cssi/SciSciGPT-SciSciNet huggingface dataset:
Active control of wave-type vibration energy for improved structural reliability

Abstract Degradation of the structural integrity of flexible, composite structures occurs over time when subjected to vibratory disturbances. Active vibration control methods present a way to minimize vibration levels in structures for improved structural reliability. Control architectures which have been developed and specialized for vibration reduction in flexible structures are presented. These are based on the interpretation of vibration behavior in the form of waveform propagation and modal response. To reduce the potential energy of a structure with vibration characteristics dominated by standing waves, a nonlinear rate-feedback scheme and a dual-controller scheme for both transient and steady-state vibration minimization have been developed. Vibration inflexible structures may also be dominated by travelling waves with standing wave components superimposed. A new concept, the total energy absorption (TEA) compensator, allows control of stationary and propagating waveforms in flexible structures based on feedback of wavetype energy-field measurements. The TEA formulation considers vibration energy fields in the structure in the form of complex intensity and energy density for effective vibration minimization. Lightweight piezoelectric materials and accelerometers are used as sensors to estimate the energyfield parameters. Piezoelectric materials are used as distributed actuators to drive the flexible structure. Numerical and experimental results on the reduction of the total vibrational energy in flexible structures using these active control methods are presented.
Inhibition of the progress of transcription on the tryptophan operon of Escherichia coli

Abstract It has been reported that when l -tryptophan is added to tryptophan-deprived cells of Escherichia coli , transcription which is in progress over the most operator-proximal region of trpE , the first structural gene of the tryptophan operon ( trpO-E-D-C-B-A ), is inhibited immediately (Imamoto, 1968, 1970). In this paper we show that transcription inhibition is not restricted to the initial segment of trpE ; rather, there is a gradient of inhibition throughout the operon, with transcription of trpE inhibited most severely. We also find that this inhibition of the progression of transcription occurs in a repressor-negative amber mutant ( trpR ); thus the inhibition does not involve the operon-specific repression system. In a strain in which trpE is deleted, severe inhibition of transcription is observed for trpD , the gene which is now located immediately adjacent to the operator. The inhibition is independent of the normal function of the RNA synthesis control gene, rel , and is not affected by a polarity relief suppressor, suA . Attempts to show that abnormally rapid degradation is responsible for the reduction in detectable trp mRNA were unsuccessful.
Cognitive Set and Coping Strategy Affect Mothers' Sensitivity to Infant Cries: A Signal Detection Approach

We used Signal Detection methodology to examine how cognitive set affects mothers' response to an infant cry. We asked whether a cry from a "difficult" versus an "easy" infant would elicit a change in sensitivity or response bias in mothers' processing of these cries. Thirty-eight mothers of 4- to 6-month-old infants participated in a Signal Detection task in which they were asked whether they could detect differences between a standard cry and 1 of 4 cry variants. Cry variants differed from the standard cry in small, systematic changes in fundamental frequency. The task was conducted in 2 parts; each part constituted a condition wherein mothers received a cognitive set manipulation that labeled the identical cry as coming from either a "difficult'" or an "easy" infant. An increase in mothers' sensitivity was associated with the "difficult" infant cognitive set. We examined as well how a coping strategy (illusion of control) affected cry signal processing. Mothers who exhibited high illusory control were least sensitive in detecting differences between cries. Two informationprocessing measures, response time and heart rate, were also collected and showed that greater sensitivity was associated with more efficient processing of the cry signal.
Oral aspects of paget's disease, including case reports and necropsy findings

Abstract The present etiological and pathologic knowledge of Paget's disease is summarized. It has been pointed out that biopsy studies are indicated as an aid to diagnosis in order to be able to differentiate Paget's disease from osteitis fibrosa, as both conditions may produce similar clinical and roentgenologic findings, especially when clinical changes are noted in the mandible. X-rays of the skull and, at times, of the long bones are necessary to establish a diagnosis. Five case reports are added of patients with oral changes in this disease these include necropsy findings of the jaws.
NUCLEAR MISBEHAVIOR IN AN ABERRANT INBRED TETRAHYMENA.

SYNOPSIS. Breeding anomalies in an inbred strain (B1) of syngen 1, Tetrahymena pyriformis, are traced to aberrant chromosomal constitutions of the micronuclei. The origins of the micronuclear defects have not been established, but they probably arise in much the same manner as those observed earlier in “semi-amicronucleate” clones, except that they occur later and in lower frequencies. The abnormal nuclei are impaired in their ability to carry out the maneuvers required for normal conjugation; some are blocked in MI, most after MII; the occasional cells in which nuclear reorganization is completed have visibly defective macronuclear anlagen and are inviable. When crossed to normal strains, nuclear misbehavior is induced in them and again very few if any viable exconjugants are produced. The details of the aberrations are discussed with reference to the patterns of nucleocytoplasmic interaction in conjugation.
The first exit time of a Brownian motion from an unbounded convex domain

Consider the first exit time τD of a (d+1)-dimensional Brownian motion from an unbounded open domain D=\set(x,y)∈\Rd+1\dvtxy>f(x),x∈\Rd starting at\vspace{0.5pt} (x0,f(x0)+1)∈\Rd+1 for some x0∈\Rd, where the function f(x) on \Rd is convex and f(x)→∞ as the Euclidean norm |x|→∞. Very general estimates for the asymptotics of log\prτD>t are given by using Gaussian techniques. In particular, for f(x)=exp{|x|p}, p>0, limt→∞t−1(logt)2/plog\prτD>t=−j2ν/2, where ν=(d−2)/2 and jν is the smallest positive zero of the Bessel function Jν.
Generalized geometric programming with many equality constraints

A monomial treatment for solving mixed equality/inequality constrained generalized geometric programs is presented. The method is shown to be equivalent to a Newton–Raphson procedure carried out in log space on the equality constraints at the same time that a cutting plane procedure is performed on a convex region constrained within the feasible region of the inequality constraints. Known limitations of this monomial treatment are outlined and a technique for improving the efficiency of the GGP method is suggested. A discussion of how other methods of solving mixed equality/inequality constrained GGP problems compare to the monomial treatment is presented and two example problems are solved.
Effect of stabilizing media on zone mobility and spreading in electrophoresis

The migration process for charged particles in a stabilizing medium is considered in terms of two steps: (1) a step in which migration is halted by an obstruction for a sufficient time to allow diffusion around the obstruction, and (2) a step in which normal, interstitial migration is occurring. Mathematical formulation of the two-step process leads to an expression for apparent mobility which, contrary to other theories, is a function of the field strength. The same process leads to a significant spreading of zones which is important at high voltages or for migrants with a large effective charge. The conclusions of this theory are compared with experimental evidence relating to zone mobility and structure.
Folding of pig gastric mucin non-glycosylated domains: a discrete molecular dynamics study

Mucin glycoproteins consist of tandem-repeating glycosylated regions flanked by non-repetitive protein domains with little glycosylation. These non-repetitive domains are involved in polymerization of mucin and play an important role in the pH-dependent gelation of gastric mucin, which is essential for protecting the stomach from autodigestion. We examine folding of the non-repetitive sequence of PGM-2X (242 amino acids) and the von Willebrand factor vWF-C1 domain (67 amino acids) at neutral and low pH using discrete molecular dynamics (DMD) in an implicit solvent combined with a four-bead peptide model. Using the same implicit solvent parameters, folding of both domains is simulated at neutral and low pH. In contrast to vWF-C1, PGM-2X folding is strongly affected by pH as indicated by changes in the contact order, radius of gyration, free-energy landscape, and the secondary structure. Whereas the free-energy landscape of vWF-C1 shows a single minimum at both neutral and low pH, the free-energy landscape of PGM-2X is characterized by multiple minima that are more numerous and shallower at low pH. Detailed structural analysis shows that PGM-2X partially unfolds at low pH. This partial unfolding is facilitated by the C-terminal region GLU236-PRO242, which loses contact with the rest of the domain due to effective “mean-field” repulsion among highly positively charged N- and C-terminal regions. Consequently, at low pH, hydrophobic amino acids are more exposed to the solvent. In vWF-C1, low pH induces some structural changes, including an increased exposure of CYS at position 67, but these changes are small compared to those found in PGM-2X. For PGM-2X, the DMD-derived average β-strand propensity increases from 0.26 ± 0.01 at neutral pH to 0.38 ± 0.01 at low pH. For vWF-C1, the DMD-derived average β-strand propensity is 0.32 ± 0.02 at neutral pH and 0.35 ± 0.02 at low pH. The DMD-derived structural information provides insight into pH-induced changes in the folding of two distinct mucin domains and suggests plausible mechanisms of the aggregation/gelation of mucin.
Stability of Toxin Producing Attribute of Scarlet Fever Strains of Streptococci

SummaryThe use of several recognized methods for dissociation of bacteria when applied to scarlet fever strains of streptococci failed to deprive these strains of their ability to produce toxin.
PROOF OF THE IMPOSSIBILITY OF A CLASSICAL ACTION PRINCIPLE FOR MAGNETIC MONOPOLES AND CHARGES WITHOUT SUBSIDIARY CONDITIONS

A proof is given that no action principle exists for the classical electromagnetic field when its sources are both charged particles and magnetic monopoles unless an extra condition, not derivable from the action principle, is assumed. The extra condition is that charges never touch magnetic monopoles. The Lorentz force law predicts that a charge and a magnetic monopole approaching each other along a straight line will collide. Since the Lorentz force law can only be gotten from an action principle with the aid of this extra condition, the necessary extra condition is in contradiction to the law derived with its help. Thus there is no satisfactory action principle for the classical electromagnetic field if both charges and magnetic monopoles exist. The foregoing provides an aesthetic argument against the existence of magnetic monopoles. An action principle has then been constructed using the extra condition. It is analogous to the usual action principle for (charge-only) electromagnetic theory, but ${J}^{\ensuremath{\nu}}{A}_{\ensuremath{\nu}}$ is replaced by ${J}^{\ensuremath{\nu}}{R}_{\ensuremath{\nu}}\ensuremath{\rightarrow}{K}^{\ensuremath{\nu}}{T}_{\ensuremath{\nu}}$ where ${J}^{\ensuremath{\nu}}$ and ${K}_{\ensuremath{\nu}}$ are the 4-dimensional current and magnetic monopole densities, respectively, and ${R}_{\ensuremath{\nu}}$ and ${T}_{\ensuremath{\nu}}$ are gaugeless "effective potentials." Electromagnetic theory is formulated in a gaugeless way in terms of these effective potentials in the Appendix.
Using college alumni populations in epidemiologic research : the UNC alumni heart study

Abstract The UNC Alumni Heart Study (UNCAHS) is a prospective study of the role of psychosocial factors, in particular hostility, in the development of coronary heart disease. The target population is composed of persons who completed the Minnesota Multiphasic Personality Inventory while attending the University of North Carolina in the mid-1960x. Logistic regression analyses were used to determine whether hostility, demographic and other variables were significant determinants of the subjects' locatability and participation. It was found that MMPI hostility scores at initial testing were unrelated to either potential or actual locatability or participation. Thus there is no evidence that hostility is the source of selection bias in the UNCAHS. Selection into the study was predicted by age, sex, degree status and variables concerned with the conditions under which the MMPI was administered. It is concluded that follow-up studies of college cohorts may have study-specific sources of selection bias.
Spectral mixture analysis of Landsat thematic mapper images applied to the detection of the transient snowline on tropical Andean glaciers

Abstract The tropical glaciers in the central Andes are sensitive indicators of climatic variability. They are an important water resource, but are presently in a state of rapid retreat. Spectral mixture analysis using Landsat Thematic Mapper (TM) images was used to identify the ablation and accumulation zones and the transient snowline at two tropical sites: Zongo Glacier in the Cordillera Real, Bolivia, and the Quelccaya Ice Cap in Peru. Delineation of the accumulation and ablation zones is relatively insensitive to the endmembers selected to represent each zone. Endmembers selected from Zongo Glacier were successfully used to delineate accumulation and ablation zones on the Quelccaya Ice Cap. Spectral mixture analysis was found to be superior to a single band image or the TM4/TM5 ratio in discriminating the accumulation and ablation zones on these small tropical glaciers. The altitude of the transient snowline identified on Zongo Glacier at the end of the ablation season is consistent with the altitude of the equilibrium line determined from mass balance studies. This suggests that in the tropics, as in mid-latitudes, the highest altitude reached by the transient snowline during a hydrological year can be used as a proxy for the altitude of the equilibrium line.
Right ventricular hypertension and pulmonary stenosis in Ebstein's anomaly of the heart.

Abstract A child is presented with Ebstein's malformation of the tricuspid valve associated with pulmonary stenosis and ventricular septal defect producing moderately severe right ventricular hypertension. A search of the literature fails to reveal another case of Ebstein's anomaly with either severe right ventricular hypertension or with a significant gradient across the pulmonary valve. In this instance the diagnosis was not suspected because of the predominance of the clinical findings referable to the accompanying lesions. Extreme cardiac irritability and progressive conduction defects should suggest the diagnosis of Ebstein's anomaly. This may be confirmed with the intracardiac electrode catheter.
Elastic moduli of cemented sphere packs

Abstract We present a method for estimating the effective elastic moduli of a dense random pack of identical elastic spheres with elastic binder (cement). The cement concentration in the pore space varies from a few percent (where it fills the space at grain contacts) to 100%. To construct the solution we start at a small cement concentration value where the effective moduli of the pack are given by the contact cement theory (CCT). The next, and most important, step is to obtain the (unknown a priori) elastic moduli at 100% cement concentration. To do so, we: (1) treat the starting cemented pack, that is a three-phase system of grains, cement, and voids, as an elastically equivalent two-phase system of voids in a homogeneous matrix; (2) apply an effective medium theory (EMT) to find the elastic moduli of this matrix; and (3) calculate the effective moduli of this matrix with the voids filled with cement. We treat these moduli as the desired moduli of the pack with 100% cement concentration. We interpolate between this point and the initial (small cement concentration) point by using the EMT to populate the no-void elastic body with voids. Using CCT as the initial construction point gives us control over the microstructure of the composite which proves to be crucial in this modeling. The results predict the compressional elastic modulus (that is the product of density and compressional-wave velocity squared) from wave-propagation experiments on epoxy-cemented glass beads, ice-cemented Ottawa sand, and in-situ acoustic data in natural sands cemented by gas hydrate within experimental accuracy.
Diagnosis and treatment of abductor hallucis focal dystonia with botulinum toxin injection: a case presentation.

treatment. Focal dystonia is a rare neurologic condition that often limits function and is charac terized by involuntary muscle contraction in a non velocity dependent manner. In the majority of cases, an underlying cause remains unclear. The term describes a heterogenous set of conditions that can affect almost any location in the body, including the cervical musculature, oromandibular and laryngeal muscles, and the muscles of the extremities. The incidence is estimated at 24 per million per year [3] and occurs most commonly in men [4]. The incidence of upper extremity focal dystonia appears to be much higher in professionals who perform skilled tasks with their hands, such as musicians, dentists, surgeons, and watchmakers. CASE PRESENTATION An 81 year old man was referred to our rehabilitation clinic with a chief concern of severe right hallux varus deformity and an associated abnormal gait pattern. He first noticed this 15 years before presentation and acknowledged its progression over time. He also had right medial knee pain with ambulation. The patient had a pair of custom shoes with an oversized medial aspect of the toe box to accommodate his toe deformity. Other than these custom shoes, he had not undergone any other treatment. He denied any history of stroke or upper motor neuron disorder. There was no history of traumatic foot or toe injury. Medical and surgical histories were negative for foot trauma or surgery, contralateral joint deformity, or movement disorder. Pertinent family history was a daughter with a similar deformity. Physical examination demonstrated a right hallux varus with an abduction angle of 58 � when sitting (Figure 1) and firm muscular resistance appreciated with slow passive adduction of the great toe. This deformity was accentuated when standing, with a relative increase in abduction angle. There was no dystonia appreciated in the foot or the ankle. Neurologic examination was otherwise normal. Gait with a single point cane in the left hand was wide based, with pronounced external rotation of the right foot. A radiograph of the foot demonstrated medial subluxation of the first proximal phalanx with respect to the first metatarsal head. Given the physical examination finding of firm muscular resistance with slow passive adduction, electromyography (EMG) assessment of the right abductor hallucis was performed. The EMG demonstrated abnormal involuntary dystonic activity (Figure 2). This was presumed to be the cause of the patient’s great toe deformity. Botu linum toxin injection is indicated to reduce dystonic activity at this muscle [5]. After
Quantum affine algebras and holonomic difference equations

We derive new holonomicq-difference equations for the matrix coefficients of the products of intertwining operators for quantum affine algebra representations of levelk. We study the connection opertors between the solutions with different asymptotics and show that they are given by products of elliptic theta functions. We prove that the connection operators automatically provide elliptic solutions of Yang-Baxter equations in the “face” formulation for any type of Lie algebra $$\mathfrak{g}$$ and arbitrary finite-dimensional representations of . We conjecture that these solutions of the Yang-Baxter equations cover all elliptic solutions known in the contexts of IRF models of statistical mechanics. We also conjecture that in a special limit whenq→1 these solutions degenerate again into solutions with $$q' = \exp \left( {\frac{{2\pi i}}{{k + g}}} \right)$$ . We also study the simples examples of solutions of our holonomic difference equations associated to $$U_q (\widehat{\mathfrak{s}\mathfrak{l}(2)})$$ and find their expressions in terms of basic (orq−)-hypergeometric series. In the special case of spin −1/2 representations, we demonstrate that the connection matrix yields a famous Baxter solution of the Yang-Baxter equation corresponding to the solid-on-solid model of statistical mechanics.
Person-Centered and Variable-Centered Approaches to Longitudinal Data

As the number and scope of longitudinal investigations have expanded, so too have strategies for analyzing prospective data. Different analytic techniques are designed to answer different types of research questions. Person-centered approaches identify groups of individuals who share particular attributes or rela- tions among attributes. They are well suited for addressing questions that concern group differences in patterns of development. Variable-centered approaches describe associations between variables. They are well suited for addressing questions that concern the relative contributions that predictor variables make to an outcome. This special issue includes conceptual essays and empirical reports designed to demonstrate the complementary strengths of these two different approaches. The articles illustrate how the integration of person-oriented and variable-oriented approaches can lead to a more complete understanding of the processes and patterns of human development.
Cystic fibrosis in premature infants

There are few reports of cystic fibrosis (CF) diagnosed in premature infants. We describe the clinical course of three patients, from our neonatal intensive care units, who were diagnosed with CF, and discuss the existing literature and treatment considerations.
Chaos, perfectionism, and sabotage: personality disorders in the workplace.

Psychiatric nurses work in a variety of settings as supervisors, administrators, and consultants. They understand that success or failure of organizational activities depends in large measure on the staff's productivity, commitment, and cooperation. When these qualities are absent, major problems can ensue. This paper uses a case study approach to examine the impact that employees with borderline, obsessive-compulsive, and passive-aggressive personality disorders have on organizations. Specific disruptive behaviors that can challenge co-workers and negatively affect the effectiveness of the work group are presented. Therapeutic strategies are identified that have been adapted for use in the workplace. These strategies are used to help employees perform in a more effective manner while minimizing maladaptive responses to guidance and supervision.
Geometry-based spatial acoustic source location for spaced structures

This study presents a new source localization methodology to identify the spatial location of active flaws on spaced structures using the acoustic emission (AE) method. The methodology uses the geometric boundaries and the local coordinate system to find the shortest direct paths from the acoustic source to the AE sensors. The structural elements are modeled as 1D so that the source location is determined using linear equations in the local coordinate system. The local source location is converted into the global coordinate system to determine the source location in space. The approach has been successfully demonstrated using computer and laboratory simulations. The use of linear equations to solve the spatial location of the acoustic source in multi-dimensional space reduces the computational load as compared to the conventional 2D and 3D location algorithms.
Framework Surgery for Treatment of Unilateral Vocal Fold Paralysis

Laryngeal framework surgery is the current gold standard treatment for unilateral vocal fold paralysis (UVFP). It provides a permanent solution to glottic insufficiency caused by injury to the recurrent laryngeal nerve. Various modifications to the original Isshiki type I laryngoplasty procedure have been described to improve voice and swallowing outcomes. The success of this procedure is highly dependent on the experience of the surgeon as it epitomizes the intersection of art and science in the field. The following article reviews the evidence, controversies, and complications related to laryngoplasty for UVFP. It also provides a detailed analysis of how and when arytenoid-positioning procedures should be considered and summarizes the literature on postoperative outcomes.
A direct digital synthesis based chirp radar transmitter in 0.13 µm SiGe technology

This paper presents an X-band direct digital synthesis (DDS) based chirp radar transmitter implemented in 0.13μm SiGe BiCMOS technology. The transmitter contains a quadrature DDS, two low-pass filters, an IF IQ modulator, a programmable gain amplifier (PGA), a RF mixer and a pre-amplifier. The DDSs, built with two digital-to-analog converters (DACs), generate two-channel IQ baseband chirp signals from 62MHz to 77MHz. The IQ chirp signals are filtered by two programmable 5th-order Butterworth filters before up-converted to the IF frequency with IQ modulators. The filtered IF signal is further up-converted to the desired radio frequency by an RF mixer. The proposed transmitter thus generates a chirp signal at 8.6GHz, consuming a total power of 333 mW from 2.2V and 1.5V power supplies.
Propagation delay optimisation in multistage GaAs M.E.S.F.E.T. combinational logic circuits by use of dynamic programming

Propagation delays in multistage combinational logic circuits using GaAs metal-semiconductor field-effect transistors (m.e.s.f.e.t.s) are optimised subject to constraints on the overall power dissipation. Specific optimisation criteria are derived for 1-stage, 2-stage, and 3-stage combinational logic circuits. The results are evaluated with parameters of an existing process.
Sid4: A secreted vertebrate immunoglobulin protein with roles in zebrafish embryogenesis

Abstract The small members of the immunoglobulin superfamily (IGSF) are a molecularly diverse group of proteins composed solely of immunoglobulin domains. They may be secreted or tethered to the cell mebrane via GPI linkages and are proposed to have important functions in vivo. However, very few small IGSFs have been functionally characterized. During an ongoing in situ hybridization analysis of expressed sequence tags in zebrafish we identified secreted immunoglobulin domain 4 ( sid4 ), a gene encoding a soluble vertebrate protein composed solely of four immunoglobulin domains. Throughout development, sid4 is expressed in regions of the embryo undergoing active cell division and migration. Functional analysis using morpholino antisense oligonucleotides demonstrates that timing of gene expression is normal in morphants, but these embryos are smaller and exhibit defects in epiboly and patterning of axial and prechordal mesoderm. Analyses of chordin , pax2 , krox20 , and dlx2 expression in morphants demonstrate that early brain patterning is normal but later organization of hindbrain neurons and development of cranial neural crest are perturbed. Levels of apoptosis in morphants were normal prior to 90% epiboly, but were elevated after 10 h post-fertilization (hpf). Apoptosis does not account for early patterning defects of axial mesoderm, but likely contributes to overall reduction in embryo size. Phylogenetic analysis demonstrates that Sid4 is strikingly similar to the fibronectin binding Ig domains of Perlecan/HSPG2. Overall, our data demonstrate a fundamental role for sid4 , possibly as a co-factor in extracellular matrix (ECM) interactions, in processes underlying tissue patterning and organogenesis in a vertebrate.
Investigation of an N‐Butyl‐N‐(2‐Nitroxyethyl)Nitramine (BuNENA) Process: Identification of Process Intermediates, By‐Products and Reaction Pathways

A process for N-butyl-N-(2-nitroxyethyl)nitramine (BuNENA) was investigated: Step 1 involves N-butyl-ethanolamine addition to 98% HNO3 to form a salt mixture; Step 2 is addition of acetic anhydride/acetyl chloride catalyst to the salt mixture. A number of potential intermediates, by-products, and decomposition products from this process were identified/synthesized for use as analytical standards. BuNENA process reaction pathways/mechanisms were elucidated, including the nature of the amine salt solution formed in Step 1. In addition, potential pathways that could account for by-product formation were elaborated. A study of the consumption of acetyl nitrate in Step 2 was undertaken to prevent its build-up.
Small-Cell Carcinoma in Association With a Mature Cystic Teratoma of the Ovary: A Case Report With Literature Review

Malignant transformation of mature cystic teratoma (MCT) is a rare event, occurring in 1% to 2% of cases. Small-cell carcinoma arising from an MCT is particularly rare, with only 3 other cases described in the English literature. We report a case of a 54-year-old para 1 female who was found to have advanced-stage small-cell carcinoma of the ovary in association with a MCT. The clinicopathological features, treatment regimen, and outcome of this patient were compared with the other cases described in the literature to evaluate the prognostic significance of this unusual subtype of ovarian cancer. Small-cell carcinoma of the ovary arising from a mature cystic teratoma is a rare form of ovarian cancer. It is usually of the pulmonary subtype and is treated with the same chemotherapeutic regimen as small-cell lung cancer. The prognostic significance of this unusual cancer subtype remains uncertain.
Effect of angiotensin converting enzyme inhibitor (lisinopril) on insulin sensitivity and sodium transport in mild hypertension.

The purpose of this study was to determine whether antihypertensive therapy with the angiotensin converting enzyme inhibitor lisinopril would alter cell Na+ transport kinetics, metabolic parameters associated with insulin resistance, or both in young adults with mild hypertension. Sixteen young adults (mean age 29 ± 4 years) were treated with placebo for 8 weeks, then with lisinopril for 12 weeks. Metabolic risk factors examined included plasma lipid levels, plasma insulin concentration during an oral glucose tolerance test, and insulin sensitivity determined by an euglycemic hyperinsulinemic clamp procedure. Red blood cells were assayed for Na+/H+ exchange, Na+/Li+ exchange, Na+-K+ pump activity, and Na+-K+-Cl− cotransport before and during treatment. Blood pressure decreased from 142 ± 4/98 ± 2 mm Hg before treatment to 131 ± 3/85 ± 1 mm Hg during lisinopril treatment (P
Nonparametric determination of reactivity distributions from isotopic transient kinetic data

Abstract This paper presents a new, rigorous approach for the nonparametric determination of catalytic reactivity distributions from in situ kinetic information obtained using steady-state isotopic transient kinetic analysis (SSITKA). The method is based on a constrained, standard Tikhonov regularization of Fredholm integral equations of the first kind. Results of the validation and application of this method for the analysis of synthetic and real (ruthenium-catalyzed CO hydrogenation) data are given. The method was compared to another nonparametric one that is based on an inverse Laplace transformation introduced by M. de Pontes, G. H. Yokomizo, and A. T. Bell (J. Catal.104, 147 (1987)) and was found to be less subjective and more exact, but computationally more demanding. For the new method, the effects of measurement noise and incorrect background selection on the recovery of reactivity distributions were also evaluated. It was shown that the new method could faithfully recover reactivity distributions even when reasonably small amounts of random noise were present. Similar recovery tests also showed that proper background selection would be critical for the determination of reliable reactivity spectra.
Extraction and speciation of arsenic in lacustrine sediments.

Abstract Arsenic was partially extracted with 4.O M hydrochloric acid, from samples collected at 25-cm intervals in a 350-cm column of sediment at Milltown Reservoir, Montana and from a 60-cm core of sediment collected at the Cheyenne River Embayment of Lake Oahe, South Dakota. The sediment in both reservoirs is highly contaminated with arsenic. The extracted arsenic was separated into As(III) and As(V) on acetate form Dowex 1-X8 ion-exchange resin with 0.12 M HCl eluent. Residual arsenic was sequentially extracted with KClO 3 and HCl. Arsenic was determined by graphite-furnace atomic-absorption spectrometry. The analytical results define oxidized and reduced zones in the sediment columns.
Effect of monovalent cation-induced telomeric DNA structure on the binding of Oxytricha telomeric protein

Oligonucleotides bearing 4 repeats of telomeric deoxyguanosine-rich sequence undergo a monovalent cation-induced transition to a folded conformation with G-G base pairs, modeled as a 'G-quartet' structure. We have now deduced the rates of folding and unfolding of d(TTTTGGGG)4, which has four repeats of the Oxytricha telomeric DNA sequence. The estimated average values of delta G for the folded form at 37 degrees C are -2.2 kcal/mol and -4.7 kcal/mol in 50 mM na+ and K+, respectively. The fully folded DNA is not recognized by the Oxytricha telomere-binding protein; the substrate for protein binding has properties consistent with its being partly or fully unfolded. In confirmation of this conclusion, prevention of DNA folding by methylation enables the protein to bind as rapidly in the presence of monovalent cations as in their absence. The slow unfolding (t1/2 = 4 hr and 18 hr at 37 degrees C in Na+ and K+, respectively) of the DNA suggests that such structures would be long-lived if they formed in vivo, unless they can be actively unfolded. The inability of the telomere-binding protein to bind the stable, folded form of the 4-repeat telomeric sequence is a problem that may be circumvented in vivo by avoiding four single-stranded repeats.
WE‐E‐L100J‐02: A Phantom Study of Contrast‐Enhanced Dual Energy Mammography (CEDEM)

Purpose: To optimize and study the effectiveness of CEDEM using simple breast‐equivalent phantoms in the experimental setting. Method and Materials: The experimental evaluation of CEDEM was performed using a dedicated cone‐bream breast CT scanner in our laboratory, with the system operating in stationary imaging mode. A series of physical phantoms approximating the anatomical complexity of the breast were fabricated. Polyethylene and water were used for the adipose and glandular aspects of the breast phantom, respectively, due to their similar x‐ray attenuation characteristics. Holes of various sizes were randomly drilled on the polyethylene slabs to create an “anatomical” noise pattern. Rectangular cells (cuvettes) filled with various iodine concentrations were placed in a polyethylene slab to maintain a homogeneous projected iodine thickness (mg/cm2). When imaged experimentally, the polyethylene slab with five cuvettes of various iodine concentrations was overlaid with a number of the slabs with pseudo‐anatomical noise distributions while immersed in a plastic container filled with water. Data were acquired at 55 kVp and 100 kVp (suggested by computer optimization) with additional elemental filters (0.1 – 0.3 mm copper filtration), and dual‐energy subtracted images were produced. Results: Preliminary results were acquired at 55 kVp and 100 kVp (0.3 mm additional copper filtration). The sensitivity to iodine contrast agent in the dual‐energy subtracted image (signal‐difference‐to‐noise ratio (SDNR) per mg/cm2) was evaluated and found to be linear with concentration. The influence of the breast phantom thickness, composition, and dose on contrast enhancement at different kVp combinations will be presented. Conclusion: The effectiveness of CEDEM with an anatomical‐complex phantom was evaluated. The results indicate that the dual‐energy subtracted image can enhance the iodine contrast agent with background anatomical structures. This approach may be useful for the evaluation of the kinetic curve in contrast enhanced breast imaging procedures.
Electron-stimulated desorption of O+ and OH+ from CO covered Rh(111)

Abstract The kinetic energy distributions and yield-time dependence of electronically desorbed O + have been examined from clean Rh(111) and CO covered Rh(111). For the clean Rh(111) surface, we observe up to three peaks in the electron-stimulated desorption (ESD) O + kinetic energy distributions dependent on the amount of CO adsorbed and the thermal history of the surface. The highest energy O + peak appears at ∼ 8.0 eV and is present in the kinetic energy spectra only when CO is adsorbed on the surface. The intermediate energy O + peak at ∼ 3.5 eV appears only after CO exposures greater than ∼ 1.0 L and requires extended electron irradiation. The lowest energy peak at ∼ 1.5 eV is present only after the sample has been annealed to T > 1200 K and can be seen regardless of whether the Rh(111) surface has been exposed to CO. The intensities of both low energy peaks were electron beam dose dependent, indicating that the surface states detected were most likely electron beam induced. The high energy O + kinetic energy distribution peak was apparently due to CO adsorbed in both atop and bridge adsorption sites. The low energy O + kinetic energy distribution peak is thought to be due to electron-stimulated dissociation of adsorbed CO, which is supported by the similar behavior observed for the OH + kinetic energy distributions. Finally, the lowest energy O + kinetic energy distribution peak, which was present only after cleaning and annealing the Rh(111) crystal, may have been due to the presence of residual oxygen left over following the cleaning procedure.
CD-ROM versus standard text-based model for gynecologic operative procedures: a randomized controlled trial

Abstract Objective: To compare CD-ROM use with the standard text-based model ( TeLinde’s ) in the teaching of common gynecologic operative procedures to residents in the field of obstetrics and gynecology. Methods: In a randomized controlled trial, first-, second- and third-year residents in an obstetrics and gynecology department were randomized to receive either a CD-ROM that contains digitally edited surgical photographs with surgical text or a copy of the chapter of TeLinde’s that correlates with the operative procedure performed. The resident either viewed the CD-ROM or read the text model the evening before the surgery and then filled out a questionnaire afterward. Operations included TAH/BSO, TVH/BSO, cold knife conization, anterior colporrhaphy, perineorrhaphy, and Burch retropubic urethropexy. Helpfulness with indications, pelvic anatomy, understanding of techniques/methods, learning the names and uses of surgical instruments, and completing dictation were assessed in a rating system of 0 (not helpful) to 7 (extremely helpful). Results: During the study period, six residents completed questionnaires in both groups (CD-ROM, text group). The mean differences in resident evaluation of the surgical indications were 2.67 (Mann-Whitney rank sum, P = 0.0022); pelvic anatomy, 3.0 (Mann-Whitney rank sum, P = 0.0065); surgical techniques, 1.83 (Mann-Whitney rank sum, P = 0.0082); knowledge and use of instruments, 3.0 (Mann-Whitney rank sum, P = 0.0022); aid in completing surgical dictations, 3.167 (Mann-Whitney rank sum, P = 0.0022); and overall usefulness: 2.33 (Mann-Whitney rank sum, P = 0.0022). Conclusion: One of the biggest complaints from junior residents has been the lack of good photographs in traditional surgical textbooks. The residents in this study felt that the photographs shown on the CD-ROM better aided their knowledge of the indications, techniques, and surgical anatomy of the aforementioned procedures. We believe that the CD-ROM medium is underused and that it could provide better resident education, especially if combined with the traditional surgical textbook.
THE FINE STRUCTURE OF ISOLATED CHROMOSOMES.

Interphase and metaphase chromosomes have been isolated by spreading unfixed cells on the Langmuir trough, followed by critical point drying. Both types of chromosomes prove to be made up of cylindrical fibers which average 250 A in diameter. Smaller 80 A fibers, interconnecting regions of the 250 A fibers, have sometimes been observed. Nucleoprotein extracts have also shown a similar fibrous composition when prepared by the same methods. Deoxyribonuclease digestion results in complete destruction of the fiber. It has been shown that current disagreement concerning dimensions and substructure may be due partly to a contamination artifact. Evidence for the identity of the fibers and a possible mechanism for the coiling of chromosomes are discussed.
A Convergence exponent for multidimensional continued-fraction algorithms

We study a convergence exponent α of multidimensional continued-fraction algorithms (MCFAs). We provide a dynamical systems interpretation for this exponent, then express a general relation for the exponent in terms of the Kolmogorov-Sinai (KS) entropy and smallest eigenvalue of the associated shift map. We consider the case of approximating two irrationals and demonstrate the numerical method for using the smallest eigenvalue and entropy to evaluate α for several MCFAs, including Jacobi-Perron and GMA (generalized mediant algorithm). On very general grounds, the bounds for this exponent (for two irrationals) are 1⩽α⩽3/2=1.5. The upper bound is attained for algorithms with best approximation properties. We find αGMA=1.387 and αJP=1.374, as well as the values for the KS entropy and Oseledec eigenvalues.
A Strong Law of Large Numbers for Iterated Functions of Independent Random Variables

We study sequences of random variables obtained by iterative procedures, which can be thought of as nonlinear generalizations of the arithmetic mean. We prove a strong law of large numbers for a class of such iterations. This gives rise to the concept of generalized expected value of a random variable, for which we prove an analog of the classical Jensen inequality. We give several applications to models arising in mathematical physics and other areas.
Characterization of Miscanthus giganteus Lignin Isolated by Ethanol Organosolv Process under Reflux Condition

Miscanthus giganteus lignin was extracted by an organosolv process under reflux conditions (4 h) with varying concentrations of ethanol (65%, 75%, 85%, 95%) and 0.2 M hydrochloric acid as catalyst. The resulting lignin was extensively characterized by size exclusion chromatography (SEC), Fourier-transform infrared spectroscopy (FTIR), gas chromatography–mass spectrometry (GC/MS), two-dimensional nuclear magnetic resonance spectroscopy (2D-NMR), and chemical analysis (residual sugars, Klason lignin, ash). The predominant linkage units present were β-O-4′ (82–84%), resinol (6–7%), and phenylcoumaran (10–11%). The 65% ethanol solvent system gave the lowest lignin yield (14% of starting biomass) compared to 29–32% of the other systems. Increasing ethanol concentration resulted in decreasing carbohydrate content of the lignins (3.6–1.1%), a higher solubility in tetrahydrofuran (THF), a slight reduction of the molecular weight (Mw 2.72–2.25 KDa), an increasing α-ethoxylation, and an increase in ethoxylated phen...
Inhibitors of human immunodeficiency virus-1 protease

We have shown that the interaction of pepstatin A with human immunodeficiency virus-1 protease (HIV-1 protease) can be characterized by a high-affinity mode (Ki = 478 ± 27 nM), resulting in pure competitive inhibition of the hydrolytic activity of HIV-1 protease toward the fluorogenic substrate. Binding of pepstatin in this mode induces a blue shift in the endogenous fluorescence arising from the tryptophan residues in HIV-1 protease. This shift is maximal in the presence of 10 μM pepstatin. Haloperidol, in contrast, interacts with HIV-1 protease with weaker affinity (Ki = 19 ± 1 μM) in a mode which results in pure noncompetitive inhibition of the hydrolytic activity of HIV-1 protease. Binding of haloperidol in this mode induces a red shift in the endogenous fluorescence arising from the tryptophan residues in HIV-1 protease. This shift is maximal in the presence of 200 μM haloperidol. Addition of both pepstatin and haloperidol at concentrations in the range of their Ki values results in additive inhibiti...
Post-125 Ma carbon storage associated with continent-continent collision

Tectonic fragments subjected to high-pressure metamorphism in the Alps contain up to 1 vol% each of dolomite and graphite, indicating that significant amounts of carbon-bearing sediment were transported to depths greater than 50 km during the Alpine orogeny. The absence of a Cretaceous-Tertiary volcanic arc on the overriding plate suggests that much of the subducted carbon remains at depth today. Averaged over the length of the Alpine chain and the estimated amount of subduction that occurred in the past 125 m.y., ∼10 16 kg of carbon was buried because of collision in the Alpine region. Additional consideration of the Himalayan chain suggests that more than 10 17 kg of carbon has been buried since 125 Ma by continent-continent collision. Transfer of this amount of carbon from atmospheric and sedimentary reservoirs into a deep-seated metamorphic reservoir may help explain the significant decrease in global surface temperature that occurred from 125 Ma to the present.
Analgesia and the blood-brain barrier transport system for Tyr-MIF-1/enkephalins: evidence for a dissociation.

The blood-brain barrier is capable of transporting peptides with anti-opiate (Tyr-MIF-1) and opiate (enkephalins) activity out of the central nervous system. The relationship of this transport system to the various actions of opiates remains unexplored. This study examined the relationship between the rate of transport and opiate-induced analgesia. Both restraint, a stress that provokes an opiate-mediated analgesia, and the administration of morphine (12 mg/kg, i.p.) each induced an inhibition in the rate of transport. Such inhibition exhibited specificity, since the saturable, brain to blood transport of iodide remained unaltered. However, it was possible to dissociate analgesia and inhibition of transport. The onset and peak of analgesia, as measured by tail-flick latency induced by morphine, preceded the onset and peak of the inhibition of transport. Naltrexone, which blocks opiate-mediated analgesia, also induced inhibition of transport without any significant effect on tail-flick latency. (-) Naloxone but not (+) naloxone also weakly inhibited transport. Deprivation of food and water, associated with analgesia possibly mediated by the opiate, beta-endorphin, which is not transported out of the brain by this system, did not alter transport. These results suggest that while inhibition of transport and analgesia may occur together, these events probably represent two separate aspects of the action of opiates, that may even be mediated by separate receptor sites or peptides in the opiate family.