cssi/SciSciGPT-SciSciNet huggingface dataset:
Properties of L-tyrosine based polyphosphates pertinent to potential biomaterial applications

Abstract Since their introduction by Kohn and Langer et al. in 1984, l -tyrosine based ‘pseudo’ poly(amino acids) have undergone extensive research in the area of polymeric biomaterials. Starting from l -tyrosine based diphenolic monomers, polyiminocarbonates, polycarbonates and polyarylates have been developed by Kohn and co-workers and are being investigated for potential orthopedic biomaterial applications. Mao et al. have reported development of l -tyrosine based polyphosphates and polyphosphonates in a patent, however, detailed structural and physico-chemical characterization studies on such polymers have not been reported yet. For the purpose of the current paper, using a novel solid phase process for synthesis of l -tyrosine based diphenolic monomers and adapting the polymerization process described by Mao et al., l -tyrosine based polyphosphates were developed and investigated for their pertinent bioengineering properties. The properties investigated consist of chemical solubility, hydrophilicity and hydrolytic degradation. The results of this investigation are crucial to validate further investigation of biomaterial applications of these polymers.
Charting stages of preservice teacher development and reflection in a multicultural community through dialogue journal analysis

Abstract The purpose of this study was to examine programmatic and personal dimensions that interact to shape a future teacher's beliefs and practices. The study charted stages of preservice teacher development through dialogue journal case study analysis of eight students representing divergent academic disciplines and cultural biographies. These students kept dialogue journals with their professors throughout their program. The preservice teachers passed through three discernible stages: (a) introductory, (b) intermediate, and (c) immersion. Dialogue journals written at these three stages demonstrated that preservice teachers' personal biographies interact with the other dimensions that influence preservice teachers including discipline subculture and the quality of preservice experience in the classroom to help or impede their ability to negotiate and then to reflect on the competing demands of becoming a teacher. Implications for teacher education programs and future research emerged from the case study analyses.
Punishment of observing by a stimulus associated with the lower of two reinforcement frequencies

Abstract Three pigeons were used to investigate the effects of a stimulus associated with the lower of two reinforcement frequencies on the response producing it. In a three-key chamber, pecking the center key produced grain on alternating variable-interval schedules with mean durations of 2 min or 30 sec. Initially, green illumination of the keys accompanied the more favorable (30-sec) schedule and red accompanied the less favorable (2-min) schedule. Then the keys remained yellow unless the bird pecked one of the side (observing) keys to produce the discriminative stimuli for a 30-sec period. Subsequently, when red was withheld as a possible consequence of pecking a particular side key, the rate on that key increased; when red was restored, the observing rate decreased. Thus the stimulus associated with less frequent reinforcement had a punishing effect on the behavior producing it. When green was withheld on one of the side keys and the other key produced both colors, observing behavior was not maintained on the red-only key, but was maintained on the key that produced both colors.
Synthetic Lethality with the dut Defect in Escherichia coli Reveals Layers of DNA Damage of Increasing Complexity Due to Uracil Incorporation

Synthetic lethality is inviability of a double-mutant combination of two fully viable single mutants, commonly interpreted as redundancy at an essential metabolic step. The dut-1 defect in Escherichia coli inactivates dUTPase, causing increased uracil incorporation in DNA and known synthetic lethalities [SL(dut) mutations]. According to the redundancy logic, most of these SL(dut) mutations should affect nucleotide metabolism. After a systematic search for SL(dut) mutants, we did identify a single defect in the DNA precursor metabolism, inactivating thymidine kinase (tdk), that confirmed the redundancy explanation of synthetic lethality. However, we found that the bulk of mutations interacting genetically with dut are in DNA repair, revealing layers of damage of increasing complexity that uracil-DNA incorporation sends through the chromosomal metabolism. Thus, we isolated mutants in functions involved in (i) uracil-DNA excision (ung, polA, and xthA); (ii) double-strand DNA break repair (recA, recBC, and ruvABC); and (iii) chromosomal-dimer resolution (xerC, xerD, and ftsK). These mutants in various DNA repair transactions cannot be redundant with dUTPase and instead reveal “defect-damage-repair” cycles linking unrelated metabolic pathways. In addition, two SL(dut) inserts (phoU and degP) identify functions that could act to support the weakened activity of the Dut-1 mutant enzyme, suggesting the “compensation” explanation for this synthetic lethality. We conclude that genetic interactions with dut can be explained by redundancy, by defect-damage-repair cycles, or as compensation.
An experimental and modelling investigation of gas mixing in bubbling fluidized beds

Abstract Gas mixing in bubbling fluidized beds has been modelled, within the framework of the three-phase backmixing formulation, taking the influence of the circulation patterns of solids into account. It is shown that the inclusion of the solids movement patterns leads to axial dispersion of the gas in the dense phase for intermediate and high U 0 U mf . If the dispersion is assumed to take place on a length scale of the size of the bubble, the dispersion coefficient can be estimated from a theoretical basis. Tracer pulse experiments have been performed by injecting methane gas in a 0.2 m diameter fluidized bed containing glass ballotini to obtain residence time distributions of the non-adsorbable tracer. The data from these experiments, and from other experiments reported in the literature, compare well with model calculations. Visible bubble flow has been identified as an important parameter in the mixing of gas in bubbling fluidized beds. It is shown that if the voidage in the cloud and wake phase is assumed to be the same as that in the dense phase, then the variation of the visible bubble flow cannot be specified independent of the slip velocity between the gas and the solids in the dense phase. Possible mechanisms for change in visible bubble flow with height above the distributor and their consequences on gas mixing are discussed.
Job-Sharing Couples In Academia: Career And Family Lifestyles

The purpose of this study was to investigate careers and family lifestyles of 20 job-sharing couples in faculty positions at 12 colleges. Interviews conducted with both spouses and questionnaires administered to individual partners provided information about the couples' reasons for becoming involved in job sharing, conditions of their employment, their division of professional and household labor, their satisfaction with the job-sharing arrangement, and their future career plans. Competitive job market conditions and the desire for improved lifestyles were major factors influencing the decision to share a position. Couples were employed by their institutions as teams with one shared contract or as regular, part-time workers with independent contracts. Spouses sharing one position con tributed an average of 90 hours per week to professional activities. A majority of the couples were involved in egalitarian family relationships characterized by cooperation in childrearing and domestic labor. Lifestyle flexibility and empa thetic spousal support were perceived as major advantages of job sharing, whereas low family income and the potential for institutional exploitation were considered to be major drawbacks. Three-quarters of the couples planned to continue job sharing in the following academic year, but only one quarter ex pected to maintain this arrangement for five years. Most couples viewed job sharing as a temporary work option rather than as a permanent lifestyle.
E-serial Titles That Disappear

Abstract CONSER (Cooperative Online Serials Program) members are currently dealing with the problem of how to catalog electronic journals that over time do not retain their titles on earlier issues. The dilemma for catalogers is whether to use the successive entry rules of AACR2 (Anglo-American Cataloging Rules) for serials or to apply the latest entry approach used for integrating resources. CONSER members are currently working on a discussion paper that will weigh the pros and cons of successive and latest entry to be presented at the CONSER Operations Committee meeting in May 2002. Discussion of the issues will provide the background for a Library of Congress Rule Interpretation. Serials Review 2002; 28:222–224.
Ca2+-Induced Current Oscillations in Rabbit Ventricular Myocytes

Abstract Transient currents are activated by spontaneous Ca2+ oscillations in rabbit ventricular myocytes. We investigated the ionic basis for these transient currents under conditions in which K+ currents would be expected to be blocked. Holding cells under voltage clamp at positive potentials leads to a rise in intracellular Ca2+ via reversal of the Na+-Ca2+ exchanger and subsequently to the initiation of spontaneous Ca2+ transients, presumably from a Ca2+-overloaded sarcoplasmic reticulum. The current transients associated with these Ca2+ transients reversed at about +10 to +15 mV under conditions of approximately symmetrical Cl−. In the absence of Cl−, this current was inward at all potentials examined over the range from −88 to +72 mV, consistent with a Na+-Ca2+ exchanger current. In the absence of Na+, the repetitive spontaneous Ca2+ transients could be initiated by a brief train of depolarizations to activate the inward Ca2+ current. Under such conditions, the current was found to reverse at −3 mV when the equilibrium potential of Cl− (ECl) was −2 mV, and the reversal potential shifted to −32 mV when internal Cl− was lowered, to make ECl −33 mV. Thus, in the absence of Na+, it appears that the current is exclusively a Ca2+-activated Cl− current. There is no evidence to indicate the presence of a Ca2+-activated cationic conductance. Further, our results demonstrate that the Ca2+-activated Cl− conductance can carry inward current at potentials more negative to ECl in rabbit ventricular myocytes and is therefore likely to contribute to the arrhythmogenic delayed afterdepolarizations that occur in Ca2+-overloaded cells.
Interleukin-1β-induced growth enhancement of Staphylococcus aureus occurs in biofilm but not planktonic cultures

Abstract Staphylococcus aureus causes recalcitrant infections and forms resistant biofilms. Mechanisms of biofilm resistance to host defenses may include changes in gene expression that confer responsiveness to chemical mediators. In earlier studies fresh clinical isolates responded to inflammatory cytokines, but responsiveness was lost after multiple in vitro passages [Meduri et al. Cytokines IL-1β, IL-6, and TNF-α enhance the In vitro growth of bacteria. Am J Respir Crit Care Med 1999;160:961–7]. Since biofilms more closely resemble in vivo growth and are implicated in recalcitrant infections, we hypothesized that biofilms, but not planktonic cells, would respond to cytokines. Biofilms were induced by ethanol in S. aureus ATCC 12600. Biofilms treated with 2 ng/mL interleukin-1β (IL-1β) for 6 h contained 2.5-fold more cells than untreated biofilms, but no growth-enhancement occurred in planktonic cultures. As determined by flow cytometry, IL-β bound to 63.1% of biofilm cells, but only 11.2% of planktonic cells. Our results provide evidence of a differential response of biofilm and planktonic bacteria to chemical mediators, and suggest that biofilm bacteria may evade host defenses by growing more rapidly in response to the inflammatory mediators released by activated host defense cells.
Submacular scar excision in age-related macular degeneration

Disciform scars secondary to age-related macular degeneration were surgically removed in three patients. Postoperative visual acuity improved minimally in one case and decreased in the other two cases. The results suggest further investigation is needed with possible modifications of our technique for future studies.
Why White, Not Keynes? Inventing the Postwar International Monetary System

The international monetary system is largely the product of negotiations during World War II between U.S. and U.K. officials, led respectively by Harry Dexter White and John Maynard Keynes. The design of the system, especially the International Monetary Fund, reflects the U.S. plan much more than the British. That outcome resulted not only from the superior economic position of the United States but also from differences between White's and Keynes's views on key issues. Examination of White's economic papers shows that he was more multilateral than Keynes and placed a higher priority on monetary discipline.
Floral primordia-targeted ACS (1-aminocyclopropane-1-carboxylate synthase) expression in transgenic Cucumis melo implicates fine tuning of ethylene production mediating unisexual flower development

Floral primordia-targeted expression of the ethylene biosynthetic gene, ACS , in melon suggests that differential timing and ethylene response thresholds combine to promote carpels, inhibit stamens, and prevent asexual bud formation. Typical angiosperm flowers produce both male and female reproductive organs. However, numerous species have evolved unisexuality. Melons (Cucumis melo L.) can produce varying combinations of male, female or bisexual flowers. Regardless of final sex, floral development begins with sequential initiation of all four floral whorls; unisexuality results from carpel or stamen primordia arrest regulated by the G and A loci, respectively. Ethylene, which promotes femaleness, is a key factor regulating sex expression. We sought to further understand the location, timing, level, and relationship to sex gene expression required for ethylene to promote carpel development or inhibit stamen development. Andromonoecious melons (GGaa) were transformed with the ethylene biosynthetic enzyme gene, ACS (1-aminocyclopropane-1-carboxylate synthase), targeted for expression in stamen and petal, or carpel and nectary, primordia using Arabidopsis APETALA3 (AP3) or CRABSCLAW (CRC) promoters, respectively. CRC::ACS plants did not exhibit altered sex phenotype. AP3::ACS melons showed increased femaleness manifested by gain of a bisexual-only phase not seen in wild type, decreased male buds and flowers, and loss of the initial male-only phase. In extreme cases, plants became phenotypically hermaphrodite, rather than andromonoecious. A reduced portion of buds progressed beyond initial whorl formation. Both the ACS transgene and exogenous ethylene reduced the expression of the native carpel-suppressing gene, G, while elevating expression of the stamen-suppressing gene, A. These results show ethylene-mediated regulation of key sex expression genes and suggest a mechanism by which temporally regulated ethylene production and differential ethylene response thresholds can promote carpels, inhibit stamens, and prevent the formation of asexual buds.
Tracing along-strike structural continuity in the Neoproterozoic Allaqi-Heiani Suture, southern Egypt using principal component analysis (PCA), fast Fourier transform (FFT), and redundant wavelet transform (RWT) of ASTER data

Abstract We have used the visible and near infrared (VNIR) and short wave infrared (SWIR) bands of the advanced space-borne thermal emission and reflectance radiometer (ASTER) to trace along-strike structures in the ophiolite-decorated Neoproterozoic Allaqi-Heiani Suture in southern Egypt. The suture is E-trending in the west, changes to N-trending in its central part, and E-trending further east. The western part of the suture is defined by a fold and thrust belt dominated by an autochthon in the south followed by a southern, central and northern allochthons that were emplaced top-to-the-south. Tracing along-strike structures in the Allaqi-Heiani Suture has been a challenging task due to structural complexity and change of structural style. Principal component analysis (PCA), fast Fourier transform (FFT), and redundant wavelet transform (RWT) are used to identify ophiolite components such as talc carbonate schist, gabbro, and serpentinite as well as Neoproterozoic ductile structures to trace along-strike continuation in the Allaqi-Heiani Suture. (1) The PCA is performed on the 9 × 9 covariance matrix of the ASTER VNIR and SWIR bands. PC5 is selected because the ophiolite components and the Neoproterozoic ductile structures are best emphasized. (2) The FFT is performed on PC5 to reduce noises and mosaicking boundaries of the ASTER scenes. (3) The RWT is performed to enhance the contrast between ophiolite components and the surrounding rock types. This work helped in tracing structures along the Allaqi-Heiani Suture and revealed structural features that have not been identified before: (1) Some folds associated with the S-verging fold and thrust belts are periclinal folds that might be associated with nappe emplacement. (2) Truncation of structures associated with the S-verging fold and thrust belts occurs along NNW-trending sinistral strike-slip shear zones that swing at their extreme ends to become parallel to the truncated structures. (3) Presence of N-trending folds close to the NNW-trending sinistral strike-slip shear zones. (4) Presence of N- and NE-trending brittle faults younger than the Neoproterozoic ductile structures. Nappes identified in the west are traced into the central part of the suture allowing for subsequent modification by younger structures. The difference in structural styles along the suture might be due to development of frontal and lateral ramps along the traces of the orogen front. This was followed by superimposition of E–W shortening to produce N-trending folds that are localized close to the lateral ramps. Subsequently, N- and NE-trending brittle faults were developed and deformed early Neoproterozoic ductile structures.
Stereospecificity of opiate-stimulated GTPase activity in brain.

Abstract Low Km GTP hydrolysis in rat brain is stimulated in a concentration-dependent manner by the opiate levorphanol but not by its inactive anantiomer dextrorphan. This finding demonstrates the stereospecificity of opioid-stimulated GTPase in brain. The mu-selective ligands levorphanol and DAGO are less potent and less efficacious than etorphine or DALA, suggesting that delta opioid receptors are regulated by the GTP binding protein Ni in brain.
Nonintegrability of the Størmer problem

Abstract Let KM be the Hamiltonian obtained by reducing the nonrelativistic Hamiltonian H of the Stormer problem w.r. to the rotational symmetry about the magnetic dipole direction and fixing M = eM3 at a nonzero value, e denoting the sign of the particle charge and M3 the angular momentum component along this direction. Our main result is that KM does not possess for any M≠0 a global real analytic integral of KM, functionally independent of KM, and having a (single valued) meromorphic extension to a connected neighborhood of a suitable complexified nonequilibrium phase curve of KM. This implies that H has no global real analytic integral in involution with M3, functionally independent of H and M3, and extendable meromorphically to the complexified phase space of H. These properties of KM and H immediately entail similar nonintegrability properties for their relativistic analogues. The nonintegrability of KM for M ≠ 0 was proved by using Churchill and Rod's version of Kovacic's algorithm.
A very stable electrode system for recording human scalp potentials with direct-coupled amplifiers

Abstract Electrochemical factors involved in DC recordings are presented. Described is an electrode system which uses long flexible tubes to separate the metal-electrolyte interface of an electrode from the electrolyte-skin interface. Using commercially available Ag/AgCl skin potential electrodes, the system gave less than 0.5 μV/h drift occurring at each metal-electrolyte interface. The stability of the electrode bias potential is unaffected by connecting the bridge tubes to the subject or by other disturbances that occur during recording. In 1 h recordings from four subjects, the total measured potential changed at an average rate of 9 μV/min—a five fold improvement over previously described electrodes.
Temperature, Nitrogen and Light Effects on Hybrid Bermudagrass Growth and Development

'Tifdwarf' bermudagrass [C. dactylon (L.) Pers. x C. transvaalensis Burtt-Davy] is one of the most widely used cultivars on golf course putting greens in the southern USA because of its superior putting green quality. This study evaluated the effects of photosynthetic photon flux density (PPFD), temperature, and nitrogen fertilization on growth and development of Tifdwarf bermudagrass. In controlled environment studies, increasing N increased bermudagrass internode length, leaf length, and shoot weights. Increasing N had no significant effect on the chronological appearance rate of successive leaves and axillary buds. The phyllochron was positively correlated with day/night temperature. The internode and leaf length were greatest at the 27/19 degrees C treatment and least at the 35/27 degrees C treatment. Internode length increased from 20 to 40 mm as the PPFD decreased from 975 to 300 micromol m(-2) s(-1) at 27/19 degrees C but only increased from 10 to 22 mm long at 35/27 degrees C. Leaf lengths responded similarly. Leaf and internode length were greater at low than at high day/night temperatures regardless of incident light. The alteration in growth form occurred within 3 to 4 d of treatment initiation. Results indicated that temperature as well as light levels regulated expression of dwarfness in Tifdwarf bermudagrass. In regions that typically have long periods with daytime temperatures of 27 degrees C or less and a PPFD of 600 micromol m(-2) s(-1) or less, the growth form of Tifdwarf bermudagrass may change dramatically, resulting in plants with longer internode spacings and longer leaves. Because of this change in growth form, one may expect faster coverage from newly planted sprigs and faster recovery from disruptive cultural activities when the daytime temperatures are 27 degrees C or less as compared with periods when the daytime temperatures are 30 degrees C or above and the PPFD is >1000 micromol m(-2) s(-1) as is typical of summer in southern climates.
Cellular factors required for protection from hyperoxia toxicity in Saccharomyces cerevisiae

Prolonged exposure to hyperoxia represents a serious danger to cells, yet little is known about the specific cellular factors that affect hyperoxia stress. By screening the yeast deletion library, we have identified genes that protect against high-O2 damage. Out of approx. 4800 mutants, 84 were identified as hyperoxia-sensitive, representing genes with diverse cellular functions, including transcription and translation, vacuole function, NADPH production, and superoxide detoxification. Superoxide plays a significant role, since the majority of hyperoxia-sensitive mutants displayed cross-sensitivity to superoxide-generating agents, and mutants with compromised SOD (superoxide dismutase) activity were particularly vulnerable to hyperoxia. By comparison, factors known to guard against H2O2 toxicity were poorly represented amongst hyperoxia-sensitive mutants. Although many cellular components are potential targets, our studies indicate that mitochondrial glutathione is particularly vulnerable to hyperoxia damage. During hyperoxia stress, mitochondrial glutathione is more susceptible to oxidation than cytosolic glutathione. Furthermore, two factors that help maintain mitochondrial GSH in the reduced form, namely the NADH kinase Pos5p and the mitochondrial glutathione reductase (Glr1p), are critical for hyperoxia resistance, whereas their cytosolic counterparts are not. Our findings are consistent with a model in which hyperoxia toxicity is manifested by superoxide-related damage and changes in the mitochondrial redox state.
A Service Architecture for Countering Distributed Denial of Service Attacks

We present AMP, a novel service architecture for countering distributed denial of service (dDos) attacks. AMP uses dynamically configured network components to perform traffic monitoring, filtering and detection of commonly known attacks. It does not require universal deployment and is complementary to other schemes for countering dDoS attacks, however with the use of collaborative policing techniques, the performance of the scheme can be improved greatly. In addition, it is economically viable, it can be offered as a service to the customers by service providers. We give a detailed design of our system which we implemented on our simulation test-bed. Performance evaluation of our system shows that using our scheme we were able to recover 83% of throughput lost during an attack.
Evidence that the Deepwater Horizon Oil Spill Caused a Change in the Nickel, Chromium, and Lead Average Seasonal Concentrations Occurring in Sea Bottom Sediment Collected from the Eastern Gulf of Mexico Continental Shelf Between the Years 2009 and 2011

Preliminary analysis indicates a change with time in nickel (Ni), chromium (Cr), and lead (Pb) concentrations in sea bottom sediment samples which were collected during the falls of 2009, 2010, and 2011 along the continental shelf of the Eastern Gulf of Mexico. These samples bracket the Deepwater Horizon Oil Spill which occurred during the spring and summer of 2010. The sea bottom samples were collected as part of the recurring NOAA small pelagics survey of the continental shelf from Texas to Florida. A Shipek grab sampler was used to retrieve 37 sediment samples from the upper 15 cm of the sea bottom for analysis from the carbonate platform off of the west coast of Florida and relict sand off of the coast of Alabama. The samples were analyzed for six trace metals, Ni, Cr, Pb, vanadium (V), thallium (Tl), and mercury (Hg). The silt/clay fraction of the sediment had the highest adsorption affinity for Ni, Pb, and Tl metals relative to V, Cr, and Hg. A comparative analysis of the trace metal concentrations indicates that there is a statistically significant (at p < 0.05 or p < 0.01) increase in Ni, Cr, and Pb concentrations in sea bottom sediment 3 months after the oil spill. One year later, however, the 2011 samples indicate that Ni, Cr, and Pb significantly decreased (at p < 0.05 or p < 0.01) in comparison to 2010. Vanadium did not statistically change from 2009 to 2011. Crude oil is known to contain V and Ni, and the V–Ni ratio (V/V+Ni) has been used as a fingerprint for the Macondo crude oil source. The V–Ni ratios for the sediment sampling years 2009, 2010, and 2011 were 0.52, 0.46, and 0.57, respectively. In this study, approximately 1 year and 3 months after the oil spill, there is evidence, such as the V–Ni ratio, that trace metal concentrations in sea bottom sediment are approaching pre-spill levels. We conclude these differences in Ni concentrations, and the V–Ni ratios are an effective means of monitoring the impact of an oil spill and the use of dispersants to alleviate the spill impact.
Research Spotlight: Using rainfall estimates to predict malaria transmission

[1] Malaria kills nearly a million people each year, mostly in rural Africa. The disease is spread by mosquitoes, which thrive in wet areas, so malaria transmission is closely linked to rainfall. Rainfall estimates could therefore be used to help predict potential malaria transmission. However, rain gauge networks are sparse in many of the rural areas that are hit hardest by malaria.
Impaired immune function in obstructive jaundice.

Sepsis is a common and occasionally lethal complication of obstructive jaundice. The reasons for this increased susceptibility to infection are unknown. This study examines lymphocyte and reticuloendothelial (RES) function in animals with obstructive jaundice. Twelve New Zealand white rabbits (3-4 kg) were studied. Lymphocyte function was evaluated in six rabbits by phytohemagglutinin (PHA), concanavalin A (Con A), and pokeweed mitogen (PWM) stimulation. In six animals, hepatic RES function was assessed by calculating the phagocytic index (PI) using the disappearance of 99Tc sulfacolloid (5 mg/kg) iv. After baseline studies, the common bile duct was divided and ligated. The above studies and serum bilirubin were repeated at 3 weeks. Obstruction was then relieved by cholecystojejunostomy (CJ) and RES studies repeated monthly x 6. Preobstructive lymphocyte function showed a stimulation index ratio (log) of 0.85 +/- 0.25 for PHA, 0.75 +/- 0.3 for Con A, and 0.71 +/- 0.25 for PWM. With biliary obstruction, the values fell to -0.23 +/- 15 (P less than 0.006), -0.31 +/- 0.12 (P less than 0.006), and -0.29 (P less than 0.006), demonstrating impaired lymphocyte function. When tested lymphocytes were mixed with control pooled rabbit serum, however, no lymphocyte impairment was noted. Baseline hepatic PI was 6.02 +/- 0.18 and fell to 3.79 +/- 0.33 with obstruction (P less than .01) and remained low at (3.20 +/- 0.14) 1 month (P less than 0.01) and (3.33 +/- 0.23) at 3 months (P less than .01), after CJ but returned to normal (8.04 +/- 0.97) at 6 months.(ABSTRACT TRUNCATED AT 250 WORDS)
Closure to "Axle Load Spectra Characterization by Mixed Distribution Modeling" by David H. Timm, S. Michelle Tisdale, and Rod E. Turochy

Closure to a discussion of an article with the aforementioned title, published in this journal (Vol. 131, No. 2, February 2005), is presented. The original authors respond to issues raised by the discusser relating to the models presented in the original paper. They reiterate that the primary objective of their study was to develop a method of load spectra characterization that used combinations of theoretical probability density functions, and then to apply the method to a number of actual load spectra to evaluate how well the model can be fit to actual data. The authors agree that the occurrence of two peaks in the probability density functions may be attributed to different truck configurations and loading characteristics. They also concur that various weigh-in-motion types and their measurement characteristics should be presented and that results of this study should be extended to other highway functional classifications and geographic regions. However, these are areas for future study.
Security and privacy produced by DHCP unique identifiers

As protection against the current privacy weaknesses of StateLess Address AutoConfiguration (SLAAC) in the Internet Protocol version 6 (IPv6), network administrators may choose to deploy the new Dynamic Host Configuration Protocol for IPv6 (DHCPv6). Similar to the Dynamic Host Configuration Protocol (DHCP) for the Internet Protocol version 4 (IPv4), DHCPv6 uses a client-server model to manage addresses in networks, providing stateful address assignment. While DHCPv6 can be configured to assign randomly distributed addresses to clients, the DHCP Unique Identifier (DUID) was designed to identify uniquely identify clients to servers and remains static to clients as they move between different subnets and networks. Since the DUID is globally unique and exposed in the clear, attackers can geotemporally track clients by sniffing DHCPv6 messages on the local network or by using unauthenticated protocol-valid queries that request systems' DUIDs or leased addresses. DUIDs can also be formed with system-specific information, further compromising the privacy and security of the host. To combat the threat of the static DUID, a dynamic DUID was implemented and analyzed for its effect on privacy and security as well as its computational overhead. The privacy implications of DHCPv6 must be addressed before large-scale IPv6 deployment.
Conserved Organization of Centromeric Chromatin in Flies and Humans

Recent studies have highlighted the importance of centromere-specific histone H3-like (CENP-A) proteins in centromere function. We show that Drosophila CID and human CENP-A appear at metaphase as a three-dimensional structure that lacks histone H3. However, blocks of CID/CENP-A and H3 nucleosomes are linearly interspersed on extended chromatin fibers, and CID is close to H3 nucleosomes in polynucleosomal preparations. When CID is depleted by RNAi, it is replaced by H3, demonstrating flexibility of centromeric chromatin organization. Finally, contrary to models proposing that H3 and CID/CENP-A nucleosomes are replicated at different times in S phase, we show that interspersed H3 and CID/CENP-A chromatin are replicated concurrently during S phase in humans and flies. We propose that the unique structural arrangement of CID/CENP-A and H3 nucleosomes presents centromeric chromatin to the poleward face of the condensing mitotic chromosome.
Marine dissolved organic carbon: Are the older values correct?

Abstract Guided by methods comparisons involving many analysts, the measurement of dissolved organic carbon (DOC) in seawater by high temperature combustion methods has been re-evaluated. Results from re-evaluation and the most recent publications using DOC data show deep water values generally similar to those reported in past decades. The similarity of the numbers have caused some oceanographers to question whether the DOC measurements now confirm earlier ideas of little or no biological reactivity below the immediate surface of the ocean. A careful assessment of the most recent analyses and re-assessment of earlier works shows distinct differences between the published conclusions from the earlier works and the interpretations made with the most modern DOC data. With accurate and precise modern analyses, it is possible to document significant differences in the DOC pool in the ocean at concentrations important to microbiological and global elemental flux studies.
μ2 Binding Directs the Cystic Fibrosis Transmembrane Conductance Regulator to the Clathrin-mediated Endocytic Pathway

Abstract The cystic fibrosis transmembrane conductance regulator (CFTR) contains a conserved tyrosine-based internalization motif, 1424YDSI, which interacts with the endocytic clathrin adaptor complex, AP-2, and is required for its efficient endocytosis. Although direct interactions between several endocytic sequences and the medium chain and endocytic clathrin adaptor complexes have been shown by protein-protein interaction assays, whether all these interactions occur in vivo or are physiologically important has not always been addressed. Here we show, using bothin vitro and in vivo assays, a physiologically relevant interaction between CFTR and the μ subunit of AP-2. Cross-linking experiments were performed using photoreactive peptides containing the YDSI motif and purified adaptor complexes. CFTR peptides cross-linked a 50-kDa subunit of purified AP-2 complexes, the apparent molecular mass of μ2. Furthermore, isolated μ2 bound to the sorting motif, YDSI, both in cross-linking experiments and glutathioneS-transferase pull-down experiments, confirming that μ2 mediates the interaction between CFTR and AP-2 complexes. Inducible overexpression of dominant-negative μ2 in HeLa cells results in AP-2 complexes that fail to interact with CFTR. Moreover, internalization of CFTR in mutant cells is greatly reduced compared with wild type HeLa cells. These results indicate that the AP-2 endocytic complex selectively interacts with the conserved tyrosine-based internalization signal in the carboxyl terminus of CFTR, YDSI. Furthermore, this interaction is mediated by the μ2 subunit of AP-2 and mutations in μ2 that block its interaction with YDSI inhibit the incorporation of CFTR into the clathrin-mediated endocytic pathway.
Nanostructured Tungsten Absorber and Emitter for Solar Thermal Photovoltaics

Using 3-D finite-difference time-domain simulations, we designed nanostructured Tungsten absorber and emitter for solar thermophotovoltaics applications. The absorber exhibits unity absorptivity over the solar bandwidth, emitter has unity emissivity at 1.1eV, corresponding to Si bandgap.
A comparison of multiple-choice and problem examinations in introductory financial accounting

Abstract This paper reports the results of research to determine if significant differences exist in a student's examination score and class ranking when based on multiple-choice or problem examinations. Students were administered examinations made up of two subtests covering the same subject matter. One subtest consisted of multiple-choice questions while the other consisted of problems. There were no significant differences in scores on multiple-choice versus problem examinations. In addition, class rankings using multiple-choice versus problem examination scores were strongly associated.
Impaired thymopoiesis in interleukin-7 receptor transgenic mice is not corrected by Bcl-2.

Murine thymocytes down-regulate IL-7 responsiveness following β-selection and reacquire sensitivity after positive selection. To assess the potential consequences of IL-7 signaling during this phase of development, transgenic IL-7 receptor alpha (IL-7Rα) mice were evaluated for IL-7 responsiveness as gauged by STAT-5 phosphorylation. Transgenic IL-7Rα expression increased the percentage of thymocytes responsive to IL-7 yet resulted in a decrease in total thymic cellularity. Aberrant thymocyte development in transgenic mice was first manifested by a reduction of DN3 thymocytes that correlated with lower Bcl-2 expression. Surprisingly, transgenic restoration of Bcl-2 expression did not correct thymic hypocellularity induced by IL-7Rα overexpression. These findings demonstrate that failure to appropriately downregulate IL-7Rα expression interferes with thymocyte development past the pro-T stage resulting in significantly lower levels of mature thymocytes.
Significance of rebounding parathyroid hormone levels during parathyroidectomy

Abstract Background Using minimally invasive parathyroidectomy (MIP), most surgeons require a 50% decline in intraoperative parathyroid hormone (IoPTH) to determine cure, but the significance of IoPTH kinetics occurring after this drop remains unknown. The aim of this study was to determine the impact of IoPTH levels that first meet criteria for cure, but then increase again, or rebound, between 10 and 15 min postexcision. Methods We conducted a retrospective review of patients undergoing initial parathyroidectomy for primary hyperparathyroidism at our institution from 2001 to 2011. Rebound IoPTH was defined as an increase in parathyroid hormone ≥5 pg/mL after achieving the 50% drop required for cure. Comparisons were evaluated with the Student t -test, chi-square test, or Fisher exact test where appropriate. Results Of the 1386 patients who met selection criteria, 86 (6.2%) patients exhibited rebound IoPTH. The mean magnitude of rebound was 13.8 ± 3.6 pg/mL. Compared with those not displaying rebound, more patients with rebound IoPTH were treated with open parathyroidectomy rather than MIP (10.8% versus 4.5%, P versus 2.2%, P = 0.03). Magnitude of rebound, however, did not correlate with recurrence. The rate of persistent disease was not different between those with and without rebound IoPTH. Rebound was a much better indicator of recurrence than patients whose final IoPTH levels were not within the normal range. Conclusions Rebound IoPTH is more common in patients who develop recurrent hyperparathyroidism. Therefore, surgeons should closely monitor patients with rebound IoPTH for disease recurrence.
Scalable MiniMD Design with Hybrid MPI and OpenSHMEM

The MPI programming model has been widely used for scientific applications. The emergence of Partitioned Global Address Space (PGAS) programming models presents an alternative approach to improve programmability. With the global data view and lightweight communication operations, PGAS has the potential to increase the performance of scientific applications at scale. However, since the PGAS models are emerging, it is unlikely that entire applications will be re-written with them. Instead, unified communication runtimes have paved the way for a new class of hybrid applications that can leverage the benefits of both MPI and PGAS models. In this paper, we re-design an existing MPI based scientific mini-application (MiniMD) with MPI and OpenSHMEM programming models. We propose two alternative designs using MPI and OpenSHMEM programming models and compare performance and scalability of those designs with the original MPI-based implementation. Our performance evaluations using MVAPICH2-X (Unified MPI+PGAS Communication Runtime over InfiniBand) show a 17% reduction in total execution time, compared to existing MPI-based design with 1,024 cores.
Methacholine bronchial challenge in children.

Abstract Methacholine sensitivity was evaluated in 166 young subjects who had normal resting spirometric values but who presented problems suggesting lower airways hyperreactivity. Fifty-eight patients (35%) did not have significant sensitivity. The diagnosis of asthma was excluded in this subgroup. Forty-one patients (25%) had mild methacholine sensitivity, 49 (30%) had moderate sensitivity, and 18 (11%) had extreme methacholine sensitivity. Many patients who reacted had chief complaints of cough, bronchitis, or other lower respiratory-tract symptoms and did not complain of wheezing. Methacholine challenge helped to clarify appropriate therapy in these individuals. One-year follow-up of these patients showed most patients to be continuing the therapeutic regimen that had been prescribed initially. Methacholine bronchoprovocation was a useful adjunct to management of this large outpatient population of children and young adults and deserves attention as a procedure relevant to patient care, not solely as an investigational test.
A molecular orbital study of exciplex structure

Abstract The extended Huckel (EH) theory has been used to study the effect of altering the geometry and properties of the components of binary and ternary amine-anthracene exciplexes. Exciplex stability is found to be a function of orbital overlap between donor and acceptor components. Stable exciplex formation imparts charge transfer character to the complex as measured by the partial charge on the donor component. The formation of ternary exciplexes generally requires a donor-donor-acceptor arrangement, and such interaction leads to increased polarity and reduced donor-acceptor overlap. Weak binary exciplexes may prefer to undergo SN2-like substitution rather than form stable ternary complexes.
High-resolution infrared spectrum and analysis of the ν9 band of ethane at 12.17 μm

Abstract The ν9 degenerate fundamental of C2H6 near 12.17 μm (822 cm−1) has been recorded at medium resolution (Δν = 0.125−0.500 cm−1) and high resolution (Δν = 0.04−0.05 cm−1) using both grating and interferometric spectrometers. The spectra have been assigned and analyzed by both standard and band contour techniques. The high-resolution spectrum showed a pronounced l-doubling in the K = 0 subband and the presence of a (2,2) type l-resonance. The assigned lines were corrected for these effects and analyzed using an energy expression through third order ( h 3 † ) with partial fourth-order ( h 4 † ) contributions. The standard deviation for the analysis of 549 of 569 assigned transitions was 6.7 × 10−3 cm−1. The ν9 band has been observed recently on Jupiter, Saturn, Titan, and Neptune by several workers. Spectra, frequency listings, and assignments have been included for use in future work on C2H6 in the atmospheres of the outer planets.
Speech Evaluation and Treatment for Patients With Cleft Palate

This compendium has been written in conjunction with a cleft lip and palate surgical mission that took place in Villahermosa, Mexico, February 4–9, 2001. Fifty children, 10 per day, received lip or...
Mexiletine, a new antiarrhythmic agent, for treatment of premature ventricular complexes

This double-blind crossover study was designed to compare the safety and efficacy or mexiletine, a new class I antiarrhythmic agent, with those of a placebo in reducing premature ventricular complexes. Twelve patients who had a median of 294 such complexes/hour were admitted to the study. Eleven completed 4 weeks of trial with mexiletine and placebo with ambulatory electrocardiographic (Holter) recordings taken at the end of each treatment period. The doses given were designed to reduce the frequency of premature ventricular complexes by 50 percent or more from the baseline value. Mexiletine significantly reduced the rate of premature ventricular complexes by comparison with placebo (-66 percent versus 3 percent, p = 0.032). In addition, mexiletine reduced the median number/hour of ventricular couplets observed. After 4 weeks of therapy, 2, 2, 1 and 6 patients, respectively, were taking 100, 200, 300 and 400 mg of mexiletine every 8 hours. Mexiletine produced no significant change in baseline values including electrocardiographic intervals, blood pressure or heart rate. The most frequently observed adverse effects were digestive difficulties (eight patients taking mexiletine, four taking placebo) and central nervous system effects (seven taking mexiletine, five taking placebo). These data show the efficacy and safety of mexiletine in the treatment of premature ventricular complexes in a majority of patients.
Area studies librarians and international book fairs: the Hong Kong Book Fair experience

In a newly established venture to support librarians who are working to build collections to better serve their East Asian user communities, the American Librarian Association (ALA) and the Hong Kong Book Fair (HKBF) provided funding for a group of ten U.S. academic and public librarians responsible for selecting Chinese language materials to attend the July 2001 HKBF, which in recent years has become one of the largest gatherings of booksellers in East Asia. This article discusses how international collection development is enhanced and professional librarian skills are honed through participation in organized programs such as the HKBF/U. S. Librarian Invitation Program.
A Comparison of Full and Single Channel Spread Spectrum Monopulse Trackers in the Presence of Jamming

The principal advantage of single channel monopulse (or pseudomonopulse) trackers versus full monopulse is the single channel monopulse system requires less hardware. The principal disadvantage is that the single channel monopulse has greater tracking jitter for a given interference level. The purposes of this paper are to compare, at the block diagram level, the hardware requirements of single channel and full monopulse systems and to quantitatively compare the RMS tracking jitter of the two systems in the presence of jamming. Band limited white noise and C. W. jamming are considered.