cssi/SciSciGPT-SciSciNet huggingface dataset:
Photosynthesis and carbon storage between tides in a brown alga, Fucus vesiculosus

Intertidal macroalgae may spend a significant part of their lives in air. During photosynthesis in air, they encounter much lower concentrations of inorganic carbon than in seawater. Because they accumulate inorganic carbon from seawater, we investigated whether they similarly accumulate it from air. We measured photosynthesis in the intertidal species Fucus vesiculosus L. during 1990 and 1991 with a gas-phase O2 electrode or CO2-exchange apparatus in air and with a liquid-phase O2 electrode in seawater. Maximum rates were rapid and similar in air and seawater regardless of the method. Tissue from seawater could carry on photosynthesis in CO2-free air, indicating that carbon was stored in the tissue. After 2 h, this store was depleted and photosynthesis ceased. Supplying CO2 in air replenished the store. Under identical conditions, terrestrial C3 and C4 species showed no evidence of this store, but a CAM (crassulacean acid metabolism) species did. However, in contrast to the CAM behavior, F. vesiculosus did not store CO2 significantly in the dark. We found a small acid-releasable pool of carbon in the tissue that disappeared as photosynthesis depleted the carbon store. However, the pool was too small to account for the total carbon stored. While CO2 was being acquired or released from the store in the light, photosynthesis was not inhibited by 21% O2. These results indicate that there are two parallel paths for the supply of CO2 to photosynthesis. The first depends on inorganic carbon in seawater or in air and supports rapid photosynthesis. The second involves CO2 slowly released from an organic intermediate. The release protects CO2 fixation from the inhibitory effects of 21% O2. Photosynthesis in F. vesiculosus thus appears to be C3-like in its rapid fixation of CO2 from a small inorganic pool into phosphoglycerate. However, it is C4-like in its pre-fixation of carbon in an organic pool in the light, and is CAM-like in its ability to slowly use this pool as a sole source of CO2. The organic pool may serve to protect photosynthetic CO2 fixation against the inhibitory effects of O2 in air and in the boundary layer in seawater.
Multiscale modeling of solid rocket motors: Computational aerodynamics methods for quasi-steady burning

We consider the problem of efficiently computing the stable burnback of a solid rocket motor when the motor is in the quasi-steady burning regime of operation. When the motor is modeled as a cavity, filled with a compressible fluid with injection from the solid-propellant surface, the problem is a standard one in steady computational aerodynamics. For large rockets, the problem of quasi-steady solid rocket motor core flow is analogous to the steady aerodynamic flow past a large aircraft flying at speeds such that compressible flow effects must be included. One can adopt advanced time-integration strategies that have been applied to commercial or military aircraft to solid rocket motor grain burning to compute a series of steady flows as the grain burns back to near completion. The slow regression of the burning solid-propellant surface is analogous to the motion of control surfaces on the aircraft. With straightforward two-timing, multiscale asymptotic analysis we develop a reduced quasi-steady description of the quasi-steady burning that is extensible to three dimensions. We show how to integrate reduced equations for stable quasi-steady motor burning and use the multigrid method as a representative method to obtain the steady flows in the frozen configurations.
Modulation of differentiation and mineralization of marrow stromal cells cultured on biomimetic hydrogels modified with Arg-Gly-Asp containing peptides

We synthesized biomimetic hydrogels modified with an osteopontin-derived peptide (ODP) and used them as a substrate for in vitro culture of marrow stromal cells (MSCs) to investigate the effect of the biomimetic surface on differentiation of MSCs into osteoblasts. Proliferation and biological assays for 16 days proved that MSCs became differentiated into osteoblasts secreting osteogenic phenotypic markers such as alkaline phosphatase (ALP), osteopontin, and mineralized calcium. In addition, there was an additive effect of the cell-binding peptide on differentiation and mineralization of MSCs cultured in the presence of soluble osteogenic supplements in cell culture media. For example, calcium content at day 16 on peptide-modified hydrogels was significantly higher than on tissue culture polystyrene. Two general trends were observed: (1) proliferation of MSCs decreased as the amount of differentiation markers increased, and (2) higher peptide concentrations accelerated the differentiation of MSCs. On the hydrogel modified with ODP, ALP activity exhibited a maximum value of 36.7 +/- 4.2 pmol/cell/h at day 10 for the concentration of 2 micromol/g while the culture time needed for maximum ALP activity occurred on day 13 for the lower concentrations. On the same hydrogel, the calcium content at day 10 was 21.4 +/- 2.3 ng/cell for the peptide concentration of 2 micromol/g and 1.0 +/- 0.3 ng/cell for 1.0 micromol/g. We used Gly-Arg-Gly-Asp-Ser (GRGDS) for modification of the hydrogel as a comparison to the results with ODP. However, osteoblast development was not significantly affected by the nature of the binding peptide sequences. These results suggest that MSC function can be modulated by variation of the peptide concentration in biomimetic hydrogels used for scaffold-based bone tissue engineering.
Portfolios for Biology Teacher Assessment.

On a warm, May afternoon, Karen, the high school biology teacher, perched on a stool in the lab reviewing her portfolio. Five years ago her school district had decided to experiment with replacing the annual teacher evaluation by an administrator’s classroom visit with a one-on-one conference based on the teacher’s portfolio. During the first year of the experiment, all teacher evaluation had been suspended as the faculty, working alone, in grade level groups, in subject area groups and as a body of the whole, struggled to reach agreement on questions about portfolio development. The first question was, “Evidence of what?” Other questions were: what documents would provide this evidence; how many documents; what types of documents; and what would be done with the portfolio once it was developed. During the second year, all of the faculty members were busy collecting the documents to provide the evidence for their first portfolios. There had been many conversations among the science teachers about whether this lab was the right one to videotape to display a commitment to student-centered lab work or whether that test really captured ongoing student evaluation. Deeper collegial relationships began to develop as the faculty, focusing on portfolio development, shared their successes and concerns. The faculty wanted this experiment on teacher evaluation to work because the judgment about the quality of teaching would reside among the teachers. The process of portfolio development had become formalized in a very short time. Karen kept a file drawer of potential documents for evidence-lesson plans, tests, videotapes, student work samples. Attached to each document was a caption. In September she had identified her professional goals for the year and had rehearsed them as she collected and tagged documents. Last week she had assembled the documents that demonstrated her progress toward her goals and arranged them as evidence to tell her story. Yesterday she had met with the other science teachers on the faculty and discussed her portfolio presentation. Now she was reviewing the documents to be submitted in the portfolio. Her chair was writing a letter of attestation to include in the portfolio, which she would deliver to the principal on Friday afternoon. On Monday she and the principal would meet and discuss her portfolio, her ideas for next year’s goals, and her decision to advance to the rank of Master Teacher after next year.
On a family of distributions obtained by the transformation of the gamma distribution

The distribution of y=e -1where I is distributed as a gamma random variable is considered(Grassia. 1977). It is shown that this transformed Family of distributions covers a wide region in the (√β1,β2) plane. The moments of this Family of distributions are easily calculated. The fitting of data to this family of distributions is illustrated with a numerical example and the resulting fit is compared with the Johnson's SB distribution fit.
Some effects of adrenocorticotropic hormone in various hypo-ovarian states. II. Primary amenorrhea, surgical castration, and the menopause.

IN a previous communication (1) we described certain effects of ACTH administered to 13 women with secondary amenorrhea. The present report deals with 8 other patients studied at the same time—2 with primary amenorrhea, 2 who were in the menopause, and 4 who had been surgically castrated. The purpose of the experiments was to determine whether complete absence of ovarian function would alter the metabolic and clinical effects of ACTH, as compared with its effects in women with partial ovarian failure. The methods of study were identical with those described for the first 13 cases. Table 1 gives the scheme of numbering of the patients, as well as certain essential clinical data, for the 8 subjects of this study. Detailed protocols for 5 of the 8 patients follow: Case 14. Mrs. D. E. was a 33-year-old white married woman. She had never had a spontaneous normal menstrual period. Pubic and axillary hair appeared at the age of 14-15 years, and the breasts began to develop at about the same time. Treatment with ...
Future distribution of tundra refugia in northern Alaska

Communities of boreal species are spreading northwards as tundra communities recede under climate change in the Arctic. Concurrently, human activities in the Arctic are increasing. This study takes a multidisclinary approach to investigate the potential future distribution of tundra species and to relate the location of refugial areas to disparate land-use practices in northern Alaska.
An integrated approach to emotional speech and gesture synthesis in humanoid robots

This paper describes an integrated approach to recognizing and generating affect on a humanoid robot as it interacts with a human user. We describe a method for detecting basic affect signals in the user's speech input and generate appropriately chosen responses on our robot platform. Responses are selected both in terms of content and emotional quality of the voice. Additionally, we synthesize gestures and facial expressions on the robot that magnify the effect of the conveyed emotional state of the robot. The guiding principle of our work is that adding the ability to detect and display emotion to physical agents allows their effective use in novel application areas such as child and elderly care, healthcare, education, and beyond.
Occult radiological effects of lipomatosis of the lumbosacral plexus

Objective Lipomatosis of nerve (LN) is a condition of massive peripheral nerve enlargement frequently associated with hypertrophy within the distribution of the nerve, and most commonly affecting the distal limbs. We sought to understand if LN of the lumbosacral plexus would be associated with the trophic effects of LN on surrounding tissue within the pelvis, which may be clinically occult, but present on MRI.
X-Band EPR Studies of Ferroelectric Lead Titanate (PT), Piezoelectric Lead Magnesium Niobate (PMN), and PMN/PT Powders at 10 and 85 K

X-band EPR spectra of lead titanate (PT) and lead magnesium niobate (PMN) powders prepared by different synthetic methods and a PMN/PT powder of the composition 0.9 PMN/01 PT were obtained at 85 and 10 K. Several EPR signals due to adventitious Fe{sup 3+} ion impurities, a signal due to the Ti{sup 3+} ion, and a signal due to the Pb{sup 3+} ion are observed for PT, PMN, and PMN/PT powders. The EPR signals observed at g = 2.0 and 6.0 are assigned to Fe{sup 3+} ions in the B-sites of the perovskite lattice structure of lad titanate with axial symmetry. The EPR signals observed at g = 1.99 and 4.25 are assigned to Fe{sup 3+} ions in the B-sites of the perovskite lattice structure of PMN and 0.9 PMN/0.1 PT materials with cubic and rhombic symmetries, respectively. The sharp EPR signal observed at g = 1.94 is assigned to Ti{sup 3=} ion for PT and 0.9 PMN/0.1 PT powders. In addition, a broader EPR signal at g = 2.28--2.30 for PMN obtained by the molten salt method is assigned to axial Pb{sup 3+} ion sites in this PMN material. EPR results obtained here for the e{sup 3+} ions in themore » B-sites of the PMN materials, in particular, suggest that both cubic and rhombic symmetry sites corresponding to a range of Nb(OMg){sub x}(ONb){sub 6{minus}x} site configurations exist in the PMN. These EPR results indicate that PMN likely exists with partial B-site cation (Mg/Nb) ordering in the perovskite lattice structure.« less
Life Change During Middle Adulthood and Valuing Leisure

(1989). Life Change During Middle Adulthood and Valuing Leisure. World Leisure & Recreation: Vol. 31, No. 1, pp. 29-31.
Overview of Monte Carlo radiation transport codes

Abstract The Radiation Safety Information Computational Center (RSICC) is the designated central repository of the United States Department of Energy (DOE) for nuclear software in radiation transport, safety, and shielding. Since the center was established in the early 60’s, there have been several Monte Carlo (MC) particle transport computer codes contributed by scientists from various countries. An overview of the neutron transport computer codes in the RSICC collection is presented.
Radiofrequency ablation therapy in concealed left free wall accessory pathway with decremental conduction.

An electrophysiologic study followed by transcatheter radiofrequency ablation therapy was performed in two adult patients with a permanent form of junctional tachycardia. Both patients had no structural heart disease and exhibited a normal resting ECG. The P wave during tachycardia was negative in leads 1, 3, and a VF, biphasic over V 6 , and positive in V 1 and aVL in both patients, while the P-R/R-P interval ratio during tachycardia was 0.82 and 0.36, respectively, in both patients. Both patients displayed an eccentric atrial activation sequence with the earliest atrial activation occurring at the distal coronary sinus and a decremental retrograde conduction property during incremental ventricular pacing, suggesting the presence of a concealed slowly conducting left free wall accessory pathway. The tachycardia used the normal atrioventricular pathway for anterograde conduction and the concealed slow left accessory pathway for retrograde conduction. It was terminated following adenosine administration in both patients; termination of tachycardia was due to a block in the retrograde accessory pathway in one patient and due to a block in the atrioventricular node in the other patient. Radiofrequency ablation was performed by the retrograde transaortic approach. The radiofrequency current was delivered to the site of the earliest atrial activation during tachycardia at the ventricular aspect of the mitral annulus. The successful ablation site had a ventriculoatrial (VA) interval of 120 and 130 ms, respectively, and was located at the posterolateral and lateral aspects of the mitral annulus. Following ablation, there was no VA conduction; however, conduction through the normal atrioventricular pathway was noted during isoproterenol infusion in both patients. There was no induction of tachycardia. This study demonstrates that the permanent form of junctional tachycardia in adults can incorporate a concealed left free wall accessory pathway with a decremental property. Radiofrequency ablation therapy is effective and safe in this form of arrhythmia.
Widespread patterns of neuronal damage following systemic or intracerebral injections of kainic acid: a histological study.

The effect of systemic and intracerebral injections of kainic acid, a potent neuroexcitatory and neurotoxic analogue of glutamate, has been studied in the rat using a variety of light- and electron-microscopic techniques. Systemic injections of 12 mg/kg produce a high incidence of ‘wet dog shakes’ and convulsions; seizure activity is consistently associated with neuronal damage. The initial neuropathological reactions include dendritic and glial dilations in discrete areas of the neuropil; at this time and subsequently, affected neuronal somata either appear swollen and pale, or are shrunken with dark cytoplasm. In the most severely affected areas, the lesion progresses to severe disruption of the neuropil. A vvidespread pattern of damage is seen throughout the forebrain, which is relatively consistent from brain to brain and is characterized by the parallel degeneration of pairs or groups of structures with extensive axonal interconnections. The commonly affected areas include the olfactory cortex, amygdaloid complex, hippocampus, and related parts of the thalamus and neocortex. Intracerebral injections of 2–6 nmol produce extensive neuronal damage in distant structures, as well as at the injection site. The pattern of distant damage varies with the site of the injection and appears to reflect axonal connections between the affected areas near the injection and the distant areas of damage. For example, injections into the olfactory cortex tend to produce damage in the amygdala, the mediodorsal thalamic nucleus, and related areas of the frontal cortex, as well as in the olfactory cortex itself. Injections into the posterior part of the olfactory cortex which involve the entorhinal cortex tend to produce severe degeneration in field CA1 of the hippocampus, although field CA3 is more severely damaged following intraventricular, intrahippocampal or intrastriatal injections. These observations suggest that kainic acid may exert at least part of its toxic effects via axonal connections. Furthermore, the widespread damage induced by intracerebral injections indicates that caution must be exercised in the use of kainic acid to produce circumscribed lesions, and that careful histological evaluation of such lesions is required.
Important risk factors of allograft survival in cadaveric renal transplantation. A study of 426 patients.

Multiple risk factors contribute to the allograft survival of patients who have cadaveric renal transplantation. A retrospective review of 19 such factors in 426 patients identified race, DR match, B + DR match, number of transplants, and preservation time to have a significant influence. The parametric analysis confirmed the effect to be primarily in the early phase, i.e., first 6 months. All patients received cyclosporine with other methods of immunosuppression resulting in an overall 1-year graft survival rate of 66%. The overall 1-year graft survival rate in the white race was 73% and in the black race was 57% (p = 0.002). Allograft survival and DR match showed white recipients with a 1 DR match to have 75% survival at 1 year compared with 57% in the black patient (p = 0.009). If HLA B + DR match was considered, the white recipient allograft survival increased to 76%, 84%, and 88% for 1, 2, and 3 match kidneys by parametric analysis. Patients receiving first grafts had better graft survival (68%) than those undergoing retransplantation (58%) (p = 0.05). Organ preservation less than 12 hours influenced allograft survival with a 78% 1-year survival rate compared with 63% for kidneys with 12-18 hours of preservation. Despite the benefits of B + DR typing, short preservation time, and first transplants to the white recipient, the allograft survival in the black recipient remained uninfluenced by these parameters.
Effect of ECS on one-trial learning following continuous- and partial-reinforcement training

Thirty-two naive male albino rats were trained to leverpress for sucrose using a discrete trial procedure. Half of the Ss were trained on a continuous-reinforcement schedule (CRF) and the other half were trained on a fixed-ratio schedule (FR). Following acquisition, for half of the Ss in each group, a leverpress produced footshock followed by ECS. For the remaining Ss a leverpress produced footshock only. Results showed that suppression of the leverpress response due to footshock was reduced by the ECS, regardless of the acquisition reinforcement schedule. Results also showed that FR-trained Ss failed to show the partial-reinforcement effect in extinction.
Offshore gas intermediary companies in Eurasia

Gazprom's utilization of offshore registration – or the moving of money across national boundaries for reasons other than of direct business benefit – has resulted in the creation of a web of subsidiary companies with opaque leadership and financial arrangements. Some of these subsidiary companies operate as intermediaries in the natural gas trade among the former Soviet states. Given that the gas trade within Eurasia has a long history of fixed contracts that move gas through a network of pipelines, why were intermediaries created, and why register them offshore? Using a critical reading of stateness as a space for transnational networks, and supported by mind-mapping software, we analysed the structure and operations of offshore gas intermediary companies between Russia and Central Asia dating from the break-up of the Soviet Union. We conclude that there were several purposes for using intermediary gas companies, from navigating trade among the newly independent states, to asset stripping, monopolizing ...
Merkel cell carcinoma – description of five cases

Merkel cell carcinoma (MCC) is a rare but very aggressive skin cancer that derives from neuroendocrine cells of the skin. Merkel cell carcinoma morbidity has been continuously increasing for the last few years. Increasing reported incidence of MCC is probably connected with increasing occurrence of this kind of malignancy or with development of histological and immunohistochemical methods of sample examinations which have allowed for more precise diagnosis of skin tumor that might have previously not been accurately recognized. Merkel cell carcinoma develops as nodules early recognized as basocellular carcinoma, squamous cell carcinoma, amelanotic melanoma or skin lymphoma. Merkel cell carcinoma can be morphologically similar to skin metastasis as well as mild changes such as lipoma, cysts, fibroma or vessel changes. Accurate diagnosis is very important because it determines successful management and risk of progression of disease. We describe 5 patients with MCC who underwent surgical excision and then, after estimation of stage of disease, complementary treatment. Our observations prove that every tumor with MCC should be cut out with wide margins and regional lymphadenectomy or sentinel node biopsy is compulsory. After cutting out MCC involved-field radiotherapy is necessary and improves prognosis. Presence of metastases in lymphatic nodes is an indication for complementary chemotherapy.
A Simplified Method for Calculating the Crack-Tip Field of Functionally Graded Materials Using the Domain Integral

A finite element based method is proposed for calculating stress intensity factors of functionally graded materials (FGMs). We show that the standard domain integral is sufficiently accurate when applied to FGMs; the nonhomogeneous term in the domain integral for nonhomogeneous materials is very small compared to the first term (the standard domain integral). In order to obtain it, the domain integral is evaluated around the crack tip using sufficiently fine mesh. We have estimated the error in neglecting the second term in terms of the radius of the domain for the domain integration, the material properties and their gradients. The advantage of the proposed method is that, besides its accuracy, it does not require the input of material gradients, derivatives of material properties; and existing finite element codes can be used for FGMs without much additional work. The numerical examples show that it is accurate and efficient. Also, a discussion on the fracture of the FGM interlayer structure is given.
Cure of Rickets by Water Soluble Extract of Yeast and Sodium Phosphate.

ConclusionIt is clear that the addition of sterol free, water soluble, extract of yeast plus secondary sodium phosphate to a rachitogenic diet caused the disappearance of the rachitic skeletal changes in rats.
Comments on "Fast Hardware Fourier Transformation Through Counting"

The Appendix of the above paper1 presents a serial sign flipper for radix (-2). Recently, a simpler realization has been brought to the attention of the author. The improved circuit has been developed independently of the published design by H. C. Wilck of the Jet Propulsion Laboratory, Pasadena, Calif. His approach to the problem is quite different from the author's.
Nepheline gabbro from the Mid-Atlantic Ridge.

IN the course of a long range programme aimed at the study of the petrology of the Equatorial Mid-Atlantic Ridge, a series of dredgings were made by Miami's Institute of Marine Sciences on the walls of the Romanche trench. The Romanche is a major tectonic fracture which intersects the Ridge close to the Equator, and offsets its axis, perpendicular to its elongation. At one locality on the north wall of the trench (station P6707-25; 00° 22′ S, 20° 09′ W) about 120 kg of rock fragments was recovered from 5,100–5,300 m below sea level. The dredged material consists of about 95 per cent (by weight) of basalt and glassy basaltic breccias; 2.5 per cent of gabbros; 2 per cent of cataclastic breccias; 0.5 per cent of serpentinized peridotite. Among the gabbros norites, troctolites and gabbros with alkali affinities were observed; among the latter, some contain modal nepheline and are similar to theralites. These alkali gabbros are of special interest, particularly because rocks with modal nepheline have not been reported in the past from oceanic ridges. We present here a description of them and a brief discussion of their origin.
Identification of the Minimal Copper(II)-Binding α-Synuclein Sequence

Parkinson’s disease has been long linked to environmental factors, such as transition metals and recently to α-synuclein, a presynaptic protein. Using tryptophan-containing peptides, we identified the minimal Cu(II)-binding sequence to be within the first four residues, MDV(F/W), anchored by the α-amino terminus. In addition, mutant peptide 1−10 (Lys → Arg) verified that neither Lys6 nor Lys10 are necessary for Cu(II) binding. Interestingly, Trp4 excited-state decay kinetics measured for peptides and proteins reveal two quenching modes, possibly arising from two distinct Cu(II)−polypeptide structures.
Dual citizenship as human right

Dual citizenship has become an unexceptional status in the wake of globalization yet remains at the sufferance of states. This essay advances the novel claim that dual citizenship should be protectable as a human right. In light of the threat that dual nationals once posed to stable bilateral relations, states were justified, historically, in suppressing the status. As that threat has dissipated, the values of freedom of association and liberal autonomy implied by citizenship ties should trump lingering state resistance. Failure to recognize the status also burdens the exercise of political rights by raising the cost of naturalization. Insofar as dual citizenship undermines state solidarities, that interest is too diffuse to justify nonapplication of associational and self-governance norms. There is growing evidence from state practice that dual citizenship is appropriately situated in a human rights framework.
Gigantecin: a novel antimitotic and cytotoxic acetogenin, with nonadjacent tetrahydrofuran rings, from Goniothalamus giganteus (Annonaceae).

Gigantecin (I), a novel tetrahydroxy-di-tetrahydrofuran fatty acid γ-lactone (acetogenin), was isolated from an ethanolic extract of the stem bark ofGoniothalamus giganteus Hook. f., Thomas (Annonaceae), by means of activity-directed fractionation (brine shrimp lethality test). This new compound is extremely cytotoxic to human tumor cells, inhibits crown gall tumors on potato discs, and is active in an assay designed to detect antimitotic agents (9 ASK).
Traumatic Brain Injury Among Newly Admitted Adolescents in the New York City Jail System

Abstract Purpose Relatively little is known about the prevalence of traumatic brain injury (TBI) among adolescents who come into contact with the criminal justice system. Methods We undertook screening for TBI among newly admitted adolescents in the New York City jail system using a validated TBI screening tool. A convenience sample of 300 male and 84 female screenings was examined. Results Screening revealed that 50% of male and 49% of female adolescents enter jail with a history of TBI. Incidence of TBI was assessed using patient health records, and revealed an incidence of 3,107 TBI per 100,000 person-years. Conclusions Elevated prevalence and incidence of TBI among incarcerated adolescents may relate to criminal justice involvement as well as friction in jail. Given the large representation of violence as a cause of TBI among our patients, we have begun focus groups with them to elicit meaningful strategies for living with and avoiding TBI.
Effects of Aging on the in Vitro Release of Gonadotropin-Releasing Hormone

Secretion of GnRH from mediobasal hypothalami (MBH) of old (23 month) and young (2 month) male rats was studied in an in vitro superfusion system. GnRH efflux from both old and young MBH increased in response to stimulation with 20 μm norepinephrine and 40 μm naloxone; however, both basal and stimulated GnRH release were reduced from MBH of old rats despite similar hypothalamic GnRH content. The diminished basal secretion and responsiveness to two major stimuli of the GnRH neuron may be important in the well-known involution of the hypothalamic-pituitary testicular axis in aging male rats. (Endocrinology 119: 1113–1117, 1986)
Testing the Notion of the One-Hit Exchange

Classical theory asserts that radiation-induced chromosomal exchanges result from the interaction of lesions on both chromosomes involved, a notion supported by substantial indirect evidence, but more recently questioned on biophysical and molecular grounds. When mitotic HeLa cells were irradiated with 60Co gamma rays, and fused together with Sendai virus, numerous chromosome exchanges were observed between the genomes of different cells at the next mitosis. However, when irradiated and unirradiated cells were fused together, the frequency of intergenomic exchange was 40-fold lower, suggesting that the vast majority of radiation-induced exchanges do, in fact, require damage to both chromosomes.
Sample path properties of stochastic processes represented as multiple stable integrals

Abstract This paper studies the sample path properties of stochastic processes represented by multiple symmetric α-stable integrals. It relates the “smoothness” of the sample paths to the “smoothness” of the (non-random) integrand. It also contains results about the behavior of the distribution of suprema and zero-one laws.
The role of montmorillonite in its catalysis of RNA synthesis

Abstract Montmorillonite catalyzes the oligomerization of activated nucleotides to form RNA. However, the mechanism of the montmorillonite catalysis, used as a model for similar prebiotic chemistry, is still not well understood. We have observed that the extent of catalysis depends not only upon the magnitude of the negative charge on the montmorillonite lattice and the number of cations associated with it, but also on the pH at which the reaction is promoted. The isotherm and catalysis studies have been extended to provide binding information and catalytic outcomes over a wide pH range. The optimal binding occurs in the region of maximal oligomer formation. X-ray diffraction studies revealed changes in layer separations of montmorillonite as reaction occurs. The application of the Scherrer equation to the X-ray diffraction data showed differences in domain size. Modeling of the size of the activated nucleotide monomers and the charge on the montmorillonite surface provided an interpretation of how these factors influence adsorption. This research provides a basis for further understanding of the physical processes in the mechanism of this catalysis.
Vibrational modes of A-DNA, B-DNA, and A-RNA backbones: an application of a green-function refinement procedure.

Normal vibrational analysis was carried out for DNA molecules in both A and B conformations as well as for A-RNA. A simplified backbone model was examined and expanded to include the backbone phosphate-group and the ribose ring. We applied the new force-constant refinement procedure discussed in the preceeding paper [Van Zandt, L. L., Lu, K.-C. & Prohofsky, E. W. (1977) Biopolymers, 16, 2481–90] to fit some observed frequencies in the Raman spectra for all three nucleic acids with the same set of force constants. The results indicate that the observed frequency shift can be attributed to the conformational change solely. We ignored the second-order differences in force constants for the different geometries. The agreement between the observed and calculated frequencies derived from the final refined set of force constants is good and apparently justifies this assumption. Two modes previously assigned to the symmetric diester O-P-O stretch and the symmetric dioxy O‥P‥O stretch are actually fitted. They are mainly backbone phosphate-group modes. The refined ribose-ring force-constants were transferred to the calculation of the vibrational spectrum of tetrahydrofuran. The overall agreement is again good. We discuss these calculations and the resulting normal modes. We also discuss the application of the Green-function refinement scheme and several strategies adopted to bias the convergence of the procedure.
Altered metabolism and mortality in patients with colon cancer receiving chemotherapy.

To identify the metabolic effects of 5-fluorouracil and hydrazine sulfate therapy, 22 patients with colon cancer were admitted prospectively to a Clinical Research Center for serial measurement of counter-regulatory hormones, fasting hepatic glucose production (HGP), intravenous glucose tolerance test, plasma leucine appearance (LA) and leucine oxidation. Combined therapy was associated with a significant reduction in fasting glucose level (98 ± 2 mg/dL to 94 ± 2, P 0.05). The decreased fasting glucose value was associated with a mild but not statistically improved glucose disposal rate in response to the intravenous glucose tolerance test (1.34 ± 0.07 %/min vs 1.47 ± 0.11, P = 0.15). Plasma leucine appearance was significantly reduced after 2 months of therapy (63.3 ± 3.0 μmol/kg/hr vs 57.1 ± 3.9 μmol/kg/hr; P < 0.025), but leucine oxidation (11.5 ± 1.1 μmol/kg/hr vs 11.2 ± 1.1 μmol/kg/hr) was not altered. Despite the fact that plasma triiodothyronine concentrations significantly increased with therapy, it was not associated with plasma LA. Half of the patients with cancer died 14 ± 4 months after the study, and the other half were alive 58 ± 2 months later. Survival time can be estimated with 59% accuracy using plasma LA, HGP, carcino-embryonic antigen, and insulin concentration. Multiple regression analysis identified that plasma LA was related directly to length of survival time, and baseline HGP, carcino-embryonic antigen, and insulin concentration were related inversely to length of survival. Unlike an elevated HGP seen in cancer cachexia, based on the association of a higher plasma LA and longer survival rate, an elevation in plasma LA may not be an unfavorable response to cancer. Further research is required to validate the predictability of baseline metabolic markers with survival rate in the cancer population.
A Substitute Name System in the Scottish Highlands

The high incidence of identical names among Gaelic speakers in East Sutherland leads to the use of “by-names” almost to the exclusion of official names. Several varieties of by-names are highly offensive. Appropriate use of the offensive varieties demands an intimate knowledge of the communities' social structure available only to their members; by-name misuse is consequently a source of social tension between Gaelic speakers and English speakers in the area. Nonetheless the practice of by-naming has spread to the English-speaking population, where the entertainment value of by-names takes precedence over their utilitarian value in distinguishing individuals bearing the same name. [Scotland; Gaelic, Celtic, names, sociolinguistics.]
Mechanism of dioxygen formation catalyzed by vanadium bromoperoxidase from Macrocystis pyrifera and Fucus distichus: steady state kinetic analysis and comparison to the mechanism of V-BrPO from Ascophyllum nodosum

Vanadium bromoperoxidase (V-BrPO) catalyzes the oxidation of bromide by hydrogen peroxide, which results in the bromation of appropriate organic substrates or the formation of dioxygen, in the absence of an organic substrate and under certain other conditions. The mechanism of the bromide-assisted disproportionation of hydrogen peroxide catalyzed by V-BrPO, which is the reaction that forms dioxygen, has been investigated for V-BrPO isolated from two new marine algal sources, Macrocystis pyrifera and Fucus distichus. The steady state kinetic studies have been performed under conditions of 0.02–40 mH H2O2, 1–500 mM Br− and pH 4.0–8.0. The rate data is consistent with a substrate-inhibited bi bi ping pong mechanism, in which the substrate bromide, is also an inhibitor by a noncompetitive-type mechanism. Bromide inhibits V-BrPO from M. pyrifera most strongly at pH 5.0–5.5 and V-BrPO from F. distichus most strongly at pH 5.5–6.0. The steady state mechanism of the Macrocystis and the Fucus enzymes are compared to the mechanism of the bromide-assisted disproportionation of hydrogen peroxide catalyzed by V-BrPO from Ascophyllum nodosum. In addition, the substrate hydrogen peroxide can also inhibit V-BrPO.
Characterization of Brucella canis protein antigens and polypeptide antibody responses of infected dogs

The cytoplasmic protein antigens (CPAg) of Brucella canis were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and analysis of 35S-labeled polypeptides. Approximate molecular weights of the immunoreactive polypeptides were determined by migration patterns of the immunoprecipitated polypeptides after SDS-PAGE or Western immunoblotting of sera collected at various times after experimental infection of dogs. Polypeptides were specifically precipitated by sera of infected dogs, but not from the sera of normal or false-positive (seropositive, non-infected) animals. During the initial month after infection, proteins with molecular weight masses (MW) of approximately 18, 22, 31, 42 and 54 kDa were commonly recognized. A 20-kDa polypeptide was first recognized at 8-10 weeks after infection, but it was detected inconsistently after 6 months. Additional polypeptides detected from 2 to 12 months post-infection had MW of 22, 66-68 and, less regularly, 42, 60, 82, 100 and greater than 200 kDa. The polypeptides most consistently recognized in sera from B. canis-infected dogs had MW of 18, 22 and 68 kDa.
Financial Attitudes and Inter vivos Resource Transfers from Older Parents to Adult Children

This exploratory study combines economic, family, and decision-making conceptual models to investigate the factors influencing resource transfers as reported by older adults. Pilot data on 61 adult children was obtained during face-to-face interviews with 18 older parents. Hierarchical multiple regressions were conducted to predict time (emotional support) and financial (cash and gifts) inter vivos transfers from demands, resources, values, and relationships. Positive health ratings, strong affection for the adult child, and money retention attitudes were associated with frequent emotional support. Small household size predicted frequent financial transfers. Results indicate the importance of values, resources, demands, and relationships in predicting resource transfers from older parent to adult child.
Surface grinding of space materials using specially formulated vitrified grinding wheels

The quantum leap that is expected in the reliability and safety of machined engineering components over the next 20 years, especially in the space industries, will require improvements in the quality of cutting tools if science-based manufacturing is the goal for manufacturing by 2020. Significant improvements have been made in the past 10 years by understanding the properties of vitrified bonding systems used to bond conventional and superabrasive materials in grinding tools. The nature of the bonding system is of paramount importance if next-generation cutting tools are to be used for aerospace materials, especially if they are dressed using laser beams.
Inhibition of Pneumococcal Adherence to Human Nasopharyngeal Epithelial Cells by Anti-PsaA Antibodies

The role of pneumococcal (Pnc) surface adhesin A (PsaA) in the adherence of Streptococcus pneumoniae (pneumococcus) to host cells is not well defined. We examined the effect of anti-PsaA antibodies in an inhibition of adherence assay using Detroit 562 nasopharyngeal human epithelial cells. Rabbit polyclonal (Pab) anti-recombinant PsaA (rPsaA) sera, a purified mouse monoclonal antibody (MAb) (MAb 6F62G8E12), and 22 healthy adult sera with known anti-PsaA IgG levels (obtained by enzyme-linked immunosorbent assay) were evaluated for their abilities to inhibit Pnc adherence to confluent monolayers (measured as percent reduction in CFU counts compared to those of uninhibited controls). Pnc adherence was dependent on capsular phenotype (no or low adherence for opaque strains). With an inoculum of 104 to 105 bacteria/well, the mean ± standard deviation count in controls was 163 ± 32 CFU/well for transparent strains. Low adherence was observed for a PsaA-minus mutant even at higher inoculum doses. Mean percent inhibitions of adherence with Pab and MAb were 54 and 50%, respectively. Adult sera showed inhibition in a dose-response fashion with a range of 98 to 8%, depending on the serum anti-PsaA antibody concentration. Absorption of Pab with rPsaA restored Pnc adherence to control levels. Absorption of sera with a PsaA-minus mutant did not result in a significant decrease (P >0.05) of inhibition of adherence activity. Additionally, nearly 100% of Pnc adherence was inhibited by lipidated rPsaA at 2.5 μg/ml. Our data support the argument that PsaA is an adhesin that mediates Pnc adherence to human nasopharyngeal cells. This functional assay may be useful in evaluating antibodies elicited in response to PsaA vaccination.
Interaction Model for Steel Compliant Riser on Soft Seabed

The use of catenary steel-compliant-riser (SCR) systems has increased as hydrocarbon production has moved progressively farther offshore and into deeper waters. The issue of fatigue damage caused by cyclic interaction of a riser with the seabed has gained prominence with the widespread use of SCRs and with the lengthening of the spans. The problem involves a number of complex factors, including trench configuration, nonlinear soil stiffness, breakaway of the riser from the seafloor, and degradation of soil resistance during cyclic loading. This paper presents a soilinteraction model capable of modeling these complexities, using input parameters that can be obtained with reasonable expenditure. Model simulations for typical offshore soft-soil conditions indicate that the model is capable of realistic predictions of cyclic bending moments. The degradation of soil resistance has a major effect on cyclic bending moments, particularly when uplift motions at the riser touchdown point (TDP) are large. © 2008 Society of Petroleum Engineers.
Full Configuration Drag Estimation

Accurate drag estimation is critical in making computational design studies. Drag may be estimated thousands of times during a multidisciplinary design optimization, and computational fluid dynamics is not yet possible in these studies. The current model has been developed as part of an air-vehicle conceptual-design multidisciplinary design optimization framework. Its use for subsonic and transonic aircraft configurations is presented and validated. We present our parametric geometry definition, followed by the drag model description. The drag model includes induced, friction, wave, and interference drag. The model is compared with subsonic and transonic isolated wings, and a wing/body configuration used previously in drag prediction workshops. The agreement between the predictions of the drag model and test data is good, but lessens at high lift coefficients and high transonic Mach numbers. In some cases the accuracy of this drag estimation method exceeds much more elaborate analyses.
T Lymphocyte–Endothelial Cell Interactions

Human vascular endothelial cells (EC) basally display class I and II MHC-peptide complexes on their surface and come in regular contact with circulating T cells. We propose that EC present microbial antigens to memory T cells as a mechanism of immune surveillance. Activated T cells, in turn, provide both soluble and contact-dependent signals to modulate normal EC functions, including formation and remodeling of blood vessels, regulation of blood flow, regulation of blood fluidity, maintenance of permselectivity, recruitment of inflammatory leukocytes, and antigen presentation leading to activation of T cells. T cell interactions with vascular EC are thus bidirectional and link the immune and circulatory systems.
A toxoplasma gondii-derived factor(s) stimulates immune downregulation : an in vitro model

Suppression of the T-cell lymphoproliferative response and downregulation of interleukin 2 (IL-2) production by Toxoplasma gondii has been observed following in vivo infection. In this study, an experimental in vitro murine system was developed to evaluate the kinetics of these responses. Normal splenocytes from uninfected mice were stimulated with either concanavalin A or an anti-CD3 monoclonal antibody and cocultured with Toxoplasma tachyzoites either directly or separated by a transwell. A progressive decline in the lymphoproliferative response was observed as the concentration of parasites in culture increased. Neither heat-killed nor formaldehyde-fixed parasites stimulated this downregulatory response by the splenocytes. A decline in IL-2 production was associated with the decrease in lymphocyte proliferation. The addition of an antibody to IL-10 or heat-inactivated anti-Toxoplasma sera to the culture supernatant partially neutralized the inhibitory effect on lymphocyte proliferation. Cytokine analysis of the responder splenocytes demonstrated a decrease in the message for IL-2 and IL-2 receptor and an increase in IL-10. Together, these observations suggest that during in vitro culture in a murine system, parasite antigens that stimulate the release of a soluble factor(s), such as IL-10, that inhibits proliferation of mitogen-stimulated T cells are expressed.
Pharmacogenomics of acute lymphoid leukemia: new insights into treatment toxicity and efficacy

Childhood acute lymphoblastic leukemia (ALL) provides an outstanding model for pharmacogenomic research: it is a drug-responsive disseminated cancer that is cured with medications alone in ∼ 85% of patients, but relapse remains unacceptably high for some subgroups. Inherited genomic variation contributes to the risk of relapse and to the risk of short- and long-term serious adverse effects of therapy. Our goal is to identify the inherited genomic variants that contribute to interindividual differences in response in patients with ALL. We discuss results of whole-genome interrogations of germline DNA in ALL.
Primary cutaneous Aspergillus ustus infection: Second reported case

Abstract We describe the second case of primary cutaneous Aspergillus ustus infection in an immunocompromised patient. Cutaneous aspergillosis was confirmed both by culture and positive fluorescent antibody staining. Few species of Aspergillus are pathogenic in human beings, and fewer still cause primary cutaneous disease. The only other reported case of aspergillosis from Aspergillus ustus occurred in an immunosuppressed patient who was temporally and geographically separated from ours. (J Am Acad Dermatol 1998;38:797-8.)