cssi/SciSciGPT-SciSciNet huggingface dataset:
An encyclopedia of mouse genes.

The laboratory mouse is the premier model system for studies of mammalian development due to the powerful classical genetic analysis1 possible (see also the Jackson Laboratory web site, http://www.jax.org/ ) and the ever–expanding collection of molecular tools2,3. To enhance the utility of the mouse system, we initiated a program to generate a large database of expressed sequence tags (ESTs) that can provide rapid access to genes4,5,6,7,8,9,10,11,12,13,14,15,16. Of particular significance was the possibility that cDNA libraries could be prepared from very early stages of development, a situation unrealized in human EST projects7,12. We report here the development of a comprehensive database of ESTs for the mouse. The project, initiated in March 1996, has focused on 5´ end sequences from directionally cloned, oligo–dT primed cDNA libraries. As of 23 October 1998, 352,040 sequences had been generated, annotated and deposited in dbEST, where they comprised 93% of the total ESTs available for mouse. EST data are versatile and have been applied to gene identification17, comparative sequence analysis18,19, comparative gene mapping and candidate disease gene identification20, genome sequence annotation21,22, microarray development23 and the development of gene–based map resources24.
Conversion of 5-iodo-2-pyrimidinone-2'-deoxyribose to 5-iodo-deoxyuridine by aldehyde oxidase. Implication in hepatotropic drug design.

Abstract 5-Iodo-2-pyrimidinone-2'-deoxyribose (IPdR) can be converted into 5-iodo-deoxyuridine (IUdR), a clinical radiosensitizer, by aldehyde oxidase in the liver. This conversion does not require exogenous cofactors and cannot be catalyzed by mixed-function oxidases, xanthine oxidase or many other oxido-reductases. This “IPdR oxidase” activity is enriched in the liver; thus, extensive conversion of IPdR to IUdR could be anticipated in the liver and the therapeutic index of IPdR could be better than that of IUdR as a radiosensitizer for primary liver cancers or tumors metastasized to the liver. Based on structure and activity relationship studies, nucleoside analogues which could be activated by this enzyme to compounds capable of inhibiting DNA synthesis could be designed and should be explored as agents against cancer, viruses or parasites in the liver.
Activation and Deactivation Rates in High-Power Lasers

A detailed knowledge of activation and deactivation rates for excited molecular states is essential for the design of molecular lasers and their development into efficient high-power devices. This is especially true when one is no longer dealing with the well-known infrared laser systems discussed by Dr. WILSON at this mee ti ng, but instead is attempting to devise new systems, based perhaps on molecular electronic transitions in the visible or ultraviolet portions of the spectrum. Table 1 lists a few such systems. In this paper, we shall consider some of the mechanisms for production and relaxation of the energy levels involved in these lasers.
Whole-exome sequencing identifies novel LEPR mutations in individuals with severe early onset obesity.

Objective Obesity is a major public health problem that increases risk for a broad spectrum of co-morbid conditions. Despite evidence for a strong genetic contribution to susceptibility to obesity, previous efforts to discover the relevant genes using positional cloning have failed to account for most of the apparent genetic risk variance.
Policing, Race, and Place

Most Americans live in neighborhoods and communities segregated along race lines, and take this segregation for granted. To the extent they view their communities as racially segregated at all, they assume that this segregation is the largely the result of individual choice or socio-economic status, or perhaps a remnant of de jure segregation. The ambition of this Article is to draw attention to a component of segregation that has been largely ignored: the significant role that criminal law and procedure have played, and continue to play, in maintaining racialized spaces.
Ultrastructure and antigenicity of the unique cell wall pimple of the Candida opaque phenotype.

Cells of Candida albicans WO-1 switch frequently and reversibly between two colony-forming phenotypes, white and opaque. In the white form, budding cells appear similar to those of most other strains of C. albicans, but in the opaque form, budding cells are larger, are bean shaped, and possess pimples on the wall. These pimples exhibit a unique and complex morphology. With scanning electron microscopy, a central pit can be discerned, and in many cases, a bleb can be observed emerging from the pimple center. With transmission electron microscopy, channels are evident in some pimples and vesicles are apparent under the pimple in the cytoplasm, in the actual wall of the pimple, or emerging from the tip of the pimple. A large vacuole predominates in the opaque-cell cytoplasm. This vacuole is usually filled with spaghettilike membranous material and in a minority of cases is filled with vesicles, many of which exhibit a relatively uniform size. An antiserum to opaque cells recognizes three opaque-cell-specific antigens with molecular masses of approximately 14.5, 21, and 31 kilodaltons (kDa). Absorption with nonpermeabilized opaque cells demonstrated that only the 14.5-kDa antigen is on the cell surface; indirect immunogold labeling demonstrated that it is localized in or on the pimple. The possibility is suggested that the vacuole of opaque cells is the origin of membrane-bound vesicles which traverse the wall through specialized pimple structures and emerge from the pimple with an intact outer double membrane, a unique phenomenon in yeast cells. The opaque-cell-specific 14.5-kDa antigen either is in the pimple channel or is a component of the emerging vesicle. The functions of the unique opaque-cell pimple and emerging vesicle are not known. Images
A Thermodynamic Study of the AC-Di-SOL-WATER and CLD-2-WATER Surface Interaction

AbstractAdsorption-desorption studies and Immersional calorimetry were used conjointly to characterize the surface properties of two disintegrants - Ac-Di-Sol and CLD-2. Adsorption-desorption Isotherms were utilized to calculate the Integral and different Gibb's free energies. Non-Isothermal calorimetry was employed to quantify the energies of Interaction between the adsorbate and the adsorbent and obtain the differential enthalpy. These Interactions were determined to be -7.5 and -7.8 kcal per mole for Ac-Di-Sol and CLD-2, respectively. The premature decrease in the differential enthalpies and entropies and the observed immersional and adsorption-desorption hystereses were hypothesized to be the result of an Irreversible swelling process. Differences were observed between CLD-2 and Ac-Di-Sol which were believed to be due to the higher degree of cross-linking In Ac-Di-Sol.
European-American Parents' Ideas About Their Toddlers' Independence and Interdependence

Starting from the position that independence and interdependence are common aspects of human development that are shaped by cultural traditions, this study explores how European-American cultural traditions are reflected in parents' ideas about their children's independence and interdependence. Fifty-six parents with children between 12 and 42 months old (26 boys, 30 girls) participated in a semistructured interview about children and child-rearing. The parents' ideas involved equal proportions of independence and interdependence regardless of child age or child gender, and there was a significant positive correlation between parents' ideas about independence and interdependence. The interviews also revealed that parents' ideas about independence and interdependence are multidimensional. The study moves beyond dichotomous views of independence and interdependence, and the results are discussed further in relation to cultural values.
Long-term culture of human bone marrow stromal cells in the presence of basic fibroblast growth factor.

AbstractBasic fibroblast growth factor (bFGF) is a potent mitogen for human bone marrow stromal cells. Normally, large numbers of human bone marrow stromal cells are difficult to obtain. However, nanogram/ml concentrations of bFGF stimulate the growth of passaged bone marrow stromal cells both in media formulated for optimal growth of stromal cells and in a simple mixture of RPMI-1640 and 10% fetal calf serum facilitating the successive expansion of stromal cells through multiple passages. bFGF also greatly accelerates the formation of a primary stromal cell layer following inoculation of newly harvested bone marrow cells into dishes. In the presence of bFGF, the stromal cells attain high densities, lose their contact inhibition and grow in multilayered sheets. Heparin greatly potentiates the stimulatory effect of low concentrations of bFGF. The effects of bFGF are fully reversible: cells cultured in the presence of this factor for multiple passages revert to normal growth rates following trypsinization a...
Geostatistical-Inspired Metamodeling and Optimization of Nano-CMOS Circuits

With the continuous progression of semiconductor technology, nanoscale effects have become a persistent issue in the design of analog/mixed-signal (AMS) circuits. The cost of exploration and optimization of the design space increases to infeasible levels with conventional design methodologies. Different modeling techniques to reduce the cost of design exploration, while ensuring the accuracy of such models, have been introduced and continue to be a research problem. In this paper, a geostatistical inspired metamodeling and optimization technique is presented for fast and accurate design optimization of nano-CMOS circuits. The proposed design methodology incorporates a simple Kriging based metamodel which efficiently and accurately predicts design performance. The metamodel (instead of the circuit netlist) is subjected to a Gravitational Search Algorithm for optimization. This design methodology is applicable to AMS circuits and is illustrated with the optimization of power consumption of a 45nm CMOS thermal sensor. The method improves the power performance of the thermal sensor by 36.9% while reducing the design optimization time by 90% even with 6 design parameters.
Splenic Cyst Presenting as Severe Hydronephrosis in a Pediatric Patient

Large cystic abdominal masses can represent a diagnostic dilemma despite advanced diagnostic and imaging techniques. We report a case of a large cystic mass initially managed as a giant ureteropelvic junction obstruction, but ultimately found to be a congenital splenic cyst. Focus is placed on the diagnostic evaluation of large cystic abdominal masses.
Spasmodic dysphonia subsequent to head trauma.

• Spasmodic dysphonia (SD) is a low-incidence voice disorder of unknown origin. A subgroup of seven patients with SD from our larger pool of 70 report vocal symptoms subsequent to head injury. This article is a case report of the neurodiagnostic findings, including computed tomography, magnetic resonance imaging, auditory brain-stem response, brain electrical activity mapping, and single photon emission computed tomography for three such patients. For each patient, two or more tests revealed positive neurologic findings. Each test, except computed tomography, demonstrated abnormalities in one or more patients. Two principles of clinical management are derived: (1) information regarding head trauma sustained before SD symptom onset is significant; (2) the absence of neuropathology on a single measure of central nervous system function should not be considered conclusive evidence that no neurologic lesions exist. (Arch Otolaryngol Head Neck Surg1987;113:1107-1110)
Dizziness and Vertigo in the Adolescent

The exact incidence of dizziness and vertigo during adolescence is not known. For those few adolescents who seek outpatient evaluation for these complaints, the majority are diagnosed with migraine headache. The authors provide a discussion of the differential diagnosis, evaluation, and management of vertigo and dizziness in the adolescence with emphasis on migraine headaches, chronic daily headaches, postural orthostatic tachycardia syndrome, and presentations that may require head imaging.
Feminism and Costume History: Synthesis and Reintegration

Like many, my response to feminism, which today is a difficult term, is personal. I consider myself a feminist because of my age and my experiences, coming out of the 1950s. As a costume historian,...
The velocity pattern of weak solar magnetic fields

The proper motion of magnetic elements on the quiet sun has been measured by means of local correlation tracking. The existence of a pattern in the intranetwork (IN) flow is confirmed. This velocity field is consistent with the direct Doppler measurement of the horizontal component of the supergranular velocity field. The IN elements generally move toward the network boundaries. By tracking test points, it is confirmed that the magnetic elements converge in areas corresponding to the magnetic network. But because the IN elements are of random polarity, they cannot contribute to the growth or maintenance of the magnetic network. By calculating the cross correlation between the magnetogram and Dopplergram, it is confirmed that the supergranule boundaries and the magnetic network are roughly correlated.
Presentation of a flashing light following training produces amnesia

Long-Evans rats given exposure to a flashing-light stimulus following one-trial fear conditioning showed amnesia relative to controls not given the flashing-light experience. Together with previous results obtained in this laboratory, it is apparent that the flashing light modulates memory processing.
Experimental evidence for an allergic basis for granuloma formation in man.

GRANULOMA formation is one of the significant reaction patterns of the body in disease. Characterized by tubercles of closely packed epithelioid cells, granulomas are the basic alteration in such chronic diseases as tuberculosis, leprosy, syphilis, sarcoidosis, deep fungus infections and in reactions to foreign material. These epithelioid cells are of reticulo-endothelial origin and may be regularly produced by the introduction of colloidal materials1,2 Other than this, little is known concerning their origin. The present communication describes the production of a specific, hypersensitive, delayed reaction to zirconium which manifested itself as a granuloma.
What's new? Acquiring New information as a process in comprehension

Linguistically, sentences contain both Given information (what the listener is expected to know already) and New information (what the listener is not expected to know already). According to a proposed Given-New Strategy, the listener, in comprehending a sentence, first searches memory for antecedent information that matches the sentence's Given information; he then revises memory by attaching the New information to that antecedent. To provide evidence for this strategy, we presented subjects with pairs of sentences, where the first (the context sentence) provided a context for the second (the target sentence). The subjects were required to press a button when they felt they understood the target sentences. Consistnet with the proposed strategy, Experiment I showed that a target sentence with a definite noun phrase presupposing existence took less time to comprehend when its Given information had a direct antecedent in the context sentence than when it did not. Experiment II ruled out a repetition explanation for Experiment I, and Experiment III demonstrated the same phenomenon for target sentences containing the adverbs still, again, too , and either .
INHIBITION OF TYROSINE KINASE ACTIVITY DECREASES EXPRESSION OF HUMAN SURFACTANT PROTEIN A DURING HUMAN FETAL LUNG DEVELOPMENT IN VITRO .• 357

INHIBITION OF TYROSINE KINASE ACTIVITY DECREASES EXPRESSION OF HUMAN SURFACTANT PROTEIN A DURING HUMAN FETAL LUNG DEVELOPMENT IN VITRO .• 357
γ-tocopherol as a marker of brazilian coffee (Coffea arabica L.) adulteration by corn

The adulteration of coffee with cereals, coffee twigs, etc. is apparently widespread in Brazil with corn being considered the most widely used. No adequate methods are available to detect such contamination in commercial coffee. A new method, based on high-performance liquid chromatography (HPLC) tocopherol determination was developed to detect coffee adulteration by corn. Percentages of α-, β-, γ-, and δ-tocopherol determined by HPLC in six coffee varieties were 29.0, 61.7, 3.3, and 6.0, respectively. Similar values were obtained in six popular coffee brands. The percentages of α-, γ-, and δ-tocopherol in six corn samples were 3.6, 91.3, and 5.1, respectively. These differences could be applied to detect corn in a pure coffee sample intentionally contaminated with corn with the best result obtained with γ-tocopherol. With this methodology, one coffee brand was apparently adulterated (8.9%), most likely with corn. Tocopherol fingerprinting offers the potential to detect adulteration. Keywords: Coffee; adu...
A THEORETICAL ANALYSIS OF INTRACELLULAR OXYGEN DIFFUSION

Abstract Oxygen diffusion rates within cells may be heterogeneous, with more rapid diffusion occurring along intracellular pathways of high oxygen solubility, such as mitochondria. Recent experimental data indicate that tissue oxygen permeability rises sharply in a temperature range associated with phase transitions in lipid membranes suggesting that membranes may function as oxygen “pathway”. The experimental data have been analyzed using theoretical models of diffusion in two-phase media. By assuming muscles to be composed entirely of aqueous cytosol and lipids, cytosolic permeability was determined as a function of temperature by matching the experimental values of tissue permeability with those of model predictions usingin vitrovalues of lipid permeability. Cytosolic permeability ranged from 50% of water permeability (low temperature) to 90% of water permeability (high temperature) and its temperature dependence was distinctly different from that of water. An upper bound for cytosolic permeability was calculated using a physiologic value for protein volume fraction, and lipid permeability was obtained using this cytosolic permeability. A model with a parallel arrangement of lipid and cytosol yielded a value of lipid permeability that was 71% higher than thein vitrovalue. Intracellular permeabilities calculated from tissue permeability values were found to be inconsistent with experimentally reported values for rat cardiac myocytes. Comparison of three different muscles exhibited the same trend of higher permeability with higher lipid content. It is concluded that both lipid and cytosol permeabilities and, hence, tissue permeabilities are different among different muscles and one should exercise caution when data from one muscle is used to calculate or extrapolate values in other muscles. It is conceivable that muscles with very high mitochondrial content, such as diaphragm and cardiac muscles may exhibit an oxygen permeability which is significantly higher than commonly accepted values. These results warrant additional measurements of tissue oxygen permeability at 37 °C, especially for oxidative muscles with high lipid content.
Radiation chemical separation of europium from aqueous lanthanide mixtures

Abstract It is observed that the γ radiolysis of dilute aqueous sulphuric acid solutions of Eu(III) ions in the presence of 2-propanol leads to the precipitation of dissolved europium as europous sulphate with G=5.9. Pulse radiolytic evidence is provided for the mechanism involving the reduction of Eu(III) by (CH3)2-Ċ-OH radicals produced in situ. Use of this observation towards a feasible separation method of europium from a mixture of lanthanides in aqueous solution is discussed.
How to use interaction terms in BMA: Reply to Crespo Cuaresma's comment on Masanjala and Papageorgiou (2008)

Jesus Crespo Cuaresma (How different is Africa? A comment on Masanjala and Papageorgiou. Journal of Applied Econometrics, 2011) shows that the results in Masanjala and Papageorgiou (Rough and lonely road to prosperity: a reexamination of the sources of growth in Africa using Bayesian model averaging. Journal of Applied Econometrics 2008; 23(5): 671–682) are sensitive to an alternative prior model structure in considering interaction terms. As a side issue, the algorithm for averaging over models is also challenged. In this reply I show that the prior used in Masanjala and Papageorgiou is as sensible as the prior suggested by Crespo Cuaresma. What we learn from Crespo Cuaresma's comment and this reply is that further effort should be dedicated to the study of parameter heterogeneity in the framework of BMA methods. Copyright © 2011 John Wiley & Sons, Ltd.
Outside-In: The Effects of External Threat on State Centralization:

Although centralization is thought to be a common response to external threats to the state, few theories develop the mechanisms by which domestic centralization occurs. Fewer still consistently demonstrate that centralization is indeed a common response to external threats in all states. This article therefore develops a comprehensive theory of domestic change in the shadow of external threat. Salient threats to the state create strong incentives for opposition forces to support the leader in power, even in non-democracies. The leadership then uses these favorable domestic political climates to decrease the number of institutional veto points that can stop future leader-driven policy changes. Collectively, this two-part theory provides a unified model of domestic behavioral change (also known as rally effects) and institutional centralization (defined by a declining number of veto players). In addition, by defining salient threats as challenges to homeland territory, the article provides some of the firs...
MR properties of brown and white adipose tissues.

Purpose To explore the MR (magnetic resonance) signatures of brown adipose tissue (BAT) compared to white adipose tissue (WAT) using single-voxel MR spectroscopy.
Determination of celecoxib in human plasma using solid-phase extraction and high-performance liquid chromatography

A simple reversed phase high-performance liquid chromatography (HPLC) method was developed for determination of celecoxib levels in human plasma. The procedure involves solid-phase extraction of celecoxib and the internal standard (SC-236) from plasma using C(18) extraction cartridges. The chromatographic separation of celecoxib and SC-236 was achieved with a Nova Pak C(8) column (3.8 mm x 150 mm) eluted with a mobile phase consisting of acetonitrile-tetrahydrofuran-sodium acetate buffer (pH 5.0) in the ratio of 30:8:62. An ultraviolet light detector with the wavelength set at 215 nm was employed for detection. Celecoxib was well resolved from the plasma constituents and the internal standard. The extraction recovery of celecoxib and SC-236 from human plasma was greater than 88%. Linear calibration curves were established over a concentration range of 40-4000 ng/ml when 0.25 ml aliquots of plasma were used. The inter- and intra-day R.S.D. for the assay was less than 12 and 5%, respectively. This assay has been applied to the analysis of celecoxib levels in plasma samples collected from healthy participants entered into a Phase II clinical study.
Export Promotion in the New Global Division of Labor: The Case of the South Korean Automobile Industry

The comparative study of three South Korean automobile companies illuminates the growing dependence of new entrants on the integrated global market. The structural barriers of a tightly integrated global market redefine the strategic role of export promotion by late industrializers in the world economy dominated by transnational corporations (TNCs). New forms of export promotion which are negotiated with and internalized by specific firms entail considerable political and economic costs. The integrated global market requires development strategies reconceptualizing the advantages of trade, foreign investment, technology, and the global division of labor.
High-level cell-free synthesis yields of proteins containing site-specific non-natural amino acids

We describe an E. coli-based cell-free system for the production of proteins with a non-natural amino acid (nnAA) incorporated site-specifically (modified protein). The mutant Methanococcus jannaschii tyrosyl-tRNA synthetase (mTyrRS) and tRNA(Tyr) pair were used as orthogonal elements. The mTyrRS experienced proteolysis and modified protein yields improved with higher synthetase addition (200-300 microg/mL). Product yields were also improved by increasing levels of total protein to 20 mg protein/mL and available vesicle surface area to 0.5 m(2)/mL. This new E. coli-based cell-free procedure produced up to 400 microg/mL of eCAT109pAz, 660 microg/mL of eDHFR10pAz, and 210 microg/mL of mDHFR31pAz with p-azido-L-phenylalanine (pAz) incorporated site-specifically at the amber nonsense codon. O-methyl-L-tyrosine and p-acetyl-L-phenylalanine were incorporated by similar protocols. The desired specificity for incorporation of the nnAA by the cell-free system was confirmed. Additionally, the modified proteins were enzymatically active and reactive for copper(I)-catalyzed (3 + 2) cycloadditions (click chemistry).
MEL-type Pure-Silica Zeolite Nanocrystals Prepared by an Evaporation-Assisted Two-Stage Synthesis Method as Ultra-Low-k Materials†

A MEL-type pure-silica zeolite (PSZ), prepared by spin-on of nanoparticle suspensions, has been shown to be a promising ultra-low-dielectric-constant (k) material because of its high mechanical strength, hydrophobicity, and chemical stability. In our previous works, a two-stage synthesis method was used to synthesize a MEL-zeolite nanoparticle suspension, in which both nanocrystal yield and particle size of the zeolite suspension increased with increasing synthesis time. For instance, at a crystal yield of 63%, the particle size is 80 nm, which has proved to be too large because it introduces a number of problems for the spin-on films, including large surface roughness, surface striations, and large mesopores. In the current study, the two-stage synthesis method is modified into an evaporation-assisted two-stage method by adding a solvent-evaporation process between the two thermal-treatment steps. The modified method can yield much smaller particle sizes (e.g., 14 vs. 80 nm) while maintaining the same nanocrystal yields as the two-stage synthesis. Furthermore, the nanoparticle suspensions from the evaporation-assisted two-stage synthesis show a bimodal particle size distribution. The primary nanoparticles are around 14 nm in size and are stable in the final suspension with 60% solvent evaporation. The factors that affect nanocrystal synthesis are discussed, including the concentration, pH value, and viscosity. Spin-on films prepared by using suspensions synthesized this way have no striations and improved elastic modulus (9.67 ± 1.48 GPa vs. 7.82 ± 1.30 GPa), as well as a similar k value (1.91 ± 0.09 vs. 1.89 ± 0.08) to the previous two-stage synthesized films.
Auditory frequency generalization in the goldfish (Carassius auratus)

Auditory frequency generalization in the goldfish was studied at five points within the best hearing range through the use of classical respiratory conditioning. Each experimental group received single-stimulus conditioning sessions at one of five stimulus frequencies (100, 200, 400, 800, and 1600 Hz), and were subsequently tested for generalization at eight neighboring frequencies. All stimuli were presented 30 db above absolute threshold. Significant generalization decrements were found for all subjects. For the subjects conditioned in the range between 100 and 800 Hz, a nearly complete failure to generalize was found at one octave above and below the training frequency. The subjects conditioned at 1600 Hz produced relatively more flat gradients between 900 and 2000 Hz. The widths of the generalization gradients, expressed in Hz, increased as a power function of frequency with a slope greater than one.
Reply to: Re: Intraoperative ultrasonography during planned liver resections remains an important surgical tool ((2007) 21: 1280-1283).

We thank Prof. Cerwenka for his informative and insightful comments regarding our article. He highlights the importance of high-quality preoperative imaging, and that oftentimes this necessitates repeating studies using liverspecific protocols. Contrast-enhanced liver ultrasonography looks promising but its use in the USA is still considered investigational. Overall, his clinical experience is very similar to ours. Despite the impressive advances in crosssectional imaging over the last decade, intraoperative liver ultrasonography still plays an important role in guiding the surgical management of many patients with both benign and malignant liver lesions.
Microframework for Modeling of High-Emitting Vehicles

High emitters represent a small fraction of the vehicle fleet, yet they are responsible for a large portion of the total mobile source emissions. Drive-cycle-specific high-emitter cut points for the identification of high-emitter vehicles are first developed. A microscopic model for estimating high-emitter vehicle emissions by using second-by-second emission data is developed subsequently. The proposed model estimates vehicle emissions with a margin of error of 10% when compared with in-laboratory bag emission measurements. The model was incorporated in the INTEGRATION traffic assignment and simulation software for the environmental assessment of alternative traffic operational projects, including emerging intelligent transportation system initiatives.
Mechanistic Studies of R67 Dihydrofolate Reductase EFFECTS OF pH AND AN H62C MUTATION

R67 dihydrofolate reductase (DHFR) is encoded by an R-plasmid, and expression of this enzyme in bacteria confers resistance to the antibacterial drug, trimethoprim. This DHFR variant is not homologous in either sequence or structure with chromosomal DHFRs. The crystal structure of tetrameric R67 DHFR indicates a single active site pore that traverses the length of the molecule (Narayana, N., Matthews, D. A., Howell, E. E., and Xuong, N.-H. (1995) Nat. Struct. Biol. 2, 1018-1025). A pH profile of enzyme activity in R67 DHFR displays an acidic pKa that is protein concentration-dependent. This pKa describes dissociation of active tetramer into two relatively inactive dimers upon protonation of His-62 and the symmetry-related His-162, His-262, and His-362 residues at the dimer-dimer interfaces. Construction of an H62C mutation results in stabilization of the active tetramer via disulfide bond formation at the dimer-dimer interfaces. The oxidized, tetrameric form of H62C R67 DHFR is quite active at pH 7, and a pH profile displays increasing activity at low pH. These results indicate protonated dihydrofolate (pKa = 2.59) is the productive substrate and that R67 DHFR does not possess a proton donor.
Parasitic tolerant designs of sampled data filters using switched capacitors and unity gain amplifiers

Abstract New and systematic procedures are presented for realizing sampled data filter (SDF) functions using switched capacitors (SCs) and unity gain amplifiers (UGAs). The procedures are attractive and simple to implement. Any SDF, recursive or non-recursive and of any order, can be realized using the methods presented. The designs of biquadratic SDFs is discussed in detail. The resulting realizations possess the property that the numerator and denominator coefficients of the SDF functions can be controlled by independent capacitance ratios. This makes the filters attractive for adaptive applications. The sensitivity properties of the resulting filters are analyzed and guidelines given for obtaining low sensitivity realizations. A method is also suggested to make the filters relatively insensitive to the parasitic capacitances in the circuit. Finally, a step by step procedure, easily implemented in a computer, is given. Starting from the given analog filter specifications, the method yields a design that has very low sensitivity, uses minimum total capacitance and is tolerant of the various parasitic capacitances in the circuit. Experimental results show very good agreement with the theoretical analysis.
Activation of a NO-cyclic GMP system by NO donors potentiates β-endorphin-induced antinociception in the mouse

Nitric oxide (NO) donors such as sodium nitroprusside (SNP, 0.01-1 micrograms) or 3-morpholino-sydnonimine (SIN-1, 0.1-10 micrograms) administered intracerebroventricularly (i.c.v) produced a dose-dependent potentiation of beta-endorphin-induced antinociception assessed by the tail-flick test in ICR mice. The same i.c.v. treatment with SNP or SIN-1 did not affect the antinociception induced by mu-, delta-, or kappa-opioid receptor agonists. The goal of the present study was to determine if the potentiation of the beta-endorphin-induced antinociception by NO donors is mediated by the activation of NO-cGMP system. Co-administration of hemoglobin (30-120 micrograms) or methylene blue (1.25-5 micrograms), but not N omega-nitro-L-arginine (1-5 micrograms) given i.c.v. dose-dependently attenuated the potentiating effects of SNP or SIN-1 on beta-endorphin-induced antinociception. However, the same i.c.v. treatments of mice with hemoglobin, methylene blue or N omega-nitro-L-arginine did not directly affect the i.c.v. administered beta-endorphin-induced antinociception. On the other hand, the treatment of mice with a combination of NO donor (SNP, 0.1 micrograms or SIN-1, 1 microgram) and zaprinast (a cGMP phosphodiesterase inhibitor, 1 microgram) further potentiated beta-endorphin-induced antinociception. These results indicate that the potentiating effect of SNP or SIN-1 on beta-endorphin-induced antinociception is mediated by the increased production of NO-cyclic GMP in the brain. However, the NO-cGMP system is not directly involved in the beta-endorphin-induced antinociception.
Quantitative wound biopsies

Abstract One or more quantitative techniques have been used to monitor major surgical and burn wounds (6, 37–40). Quantitative wound bacteriology is currently used in a variety of clinical environments that encompass many disciplines, of which surgery predominates (37). This technique when appropriately used can provide the surgeon with an accurate tool to make clinical decisions about wound treatment, without the concern for complications of infection. We have used this method of surveillance for the past 4 yr at the Shriners Burns Institute. The first year our nosocomial rate was 34.7%; however, over the subsequent years we have decreased our nosocomial infection rate to 7.5% with a mortality rate of 0.004% (Fig. 1) based on a total of 675 admissions per annum.
The political context of conflict and cooperation over international river basins

ABSTRACT Along with land and air, water is the most vital human resource. It also is scarce, maldistributed and often shared internationally. Hence, it is frequently the focus of serious conflict among nations, especially the riparians of transnational rivers. Population growth and economic development exacerbate these conjlictual tendencies. A predictive theory of conflict and cooperation over transnational rivers is urgently needed. This article presents a power-analytic framework and some initial steps toward such a theory. After explaining the basic concepts of conflict and cooperation, it briefly examines the contributions of international law and the best known typologies of conflict, presenting reasons for their inadequacy The most prominent models of conflict behavior are also examined and their contributions noted along with their overall incapacity. A few direct but incomplete attempts at political modelling of transnational river conflicts are similarly discussed. The remainder of the article s...
A study aimed at characterizing the interfacial structure in a tin-silver solder on nickel-coated copper plate during aging

This paper highlights the interfacial structure of tin-silver (Sn-3·5Ag) solder on nickel-coated copper pads during aging performance studies at a tem- perature of 150 ◦ C for up to 96 h. Experimental results revealed the as-solidified solder bump made from using the lead-free solder (Sn-3·5Ag) exhibited or showed a thin layer of the tin-nickel-copper intermetallic compound (IMC) at the sol- der/substrate interface. This includes a sub-layer having a planar structure imme- diately adjacent to the Ni-coating and a blocky structure on the inside of the solder. Aging performance studies revealed the thickness of both the IMC layer and the sub-layer, having a planar structure, to increase with an increase in aging time. The observed increase was essentially non-linear. Fine microscopic cracks were observed to occur at the interfaces of the planar sub-layer and the block sub-layer.
Extraction of magnesium and copper using a surfactant and water in supercritical carbon dioxide

Abstract Magnesium and copper were extracted in supercritical carbon dioxide with the addition of a surfactant, ammonium carboxylate perfluoropolyether, and water. For Mg2+ the percent extracted reached a maximum of 65% at a temperature of 393 K, a pressure of 220 bar and a mole ratio of water to surfactant, w 0 of 185. For Cu2+ the maximum percent extracted was 73% at a temperature of 333 K, a pressure of 250 bar and a w 0 of 333. The influence of parameters including molar ratio of surfactant to metal and molar ratio of water to surfactant was examined for Mg2+ extraction at a temperature of 333 K and pressure of 150 bar. The percent Mg2+ extracted increased from approximately 19–31% as the mole ratio of surfactant to Mg2+ increased from 0.4 to 4. The percent extracted does not change appreciably with further increases in surfactant/metal ratio. The percent Mg2+ extracted increased from 5% up to 31% as the molar ratio of water to surfactant increased from 0 to 5.6. Further increases of molar ratio of water to surfactant showed no significant increase in metal extracted. The system was operated as a closed-system until equilibrium was achieved.
Metabolism of β-aminopropionitrile and its teratogenic activity in rats

The administration of β-aminopropionitrile (BAPN) to pregnant rats induced various fetal anomalies including a high percentage of cleft palate. Following oral administration BAPN was found along with its deaminatedoxidized derivative cyanoacetic acid (CAA) in embryos, placentas, and maternal tissues, serum, and urine. BAPN levels reached a maximum in tissue and serum 6 hours after treatment, were maintained for about 3 hours more, then sharply declined to negligible amounts by 24 hours. CAA levels however gradually rose and high levels were still present at 24 hours. Similar amounts of BAPN were found in tissues after its administration on either day 14. 15, or 16 of gestation; however, only on day 15 was there a positive correlation between embryonic levels of BAPN and cleft-palate production. Thus 6 hours after BAPN treatment on day 15 embryonic levels of 106, 42, or 16 μg BAPN per g of tissue corresponded to a cleft-palate incidence of 98, 28, or 0% respectively. Oral administration of CAA produced no cleft palate even though high embryonic levels of CAA were attained. These data indicate that BAPN itself is teratogenic and that it acts within a narrow period of time on day 15 in producing cleft palate.
Pre-irradiation 9-Amino [20s] camptothecin (9-AC) in patients with newly diagnosed glioblastoma multiforme

Purpose: To evaluate the efficacy of 9-amino [20s] camptothecin (9-AC) given before radiation therapy to patients with newly diagnosed glioblastoma multiforme (GBM). Methods: Eligible patients had newly diagnosed GBM who had residual measurable contrast-enhancing tumor. The trial was a phase 2 trial of 9-AC at 1100 μg/m2 /24 h infused over 72 h every two weeks for up to six cycles in patients with newly diagnosed GBM before radiation therapy. Results: Fourteen patients entered the study and all were evaluable. All of the patients had progressive disease by imaging criteria after at least two cycles of 9-AC (1 month). The median overall survival was 7.5 months (range 1.5–18 months). The most common adverse event was transient lymphopenia (grade 3–4). One patient developed grade 4 neutropenic fever that resolved after three days of diagnosis. Conclusions: 9-AC lacks activity against glioblastoma multiforme (GBM). Further studies looking at the efficacy of 9-AC in GBM may be futile.
Conservation Laws of Evolution Equations: Generic Non-existence

Evolution-type partial differential equations in one space variable are formulated in terms of exterior differential systems. The space of conservation laws is discussed in this geometric context, and a familiar classical condition for conservation laws is derived. It is shown that the generic even-order evolution equation with one space variable possesses no conservation laws of order greater than the order of the equation.
Saving the "library of life"

A broad program of freezing species in threatened ecospheres could preserve biodiversity for eventual use by future generations. Sampling without studying can lower costs dramatically. Local labor can do most of the gathering. Plausible costs of collecting and cryogenically suspending the tropical rain forest species, at a sampling fraction of 10(-6), are about 2 billion dollars for a full century. Much more information than species DNA will be saved, allowing future biotechnology to derive high information content and perhaps even resurrect then-extinct species. Parallel programs of in situ and other ex situ preservation are essential to allow later expression of frozen genomes in members of the same genus. This is a broad proposal that should be debated throughout the entire scientific community.
The Absorption of Radio Waves in the Upper Atmosphere

Recent measurements have shown that radio waves below 150 meters fall off in intensity faster than required by an inverse square law for distances up to 1000 miles. This points to absorption of the wave by the medium, in this case the upper atmosphere. The absorption of the waves variously polarized is calculated on the assumption that it results from collisions between the electrons and molecules of the atmosphere. With reasonable average values of the electronic and molecular densities the amplitude $A$ of the wave $\ensuremath{\lambda}$ cms at a distance $x$ cms is $A=a{x}^{\ensuremath{-}1}exp(\ensuremath{-}11.8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}16}{\ensuremath{\lambda}}^{2}x)$, theoretically valid for waves from 16 to 160 meters to distances of 1000 miles. This agrees well enough with the scant range and intensity data, and it is pointed out that an extension of these data may lead to more exact knowledge of the overhead electronic and molecular pressures. From the absorption curves interesting possibilities appear of polarization of waves in the broadcast band 200-600 meters.
The number of distinguishable catalytic sites on Rh-, Pt- and Pd- silica catalysts in some ring opening and exchange reactions

Abstract The number of different catalytic sites, φs is the number which can be distinguished by catalytic data alone. This number may differ from the number of distinguishable sites identifiable by physical means, IR of adsorbed CO for example. This paper surveys the problem as exemplified by analysis of catalytic data from the hydrogenolysis of methylcyclopropane and the isotopic exchange between D2 and alkanes on three sets of catalysts, Rh/SiO2 Pd/SiO2 and Pt/SiO2, the members of which varied widely in percentage exposed. All measurements of turnover frequency were accompanied by one or more selectivity data. In the hydrogenolysis experiments the selectivity was the ratio of isobutane to butane in the product and, in alkane exchange, the concentrations of the various exchanged species, δ1, δ2, δ3 … provide the selectivity data. Analysis of these data provide a powerful tool for diagnosing φs. Application of selectivity data is aided by accompanying turnover frequency data particularly when these derive from two or more different conditions of catalyst pretreatment, but some conclusions can often be drawn from turnover frequency data for two or more reactions or conditions of pretreatment.
Simultaneous expression of tissue factor and tissue factor pathway inhibitor by human monocytes. A potential mechanism for localized control of blood coagulation.

Cells of monocytic lineage can initiate extravascular fibrin deposition via expression of blood coagulation mediators. This report is about experiments on three mechanisms with the potential to modulate monocyte-initiated coagulation. Monocyte procoagulant activity was examined as a function of lipid cofactor, protein cofactor, and specific inhibitor expression during short-term culture in vitro. Lipid cofactor activity was measured as the initial rate of factor X activation by intrinsic-pathway components, the assembly of which depends on this cofactor. Lipid cofactor activity levels changed by < 30% during 48-h culture. Protein cofactor, i.e., tissue factor (TF) antigen was measured by enzyme immunoassay. It increased from 461 pg/ml to a maximum value of 3,550 pg/ml at 24 h and remained at 70% of this value. Specific TF activity, measured as factor VII-dependent factor X activation rate, decreased from 54 to 18 nM FXa/min between 24 and 48 h. TF activity did not correlate well with either lipid cofactor or TF protein levels. In contrast, the decrease in TF activity coincided in time with maximal expression of tissue factor pathway inhibitor (TFPI) mRNA, which was determined using reverse transcriptase polymerase chain reaction (RT-PCR), and with maximal TFPI protein levels measured by immunoassay. The number of mRNA copies coding for TFPI and TF in freshly isolated blood monocytes were 46 and 20 copies/cells, respectively. These values increased to 220 and 63 copies/cell during short-term cell culture in the presence of endotoxin. Results demonstrate concomitant expression by monocytes of genes coding for both the essential protein cofactor and the specific inhibitor of the extrinsic coagulation pathway. Together with functional and antigenic analyses, they also imply that the initiation of blood clotting by extravascular monocyte/macrophages can be modulated locally by TFPI independently of plasma sources of the inhibitor.
The Cognitive Mediation Hypothesis Revisited: An Empirical Response to Methodological and Theoretical Criticism

The cognitive mediation hypothesis has become a well-established assumption in persuasion theory. However, several theoretical and methodological criticisms have been raised to call this assumption into question. Three experiments that address these criticisms were conducted to provide a more direct test of the cognitive mediation hypothesis. Using the forewarning effect as a testing arena, Experiment I demonstrated that interference with either motivation or ability to counterargue reduced fore-warning-induced resistance to persuasion. Experiment 2 demonstrated that exposure to counterarguments generated by others and self-generated counterarguments were functionally equivalent and redundant. Experiment 3 used a path-analytic approach to demonstrate that the persuasion differences produced by forewarning were eliminated by covarying the effect of cognitive responses generated between forewarning and message exposure. Taken together, the three experiments provide converging support for the cognitive media...