cssi/SciSciGPT-SciSciNet huggingface dataset:
Learning noisy characters, multiplication codes, and cryptographic hardcore predicates

We present results in cryptography, coding theory and sublinear algorithms. In cryptography, we introduce a unifying framework for proving that a Boolean predicate is hardcore for a one-way function and apply it to a broad family of functions and predicates, showing new hardcore predicates for well known one-way function candidates such as RSA and discrete-log as well as reproving old results in an entirely different way. Our proof framework extends the list-decoding method of Goldreich and Levin [40] for showing hardcore predicates, by introducing a new class of error correcting codes and new list-decoding algorithm we develop for these codes. In coding theory, we introduce a novel class of error correcting codes that we name: Multiplication codes (MPC). We develop decoding algorithms for MPC codes, showing they achieve desirable combinatorial and algorithmic properties, including: (1) binary MPC of constant distance and exponential encoding length for which we provide efficient local list decoding and local self correcting algorithms; (2) binary MPC of constant distance and polynomial encoding length for which we provide efficient decoding algorithm in random noise models; (3) binary MPC of constant rate and distance for which we provide (non polynomial time) decoding algorithm in adversarial noise model. MPC codes are unique in particular in achieving properties as above while having a large group as their underlying algebraic structure. In sublinear algorithms, we present the SFT algorithm for finding the sparse Fourier approximation of complex multi-dimensional signals in time logarithmic in the signal length. We also present additional algorithms for related settings, differing in the model by which the input signal is given, in the considered approximation measure, and in the class of addressed signals. The sublinear algorithms we present are central components in achieving our results in cryptography and coding theory. Reaching beyond theoretical computer science, we suggest employing our algorithms as tools for performance enhancement in data intensive applications, in particular, we suggest replacing the O(N log N)-time FFT algorithm with our Qd (log N)-time SFT algorithm for settings where a sparse approximation suffices. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)
Electromigration in Cu Thin Films

Cu wiring in integrated circuits for high-performance chips has been pursued for many years[1, 2, 3, 4]. The production of IC chips with Cu interconnections has increased each and every year since its initial commercialization in 1997 by DBM.[5] Chips with Cu wiring have improved conductivity, which has resulted in reduced RC time delays for wiring, where R is resistance and C is capacitance. When IC chip technology is extended below 0.2-μm dimension, the RC delays from interconnections will constitute a large percentage of the total chip time delay.[5] In addition to reduced resistance, Cu interconnections have longer electromigration lifetimes compared to chips with the conventional Al(Cu) metallization.[5, 6, 7, 8, 9, 10, 11, 12, 13] Electromigration arises from the motion of atoms under the influence of intense electric field and current. The imbalance of atomic flux at some critical sites in metal lines results in the formation of voids or extrusions, resulting in failure of the chips. Electromigration in Al(Cu) thin films has been a subject of extensive studies for several decades.[14, 15, 16] Investigators have reported that electromigration in Al thin-film lines is related to grain boundary diffusion,[16] interface diffusion between Al and TiN,[17] TiAl3,[17,18] A10x,[19] crystallographic texture,[20, 21] solute (Cu) effects,[22,23] and, to a lesser extent, bulk diffusion[24].
5-Fluorouracil-radiation interactions in human colon adenocarcinoma cells.

The purpose of this investigation was to determine the effect of cellular proliferation and cell cycle stage on the ability of postirradiation 5-fluorouracil (5-FU) to radiosensitize cultured human colon adenocarcinoma Clone A cells. Cell survival curves were generated for irradiated: (a) log- and plateau-phase Clone A cells; and (b) Clone A cells separated by centrifugal elutriation into the various phases of the cell cycle; with and without postirradiation treatment with 100 {mu}g/ml 5-FU. Postirradiation treatment with 5-FU sensitized proliferating cells to a greater degree than it sensitized cells growing in plateau phase. The {beta} component of cell kill in log-phase cells was increased by a factor of 1.5 with a sensitizer enhancement ratio of 1.21 at the 0.01 survival level. Plateau-phase cells showed less radiosensitization (sensitizer enhancement ratio of 1.13 at the 0.01 survival level); however, there was a mild increase in both {alpha} and {beta} kill in plateau-phase cells. Elutriated G{sub 1} cells were the most radiosensitive, independent of treatment with 5-FU. The phase of the cell cycle had little effect on the ability of fluorouracil to radiosensitize Clone A cells. Proliferating cells are more susceptible to radiosensitization with 5-FU than plateau-phase cells are, but this effect appears tomore » be independent of the phase of the cell cycle. 18 refs., 4 figs., 3 tabs.« less
Application of the biaxial Iosipescu method to mixed-mode fracture of unidirectional composites

In this paper the biaxial Iosipescu test method has been used, employing specimens with a central precrack placed along the notch-root axis, to study the intralaminar failure properties of a unidirectional carbon/epoxy composite under mixed-mode (dominated by shear) loadings. A linear finite element analysis has been performed to determine the energy release rates and stress intensity factors for the central crack under various biaxial loading conditions. In addition, a series of simple and biaxial fracture experiments have been performed on the composite material. Numerical results indicate that the method is capable of generating a wide range of mixed-mode loading conditions at the crack tip for various loading angles and crack lengths. Using the numerical results, in conjunction with experimental data, the biaxial intralaminar failure process in the cracked Iosipescu specimens has been explained.
Chemical durability of commercial silicate glasses. I. Material characterization

Six commercial silicate glasses; silica, sodalime silicate, two fiberglass compositions and two Bioglass® compositions were subjected to three solutions: distilled water, Dulbecco's phosphate buffered saline solution and Ham's F-12 1x cell culture media under the exact experimental conditions that would be encountered during a cell culture study. For companion, a binary sodium silicate glass was also exposed. Weight loss, diffuse reflectance infrared spectroscopy (DRIFTS) and potentiometric titration were used to determine the chemical evolution of the substrates during a typical period for cell culturing. The silica, sodalime silicate and high-silica fiberglass material showed only small changes in all cases except for differences in OH active site concentration. The bioglass compositions and the low-silica fiberglass exhibited solution-dependent dynamic surface chemistry. The sodium silicate was too dynamic for even the most aggressive buffering system. The purpose of this study was to elucidate cell behavior to be reported in a later paper.
Tip of the Red Giant Branch Distances to Galaxies. IV. Sextans B

We present color-magnitude diagrams and luminosity functions of stellar populations in the nearby dwarf galaxy Sextans B, based on VI photometry acquired with the Carnegie Observatories spectroscopic multislit and imaging camera CCD prime-focus camera on the Palomar 5 m telescope. Combining previously published Cepheid observations with our new data, we obtain a distance to Sextans B based on the multiwavelength period-luminosity (PL) relations; BVRI data for eight Cepheids having periods ranging from 4 to 30 days were used. This Population I true distance modulus for Sextans B is found to be (m - M)0 = 25.69 ± 0.27 mag (1.37 ± 0.18 Mpc) with an extinction value of AV = 0.05 mag. The Cepheid distance is then compared with the Population II distance, determined by applying the tip of the red giant branch (TRGB) method. A discontinuity in the I-band luminosity function is detected at I = 21.60 ± 0.10 mag. Adopting MI = -4.04 ± 0.02 mag as the absolute magnitude of the TRGB, and taking into account the Galactic extinction value of AI = 0.02 mag, we obtain a Population II distance modulus of (m - M)0 = 25.56 ± 0.10 mag (1.29 ± 0.07 Mpc). Additional systematic uncertainties in the TRGB distance scale probably exist at the 5%-10% level. The agreement between the two distances and their uncertainties derived from distinctly independent methods further demonstrates that the accuracy and precision of the TRGB method as an extragalactic distance indicator are comparable to those of the Cepheid PL relation.
New developments in biologics therapy: what about from the medical point of view?

Crohn’s disease (CD) is a disabling chronic inflammatory disease of the bowel that, despite medical treatment, progresses towards complications and surgery. The advent of biologic therapy over the last few years has had a powerful impact on the approach to the management of inflammatory bowel disease, in particular for patients with refractory or steroid-dependent course. The introduction of infliximab, adalimumab and certolizumab pegol into the CD armamentarium has significantly improved the treatment of patients with CD. In the first infliximab induction trial, 108 patients with moderate to severe CD were randomized to receive a single dose of infliximab or placebo. Eighty-one percent of patients administered infliximab (5 mg/kg dose) had a clinical response (reduction of ≥70 points on the CDAI) at week 4 compared with 17% of patients in the placebo arm (P < 0.001). The ACCENT I trial assessed the benefit of maintenance infliximab therapy in 573 patients with moderate to severe CD. Patients who responded (reduction of ≥70 points on the CDAI) to one infliximab (5 mg/kg) infusion by week 2 were randomized to receive placebo or infliximab (5 mg/kg or 10 mg/kg) at weeks 2, 6, and then every 8 weeks through week 46. At week 54, 28% of patients who received infliximab (5 mg/kg) were in remission compared with 15% of patients who received placebo (P = 0.007). The CLASSIC I study evaluated the efficacy of adalimumab induction therapy in 299 CD anti-TNF naive patients who were randomized to receive at weeks 0 and 2 adalimumab 40 mg/20 mg, 80 mg/40 mg, 160 mg/80 mg or placebo. The remission rate at week 4 (primary endpoint) for the 160 mg/80 mg adalimumab dosing arm was significantly different from placebo (36% vs 12%, respectively; P = 0.001). Clinical response (reduction of ≥100 points on the CDAI) for the 160 mg/80 mg adalimumab dosing arm was also significantly different from placebo at week 4 (50% vs 25%, respectively; P = 0.002). The CLASSIC II follow-up study showed that adalimumab was also effective for maintenance of clinical remission over one year. The CHARM trial evaluated the efficacy of adalimumab in the maintenance of response and remission in 854 patients with moderate to severe CD. Patients who responded (reduction of ≥70 points on the CDAI) to adalimumab (80 mg at week 0 and 40 mg at week 2) by week 4 were randomized to receive either adalimumab 40 mg weekly, adalimumab 40 mg every other week, or placebo through week 56. Remission rates among randomized responders (58% responded to the initial open-label treatment) at week 26 were 47% for patients who received adalimumab weekly, 40% for patients who received adalimumab every other week, and 17% for patients who received placebo (P < 0.001). At week 56, most patients maintained remission (36% adalimumab weekly arm, 41% adalimumab every other week arm, and 12% placebo arm, respectively; P < 0.001).
Synthesis and characterization of a coordinated oxoborane: Lewis acid stabilization of a boron-oxygen double bond

The first example of a stable oxoborane monomer (LBO) stabilized by complexation to AlCl3 has been prepared by the reaction of LAlCl2 with BCl3 followed by treatment with H2O in CH2Cl2 (L = [HC(CMe)2(NC6F5)2]). DFT calculations reveal that considerable boron−oxygen double bond character is retained in this complex.
Local moves and restrictions on the Jones polynomial

We analyze various local moves on knot diagrams to show that Jones polynomials must have certain algebraic properties. In particular, we show that the Jones polynomial of a knot cannot be a nontrivial monomial.
A Noise and Hearing Survey of Earth-Moving Equipment Operators

Abstract Noise and hearing were surveyed at 16 construction sites involving heavy earth-moving equipment operations. Over-all noise levels were 90-120 dB SPL with most energy below 600 cps. All measured noises exceeded eight-hour exposure criteria in one or more octave bands. Equipment operators showed hearing impairment which was worse at higher frequencies and which increased with years of employment even though corrected for age. Temporary hearing threshold shifts were found following single workday noise exposures. Survey findings indicated the need for noise control and audiometric monitoring.
Structure-activity relationships in coeliac-toxic gliadin peptides.

Computer modelling studies of two groups of biologically-active peptides derived from A-gliadin indicated that the most likely structures were α-helical ones, in the case of serine-containing peptides, and random peptides coil types featuring β-turns, in the case of proline-rich, tyrosine-containing peptides. The serine-containing group of peptides appear to be essentially cytotoxic in animal models of coeliac disease, whilst the tyrosine-containing group have the capacity to initiate damaging immunological reactions in patients with coeliac disease. Both types of activity in coeliac disease are only possible if there is defective digestion of the active peptides, as mucosal digestion studies indicate. In the case of the serine-containing peptides, activity of the peptides is linked to the presence of PSQQ and also probably QQQP motifs. With the tyrosine-containing peptides, sequences such as QQPY and/or QPYP are associated with immunological activity and hence toxicity.
Resistance of Josephson-junction arrays at low temperatures

We study the motion of vortices in arrays of Josephson junctions at zero temperature where it is controlled by quantum tunneling from one plaquette to another. The tunneling process is characterized by a finite time and can be slow compared to the superconducting gap (so that $\ensuremath{\tau}\ensuremath{\Delta}\ensuremath{\gg}1).$ The dissipation which accompanies this process arises from rare processes when a vortex excites a quasiparticle above the gap while tunneling through a single junction. We find that the dissipation is significant even in the case $\ensuremath{\tau}\ensuremath{\Delta}\ensuremath{\gg}1;$ in particular it is not exponentially small in this parameter. We use the calculated energy dissipation for the single vortex jump to estimate the physical resistance of the whole array.
Silicon chip-based patch-clamp electrodes integrated with PDMS microfluidics

We report on a silicon wafer-based device that can be used for recording macroscopic ion channel protein activities across a diverse group of cell-types. Gigaohm seals were achieved for CHO-K1 and RIN m5F cells, and both cell-attached and whole-cell mode configurations were also demonstrated. Two distinct intrinsic potassium ion channels were recorded in whole-cell mode for HIT-T15 and RAW 264.7 cells. Polydimethylsiloxane (PDMS) microfluidics were also coupled with the micromachined silicon chips in order to demonstrate that a single cell could be selectively directed to a micropore, and membrane protein currents could subsequently be recorded. These silicon chip-based devices have significant advantages over traditional micropipette approaches, and may serve as combinatorial tools for investigating membrane biophysics, pharmaceutical screening, and other bio-sensing tasks.
Measurement of blood flow in skin with an intact vascular pedicle.

: An experimental model was devised to confirm directly the validity of total skin blood flow measurement, as postulated by Sejrsen. A section of skin in the groin of the rat was prepared, which contained an intact artery and vein. Both of these were direct branches of the femoral vessels. When 133Xe was injected intrader-mally in saline solution, it was demonstrated that a sham isolated vascular pedicle cleared the isotope, and that the clearance was biexponential, suggesting two compartments. When the vascular pedicle was ligated, thereby removing direct blood flow to the piece of skin, the 133Xe clearance curve was mono exponential. It is concluded that the rapid portion of the bi exponential clearance curve, as analyzed by Sejrsen, does represent the dermal vascular components of isotope clearance, and that measurement of cutaneous blood flow by this method is a valid and useful technique. Results using this technique to follow rejection in a new skin transplant model are presented.
Changes in Photo-Aged Human Skin Following Topical Application of All-Trans Retinoic Acid

Although topical applications of retinoids on rodents and humans have been shown to cause epidermal hyperplasia, a detailed study of the influence of retinoids on epidermal differentiation in vivo has not been performed. In order to assess the pharmacologic effects of chronic topical tretinoin application used to improve the appearance of patients with photoaged skin, cutaneous biopsies from 25 patients in a controlled clinical study were examined histologically and immunocytochemically. Chronic application of tretinoin causes epidermal thickening (25 of 25 samples), stratum granulosum thickening (15 of 25), parakeratosis (13 of 25), a marked increase in the number of cell layers expressing epidermal transglutaminase (13 of 25), and focal expression of two keratins, K6 (12 of 25) and K13 (8 of 25), not normally expressed in the epidermis. The morphologic changes correlated with immunohistochemical abnormalities; neither of these correlated with the subjective cosmetic response. Three major epidermal differentiation products, keratins K1, K10, and K14 were not altered, within the limits of the methods used. Thus, chronic topical tretinoin reprograms some, but not all, aspects of human epidermal differentiation in vivo.
Cardiorespiratory Fitness and Proximity to Commercial Physical Activity Facilities Among 12th Grade Girls

Abstract Purpose To investigate the relationship between proximity to commercial physical activity (PA) facilities and cardiorespiratory fitness of 12th grade girls. Methods Adolescent girls (n = 786, 60% African American, mean age=17.6 ± .6 years) performed a submaximal fitness test (Physical Work Capacity 170 test). Commercial PA facilities were mapped and counted within a .75-mile street-network buffer around girls' homes using Geographic Information Systems. Sedentary activities and vigorous physical activity (≥6 metabolic equivalents) were determined by the average number of 30-minute blocks reported per day on the 3-Day Physical Activity Recall. Mixed model regressions were calculated using school as a random variable. Results Girls had higher weight-relative Physical Work Capacity 170 test scores if there was a commercial PA facility (n = 186, 12.4 ± 4.2 kg m/min/kg) within a .75-mile street-network buffer of home as compared with girls without a nearby facility (n = 600, 11.2 ± 3.6 kg m/min/kg). After adjusting for demographic variables, sports participation, sedentary behaviors, and vigorous physical activity, having one or more commercial PA facilities within a .75-mile street-network buffer of homes was significantly related to cardiorespiratory fitness. Conclusions Both with and without adjustment for covariates, the presence of a commercial PA facility within a .75-mile street-network buffer of a girl's home was associated with higher cardiorespiratory fitness.
Requirements for the selective degradation of endoplasmic reticulum-resident major histocompatibility complex class I proteins by the viral immune evasion molecule mK3

Recent studies suggest that certain viral proteins co-opt endoplasmic reticulum (ER) degradation pathways to prevent the surface display of major histocompatibility complex class I molecules to the immune system. A novel example of such a molecule is the mK3 protein of gammaherpesvirus 68. mK3 belongs to an extensive family of structurally similar viral and cellular proteins that function as ubiquitin ligases using a conserved RING-CH domain. In the specific case of mK3, it selectively targets the rapid degradation of nascent class I heavy chains in the ER while they are associated with the class I peptide-loading complex (PLC). We present here evidence that the PLC imposes a relative proximity and/or orientation on the RING-CH domain of mK3 that is required for it to specifically target class I molecules for degradation. Furthermore, we demonstrate that full assembly of class I molecules with peptide is not a prerequisite for mK3-mediated degradation. Surprisingly, although the cytosolic tail of class I is required for rapid mK3-mediated degradation, we observed that a class I mutant lacking lysine residues in its cytosolic tail was ubiquitinated and degraded in the presence of mK3 in a manner indistinguishable from wild-type class I molecules. These findings are consistent with a “partial dislocation” model for turnover of ER proteins and define some common features of ER degradation pathways initiated by structurally distinct herpesvirus proteins.
Posterior stabilization of subaxial cervical spine trauma: indications and techniques.

Summary The use of instrumentation for stabilization following cervical trauma has evolved rapidly in the past few decades. Nonoperative maneuvers, including traction, extended bed rest, and cast immobilization, have given way to wiring or screw rod constructs that allow immediate fixation and early mobilization of the patient. These procedures can be performed soon after trauma and with a minimum of surgical risk. They offer immediate stability of the injured spine, and can prevent the sequelae of acute cervical spinal cord injury that may accompany prolonged bed rest, thus allowing early rehabilitation and the potential for improved recovery. Current techniques for posterior cervical spine stabilization following trauma include spinous process or facet wiring [1–9], lateral mass plating [10–18], and cervical pedicle screws [19–27]. Several radiological tools, including MRI [28] and reformatted CT, yield precise details of the injured spine and allow the treating physician to determine which, if any, fixation technique offers the best chance of recovery with the least amount of risk. The goals of surgery following acute cervical spine injury include decompressing the injured spinal cord or nerve root, maintaining alignment, providing stability to the spine, promoting healing and fusion, and allowing early mobilization. This article will review indications for posterior cervical spine surgery, as well as the techniques that are currently available to help achieve the above-noted goals. We also report a recent retrospective review of 5-year data in treating posterior cervical trauma with lateral mass and pedicle screw fixation.
Prospective Elementary Teachers' Perceptions of Real-Life Connections Reflected in Posing and Evaluating Story Problems.

This study explored prospective elementary teachers’ perspectives on real-life connections in the case of story problems. A series of tasks were designed to uncover the participants’ collective perceptions of real-life connections by speculating on participants’ emerging beliefs about real-life connections and how their beliefs were reflected in the story problems they posed or evaluated. Findings revealed the following ideas: (a) there were overly positive beliefs with insufficient specifics; (b) participants perceived utility and reality as critical components of real-life connections; and (c) there were vast discrepancies between their beliefs and the way they posed or evaluated story problems for real-life connections. These results will generate further discussions about the issues and challenges teacher education programs face, while providing suggestions for future research.
Prevalence of deep venous reflux in patients with primary superficial vein incompetence

Abstract Purpose: This prospective study was designed to determine the prevalence of deep reflux and the conditions under which it may occur in patients with primary superficial venous reflux and absence of deep venous thrombosis (DVT). Methods: We studied 152 limbs in 120 consecutive patients in the standing position who had superficial venous reflux with color flow duplex scanning. Limbs with documented evidence of DVT or post-thrombotic vein wall changes during the examination were studied but not included in the analysis. Limbs were divided into those that had at least reflux in the saphenofemoral, the saphenopopliteal, or the gastropopliteal junction and into those with nonjunctional reflux in the superficial and gastrocnemial veins. Peak velocity and duration of reflux were measured. To examine the recirculation theory, we tested the deep veins by occluding and refluxing saphenous veins 10 cm below the sampling site. Results: Thirteen limbs in 11 patients (9%) were excluded because of previous DVT. Of the remaining 139 limbs, 106 (76%) had junctional reflux. Saphenofemoral junction was involved in 89 limbs (84%), saphenopopliteal junction in 18 (17%), and gastropopliteal junction in 7 (4%). In 33 limbs (24%), reflux was detected in the main trunk or tributaries of the saphenous veins alone with no junctional incompetence. Femoral or popliteal reflux was present in 31 limbs (22%). This reflux was segmental in 27 limbs, and it was limited in the junction in 24 limbs. The mean duration of deep venous reflux was 0.9 seconds, it ranged from 0.6 to 3.7 seconds, and it was significantly shorter than that in the superficial veins (2.6 seconds; P P =.038). The mean duration of deep venous reflux in these groups was comparable (0.85 seconds vs 0.91 seconds; P =.44). Occlusion of the incompetent superficial veins reduced somewhat the duration of the deep venous reflux but did not abolish it (0.88 seconds vs 0.82 seconds; P =.072). The presence of DVI was associated with junctional reflux of high peak velocity and long duration. Conclusions: The prevalence of DVI in patients with primary superficial venous reflux and without history of DVT is 22%. However, this reflux is segmental, mainly in the common femoral vein, and is of short duration. It is associated with the presence of junctional incompetence that has a high peak velocity and long duration. These findings may explain why surgical correction of superficial reflux abolishes DVI. (J Vasc Surg 2000;32:663-8.)
Accent, Perpetual Foreigner Stereotype, and Perceived Discrimination as Indirect Links Between English Proficiency and Depressive Symptoms in Chinese American Adolescents

The current study uses Garcia Coll et al.'s (1996) developmental competence model of ethnic minority children and Kim's (1999) racial triangulation theory as frameworks for investigating the mechanisms whereby early adolescent English proficiency relates to perceived discriminatory experiences and adolescent depressive symptoms. Data from 444 adolescents (239 girls and 205 boys, with a mean age of 13.0 years for Wave 1 and 17.0 years for Wave 2) and their parents living in major metropolitan areas of Northern California were collected. The structural equation modeling analyses indicate that self-reported low levels of English proficiency among Chinese American adolescents in middle school are related to these same students later reporting that they speak English with an accent in high school, which in turn relates significantly to their perceiving that they have been stereotyped as perpetual foreigners. For girls, a perpetual foreigner stereotype relates to perceptions of chronic daily discrimination, increasing the risk of depressive symptoms. For boys, the path is different: A perpetual foreigner stereotype is apparently related to discriminatory victimization experiences, which increase the risk of depressive symptoms.
Characterization of a cyclic oligomer of poly(pentamethylene terephthalamide)

Abstract Poly(pentamethylene terephthalamide) made by interfacial polycondensation contained 20% of a fraction that was more soluble in concentrated aqueous H 2 SO 4 solutions. The more soluble fraction was sublimable. It had the correct elemental analysis for (C 18 H 16 O 4 ) n but the endotherm pattern on differential thermal analysis was quite different from that for the major fraction. The crystals formed on sublimation of the more soluble fraction were elongated lamella in which the polyamide units were probably hydrogen bonded parallel to the long crystal axis. Mass spectrometry of the crystals indicated a molecular weight of 464. This fact, combined with the evidence of the elemental analysis, indicates that the sublimable crystals are (C 18 H 16 O 4 ) 2 , the cyclic dimer of pentamethylene terephthalamide.
MODELING OF HYDROPROCESSING REACTIONS

Langmuir-Hinshelwood-Hougen-Watson rate expressions are developed for the hydroprocessing of quinoline, naphthalene and dibenzothiophene based on batch reactor data at 350°C and at 500 psig. Based on competitive adsorption, the kinetics are extended to binary mixtures of quinoline/naphtha-lene and quinoline/dibenzothiophene. In doing so, the differences in hydrogenation and hydro-genolysis sites are taken into consideration. In all cases, the agreement between the predicted and experimental results are good
Calcium in biological systems

Abstract In physiological fluids calcium ion takes part in many processes. Among these are muscle contraction, microtubule formation, hormonal responses, exocytosis, fertilization, neurotransmitter release, blood clotting, protein stabilization, intercellular communication, mineralization, and cell fusion, adhesion, and growth. Most of these Ca2+ related activities occur by interactions with proteins, which Ca2+ may stabilize, activate, and modulate. In extracellular fluids the free or weakly bound Ca2+ concentration is about 1 mM. Within many cells the free Ca2+ concentration in the cytosol is only 0.1 μM, 10−4 times less than in extracellular fluids. Cell membranes contain pumps, Ca-ATPases, that aid in maintaining the extraordinary concentration gradient. However, a substantial amount of Ca2+ occurs within cells, some of it bound tightly to proteins. In response to a stimulus the free Ca2+ concentration may increase about 10 times. Thus proteins that participate in these responses possess Ca2+ dissociation constants in the μM range. The cytosolic Ca2+ concentration change is achieved rapidly, and free Ca2+ serves as a messenger or trigger for other interactions. Ca2+ sites in proteins are composed of negatively charged and neutral oxygen donors; nitrogen donors seem unlikely, and none have been found. Protein oxygen donors derive from carboxylate groups, carbonyl oxygens of the amide backbone, and hydroxy groups of serine and threonine side chains. Ca2+ varies in its coordination number and bond lengths. The frequency of Ca2+ coordination numbers decreases in the order 8 > 7 > 6 > 9. Coordination about Ca2+ is basically ionic and spherical. Ca2+O bond distances range from 2.3 to 2.6 A. In solution, even within a single complex, there may be variability in bond distances and, in many cases, coordination number. To bind Ca2+, proteins provide a pocket of appropriate size and shape with two or more negatively charged carboxylate side chains. Specific applications of these general principles appear in other papers in this symposium and in Vol. 17 of ‘Metal Ions in Biological Systems’, H. Sigel, ed. Except for the charge difference, usually not crucial, tripositive lanthanide ions mimic many Ca2+ properties. Energy transfer from a nearby excited aromatic chromophore produces Tb3+ luminescence. The spectrum and relative intensity compared to the total luminescence intensity of the circularly polarized luminescence from parvalbumin and troponin-C are nearly identical. Specific Ca2+ binding sites in the two kinds of proteins are therefore similar. The excitation spectrum identifies the donor group in the energy transfer process as a phenylalanine side chain in parvalbumin and a tyrosine side chain in troponin-C. The two amine acids comprise homologous pairs in the two proteins.
ABO isoimmunization: the use of the specific Coombs and heat elution tests in the detection of hemolytic disease

Summary A method of early recognition and identification of ABO erythroblastosis is presented. This involves the use of a potent antihuman globulin serum which has been pretested for its ability to detect adsorbed antibodies of the gamma and nongamma globulin varieties. When a positive Coombs test is found on a sample of blood from the umbilical cord, the infant's cells are treated by the heat elution method for the removal of adsorbed antibodies. The eluates thus obtained are tested against a panel of cells containing known antigens, and the specific antibodies are identified. With this early information, the physician is forewarned of the possible development of clinical disease. In our series, which includes over 316 cases of ABO isoimmunization detected by this approach, it was found that the incidence of ABO isoimmunization approximates that of Rh-Hr incompatibilities. The occurrence of clinical disease in the ABO group was much less frequent, however. Of the 3,921 heterospecific pregnancies to the ABO system, 316 infants showed positive direct Coombs tests. When heat elution tests were done on blood taken from the infant's umbilical cord, 183 or 57.91 per cent were specific for the A antigen, 28 or 8.86 per cent agglutinated only B erythrocytes, and 105 or 33.22 per cent reacted with both A and B red blood cells and appeared to be the anti-C of Wiener.
USE OF EXPANDED COLOR SCALES TO PREDICT CHEMICAL AND VISUAL CHANGES IN SOLUTIONS

Cranberry juice cocktail was chosen as a typical red fruit juice. Samples were heated at 65°C to simulate pigment degradation on storage. The heated samples were ranked for color visually and objectively using a Hunter Color Meter, a Gardner Color Meter and a G.E. recording spec-trophotometer. Most functions of color obtained from the instrument correlated highly with visual color except dominant wavelength, hue, and Hunter and Gardner b. Most instrumental values also correlated well with anthocyanin concentration except the three above. The expanded L, a*, b* scales, which were developed in previous work to eliminate the inversion of tristimulus scales with pigment concentration with dark beverages, also gave very high correlations with visual evaluations and with anthocyanin concentrations.
Frequency‐dependent refraction and multipathing of 10–100 second surface waves in the western Pacific

We use a multi-taper spectral estimation procedure to measure the frequency dependence of particle motion polarizations of long- and intermediate-period fundamental mode Rayleigh and Love waves propagating across the thermally mature northwestern Pacific. Frequency-dependent polarization parameters are measured for separated time windows for direct body phases, surface wave Airy arrivals, and early and late surface wave coda. The multi-taper method has optimum spectral leakage properties for short time windows and supplies a framework for computing error estimates for polarization parameters. Our initial results show that surface waves between 10 and 100 mHz are strongly refracted by lateral heterogeneity in the northwestern Pacific. The frequency dependence of this refraction appears to be relatively simple.
The ε expansion of pomeron amplitudes

Abstract The indices η, ν and γ which characterize the high energy-behavior of the elastic scattering amplitude in the presence of a non-vanishing triple-pomeron interaction are calculated to order ϵ 2 where 4-ϵ is the dimension of the space of transverse momenta. At the physical value ϵ = 2 these corrections to η and ν are larger than the ϵ terms calculated by Migdal, Polyakov and Ter-Martirosyan and Abarbanel and Bronzan.
Education for National Development: World Bank Activities.

It is now widely accepted that education contributes to national and economic development. Multilateral agencies, like the World Bank, have played a key role in financing levels and types of education which might not have been implemented otherwise. The lending priority on types of project depends upon the country and agency polities towards education. In a dynamic world, such policies are by necessity an evolving concept. This article is divided into two sections: The first discusses the World Bank's actions in education for national development; the second section illustrates a recent major policy change away from educational 'hardware' and buildings towards new curricula, textbooks and other elements required for improving the quality of education.
Factors associated with early childhood caries incidence among high caries-risk children.

Objectives To assess the relationships between different behavioral factors and Early Childhood Caries (ECC) in African-American pre-school children.
Endothelin, astrocytes and glaucoma

It has become increasingly clear that astrocytes may play an important role in the genesis of glaucoma. Astrogliosis occurs in response to ocular stress or the presence of noxious stimuli. Agents that appear to stimulate reactive gliosis are becoming increasingly clear. One class of agents that is emerging is the endothelins (ETs; specifically, ET-1). In this review we examine the interactions of ET-1 with astrocytes and provide examples where ET-1 appears to contribute to activation of astrocytes and play a role in the neurodegenerative effects that accompany such reactivation resulting in astrogliosis. These actions are presented in the context of glaucoma although information is also presented with respect to ET-1's role in the central nervous system and brain. While much has been learned with respect to ET-1/astrocyte interactions, there are still a number of questions concerning the potential therapeutic implications of these findings. Hopefully this review will stimulate others to examine this potential.
Doubling of Chebyshev correlation function for calculating narrow resonances using low-storage filter diagonalization

Abstract It is well established that a Chebyshev correlation function of the length 2 K can be calculated from a K -step Chebyshev propagation. Here, we propose an ansatz that such a doubling scheme can also be utilized to calculate positions and widths of narrow resonances using the low-storage filter diagonalization (LSFD) based on the damped Chebyshev propagation. This ansatz, which is shown to be numerically valid in two real molecular systems (HCO(X) and SO 2 (C)), reduces the computational cost by half.
On the Progression of Impact Fees

Abstract This article examines various methods of assessing impact fees to cover infrastructure costs in terms of their socioeconomic consequences, and proposes an approach that appears to be more equitable than currently used techniques.
Simple codes versus efficient codes

Transmission of information is an important function of cortical neurons, so it is conceivable that they have evolved to transmit information efficiently, with low noise and high temporal precision. Such precision is consistent with the output generated by various working models that mimick neuronal activity, from simple integrate-and-fire models to elaborate numerical simulations of realistic-looking neurons. But our current inability to match this data with neurons' detailed spike-generating mechanisms in vivo allows us a wide latitude in interpreting the significance of the various components of their spike code. One extreme hypothesis, the ‘simple’ model, is that each neuron is noisy and slow, performing a simple computation and transmitting a small amount of information. A competing hypothesis, the ‘efficient’ model, postulates that a neuron transmits large amounts of information through precise, complex, single-spike computations. Both hypotheses are broadly consistent with the available data. The conflict may only be resolved with the development of new measurement techniques that will allow one to investigate directly the properties that make a neuron efficient — that is, to be able to measure highly transient, localized events inside the thinnest dendrites, which are currently experimentally inaccessible.
Distributed Cooperative Outdoor Multirobot Localization and Mapping

The subject of this article is a scheme for distributed outdoor localization of a team of robots and the use of the robot team for outdoor terrain mapping. Localization is accomplished via Extended Kalman Filtering (EKF). In the distributed EKF-based scheme for localization, heterogeneity of the available sensors is exploited in the absence or degradation of absolute sensors aboard the team members. The terrain mapping technique then utilizes localization information to facilitate the fusion of vision-based range information of environmental features with changes in elevation profile across the terrain. The result is a terrain matrix from which a metric map is then generated. The proposed algorithms are implemented using field data obtained from a team of robots traversing an uneven outdoor terrain.
Quantitative studies of the bacterial flora of the periodontium in rice rats.

Abstract Eighteen 21-week old rice rats were scored for periodontal disease according to the method of Gupta and Shaw (1956). The molar teeth and periodontium of one side of the heads were weighed, and ground in broth. Dilutions determined in preliminary trials were plated in 0·1 ml amounts on each of five plates of the following media: horse blood agar, Na azide agar, nutrient agar, EMB agar, Rogosa SL agar, serum tellurite agar. The blood agar was incubated anaerobically for 5 days, other media aerobically for 3 days. Colony counts were made at 10 × magnification with a stereoscopic microscope. Total counts from growth on blood agar incubated anaerobically ranged from 3·6 × 10 7 to 3·6 × 10 10 per total sample. Counts averaged 3·4 × 10 8 for twelve animals with periodontal scores of 57 or less, and more than 1·6 × 10 10 for six animals with scores exceeding 100. Enterococci were the most numerous organisms, counts ranging from 2·0 × 10 6 to 3·5 × 10 10 . High counts, averaging 1·4 × 10 10 , were associated with high periodontal disease scores. Actinobacillus counts ranged from 1·0 to 5·6 × 10 8 for the four rice rats with highest periodontal scores. Except for one animal, remaining Actinobacillus counts averaged 6·9 × 10 6 . The only other regularly occurring organisms were diphtheroids ranging in counts from 3·0 × 10 5 to 7·3 × 10 7 and unrelated to periodontal disease. Staphylococci, coliforms and lactobacilli each appeared on plates from over half the animals, usually in the ranges 10 6 –10 7 , 10 4 –10 5 , 10 3 –10 6 , respectively. Fusobacterium , although observed only twice, numbered 1·2 × 10 8 in one animal.
Association of lipids and proteins in chloroplast lamellar membrane

Abstract 1. 1. To study the nature of lipid association with protein in biological membranes, lipids with different hydrophilic groups were reassociated with chloroplast membrane proteins. 2. 2. For stoichiometric reassociation of lipids with protein, a convenient method, a double dialysis procedure, was developed and its validity was examined. 3. 3. Saturation of lipid association occurred when 36 moles of palmitic acid, 30 moles of chlorophyll, 16 moles of monogalactosyl diglyceride, 15 moles of phosphatidyl glycerol or digalactosyl diglyceride, 6 moles of dihydrophytyl ether phosphatidyl glycerophosphate or 1 mole of β-carotene was bound per mole of lamellar protein. 4. 4. In the presence of competitors, reassociation of monogalactosyl diglcyeride or chlorophyll with protein was shown to be dependent upon the nature of the hydrophobic moiety of competing amphipathic lipids and independent of their hydrophilic groups. 5. 5. These data provide evidence for hydrophobic association of lipids with chloroplast lamellar proteins.
The Path to American Intervention in the First World War: Implications for Understanding the Foreign Policy Choices of Democratic States

This essay contributes to the democratic peace debates by developing observable expectations about the foreign policy choices of democratic states from a range of theoretical perspective within the democratic peace literature. These expectations are then evaluated against the behavior of American decision makers prior to U.S. entry into the First World War (1914–1917). Of the three perspectives considered, the evidence indicates that pacifism did not significantly constrain American policy in this period. Some evidence is found supporting expectations derived from the rational choice theory of the democratic peace, though the social identity account of the democratic peace is found to provide the most compelling explanation for American behavior between 1914 and 1917.
A method of achieving accurate zero-field conditions using muonium

In some zero-field μSR experiments the outcome depends on reducing stray external magnetic fields to very low levels. These fields may originate from the Earth, nearby accelerators, and residual fields from spectrometer magnets. We describe a method of determining appropriate trim coil currents to zero the field, which avoids the observation of very low unwanted muon precession frequencies. This method depends on measuring the muonium precession frequencies in a set of x-, y- and z-axis weak transverse field scans, and then calculating the necessary currents to achieve practically zero net field.
Atomic Level Anisotropy in the Electrostatic Modeling of Lone Pairs for a Polarizable Force Field Based on the Classical Drude Oscillator

Electron pairs in the valence shell of an atom that do not participate in the bonding of a molecule (“lone pairs”) give rise to a concentrated electron density away from the atom center. To account for the asymmetry in the electron charge density that arises from lone pairs, an electrostatic model is developed that is parametrically anisotropic at the atomic level. The model uses virtual interaction sites with partial charges that are associated but not coincident with the nuclei. In addition, the model incorporates anisotropic atomic polarizabilities. The protocol previously outlined in Anisimov et al. [J. Chem. Theory Comput. 2005, 1, 153] for parametrizing the electrostatic potential energy of a polarizable force field using classical Drude oscillators is extended to incorporate additional lone pair parameters. To probe the electrostatic environment around the lone pairs, the static (molecule alone) and perturbed (molecule in the presence of a test charge) electrostatic potential (ESP) are evaluated an...