cssi/SciSciGPT-SciSciNet huggingface dataset:
Research on the gene transfection of mdr1 mediated by adenovirus enhanced by ultrasonic microbubbles in vitro

Objective To research the transfection efficiency of mdr1 gene mediated by adenovirus enhanced by ultrasonic microbubbles in vitro. Methods Recombinant adenovirus Ad5-mdr1, which could express mdr1 gene, was cultured and mixed with ultrasonic microbubbles. Mononuclear cells in bone marrow which contained massive hematopoietic cells of the New Zealand rabbits were gathered and enriched by density gradient centrifugation, and mixed with ultrasonic microbubbles. The mixtures were cultured conventionally after ultrasound wave irradiation. The fluorescence intensity in cells was observed by fluorescence microscope, and the expression of the exogenous mdr1 gene in transferred bone marrow mononuclear cells was detected by RT-PCR, and the P-glycoprotein (expression product of mdr1 gene) in cells was detected by immunohistochemical staining. Results After the transfection, the green fluorescence had been observed in cells of adenovirus transfection group (group B), adenovirus transfection and ultrasonic irradiation group (group C), adenovirus transfection with ultrasonic microbubbles group (group D) and adenovirus transfection with ultrasonic microbubbles and ultrasonic irradiation (group E), while not in adenovirus transfection group (group A). Moreover, the fluorescence intensity in cells of group E was significantly higher than that of the other groups. The results of RT-PCR showed that the specific electrophoresis strips were observed at 157bp in 4 groups except group A, which showed that the mdr1 gene had been transferred into the genome of the cells mediated by adenovirus. The positive rate of P-gp expression in cells of group A, B, C, D and E was 0.5%, 8.5, 10%, 11.5% and 24% respectively, which were detected by immunohistochemical staining. The rate of expression of P-gp in group E was higher than that of the other groups (P<0. 05). ConclusionsThe results demonstrate that the efficiency of gene transfection and expression of mdr1 can be enhanced by adenovirus mediated ultrasonic microbubbles in vitro. Key words: Contrast media; Microbubble; Transfection
Temporal Analysis of Predictors of Pedestrian Crashes

This study investigates the relationship between pedestrian crashes and various socio-demographic, built environment, traffic exposure, and roadway characteristics across different times of day for...
The global ecology of human population density and interpreting changes in paleo-population density

Abstract Explaining variation in human population density constitutes a basic research problem in human ecology and archaeological science. To contribute to this basic research problem, we build a graphic model and conduct a global analysis of the effects of ecological variables, controlling for technological differences, on human population density. Our results indicate that human population density displays a consistent relationship with ecological variables across productive technologies. Human population density peaks in high productivity environments with moderate levels of species richness and moderate to low levels of pathogens among hunter-gatherer, subsistence agricultural, and industrial societies. Population density is lower in low productivity environments as well as environments with high productivity, high species richness and high pathogen loads. The productive technologies associated with agriculture and industrial production impact human population density more than ecological variables, and shifts toward agriculture or industrial production may weaken the effect of net primary productivity on population density. These results illustrate the nature of the relationship between population density and ecological variables, which are partly driven by climate, and the results provide a basis for hypotheses that researchers can use to analyze the potential effects of climate change on material record estimates of human paleo-population density.
FFT-based Gradient Sparsification for the Distributed Training of Deep Neural Networks

The performance and efficiency of distributed training of Deep Neural Networks (DNN) highly depend on the performance of gradient averaging among participating processes, a step bound by communication costs. There are two major approaches to reduce communication overhead: overlap communications with computations (lossless), or reduce communications (lossy). The lossless solution works well for linear neural architectures, e.g. VGG, AlexNet, but more recent networks such as ResNet and Inception limit the opportunity for such overlapping. Therefore, approaches that reduce the amount of data (lossy) become more suitable. In this paper, we present a novel, explainable lossy method that sparsifies gradients in the frequency domain, in addition to a new range-based float point representation to quantize and further compress gradients. These dynamic techniques strike a balance between compression ratio, accuracy, and computational overhead, and are optimized to maximize performance in heterogeneous environments. Unlike existing works that strive for a higher compression ratio, we stress the robustness of our methods, and provide guidance to recover accuracy from failures. To achieve this, we prove how the FFT sparsification affects the convergence and accuracy, and show that our method is guaranteed to converge using a diminishing θ in training. Reducing θ can also be used to recover accuracy from the failure. Compared to STOA lossy methods, e.g., QSGD, TernGrad, and Top-k sparsification, our approach incurs less approximation error, thereby better in both the wall-time and accuracy. On an 8 GPUs, InfiniBand interconnected cluster, our techniques effectively accelerate AlexNet training up to 2.26x to the baseline of no compression, and 1.31x to QSGD, 1.25x to Terngrad and 1.47x to Top-K sparsification.
Interferometric laser imaging for droplet sizing method for long range measurements

Abstract A recent appendix in the aircraft regulations comprises testing supercooled large droplets impinging on its surfaces. For those tests, the size and distributions of droplets need to be characterized in icing wind tunnels. In this paper, the applicability of implementation of the “Interferometric Laser Imaging for Droplet Sizing” technique inside a wind tunnel with a 3 m × 2 m open elliptical test section has been discussed. Experiments have been conducted in the laboratory for the discussion at object distance of 1.6 m and 2.29 m and droplets diameters between 360 µm and 850 µm. All the streams were previously characterized by means of the shadowgraph imaging technique. A novel approach of the Interferometric Laser Imaging for Droplet Sizing technique where droplets are not fully defocused to avoid excessive overlapping is presented. Two new image processing approaches provide in general good results as compared to previous methods.
A structured viral RNA uses molecular mimicry and conformational dynamics to coordinate multiple functions

ABSTRACT Structured RNA elements are essential for biology and are ubiquitously used by viruses to control diverse infection-critical processes. Single-stranded RNA viruses often encode multiple processes into a single RNA element to maximize the functional capacity of their compact genomes. These important and elegant ‘multifunctional’ RNAs are hypothesized to use programmed structural changes to coordinate several, sometimes opposing, functions. However, detailed molecular mechanisms of such elements are largely mysterious because of the difficulty of solving dynamic RNA structures. We exploited recent advances in cryo-EM to directly visualize the architecture and infer conformational dynamics of the brome mosaic virus tRNA-like structure (BMV TLS), a multifunctional tRNA mimic that participates in replication, translation, and encapsidation of viral RNAs and that has eluded structure determination for decades. We found that although BMV TLS is aminoacylated by cellular tyrosyl-synthetase (TyrRS), its primary conformation is incompatible with TyrRS binding. Rather, the RNA is preorganized for replication, positioning the replicase promoter and the initiation site in close proximity to each other. An alternative ‘tyrosylation-ready’ conformation requires repositioning of a conformationally dynamic structural domain, and this change must induce additional rearrangements that disrupt the ‘replication-ready’ configuration. These results demonstrate how programmed RNA dynamics can evolve to coordinate interactions with diverse cellular and viral proteins and thus organize multiple functions on a single RNA platform. Our results support the paradigm that RNA structures are inherently dynamic conformational ensembles, which enables multifunctionality. This work also highlights the emerging power of cryo-EM to dissect the dynamic conformational landscape of small discrete functional RNAs. Furthermore, we anticipate our method of rapidly mapping RNA domains within cryo-EM maps to be broadly useful.
Estimating publication bias in meta‐analyses of peer‐reviewed studies: A meta‐meta‐analysis across disciplines and journal tiers

Selective publication and reporting in individual papers compromise the scientific record, but are meta-analyses as compromised as their constituent studies? We systematically sampled 63 meta-analyses (each comprising at least 40 studies) in PLoS One, top medical journals, top psychology journals, and Metalab, an online, open-data database of developmental psychology meta-analyses. We empirically estimated publication bias in each, including only the peer-reviewed studies. Across all meta-analyses, we estimated that "statistically significant" results in the expected direction were only 1.17 times more likely to be published than "nonsignificant" results or those in the unexpected direction (95% CI: [0.93, 1.47]), with a confidence interval substantially overlapping the null. Comparable estimates were 0.83 for meta-analyses in PLoS One, 1.02 for top medical journals, 1.54 for top psychology journals, and 4.70 for Metalab. The severity of publication bias did differ across individual meta-analyses; in a small minority (10%; 95% CI: [2%, 21%]), publication bias appeared to favor "significant" results in the expected direction by more than threefold. We estimated that for 89% of meta-analyses, the amount of publication bias that would be required to attenuate the point estimate to the null exceeded the amount of publication bias estimated to be actually present in the vast majority of meta-analyses from the relevant scientific discipline (exceeding the 95th percentile of publication bias). Study-level measures ("statistical significance" with a point estimate in the expected direction and point estimate size) did not indicate more publication bias in higher-tier versus lower-tier journals, nor in the earliest studies published on a topic versus later studies. Overall, we conclude that the mere act of performing a meta-analysis with a large number of studies (at least 40) and that includes non-headline results may largely mitigate publication bias in meta-analyses, suggesting optimism about the validity of meta-analytic results.
Pointing in a different direction: a case of bilateral absence of extensor indicis.

Understanding anatomical variations, as well as, normal anatomy of the muscles and tendons of the hand is vital for successful clinical evaluation and surgery. A number of extensor muscle and tendon variations have been reported in the literature including duplication, triplication, and absence. We report a rare anatomical variation that includes bilateral absence of the extensor indicis (EI) muscles and bilateral duplication of the extensor digitorum (ED) tendon to the second digit in the forearm of an 83-year-old male cadaver during routine upper limbs dissection. In the present case, only three muscles were present in the deep compartment: extensor pollicis longus (EPL), extensor pollicis brevis (EPB), and abductor pollicis longus (APL) with bilateral absence of EI. The reported prevalence of bilateral absence of EI muscle and tendon ranges from 0.5 to 3.5% [1, 26]. The prevalence of an additional index tendon arising bilaterally from the ED muscle belly is 3.2 % of the population [1]. Extension of the index finger is governed by the actions of EI and ED. However, the four tendons of ED are linked to each other by juncturae tendinum (JT), restricting independent extension of the digits in certain postures, e.g. when the hand is fisted. With fisted hand, EI controls extension of the index finger. Clinically, EI tendons are used for tendon reconstruction procedures to restore function to the hand and thumb after trauma or tendon rupture. This report highlights the importance of anticipating anatomical variations and conducting pre-operative evaluations to confirm the presence of EI when planning tendon transfer procedures.
Effects of double-dose algebra on college persistence and degree attainment.

In 2003, Chicago Public Schools introduced double-dose algebra, requiring two periods of math—one period of algebra and one of algebra support—for incoming ninth graders with eighth-grade math scores below the national median. Using a regression discontinuity design, earlier studies showed promising results from the program: For median-skill students, double-dose algebra improved algebra test scores, pass rates, high school graduation rates, and college enrollment. This study follows the same students 12 y later. Our findings show that, for median-skill students in the 2003 cohort, double-dose significantly increased semesters of college attended and college degree attainment. These results were not replicated for the 2004 cohort. Importantly, the impact of the policy on median-skill students depended largely on how classes were organized. In 2003, the impacts on college persistence and degree attainment were large in schools that strongly adhered to the cut-score-based course assignment, but without grouping median-skill students with lower-skill peers. Few schools implemented the policy in such a way in 2004.
Driving While Black

Abstract The phenomenon of “driving while black” has ignited a heated debate: Do the police use race to target drivers? Most research on the topic compares the number of police stops and searches for a racial group to that group's distribution in the population. This approach ignores sociological theories of law, the driver's social status, the combined influence of race and sex, and whether the driver carries drugs in the car. In addition, the police are aware of being observed. To address these limitations, we surveyed undergraduates (N = 1,192) at one of the most diverse universities in the nation about their experiences with the police and their personal criminal behavior. Drawing on Black's (1976) theory of law, we examine whether a driver's race, sex, and social status influence police behavior (stop, exit, frisk, search, ticket/arrest). We also examine which drivers are most likely to have drugs in the car. The results suggest that a driver's race, sex, and social status all shape police behavior: ...
New perch for the winged helix

The human transcription factor, RFX1, is found to belong to the winged-helix family of DNA binding proteins, despite an absence of significant sequence similarity. Even more surprising is the very different mode of DNA binding as compared with previously characterized winged-helix proteins that bind to B-form DNA.
Authoring multimedia objects in collaborative ambient intelligent virtual environment

Authoring multimedia objects may be challenging when done in a collaborative ambient intelligent (AmI) environment where both the authors and the objects are geographically distributed. In our earlier work, we created a tool called LORNAV that allows an author to visualize different multimedia objects in a 3D virtual environment and to aggregate those objects and represent them in a SMIL 2.0 format. In this paper, we introduce a collaborative authoring environment that uses LORNAV's visualization and authoring services and enables multiple authors to create aggregated objects in real time based on ambient information. The overall authoring process is also enhanced with the addition of moderation and multipoint-to-multipoint audio/video conferencing services. The collaborative AmI environment is based on a JXTA peer-to-peer (P2P) network.
THE PLATELETS IN IRON-DEFICIENCY ANEMIA. I. THE RESPONSE TO ORAL AND PARENTERAL IRON.

In summary, it appears that thrombocytosis frequently accompanies the less severe anemia of iron deficiency and may be related to platelet stimulation in a manner analogous to the erythropoietin increase seen in many of the anemic states. In some of the severely anemic individuals, thrombopenia has been observed related suggestively to several factors, including severe depletion of iron as iron enzymes, a folate deficiency or a transient thrombopoietin deficit. In order to determine with any degree of certainty the etiology of the thrombocytopenia, one would have to evaluate the platelet response in a similarly afflicted group of infants treated with folic acid or simply thrombopoietin rich plasma prior to iron therapy. In regard to the intriguing difference in the platelet response to oral and parenteral iron, subsequent studies, using either extremely small amounts of parenteral iron or large amounts of oral iron, regardless of the initial platelet and hemoglobin values, might cast light on the etiology of this occurrence.
Paraspinal subfascial placement of lumbar intrathecal baclofen catheters: short-term outcomes of a novel technique

Object Techniques for the placement of intrathecal baclofen (ITB) systems have been described in detail, with special consideration given to complications from hardware placement. Risks including catheter kinking and migration, hardware erosion through the skin, and lumbar CSF leak are elevated given the often-low body mass index and poor nutritional status of this patient population. The bulk of a spinal catheter and fascial connector within the lumbar wound may increase the potential for the aforementioned risks, leading to potential risks for wound infection and breakdown. The authors' experience has led them to develop a novel method of paraspinal subfascial lumbar catheter placement to address these risks. The authors describe a novel lumbar intrathecal catheter placement technique as part of the ITB system. Methods All patients undergoing placement of an ITB system by the senior author at New York University Langone Medical Center between July 2010 and March 2011 underwent paraspinal subfascial lumb...
Asymptotic of “Rigid-Body” Motions for Nonlinear Dynamics: Physical Insight and Methodologies

The purpose of the present work is to show that an adequate basis for understanding the essentially nonlinear phenomena must also be essentially nonlinear but still simple enough to play the role of a basis. It is shown that such types of “elementary” nonlinear models can be revealed by tracking the hidden links between analytical tools of analyses and subgroups of the rigid-body motions or, in other terms, rigid Euclidean transformation. While the subgroup of rotations is linked with linear and weakly nonlinear vibrations, the translations with reflections can be viewed as a geometrical core of the strongly nonlinear dynamics associated with the so-called vibro-impact behaviors. It is shown that the corresponding analytical approach develops through non-smooth temporal substitutions generated by the impact models.
Psychological distress associated with the diagnostic phase for suspected breast cancer: systematic review.

montgomery m. & mccrone s.h. (2010) Psychological distress associated with the diagnostic phase for suspected breast cancer: systematic review. Journal of Advanced Nursing66(11), 2372–2390. Abstract Aim. This paper is a report of a review conducted to define the manifestations that characterize psychological distress during the diagnostic phase for suspected breast cancer, define the extent of psychological distress associated with the threat of potential cancer, and identify factors influencing psychological distress levels. Background. Raising the possibility that a malignancy might be present is threatening. The resulting distress is believed to influence treatment outcomes in those diagnosed with cancer and result in behavioural changes in those with benign disease. Data sources. Research papers published between January 1983 and May 2009 were identified in CINAHL, MEDLINE and PsycINFO. The search was performed using the following terms: breast cancer diagnosis, mammography, breast biopsy, breast diagnostic, anxiety, distress and uncertainty. Review methods. A systematic review was conducted of 30 studies meeting the inclusion criteria of a quantitative design with at least one standardized measure of distress and specifically addressing distress during the evaluation period. Results. It is well-documented that distress, manifested as anxiety, exists. In a small cohort of women, distress levels are heightened to worrying levels that may have long-term implications. There was strong evidence for relationships among medical history, education and trait anxiety with distress. There was no substantiation of the association between younger age and increased psychological distress that has been consistently reported with other cancers. Conclusion. It is necessary to understand the impact of factors on distress so that heightened levels can be predicted and targeted by interventions initiated at the first mention of the possibility of the presence of malignancy.
Problem-Posing: A Teaching Strategy for Improving the Decision-Making Process

Abstract Problem-posing rather than problem-solving is proposed as an effective health education model for addressing the health decision-making of adolescents. The model suggests that participation of people in dialogue efforts and group action, directed toward community, peer groups, and individual concerns, enhance scontrol and beliefs in people's ability to change their own lives. The dialogue approach, which comes from the work of Brazilian educator Paulo Freire, enables students to identify their problesms, critically assess social and historical roots of problems, and envision a healthier future for themselves and their communities. Problem-posing broadens youth's individual perspectives on social issues and, therefore, improves the decision-making process of individuals for action to resolve their own issues.
Lack of susceptibility of soil-inhabiting Platyprepia virginalis caterpillars, a native arctiid, to entomopathogenic nematodes in nature

Entomopathogenic nematodes (EPNs) can kill and regulate populations of soil-inhabiting insects, but studies evaluating these interactions in native ecosystems are rare. The objective of this study was to examine the effects of EPNs on a non-agricultural caterpillar, Platyprepia virginalis (Boisduval) (Lepidoptera: Arctiidae), under natural conditions. Platyprepia virginalis caterpillars live in litter on the soil surface feeding beneath bush lupine during summer, autumn, and winter. Initial laboratory assays revealed that the caterpillars were vulnerable to at least two species of EPNs with which they co-occur in the coastal prairie in northern California (USA). In contrast to laboratory assays, caterpillars survived exposure to prairie soil containing EPNs under natural conditions in field assays. To better understand the divergence between laboratory and field results for this native caterpillar, we used sentinel insects [Galleria mellonella L. (Lepidoptera: Pyralidae)] to identify particular locations where EPNs were present in the field. Platyprepia virginalis caterpillars were caged at these sites but again showed no evidence of susceptibility to EPNs. Platyprepia virginalis caterpillars reduce their exposure to EPNs by spending their time in and above the litter rather than contacting the soil when given the choice in nature. We conclude that P. virginalis is unlikely to serve as a reservoir for EPNs and that nematodes are unlikely to be important mortality factors for P. virginalis in this natural system.
Properties of D-xylose isomerase from Streptomyces albus.

A partially purified D-xylose isomerase has been isolated from cells of Streptomyces albus NRRL 5778 and some of its properties have been determined. D-Glucose, D-xylose, D-ribose, L-arabinose, and L-rhamnose served as substrates for the enzyme with respective Km values of 86, 93, 350, 153, and 312 mM and Vmax values measuring 1.23, 2.9, 2.63, 0.153, and 0.048 μmol/min per mg of protein. The hexose D-allose was also isomerized. The enzyme was strongly activated by 1.0 mM Mg2+ but only partially activated by 1.0 mM Co2+. The respective Km values for Mg2+ and Co2+ were 0.3 and 0.003 mM. Mg2+ and Co2+ appear to have separate binding sites on the isomerase. These cations also protect the enzyme from thermal denaturation and from D-sorbitol inhibition. The optimum temperature for ketose formation was 70 to 80 C at pH values ranging from 7 to 9. D-Sorbitol acts as a competitive inhibitor with a Ki of 5.5 mM against D-glucose, D-xylose, and D-ribose. Induction experiments, Mg2+ activation, and D-sorbitol D-sorbitol inhibition indicated that a single enzyme (D-xylose isomerase) was responsible for the isomerization of the pentoses, methyl pentose, and glucose.
Metabolism of lysine and leucine derived from storage protein during the germination of maize.

Abstract The metabolism of [U- 14 C]leucine or [U- 14 C]lysine during the germination of maize was studied using seed in which the storage protein was labelled. The labelled amino acids were injected below the ear of maize plants during seed development. The storage protein contained a large excess of leucine but insufficient lysine for synthesis of new protein in the developing axis. The axis preferentially utilized leucine and lysine (and possibly proline) derived from storage protein for synthesis of new protein. Excess leucine was respired as CO 2 with little conversion to other amino acids. The lysine deficit was met by synthesis of new unlabelled carbon skeletons.
Effect of phase noise in Dense Wavelength Division Multiplexing (DWDM) networks

In this paper, the phase stability of 50 km externally modulated 256-QAM DWDM fiber optic link is evaluated. The analysis of RF phase noise in the fiber optic link is the main objective of this work. RF phase noise is mainly investigated with preamplifier (EDFA) configuration at 1550 nm wavelength. BER curves, constellation diagrams and Eye diagrams are the three main performance criteria considered through this paper.
On the power of combinatorial and spectral invariants

We extend the traditional spectral invariants (spectrum and angles) by a stronger polynomial time computable graph invariant based on the angles between projections of standard basis vectors into the eigenspaces (in addition to the usual angles between standard basis vectors and eigenspaces). The exact power of the new invariant is still an open problem. We also define combinatorial invariants based on standard graph isomorphism heuristics and compare their strengths with the spectral invariants. In particular, we show that a simple edge coloring invariant is at least as powerful as all these spectral invariants. (C) 2009 Elsevier Inc. All rights reserved.
Cerebrovascular Events in 21 105 Patients With Atrial Fibrillation Randomized to Edoxaban Versus Warfarin: Effective Anticoagulation With Factor Xa Next Generation in Atrial Fibrillation-Thrombolysis in Myocardial Infarction 48

Background and Purpose—The once-daily oral factor Xa inhibitor, edoxaban, is as effective as warfarin in preventing stroke and systemic embolism while decreasing bleeding in a phase III trial of patients with atrial fibrillation at moderate–high stroke risk. Limited data regarding cerebrovascular events with edoxaban were reported previously. Methods—We analyzed the subtypes of cerebrovascular events in 21 105 patients participating in Effective Anticoagulation with Factor Xa Next Generation in Atrial Fibrillation-Thrombolysis in Myocardial Infarction 48 (ENGAGE AF-TIMI 48) comparing outcomes among patients randomized to warfarin versus 2 edoxaban regimens (high dose, low dose). The primary end point for this prespecified analysis of cerebrovascular events was all stroke (ischemic plus hemorrhagic), defined as an abrupt onset of focal neurological deficit because of infarction or bleeding with symptoms lasting ≥24 hours or fatal in <24 hours. Independent stroke neurologists unaware of treatment adjudicate...
Multiple Testing of Composite Null Hypotheses in Heteroscedastic Models

In large-scale studies, the true effect sizes often range continuously from zero to small to large, and are observed with heteroscedastic errors. In practical situations where the failure to reject small deviations from the null is inconsequential, specifying an indifference region (or forming composite null hypotheses) can greatly reduce the number of unimportant discoveries in multiple testing. The heteroscedasticity issue poses new challenges for multiple testing with composite nulls. In particular, the conventional framework in multiple testing, which involves rescaling or standardization, is likely to distort the scientific question. We propose the concept of a composite null distribution for heteroscedastic models and develop an optimal testing procedure that minimizes the false nondiscovery rate, subject to a constraint on the false discovery rate. The proposed approach is different from conventional methods in that the effect size, statistical significance, and multiplicity issues are addressed in...
Dialectical disorientation in Vietnam War films: Subversion of the mythology of war

“Dialectical disorientation” is a rhetorical form that creates uncertainty and ambiguity through confrontation between two competitive but complementary orientations. This essay examines its dynamics in four films addressing the war in Vietnam: The Deer Hunter, Apocalypse Now, Platoon, and Full Metal Jacket. We argue that the works subvert traditional American war mythology. The films present the war as destructive rather than regenerative and purposeless rather than meaningful. This divisive scene creates a context in which principles governing behavior in war—militarism and moralism—become inoperative. The essay first details the development of disorientation in the films and then examines the rhetorical and social implications of the analysis.
Compositional Difference between Abyssal Tholeiites from North and South of the Azores on the Mid-Atlantic Ridge

WE have recently found that the abyssal tholeiites from the Mid-Atlantic Ridge north of the Azores differ in chemical composition range from those of the Ridge south of the Azores. This is clearly demonstrated in Fig. 1, in which the CaO and Na2O contents and CaO/Na2O ratios of abyssal tholeiites are plotted against the latitude of their dredge positions. The Azores are at about 39° N. The northern limit represented in this diagram is the Iceland coast (about 63° N).
P68 RNA helicase unwinds the human let-7 microRNA precursor duplex and is required for let-7-directed silencing of gene expression.

MicroRNAs are short, single-stranded RNAs that arise from a transient precursor duplex. We have identified a novel activity in HeLa cell extracts that can unwind the let-7 microRNA duplex. Using partially purified material, we have shown that microRNA helicase activity requires ATP and has a native molecular mass of ∼68 kDa. Affinity purification of the unwinding activity revealed co-purification of P68 RNA helicase. Importantly, recombinant P68 RNA helicase was sufficient to unwind the let-7 duplex. Moreover, like its native homolog, P68 RNA helicase did not unwind an analogous small interfering RNA duplex. We further showed that knockdown of P68 inhibited let-7 microRNA function. From our data, we conclude that P68 RNA helicase is an essential component of the let-7 microRNA pathway, and in conjunction with other factors, it may play a role in the loading of let-7 microRNA into the silencing complex.
Digital demodulation of an interferometer for the characterization of vibrating microstructures

The rapid expansion of the microelectromechanical systems (MEMS) industry and the increasing number of applications in communications, displays, and sensing has led to an increasing demand for robust characterization techniques capable of in situ characterization of MEMS structures. Interferometry is well suited to such characterization due to its wide measurement dynamic range, its fine resolution, and its non-invasive qualities. We have constructed a fiber optic interferometer for the in situ characterization of MEMS structures. We report the development and implementation of a real-time digital signal processing (DSP) algorithm to demodulate the interferometer. We have developed a computationally efficient algorithm for both stabilization of the interferometer at quadrature and determination of the target’s vibration amplitude. We have verified our demodulation scheme using a piezoelectric transducer driven mirror as the target. Our current system will measure vibration amplitudes down to 10 nm. Both theoretical and experimental results are presented.
Analytical modeling of damping at micromechanical level in polymer composites reinforced with coated fibers

Theoretical models using theory of elasticity, finite-element, and mechanics-of-materials formulations for characterizing the damping loss factor of composites with coated fiber reinforcement are described. The theoretical models are validated through comparison with experimental damping results conducted on composites having coated fibers as reinforcement. Explicit micromechanics equations are presented in order to define the damping and stiffness of unidirectional coated fiber composites under longitudinal normal (LN), transverse normal (TN), transverse shear (TS) and longitudinal shear (LS) loading conditions. Since shear deformation is essential for viscoelastic damping in polymers, and large shear strains are generated near the fiber/matrix interface in composites, it is shown that the use of a viscoelastic polymer coating on the fibers is an effective way of improving damping in such composites. A strain-energy approach was implemented with both a closed-form theory-of-elasticity solution and finite-element numerical simulations in order to carry out the analysis.
Clonality in myeloproliferative disorders: analysis by means of the polymerase chain reaction.

Abstract The myeloproliferative syndromes are acquired disorders of hematopoiesis that provide insights into the transition from somatic cell mutation to neoplasia. The clonal origin of specific blood cells can be assessed in patients with X chromosome-linked polymorphisms, taking advantage of random inactivation of the X chromosome. We have adapted the PCR for determination of clonality on as few as 100 cells, including individual colonies grown in culture. Amplifying a polymorphic portion of the X chromosome-linked phosphoglycerate kinase (PGK) gene after selective digestion of the active X chromosome with a methylation-sensitive restriction enzyme gave results fully concordant with standard Southern blotting of DNA samples from normal (polyclonal) polymorphonuclear cells (PMN) as well as clonal PMN from patients with myelodysplastic syndrome and polycythemia vera (PCV). We have used this technique to demonstrate heterogeneity of lineage involvement in patients with PCV. The same clinical phenotype may arise from clonal proliferation of different hematopoietic progenitors.
Control of muscle insulin receptors by the motor nerve.

I125 insulin binding and the uptake of oxygen and 2-deoxyglucose are increased in skeletal muscle after denervation, suggesting an increase in insulin receptors (IR). Sustained increases in the number of affinity of IR molecules may account for some properties of denervated muscle fibres.
FTIR spectra of matrix isolated complexes between sulfur compounds

Abstract The matrix isolation technique has been coupled with Fourier transform infrared spectroscopy to isolate and to characterize the complex between methanethiol and dimethyl sulfide as well as the complexes between sulfur dioxide and a series of dialkyl sulfides including (CH 3 ) 2 S, (C 2 H 5 ) 2 S and CH 3 SC 2 H 5 . The 1:1 CH 3 SH-S(CH 3 ) 2 complex was isolated and characterized by the i.r. frequency shifts of the sub-molecule methanethiol. In each of the SO 2 /sulfide systems, evidence was obtained for the formation of a 1:1 complex through the disulfide interaction. Vibrational assignments were also suggested for the 1:2, sulfide-(SO 2 ) 2 , complexes.
The propagation characteristics of signal lines embedded in a multilayered structure in the presence of a periodically perforated ground plane

The propagation characteristics of waves along a periodic array of parallel signal lines in a multilayered structure in the presence of a periodically perforated ground plane are studied. To analyze this structure, the spectral-domain immittance approach is used to derive the Green's function. The surface current density on the conductors is expressed in terms of a set of rooftop subdomain basis functions. The boundary condition is then enforced in conjunction with the Galerkin procedure, leading to an eigenvalue problem for the propagation constant which is solved by the Newton-Raphson algorithm. The dispersion characteristics of these signal lines are studied for both balanced and unbalanced excitations with the relative permittivities of the various layers as parameters. Numerical results are presented and compared with available data. Extension of the present method to treat conductors with finite sheet resistances is also discussed. >
Lanthanide Series And Transition Metal Solid-State Lasers Meeting New Objectives With Solid-State Lasers

Ater the initial introduction of the first solid-state laser, there was a flurry of research directed toward the discovery of new lasers. Activity during this period of time produced the Cr:Al2O3 laser and the Nd:YAG laser. For a relatively long time after this, research directed toward the discovery of new solid-state lasers appeared to subside. Over the past several years, this trend seemed to reverse itself. Cr:BeAl2O4 was one of the first of the new lasers to be introduced. Rather than concentrate either on this laser or on Nd-based lasers, this talk will be directed toward other new solid-state lasers. New lasers, or rediscovery of old lasers, has concentrated on two groups of elements, the lanthanide series elements and the transition metal elements. A substantial difference exists between the solid-state lasers depending on the group of elements of which the active atom is a member. Differences and similarities will be highlighted as the methods used in solid-state laser engineering to meet new objectives are explored.
Seasonality in asset returns: Evidence from the gold market

In this paper we test monthly mean daily returns to gold over the period January 1975 to December 1984 against three definitions of seasonality. Weak evidence exists for seasonality under the second of the three definitions. However, this is not prima facie evidence of market inefficiency, as the pattern is consistent with seasonality in Eurodollar interest rates reported by other authors. Differences in the time pattern of returns between on- and off-shore rates raises further questions.
Thalidomide-Induced Toxic Epidermal Necrolysis

Toxic epidermal necrolysis (TEN) is a severe dermatologic disorder associated with mortality of up to 30%. Withdrawal of the causative agent is crucial in its management. Although thalidomide-induced dermatologic disorders rarely were reported before thalidomide was administered to patients positive for the human immunodeficiency virus, hypersensitivity reactions including rash are the agent's major dose-limiting toxicities in this population. As it is prescribed for other immunosuppressed patients, such as those with malignancies, the frequency of dermatologic reactions (including TEN) may increase. A 62-year-old woman developed TEN after approximately 5 weeks of thalidomide therapy for the treatment of a glioblastoma.
Acquired resistance to O6-benzylguanine plus chloroethylnitrosoureas in human breast cancer.

Purpose: O6-benzylguanine (BG) is a pseudosubstrate inactivator of the DNA repair protein O6- alkylguanine-DNA alkyltransferase (AGT) that has entered clinical trials as a potentiatier of the antitumor effect of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). This study was designed to evaluate potential mechanisms of BG + BCNU resistance in breast cancer cells. Methods: We treated MCF-7 breast cancer cells three times with cytotoxic concentrations of BG + BCNU to isolate a population of MCF-7 cells possessing BG + BCNU resistance (BBR). We measured drug resistance, AGT activity, cross-resistance to other agents and sensitivity of AGT to BG inactivation. Results: When compared with the parent line, MCF-7BBR cells were no longer sensitized to BCNU by BG, resulting in three-fold resistance to BG + BCNU and fourfold resistance to BG + 1-(2-chloroethyl)-1-nitrosourea (CNU). In contrast, MCF-7 and MCF-7BBR cells had similar sensitivity to BCNU, CNU, temozolomide (each in the absence of BG), cisplatin, and UV light. Acquired resistance to BG + chloroethylnitrosoureas (CENU) in MCF-7BBR cells was not accompanied by an increase in AGT or altered kinetics of BG inactivation of AGT. While glutathione-S transferase activity was increased modestly, its contribution to resistance in this setting remains unclear. Conclusions: This is the first report of acquired BG + CENU resistance in human tumor cells and the results indicate that selective pressure with BG + CENUs may result in nonresponsiveness to BG by one or more complex mechanisms. These results predict the development of acquired resistance to BG + BCNU in clinical trials.
The relationship between the learning organization concept and firms' financial performance: An empirical assessment

The concept of the learning organization has received considerable attention in the scholarly literature because superior learning processes have been heralded as a source of competitive advantage. Organizations that embrace strategies consistent with the learning organization are thought to achieve improved performance. Yet few empirical studies have examined the relationship between the learning organization concept and firms' financial performance. To assess this association, the authors obtained managerial responses to the Watkins and Marsick Dimensions of the Learning Organization Questionnaire (DLOQ©) instrument along with both perceptual and objective measures of firms' financial performance. Results suggest a positive association between the learning organization concept and firms' financial performance. The article discusses implications for research and practice.
Effects of solvents on the tautomerization of N,N-dimethylglycine

The effects that solvents have on the tautomerization of N,N-dimethylglycine are analyzed and the solvent's dipolarity/polarizability and acidic properties appear to play important roles in the solvation of the zwitterionic tautomer. Owing to the existence of a stable intramolecular hydrogen-bonded conformer of the zwitterion, in which the acidic hydrogen of the ion is hydrogen bonded to the carboxylate functionality, solvation of the zwitterion by basic solvents is not very important. © 1997 John Wiley & Sons, Ltd.
Direct measurement of single-molecule diffusion and photodecomposition in free solution

Continuous monitoring of submillisecond free-solution dynamics of individual rhodamine-6G molecules and 30-base single-stranded DNA tagged with rhodamine was achieved. Fluorescence images were recorded from the same set of isolated molecules excited either through the evanescent field at the quartz-liquid interface or as a thin layer of solution defined by micron-sized wires, giving diffraction-limited resolution of interconnected attoliter volume elements. The single-molecule diffusion coefficients were smaller and the unimolecular photodecomposition lifetimes were longer for the dye-DNA covalent complex as compared with those of the dye molecule itself. Unlike bulk studies, stochastic behavior was found for individual molecules of each type, and smaller diffusion coefficients were observed.
Ongoing DNA synthesis continues in young human diploid cells (HDC) fused to senescent HDC, but entry into S phase is inhibited

Abstract Previous experiments have shown that when young human diploid cells (HDC) were fused to senescent HDC, neither nucleus synthesized DNA. This paper demonstrates that when young HDC are in S phase at the time of fusion to senescent HDC, they do make DNA in heterodikaryons; therefore, ongoing DNA synthesis is not inhibited by senescent cells. On the other hand, entry into S phase is inhibited: young HDC nuclei in G1 phase do not make DNA in heterodikaryons with senescent HDC.
Global pressure relaxation procedure for compressible turbulent strong interaction flows

Abstract Numerical turbulent solutions of the compressible RNS equations are obtained by means of the global pressure relaxation procedure. The ellipticity of the RNS equations in this computational approach is conveniently but appropriately represented by the streamwise pressure gradient term in a multi-pass boundary-layer-like marching technique. The numerical formulation includes the full effect of the elliptic pressure interaction and, therefore, allows computation of strong viscous—inviscid interacting flows. The flow regimes considered contain many of the characteristic features of complex fluid flows, e.g. recirculation, embedded shock waves and mixing shear layers. Simple algebraic turbulent closure models are employed. Results are presented for axisymmetric geometries. Comparison is made with available experimental and numerical data.
Synthetic image generation of shallow water using an iterative layered radiative transfer model with realistic water surface waves

Modeled hyperspectral reflectance signatures just above the water surface are obtained from an analytical radiative transport model applicable to shallow water types. Light transport within the water body is simulated using a fast, accurate radiative transfer model that calculates the light distribution in any layered media. A realistic water surface is synthesized using empirically-based statistical models of ocean surface waves. Images are displayed as 24 bit RGB images of the water surface using selected channels. The selected channels are centered at 480, 520 and 650 nm. Hyperspectral image cubes with two spatial and a third spectral dimension are shown to allow the detection of any optically unresolved features in the two-dimensional RGB image.