cssi/SciSciGPT-SciSciNet huggingface dataset:
Supramolecular photochemistry applied to artificial photosynthesis and molecular logic devices

Supramolecular photochemical systems consist of photochemically active components such as chromophores, electron donors or electron acceptors that are associated via non-covalent or covalent interactions and that interact in some functional way. Examples of interactions are singlet-singlet energy transfer, triplet-triplet energy transfer, photoinduced electron transfer, quantum coherence and spin-spin magnetic interactions. Supramolecular photochemical "devices" may have applications in areas such as solar energy conversion, molecular logic, computation and data storage, biomedicine, sensing, imaging, and displays. This short review illustrates supramolecular photochemistry with examples drawn from artificial photosynthesis, molecular logic, analog photochemical devices and models for avian magnetic orientation.
Cloning of a Mutable bz2 Allele of Maize by Transposon Tagging and Differential Hybridization

Sequences of Bronze2 (Bz2), a maize gene which is required for the synthesis of the purple pigment anthocyanin, have been cloned by combining the techniques of transposon tagging and differential hybridization. First, a mutable bz2 allele (bz2-mu1) was recovered from a Mutator line. The mutation was assumed to result from an insertion of the transposable element Mutator (Mu), which is found in 10-60 copies in Mutator lines. A library was prepared using DNA isolated from bz2-mu1, and a small bank of Mu-specific candidate clones was selected. Because much is known about the genetic requirements for the synthesis of anthocyanin in different tissues, we were able to identify the bz2 clone based on its hybridization to RNA isolated from different bz2 mutants. Only one clone hybridized to RNA isolated from the husks of purple (Bz2, B, Pl) plants but not to RNA isolated from the husks of green (an-bz2-6923, b, pl) plants. Further confirmation was provided by the hybridization pattern of the clone on blots containing DNA from other bz2 mutants. We present a restriction map of the clone, indicating the location and orientation of the 1.4-kbp Mu insert. We identify the transcribed region, the direction of transcription and the location of the 1.4-kbp Mu insert in an independently isolated mutant, bz2-mu2 .
Burst Kinetics and Redox Transformations of the Active Site Manganese Ion in Oxalate Oxidase IMPLICATIONS FOR THE CATALYTIC MECHANISM

Oxalate oxidase (EC 1.2.3.4) catalyzes the oxidative cleavage of oxalate to carbon dioxide and hydrogen peroxide. In this study, unusual nonstoichiometric burst kinetics of the steady state reaction were observed and analyzed in detail, revealing that a reversible inactivation process occurs during turnover, associated with a slow isomerization of the substrate complex. We have investigated the underlying molecular mechanism of this kinetic behavior by preparing recombinant barley oxalate oxidase in three distinct oxidation states (Mn(II), Mn(III), and Mn(IV)) and producing a nonglycosylated variant for detailed biochemical and spectroscopic characterization. Surprisingly, the fully reduced Mn(II) form, which represents the majority of the as-isolated native enzyme, lacks oxalate oxidase activity, but the activity is restored by oxidation of the metal center to either Mn(III) or Mn(IV) forms. All three oxidation states appear to interconvert under turnover conditions, and the steady state activity of the enzyme is determined by a balance between activation and inactivation processes. In O2-saturated buffer, a turnover-based redox modification of the enzyme forms a novel superoxidized mononuclear Mn(IV) biological complex. An oxalate activation role for the catalytic metal ion is proposed based on these results.
A look into the future of interventional radiology for the injured patient.

On 31 August 1966 the seminal ideas that led me to focus my academic career on the treatment of traumatic conditions using miniaturised instruments opened in theatres across the United States. The movie, Fantastic Voyage, produced by Saul David and directed by Richard Fleischer, was a technically innovative and anatomically accurate story about the treatment of an injured scientist with knowledge critical to the maintenance of world peace and security. Injured in an attack by hostile forces, the scientist could not share this knowledge with the forces of good. The intracranial haematoma causing his coma was located in such a precarious position that surgery to remove it was thought likely to lead to his death and endanger the free world. Scientists and physicians proposed a unique strategy to save the victim: miniaturise a nuclear powered submarine so that it and its crew, including
Anomalous synthesis of ppGpp in growing cells.

Abstract In E. coli cells, accumulation of ppGpp is normally triggered by conditions that restrict the aminoacylation of tRNA or interfere with carbon/energy source metabolism; in both cases, the nucleotide's accumulation is associated with control of stable RNA synthesis and is generally believed to bring it about. We have found an anomalous situation wherein vigorously growing cells accumulate a high level of ppGpp and there is no restriction of stable RNA synthesis. This occurs when wild-type cells are shifted up from an abnormally low growth temperature to one in the optimal range (35°C–40°C). The effect is partly, but not entirely, dependent upon the presence of a functional rel A gene product. These results appear to call into question the simpler interpretations of the role of ppGpp in the control of stable RNA synthesis.
Uniformly valid amplitude expansions for non-Abelian gauge theories

The imposition of a particular gauge condition in a non-Abelian gauge theory may lead to large-r nonuniformities in an amplitude expansion when used in the construction of an approximate solution of the field equations of the theory. We show that for both the Yang-Mills theory and general relativity it is always possible to find a class of gauge conditions that do not suffer from this defect and at the same time lead to solvable equations in each order of the approximation employed. We further show how one can construct such gauge conditions by a method similar to Lighthill's method of strained coordinates. An example of such a construction is given for the Yang-Mills theory.
Reply to Y.-T. Lan et al

We appreciate the thoughtful comments of Lan et al from Taiwan. We are pleased that they feel the Surveillance, Epidemiology, and End Results (SEER) outcomes data for 130,762 patients with colon cancer provide powerful evidence to support the revised staging system for colorectal cancer in the seventh edition of the American Joint Committee on Cancer (AJCC) Cancer Staging Manual. The letter by Lan et al centers on the finding that a small percentage of patients with Tis colon cancers in the SEER analysis had involved lymph nodes (114 TisN lesions in 5,935 patients with TisN0-N lesions or 1.9%). Lan et al mention the widely held concept that lymphatic vessels are not found in the mucosal layer and therefore lymph node metastases should not occur but note recent immunohistochemical data showing the presence of lymphatic channels extending to colonic mucosa in neoplastic and inflammatory conditions. In Lan’s institution, involved nodes were found in only one of 118 patients with Tis lesions who had a regional resection, and on pathologic review, the lesion was in fact T2N , not TisN , based on extension of the primary lesion into the superficial muscularis propria. Accordingly, Lan et al suggest that slides of all TisN patients in the SEER colon analysis should be re-reviewed, if possible, to be certain they were limited to the mucosa. Given the possibility of involved nodes in patients with intramucosal colorectal cancers, Lan et al also note that for patients with presumed Tis lesions, further investigation is warranted to define the high-risk group before considering local treatment options such as endoscopic mucosal or submucosal resection. Although we did not comment on patients with Tis lesions in our article, we agree with Lan et al that the finding of involved nodes in patients with intramucosal colorectal cancers (Tis) is both unexpected and uncommon (1.9% in SEER colon analysis and 2.1% in SEER rectal analysis [75 TisN lesions in 3,614 patients with TisN0-N rectal cancer). Even though it would be of interest to review the slides of all patients with TisN lesions in the SEER colon and rectal analyses, unfortunately we cannot attempt such. Many of the blocks are now unavailable for study, so a review of available material would be unavoidably biased. Given the extremely low risk of nodal involvement in patients with Tis lesions, it is reasonable to consider local treatment options in such patients, unless high-risk pathologic findings are identified when the lesion is biopsied.
Alternative approaches to deindividuation.

There have been two different approaches to deindividuation research and theory. One approach has been to view deindividuation as a loss of restraints, afforded by anonymity and other forms of depersonalization. Theorists adopting this perspective, which has its origins in crowd theory, view the experience of deindividuation as a positively affective event. Theorists adopting the other view predict that deindividuation arouses negative affect and serves as a stimulus for behavior that establishes the uniqueness and continuity of a person's self-conceptions. Research testing each approach is reviewed, and areas for possible integration are posited.
Significance of skeletal muscle oxidative enzyme enhancement with endurance training

A theoretical model is proposed to explain how the increase in mitochondrial protein concentration, and therefore of the oxidative enzymes, that occurs with endurance training could operate to alter the choice of substrate during submaximal exercise in a manner such that the oxidation of fatty acids increases, glycogen depletion and lactate production are reduced, and work capacity is enhanced. The model is based on the control of enzyme activities both by enzyme and substrate concentrations. The effect of altering enzyme concentration on reaction velocities is presented on the basis of standard Henri-Michaelis-Menten kinetics. It is shown that the reaction velocity at a given substrate concentration is a function of total enzyme concentration. With an increase in total enzyme concentration there is a parallel increase in reaction velocity at the same substrate level. This would have its greatest impact at substrate levels below the Km of the enzyme. It would have an effect of enhancing fatty acid flux through the oxidative pathways while inhibiting the Embden-Meyerhof pathway. The model, as proposed, is consistent with known alterations in metabolism as they occur in man during submaximal exercise following endurance training.
Clinical comparison of resorbable and non‐resorbable barriers for guided periodontal tissue regeneration

Abstract The purpose of this study was to compare the clinical results of guided periodontal tissue regeneration (GPTR) using a resorbable barrier manufactured from a copolymer of polylactic and polyglycolic acids (Resolut® Regenerative Material) with those of non-resorbable e-PTFE barrier (Gore-Tex® Periodontal Material). 12 subjects participated, 6 with similarly paired class II furcations and 6 with 2 similar 2,3-wall periodontal lesions. The resorbable and non-resorbable barriers were randomly assigned to 1 defect in each subject. Non-resorbable barriers were removed in six weeks. Plaque index (PII), gingival index (GI), probing depth (PD), clinical attachment level (CAL) and gingival recession (R) were recorded at baseline, (i.e., immediately prior to surgery) and at 12 months postsurgically. The clinical healing was similar and uneventful in both groups. Intrabony pockets depicted significant changes from baseline (p < 0.05) for probing depth reduction and gain in clinical attachment levels. No differences were found between treatments. Class II furcations showed significant improvements from baseline (p < 0.05) for probing depth reduction and clinical attachment gain. No differences were detected between treatments. It is concluded that the resorbable barrier tested is as effective as the nonresorbable e-PTFE barrier for the treatment of class II furcations and intrabony defects.
Histochemical characterization of the interphotoreceptor matrix in the retina of Octopus bimaculoides

Proteoglycans, located in the interphotoreceptor matrix (IPM) of vertebrate retinas, mediate interactions between the photoreceptors and retinal pigment epithelium. Molluscan retinas also have an IPM located between apposing rhabdomeres. Like the cone matrix sheath of the vertebrate IPM, the octopus IPM is labeled by peanut agglutinin (PNA) and contains retinoid-binding-like proteins. In this study we demonstrate further similarities of the vertebrate/invertebrate IPM and identify specific molecular components in this extracellular compartment of the octopus retina. For light microscopy, paraffin-embedded sections of octopus retinas were stained with dyes specific for acid mucopolysacharides including Alcian blue and colloidal iron. In addition, sections were digested with enzymes specific for hyaluronan, chondroitin sulfate, and sialoglycoconjugates. Digestion of sections with these enzymes and subsequent staining with Alcian blue or colloidal iron demonstrated the presence of chondroitin sulfate and sialoglycoconjugates in the octopus IPM as well as other retinal layers and cells. At the electron-microscope level we treated retinal tissue with Cuprolinic Blue and observed the distribution of sulfated glycosaminoglycans along the rhabdomere edges facing the IPM and in a more central area of the IPM where microvillous processes of supportive cells are located. The octopus IPM may have importance in retinal structure and may be a scaffolding on which molecular components of the IPM are located.
Antigenic relationships between an isolate of the Western Subtype of tick-borne encephalitis virus and an inactivated vaccine derived from it.

High mutation rates resulting from the error prone replicases of RNA viruses could lead to antigenic alterations in viral products and pose significant problems during the manufacture of vaccines against RNA viruses. The production of a vaccine against tick-borne encephalitis virus has been monitored using both polyclonal sera and a library of monoclonal antibodies. Only a few antigenic changes were detected during the alteration of host cell from mouse brain to avian fibroblasts and upon subsequent expansion of the virus population during several rounds of replication. In addition, when the formalin inactivation process was monitored for antigenic change, virtually none was detected
Use Of A Confocal Scanning Laser Microscope For The Measurement Of Submicrometer Critical Dimensions

Although scanning electron microscopes (SEM) are usually used for measuring submicrometer critical dimensions (CD), the shortcomings of using an SEM for this purpose have prompted an investigation of the use of a new alternative, the confocal scanning laser microscope (CSLM). A SiScan-I instrument manufactured by SiScan Systems was used in this study. The most attractive features of a CSLM are its reliability, ease of use, and high precision. CDs as small as 0.5 pm can be measured on most samples with an instrumental precision of about 0.03μm (3 σ ). However, variable systematic errors may reduce the practical precision of the instrument if certain parameters are not tightly controlled from sample to sample. Results are presented that show how CD measurements are affected by the following key parameters: 1) thickness of the resist, 2) thickness of an underlying transparent layer, 3) size of the feature, and 4) slope of the edge wall of the resist. Although all of these parameters are found to affect the CSLM measurements, errors due to variations in parameters 1, 3, and 4 will probably be insignificant for a well controlled lithographig process.. Variations in parameter 2 are often less well controlled and systematic CD errors on the order of 100 to 200 A per 100 A of variation in the film thickness can be expected. Suggestions are made whereby operators can recognize and compensate for these types of systematic errors. It appears that CDs of most samples can be measured on a CSLM with an effective precision of about 0.05 μm (3σ ), which is comparable to that of an SEM based measuring system. This precision estimate includes 0.03 μm for random instrumental errors and up to 0.04 μm for systematic errors due to random variations in the sample.
Cross-linking of Selected Residues in the N- and C-terminal Domains of Escherichia coli Protein L7/L12 to Other Ribosomal Proteins and the Effect of Elongation Factor Tu

Five different variants of protein L7/L12, each with a single cysteine substitution at a selected site, were produced, modified with125I-N-[4-(p-azidosalicylamido)-butyl]-3-(2′-pyridyldithio)propionamide, a radiolabeled, sulfhydryl-specific, heterobifunctional, cleavable photocross-linking reagent that transfers radiolabel to the target molecule upon reduction of the disulfide bond. The proteins were reconstituted with core particles depleted of wild type L7/L12 to yield 70 S ribosomes. Cross-linked molecules were identified and quantified by the radiolabel. No cross-linking of RNA was detected. Two sites in the dimeric N-terminal domain, Cys-12 and Cys-33, cross-linked strongly to L10 and in lower yield to L11 but to no other proteins. The three sites in the globular C-terminal domain all cross-linked strongly to L11 and, in lower yield, to L10. Weaker cross-linking to 50 S proteins L2 and L5 occurred from all three C-terminal domain locations. The 30 S ribosomal proteins S2, S3, S7, S14, S18 were also cross-linked from all three of these sites. Binding of the ternary complex [14C]Phe-tRNA·elongation factor Tu·guanyl-5′-yl imidodiphosphate) but not [14C]Phe-tRNA·elongation factor Tu·GDP·kirromycin increased labeling of L2, L5, and all of the 30 S proteins. These results imply the flexibility of L7/L12 and the transient proximity of three surfaces of the C-terminal domain with the base of the stalk, the peptidyl transferase domain, and the head of the 30 S subunit.
Compartmental neck fat accumulation and its relation to cardiovascular risk and metabolic syndrome

BACKGROUND Neck circumference is a predictor of cardiovascular disease (CVD) risk. However, detailed assessment of neck fat has not been explored, and the contribution from individual neck fat compartments to CVD risk is unknown. OBJECTIVE The objective was to measure neck adipose tissue (NAT) compartments and examine relations with CVD risk markers, with the hypothesis that neck adipose tissue (NAT) accumulation preferentially involves specific compartments that contribute differently to metabolic risk. DESIGN We retrospectively studied 303 subjects with successfully treated malignancies or benign etiologies [151 women, 152 men; mean (± SD) age: 55 ± 17 y; mean body mass index (BMI; in kg/m(2)): 28 ± 6] who underwent whole-body positron emission tomography/computed tomography. NAT was measured at the level of the C5 vertebral body, subdivided into posterior (NATpost), subcutaneous (NATsc), and perivertebral (NATperivert) compartments. Data on CVD risk factors (BMI, abdominal circumference, visceral and abdominal subcutaneous adipose tissue, blood pressure, serum lipids, and fasting plasma glucose) were collected. We compared NAT compartments across lean, overweight, and obese groups and performed multivariate regression models correlating NAT with CVD risk factors. Receiver operating characteristic curve and prevalence ratio analyses were performed to examine the association of NAT compartments with metabolic syndrome. RESULTS NATpost and NATsc were more consistently associated with cardiometabolic risk, especially in women, correlating with visceral adipose tissue (P < 0.0001) and triglycerides (P < 0.001) and a nearly 1.5-fold increase in the prevalence ratio for metabolic syndrome after adjustment for age and BMI (P < 0.05). NATsc was most abundant in women, whereas intermuscular compartments (NATpost and NATperivert) were higher in men. In both sexes, NATpost and NATperivert showed the largest increment between lean and obese subjects. CONCLUSIONS Neck fat compartments expand differently with increasing adiposity, correlate with CVD risk factors, and are associated with metabolic syndrome, most notably NATpost and NATsc in women. Although neck circumference remains an important method to assess metabolic risk, cross-sectional NAT assessment provides further insight into fat accumulation in the neck. This trial was registered at clinicaltrials.gov as NCT02205021.
Superconductivity and Intralayer Structure in Potassium Amalgam-Gic

We report on the structural, lattice and electronic properties of stage 1,2,3 potassium-amalgam GIG and the relation of these properties to the observed superconducting transition temperature. The ultramicrostructure of the intercalant domains is investigated using lattice fringe imaging. Our observation of macroscopic (√3×√3),(2×2) and (√3×2) domains is consistent with the basal plane zonefolded phenomena observed in the Raman spectra. Shubnikovde Haas measurements of the Fermi surface show high frequency (>1000 T) oscillations in stage 2, identified with the intercalant band.
Growth in infants with congenital adrenal hyperplasia due to 21-hydroxylase deficiency: An analysis of the factors affecting height

Abstract Background It has been suggested that overtreatment of infants with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency might affect their growth and final height. Objective To assess the axiological parameters of infants with CAH due to 21-hydroxylase deficiency from their first presentation in neonatal period and during infancy, in an attempt to decide the optimum doses of glucocorticoid, mineralocorticoid and salt therapy that can achieve androgen suppression, prevent life-threatening salt-wasting crises, and allow normal growth velocity for age. Materials and methods Retrospective study conducted in the Diabetes Endocrine and Metabolism Pediatric Unit at Children’s Hospital, Cairo University included baseline and follow-up data of 28 infants with 21-hydroxylase deficiency. Results Median age at presentation was 34 days. Lower doses of hydrocortisone ( Conclusion Poor growth in infants with salt wasting CAH was not related to age at diagnosis and start of therapy, doses of glucocorticoid, fludrocortisones, or saline therapy. Male sex and mean basal length SDS below −2 were associated with a more favorable growth catch up. Further prospective studies with inclusion of intercurrent illnesses and nutritional status are needed.
Glycosyl-inositol deivatives II. Synthesis of 2-amino-2-deoxy- galactosyl-α-1,3---inositol

Abstract The “azide method” has been applied to the preparation of a 2-amino-2-deoxy-α- D -galactosyl- D - chiro -inositol disaccharide, using silver perchlorate and silver carbonate as the coupling reaction catalysts.
The efficacy of several irrigating solutions for endodontics: a scanning electron microscopic study.

The perforated irrigation needle was used to test a high-volume (20 c.c.) final flush of prepared root canals. Three solutions: TEGO 1 percent, NaOCl 5.25 percent, and REDTA were tested. The roots were split longitudinally and were prepared for examination under the scanning electron microscope immediately after preparation and final flushing. In addition, groups were prepared and flushed in the same manner, but after splitting they were soaked in the respective solutions for 3 hours and then examined. The results indicated that the smeared layer is caused by instrumentation, that it is not removed by TEGO or NaOCl, and that it is removed by REDTA. It may be that the smeared layer is a slurry of dentin filings, since REDTA does not remove soft tissue. All solutions produced a canal quite free of debris; however, none of the tested irrigants was completely satisfactory by itself.
Non-adiabatic and ultrafast dynamics of hydrogen adsorbed on silicon

Abstract Light stimulated reactions, and the closely related electron stimulated reactions, form the basis of all lithographic techniques currently used and under commercial development for the production of integrated circuits (ICs) and microelectromechanical systems (MEMS). A long-standing goal is to understand how radiation is converted into excited electrons and how these electrons exchange their energy with substrate atoms and atoms bound to the surface of the substrate. The lifetime of such excited states is of order 1 × 10 −15 s (1 fs). The electrons exchange energy with the lattice of the solid in the sub-picosecond ( −12 s) range. Therefore, to probe these excitations, one is compelled to use pulsed lasers with a pulse duration in the femtosecond range. Such lasers are capable of extremely high peak powers and non-linear phenomena can feature prominently in the photochemistry initiated by them. This, in turn, leads to reaction dynamics that differ markedly from the dynamics that rule linear photochemistry. Great strides have been made in the ability of theory to model and explain surface chemistry on metals. The theoretical description of semiconductor surfaces remains challenging, though progress is steady. An even greater challenge is the calculation of excited states and the associated non-adiabatic processes, though such calculations are becoming an increasingly active area of research. This review treats ultrafast energy relaxation and the dynamics of desorption induced by non-adiabatic excitations. Photon and electron stimulated as well as scanning probed tip induced processes are discussed.
A Chemically Functionalized Carboxylate−Alumoxane Nanoparticle Support for Olefin Polymerization Catalysts

A metallocene/MAO-based solid olefin polymerization catalyst has been developed using chemically functionalized nanoparticles (carboxylate-alumoxanes) as a well-defined substrate. Reaction of p-hydroxybenzoate-alumoxane (p-HB-A) nanoparticles, formed from the acid with boehmite, with methylalumoxane (MAO) results in a solid nanoparticle-based MAO (n-MAO), which in combination with zirconocenes [including Cp 2 ZrCl 2 , Cp 2 ZrMe 2 , and ( n BuCp) 2 ZrCl 2 ] produces an active solid catalyst for olefin polymerization. The catalytic activity of the n-MAO-based catalyst is comparable to the homogeneous analogue and a traditional silica-supported catalyst under identical reaction conditions and with the same Al (MAO) :Zr ratio. The n-MAO approach offers the potential of the MAO being easily chemically modified.
Listening to your inner voices: investigating means for voice notifications

Our research investigates notification qualities of different types of voices, moving toward interfaces that support optimal allocation of attention to maximize system utility. We conducted an experiment to determine the interruption, reaction, and comprehension values of three different voice categories: the user's voice, a familiar voice, and an unfamiliar voice. Initial testing showed significant and impactful results: unfamiliar voices are the least interruptive, and a user reacts most quickly to one's own voice. Motivated by these findings, we report on the development and deployment of a notification system that exploits the differences in familiarity of a voice.
Clinical experience with paraspinal mapping. II: A simplified technique that eliminates three-fourths of needle insertions

Abstract Objective: To simplify and minimize the quantified needle examination of the paraspinal muscles (paraspinal mapping [PM]) without compromising sensitivity or specificity. Design: Nonrandomized prospective trial. Setting: Electrodiagnostic laboratory of a university spine center and of a private practice in a small community. Subjects: One hundred fourteen consecutive persons referred for electrodiagnosis of spinal or lower extremity disorders who had PM data and 35 previously reported asymptomatic volunteers. Intervention: Abbreviated PM protocols were simulated by progressively eliminating data from the 45 needle insertions of the original PM. Simulations involving 35, 15, 13, and 5 insertions resulted in different normal values (95% of asymptomatic volunteers) and different scores in patients. The resulting reclassification of patients as normal or abnormal was compared with the original protocol and with clinical data. Main Outcome Measures: False positive and false negative rates of the simulations compared with the original protocol. Results: Abbreviated protocols involving 30, 15, 13, and 5 needle insertions had normal cutoff scores of less than 5, less than 4, less than 3, and less than 2, respectively, with 2%, 2%, 4%, and 8% false positive rates and 3%, 8%, 13%, and 21% false negative rates compared with the original. In many cases clinical information correlated better with the abbreviated test results than the original PM. Conclusions: The third protocol compared well with the original PM, and in a limited number of patients with imaging studies demonstrated 92% sensitivity and 92% specificity. By eliminating the iliocostalis, longissimus, and lowest multifidus needle explorations, 73% fewer needle insertions were used. We recommend that this new technique, now called "miniPM," be used in most clinical settings.
Structural and magnetic properties of R2Fe17-xBex compounds with R = Y, Pr, Nd, Sm, Gd, Tb and Dy

The effect of partial Fe substitution by Be on structure and magnetic properties has been studied across the R2Fe17-xBex series, where R = Y, Pr, Nd, Sm, Gd, Tb and Dy. On Be substitution, the Th2Zn17 type rhombohedral structure is stabilized across the series, even for R = Dy and Tb which stabilize in the Th2Ni17 type hexagonal structure without Be substitution. Depending on the R element, one or more Be atoms (up to five) per formula unit can be retained in the Th2Zn17 type structure. The lattice parameters, magnetic ordering temperature and saturation magnetic moment decrease upon Be substitution. The easy magnetization direction of the samples with a higher magnetic ordering temperature is still within the basal c plane. The variation of magnetic properties is discussed in correlation with volume effects, dilution effects and electron hybridization.
Problem of fermion generations in grand unified theories

We investigate the problem of incorporating the fermion generations within the framework of a grand unified $\mathrm{SU}(N)$ gauge theory. The requirement of no triangle anomaly and an asymptotically free gauge coupling constant appears to limit the number of light-fermion generations to four. Specializing to an SU(8) model, we exhibit a Higgs mechanism that splits the fermions into heavy and light sets, the latter containing only three generations. We argue that the mass of the heavy generation is in the TeV region.
Ranked set sampling, coherent rankings and size-biased permutations

Abstract The paper examines the effect of the set size upon the performance (reciprocal variance) of balanced ranked set sampling for estimation of a population mean. Performance is shown to be monotone increasing with the set size for the wide class of ranking models that satisfy a property called coherence. This class includes perfect ranking as well as ranking by concomitant variable. Stochastic ranking models based upon size-biased permutations are also shown to satisfy coherence and, consequently, monotonicity.
Longitudinal, intermodality registration of quantitative breast PET and MRI data acquired before and during neoadjuvant chemotherapy: preliminary results.

Purpose: The authors propose a method whereby serially acquired DCE-MRI, DW-MRI, and FDG-PET breast data sets can be spatially and temporally coregistered to enable the comparison of changes in parameter maps at the voxel level. Methods: First, the authors aligned the PET and MR images at each time point rigidly and nonrigidly. To register the MR images longitudinally, the authors extended a nonrigid registration algorithm by including a tumor volume-preserving constraint in the cost function. After the PET images were aligned to the MR images at each time point, the authors then used the transformation obtained from the longitudinal registration of the MRI volumes to register the PET images longitudinally. The authors tested this approach on ten breast cancer patients by calculating a modified Dice similarity of tumor size between the PET and MR images as well as the bending energy and changes in the tumor volume after the application of the registration algorithm. Results: The median of the modified Dice in the registered PET and DCE-MRI data was 0.92. For the longitudinal registration, the median tumor volume change was −0.03% for the constrained algorithm, compared to −32.16% for the unconstrained registration algorithms (p = 8 × 10−6). The medians of the bending energy were 0.0092 and 0.0001 for the unconstrained and constrained algorithms, respectively (p = 2.84 × 10−7). Conclusions: The results indicate that the proposed method can accurately spatially align DCE-MRI, DW-MRI, and FDG-PET breast images acquired at different time points during therapy while preventing the tumor from being substantially distorted or compressed.
Zoogeomorphology: Animals as Geomorphic Agents

Acknowledgements 1. Introduction 2. The geomorphic influences of invertebrates 3. The geomorphic accomplishments of ectothermic vertebrates 4. Birds as agents of erosion, transportation and deposition 5. The geomorphic effects of digging for and caching food 6. Trampling, wallowing and geophagy by mammals 7. The geomorphic effects of mammalian burrowing 8. The geomorphic influence of beavers 9. Concluding remarks References Index.
The application and use of chemical space mapping to interpret crystallization screening results

Macromolecular crystallization screening is an empirical process. It often begins by setting up experiments with a number of chemically diverse cocktails designed to sample chemical space known to promote crystallization. Where a potential crystal is seen a refined screen is set up, optimizing around that condition. By using an incomplete factorial sampling of chemical space to formulate the cocktails and presenting the results graphically, it is possible to readily identify trends relevant to crystallization, coarsely sample the phase diagram and help guide the optimization process. In this paper, chemical space mapping is applied to both single macromolecules and to a diverse set of macromolecules in order to illustrate how visual information is more readily understood and assimilated than the same information presented textually.
Simultaneous use of non-medical ADHD prescription stimulants and alcohol among undergraduate students.

Background Use of prescription stimulants used to treat Attention Deficit/Hyperactivity Disorder (ADHD) for reasons other than prescribed, known as non-medical use, is a growing problem among undergraduates. Previous studies show that non-medical prescription stimulant (NMPS) users consume more alcohol than individuals who do not use NMPS. However, research on simultaneous use of NMPS and alcohol is limited. The objectives of this study were to: (1) determine the prevalence of simultaneous use of alcohol and NMPS; (2) examine predictors and consequences of simultaneous NMPS and alcohol use among undergraduates.
917-93 Myocardial Fatty Acid Oxidation: Saturated Versus Unsaturated

Fatty acid (FA) metabolism is an integral part of myocardial cellular metabolism and has been studied in normal, ischemic, post-ischemic, and hibernating myocardium with Positron Emission Tomography and carbon-14 methods. These tracer studies generally follow only the saturated (S) FA, palmitate. Human plasma contains a mixture of unsaturated (unS) and SFAs in a 1.3: 1 ratio. It remains unclear if the oxidation of palmitate is representative of a biological mixture of FAs. The purpose of this study was to determine if oxidation of SFAs or unSFAs is similar to a biological mixture. Methods Working rat hearts were supplied with carbon-13 enriched lactate (8 mM) in addition to FA (0.27 mM) as either SFA, unSFA or a biological mixture. The FAs studied (palmitic[16:0], palmitoleic[16:1]. stearic[18:0], OIeic[18:1]. Iinoleic[18:2]) constitute g 85% of the FAs found in plasma. The mixture consisted of all 5 FAs in their relative proportions in human plasma. Carbon-13 Magnetic Resonance Spectroscopy and isotopomer analysis were used to determine the contribution of each substrate to the acetylCoA pool. The results were analyzed using ANOVA and Student-NewmanKeuls tests. Results The type of FA used did not significantly alter CO or RPP. The oxidation of unSFAs was significantly less than the oxidation of SFAs or the biological mixture of FAs. Fatty acid n FA utilization(%) CO (ml/min) Rpp (mmHg × beats/min) Mixture 4 64 ± 4 45 ± 10 29 ± 5 Saturated 8 55 ± 7 42 ± 1.3 28 ± 5 Unsaturated 12 35 ± 10 * 46 ± 12 28 ± 5 * p l 0.05 Conclusions Under these conditions saturated FAs are preferred for oxidation compared to unsaturated FAs. The oxidation of palmitate or stearate appears representative of a biological mixture.
Design and evaluation of a method for admission control for broadband packet networks

Abstract In this paper two admission control algorithms are defined and evaluated. The algorithms are designed for use with an architecture which segregates traffic flows into multiple queues, one for each individual connection or one for each class of connections. The approach makes it possible to provide multiple classes of service. Resource allocation tables can be prepared efficiently, using simulation. The resulting tables are independent of possible traffic mixtures and require only two scalar numbers to specify required resources. The admission process can be carried out by passing the two numbers between nodes, and it is not necessary to provide detailed information about traffic mixtures. The paper presents a comprehensive performance study, carried out with simulation, to evaluate the performance of the proposed admission control algorithms in relation to other algorithms described in the literature. Under the conditions used in the performance study, simulation is used to establish an admissible region of all possible combinations of the numbers of sources in two classes of traffic which can be supported by a specific channel independent of the admission algorithm. Thus, the algorithms are compared to the best that is possible as well as competing algorithms. For the case of multiple sources with different quality of service requirements, one of the proposed algorithms outperformed three competing algorithms and gave results close to the best that can be achieved with any admission algorithm.
Moving with the flow: what transport laws reveal about cell division and expansion

This material was presented as a keynote talk for the symposium, "Crosstalk between cell division and expansion," organized by G.T.S. Beemster and H. Tsukaya at the International Botanical Congress, Vienna in July, 2005. The review focuses on the utility of continuity equations to understand relationships among cell size, division and expansion; insights from Lagrangian or cell-specific descriptions of developmental variables; and a growth-diffusion equation to show effects of root growth zones on the surrounding soil.
WE-B-220-02: Advances in MR for Guidance of US Therapy

Image guidance of focused ultrasound therapy is important for targeting the therapy, ensuring treatment and safety, and for assessing the therapy. This presentation will describe recent advances in these areas of the MR guidance of focused ultrasound. Accurate focusing of the ultrasound beam to the target tissue can be done with a low temperature rise “test shot.” Alternatively, imaging the acoustic radiation force allows visualization of the focal spot without a temperature rise. MR imaging of the acoustic radiation force displacement (MR‐ARFI) relies on the application of the ultrasound during a portion of a series of gradient lobes. In areas where the tissue is displaced, the water spins experience a different magnetic field and accumulate phase, which is not fully refocused at the time of signal measurement. The visualization of the focal spot can thus be achieved without a temperature rise. In addition to straightforward visualization of the focal spot, MR‐ARFI can provide a means for image feedback when correcting phase aberrations from the skull. An iterative method allows modification of transducer phases while maximizing the displacement at the focus. A non‐iterative method requires the MR‐ARFI measurements to be made, followed by a matrix inversion. For tissue ablation, MR thermometry can be used to accurately monitor tissue temperature. MR thermometry can be very sensitive to motion, including motion of the treated tissue or even motion of tissue in the vicinity of the treated tissue (such as due to respiration). Temperatureimaging methods must be robust to these types of motions and solutions include multibaseline, referenceless, and hybrid multibaseline/referenceless approaches. Another important task for MR guidance is in beam steering in moving organs, such as the liver and kidneys.This can be done based on imaging alone or on a combination of imaging and respiratory phase monitoring, such as can be done with the bellows. Lastly, there are a number of methods under investigation for the visualization of ablated tissue. MR‐ARFI is a potential candidate. The acoustic radiation force displacement depends both on the ultrasound intensity and on the displacement of the tissue, which in the latter case ARFI relies on tissue displacement by the ultrasound beam, which is related to the tissue stiffness. Evaluating the change in tissue stiffness provides the spatial extent of the thermal ablation. Other evaluative imaging methods includes contrast enhanced MRI, which visualizes disruption of perfusion, and diffusion‐weighted MRI, which demonstrates a 36% decrease in ADC in the ablated tissue. Learning Objectives 1. Understand the basis for acoustic radiation force imaging and its applications 2. Understand the current research in the image guidance of focused ultrasound
Nitric oxide regulates BDNF release from nodose ganglion neurons in a pattern-dependent and cGMP-independent manner

Activity of arterial baroreceptors is modulated by neurohumoral factors, including nitric oxide (NO), released from endothelial cells. Baroreceptor reflex responses can also be modulated by NO signaling in the brainstem nucleus tractus solitarius (NTS), the primary central target of cardiovascular afferents. Our recent studies indicate that brain-derived neurotrophic factor (BDNF) is abundantly expressed by developing and adult baroreceptor afferents in vivo, and released from cultured nodose ganglion (NG) neurons by patterns of baroreceptor activity. Using electrical field stimulation and ELISA in situ, we show that exogenous NO nearly abolishes BDNF release from newborn rat NG neurons in vitro stimulated with single pulses delivered at 6 Hz, but not 2-pulse bursts delivered at the same 6-Hz frequency, that corresponds to a rat heart rate. Application of L-NAME, a specific inhibitor of endogenous NO synthases, does not have any significant effect on activity-dependent BDNF release, but leads to upregulation of BDNF expression in an activity-dependent manner. The latter effect suggests a novel mechanism of homeostatic regulation of activity-dependent BDNF expression with endogenous NO as a key player. The exogenous NO-mediated effect does not involve the cGMP-protein kinase G (PKG) pathway, but is largely inhibited by N-ethylmaleimide and TEMPOL that are known to prevent S-nitrosylation. Together, our current data identify previously unknown mechanisms regulating BDNF availability, and point to NO as a likely regulator of BDNF at baroafferent synapses in the NTS.
Organic/Fluorous Phase Extraction: A New Tool for the Isolation of Organometallic Complexes

Strategies for isolating and purifying organometallic complexes are limited. The use of the unique solubility properties of fluorous reagents allows for purification by fluorous/organic phase extraction. An 85% yield of pure (Rfh)3SnCp* (1, Rfh = (CH2)2(CF2)5CF3) was isolated by filtration and extraction with FC-72 (fluorinated hexanes) of the reaction of (Rfh)3SnBr with Cp*Li. The reaction of 1 with TaCl5 and NbCl5 gave the alkylated products Cp*TaCl4 and Cp*NbCl4, respectively. These products were isolated from the reaction mixtures in good yields by simple extraction with a biphasic combination of FC-72 and a nonfluorinated solvent.
Time and process of sperm penetration into cumulus‐free mouse eggs fertilized in vitro

Sperm penetration through the zona pellucida and fusion of the sperm head with the vitellus were observed continuously and filmed under phase optics in cumulus-free living mouse eggs inseminated in vitro with capacitated epididymal sperm. Most spermatozoa penetrated the zona pellucida, traversed the perivitelline space, and fused with the vitellus at an angle nearly perpendicular to the surface. The mean duration required for sperm to penetrate the zona pellucida was 20 minutes with a range of 15–26 minutes. Sperm traversed the perivitelline space in less than one second. The initial contact of sperm with the vitellus generally took place at the tip of the sperm head. When the tip of the sperm head contacted the vitellus there was an immediate reduction in the rate of flagellation, followed by the gradual sinking of the sperm head into the vitellus.
Factors Influencing the Relationship Between Sexual Trauma and Risky Sexual Behavior in College Students

While the relationship between sexual trauma and risky sexual behavior (RSB) has received much attention, only a handful of studies have investigated the factors that protect victims of sexual trauma from developing this maladaptive pattern of behavior. The current study investigated the protective role of social support, quality and quantity, in developing RSB, through the mechanism of problematic substance use. Two hundred and seventy-five female college students completed a series of self-reports assessing sexual trauma, problematic substance use, social support quality and quantity, and RSB. The results indicated a positive relationship between sexual trauma severity and RSB. Further, this relationship was mediated by participants’ problematic substance use. Social support quality acted as a buffer against the relationship described above where quantity exacerbated this relationship. Implications will be discussed.
Acetylcholine Receptor-Based Biosensor

Abstract The acetylcholine (ACh) receptor protein isolated from Torpedo electric organ was incorporated into asolectin liposomes and immobilized noncovalently on the surface of a Planar Interdigitated Capacitive sensor to produce an ACh receptor-based biosensor. Capacitance of the biosensor, which was stable in buffered saline, increased rapidly when ACh was added. The response was dosedependent and specific for ACh, and the biosensor did not respond to six other neurotransmitters. Impure receptor preparations containing ACh esterase produced a smaller signal in response to ACh but showed enhanced response after inhibition of ACh esterase with diisopropylfluorophosphate. The competitive antagonist d-tubocurare, and the noncompetitive antagonist amantadine, inhibited the response of the biosensor to ACh, but a time-dependent recovery occurred upon perfusion with ACh. The irreversible antagonist α-neurotoxin inhibited the response and there was no recovery following perfusion with ACh. Thus, the pharmacolog...