cssi/SciSciGPT-SciSciNet huggingface dataset:
A RADIOIMMUNOASSAY FOR THE DETECTION OF DELTA CRYSTALLIN IN CHICK LENS DIFFERENTIATION

Delta crystallin was isolated from 10–13 day chick embryo lens fiber cells. The lens fiber cell extract was isoelectrically precipitated at pH 5.1 to remove alpha and beta crystallins. Further purification by filtration through Sephadex G-150 and then acrylamide gel electrophoresis yielded a single, homogeneous preparation of delta crystallin, as characterized by gel electrophoresis. This purified delta crystallin was injected into rabbits to produce a potent antiserum to chick lens delta crystallin. The purified delta crystallin was iodinated with 125Iodine, using the chloramine-T procedure. A radioimmunoassay for delta crystallin was then developed, using the principles of competitive protein binding analysis. The radioimmunoassay developed here had a minimum sensitivity of 50 nanograms, and effectively ranged to 1000 nanograms. Developing lens rudiments from early chick embryos, beginning from 24 hr incubation up to 72 hr were examined at 6 hr intervals. All determinations from 24 hr through the 48 hr sample showed less than 10 nanograms per 100 lens rudiments. This was below the effective minimum detection limits of the assay. The first accumulation of delta crystallin was detected in the 54 hr sample, and increased thereafter.
Johachidolite, CaAl[B 3 O 7 ], a Borate with Very Dense Atomic Structure

JOHACHIDOLITE is a curious mineral species first described by Iwase and Saito1 from nepheline dikes cutting limestone at Johachido, North Korea. They proposed the unlikely formula H6Na2Ca3Al4F5B6O20 which prompted speculations in several subsequent papers, none of which reconciled its chemistry. Drs R. C. Erd and L. Aristarain have determined the cell parameters as being a, 7.970 ± 0.001; b, 11.722 ± 0.001; c, 4.374 ± 0.001 A, Cmma, Z=4 and they aroused our interest in the crystallographic structure.
Starch/Solute Interaction in Water Sorption as Affected by Pretreatment

The effect of the freeze-drying process on the structure of starch and starch-sucrose mixtures was studied. The technique of inverse gas chromatography was used to study the interaction between organic compounds (probes) and starch (hylon 7) as well as starch-sucrose mixtures. The structural and morphological characteristics of the starch-solute mixtures from the thermodynamic parameters of these interactions was also examined. The porous freeze-dried samples interacted more with certain organic probes compared with untreated starch as indicated by higher values of specific retention volumes (Vgo). Untreated starch apparently interacted only on the surface with organic probes. Freeze-dried starch reacted only with polar organic probes, particularly those with hydrogen bonding propensity. Cluster analysis of the water sorption isotherms correlated with data obtained from the injected probes.
The outer membrane usher forms a twin-pore secretion complex

The PapC usher is an outer membrane protein required for assembly and secretion of P pili in uropathogenic Escherichia coli. P pilus biogenesis occurs by the chaperone/usher pathway, a terminal branch of the general secretory pathway. Periplasmic chaperone-subunit complexes target to the PapC usher for fiber assembly and secretion through the usher to the cell surface. The molecular details of pilus biogenesis at the usher, and protein secretion across the outer membrane in general, are unclear. We studied the structure and oligomeric state of PapC by gel filtration, dynamic light scattering, and electron microscopy and image analysis. Two-dimensional crystals of wild-type PapC and a C-terminal deletion mutant of PapC were produced by reconstituting detergent purified usher into E.coli lipids. PapC formed a dimer both in detergent solution and in the phospholipid bilayer. Cryo-electron microscopy revealed that the usher forms a twin-pore complex. Removal of the C-terminal domain did not change the basic shape of the PapC molecule, but altered the dimeric association of the usher, suggesting that the C terminus forms part of the dimerization interface. The overall molecular size (11 nm), pore size (2 nm), and twin-pore configuration of PapC resemble that of the Tom40 complex, a mitochondrial outer membrane protein translocase.
The psychiatrist as moral advisor.

This paper is a critique of a paper by Robert Lipkin [1]. Arguments for the following claims are put forward: (1) that what is ‘essential’ to the psychiatric relationship is what we want it to be for utilitarian reasons; (2) it would not be to our advantage to allow the medicalization of morality; (3) what we should expect from the psychiatrist is prudential advice, not moral advice, and that Lipkin has a confused view about the relationship between these two areas; and (4) we should not allow the psychiatrist to restrict individuals on moral grounds, but only on public safety grounds.
Immune complex glomerulonephritis is induced in rats immunized with heterologous myeloperoxidase

Anti-neutrophil cytoplasmic antibodies (ANCA), including anti-myeloperoxidase (MPO) antibodies, are associated with pauci-immune necrotizing small vessel vasculitis or glomerulonephritis. In order to substantiate a pathogenic role for ANCA, an animal model of pauci-immune ANCA-induced glomerulonephritis or vasculitis is required. Brouwer et al. reported pauci-immune glomerulonephritis in rats immunized with human MPO followed by perfusion of kidneys with lysosomal enzyme extract combined with H2O2, and suggested that this could serve as a model of ANCA-induced disease. We repeated these studies in spontaneously hypertensive rats (SHR) and Brown Norway rats (BNR). We immunized rats with human MPO. When circulating anti-MPO antibodies were detectable by indirect immunofluorescence microscopy and ELISA, blood pressure was measured, then perfusion of the left kidney of each rat was done via the renal artery in a closed, blood-free circuit with either MPO + H2O2, MPO, H2O2 alone or MPO + H2O2 + neutral protease. Rats were killed on day 4 or day 10 after perfusion, and specimens were examined by light and immunofluorescence microscopy. Pathological lesions and deposits of IgG, C3, and MPO were found in immunized rats perfused with MPO + H2O2 with or without neutral protease, or MPO alone, in both rat strains and on both day 4 and day 10. The degree of histologic injury was proportional in intensity to the amount of IgG immune deposits. Spontaneously hypertensive rats sustained more damage and higher blood pressure than Brown Norway rats. No lesion was observed in immunized rats perfused with H2O2 or in the non-perfused right kidneys. Some of the non-immunized rats perfused with MPO + H2O2 developed pathological lesions. In conclusion, these rat models are examples of immune complex-mediated glomerulonephritis, and therefore are not similar to human ANCA-associated disease.
Evidence of interactions of organic sorbates with transition metal halides in gas—solid chromatography using thermodynamics and infrared studies

Abstract Investigations were conducted to study the separations obtained using anhydrous cobalt(II) and manganese(II) chlorides as gas chromatography packins and the extent to which their surface effects controlled or influenced these separations. Sorbates which varied in the degree of π-electron distribution, some having isolated π-bonds with varying electron density, were studied. Others consisted of conjugated π-electron systems (aryl systems). The order of elution of these compounds on both packins was correlated with the degree of π-electron distribution. Compounds with isolated π-bonds were retained more strongly than conjugated systems. Interaction appeared to be a function of π-electron density of the adsorbate and the electron deficient qualities of the transition metal salt. The thermodynamic functions Δ H , Δ S and Δ G were calculated by a computer program at temperatures of 50–150° and 29–60°. Heats of adsorption were less than 15 kcal/mole and entropies were in the range that could be predictted on the basis of vaporization, i.e. , no evidence of chemisorption could be demostrated thermodynamically in the chromatographic system. Non-chromatographic adsorption was studied by IR spectroscopy. Spectra obtained were identical for the same sorbate on either salt. Cobal(II) chloride appeared more selective than manganese(II) chloride despite the larger surface area of the latter.
Rapid thermal nitridation of thin SiO2 films

An alternative to SiO2 for gate dielectric applications in MIS devices is nitrided silicon dioxide. A study of this material is presented in this paper. Thin SiO2 layers (10 nm minimum thickness) were grown on silicon substrates and subsequently nitrided in ammonia at 1 atm using a rapid thermal processing system. Nitridation times ranged from 3 sec to 60 sec at temperatures from 900 to 1200‡ C. The resulting films were then characterized using a variety of techniques including high resolution TEM, XPS, AES, SIMS, and electrical measurements (C-V). Higher temperatures and longer processing times resulted in the accumulation of nitrogen at the film surface and at the Si/SiO2 interface. As expected, the electrical characteristics of the nitrided films were strongly influenced by the processing conditions. The morphology of the interface, as revealed by high-resolution TEM, was also altered by the nitridation process, especially for high processing temperatures (>1000° C).
Revised protocol for the kinematic assessment of impairment.

BACKGROUND CONTEXT: Marras et al. developed a functional motion performance tool that accurately identified impaired low back motion performance, with sensitivity of 90% and specificity of 94%. However, the protocol required testing of five controlled tasks and was relatively time consuming. PURPOSE: To determine whether a more time-efficient low back motion functional performance evaluation tool with acceptably high sensitivity and specificity could be developed. STUDY DESIGN/SETTING: Low back functional motion (kinematic) performance evaluations were completed on two groups, consisting of controls (no history of back pain) and low back pain patients. A second low back pain population was also evaluated prospectively to assess recovery. PATIENT SAMPLE: The study population consisted of 335 patients and 374 controls. Thirty acute low back pain patients were monitored prospectively. OUTCOME MEASURES: Kinematic low back functional performance measures. METHODS: Low back motion functional performance was measured using the lumbar motion monitor. A revised discriminant function model was developed using data from only one of the five original functional motion performance control tasks. Prospective study data were used to track differences in recovery time between the revised and original discriminant function models. RESULTS: The revised model using functional motion performance from the controlled sagittally symmetric task had a sensitivity of 90% and specificity of 92%. When comparing the revised and original model results, the time to recovery was the same in 90% of cases. CONCLUSIONS: The revised (more time efficient) testing procedure yielded high sensitivity and specificity. 2004 Elsevier Inc. All rights reserved.
Interactions between fission yeast Cdk9, its cyclin partner Pch1, and mRNA capping enzyme Pct1 suggest an elongation checkpoint for mRNA quality control.

RNA polymerase II (pol II) is subject to an early elongation delay induced by negative factors Spt5/Spt4 and NELF, which is overcome by the positive factor P-TEFb (Cdk9/cyclin T), a protein kinase that phosphorylates the pol II C-terminal domain (CTD) and the transcription elongation factor Spt5. Although the rationale for this arrest and restart is unclear, recent studies suggest a connection to mRNA capping, which is coupled to transcription elongation via physical and functional interactions between the cap-forming enzymes, the CTD-PO4, and Spt5. Here we identify a novel interaction between fission yeast RNA triphosphatase Pct1, the enzyme that initiates cap formation, andSchizosaccharomyces pombe Cdk9. The C-terminal segment of SpCdk9 comprises a Pct1-binding domain distinct from the N-terminal Cdk domain. We show that the Cdk domain interacts with S. pombePch1, a homolog of cyclin T, and that the purified recombinant SpCdk9/Pch1 heterodimer can phosphorylate both the pol II CTD and the C-terminal domain of S. pombe Spt5. We provide genetic evidence that SpCdk9 and Pch1 are functional orthologs of theSaccharomyces cerevisiae CTD kinase Bur1/Bur2, a putative yeast P-TEFb. Mutations of the kinase active site and the regulatory T-loop of SpCdk9 abolish its activity in vivo. Deleting the C-terminal domain of SpCdk9 causes a severe growth defect. We suggest a model whereby Spt5-induced arrest of early elongation ensures a temporal window for recruitment of the capping enzymes, which in turn attract Cdk9 to alleviate the arrest. This elongation checkpoint may avoid wasteful rounds of transcription of uncapped pre-mRNAs.
Comparison of VVIR, DDD, and DDDR Pacing

In the past several years there has been continued improvement in pacemaker technology, resulting in the availability of a large variety of pacemaker generators and pacing modes. The introduction of single-chamber rate modulated pacemakers provided a further improvement in pacing therapy. With the recent introduction of dual-chamber rate responsive pacemakers, it is now possible to more closely restore physiological function with pacing in a large number of patients. In deciding which pacing mode is most beneficial to a given patient, it is essential to understand the various characteristics of the different pacing modes that are available. It is essential to have knowledge of the underlying electrophysiological characteristics of the patient and how they would be affected by the different modes available. The VVIR mode will control bradycardia and provide rate adaptation but at the expense of AV synchrony. The DDD mode will control bradycardia and provide AV synchrony, but will not provide rate adaptation in patients with chronotropic incompetence. The DDDR mode will control bradycardia, maintain AV synchrony, and provide far rate adaptation in the presence of chronotropic incompetence. The chronotropic response to physiological stress and/or pacemaker syndrome are major determining factors in the choice of the best pacing mode. The primary goal of pacing therapy is to restore the heart function as close as possible to normal. When at all possible, this should include provision of both AV synchrony and rate modulation. The DDDR mode is preferable in most patients since it is capable of providing both AV synchrony and rate response (except those with chronic supraventricular arrhythmias). The VVIR mode is as effective in patients who have chronic atrial fibrillation or frequent episodes of supraventricitar arrhythmias.
Mindful Creativity Scale (MCS): Validation of a German version of the Langer Mindfulness Scale with patients with severe TBI and controls.

AbstractBackground: Mindfulness may have an impact on the recovery process in patients who have suffered severe traumatic brain injury (TBI). In order to make an instrument for measuring mindfulness within the German speaking clinical community available, a short, easily usable scale and a cross-cultural adaptation is needed.Objectives: To validate the Langer Mindfulness Scale (LMS) with German-speaking patients with severe TBI and their relatives (healthy controls).Research design: In a prospective cohort study of patients with severe TBI, test–re-test interviews were carried out at 6-month intervals.Sample: A total of 225 participants responded to the first survey and 230 completed the second survey.Measures: LMS, self-report questions on personality, openness and attention, as well as health and clinical evaluations (including cognitive and behavioural assessments).Results: On the basis of factor analysis, principal component analysis and item response analysis, the initial 21-items were reduced to six...
Toxicity of zinc and bleached kraft mill effluent to larval english sole ( Parophrys vetulus ) and topsmelt ( Atherinops affinis )

Toxicity test protocols were developed for larvae of two species of marine fishes of the Pacific coast of the United States. During winter months, larvae were obtained from adult English sole (Parophrys vetulus) spawned in the laboratory. Newly-hatched, nonfeeding larvae were used in 96-hr experiments to determine their acute sensitivity to inorganic and organic toxicants. Exposure to ZnSO(4) produced a 96-hr LC(50) of 14.5 mg Zn/L. A complex and variable organic effluent (untreated bleached kraft mill effluent; BKME) yielded 96-hr LC(50)s ranging from 1.2-9.3% BKME.Larvae were obtained from eggs collected from wild and laboratory populations of the spring and summer-spawning topsmelt (Atherinops affinis). Both acute (96-hr) mortality and longer-term (7-14 days) growth responses of topsmelt larvae to BKME were determined. Acute toxicity levels (96-hr LC(50)s) ranged from 6.2-9.7% BKME. No Observed Effect Levels (NOELs) for 7 and 14 day exposures ranged from 1.0-3.0% BKME.
EpCAM: Another Surface-to-Nucleus Missile

The epithelial-specific cell adhesion molecule (EpCAM) modulates cell adhesion and proliferation. Its overexpression correlates with tumor cell proliferation, and EpCAM is a therapeutic target. In the February issue of Nature Cell Biology , Maetzel et al. demonstrate that proliferative responses to EpCAM require regulated intramembrane proteolysis and a nucleocytoplasmic intracellular domain fragment.
Glass Transition Versus Microphase Separation: a Phenomenological Replica-Field Theory for AB Copolymer Systems

We present a phenomenological replica-field theory for symmetric AB copolymer systems with the A-block near its glass transition point. Using a variational principle based on the second Legendre transformation we prove that the interaction between composition fluctuations, due to the loss mobility of the A monomers, results in the elimination of microphase separation. Instead of a microphase separation there is a third-order phase transition between the homogeneous state and a glass-like state with broken replica symmetry of the two-replica density-density correlation function. We show that near the point of the glass transition two-replica correlation function Q αβ (q) is proportional to the square of the one-replica correlation function Q αβ G αα 2 (q), where Q αβ is a matrix describing the metric properties of the replica space. The phase diagram for this class of copolymer systems is calculated
Spatial and temporal variability of ribotyping results at a small watershed in South Carolina

The utility of library-based ribotyping methods for a very small study area was evaluated through comparison of local results to libraries with differing spatial and temporal scales. Ribotyping of Escherichia coli isolates was used to evaluate sources of fecal pollution at a coastal golf course in Beaufort County, South Carolina. Thirty-five E. coli isolates were obtained from water samples from a detention pond for testing against several local and regional libraries of known-source isolate patterns. A library of 92 E. coli ribotype patterns was created from wildlife feces obtained on the site. Additional libraries were available for comparison, including a library from Morgan Island, a small, geographically isolated area (including a monkey colony), and a library from ongoing statewide assessments. Seventeen (49%) of the unknown E. coli isolates matched isolates from raccoon and deer scat from the local library. Two isolates (6%) were matched with monkey sources from Morgan Island, and 13 (37%) were matched to raccoon, deer, and cows from the statewide assessment. Evaluation of repeated ribotyping analyses at the study area revealed evidence of temporal variability of potential sources in the local library. Only one of the isolates from the second year of fecal samples successfully matched with a fecal isolate from the previous year. The results from this study suggest that source identification results were variable both spatially and temporally, and that local, temporally specific libraries are most appropriate for library-based MST studies in small watersheds. Results also suggest that it will be difficult to employ adequate sample sizes to satisfactorily address unknown pattern variability.
Stochastic perturbation of dispersion-managed optical solitons

The stochastic perturbation of dispersion-managed optical solitons is studied in this paper, in addition to deterministic preturbation terms, by the aid of soliton perturbation theory. The super-Gaussian pulses are considered and the corresponding Langevin equations are derived and analyzed. It is shown that in presence of the perturbation terms, the soliton propagates down the fiber with a fixed mean energy.
The effect of physical interactions on melt-phase homogenization of mixtures of poly(m-xylene adipamide) with aliphatic polyamides induced by interchange reactions

Abstract Poly(m-xylene adipamide) (MXD6) was melt mixed at 290°C in a Brabender with the aliphatic polyamides: nylon-6,6, nylon-6,9, nylon-6,10, nylon-6,12 and nylon-12,12. MXD6 was found to be physically immiscible with each nylon-x,y; however, owing to interchange reactions during melt mixing, the mixtures eventually became one-phase. The time required for this reaction-induced phase homogenization was followed visually and by differential scanning calorimetry (loss of ability to crystallize and change in glass transition behaviour) and was found to increase significantly as the ratio of methylene to amide units, CH 2 NHCO ratio, in the aliphatic polyamide increased. The extent of reaction at the point of phase homogenization was determined by 1H nuclear magnetic resonance, and this, too, increased with the CH 2 NHCO ratio but not as much as the melt mixing time required for phase homogenization. These effects are attributed to the more unfavourable polymer-polymer interaction energy between MXD6 and nylon-x,y as the CH 2 NHCO ratio increases. This physical parameter is believed to influence the initial interfacial area (through the interfacial tension), the initial interfacial thickness and the length of the critical copolymer segment length for conversion of a microphase-separated block copolymer to a single-phase melt. All these factors influence the melt mixing time required for phase homogenization.
Calculation of retinal image quality for polychromatic light

Although the retinal image is typically polychromatic, few studies have examined polychromatic image quality in the human eye. We begin with a conceptual framework including the formulation of a psychophysical linking hypothesis that underlies the utility of image quality metrics based on the polychromatic point-spread function. We then outline strategies for computing polychromatic point-spread functions of the eye when monochromatic aberrations are known for only a single wavelength. Implementation problems and solutions for this strategy are described. Polychromatic image quality is largely unaffected by wavelength-dependent diffraction and higher-order chromatic aberration. However, accuracy is found to depend critically upon spectral sampling. Using typical aberrations from the Indiana Aberration Study, we assessed through-focus image quality for model eyes with and without chromatic aberrations using a polychromatic metric called the visual Strehl ratio. In the presence of typical levels of monochromatic aberrations, the effect of longitudinal chromatic aberration is greatly reduced. The effect of typical levels of transverse chromatic aberration is virtually eliminated in the presence of longitudinal chromatic aberration and monochromatic aberrations. Clinical value and limitations of the method are discussed.
Single-transverse-mode output from a fiber laser based on multimode interference

An alternative original approach to achieve single-transverse-mode laser emissions from multimode (MM) active fibers is demonstrated. The fiber cavity is constructed by simply splicing a conventional passive single-mode fiber (SMF-28) onto a few centimeters-long active MM fiber section whose length is precisely controlled. Owing to the self-imaging property of multimode interference (MMI) in the MM fiber, diffraction-limited laser output is obtained from the end of the SMF-28, and the MMI fiber laser is nearly as efficient as the corresponding MM fiber laser. Moreover, because of the spectral filtering effect during in-phase MMI, the bandwidth of the MMI fiber laser is below 0.5 nm.
Colonization, competition, and dispersal of pathogens in fluid flow networks

The colonization of bacteria in complex fluid flow networks, such as those found in host vasculature, remains poorly understood. Recently, it was reported that many bacteria, including Bacillus subtilis [1], Escherichia coli [2], and Pseudomonas aeruginosa [3, 4], can move in the opposite direction of fluid flow. Upstream movement results from the interplay between fluid shear stress and bacterial motility structures, and such rheotactic-like behavior is predicted to occur for a wide range of conditions [1]. Given the potential ubiquity of upstream movement, its impact on population-level behaviors within hosts could be significant. Here, we find that P. aeruginosa communities use a diverse set of motility strategies, including a novel surface-motility mechanism characterized by counter-advection and transverse diffusion, to rapidly disperse throughout vasculature-like flow networks. These motility modalities give P. aeruginosa a selective growth advantage, enabling it to self-segregate from other human pathogens such as Proteus mirabilis and Staphylococcus aureus that outcompete P. aeruginosa in well-mixed non-flow environments. We develop a quantitative model of bacterial colonization in flow networks, confirm our model in vivo in plant vasculature, and validate a key prediction that colonization and dispersal can be inhibited by modifying surface chemistry. Our results show that the interaction between flow mechanics and motility structures shapes the formation of mixed-species communities and suggest a general mechanism by which bacteria could colonize hosts. Furthermore, our results suggest novel strategies for tuning the composition of multi-species bacterial communities in hosts, preventing inappropriate colonization in medical devices, and combatting bacterial infections.
Performance of multiple cardiac biomarkers measured in the emergency department in patients with chronic kidney disease and chest pain.

Objective: To evaluate the individual components of a cardiac multimarker panel in the detection of acute myocardial infarction (AMI) in patients with chest pain across a spectrum of renal dysfunction. Methods: A total of 817 consecutive patients evaluated for a possible AMI in the emergency department (ED) enrolled in a prospective study of cardiac biomarkers assessed using a point-of-care device with myoglobin (MYO), cardiac troponin I (cTnI), and creatine kinase myocardial band (CK-MB), recorded at 0, 1.5, 3, and 9 hours. This study did not exclude patients on the basis of renal dysfunction. Baseline renal function was available in 808 patients. Patients were stratified by corrected creatinine clearance (CorrCrCl) into quartiles, and those on dialysis (n = 51) were considered as a fifth comparison group. Those patients with advanced renal dysfunction (CorrCrCl < 47/mL/min/72 kg) or on dialysis had higher rates of diabetes, hypertension, and prior coronary disease. Agreement for the diagnosis of AMI was required of two independent cardiologists using criteria based on history, electrocardiogram, and central laboratory assessment of serial cardiac markers. Results: More than 99% of all patients were admitted to a chest pain observation unit or the hospital. Mean MYO levels were elevated in the presence of renal dysfunction in those with and without myocardial infarction. Both MYO and CK-MB were correlated with CorrCrCl, (r = -0.36, p < 0.01, and r = -0.10, p = 0.01, respectively), while cTnI was not (r = -0.10, p = 0.12). Using multiple receiver operating characteristic curve testing, cTnI was found to be the most consistent marker across all strata of renal dysfunction, including end-stage renal disease on dialysis. The authors did not find a trend for false-positive cTnI and renal dysfunction. Conclusions: A point-of-care, rapid cardiac biomarker strategy utilizing cTnI is applicable and superior to MYO or CK-MB in the evaluation of chest pain in patients with renal dysfunction.
Cohen’s Rationalistic Naturalism

Morris Raphael Cohen was one of the most eminent figures in recent American philosophy. His critical mind, his erudition, his incisive expression, and his philosophic outlook made him a unique figure. His major work is Reason and Nature. Some of his other important books are The Meaning of History, Law and the Social Order and Preface to Logic. Cohen had a deep interest in the philosophy of science, in metaphysics, in social philosophy, in legal philosophy, and in the philosophy of history. His contribution to legal philosophy especially has been widely recognized. The present discussion of his philosophy will be limited to his general view of nature with some reference to his ethical theory.
Event power: how global events manage and manipulate, by Chris Rojek

Stuart Hall (1990) once noted that, in serious, critical intellectual work, there are no “absolute beginnings” and few unbroken continuities…[and] it is because of this complex articulation between...
Load biaxiality and fracture: A two-sided history of complementing errors

Abstract It is the view of many engineers associated with fracture mechanics, materials science and mechanical design that for bodies containing plane cracks, loads that are applied in a direction that is parallel to the plane of the crack, in addition to the tensile load acting in the direction perpendicular to it, can have no influence upon the fracture behavior of the body. This point of view has persisted for the past sixty years or so, and still continues to persist, despite the paucity of experimental evidence in support of it. This paper traces the two-sided historical genesis of this notion. It shows how a series of oversights or errors, both in the calculation of the elastic strain energy appearing in Griffith's global crack instability hypothesis and in the evolution of Irwin's local theory of the crack-tip elastic stress intensity, have, by coincidence, had the particular effect of nullifying the presence of the loads that are applied parallel to the crack. The mishaps associated with one theory are, in a sense, complimentary to the entirely different set of errors that cause this same null effect to appear in the other theory, in that they give the appearance of consistency between the two theories in this regard. In a subsequent paper, which will serve to synthesize the results of our research work in this area, considerable experimental data will be included that lends support to our contention that loads that are applied parallel to the plane of the crack have a decided influence upon the fracture behavior of the body.
Induction of mutations by chemical agents at the hypoxanthine-guanine phosphoribosyl transferase locus in human epithelial teratoma cells.

Abstract Induction of 6-thioguanine (TG) resistance by chemical mutagens was examined in a line of cells derived from a human epithelial teratocarcinoma cell clone. The cells, designated as P3 cells, have a stable diploid karyotype with 46(XX) chromosomes, including a translocation between chromosomes 15 and 20. Efficient recovery of TG-resistant mutants induced by the direct-acting mutagens: N -methyl- N ′-nitro- N -nitrosoguanidine (MNNG); 7 β ,8 α -dihydroxy-9 α ,10 α -epoxy-7,8,9,10-tetrahydrobenzo[ a ]pyrene (BPDE); and benzo[ a ]pyrene (B[ a ]P); activated in a cell-mediated assay, required an expression time of 7 days and a saturation density of 2 × 10 4 cells/60-mm petri dish. The TG-resistant mutant cells induced by MNNG and BPDE maintained their resistant phenotype 4–6 weeks after isolation. This mutant phenotype was associated with a more than 10-fold reduction in hypoxanthine-guanine phosphoribosyl transferase (HGPRT) activity relative to that of the parental P3 cell line, which was shown to catalyze the formation of 4.6 pmoles inosine-5′-monophosphate (IMP)/min/μg protein. Induction of TG resistance was also observed in P3 cells cocultivated in a cell-mediated assay with human breast carcinoma cells, which are capable of polyclinic aromatic hydrocarbon (PAH) metabolism, after treatment with the carcinogenic PAHs: B[ a ]P, chrysene, 7,12-dimethylbenz[ a ]anthracene (DMBA), and 3-methylcholanthrene (MCA). The degree of mutant induction in this assay was related to the carcinogenic potency of these PAHs in experimental animals. The most potent mutagen was DMBA, followed in decreasing order by MCA, B[ a ]P, and chrysene. DMBA, at 0.4 μM, increased the frequency of mutants for TG resistance from 2 for the control to about 200 TG-resistant mutants/10 6 colony-forming cells (CFC). Benzo[ e ]pyrene (B[ e ]P) and pyrene, which are not carcinogenic, were not effective in the assay. None of the PAHs was mutagenic in the P3 cells cultivated in the absence of the PAH-metabolizing cells. These results indicate that the P3 cells can be useful for the study of mutagenesis at the HGPRT locus by direct-acting chemical mutagens, as well as by chemicals activated in a cell-mediated assay.
The National Football League Player Draft: Does It Equalize Team Strengths?

The teams in the National Football League are bound by a set of agreements that restrict the competition and divide the market for playing talent. This article analyzes one of these agreements: the draft, its effects on player salaries, the League's justifications for it, and its impact on team performances. There is evidence to suggest that the amateur player draft system has a restrictive effect on player salaries. Yet, the owners have argued that the draft helps equalize team strengths and is therefore essential to the League's financial well-being. The statistical study described in this article attempted to determine the relationship between a team's priority position in the draft and its change in performance in subsequent years. The actual correlations between these two variables, although statistically significant, were rather low and, thus, undermine the League's arguments.
Understanding prescription adherence: pharmacy claims data from the Contraceptive CHOICE Project.

BACKGROUND: We examined prescription adherence rates by contraceptive method among women who used oral contraceptive pills (OCP) transdermal patch or vaginal ring. STUDY DESIGN: Women in the St. Louis area were provided their choice of OCP patch or ring at no cost and followed for 18 months. Time between monthly refills was obtained from pharmacy data and analyzed as a marker of adherence. Risk factors for initial nonadherence were estimated using Cox proportional hazards; predictors for repeated nonadherence were analyzed using Poisson regression with robust error variance. RESULTS: Overall 619 participants filled 6435 contraceptive prescriptions with a median of 10 refills per participant. Only 30% of women (n = 187) obtained all refills on time. In the time-to-failure analysis use of vaginal ring and increased parity were predictors of early nonadherence (p < .05). In the multivariable analysis use of the vaginal ring and history of abortion were risk factors for repeated nonadherence (p < .01). CONCLUSIONS: Even with financial barriers removed pharmacy data show that many women inconsistently refill their contraception and may be at risk for unintended pregnancy. Copyright (c) 2011 Elsevier Inc. All rights reserved.
Z-Shaped MEMS Thermal Actuators: Piezoresistive Self-Sensing and Preliminary Results for Feedback Control

Feedback control of microactuators holds potential to significantly improve their performance and reliability. A critical step to realize the feedback control of microactuators is feedback sensing. In this paper, we report the feasibility of using a Z-shaped thermal actuator (ZTA) as a simultaneous force or displacement sensor. An in situ scanning electron microscope nanomanipulation process is used to characterize the piezoresistive response of ZTAs, which shows that ZTAs can be used as piezoresistive sensors. The experimental results agree very well with multiphysics (electric-thermal-structural-piezoresistive) simulations. A new feedback scheme is further explored, where the ZTA is treated as a two-input (applied current and external force) and two-output (displacement and electric resistance) system. Based on the calibrated relationships between the inputs and the outputs, a feedback system is developed, which can simultaneously sense the external force and generate updated current to actuate the ZTA to the desired position. We demonstrate preliminary results of this feedback control by holding the ZTA at a constant position under various external forces. The device and method presented in this paper are valuable for a range of microelectromechanical systems applications, including on-chip nanoscale mechanical testing and nanopositioning.
Uniform Electromagnetic Field in the Theory of General Relativity

A cosmological solution of the Einstein-Maxwell's field equations, corresponding to the case of a uniform (that is, covariant constant) electromagnetic field, is derived by means of simple geometrical arguments; the Riemannian manifold it corresponds to is the product of two ordinary surfaces of constant curvature, whose type and radius depend on the values of the cosmological constant and the invariants of the electromagnetic field. The world-lines of charged test particles have also a very simple geometrical meaning.
Risk and Cooperation: Managing Hazardous Fuel in Mixed Ownership Landscapes

Managing natural processes at the landscape scale to promote forest health is important, especially in the case of wildfire, where the ability of a landowner to protect his or her individual parcel is constrained by conditions on neighboring ownerships. However, management at a landscape scale is also challenging because it requires cooperation on plans and actions that cross ownership boundaries. Cooperation depends on people’s beliefs and norms about reciprocity and perceptions of the risks and benefits of interacting with others. Using logistic regression tests on mail survey data and qualitative analysis of interviews with landowners, we examined the relationship between perceived wildfire risk and cooperation in the management of hazardous fuel by nonindustrial private forest (NIPF) owners in fire-prone landscapes of eastern Oregon. We found that NIPF owners who perceived a risk of wildfire to their properties, and perceived that conditions on nearby public forestlands contributed to this risk, were more likely to have cooperated with public agencies in the past to reduce fire risk than owners who did not perceive a risk of wildfire to their properties. Wildfire risk perception was not associated with past cooperation among NIPF owners. The greater social barriers to private–private cooperation than to private–public cooperation, and perceptions of more hazardous conditions on public compared with private forestlands may explain this difference. Owners expressed a strong willingness to cooperate with others in future cross-boundary efforts to reduce fire risk, however. We explore barriers to cooperative forest management across ownerships, and identify models of cooperation that hold potential for future collective action to reduce wildfire risk.
Landscapes of Struggle: Politics, Society, and Community in El Salvador

During the 1980s, El Salvador's violent civil war captured the world's attention. In the years since, the country has undergone dramatic changes. Landscapes of Struggle offers a broad, interdisciplinary assessment of El Salvador from the late nineteenth century to the present, focusing on the ways local politics have shaped the development of the nation. Proceeding chronologically, these essays - by historians, political scientists, sociologists, and anthropologists - explore the political, social, and cultural dynamics governing the Salvadoran experience, including the crucial roles of land, the military, and ethnicity; the effects of the civil war; and recent transformations, such as the growth of a large Salvadoran diaspora in the United States. Taken together, they provide a fully realized portrait of El Salvador's troublesome past, transformative present, and uncertain future.
Supervising Spoiled Selfhood: Inquiry and Interpretation in the History of Modern American Child Adoption

ABSTRACT This article uses child adoption to explore the science and the politics of selfhood in modern U.S. history, especially forms of spoiled selfhood associated with difference and deviance. In particular, it traces the debate about whether and how parents should inform children of their adoptive status. Why was “telling” both imperative and troublesome? What theories about normal and abnormal identity and belonging were implicated in the practice? The case of the adopted self suggests why child development and family life became the subjects of ambitious legal intervention, professional management, and research in the human sciences during the twentieth century. Normalization was a favored governmental activity that also exposed a central tension between liberalism, on the one hand, and conceptions of nature at odds with it, on the other.
Further note on the Hermite-Fujiwara theorem

The author requests a more precise indication of the link between this theorem and the Ralston (1962) symmetric matrix and Routh-Hurwitz determinants.
Abnormal breakdown of α2-macroglobulin-trypsin complex in cystic fibrosis

Abstract The complex of trypsin with purified α 2 -macroglobulin from normals and patients with cystic fibrosis was studied. The formed complex failed to reveal any proteolytic activity toward a high molecular weight substrate whereas the esterolytic activity towards a low molecular weight substrate was retained. This esterolytic activity was resistant to inhibition by a high molecular weight inhibitor. During incubation at 38° C the complex with normal α 2 -macroglobulin was slowly inhibited by the high molecular weight inhibitor and regained activity with the high molecular weight substrate. This phenomenon was not obtained when the α 2 -macroglobulin from cystic fibrosis was examined. These data suggest that the gradual conversion of normal α 2 -macroglobulin-trypsin complex into an α 2 -macroglobulin fragment-trypsin complex is deficient in patients with cystic fibrosis.
Feasibility of an uncooled imaging spectrometer for the exploration of the solar system

A state-of-the-art imaging spectrometer concept is presented for visible-midwavelength IR spectral region studies of the solar system that obviates the until-now essential use of cryogenic cooling. This uncooled imaging spectrometer configuration is evaluated in view of the prospective environments of the instrument in various spacecraft orbits, as well as in light of various available photodetector materials and sensor focal plane array configurations.
Changes in shape and composition of sea-salt particles upon aging in an urban atmosphere

Abstract Sea salt is one of the most abundant types of natural aerosol particles and significantly influences local and global climate. It is an important constituent of samples collected between June 10 and 15 in the Los Angeles area during the 2010 CalNex campaign. The sea-salt particles reacted with other species in the atmosphere and became Na-bearing aerosol (NaA) particles. Using transmission electron microscopy, we found that Na occurred in almost half of all analyzed particles (∼3500), although commonly only in minor amounts. Almost all the NaA particles contained S but not Cl, suggesting that Cl was depleted through particle formation to sulfate, nitrate, or both in the urban atmosphere. We observed both rounded and euhedral NaA particles. The rounded ones consisted mainly of aged sea salt (>12 h) that had reacted extensively with sulfate, whereas the euhedral ones occurred in samples from relatively fresh marine air. The shapes and compositions of NaA particles changed within 3 h in the urban atmosphere. Moreover, our calculations indicate that light scattering from NaA particles depends on their shapes (e.g., roughly spherical, flat, or elongated). These compositions and shapes affect hygroscopicities and light scattering, respectively, both of which influence their climate effects.
An adiabatic state approach to electronically nonadiabatic wave packet dynamics

In the present study we introduce a time-dependent wave packet method to treat electronically non-adiabatic processes explicitly in the coupled adiabatic state representation. The method is applied to the predissociation of the MgCl (A2II) state and is shown to be easy to implement, with the computational effort being comparable to the corresponding calculation in the diabatic basis. © 1992 John Wiley & Sons, Inc.
Osteopontin Is Expressed in Human Aortic Valvular Lesions

Background Nonrheumatic stenosis of trileaflet aortic valves, in which calcification is a prominent feature, has been termed a “degenerative” condition, but it has been demonstrated recently that chronic inflammation is a characteristic feature of the developing lesion of aortic stenosis. This observation raised the possibility that calcification in the aortic valve might be actively regulated. Thus, the present study investigated whether osteopontin, a protein implicated in the regulation of both normal and dystrophic calcification, could be detected in lesions of valvular aortic stenosis. Methods and Results Morphological and immunohistochemical studies were performed on 14 human aortic valves, representing a range of pathology from normal to clinically stenotic. The extent of calcification and macrophage accumulation and their relation to the presence of osteopontin protein were characterized. Highly statistically significant associations were found between the degree of osteopontin expression and the ...
Distribution of imported 14C in developing leaves of eastern cottonwood according to phyllotaxy

Individual leaves of eastern cottonwood (Populus deltoides Bartr.), representing an ontogenetic series from leaf plastochron index (LPI) 3.0 to 8.0, were fed 14CO2 and harvested after 2–24 h. Importing leaves from LPI-1.0 through 8.0 on each plant were sectioned into 9 parts, and each part was quantitatively assayed for 14C activity. The highest level of 14C import was by leaves from LPI 1.0 to 3.0, irrespective of source-leaf age. 14C was translocated preferentially to either the right or left lamina-half depending on the position of the importing leaf in the phyllotactic sequence and its stage of development. For example, import was high when the importing leaf and the source leaf had two vascular bundles in common, moderately high with one bundle in common, and low with no bundles in common. The distribution of 14C within young importing leaves was highest in the lamina tip and decreased toward the base. With increasing leaf age, incorporation declined in the lamina tip and increased in the base.