cssi/SciSciGPT-SciSciNet huggingface dataset:
2‐(3‐Methylbutoxy)‐1,3‐benzodithiolane

(1; R = CH2CH2CHMe2) [55315-56-5] C12H16OS2 (MW 240.42) InChI = 1S/C12H16OS2/c1-9(2)7-8-13-12-14-10-5-3-4-6-11(10)15-12/h3-6,9,12H,7-8H2,1-2H3 InChIKey = BAAKQYVLPCAXGF-UHFFFAOYSA-N (2; R = n-C3H7) [55315-54-3] C10H12OS2 (MW 212.36) InChI = 1S/C10H12OS2/c1-2-7-11-10-12-8-5-3-4-6-9(8)13-10/h3-6,10H,2,7H2,1H3 InChIKey = STOWVAJUKWEMNA-UHFFFAOYSA-N (3; R = n-C4H9) [55315-55-4] C11H14OS2 (MW 226.39) InChI = 1S/C11H14OS2/c1-2-3-8-12-11-13-9-6-4-5-7-10(9)14-11/h4-7,11H,2-3,8H2,1H3 InChIKey = UEPAXRJVNRXRBR-UHFFFAOYSA-N (4; R = CH2CH2OCH2CH2OMe) [131549-15-0] C12H16O3S2 (MW 272.42) InChI = 1S/C12H16O3S2/c1-13-6-7-14-8-9-15-12-16-10-4-2-3-5-11(10)17-12/h2-5,12H,6-9H2,1H3 InChIKey = ZKVCIIBVXVOOBU-UHFFFAOYSA-N (reagent for synthesis of 2-substituted 1,3-benzodithiolanes by substitution of the 2-alkoxy group by various carbon and hetero nucleophiles; 2-lithio-1,3-benzodithiolanes are useful for nucleophilic acylation) Physical Data: (1) pale yellow oil; bp 120–125 °C/0.1 mmHg. (2) bp 104–106 °C/0.1 mmHg. (3) bp 116–118 °C/0.1 mmHg. (4) bp 152–156 °C/0.5 mmHg. Preparative Methods: prepared1 by adding dropwise 0.1 L of a solution of Anthranilic Acid (3 M in dioxane) to a gently refluxing solution of Isopentyl Nitrite (0.36 M), 3-methylbutanol (0.60 M) and Carbon Disulfide (0.15 L) in 1,2-dichloroethane (0.8 L). Diazotization of anthranilic acid with isopentyl nitrite generates, beside 1 equiv of 3-methylbutanol, reactive benzyne, which reacts with excess SCS to give 1,3-benzodithiole-2-carbene. Reaction of this carbene with 3-methylbutanol, as described by Nakayama,1 gives 2-(3-methylbutoxy)-1,3-benzodithiolane (1) in about 50% yield. This method has been extended to prepare 2-(propoxy)-1,3-benzodithiolanes (2) and 2-(butoxy)-1,3-benzodithiolanes (3), but the yields are poor. Similarly, when a mixture of freshly prepared diazonium-2-carboxylate (from anthranilic acid, 25.7 g),3 2-(2-methoxyethoxy)ethanol (32 mL), CS2 (63 mL), and CH2Cl2 (1.125 L) is allowed to reflux (1.5 h), about 25% yield of 2-[(2-methoxyethoxy)ethoxy]-1,3-benzothiole (4) can be obtained readily.2 Handling, Storage, and Precautions: dithiolane (1) is a stable and easy to handle material at ambient temperature. Thermally, it is unstable, undergoing substantial decomposition during distillation to give mainly 2,2′-bi(1,3-benzodithiolylidene).4a Use in a fume hood.
The Importance of Fathers

ABSTRACT The purpose of this study was to explore the relation between self-esteem, sociodemographic factors, father-daughter relationships, and sexual risk-taking in an economically diverse group of late-adolescent African American girls. Participants were 100 African American adolescent girls from the Southeast region of the U.S. Regression analyses revealed that fathers' education was the most powerful predictor of sexual risk, with self-esteem emerging as a significant, yet less powerful predictor. A subset of the initial sample participated in a secondary, qualitative study explicitly examining father-daughter communication about sexuality. Thematic analysis revealed three distinct categories of father-daughter sexual communication. Participants associated directive and insightful communication styles with positive father-daughter relationships and less risky sexual behavior. Absent/avoidant communication was linked to rejection, regret, and more risky sexual behavior. Results suggest that impact of ...
Gastroscopic observations during anaphylaxis in a human.

Anaphlaxis to a test dose of urographic medium was shortly followed by abdominal pain and hematemesis. Endoscopy revealed a severe hemorrhagic gastritis. The author comments on the possible relationship between anaphylaxis and the intense but transient gastric mucosal reaction.
Old open clusters as probes of stellar and galactic disk evolution

Open clusters have traditionally been used to investigate the chemical evolution of the Galactic disk, using the assumption that they reflect the chemical abundance of the interstellar medium (ISM). This assumption was tested by analyzing two samples of ~20 old open cluster spectra, one of evolved, red-horizontal-branch stars in the ~10-Gyr-old NGC 6791, and the second of unevolved G-dwarfs in the younger, ~4.5-Gyr-old M 67. Unlike many globular clusters, the band and line strengths of CN, CH, Ca, and Fe show neither a bimodal distribution, nor a CN-to-CH anticorrelation. However, the data for the evolved stars of NGC 6791 do provide evidence for a dispersion in CN band strengths. If the explanation for this is that stellar evolution after ~4.5 Gyr produces CN inhomogeneities, the CN-band strengths of very old, evolved stars are questionable tracers of the initial chemical abundance of the ISM. Stellar clusters are often used to study stellar evolution because such stars are coeval and equidistant. The results are then extrapolated to disk stars with little proof that the old disk stars originated in clusters. An essential link may be moving groups, stars that are not in close physical proximity but have similar kinematics and [Fe/H]. The age of eight HR 1614 Moving Group dwarfs was investigated, and it was determined that all eight are at least 3 Gyr old. This supports the scenario that many of the disk field stars formed in open clusters which subsequently were disrupted. Theories about Galactic disk evolution can be evaluated by comparing their predictions to the old open cluster system. The "inside-out" type of theory predicts that the ISM in the inner part of the Galactic disk is older and more chemically evolved than that of the outer part. Two samples of old open clusters, one from the inner and one from the outer disk, had significantly different mean [Fe/H] values, but similar mean ages. The former is in accordance with inside-out theories: the latter is not. The system of old open clusters appears to have extended to a larger radial distance ~5-7 Gyr ago, also not consistent with inside-out theories. These results can not be attributed to the preferential destruction of inner-disk open clusters.
FORTH, a software solution to real-time computing problems

Some common real-time computing problems are discussed, namely, the programming and testing of devices, problems relating to program execution speed, the timing of experimental events, and the programming of multiple parallel events. The programming language FORTH is shown to be capable of providing solutions to all of these problems. In addition, FORTH has the advantages of being an interpretive and extensible language with both high-level and low-level capabilities, while at the same time being efficient and fast in execution.
Atrial fibrillation: the epidemic of the new millennium.

Hart and colleagues' meta-analysis in this issue reemphasizes the value of anticoagulation in patients with atrial fibrillation, especially those at highest risk for stroke. These findings may lead...
Picosecond Dynamics of Colloidal Gold Nanoparticles

Colloidal gold nanoparticles with an average radius of 15 nm have a surface plasmon absorption band at 530 nm. Excitation by laser pulses of 450 fs duration, and wavelength of 600 or 380 nm “bleached” the plasmon band and produced a transient absorption at the wings of the “bleach” spectrum. The transient absorption was found to have a similar temporal behavior at different wavelengths. Analysis of their temporal behavior showed two time constants: 2.5 ps, and a slower component of >50 ps. Laser excitation close to the plasmon band at 600 nm leads to the formation of “hot” non-Fermi electronic distribution within the colloidal particles. Transient absorption from these “hot” electrons led to different absorptions from that of the plasmon absorption of “cold” electrons. The “hot” electrons relax via electron−phonon coupling in 2.5 ps, and the phonon−phonon relaxation of the lattice occurs in >50 ps. At 380 nm excitation, the amplitude of the blue wing becomes smaller, and the slow component becomes longer...
Understanding hysterectomies: Sexual satisfaction and quality of life

Because a hysterectomy is one of the more frequently performed surgical procedures in the U.S., we used a causal model to study those women who had and had not experienced a hysterectomy. Using family stress theory, we examined the quality of life of these two groups of women as it was related to physiological and psychological health stressors, family stress, resources, meaning of the stressors, and the perceived sexual satisfaction. A survey research design was employed with a national random sample of women (N = 346) between the ages of 45 and 60 who were members of an association of college‐educated women. Research instruments included the Family Inventory of Life Events and Changes Scale, Women's Health Questionnaire, Family Crisis Oriented Personal Evaluation Scale, Index of Sexual Satisfaction, and Generalized Life Contentment Scale. There was no significant difference in the quality of life of those women who had and had not experienced a hysterectomy, but women who had a hysterectomy perceived gr...
Phylogenetic Relationship among the Malaria Parasites Based on Small Subunit rRNA Gene Sequences: Monophyletic Nature of the Human Malaria Parasite,Plasmodium falciparum1

We analyzed the small subunit ribosomal RNA (SSUrRNA) gene sequences from 13 malaria species parasitic to humans, chimpanzees/gorillas, Old World monkeys, rodents, birds, and lizards in order to reconstruct the phylogenetic relationships among the Plasmodium species. The SSUrRNA genes of Plasmodium vivax and P. ovale were sequenced by the dideoxy method in our laboratory; other sequences were retrived from GenBank. These sequences were aligned with the SSUrRNA gene sequence of outgroup species, Paramecium and Toxoplasma. After gaps and ambiguous regions were deleted, the aligned sequences were used for phylogenetic analysis by maximum likelihood and distance methods. The tree defines two major clades, the first with the bird and reptile parasites, the second with the rest of the species. The two bird parasites, P. gallinaceum and P. lophurae, do not closely cluster with human, chimpanzee/gorilla, Old World monkey, or rodent parasites, but cluster with the lizard parasites. P. vivax clusters with three Old World monkey parasites, P. cynomolgi, P. fragile, and P. knowlesi in decreasing order of closeness. P. ovale, while in a separate clade, is more closely related to P. vivax than to P. malarie or P. falciparum. P. malariae and P. berghei do not closely cluster with any of the other clades or with each other. Statistical analysis proves that the placement of P. falciparum in the bird malaria clade is less likely than in the mammalian malaria clade. Our analysis reveals that: (1) human malaria parasites have an evolutionary independent origin; (2) P. falciparum is most closely related to P. reichenowi and did not arise from lateral transfer of a bird parasite, as was previously suggested; and (3) the lizard malaria parasites are true members of the genus Plasmodium.
Control choices and network effects in hypertext systems

When the utility of a hypertext system depends on the number of users and amount of data in the system, the system exhibits network effects. This paper examines how the core differences in control assumptions between monolithic hypertext systems, open hypermedia systems, and the Web, lead to different incentive structures for readers and content providers and hence varying levels of
Discourse and dialogue processing in spoken intelligent tutoring systems

In recent years, the development of intelligent tutoring dialogue systems has become more prevalent, in an attempt to close the performance gap between human and computer tutors. Tutoring applications differ in many ways, however, from the types of applications for which spoken dialogue systems are typically developed. This talk will illustrate some of the opportunities and challenges in this area, focusing on issues such as affective reasoning, discourse and dialogue analysis, and performance evaluation.
O2 reduction at the Pt/Nafion interface in 85% concentrated H3PO4

The kinetics of oxygen electroreduction have been studied on a smooth platinum electrode coated with Nafion® in concentrated 85% H3PO4. The effects of Nafion® coatings of different thickness on O2 electroreduction at a smooth Pt rotating disk electrode with 85% phosphoric acid as the bulk electrolyte were examined. The kinetic current increases with increasing Nafion® film thickness while the diffusion limiting current decreases with increasing Nafion® film thickness. A O2 concentration profile model for the Pt/Nafion®/bulk electrolyte has been established, and this model can be used to explain the O2 reduction polarization results. The performance of Nafion®-modified, high surface area Pt/carbon air cathodes for use in the H2–air concentrated phosphoric acid fuel cell was also studied.
Scanning tunneling microscopy based lithography of octadecanethiol on Au and GaAs

We have demonstrated that low energy electron beams (≤10 eV) from a scanning tunneling microscope (STM) can be used to modify a surface of self‐assembled monolayers of octadecanethiol [ODT, CH3(CH2)17SH] on gold and GaAs. STM modification in air was used to produce grating patterns up to 140 μm in total size. Line sizes as small as 15 nm were produced in ODT on GaAs at a bias of 10 V, and slightly larger sizes were produced on the gold substrate. Biases of greater than 4 V are necessary for the fabrication of these raised lines, as observed with an atomic force microscope (AFM). The patterns in ODT on gold were successfully transferred into the gold layer with a wet chemical etch demonstrating that the monolayer performs as a positive electron beam resist.
Evaluations of the chemical mass balance method for determining contributions of gasoline and diesel exhaust to ambient carbonaceous aerosols.

Abstract The US. Department of Energy Gasoline/Diesel PM Split Study was conducted to assess the sources of uncertainties in using an organic compound–based chemical mass balance receptor model to quantify the relative contributions of emissions from gasoline (or spark ignition [SI]) and diesel (or compression ignition [CI]) engines to ambient concentrations of fine particulate matter (PM2.5) in California’s South Coast Air Basin (SOCAB). In this study, several groups worked cooperatively on source and ambient sample collection and quality assurance aspects of the study but worked independently to perform chemical analysis and source apportionment. Ambient sampling included daily 24–hr PM2.5 samples at two air quality–monitoring stations, several regional urban locations, and along freeway routes and surface streets with varying proportions of automobile and truck traffic. Diesel exhaust was the dominant source of total carbon (TC) and elemental carbon (EC) at the Azusa and downtown Los Angeles, CA, monit...
From recursions to asymptotics: Durfee and dilogarithmic deductions

We consider two dimensional arrays p(n,k) which count a family of partitions of n by a second parameter k, usually the number of parts. Such arrays frequently satisfy a finite recursion of a certain form, detailed in formula (2), as well as an asymptotic relation (*)p(n,k)=exp{ng(kn)(1+o(1))}. For such situations, we can characterize (Theorem 1) the function g(u) in terms of a polynomial associated with the recursion. We also identify (Theorem 2) a class of families which satisfy both the desired recursion and the limit law (*). For such families, the function g(u) is characterized by Theorem 1, and this resolves a number of conjectures made in an earlier work [Electron. J. Combin. 5 (1998) R32] concerning asymptotic enumeration of partitions by the size of their Durfee square. Finally, we study a family of partitions introduced by Andrews [Amer. J. Math. 91 (1969) 18-24]. These partitions do satisfy the desired recursion, but it is not known for sure whether they also satisfy the accompanying limit law. We prove (Theorem 3), conditionally on the conjectured limit law holding, some identities involving the dilogarithm. These identities are seen empirically, by calculation to many decimal places, to be true.
On the non-existence of global solutions to the Cauchy problem for semilinear parabolic equations and inequalities

We generalize and improve recent non-existence results for global solutions to the Cauchy problem for the inequality \(u_t \geqq \Delta u +|u|^q\) as well as for the equation ut = Δu + |u|q in the half-space \(\mathbb{R}_+^1\,\times\,\mathbb{R}^n,\; n\geqq 1\).
NMDA receptors and pain

NMDA Antagonists as Potential Analgesic Drugsedited by D.J.S. Sirinathsinghji and R.G. Hill, Birkhauser Verlag, 2002. Euro 118 (hardback) (186 pages) ISBN 3 7643 6011 9This slim volume contains a series of review articles dealing with the role of NMDA receptors in the transmission of nociceptive signals and the potential for the use of NMDA receptor antagonists as analgesics. The book begins with a useful and largely up-to-date overview of NMDA receptor pharmacology and molecular biology. Subsequent chapters deal with the distribution of NMDA receptors in the spinal cord, their role in nociception, and the effects of NMDA receptor antagonists. Particularly useful are the chapters dealing with the potential use of the subtype (NR2B)-selective antagonists and the effects on neuropathic pain of NMDA receptor antagonists that are currently used clinically.As with many multi-author volumes there is some redundancy in material, with similar background material (e.g. receptor classification and distribution) appearing in multiple chapters. The illustrations are of reasonable quality but rather sparse – more illustrations would have perhaps made the book more readily approachable.The book will most probably be useful to investigators working in the fields of pain and analgesia research, who want to learn about NMDA receptors and their role as analgesic targets. There is also something to offer researchers whose primary interest is glutamate receptors but who want to know about the role of these receptors in analgesia. For researchers in both camps, the book provides a useful collection of information concerning NMDA receptors, nociception and analgesia, which would otherwise require time spent in the library or on PubMed or similar websites to gather the information.
Gonadotropin Levels in Lactating Rats: Effect of Ovariectomy

The effect of suckling on synthesis and release of FSH and LH was investigated in intact and ovariectomized, lactating rats. Litter size was adjusted on Day 2 postpartum to 0, 3, 6 or 12 pups, and ovariectomies were performed at this time. Pituitary concentrations of FSH and LH were low on Day 2 and increased by Day 6. Pituitary FSH levels were greater in ovariectomized rats than in intact dams by Day 6 in rats with 0 and 3 pups and by Day 18 in dams nursing 6 pups. Pituitary LH concentrations were similar in all groups on Day 6, and the levels increased in ovariectomized rats with 0 and 3 pups by Day 12 and in dams nursing 6 pups by Day 18. Pituitary FSH and LH levels of intact and ovariectomized rats nursing 12 pups did not differ significantly during the first 18 days of lactation. Serum FSH and LH levels were elevated after ovariectomy; the rate and magnitude of these increases were diminished as litter size increased. Serum FSH and LH were elevated to detectable levels in all dams 12 hr after their p...
Detection of peri-implant bone changes with axial tomosynthesis

Tuned aperture computed tomography was used to assess bone defects at implant sites that are normally obscured in conventional periapical projections. Titanium implants were placed in incisor, premolar, and molar areas of an edentulous dry human mandible. The alveolar crest adjacent to each implant was circumferentially grooved with progressively larger round burs (no. 1/4 to no. 6). After each increment of bone removal, axial tuned aperture computed tomography slice images were produced. From these, digital subtraction images were generated with incremental and baseline slices. A panel of eight dentists reviewed randomized pairs of images that showed defects that differed by a single bur size. Images were masked to limit observation to mesial, distal, facial, or lingual regions. Observers accurately identified larger lesions in 76% of the unsubtracted tuned aperture computed tomography images and in 90% of the subtracted images. Logistic regression analysis suggested significant differences as a result of lesion size (p < 0.036) and imaging modality (p < 0.020).
The effects of removable partial dentures on abutment tooth mobility: A clinical study

M ost studies investigating the effects of removable partial dentures on abutment teeth have been performed in a laboratory setting. In vitro experiments simulate the periodontal ligaments, osseous structures, and residual ridges. Results obtained from in vitro researchI-* have given dentists insight into removable partial denture design, but still, some doubt exists as to how these prostheses function in clinical situations. Miihlemann”, 6 introduced the method of periodontometry to dental research. He accurately evaluated the mobility of teeth in the oral cavity by means of a dial gauge and force meter. The simplicity of his measuring instrument enabled him to obtain data from many patients. Fenner and co-workers’ measured tooth mobility changes during treatment with partial denture prostheses. Their results indicated that removable partial dentures produced significant tooth mobility changes. In this investigation, very little was done to modify the existing tooth contours. Rudd and O’Leary8 modified the existing research tools used by Miihlemann and performed a clinical study on partially edentulous patients. They reported that carefully planned removable guide plane prostheses were effective in stabilizing mobile teeth. Carlsson and associate9 found, in a longitudinal investigation of extension-base partial dentures, that the success of treatment was dependent more on biologic factors than on the design of the denture. No attempt was made in this study to measure tooth mobility. The following investigation was designed to study the effects of planned removable partial dentures on abutment tooth mobility in partially edentulous subjects with similar oral conditions.
Adaptive IIR filtering using stochastic filters

The authors present results illustrating the convex operating region of the stochastic filter which makes it possible to use the stochastic filter to model IIR (infinite impulse response) filters adaptively without concern about stability. Since the selection of the fixed filters in the stochastic filter determine its operation region, the fixed filters can be selected to cover most of the unit circle, or, if any prior information is available that reduces the region containing the unknown system poles, one can use that information in selecting the fixed filters. Computer simulations that generate an adaptive model for an autoregressive system are presented. >
Synergistic anticancer effects of combined γ-tocotrienol and celecoxib treatment are associated with suppression in Akt and NFκB signaling

Abstract The selective cyclooxygenase (COX)-2 inhibitor, celecoxib, and the vitamin E isoform, γ-tocotrienol, both display potent anticancer activity. However, high dose clinical use of selective COX-2 inhibitors has been limited by gastrointestinal and cardiovascular toxicity, whereas limited absorption and transport of γ-tocotrienol by the body has made it difficult to obtain and sustain therapeutic levels in the blood and target tissues. Studies were conducted to characterize the synergistic anticancer antiproliferative effects of combined low dose celecoxib and γ-tocotrienol treatment on mammary tumor cells in culture. The highly malignant mouse +SA mammary epithelial cells were maintained in culture on serum-free defined control or treatment media. Treatment effects on COX-1, COX-2, Akt, NFκB and prostaglandin E 2 (PGE 2 ) synthesis were assessed following a 3- or 4-day culture period. Treatment with 3–4 μM γ-tocotrienol or 7.5–10 μM celecoxib alone significantly inhibited +SA cell growth in a dose-responsive manner. However, combined treatment with subeffective doses of γ-tocotrienol (0.25 μM) and celecoxib (2.5 μM) resulted in a synergistic antiproliferative effect, as determined by isobologram analysis, and this growth inhibitory effect was associated with a reduction in PGE 2 synthesis, and decrease in COX-2, phospho-Akt (active), and phospho-NFκB (active) levels. These results demonstrate that the synergistic anticancer effects of combined celecoxib and γ-tocotrienol therapy are mediated by COX-2 dependent and independent mechanisms. These findings also suggest that combination therapy with these agents may provide enhanced therapeutic response in breast cancer patients, while avoiding the toxicity associated with high-dose COX-2 inhibitor monotherapy.
Interspersed repeated sequences in the African green monkey genome that are homologous to the human Alu family

Abstract The dominant family of interspersed repetitive DNA sequences in the human genome has been termed the Alu family. We have found that more than 75% of the lambda phage in a recombinant library representing an African green monkey genome hybridize with a human Alu sequence under stringent conditions. A group of clones selected from the monkey library with probes other than the Alu sequence were analyzed for the presence and distribution of Alu family sequences. The analyses confirm the abundance of Alu sequences and demonstrate that more than one repeat unit is present in some phages. In the clones studied, the Alu units are separated by an average of 8 kilobase pairs of unrelated sequences. The nucleotide sequence of one monkey Alu sequence is reported and shown to resemble the human Alu sequences closely. Hence, the sequence, dispersion pattern, and copy number of the Alu family members are very similar in the African green monkey and human genomes. Among the clones investigated were two that contain segments of the satellite DNA term alpha-component joined to non alpha-component DNA. The experiments indicate that in the monkey genome Alu sequences can occur close to regions of alpha-component DNA.
Comparison of pre- and post-combustion carbon removal

Conventional approaches to reduce CO{sub 2} emissions, including fuel switching among fossil fuels, renewables, nuclear, end-use conservation, and increased efficiency, nearly all lead to reduction in coal use. Carbon removal technologies along have the potential to allow continued use of coal. All approaches must compete economically, technically, and environmentally for market share within the context of the total energy system. MARKAL, a dynamic energy systems model, was used to simulate this competition through 2025 for the US energy system. Three carbon removal technologies were evaluated: CO{sub 2} scrubbing from coal-fired power plant flue gas, CO{sub 2} separation during coal gasification, and carbon separation in the Hydrocarb process. CO{sub 2} was sequestered in depleted gas wells and the deep ocean, and solid carbon in depleted coal mines. All three technologies evaluated offer a more cost-effective path to CO{sub 2} emission reduction than the reference case. Moreover, the ability of pre-combustion methods of carbon removal can be combined with producing motor fuels as well as electric power fuels, a combination that provided greater opportunity for carbon removal.
The Effect of Various Substituted p-Benzoquinones on Electron Transport in Spinach Chloroplasts

Four different substituted p-benzoquinones resembling the natural chloroplast quinone, plastoquinone A, in structure [2,3-dimethyl-5-bromo-6-n-octadecylmercapto-l,4-benzoquinone (compound 6712) ; 2,3-dimethyl-5-n-propylamino-l,4-benzoquinone (compound 671 1) ; 2,3-dimethyl-5oleylamino-l,4-benzoquinone (compound 671 0) ; and 2,3-dimethyl-5-n-hexadecylamino-l,4-benzoquinone (compound 6709)] were tested for their effect on electron transport in spinach chloroplasts. 2,4-Dimethyl-p-benzoquinone reduction by photosystem I1 was inhibited best by compound 6712 (ZSO = 27 pg/ml, or 54 pM conc.), followed by compounds 6709 and 6710 (150 = 63 pg/ml or 125 yM conc. of either); compound 6711, a short-chain analog, was least effective (150 = 75 pg/ml or 0.3 mM conc.). (150 is the dose which inhibits 50%.) Inhibition by compounds 6712 and 6710 could be reversed by the addition of exogenous plastoquinone A indicating that these two benzoquinones interfered with the reduction of plastoquinone A before the well-known 2,Sdibromo3-methyl-6-isopropyl-p-benzoquinone inhibition site between the two photosystems (Trebst and Reimer, 1973, 2. Naturforsch. 28c, 710). A negative synergistic effect between exogenous plastoquinone A and the four benzoquinones studied was observed on silicomolybdate reduction by photosystem I1 in the presence of 3-(3,4-dichloropheny1)-1,1 -dimethylurea. Another benzoquinone inhibition site, not reversed by exogenous plastoquinone A, occurred in photosystem I on the ascorbate plus N,N,N',N-tetramethyl-p-phenylenediamine + methylviologen pathway. The relevance of these benzoquinone inhibition sites to photosynthetic electron transport is discussed.
Thermo-dynamic characteristics of NITINOL-reinforced composite beams

Abstract The dynamic characteristics of flexible composite beams are controlled by heating sets of shape memory alloy (NITINOL) fibers embedded along the neutral axes of these beams. The activation of the shape memory effect of the fibers increases the elastic energy and enhances the stiffness of the composite beams. With such capabilities, the vibration modes of the beams can be tailored and shifted away from the excitation frequency band in order to avoid undesirable vibrations. Emphasis is placed, in the present study, on the effect of intentional electrical heating of a selected subset of the NITINOL fibers on the overall dynamics of the beams. The effect of the associated thermal energy propagating through the composite on the unintentional thermal activation of additional subsets of the NITINOL fibers is accounted for. Such an effect is not only significant but also essential to the thorough understanding of the operation of NITINOL-reinforced composites. Finite element models are developed to describe the interaction between the thermal and dynamic characteristics of the NITINOL composites as well as the interaction between the intentional and unintentional activation of the NITINOL fibers. The models are experimentally validated and close agreement is obtained between the theoretical predictions and the experimental results. The mathematical models and procedures described in this paper provide an invaluable means of predicting realistic performance of NITINOL-reinforced composites.
Vertical Oscillatory Motion of a Single Colloidal Particle Adjacent to an Electrode in an ac Electric Field

The vertical motion of a levitated colloidal particle immersed in aqueous solution, located near an electrode, and subjected to an alternating electric field normal to the electrode was recorded using total internal reflection microscopy. The particle's height was sinusoidal in time during the portion of the cycle above its average height; during the remainder of the cycle, however, hydrodynamic hindrance arising from the particle's proximity to the electrode did not allow it to descend below the average height with the same amplitude as above. The particle's height averaged over a full cycle exhibited a minimum in its frequency and voltage dependences in potassium hydroxide but increased monotonically with frequency in sodium bicarbonate. The phase between the response of the particle and the applied electric field varied significantly with frequency. Both the profoundly different response in potassium hydroxide and sodium bicarbonate and the significant variation in phase angle with frequency are not ex...
Academic and Behavioral Characteristics of Learning Disabled Children and Average Achievers: Longitudinal Studies:

Longitudinal research in the area of learning disabilities has been lack- ing for some time. The study reported here is an attempt to chart the development of newly identified LD children over the early elementary school years while they are receiving LD services in the public school. This paper includes initial behavioral and academic data for a large sample of 6- and 7-year-old LD and nor- mally achieving students, and charts the progress of about half the children over a 3-year period using teacher rating scales, a classroom observational system, and an achievement test. Results of the study over the three years show that LD child- ren fall progressively further behind their normal peers in reading comprehension. In math, they stay relatively the same distance below their peers. The LD subjects' behavior relative to that of their peers is suboptimal for classroom learning in the first year of the study, with less on-task and more off-task behavior - a pattern which continues over the three-year period. This portrait of learning disabled children suggests that learning disabilities are difficult to remediate, and that we may need to rethink our pattern of services to these students if we want them to function successfully in the regular classroom.
Molecular characterization of the klebicin B plasmid of Klebsiella pneumoniae.

The nucleotide sequence of a bacteriocin-encoding plasmid isolated from Klebsiella pneumoniae (pKlebB-K17/80) has been determined. The encoded klebicin B protein is similar in sequence to the DNase pyocins and colicins, suggesting that klebicin B functions as a nonspecific endonuclease. The klebicin gene cluster, as well as the plasmid backbone, is a chimera, with regions similar to those of pore-former colicins, nuclease pyocins and colicins as well as noncolicinogenic plasmids. Similarities between pKlebB plasmid maintenance functions and those of the colicin E1 plasmid suggest that pKlebB is a member of the ColE1 plasmid replication family.
Multiparameter averaging and inverse spectral problem for anharmonic oscillators in Rn

This paper extends 1-D results of [1–3] on Inverse Spectral Problems for perturbations B(χ) ∼ |χ| −αV (χ) of the 1-D harmonic oscillator A = 12 (−∂2+ ∂2), to multidimensional oscillators on n. We prove the direct spectral result for operators L = A+B, which yields asymptotics of eigenvalues of L in terms of potential B. The proof requires new averaging methods developed in the paper, and further elaboration of the author's symbolic calculus [1–3]. After the direct result is established we turn to the inverse problem and outline some partial results, as well as open questions and the future lines of development.
Fundamental concepts of microcomputer graphics

Abstract The purpose of this article is to discuss some of the fundamental concepts and techniques of microcomputer graphics. It begins with a brief background of computer graphics. There is a discussion of display technology and two associated image development algorithms. These are typically a part of the graphics language, require little attention from the graphics programmer, and provide the foundation on which all graphic images are developed. It concludes with a presentation of fundamental mathematical and programming technique.
METHODS AND MORPHEMES IN SECOND LANGUAGE ACQUISITION RESEARCH1

Recent morpheme studies of second language acquisition are methodologically difficult to interpret and the validity of some conclusions is questionable. The present study sought to ascertain (a) whether the morpheme order obtained using an elicitation instrument resembles the order of morphemes obtained from spontaneously collected second language acquisition speech data, and (b) whether the cross-sectional and longitudinal research findings in second language acquisition research are comparable. The results of the study raise serious questions about the validity of cross-sectional studies of second language acquisition based on instrument-elicited morpheme data. The analysis of spontaneous data examined longitudinally suggests that such data may provide richer insights into the second language acquisition process.
Antiferromagnetic resonance and the H-T phase diagram of KMnCl3ṡ2H2O

Abstract Antiferromagnetic resonance and phase boundary measurements on KMnCl 3 ṡ2H 2 O are presented and discussed in terms of a possible model of two weakly coupled two-sublattice antiferromagnets.
Solar circumstances at the time of the cosmic ray increase on January 28, 1967

Solar circumstances have been evaluated for January 28, 1967, the date of an observed ground level enhancement of cosmic rays which was not preceded by observation of a suitably great Hα flare. On the visible solar hemisphere, a bright subflare at S23° E19° occurred in appropriate time association with the cosmic ray event, and was accompanied by weak X-ray enhancement and radio frequency emission. If this flare, alone, or in combination with other minor flares observed on the visible hemisphere on January 28 was the source of the energetic cosmic rays recorded on that date, then current thinking regarding the characteristics of cosmic ray flares must be modified.
Poliovirus Escape from RNA Interference: Short Interfering RNA-Target Recognition and Implications for Therapeutic Approaches

Short interfering RNAs (siRNAs) directed against poliovirus and other viruses effectively inhibit viral replication. Although RNA interference (RNAi) may provide the basis for specific antiviral therapies, the limitations of RNAi antiviral strategies are ill defined. Here, we show that poliovirus readily escapes highly effective siRNAs through unique point mutations within the targeted regions. Competitive analysis of the escape mutants provides insights into the basis of siRNA recognition. The RNAi machinery can tolerate mismatches but is exquisitely sensitive to mutations within the central region and the 3' end of the target sequence. Indeed, specific mutations in the target sequence resulting in G:U mismatches are sufficient for the virus to escape siRNA inhibition. However, using a pool of siRNAs to simultaneously target multiple sites in the viral genome prevents the emergence of resistant viruses. Our study uncovers the elegant precision of target recognition by the RNAi machinery and provides the basis for the development of effective RNAi-based therapies that prevent viral escape.
Structural and functional analysis of the sarcoglycan-sarcospan subcomplex

Sarcospan is a component of the dystrophin-glycoprotein complex that forms a tight subcomplex with the sarcoglycans. The sarcoglycan-sarcospan subcomplex functions to stabilize α-dystroglycan at the plasma membrane and perturbations of this subcomplex are associated with autosomal recessive limb-girdle muscular dystrophy. In order to characterize protein interactions within this subcomplex, we first demonstrate that sarcospan forms homo-oligomers within the membrane. Experiments with a panel of site-directed mutants reveal that proper structure of the large extracellular loop is an important determinant of oligo formation. Furthermore, the intracellular N- and C-termini contribute to stability of sarcospan-mediated webs. Point mutation of each cysteine residue reveals that Cys 162 and Cys 164 within the large extracellular loop form disulfide bridges, which are critical for proper sarcospan structure. The extracellular domain of sarcospan also forms the main binding site for the sarcoglycans. We propose a model whereby sarcospan forms homo-oligomers that cluster the components of the dystrophin-glycoprotein complex within the membrane.
Effect of immobilization on sole-plate and background cholinesterase of rat skeletal muscle

Abstract The observation that the cholinesterase activity (ChE) of muscle decreases more profoundly during denervation atrophy than during non-neurogenic (disuse) atrophy has led to the suggestion that the nerve specifically regulates muscle ChE. However, denervation results in a flaccid paralysis in which the muscles are not used; therefore it is not justifiable to consider denervation and disuse atrophy as wholly separate entities. The present study was undertaken to investigate separately the changes in sole-plate and background ChE during disuse and denervation atrophy in order to determine whether the nerve specifically influences ChE at either of these sites. Disuse atrophy of the rat's soleus muscle was produced by internal fixation of the knee and ankle joints and denervation atrophy by transection of the sciatic nerve. With regard to protein loss, immobilization plus denervation produced greater atrophy (31.7%) than did immobilization alone (19.9%). The decrease in background ChE after each of these operations (35.6 and 22.4% respectively) was not significantly different from the loss in protein. Sole-plate ChE, on the other hand, exhibited a large decrease (53.4%) in response to denervation plus immobilization but was little altered by immobilization alone (8.7% decrease). Although the question of the specificity of the neural influence on background ChE remains unresolved by these results, it is concluded that the nerve specifically regulates ChE at the sole plate.
Planning and developing a diagnostic imaging center

The convergence of an aging population, new technology, and an increasing number of clinical applications and reimbursements has created a favorable environment for ambulatory imaging centers. From a patient's perspective, features such as easy access, parking, appointment availability, and a setting that caters to outpatients are attractive compared with the hospital environment. Before embarking on a venture, the execution of a careful, thorough planning process, from the inception of the idea to the opening, is vital to success. This article provides guidance on the process by discussing the process of determining whether a project is feasible; developing a business plan that will measure potential success; locating, financing, and planning space; contractor selection and project management; and planning operations.
Can screening items identify surgery patients at risk of limited health literacy

Background Health literacy skills (HLS) have been shown to have a major impact on patient outcomes. To identify patients with limited or marginal HLS, the accuracy of three established screening items were examined. Materials and methods We studied English-speaking adults (≥21 years) attending a university-based vascular surgery clinic. Structured interviews were conducted to assess sociodemographic characteristics, screening items, and HLS. Area under the receiver operating characteristic (AUROC) curves were plotted to assess the discriminatory capacity of each screening item in detecting patients with limited/marginal HLS. Results One hundred patients agreed to enter the study and met inclusion criteria. The mean age was 62.0 ± 12.9; 65 were female; 96 were Caucasian; and 32 had not completed high school. The three screening items were effective in detecting patients with limited ( n = 18) or marginal ( n = 21) HLS. “How often do you have someone (like a family member, friend, or hospital worker) help you read hospital materials?” (AUROC of 0.83; 95% confidence interval [CI] = 0.73, 0.92), “How often do you have problems learning about your medical condition because of difficulty understanding written information?” (AUROC of 0.77; 95% CI = 0.67, 0.86), and “How confident are you filling out medical forms by yourself?” (AUROC of 0.76; 95% CI = 0.66, 0.86) were effective in detecting those with limited/marginal HLS skills. Conclusions Our findings provide further evidence of the clinical usefulness of these screening items for detecting inadequate HLS in this patient population. Surgeons should consider administering these easy screening items to identify patients at greatest risk of limited or marginal HLS.
Experimenting with tail-recursion and simulating coroutines

The efficiency of tail recursion and the simplicity of its removal makes some people wonder why we cannot transform all recursive definitions to this form? Clearly, the usual trick of introducing a new variable and using it as an accumulator to hold the intermediate results during the winding phase does not always work. But, by trying to generalize this technique to primitive recursion one can easily find a sufficient condition which makes it work. The class of functions satisfying this condition may be interesting also on its own. A direct generalization of this function class for mutual recursion is fairly straightforward.
Internal friction in the ultrafast folding of the tryptophan cage

Abstract Protein folding is a diffusional process, and the speed of folding is controlled by the frictional forces that act on the polypeptide chain. Several previous studies have suggested that the bulk viscosity of the solvent is the only important source of friction in folding reactions. By contrast, our studies of the folding dynamics of the Tryptophan Cage, a small, ultrafast-folding protein, show clear evidence for additional frictional forces that are independent of the solvent viscosity. The nature of this internal friction appears qualitatively different for the folding vs. unfolding reactions. We expect that this phenomenon could significantly influence the rate of many folding processes that proceed on sufficiently fast (∼μs) time scales. In particular, it may limit folding speeds to values substantially slower than the diffusion limits estimated from simple contact-formation studies in polypeptides.
Centrifugal distortion in planar molecules

Abstract The rotational distortion of a general asymmetric top molecule is described by six rotational distortion constants which are functions of nine constants appearing in the first-order Hamiltonian for the nonrigid rotor. In this paper it is shown that for the case of a planar asymmetric top molecule these nine constants reduce to four, so that the centrifugal distortion of a planar asymmetric top molecule can be described by four constants rather than the usual six. It is also shown for planar symmetric top molecules that only two constants are required to described the centrifugal distortion effects, rather than the usual three.
Transforming growth factor-β alters differentiation in cultures of avian neural crest-derived cells: Effects on cell morphology, proliferation, fibronectin expression, and melanogenesis

Abstract Neural crest cell differentiation is responsive to a variety of extrinsic signals that include extracellular matrix (ECM) molecules and growth factors. Transforming growth factor-β (TGF-β) has diverse, cell type-specific effects, many of which involve regulation of synthesis of ECM molecules and their cell surface receptors. We are studying both separate and potentially interrelated influences of ECM and growth factors on crest differentiation and report here that TGF-β alters several aspects of crest cell behavior in vitro . Clusters of quail neural crest cells were cultured in the presence and absence of 400 p M TGF-β1 and examined at 1, 3, and 5 days. When examined at 5 days, there was a dramatic decrease in the number of melanocytes in treated cultures, regardless of the onset or duration of TGF-β treatment. With continuous TGF-β treatment, or with treatment only during crest cluster formation on explanted neural tubes, many cells increased in area, becoming extremely flat. These changes were evident beginning on Day 3. While quantitative analyses of video images documented the size increase, several aspects of motility were relatively unchanged. Synthesis of fibronectin (FN) by approximately 11% of cells on Day 3 and 31% of cells on Day 5 was demonstrated by immunocytochemistry and was associated with a sixfold increase in FN mRNA by Day 5. Experiments which correlated FN immunoreactivity with incorporation of bromodeoxyuridine suggested that the population of large, flat, FN-positive cells did not proliferate selectively and that there was a slower rate of proliferation in TGF-β-treated cultures than in untreated cultures. The large FN-immunoreactive cells resemble cells derived from cepalic neural crest and raise interesting questions concerning potential roles for TGF-β in regulating crest differentiation in vivo .