cssi/SciSciGPT-SciSciNet huggingface dataset:
Evaluation of 11C-Methionine PET and Anatomic MRI Associations in Diffuse Intrinsic Pontine Glioma

The role of metabolic imaging in the diagnosis, treatment, and response assessment of diffuse intrinsic pontine glioma (DIPG) is poorly defined. We investigated the uptake of 11C-methionine in pediatric patients with newly diagnosed DIPG and evaluated the associations of 11C-methionine PET metrics with conventional MRI indices and survival outcomes. Methods: Twenty-two patients with newly diagnosed DIPG were prospectively enrolled on an institutional review board–approved investigational study of 11C-methionine PET. All patients underwent baseline 11C-methionine PET/CT, and initial treatment-response scans after chemotherapy or radiation therapy were obtained for 17 patients. Typical and atypical DIPGs were assessed clinically and radiographically and defined by multidisciplinary consensus. Three-dimensional regions of interest, reviewed by consensus between a nuclear medicine physician and a radiation oncologist, were delineated after coregistration of PET and MR images. Associations of 11C-methionine uptake intensity and uniformity with survival, along with associations between 11C-methionine uptake and conventional MRI tumor indices over time, were evaluated. 11C-methionine PET voxel values within regions of interest were assessed as threshold values across proportions of the study population, and 11C-methionine uptake at baseline was assessed relative to MRI-defined tumor progression. Results:11C-methionine uptake above that of uninvolved brain tissue was observed in 18 of 22 baseline scans (82%) and 15 of 17 initial response scans (88%). 11C-methionine avidity within MRI-defined tumor was limited in extent, with 11 of 18 positive baseline 11C-methionine PET scans (61%) showing less than 25% 11C-methionine–avid tumor. The increase in total tumor volume with 11C-methionine PET was relatively limited (17.2%; interquartile range, 6.53%–38.90%), as was the extent of 11C-methionine uptake beyond the MRI-defined tumor (2.2%; interquartile range, 0.55%–10.88%). Although baseline 11C-methionine PET intensity and uniformity metrics did not correlate with survival outcomes, initial 11C-methionine avidity overlapped with recurrent tumor in 100% of cases. A clinical diagnosis of atypical DIPG was associated with borderline significantly prolonged progression-free survival (P = 0.07), yet 11C-methionine PET indices at diagnosis did not differ significantly between atypical and typical DIPGs. Conclusion: Most newly diagnosed DIPGs are successfully visualized by 11C-methionine PET. Baseline 11C-methionine uptake delineates regions at increased risk for recurrence, yet intensity and uniformity metrics did not correlate with treatment outcomes in children with DIPG in this study.
Investigation of Secondary Amine-Derived Aminal Bond Exchange toward the Development of Covalent Adaptable Networks

Secondary amine-derived aminal bonds represent an attractive class of dynamic covalent bonds that undergo rapid exchange reaction under mild conditions without the need of exogenous catalysts. The ...
Observations on Developing Reliability Information Utilization in a Manufacturing Environment with Case Study: Robotic Arm Manipulators.

Manufacturing environments face many unique challenges with regard to balancing high standards of both product quality and production efficiency. Proper diagnostic health assessment is essential for maximizing uptime and maintaining product and process quality. Information for diagnostic assessments, and reliability information in general, can come from a myriad of sources that can be processed and managed through numerous algorithms that range from simplistic to hypercomplex. One area that typifies the assortment of information sources in a modern manufacturing setting is found with the use of industrial robotics and automated manipulators. Although several monitoring methods and technologies have been previously proposed for this and other assets, adoption has been sporadic with returns on investment not always meeting expectations. Practical concerns regarding data limitations, variability of setup, and scarcity of ground truth points of validation from active industrial sites have contributed to this. This paper seeks to provide an overview of barriers and offer a feasible action plan for developing a practical condition monitoring information utilization program, matching available capabilities and assets to maximize knowledge gain. Observations are made on a real-world case study involving industrial 6 degrees of freedom (DOF) robots actively deployed in a manufacturing facility with a variety of operational tasks.
Fluoroquinolone resistant tuberculosis: A case report and literature review.

Abstract Despite the advancements made in medicine and treatment of tuberculosis over the last century, it remains a significant healthcare challenge. It remains the leading cause of death from a single infectious agent and the ninth leading cause of death worldwide. A 23-year-old male with a history of tuberculosis treated in Nepal seven years prior, presented to the emergency department with one week of hemoptysis, fever, chills, night sweats and weight loss. A CT scan of the chest showed multiple cavitary lesions at the superior segment of the left lower lobe. He had persistent massive hemoptysis and required blood transfusions. He underwent bronchial artery embolization followed by lobectomy. He was ultimately diagnosed with fluoroquinolone-resistant tuberculosis, and required a prolonged intensive care unit with transfer to a regional tuberculosis center to successfully complete treatment.
Sample size calculation for small sample single-arm trials for time-to-event data: Logrank test with normal approximation or test statistic based on exact chi-square distribution?

Abstract Background Sample size calculations are critical to the planning of a clinical trial. For single-arm trials with time-to-event endpoint, standard software provides only limited options. The most popular option is the log-rank test. A second option assuming exponential distribution is available on some online websites. Both these approaches rely on asymptotic normality for the test statistic and perform well for moderate-to-large sample sizes. Methods As many new treatments in the field of oncology are cost-prohibitive and have slow accrual rates, researchers are often faced with the restriction of conducting single arm trials with potentially small-to-moderate sample sizes. As a practical solution, therefore, we consider the option of performing the sample size calculations using an exact parametric test with the test statistic following a chi-square distribution. Analytic results of sample size calculations from the two methods with Weibull distributed survival times are briefly compared using an example of a clinical trial on cholangiocarcinoma and are verified through simulations. Results Our simulations suggest that in the case of small sample phase II studies, there can be some practical benefits in using the exact test that could affect the feasibility, timeliness, financial support, and ‘clinical novelty’ factor in conducting a study. The exact test is a good option for designing small-to-moderate sample trials when accrual and follow-up time are adequate. Conclusions Based on our simulations for small sample studies, we conclude that a statistician should assess sensitivity of his calculations obtained through different methods before recommending a sample size to their collaborators.
The risk of cytomegalovirus infection after treatment of acute rejection in renal transplant recipients.

The risk of cytomegalovirus infection (CMV) after rejection treatment is poorly understood. To investigate this, we conducted a case/control (1:2) analysis of adult renal transplant recipients between January 1, 2005 and December 31, 2015, via incidence density sampling and survival analysis. Our objective was to evaluate the association of prior acute rejection with subsequent CMV, including epidemiology and outcomes. There were 2481 eligible renal transplants within the study period and 251 distinct CMV infections. Despite the use of antiviral prophylaxis rejection was a significant risk factor for CMV on unadjusted (HR 1.73 [1.34, 2.24] P < 0.05) and adjusted analysis (HR 1.46 [1.06, 2.04] P < 0.05). When matching cases to controls patients with CMV had significantly more rejection prior to CMV diagnosis (26.7% vs 14.2%, P < 0.01). CMV was associated with a twofold increased risk of prior rejection on unadjusted (OR 1.94, 95%CI: 1.28-2.96, P < 0.01) and adjusted analysis (OR 2.16, 95% CI: 1.31-3.58, P < 0.01). Patients with rejection preceding CMV had significantly increased graft loss (HR 2.89, 95% CI: 1.65-5.09, P < 0.01) and mortality (HR 1.82, 95% CI: 1.12-4.24, P = 0.03) as compared to those CMV cases without rejection. In conclusion, rejection is a risk factor for CMV infection that appears to persist for 1 year. Preceding rejection events increased risk of graft loss and mortality in CMV patients. Given this, prolonged surveillance monitoring for CMV after rejection may be warranted. Studies are needed investigating optimal monitoring strategies.
Yours Truly? Survey on Accessibility of Our Personal Data in the Connected World

Due to the advancement of embedded sensing and wireless communication technologies, in recent times, there is a sharp rise in the number of smart personal and home (multi-user) specific devices. Sensors embedded in these devices collect significant amount of personal data including raw sensor data and derived data, such as, motion, location, heart rate, oxygen saturation, step counts. This user generated data can be helpful to understand their behavior, activity, health, and quality of life and can help healthcare providers (if shared with users' consent), to get a better insight about patients and their everyday life. The lack of control over these personal data and their flow makes the user vulnerable to external attacks and data abuse. Also, most of the devices do not allow the users to access and share their self-produced raw sensor data. In this study, we investigate the accessibility of the user generated data for a wide range of currently available devices. We also present an overview of the type of data that popular home and wearable devices collect from their users. Finally, we propose a more accessible data platform where users can store and manage their data with other stakeholders in an access-controlled manner.
Chronic Per-/Polyfluoroalkyl Substance Exposure Under Environmentally Relevant Conditions Delays Development in Northern Leopard Frog (Rana pipiens) Larvae.

Per-/polyfluoroalkyl substances (PFAS) are pervasive in aquatic systems globally and capable of causing detrimental effects on human and wildlife health. However, most studies are conducted under artificial conditions that are not representative of environmental exposures. Environmental exposures are characterized by multiple routes of exposure, low aquatic PFAS levels, and greater environmental variability than laboratory tests. Determining whether these factors influence toxicity is critical for understanding the effects of PFAS on aquatic life, including amphibians. Our goal was to assess the impact of PFAS on an amphibian under semirealistic conditions. We reared northern leopard frog (Rana pipiens) larvae in outdoor mesocosms containing sediment spiked to low, medium, and high levels (nominally 10, 100, or 1000 ppb dry wt) of perfluorooctanesulfonic acid (PFOS) or perfluorooctanoic acid (PFOA) for 30 d. Larvae in all PFOS treatments and the medium-PFOA treatment were approximately 1.5 Gosner stages less developed than control animals after 30 d. Notably, these developmental delays were observed at PFOS concentrations in the water as low as 0.06 ppb, which is considerably lower than levels associated with developmental effects in laboratory studies. Our results suggest that deriving toxicity values from laboratory studies examining aquatic exposure only may underestimate the effects of environmental PFAS exposure. Environ Toxicol Chem 2021;40:711-716. © 2020 SETAC.
Synthesis of Monodisperse Silver Chalcogenide Quantum Dots with Elevated Precursor Reactivity for the Application in Near Infrared Photodetectors

Semiconducting nanocrystals (colloidal quantum dots, QDs) have superior optical properties and solution processibility. Silver selenide quantum dots are important nanomaterials with absorption peak extending from $\sim 880$ nm to $\sim 1200$ nm. Compared to the lead-based counterparts, Ag$_{\mathbf {2}}$ Se QDs are less developed and their application is less explored. This is in part due to the difficult control of their size and size distribution, resulting in broad absorption or even featureless absorption. We employed secondary phosphine to elevate the precursor reactivity and were able to well control the nucleation and growth. After a systematic investigation on a number of synthetic parameters, high quality Ag7/$0_{\mathbf {2}}$ Se QDs have been synthesized with tunable size and narrow size distribution, exhibiting well-defined absorption peaks. The synthesis is scalable with high yield. The application of Ag$_{\mathbf {2}}$ Se QDs has been successfully demonstrated in photodetectors with photoresponse in near infrared region ($\ge 1000$ nm).
Association Between Concussion History and Factors Relating to Cognitive, Behavioral, and Emotional Health Among American High School Athletes: A Cross-sectional Analysis:

Background:The cognitive, behavioral, and emotional deficits that may be associated with sports-related concussions among adolescents are unclear.Purpose:We examined the association between reporte...
Revisiting element removal for density-based structural topology optimization with reintroduction by Heaviside projection

Abstract We present a strategy grounded in the element removal idea of Bruns and Tortorelli (2003) and aimed at reducing computational cost and circumventing potential numerical instabilities of density-based topology optimization . The design variables and the relative densities are both represented on a fixed, uniform finite element grid, and linked through filtering and Heaviside projection. The regions in the analysis domain where the relative density is below a specified threshold are removed from the forward analysis and replaced by nodal boundary conditions. This brings a progressive cut of the computational cost as the optimization proceeds and helps to mitigate numerical instabilities associated with low-density regions. Removed regions can be readily reintroduced since all the design variables remain active and are modeled in the formal sensitivity analysis. A key feature of the proposed approach is that the Heaviside projection promotes material reintroduction along the structural boundaries by amplifying the magnitude of the sensitivities inside the filter reach. Several 2D and 3D structural topology optimization examples are presented, including linear and nonlinear compliance minimization, the design of a force inverter , and frequency and buckling load maximization. The approach is shown to be effective at producing optimized designs equivalent or nearly equivalent to those obtained without the element removal, while providing remarkable computational savings.
Delayed Cranial Nerve Palsies and Chiari Type I Malformation After Epidural Anesthesia in the Setting of Childbirth

Epidural analgesia is an efficient method of controlling pain and has a wide spectrum of therapeutic and diagnostic applications. Potential complications may occur in a delayed fashion, can remain undiagnosed, and can be a source of significant morbidity. We present a 37-year-old woman presented with severe spontaneous occipital headaches, diplopia, and dizziness that occurred spontaneously six weeks after giving birth. Her primary method of pain control during labor was epidural analgesia. Her neurologic exam revealed a cranial nerve six palsy with ptosis, and her brain MRI demonstrated a Chiari I malformation which had not been previously diagnosed. CT myelography of the lumbar spine revealed extradural contrast extravasation within the interspinous soft tissue at L1-L2, which was the site of her prior epidural procedure. She underwent epidural blood patch administration, and her cranial nerve palsy resolved along with all of her other symptoms. The development of concurrent Chiari I malformation and cranial nerve palsy after epidural anesthesia is an exceptionally rare occurrence. Neurologic complications after epidural anesthesia are likely under-reported, since patients are often lost to follow-up or have subtle neurologic signs which can easily be missed. This frequently delayed presentation emphasizes the importance of patient education and the necessity of a detailed neurological exam when symptoms occur.
Ecological contexts of youth antisocial behaviors: A longitudinal perspective

The current study examined and compared the relative influence of ecological factors on youth antisocial behaviors (i.e., aggression and rule-breaking) using longitudinal data while assessing the moderating effect of youth attention-deficit/hyperactivity disorder (ADHD) diagnosis. The study used the fifth and sixth wave of data from the Fragile Families and Child Wellbeing Study (n = 2595; mean age = 9.26 at wave five) for the analysis. Multivariate models show that youth ADHD, physically and psychologically abusive parenting, peer victimization, and community cohesion were important predictors of youth antisocial behaviors. Furthermore, youth ADHD diagnosis moderated some associations between the ecological factors and antisocial behaviors, suggesting that youth with and without ADHD may respond to some ecological contexts differently regarding the concerning behaviors. The findings imply that interventions targeting youth antisocial behaviors should involve collaboration across systems and coordination across programs to tackle a multilayered ecological context, especially when youth with ADHD are involved.
Psychiatric Outcomes of Childhood Maltreatment: A Retrospective Chart Review from a Children's Psychiatric Inpatient Program.

Childhood maltreatment is linked to deleterious outcomes, whereby post-traumatic stress disorder (PTSD) has been identified as one of the most debilitating. This retrospective chart review examined whether self-reported affective measures (anxiety, depression, trauma), type of maltreatment (sexual, physical, emotional/verbal abuses), and demographics predicted a diagnosis of anxiety or PTSD among 169 children in a psychiatric inpatient hospital. Secondly, this study identified significant predictors of a PTSD diagnosis. Results indicated self-reported anxiety predicted a diagnosis of PTSD, while self-reported depression predicted PTSD only in maltreated children. Self-reported trauma predicted an anxiety diagnosis. PTSD risk variables including duration of stay, sex, self-reported anxiety, presence of sexual abuse, and presence of emotional/verbal abuse, showed sound sensitivity/specificity as predictors of risk for a PTSD diagnosis in an inpatient setting. Clinical implications are discussed.
Bringing DisCrit theory to practice in the development of an action for equity collaborative network: passion projects

Disability Critical Race Theory (Dis/Crit) was useful as a tool and a lens for the development of a collaborative network of educators, community providers, and community stakeholders including edu...
Strategy for Extensible, Evolving Terminology for the Materials Genome Initiative Efforts

Intuitive, flexible, and evolving terminology plays a significant role in capitalizing on recommended knowledge representation models for materials engineering applications. In this article, we present a proposed rules-based approach with initial examples from a growing corpus of materials terms in the National Institute of Standards and Technology (NIST) Materials Data Repository. Our method aims to establish a common, consistent, and evolving set of rules for creating or extending terminology as needed to describe materials data. The rules are intended to be simple and generalizable for users to understand and extend as well as for groups to apply to their own repositories. The rules generate terms that facilitate machine processing and decision making.
Assessment: Practical Strategies Applied to the Professions

Utilizing knowledge, skills, and attitudes as an organizational structure, this chapter reviews research into the methods of assessment during workplace training for each of the four professions (medicine, nursing, theology, and education) that are the focus of the book. Not all assessments are conducted in the “physical workplace”: frequently learners are observed and assessed in simulated, offsite situations that are meant to serve as a close approximation to conditions in the workplace. One finding was that assessment methods are often used differently in different professions; one assessment method may be used to gauge attitudes in medicine and knowledge in education. In addition, many assessment methods integrate combinations of domains, evaluating performance in both knowledge and skills, for example. The authors explore how to measure a student’s ability to translate new knowledge or attitudes into the workplace in the future and suggest practical approaches to assess learners in workplace settings.
Classification of Procaryotic Organisms and the Concept of Bacterial Speciation

Taxonomy is the science of classification of organisms. Bacterial taxonomy consists of three separate, but interrelated areas: classification, nomenclature, and identification. Classification is the arrangement of organisms into groups (taxa) on the basis of similarities or relationships. Nomenclature is the assignment of names to the taxonomic groups according to international rules (International Code of Nomenclature of Bacteria [Sneath, 1992]). Identification is the practical use of a classification scheme to determine the identity of an isolate as a member of an established taxon or as a member of a previously unidentified species.
Two Phytotoxic Anti-Tumor Proteins: Ricin and Abrin ISOLATION, CRYSTALLIZATION, AND PRELIMINARY X-RAY STUDY

Two phytotoxic proteins, ricin and abrin, have been isolated and purified, and single crystals suitable for x-ray diffraction study have been obtained. Ricin crystals belong to space group C2 with a = 177.3 A, b = 57.3 A, c = 92.2 A, and β = 105°40′. The asymmetric unit contains 1 molecule of molecular weight 50,000, as estimated from crystallographic data and measurements of the crystal water content (68% by weight) and density (1.142 g per cm3). Abrin crystals possess a probable space group P212121 with a = 74.9 A, b = 269.8 A, and c = 70.3 A, with 2 molecules of molecular weight 65,000 in the asymmetric unit.
Seasonality in One-Month Libor Derivatives

We examine the markets for one-month LIBOR futures contracts and options on those futures for a year-end price effect consistent with the previously identified year-end rate increase in one-month LIBOR. The cash market rate increase passes through to derivative prices, which allows the derivatives to properly hedge year-end interest rate risk. However, while the year-end effect appears in the derivative contract, these derivative contracts provide biased forecasts of both future interest rates and their volatility. The turn-of-the-year effect appears to contribute to the bias in the futures contract but not in the options contract. The information in the derivatives almost always subsumes simple benchmark forecasts.
Purification and kinetics of Δ1-pyrroline-5-carboxylate reductase from Drosophila melanogaster

Δ1-Pyrroline-5-carboxylate reductase has been purified 650-fold from homogenized whole, adult Drosophila melanogaster. Affinity chromatography on Blue Sepharose CL-6B yielded a 50-fold purification in a single step. The enzyme utilizes either NADPH or NADH as cofactor. It can oxidize proline and reduce NADP+ at pH 9.6. The data are consistent with the possibility that the reaction mechanism is of the Bi Bi Ping Pong type with both substrate and cofactor inhibiting at high concentrations.
Anxiety disorders among methamphetamine dependent adults: association with post-treatment functioning.

Although anxiety is one of the most prominent psychiatric complaints of methamphetamine (MA) users, little is known about the association between anxiety disorders and treatment outcomes in this population. Using data from 526 adults in the largest psychosocial clinical trial of MA users conducted to date, this study examined psychiatric, substance use, and functional outcomes of MA users with concomitant anxiety disorders 3 years after treatment. Anxiety disorders were associated with poorer alcohol and drug use outcomes, increased health service utilization, and higher levels of psychiatric symptomatology, including suicidality. Addressing anxiety symptoms and syndromes in MA users may be helpful as a means of optimizing treatment outcomes. (Am J Addict 2010;00:1–6)
Numerical studies of helical CMF generators

The COMAG-III [1] code has been used to model the dynamic behavior of a small CMF generator having a helical coil. The results have been compared with experiments which employed lightpipe diagnostics of the explosive timing together with flash radiography to time-correlate the mechanical behavior with the previously reported electrical output [2]. The code has also been used to study and compare the importance of various loss mechanisms in these generators, including ohmic heating and the flux lost by the switching action of the armature. A parameter study in which the injection current was varied is described. The possible importance of electrical breakdown is also discussed.
Zooplankton in flowing water near benthic communities encounter rapidly fluctuating velocity gradients and accelerations

The fine-scale temporal patterns of water velocities, accelerations, and velocity gradients encountered by individual zooplankters carried in ambient flow can affect their dispersal, behavior, and interaction with other organisms, but have not yet been measured in realistic flow environments. We focused on zooplankton in wavy turbulent boundary layer flow near benthic communities because such flow affects important processes, including larval settlement and prey capture by benthic zooplanktivores. Flow across fouling communities measured in the field was mimicked in a wave flume, where time-varying velocity fields over biofouled surfaces were quantified using particle image velocimetry (PIV). Trajectories of simulated zooplankters seeded into these flow fields were followed to quantify temporal patterns of velocity gradients and accelerations that individuals encountered. We found that such zooplankters are not subjected to steady velocities or velocity gradients, but rather encounter rapidly fluctuating accelerations and velocity gradients with peaks reaching several orders of magnitude above mean values and lasting fractions of a second, much shorter than the wave period. We calculated the proportion of time zooplankters spent affected (e.g., being damaged, changing behavior) by accelerations or velocity gradients and found that a small increase in mean velocity can cause a much larger increase in time affected. Animal reaction threshold and reaction time also changed the fraction of time they were affected by the flow. Using different PIV spatial resolutions showed that inter-vector spacing should be ≤0.5 Kolmogorov length (smallest eddy scale) to accurately capture velocity gradients along trajectories, but coarser resolutions (≤2–6 × Kolmogorov length) are sufficient for velocities, accelerations, and zooplankton trajectories.
Ages of physical maturation and first intercourse in black teenage males and females.

Data collected by self-administered questionnaires in 1981 in a senior and junior high school in Baltimore among 1153 respondents in grades 9-12 are the basis of a study of the ages of physical maturation and 1st intercourse in black teenage males and females. Respondents ranged in age from 13 to over 18 and averaged 16 the response rate was 98% and the quality of the answers was generally good. A positive association was found between age of menarche and age of 1st coitus; the difference between early and late maturers in the proportions initiating sexual activity at each age is greatest at 12-14 and attenuates by 17 years of age. The risk of pregnancy in the 1st 2 years following 1st intercourse is greatest for those initiating intercourse at 12-14 years. Adolescent subfecundity appears to limit risk of pregnancy to young women with early initiation of sexual activity only if intercourse begins at 11 or younger. Only among those initiating intercourse at 15 or older is there evidence of a level of contraceptive efficiency high enough to reduce the risk of pregnancy in the 1st years of sexual exposure. Young women 12-14 report the ages of their partners on average as 15-17 years. 60.7% of males reported initiating coitus before their 1st wet dream which was considered the benchmark of male sexual maturation. If puberty is considered to occur 1 year before the 1st wet dream the corresponding figure is 41.4%. 12.7% of 1st female intercourse was described as premenarcheal. Long exposure contributes disproportionately to the high risk of conceiving in this population and risks per month may be less than national data suggest. The early initiation of sexual contact creates difficulties for interventions in classroom settings and in other programs.
Renaming experience/reconstructing practice: Developing new understanding of teaching

Although teacher-thinking research is now well established, the specific mechanisms through which teachers construct new understandings of their teaching have not been closely examined. This paper presents four interrelated concepts—teachers' conceptions of practice, tensions in their practice, articulation, and local and professional language—which emerged as grounded categories from a longitudinal study of change in teachers' practice. The study focused on how a group of foreign language teachers integrated new ideas, encountered in an inservice masters' degree program, in their thinking about and activity in the classroom. The analysis traced the ways in which the teachers reconstructed their classroom practice, using professional discourse to rename their experience and thus to assign new or different meanings to their actions. The concepts, presented with illustrations from the study and accompanying analysis, have implications for research on teaching and teacher education as well as the design and execution of teacher education programs.
SIZE DISTRIBUTION AND DIURNAL CHARACTERISTICS OF PARTICLE-BOUND METALS IN SOURCE AND RECEPTOR SITES OF THE LOS ANGELES BASIN

Abstract Measurement of daily size-fractionated ambient PM10 mass, metals, inorganic ions (nitrate and sulfate) and elemental and organic carbon were conducted at source (Downey) and receptor (Riverside) sites within the Los Angeles Basin. In addition to 24-h concentration measurements, the diurnal patterns of the trace element and metal content of fine (0–2.5 μm) and coarse (2.5–10 μm) PM were studied by determining coarse and fine PM metal concentrations during four time intervals of the day. The main source of crustal metals (e.g., Al, Si, K, Ca, Fe and Ti) can be attributed to the re-suspension of dust at both source and receptor sites. All the crustals are predominantly present in supermicron particles. At Downey, potentially toxic metals (e.g., Pb, Sn, Ni, Cr, V, and Ba) are predominantly partitioned (70–85%, by mass) in the submicron particles. Pb, Sn and Ba have been traced to vehicular emissions from nearby freeways, whereas Ni and Cr have been attributed to emissions from powerplants and oil refineries upwind in Long Beach. Riverside, adjacent to Southern California deserts, exhibits coarser distributions for almost all particle-bound metals as compared to Downey. Fine PM metal concentrations in Riverside seem to be a combination of few local emissions and those transported from urban Los Angeles. The majority of metals associated with fine particles are in much lower concentrations at Riverside compared to Downey. Diurnal patterns of metals are different in coarse and fine PM modes in each location. Coarse PM metal concentration trends are governed by variations in the wind speeds in each location, whereas the diurnal trends in the fine PM metal concentrations are found to be a function both of the prevailing meteorological conditions and their upwind sources.
Baroclinic Abyssal Flow in the Presence of a Peninsula

A model of abyssal, subthermocline flow is presented for a basin in which a peninsula intrudes into the basin. The effect of the peninsula is to provide two eastern boundaries for the total basin. The latitude-independent baroclinic pressure and density anomalies on both these boundaries are determined by integral conditions, which generalize earlier work. The peninsula also produces a zonal jet between the tip of the peninsula and the western boundary. The baroclinic transport of this current is related to the blocking of westward propagating Rossby waves from the basin's eastern boundary. The baroclinic structure of this current, as well as the interior flow and the western boundary currents, are determined in terms of the distribution of deep-water sources on the perimeter of the basin, as well as by the spatial distribution of upwelling into the thermocline. For the zonal jet, boundary currents and interior the flow is strongly baroclinic. Especially in the interior, the barotropic Stommel-Arons flow is only a small residual obtained by vertically averaging the motion. The upper part of the water column responds strongly to the upwelling forcing, and the lower part of the water column is more strongly influenced by the structure and distribution of the sources. The strong recirculation, which is only weakly coupled to the structure of the sources, renders the total vertical structure of the predicted flow more complex than that of the sources.
Fluorinated NLO polymers with improved optical transparency in the near infrared

The absorption from vibrational overtones in the near infrared and specifically at 1.55 μm, is a major contribution to the optical loss of NLO polymer waveguides. In an effort to reduce this value, the specific molecular vibrations responsible, which had previously been predicted by theoretical means, were identified by solvent spectra analysis. A scheme was proposed to reduce the intrinsic absorption through synthetic modification of the polymer by replacement of appropriate aliphatic CH bonds with CF bonds. Specific bonds were chosen for replacement based on a consideration of both contribution to intrinsic absorption as well as ease of synthetic modification. The target polymer was synthesized and its absorption measured by a solution technique. A reduction in optical loss at 1.55 µ from 0.75 to 0.35 dB cm−1 was achieved. © 1995 John Wiley & Sons, Inc.
CRT-Hole Closure

The long-term stability of deep holes 1.75 inches. (4.4 cm) in diameter by 98.4 feet (30 m) created by cone penetration testing (CPT) was monitored at a site in California underlain by Holocene and Pleistocene age alluvial fan deposits. Portions of the holes remained open both below and above the 28.6-foot (8.7 m)-deep water table for approximately three years, when the experiment was terminated. Hole closure appears to be a very slow process that may take decades in the stiff soils studied here. Other experience suggests holes in softer soils may also remain open. Thus, despite their small diameter, CPT holes may remain open for years and provide paths for rapid migration of contaminants. The observations confirm the need to grout holes created by CPT soundings as well as other direct-push techniques in areas where protection of shallow ground water is important.
Measuring protein dynamics in live cells: protocols and practical considerations for fluorescence fluctuation microscopy

Quantitative analysis of protein complex stoichiometries and mobilities are critical for elucidating the mechanisms that regulate cellular pathways. Fluorescence fluctuation spectroscopy (FFS) techniques can measure protein dynamics, such as diffusion coefficients and formation of complexes, with extraordinary precision and sensitivity. Complete calibration and characterization of the microscope instrument is necessary in order to avoid artifacts during data acquisition and to capitalize on the full capabilities of FFS techniques. We provide an overview of the theory behind FFS techniques, discuss calibration procedures, provide protocols, and give practical considerations for performing FFS experiments. One important parameter recovered from FFS measurements is the relative molecular brightness that can correlate with oligomerization. Three methods for measuring molecular brightness (fluorescence correlation spectroscopy, photon-counting histogram, and number and brightness analysis) recover similar values when measuring samples under ideal conditions in vitro. However, examples are given illustrating that these different methods used for calculating molecular brightness of fluorescent molecules in cells are not always equivalent. Methods relying on spot measurements are more prone to bleaching and movement artifacts that can lead to underestimation of brightness values. We advocate for the use of multiple FFS techniques to study molecular brightnesses to overcome and compliment limitations of individual techniques.
New Diazoketone Dissolution Inhibitors For Deep U.V. Photolithography

The results of studies directed toward the design of diazoketone dissolution inhibitors for deep U.V. photolithography are described. This work has identified a useful chromophore, the 1,3-diacy1-2-diazo linkage which has the requisite spectral characteristics for use in the deep UV. Incorporation of appropriate hetero-atomes into the structure has allowed synthesis of analogs that survive common processing sequences. A detailed study of the photochemistry of these analogs led to an understanding of the importance of the stability of the ketene photoproduct on resist contrast. Imaging results are presented for a trilayer application and for excimer laser projection printing.
Structural hidden Markov models based on stochastic context-free grammars

We propose in this paper a novel paradigm that we named "structural hidden Markov model" (SHMM). It extends traditional hidden Markov models (HMMs) by considering observations as strings derived by a probabilistic context-free grammar. These observations are related in the sense they all contribute to produce a particular structure. SHMMs overcome the limit of state conditional independence of the observations in HMMs. Thus they are capable to cope with structural time series data. We have applied SHMM to data mine customers' preferences for automotive designs. A 5-fold cross-validation has shown a 9% increase of SHMM accuracy over HMM.
Bombing at the Box Office: Reviewers’ Responses to Agnosticism in Bill Maher’s Religulous

This article examines reviewers' reactions to Bill Maher's documentary film Religulous as a way of beginning a discussion of media and religious hegemony. Hegemony theory posits that dominant ideology typically trumps contesting views, even when the latter do manage to leak through the system. Given this, one might expect that film reviewers serve as a second line of defense for entrenched worldviews. Here, however, a thematic analysis of reviews from major national newspapers reveals that critics provided only slight support to traditional religious views Maher challenges in his filmic plea for agnosticism.
Presentation Wizards and You: An Instructional Design Case Study

This article presents a “messy” case study designed for intermediate and advanced students or trainees in instructional design courses. In the case study, a video production company has just hired the student as its first instructional designer to help the company position itself in the interactive video training market. The case study is presented in several scenarios. The initial scenario sets the stage, de scribing the video company and its first interactive video project. This is followed by a set of decisions the student designer must make. The subsequent scenarios add a set of complicated “realworld” constraints to the project, and are again followed by sets of decision questions for the student. The case study includes directions for the instructor, a set of enrichment questions, and a bibliography.
The influence of the ingestion of nickel pectinate upon growth of young rats

The ingestion of eighty milligrams of nickel as nickel pectinate (1256 milligrams per kilogram body weight) did not influence the growth curve of young rats over an eight week period of observation.
Parasite-Parasite Interaction of Salmonella typhimurium and Schistosoma

The parasite-parasite interaction of Salmonella and Schistosoma was studied. Salmonella typhimurium LT2 was found to associate in vitro with three human species of Schistosoma: Schistosoma mansoni, Schistosoma haematobium, and Schistosoma japonicum. Genetic mutants of S. typhimurium were allowed to interact with ligatured and unligatured worms of S. mansoni in vitro. These studies were undertaken to elucidate the mechanism(s) of the parasite-parasite interaction of Salmonella on the surface of Schistosoma. The ga/E and fla mutants showed 100% association with male schistosomes, but a reduced interaction with female worms. The rough A and pili mutants showed a significant reduction in the ability to associate with both male and female S. mansoni. Observations with the scanning electron microscope revealed that pili function in adhesion of Salmonella to the surface tegument of S. mansoni and S. haematobium. The association of Salmonella and Schistosoma may contribute to persistence of salmonella infection.
High-Resolution Conformation and Backbone Dynamics of a Soluble Aggregate of Apomyoglobin119

The structure and dynamics of soluble misfolded aggregates are poorly understood, despite their importance in protein science and disease. Water-soluble self-associated species that do not become insoluble over time are invaluable tools for high-resolution conformational studies aimed at dissecting the determinants of self-association. Here, we characterize the soluble model aggregate apomyoglobin119 (apoMb119), generated upon truncating the residues corresponding to the C-terminal helix of sperm whale apomyoglobin. The secondary structure and backbone dynamics of apoMb119, determined by multidimensional NMR at pH 6.0, reveal the presence of an N-terminal slow-tumbling core and a highly disordered flexible C-terminus displaying residual helicity and large-amplitude backbone motions on the picosecond-to-nanosecond timescale. The backbone of the apoMb119 aggregate assumes progressively increased mobility as residues get further removed from the nonpolar core and closer to the more hydrophilic C-terminal end. This structural motif establishes a useful paradigm for the topology of soluble misfolded protein aggregates in aqueous solution in the absence of stabilizing additives. The partially helical and flexible C-terminus of apoMb119's aggregate is in interesting contrast with the amyloid-related globulomers, which display dangling ends rich in β-strand. Finally, we investigate how a molecular chaperone, the substrate-binding domain of DnaK, interferes with apoMb119's aggregation.
Intraspecific nuclear DNA variation in Drosophila.

We have summarized and analyzed all available nuclear DNA sequence polymorphism studies for three species of Drosophila, D. melanogaster (24 loci), D. simulans (12 loci), and D. pseudoobscura (5 loci). Our major findings are: (1) The average nucleotide heterozygosity ranges from about 0.4% to 2% depending upon species and function of the region, i.e., coding or noncoding. (2) Compared to D. simulans and D. pseudoobscura (which are about equally variable), D. melanogaster displays a low degree of DNA polymorphism. (3) Noncoding introns and 3' and 5' flanking DNA shows less polymorphism than silent sites within coding DNA. (4) X-linked genes are less variable than autosomal genes. (5) Transition (Ts) and transversion (Tv) polymorphisms are about equally frequent in non-coding DNA and at fourfold degenerate sites in coding DNA while Ts polymorphisms outnumber Tv polymorphisms by about 2:1 in total coding DNA. The increased Ts polymorphism in coding regions is likely due to the structure of the genetic code: silent changes are more often Ts's than are replacement substitutions. (6) The proportion of replacement polymorphisms is significantly higher in D. melanogaster than in D. simulans. (7) The level of variation in coding DNA and the adjacent noncoding DNA is significantly correlated indicating regional effects, most notably recombination. (8) Surprisingly, the level of polymorphism at silent coding sites in D. melanogaster is positively correlated with degree of codon usage bias. (9) Three proposed tests of the neutral theory of DNA polymorphisms have been performed on the data: Tajima's test, the HKA test, and the McDonald-Kreitman test. About half of the loci fail to conform to the expectations of neutral theory by one of the tests. We conclude that many variables are affecting levels of DNA polymorphism in Drosophila, from properties of nucleotides to population history and, perhaps, mating structure. No simple, all encompassing explanation satisfactorily accounts for the data.
Vassopressin-induced bradycardia in fetal and adult sheep is not dependent on an increase in blood pressure

Other investigators have reported that intravenous infusion of synthetic arginine vasopressin into fetal lambs increases mean arterial pressure and decreases heart rate. To determine if the bradycardia produced by arginine vasopressin is a reflex response to the increase in blood pressure, we studied the effect of arginine vasopressin infusion on heart rate with and without blocking the increase in blood pressure. We performed 34 experiments in 12 chronically cannulated fetal lambs between 103 and 137 days' gestation. All animals had normal blood gas and pH values. Infusion of arginine vasopressin increased mean arterial pressure 10.1 ± 1.1 mm Hg and decreased heart rate 50 ± 8 bpm. Fetal heart rate decreased similarly when arginine vasopressin was infused and the hypertensive response was blocked with nitroprusside or a selective vasoconstrictor antagonist [1-(β-mercapto-β,β-cyclopentamethylene proprionic acid) 2-(0-methyl) tyrosine] arginine vasopressin. For comparison we also studied five adult nonpregnant ewes. Bradycardia was observed in the adults after infusion of arginine vasopressin alone and when the hypertensive response was blocked with the vasoconstrictor antagonist. We conclude that arginine vasopressin infusion causes a fall in heart rate independent of any increase in blood pressure in both the fetal lamb and the adult sheep.
Multimode Heat Transfer in a Near-Space Environment

A thermal circuit model has been used to examine the heat transfer characteristics of an idealized station-keeping near-space platform. Forced convection, natural convection, and thermal radiation heat transfer mechanisms have been included in the model. The contributions of forced and natural convection were incorporated using previously published correlations. Thermal radiation heat transfer was assumed to be the result of direct solar flux, planetary infrared, and planetary albedo thermal radiation contributions. Model closure was obtained by using data from the 1976 standard atmosphere model, an empirical model for wind speed and models for variable thermophysical properties. The results of the scaling analysis indicate that, as expected, natural convection may be neglected above certain altitudes. The results also show the relative importance of thermal radiation and forced convection as the dominant heat transfer mechanisms with respect to altitude. Results from parametric studies of albedo and surf...