subpopulation of human CD34+ bone marrow cells. When overexpressed, H0XA10 increases the proliferation of early progenitor cells and can lead to the development of myeloid leukemia. To study the effects of H0XA10 on primitive hematopoietic progenitors in more detail, transgenic mice were generated with regulatable H0XA10 expression. The transgenic mouse model, referred to as tetO-HOXA10, contains theH0XA10 gene controlled by a tetracycline-responsive element and a minimal promoter. Thus, the expression of H0XA10 is inducible and reversible depending on the absence or presence of tetracycline or its analog, doxycycline. A retroviral vector containing the tetracycline transactivator gene (tTA) was used to induce expression of the H0XA10 gene in bone marrow cells from the transgenic mice. Reverse transcription–polymerase chain reaction analysis confirmed regulatable H0XA10 expression in several transgenic lines. H0XA10 induction led to the formation of hematopoietic colonies containing blastlike cells and megakaryocytes. Moreover, the induction of H0XA10 resulted in significant proliferative advantage of primitive hematopoietic progenitors (spleen colony-forming units [CFU-S12]), which was reversible on withdrawal of induction. Activation of H0XA10 expression intet0-H0XA10 mice will therefore govern proliferation of primitive myeloid progenitors in a regulated fashion. This novel animal model can be used to identify the target genes of HOXA10 and better clarify the specific role of HOXA10 in normal and malignant hematopoiesis.
The human erythropoietin receptor gene rescues erythropoiesis and developmental defects in the erythropoietin receptor null mouse
Authors: Yu Xiaobing , Lin Chyuan-Sheng , Costantini Frank , Noguchi Constance Tom
Published: July 2002

Erythropoietin and its receptor are required for definitive erythropoiesis and maturation of erythroid progenitor cells. Mice lacking the erythropoietin receptor exhibit severe anemia and die at about embryonic day 13.5. This phenotype can be rescued by the human erythropoietin receptor transgene. Animals expressing only the human erythropoietin receptor survived through adulthood with normal hematologic parameters and appeared to respond appropriately to induced anemic stress. In addition to restoration of erythropoiesis during development, the cardiac defect associated with embryos lacking the erythropoietin receptor was corrected and the increased apoptosis in fetal liver, heart, and brain in the erythropoietin receptor null phenotype was markedly reduced. These studies indicate that no species barrier exists between mouse and human erythropoietin receptor and that the human erythropoietin receptor transgene is able to provide specific expression in hematopoietic and other selected tissues to rescue erythropoiesis and other organ defects observed in the erythropoietin receptor null mouse.
p53 dysfunction in B-cell chronic lymphocytic leukemia: inactivation of ATM as an alternative toTP53 mutation
Authors: Pettitt Andrew R. , Sherrington Paul D. , Stewart Grant , Cawley John C. , Taylor A. Malcolm R. , Stankovic Tatjana
Published: July 2002

The well-established association between TP53 mutations and adverse clinical outcome in a range of human cancers reflects the importance of p53 protein in regulating tumor-cell growth and survival. Although it is theoretically possible for p53 dysfunction to arise through mechanisms that do not involve TP53 mutation, such a phenomenon has not previously been demonstrated in a sporadic tumor. Here, we show that p53 dysfunction in B-cell chronic lymphocytic leukemia (CLL) can occur in the absence of TP53 mutation and that such dysfunction is associated with mutation of the gene encoding ATM, a kinase implicated in p53 activation. Forty-three patients with CLL were examined for p53 dysfunction, as detected by impaired up-regulation of p53 and of the p53-dependent protein p21CIP1/WAF1 after exposure to ionizing radiation (IR). Thirty (70%) patients had normal p53 responses and underwent progressive IR-induced apoptosis. In 13 (30%) patients, p21 up-regulation was markedly impaired, indicating p53 dysfunction. Six (14%) of these patients with p53 dysfunction had increased baseline levels of p53, were found to have TP53 mutations, and were completely resistant to IR-induced apoptosis. In the other 7 (16%) patients with p53 dysfunction, IR-induced p53 up-regulation and apoptosis were markedly impaired, but baseline levels of p53 were not increased, and no TP53 mutations were detected. Each of these patients was found to have at least one ATM mutation, and a variable reduction in ATM protein was detected in all 4 patients examined. This is the first study to provide a direct demonstration that p53 dysfunction can arise in a sporadic tumor by a mechanism that does not involve TP53 mutation.
Dynamic molecular modeling of pathogenic mutations in the spectrin self-association domain
Authors: Zhang Zhushan , Weed Scott A. , Gallagher Patrick G. , Morrow Jon S.
Published: July 2002

Disruption of spectrin self-association underlies many inherited hemolytic disorders. Using dynamic modeling and energy minimization, the 3-dimensional structure of the self-association domain has been estimated in human erythrocyte spectrin and the structural consequences of 17 elliptogenic mutations determined. The predicted structure of the normal self-association domain was remarkably similar to the crystal structure of the Drosophila α-spectrin 14th repeat unit, despite replacement in the human sequence of over 70% of the amino acids relative to fly spectrin, including 2 prolines in the human sequence that appear in helical regions of the fly structure. The predicted structure placed all hydrophilic residues at the surface and identified 4 salt bridges, 9 hydrophobic interactions, and 4 H-bonds that stabilize the native self-association unit. Remarkably, every pathologic point mutation, including seemingly conservative substitutions such as G for A, A for V, or K for R (single-letter amino acid codes), led to conformational rearrangements in the predicted structure. The degree of structural disruption, as measured by root-mean-square deviation of the predicted backbone structure from theDrosophila structure, correlated strongly with the severity of clinical disease associated with each mutation. This approach thus enables an accurate prediction, from the primary sequence, of the clinical consequences of specific point mutations in spectrin. The 3-dimensional structure of the self-association domain derived here is likely to be accurate. It provides a powerful heuristic model for understanding how point mutations disrupt cytoskeletal function in a variety of hemolytic disorders.
HIV gp120 receptors on human dendritic cells
Authors: Turville Stuart G. , Arthos Jim , Mac Donald Kelli , Lynch Garry , Naif Hassan , Clark Georgina , Hart Derek , Cunningham Anthony L.
Published: July 2002

Dendritic cells (DCs) are important targets for human immunodeficiency virus (HIV) because of their roles during transmission and also maintenance of immune competence. Furthermore, DCs are a key cell in the development of HIV vaccines. In both these settings the mechanism of binding of the HIV envelope protein gp120 to DCs is of importance. Recently a single C-type lectin receptor (CLR), DC-SIGN, has been reported to be the predominant receptor on monocyte-derived DCs (MDDCs) rather than CD4. In this study a novel biotinylated gp120 assay was used to determine whether CLR or CD4 were predominant receptors on MDDCs and ex vivo blood DCs. CLR bound more than 80% of gp120 on MDDCs, with residual binding attributable to CD4, reconfirming that CLRs were the major receptors for gp120 on MDDCs. However, in contrast to recent reports, gp120 binding to at least 3 CLRs was observed: DC-SIGN, mannose receptor, and unidentified trypsin resistant CLR(s). In marked contrast, freshly isolated and cultured CD11c+ve and CD11c−ve blood DCs only bound gp120 via CD4. In view of these marked differences between MDDCs and blood DCs, HIV capture by DCs and transfer mechanisms to T cells as well as potential antigenic processing pathways will need to be determined for each DC phenotype.
Erythropoietin expression in primary rat Sertoli and peritubular myoid cells
Authors: Magnanti Massimo , Gandini Orietta , Giuliani Laura , Gazzaniga Paola , Marti Hugo H. , Gradilone Angela , Frati Luigi , Aglianò Anna Maria , Gassmann Max
Published: July 2002

Kidney and liver are the major organs of erythropoietin (Epo) synthesis. However, Epo messenger RNA (mRNA) has been detected in several organs, such as brain, lung, and testis. Furthermore, functional Epo receptors have been demonstrated on different cell types, including rat Leydig cells. The aim of the study was to identify testicular cells expressing Epo mRNA and to quantitate its levels by competitive reverse transcriptase–polymerase chain reaction (RT-PCR). Besides whole testis, Epo transcripts were found in Sertoli and peritubular myoid cells, while no signal was detected in Leydig cells. Exposure of Sertoli cells to CoCl2 led to an increase of Epo mRNA level. Semiquantitative competitive RT-PCR presented an increase in the level of Epo mRNA in Sertoli cells stimulated by follicle-stimulating hormone, while exposure of peritubular myoid cells cultures to testosterone reduced Epo mRNA expression. Due to the blood-testis barrier, basal expression of Epo suggests a not yet defined function of this hormone in testis.
Trends in Maternal Death Post-Dobbs v Jackson Women’s Health
Authors: Stevenson Amanda Jean , Root Leslie
Published: August 2024

This cross-sectional study examines monthly maternal deaths after the Dobbs v Jackson Women’s Health decision.
Race and Ethnicity and Diagnostic Testing for Common Conditions in the Acute Care Setting
Authors: Ellenbogen Michael I. , Weygandt P. Logan , Newman-Toker David E. , Anderson Andrew , Rim Nayoung , Brotman Daniel J.
Published: August 2024

Importance

Overuse of diagnostic testing is pervasive, but the extent to which it varies by race and ethnicity in the acute care setting is poorly understood.

Objective

To use a previously validated diagnostic intensity index to evaluate differences in diagnostic testing rates by race and ethnicity in the acute care setting, which may serve as a surrogate for diagnostic test overuse.

Design, Setting, and Participants

This was a cross-sectional study of emergency department (ED) discharges, hospital observation stays, and hospital admissions using administrative claims among EDs and acute care hospitals in Kentucky, Maryland, North Carolina, and New Jersey, from 2016 through 2018. The diagnostic intensity index pairs nonspecific principal discharge diagnoses (nausea and vomiting, abdominal pain, chest pain, and syncope) with related diagnostic tests to estimate rates of nondiagnostic testing. Adults with an acute care encounter with a principal discharge diagnosis of interest were included. Data were analyzed from January to February 2024.

Exposure

Race and ethnicity (Asian, Black, Hispanic, White, other [including American Indian, multiracial, and multiethnic], and missing).

Main Outcomes and Measures

Receipt of a diagnostic test. Generalized linear models with a hospital-specific indicator variable were estimated to calculate the adjusted odds ratio of receiving a test related to the principal discharge diagnosis by race and ethnicity, controlling for primary payer and zip code income quartile.

Results

Of 3 683 055 encounters (1 055 575 encounters [28.7%] for Black, 300 333 encounters [8.2%] for Hispanic, and 2 140 335 encounters [58.1%] for White patients; mean [SD] age of patients with encounters, 47.3 [18.8] years; 2 233 024 encounters among females [60.6%]), most (2 969 974 encounters [80.6%]) were ED discharges. Black compared with White patients discharged from the ED with a diagnosis of interest had an adjusted odds ratio of 0.74 (95% CI, 0.72-0.75) of having related diagnostic testing. No other racial or ethnic disparities of a similar magnitude were observed in any acute care settings.

Conclusions and Relevance

In this study, White patients discharged from the ED with a nonspecific diagnosis of interest were significantly more likely than Black patients to receive related diagnostic testing. The extent to which this represents diagnostic test overuse in White patients vs undertesting and missed diagnoses in Black patients deserves further study.
Commissioning and validation of a single photon beam model in RayStation for multiple matched Elekta Linacs
Authors: Su Lin , Huang Ellen , Miles Devin A. , Farjam Reza , Marsh Ian R. , Li Qiongge , Moore Joseph A. , McNutt Todd R. , Ding Kai , Wang Ken Kang‐Hsin , Robinson Adam , Kuri Gregory , Seabrease Richard , Adam David P. , Oglesby Ryan , Shen Bin , Wu Binbin , Lee Junghoon , Jia Xun , Han‐Oh Sarah
Published: August 2024

Purpose

A single treatment planning system (TPS) model for matched linacs provides flexible clinical workflows from patient treatment to intensity‐modulated radiation therapy (IMRT) quality assurance (QA) measurement. Since general guidelines for building a single TPS model and its validation for matched linacs are not well established, we present our RayStation photon TPS modeling strategy for matched Elekta VersaHD linacs.

Method

The four linacs installed from 2013 to 2020 were matched in terms of Percent Depth Dose (PDD), profile, output factor and wedge factors for 6‐MV, 10‐MV, 15‐MV, and 6‐MV‐FFF, and maintained following TG‐142 recommendations until RayStation commissioning. The RayStation single model was built to represent all four linacs within the tolerance limits recommended by MPPG‐5.a. The comprehensive validation tests were performed for one linac following MPPG‐5.a and TG‐119 guidelines, and spot checks for the other three. Our TPS modeling/validation method was evaluated by re‐analyzing the previous 103 patient‐specific IMRT/volumetric modulated arc therapy (VMAT) QA measurements with the calculated planar doses by the single model in comparison with the analysis results using four individual Pinnacle TPS models.

Results

For all energies, our single model PDDs were within 1% agreement of the four‐linac commissioning measurements. The MPPG‐5.a validation tests from 5.1 through 7.5 and all TG‐119 measurements passed within the recommended tolerance limits. The IMRT QA results (mean ± standard deviation) for RayStation single model versus Pinnacle individual models were 98.9% ± 1.3% and 98.0% ± 1.4% for 6‐MV, 99.9% ± 0.1% and 99.1% ± 1.9% for 10‐MV, and 98.2% ± 1.3% and 97.9% ± 1.8% for 6‐MV‐FFF, respectively.

Conclusion

We successfully built and validated a single photon beam model in RayStation for four Elekta Linacs. The proposed new validation methods were proven to be both efficient and effective.
Implementation of optically simulated luminescent dosimeter for quality control of gamma ray dose of an accelerator‐based neutron source
Authors: Hu Naonori , Nakamura Taiki , Kataura Ryusuke , Suga Keita , Mukawa Tetsuya , Akita Kazuhiko , Sasaki Akinori , Nojiri Mai , Matsubayashi Nishiki , Takata Takushi , Tanaka Hiroki , Nihei Keiji , Ono Koji
Published: August 2024

Background

Neutron beams utilized for performing BNCT are composed of a mixture of neutrons and gamma rays. Although much of the dose delivered to the cancer cells comes from the high LET particles produced by the boron neutron capture reaction, the dose delivered to the healthy tissues from unwanted gamma rays cannot be ignored. With the increase in the number of accelerators for BNCT, a detector system that is capable of measuring gamma ray dose in a mixed neutron/gamma irradiation field is crucial. Currently, BeO TLDs encased in quartz glass are used to measure gamma ray dose in a BNCT irradiation field. However, this type of TLD is no longer commercially available. A replacement dosimetry system is required to perform the recommended ongoing quality assurance of gamma ray measurement for a clinical BNCT system.

Purpose

The purpose of this study is to evaluate the characteristics of a BeO OSLD detector system under a mixed neutron and gamma ray irradiation field and to assess the suitability of the system for routine quality assurance measurements of an accelerator‐based BNCT facility.

Methods

The myOSLD system by RadPro International GmbH was evaluated using the accelerator‐based neutron source designed for clinical BNCT (NeuCure BNCT system). The readout constancy, linearity, dose rate effect, and fading effect of the OSLD were evaluated. Free‐in‐air and water phantom measurements were performed and compared with the TLD results and Monte Carlo simulation results. The PHITS Monte Carlo code was used for this study.

Results

The readout constancy was found to be stable over a month‐long period and similar to the TLD results. The OSLD readout signal was found to be linear, with a high coefficient of determination (R2 ≥ 0.999) up to a proton charge of 3.6 C. There was no significant signal fading or dose rate dependency. The central axis depth dose and off‐axis dose profile measurements agreed with both the TLD and Monte Carlo simulation results, within one standard deviation.

Conclusion

The myOSLD system was characterized using an accelerator system designed for clinical BNCT. The experimental measurements confirmed the OSLD achieved similar, if not superior to, the currently utilized dosimetry system for routine QA of an accelerator‐based BNCT system. The OSLD system would be a suitable replacement for the current TLD system for performing routine QA of gamma ray dose measurement in a BNCT irradiation field.
Key Strategies for Continuous Seawater Splitting for Hydrogen Production: From Principles and Catalyst Materials to Electrolyzer Engineering
Authors: Du Hanxiao , Wang Xunlu , Song Junnan , Ran Nian , Ma Junqing , Wang Jiacheng , Liu Jianjun
Published: August 2024

Due to the high cost of ultra‐pure water supply and the mismatch between water sources and renewable energy distribution, the large‐scale production of green hydrogen through seawater electrolysis has generated significant interest. This presents an attractive potential technology within the framework of carbon‐neutral energy production. However, owing to the complex composition of seawater, particularly the competitive oxidation reactions and corrosion issues involving Cl−, seawater electrolysis has suffered from low selectivity and poor stability in oxygen evolution reaction (OER), which severely impact the efficiency of hydrogen production and hinder the practical applications. To further promote in‐depth research and practical applications of seawater electrolysis, this review introduces the principles, key advantages, and challenges of seawater electrolysis. Specifically, the design strategies are categorized for highly active OER electrocatalysts for seawater electrolysis, including catalyst design, design of chemical reaction systems, and other special process design. To ensure long‐term operational stability of seawater electrolysis, various strategies such as employing self‐supporting materials, surface protection strategies, and electrolyzer design, are discussed. Finally, current challenges and future prospects for the industrialization of seawater electrolysis are proposed and discussed. It is expected that this review provides new insights for large‐scale seawater‐based hydrogen production in the future.
OH‐Induced Surface Reconstitution in Single Atoms and Clusters Integrated Electrocatalysts for Self‐Adaptive Oxygen Electrocatalysis
Authors: Qi Jiawei , Yu Litao , Gan He , Li Huan , Guo Songde , Wang Dun , Chen Zilong , Zhao Chunming , Han Cuiping , Cheng Hui‐Ming
Published: August 2024

The integration of atom clusters and single atoms into a unified system represents a desirable approach for attaining enhanced catalytic performance. Nonetheless, the controllable synthesis of a single‐atom and nanocluster integrated system (SA‐NC) faces considerable challenges, and the mechanisms underlying the catalytic activity remain poorly understood. In this research, a cobalt‐based catalyst containing both coordinatively unsaturated single‐atom (CoN3) and small nanoclusters (Co@SA‐NC) is synthesized. The Co@SA‐NC not only facilitates charge and mass transfer due to the interconnected long‐range micromorphology, thus endowing efficient oxygen electrocatalytic reaction (ORR/OER), but also undergoes surface reconfiguration upon OH adsorption at high potentials in alkaline ORR/OER conditions. More appealingly, this OH‐involved reconfigured adaptive structure promotes optimization of energy barriers owing to the dynamic regulation from the bridged OH between Co single‐atom and cluster in the whole reaction process. Specific to the application metrics, a zinc–air battery assembled using the Co@SA‐NC catalyst exhibit targeted power density enhancement with 270 mW cm−2 in an alkaline medium. This work offers an effective insight into the study of SA‐NC catalytic reaction pathways for efficient ORR/OER catalysis.
Molecular Engineering of Multivariate Porous Aromatic Frameworks for Recovery of Dispersed Uranium Resources
Authors: Ma Yue , Liu Lu , Zhao Shilei , Xu Xiaozhao , Wang Yue , Zhang Yilei , Rong Huazhen , Yuan Yihui , Wang Ning
Published: August 2024

Uranium plays an indispensable role in the sustainable development of nuclear industry, and the recovery of uranium from nuclear wastewater is one way to solve the shortage of uranium resources. However, the recovery of uranium resources from nuclear wastewater remains a challenge due to the interfere of coexisting ions. Herein, ratios of the adsorption group and photocatalytic enrichment group are well‐designed and controllably assembled into the porous aromatic frameworks (PAFs) using molecular engineering strategy to realize high uranium recovery efficiency and high resistance to interfering ions. The optimally coordinated multivariate PAF material PAF‐AN2T8‐AO exhibits bifunctions of adsorption and photocatalytic enrichment and thus, achieves high enrichment selectivity and high uranium recovery efficiency of 99% under simulated sunlight irradiation. Compared to PAFs with only adsorption group or photocatalytic group, the uranium recovery capacity of the optimized PAF is enhanced by 1.2 times and 2.3 times, respectively. Mechanistic studies reveal that the product of photocatalytic uranium on PAF‐AN2T8‐AO is air‐stabilized solid crystal metastudtite ((UO2)O2∙2H2O). This work provides a guiding method for designing adsorption‐photocatalytic bifunctional materials and proposes a more environmentally adaptable strategy for dispersed uranium resource recovery.