julilili42/papers huggingface dataset:
Nitridoborates of the Lanthanides: Synthesis, Structure Principles, and Properties of a New Class of Compounds
2002-09-16

Investigations of the nitridoborates of lanthanides (Ln) have progressed significantly during the last few years. New compounds have been synthesized and characterized and are presented here together with some of their properties. Currently two distinct methods serve for the preparation of nitridoborate compounds; either hexagonal boron nitride undergoes a fragmentation through the reaction with LnN, or dinitridoborate ions are converted into other nitridoborate ions. Lanthanide nitridoborates contain molecular anions such as [BN]n−, [BN2]3−, [B2N4]8−, [B3N6]9−, and [BN3]6− which may occur in combinations with other nitridoborates or with additional nitride ions. In crystal structures of lanthanide nitridoborates these anions are arranged in layers and are surrounded by metal atoms in a characteristic fashion. Terminal N atoms are capped by metal atoms forming a square-pyramid, and B atoms prefer a trigonal-prismatic environment of metal atoms. Nitridoborates form saltlike as well as metal-rich compounds and have the potential to show a lot of what are considered to be important solid-state properties, thus they have a good chance to establish their position within the group of relevant materials.
Synthesis and Optical Limiting Properties of Axially Bridged Phthalocyanines: [(tBu4PcGa)2O] and [(tBu4PcIn)2O]
2002-09-16

Highly soluble [(tBu(4)PcM)(2)O] phthalocyanine dimers (M=Ga(III) (3), In(III) (4)) were prepared by the reaction of [tBu(4)PcMCl] (M=Ga(III) (1), In(III) (2)) with excess of concentrated H(2)SO(4) at -20 degrees C. The Mbond;Obond;M linkages in 3 and 4 are not stable against concentrated H(2)SO(4) at room temperature, 6 n HCl at reflux, or during isolation under column chromatographic conditions (e.g. silica gel/toluene). The stability of 3 in solution is considerably higher than that of 4. The mu-oxo-bridged phthalocyanine dimers 3 and 4 have a more intense photoluminescence emission in the red region than the monomers 1 and 2. The gallium phthalocyanines 1 and 3 have fluorescence lifetimes of a few nanoseconds, while those of the indium phthalocyanines 2 and 4 last for only several hundred picoseconds. Comparison of the fluorescence lifetimes of monomers 1 and 3 with dimers 2 and 4, reveals that the dimers have longer lifetimes of the excited singlet states. The transient absorption spectrum is similar for all of the compounds, and the transient absorption band at about 520 nm, observed by nanosecond laser irradiation, can be assigned to the transition from the lowest triplet excited state to the upper triplet excited states (T-T absorption). The magnitude of the optical limiting exhibited by 1, 2, 3, and 4 in toluene at 532 nm laser pulse irradiation is in the order: 4>3>2>1 [corrected]. The values of the imaginary third-order nonlinear susceptibility Im[chi((3))] of the above compounds at 532 nm in toluene are also reported. These results demonstrate that these compounds are candidates for optical limiting applications.
Tools for the analysis of dose optimization: II. Sensitivity analysis
2002-09-16

Dose optimization requires that the treatment goals be specified in a meaningful manner, but also that alterations to the specification lead to predictable changes in the resulting dose distribution. Within the framework of constrained optimization, it is possible to devise a tool that quantifies the impact on the objective of target volume coverage of any change to a dosimetric constraint of normal tissue or target dose homogeneity. This sensitivity analysis relies on properties of the Lagrange function that is associated with the constrained optimization problem, but does not depend on the method used to solve this problem. It is useful particularly in cases with multiple target volumes and critical normal structures, where constraints and objectives can interact in a non-intuitive manner.
ULTRA Loaded Resins Based on the Cross-Linking of Linear Poly(ethylene imine). Improving the Atom Economy of Polymer-Supported Chemistry
2002-09-16

In the Communication by J. Rademann and M. Barth in issue 16, 2002, pp. 2975–2978, the single-letter codes for the amino acids of peptide 15 (H-Trp-Glu-Ile-His-Asn-Ala-Cys-His-Thr-Ser-Thr-Ala-Gly-OH), WEIHNACHTSTAG, was erroneously printed as “Christmas”. The editorial office apologizes for this error.
Pavlovian conditioning of opioid and nonopioid pain inhibitory mechanisms in humans
2002-09-17

Learning processes such as respondent or Pavlovian conditioning are believed to play an important role in the development of chronic pain, however, their influence on the inhibition of pain has so far not been assessed in humans. The purpose of this study was the demonstration of Pavlovian conditioning of stress‐induced analgesia in humans and the determination of its opioid mediation. In a differential classical conditioning paradigm two different auditory stimuli served as conditioned stimuli and mental arithmetic plus white noise as unconditioned stimulus. Subsequent to four conditioning trials naloxone or placebo was applied in a double‐blind fashion on two test days. Both pain threshold and pain tolerance showed conditioned stress‐induced analgesia. Pain tolerance was affected by naloxone whereas pain threshold was not. The data of this study show that stress analgesia can be conditioned in humans and that it is at least partially mediated by the endogenous opioid system. Learning processes also influence pain inhibitory processes in humans and this effect might play a role in the development of chronic pain.
Final shift for call/cc:
2002-09-17

We present a direct implementation of the shift and reset control operators in the SFE system. The new implementation improves upon the traditional technique of simulating shift and reset via callcc. Typical applications of these operators exhibit space savings and a significant overall performance gain. Our technique is based upon the popular incremental stack/heap strategy for representing continuations. We present implementation details as well as some benchmark measurements for typical applications.
Final shift for call/cc:
2002-09-17

We present a direct implementation of the shift and reset control operators in the SFE system. The new implementation improves upon the traditional technique of simulating shift and reset via callcc . Typical applications of these operators exhibit space savings and a significant overall performance gain. Our technique is based upon the popular incremental stack/heap strategy for representing continuations. We present implementation details as well as some benchmark measurements for typical applications.
Long-term follow-up on a patient with incomplete POEMS syndrome undergoing high-dose therapy and autologous blood stem cell transplantation
2002-09-18

be associated with clinically significant autoimmunity. 1,3,8In contrast, in children with classical SCID in whom no T lymphocytes are present, clinical features suggestive of autoimmunity are more likely to be due to the direct consequences of infections, as the complete lack of T lymphocytes prevents the development of an autoimmune response.Elhasid et al's second patient with T Ϫ B ϩ NK ϩ SCID developed a consumptive thrombocytopenia that did not respond to steroids or high-dose intravenous immunoglobulin (IVIG) therapy, but the patient did finally respond to matchedsibling bone marrow transplantation.Considering the temporal relationship to the other symptoms of viral infection, it is likely that rather than the thrombocytopenia being ITP, it was directly caused by the virus infection.As emphasized in our review, immunomodulation and treatment of infection is often a better treatment strategy than immunosuppression alone in children with primary immunodeficiency and suspected autoimmune phenomena, as immunosuppression may exacerbate the underlying infectious disease and result in increased morbidity and mortality.Finally, as stated in our review and reiterated by Elhasid et al, in children with an underlying PID, autoimmunity and the inability to effectively eradicate infection should both be viewed as features of dysregulated immunity.Correcting the underlying immunodeficiency by stem cell transplantation often corrects both clinical problems.Although stem cell transplantation had in the past been considered, but not often used, as a possible treatment option for autoimmunity where no underlying primary immunodeficiency can be found, advances in the safety and effectiveness of this therapy have recently lead to a revival in interest in this treatment modality. 9
Two types of ipsilateral reorganization in congenital hemiparesis: A TMS and fMRI study
2002-09-20

Reorganization after early brain injuries is not only determined by the maturational stage of the CNS at the time of the insult (timing), but also by the structural properties, location and extent of the lesion. This study addresses the impact of different lesion extents on the type of reorganization induced in a cohort of patients with lesions of uniform structure and location (unilateral periventricular defects) and similar timing (early third trimester of pregnancy). Twelve young adult patients with congenital hemiparesis and 10 age-matched controls were studied. The severity of structural damage to hand motor projections of the cortico-spinal tract was assessed on semi-coronal MRI reconstructions along anatomical landmarks of cortico-spinal tract somatotopy. The functional integrity of these crossed cortico-spinal projections in the affected hemisphere, as well as the presence of any abnormal ipsilateral projections to the paretic hand, was examined by transcranial magnetic stimulation (TMS). Cortical activation during simple voluntary hand movements was studied by functional MRI (fMRI). Patients with small lesions (SL; n = 4) and only mild hand motor impairment possessed intact crossed cortico-spinal projections to the paretic hand, whereas no motor response could be elicited by TMS of the affected hemisphere in those with large lesions (LL; n = 6) and more severe hand motor impairment. Evidence for compensatory recruitment of the unaffected hemisphere was found in both subgroups. In the SL group, fMRI demonstrated ipsilateral activation of premotor areas, without any abnormal projections to the paretic hand originating from these sites. In the LL group, such abnormal ipsilateral projections to the paretic hand were indeed found, and fMRI confirmed cortical activation of an abnormal ipsilateral hand motor representation in the primary sensorimotor region of the unaffected hemisphere. Two patients with intermediate-sized lesions presented combined features of both groups (SL, LL). In conclusion, this study provides evidence that the type of cortico-spinal reorganization depends on the extent of the brain lesion. We propose that involvement of the ipsilateral hemisphere can be (i) of the premotor type, i.e. without ipsilateral motor projections but with significant activation of ipsilateral premotor areas, or (ii) of the primary motor type, i.e. with abnormal ipsilateral cortico-spinal projections to the paretic hand.
Paternity frequency and maternity of males in some stingless bee species
2002-09-23

Abstract In monogynous hymenopteran societies, the number of mates of a queen strongly influences the potential for conflict between workers and queens over the maternity of males. Queens always ‘prefer’ their own sons to sons of workers, regardless of queen mating frequency. When a queen mates once, workers are more closely related to, and therefore are expected to prefer, their own sons and then sons of sisters to sons of the queen. However, if effective paternity frequency exceeds 2, workers on average should prefer queen‐produced males to males produced by their sisters. We studied the queen mating frequency of seven stingless bee species: the Mexican species Scaptotrigona mexicana , S. pectoralis and the Australian species Austroplebeia symei , Trigona clypearis , T. hockingsi , T. mellipes and T. sapiens . We then determined whether males arise from eggs laid by workers or queens in A. symei , T. clypearis , T. hockingsi and T. mellipes . We show that all seven species investigated are most likely singly mated and that the queen dominates reproduction. This indicates that the queen's mating frequency alone does not determine whether workers or the queen produces the males.
Quantum Effects with an X-Ray Free-Electron Laser
2002-09-24

A quantum kinetic equation coupled with Maxwell's equation is used to estimate the laser power required at an x-ray free-electron laser (XFEL) facility to expose intrinsically quantum effects in the process of QED vacuum decay via spontaneous pair production. A 9 -TW-peak XFEL laser with photon energy of 8.3 keV could be sufficient to initiate particle accumulation and the consequent formation of a plasma of spontaneously produced pairs. The evolution of the particle number in the plasma will exhibit non-Markovian aspects of the strong-field pair production process, and the plasma's internal currents will generate an electric field whose interference with that of the laser leads to plasma oscillations.
Large-Scale Vortices in Protoplanetary Disks: On the Observability of Possible Early Stages of Planet Formation
2002-09-24

We investigate the possibility of mapping large-scale anti-cyclonic vortices, resulting from a global baroclinic instability, as pre-cursors of planet formation in proto-planetary disks with the planned Atacama Large Millimeter Array (ALMA). On the basis of three-dimensional radiative transfer simulations, images of a hydrodynamically calculated disk are derived which provide the basis for the simulation of ALMA. We find that ALMA will be able to trace the theoretically predicted large-scale anti-cyclonic vortex and will therefore allow testing of existing models of this very early stage of planet formation in circumstellar disks.
Surface embedding, topology and dualization for spin networks
2002-09-24

Spin networks are graphs derived from 3nj symbols of angular momentum. The surface embedding, the topology and dualization of these networks are considered. Embeddings into compact surfaces include the orientable sphere S 2 and the torus T, and the not orientable projective space P 2 and Klein’s bottle K. Two families of 3nj graphs admit embeddings of minimal genus into S 2 and P 2. Their dual 2-skeletons are shown to be triangulations of these surfaces. 1 Spin networks. Spin networks were introduced by Penrose [13] as a purely combinatorial description of the geometry of spacetime. A spin network has a graph Γ of 3n edges which represents an invariant formed from 3n angular momenta j. Γ is connected and at any vertex has degree 3. When j-values are attached to Γ = Γ(3nj) which fulfill the intertwining rules at each vertex, the value of the corresponding 3nj invariant can be computed and used in the theory of spin networks. A systematic description and evaluation of the 3nj invariants is given by Yutsis et al. in [19]. Motivated by the discretization of a Riemannian surface to avoid infinities in Einstein action, Ponzano and Regge [14] extensively used 3nj symbols and their geometrical interpretation. Hasslacher and Perry [6] proved that Ponzano Regge discretization is a particular case of spin networks. The development of this subject is reviewed in [16]. The spin network approach uses combinatorial properties of a set of relations to give an interpretation of the structure of space. In the present paper we explore a similar correspondence between combinatorial properties of graphs and their embedding in 1 compact surfaces. Our method is in line with algebraic topology and provides a more rigorous setting for the intuitive embedding of 3nj symbols given by Ponzano and Regge. The philosophical background to a spin network interpretation goes back to the relational theory of space and time proposed by Leibniz. One of the authors (M.L.) has developed in [10],[11] a fundamental theory based on Leibniz ’ ideas to give an interpretation of discrete models of space and time.
Prostate stem cell antigen: Identification of immunogenic peptides and assessment of reactive CD8+ T cells in prostate cancer patients
2002-09-25

Abstract Identification of TAAs recognized by CD8 + CTLs paved the way for new concepts in cancer therapy. In view of the heterogeneity of tumors and their diverse escape mechanisms, CTL‐based cancer therapy largely depends on an appropriate number of TAAs. In prostate cancer, the number of antigens defined as suitable targets of CTLs remains rather limited. PSCA is widely distributed in prostate cancer. In this report, we define immunogenic peptides of PSCA which are recognized by circulating CD8 + T cells from prostate cancer patients and able to activate CTLs in vitro. Screening the amino acid sequence of PSCA for peptides containing a binding motif for HLA‐A*0201 resulted in 8 candidate peptides. Specificity and affinity of peptide binding were verified in a competition assay. Frequencies of CD8 + T lymphocytes reactive against selected epitopes were determined in the blood of prostate cancer patients using the ELISPOT assay. Increased frequencies were revealed for CD8 + T cells recognizing the peptides ALQPGTALL and AILALLPAL. CTLs from prostate cancer patients were raised against these 2 peptides in vitro when presented by autologous DCs. They specifically recognized peptide‐pulsed T2 target cells and prostate cancer cells that were HLA‐A*0201‐ and PSCA‐positive, indicating that these peptides were naturally generated by tumor cells. These data suggest that PSCA is a promising target for the immunotherapy of prostate cancer. © 2002 Wiley‐Liss, Inc.
Inactivation of the 2‐oxo acid dehydrogenase complexes upon generation of intrinsic radical species
2002-09-27

Self‐regulation of the 2‐oxo acid dehydrogenase complexes during catalysis was studied. Radical species as side products of catalysis were detected by spin trapping, lucigenin fluorescence and ferricytochrome c reduction. Studies of the complexes after converting the bound lipoate or FAD cofactors to nonfunctional derivatives indicated that radicals are generated via FAD. In the presence of oxygen, the 2‐oxo acid, CoA‐dependent production of the superoxide anion radical was detected. In the absence of oxygen, a protein‐bound radical concluded to be the thiyl radical of the complex‐bound dihydrolipoate was trapped by α‐phenyl‐ N ‐ tert ‐butylnitrone. Another, carbon‐centered, radical was trapped in anaerobic reaction of the complex with 2‐oxoglutarate and CoA by 5,5′‐dimethyl‐1‐pyrroline‐ N ‐oxide (DMPO). Generation of radical species was accompanied by the enzyme inactivation. A superoxide scavenger, superoxide dismutase, did not protect the enzyme. However, a thiyl radical scavenger, thioredoxin, prevented the inactivation. It was concluded that the thiyl radical of the complex‐bound dihydrolipoate induces the inactivation by 1e – oxidation of the 2‐oxo acid dehydrogenase catalytic intermediate. A product of this oxidation, the DMPO‐trapped radical fragment of the 2‐oxo acid substrate, inactivates the first component of the complex. The inactivation prevents transformation of the 2‐oxo acids in the absence of terminal substrate, NAD + . The self‐regulation is modulated by thioredoxin which alleviates the adverse effect of the dihydrolipoate intermediate, thus stimulating production of reactive oxygen species by the complexes. The data point to a dual pro‐oxidant action of the complex‐bound dihydrolipoate, propagated through the first and third component enzymes and controlled by thioredoxin and the (NAD + + NADH) pool.
Diffusion through channel derivatives of the Escherichia coli FhuA transport protein
2002-09-27

FhuA is a multifunctional protein in the outer membrane of Escherichia coli that actively transports [Fe 3+ ]ferrichrome, the antibiotics albomycin and rifamycin CGP 4832, and mediates sensitivity of cells to the unrelated phages T5, T1, φ80 and UC‐1, and to colicin M and microcin J25. The energy source of active transport is the proton motive force of the cytoplasmic membrane that is required for all FhuA functions except for infection by phage T5. The FhuA crystal structure reveals 22 antiparallel transmembrane β‐strands that form a β‐barrel which is closed by a globular N‐terminal domain. FhuA still displays active transport and sensitivity to all ligands except microcin J25 when the globular domain (residues 5–160) is excised and supports weakly unspecific diffusion of substrates across the outer membrane. Here it is shown that isolated FhuAΔ5–160 supported diffusion of ions through artificial planar lipid bilayer membranes but did not form stable channels. The double mutant FhuAΔ5–160 Δ322–336 lacking in addition to the globular domain most of the large surface loop 4 which partially constricts the channel entrance, displayed an increased single‐channel conductance but formed no stable channels. It transported in vivo [Fe 3+ ]ferrichrome with 45% of the rate of wild‐type FhuA and did not increase sensitivity of cells to antibiotics. In contrast, a second FhuA double mutant derivative which in addition to the globular domain contained a deletion of residues 335–355 comprising one‐third of surface loop 4 and half of the transmembrane β‐strand 8 formed stable channels in lipid bilayers with a large single‐channel conductance of 2.5 nS in 1 m KCl. Cells that synthesized FhuAΔ5–160 Δ335–355 showed an increased sensitivity to antibiotics and supported diffusion of maltodextrins, SDS and ferrichrome across the outer membrane. FhuAΔ5–160 Δ335–355 showed no FhuA specific functions such as active transport of [Fe 3+ ]ferrichrome or sensitivity to the other FhuA ligands. It is concluded that FhuAΔ5–160 Δ335–355 assumes a conformation that is incompatible with any of the FhuA functions.
Intimal plaque development and oxidative stress in cholesterol‐induced atherosclerosis in New Zealand rabbits
2002-09-27

Abstract Although oxidative stress is well known in atherogenesis, the origin, nature and kinetics of free radicals involved have not been well described till now. Here, we correlated parameters of oxidative stress with cellular components during induction and stabilization of aortic intimal lesions which were induced in rabbits by feeding a cholesterol‐enriched diet for 6 weeks and a normal diet for further 68 weeks. Plasma lipids, aortic plaque size and composition (macrophages, smooth muscle cells, oxidized LDL by morphometry), as well as aortic radical production (by luminol‐enhanced chemiluminescence and TEMPO‐9AC fluorescence) were measured after various time points. The parameters of oxidative stress were correlated with the different cellular components of the aortic plaques. The plaques increased until week 21, no significant regression was found until week 74, plasma cholesterol was maximal at week 6. Macrophages, oxidized LDL and generation of different species of free radicals were increased during plaque development, yet with different time kinetics. Whereas chemiluminescence correlated only weakly with the amount of intimal macrophages, strong correlations were found between TEMPO fluorescence and smooth muscle cells ( r = 0.4778, P &lt; 0.001) and between macrophages and oxidized LDL ( r = 0.5896, P &lt; 0.0001). Different indicators of oxidative stress were increased during plaque progression and stabilization. However, the various correlations show, that distinct types of reactive species secreted probably from macrophages and smooth muscle cells contribute to oxidative stress in the different phases of plaque development.