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Type 2 (T2) inflammation plays a key role in the pathogenesis of asthma. IL-4, IL-5, and IL-13, along with other inflammatory mediators, lead to increased cellular eosinophilic inflammation. It is likely that around half of all patients with asthma have evidence of T2-high inflammation. Sputum and blood eosinophils, exhaled nitric oxide, blood IgE levels, and airway gene expression markers are frequently used biomarkers of T2-high asthma. Individuals with T2-high asthma tend to have several features of increased asthma severity, including reduced lung function and increased rates of asthma exacerbations, and T2-high patients demonstrate distinct pathologic features including increased airway remodeling and alterations in airway mucus production. Several monoclonal antibodies are now available to treat individuals with T2-high asthma and these medications significantly reduce asthma exacerbation rates.

Glioblastoma multiforme (GBM) has few clinically approved therapeutic regimens. One of these therapeutic options includes placing biodegradable wafers releasing BCNU (Gliadel®) into the tumor bed at the time of surgical removal of the tumor. Due to the significant benefit this polymer technology has had clinically, we have prepared wafers releasing Temozolomide (TMZ), an anticancer drug used systemically for treating GBM. TMZ delivered via polymer wafer could be used as a complementary treatment with or as an alternative to Gliadel®. TMZ is an alkylating agent which is water soluble. To remain comparable with the preclinical studies that led to Gliadel® the same size of wafers were formulated with TMZ. Wafers were loaded with 50% w/w TMZ in poly(lactic acid-glycolic acid) (PLGA) and showed reliable release of high dose TMZ for a period of 4 weeks. To achieve this 30-day release of the highly water soluble drug, we developed an encapsulation method, where the drug powder was first coated with the polymer to form core-shell particles in which the coating shell served as a rate controlling membrane for the drug particles. Wafers were also made with a co-loading of TMZ and BCNU. All wafers were tested in vivo by treating an intracranial 9 L gliosarcoma model in F344 rats. Rats that were either untreated or treated with blank wafer died within 11 days while the median survival for rats treated with systemic TMZ was 18 days. The group that received the BCNU alone wafer had a median survival of 15 days, the group that received the TMZ wafer alone had a median survival of 19 days, and the group treated with the BCNU-TMZ wafer had a median survival of 28 days with 25% of the animals living long term (p .0038 vs. Control; p .001 vs. Blank Polymer). These findings demonstrate the potential of this newly designed wafer for treating GBM. Moreover, this concept, can pave the way for other drug combinations that may improve the clinical application of numerous agents to treat solid tumors.

Background We designed an Internet-Based Monitoring Systems (IBS) survey to facilitate monitoring of asthma symptoms and asthma exacerbations in the Severe Asthma Research Program (SARP). Our objective was to evaluate compliance with the IBS survey tool and to explore how data from an IBS tool can inform understanding of asthma phenotypes. Methods We invited adult subjects in the SARP III cohort (N = 528) to complete a monthly IBS asthma control survey. We compared the characteristics of subjects who did and those who did not participate in the IBS survey tool. Among subjects who participated in the IBS (IBS+), we identified participants with low, medium, and high Asthma Control Test (ACT) score variability, and we explored asthma morbidity in these three participant subgroups. Results Two hundred fifty-nine subjects participated in the IBS (IBS+) survey. Compared with subjects who did not engage with the IBS (IBS–) survey, IBS+ subjects were older and more likely to be white, college educated, and have an annual household income > $25,000, and have controlled asthma. Among IBS+ participants, the subgroup with the highest ACT score variability was more likely to have severe asthma, with a lower ACT score at baseline and increased asthma-related health-care use (often precipitated by cold and flulike illnesses). Participants with high ACT variability were also characterized by metabolic dysfunction, as evidenced by obesity and hypertension. Conclusions Active participation with an Internet-based symptom survey tool in patients with severe asthma is influenced by race, socioeconomic status, and asthma control. Among survey participants, a group with highly variable (labile) asthma control is identifiable as a specific subgroup with unmet treatment needs. The association of asthma lability, increased susceptibility to adverse asthma effects of cold and flulike illnesses, and metabolic dysfunction provides clues for potentially effective intervention strategies.

Background: Informal providers (IP) have a large presence in India’s health workforce; they are usually first contact primary care providers for rural populations. Patients with COVID-19 symptoms will likely first see an IP. This study aims to understand COVID-19 knowledge and management practices of IPs and trained practitioners of Indian systems of medicine (AYUSH), and medical doctors (MBBS) in the state of Bihar, India. Methods: In a 2019 household survey we identified primary care providers who had served patients in the last month. Providers were contacted via telephone in July 2020 when Bihar was experiencing a rapid increase in COVID cases. Using structured questionnaires we interviewed 452 IPs, 57 AYUSH, and 38 MBBS doctors (including 23 government doctors) from 224 villages across 34 of 38 districts in Bihar. Findings: Most providers experienced a fall in patient visits during the pandemic. Most IPs and qualified private providers had no engagement with government agencies; their principal source of COVID-19 information was television and newspapers. IP knowledge levels of COVID-19 and its prevention was comparable with qualified providers. There was low stated compliance among IPs (16%) and qualified providers (15% of MBBS doctors, and 12% of AYUSH practitioners) with all WHO recommended practices for suspect COVID-19 cases. Interpretation: Government action to improve IP and other primary care provider COVID-19 knowledge and case management will strengthen efforts to control the pandemic, particularly in rural areas. Because IPs are embedded within communities, they can make important contributions to contact tracing efforts and public health messaging. Funding Statement: Bill and Melinda Gates Foundation, India. Declaration of Interests: None declared for KDR, JK, MKP, and NK. PN is employee of the funding agency. Ethics Approval Statement: Ethical approval was granted by the Indian Institutional Review Board in India (Reference number: 1007/IRB/20-21) as well as Johns Hopkins University Institutional Review Board. The purpose of the study was explained and oral informed consent was obtained from each respondent.

Osteocalcin (OC), a protein synthesized by osteoblasts, is a marker of bone turnover with undercarboxylated OC (ucOC) being involved in glucose homeostasis. Although laparoscopic Roux-en-Y gastric bypass (LRYGB)-induced weight loss likely alters bone turnover, data on markers of bone turnover remain less clear. The aim of this study was to examine the effect of surgically induced weight loss on OC and ucOC.A total of 32 individuals with a body mass index 50.2±10.2 kg/m(2) underwent LRYGB. Osteocalcin, ucOC, other blood analytes (e.g., vitamin D, leptin, total and high-molecular-weight adiponectin), and homeostasis model assessment for insulin resistance were measured before and after weight loss. The effect of an acute nutrient load on OC parameters after a mixed meal tolerance test also was assessed.Six months after surgery, there was an increase in OC (17.8±7.4 [mean±SD] [baseline] versus 31.5±9.8 ng/mL [follow-up]; P.001) and ucOC (7.3±6.2 versus 18.5±8.9 ng/mL; P.001). Although adiponectin increased, only the magnitude of change in OC and leptin was correlated (r =-.43; P = .017). After weight loss, an acute nutrient load reduced OC (31.5±9.8 [0-hour] versus 29.6±8.2 [2-hour] ng/mL; P = .024), whereas ucOC was higher (18.8±9.3 [0-hour] versus 21.1±8.6 [2-hour] ng/mL; P.001).Surgically induced weight loss was associated with increases in OC and ucOC. Underlying mechanisms are unclear, but change in OC may be related to change in leptin. After a nutrient load, the increase in ucOC suggests a potential role as a short-term compensatory regulator of glucose homeostasis.

We consider the efficient deterministic solution of elliptic boundary value problems with random diffusion matrix. Assuming random perturbations with known k moments, we derive, to leading order in the random perturbation?s amplitude, deterministic equations for k moments of the random solution. The solution?s k-th moment satisfies a k-fold tensor product boundary value problem on the k-fold product domain which can efficiently be discretized in sparse tensor product spaces. By defining the complement spaces via Galerkin projections, the related system of linear equations decouples and can be solved by standard multilevel finite element solvers. Numerical results for k = 2 are presented to validate and quantify our theoretical findings.

We compare fast black-box boundary element methods on parametric surfaces in $\mathbb{R}^3$. These are the adaptive cross approximation, the multipole method based on interpolation, and the wavelet Galerkin scheme. The surface representation by a piecewise smooth parameterization is in contrast to the common approximation of surfaces by panels. Nonetheless, parametric surface representations are easily accessible from Computer Aided Design (CAD) and are recently topic of the studies in isogeometric analysis. Especially, we can apply two-dimensional interpolation in the multipole method. A main feature of this approach is that the cluster bases and the respective moment matrices are independent of the geometry. This results in a superior compression of the far field compared to other cluster methods.

Obesity is associated with autonomic imbalance. With respect to cardiovascular autonomic dysfunction, this is characterized by reduced heart rate variability (HRV). Our objective was to determine the effect of surgically induced weight loss on cardiovascular autonomic nerve fiber function in subjects with severe obesity and examine whether an association with reduced insulin resistance exists. The setting was a hospital and private practice in the United States.A total of 32 morbidly obese patients (body mass index 51 ± 11 kg/m(2)) underwent laparoscopic Roux-en-Y gastric bypass. Measures of HRV (e.g., power spectral analysis, RR variation during deep breathing) were used to evaluate autonomic function before and 6 months after surgery. The homeostasis model assessment of insulin resistance index (HOMA-IR) was used to assess insulin resistance.At 6 months after bariatric surgery, the patients had lost 58% excess body mass index with improvement in the HOMA-IR (3.0 ± 1.4 versus 1.1 ± .7; P.001). Measures of RR variation during deep breathing and total spectral power, low frequency (LF) power (influenced by sympathetic and parasympathetic activity), and high frequency (HF) power (parasympathetic activity) increased with weight loss. The LF/HF ratio was lower (1.5 ± 1.5 versus .9 ± .7, P.05) with a reduction in weight. Spectral analysis of HRV combined with spectral analysis of respiratory activity generated the respiration frequency area (RFA) and low frequency area. The RFA was increased, and the LFA/RFA ratio was reduced with weight loss. HOMA-IR and HRV did not correlate.Surgically induced weight loss has a favorable effect on autonomic function, but it does not appear to be directly attributable to reduced insulin resistance.

Islet amyloid, a pathologic feature of type 2 diabetes, contains the islet β-cell peptide islet amyloid polypeptide (IAPP) as its unique amyloidogenic component. Islet amyloid also contains heparan sulfate proteoglycans (HSPGs) that may contribute to amyloid formation by binding IAPP via their heparan sulfate (HS) chains. We hypothesized that β-cells produce HS that bind IAPP via regions of highly sulfated disaccharides. Unexpectedly, HS from the β-cell line β-TC3 contained fewer regions of highly sulfated disaccharides compared with control normal murine mammary gland (NMuMG) cells. The proportion of HS that bound IAPP was similar in both cell lines (∼65%). The sulfation pattern of IAPP-bound versus non-bound HS from β-TC3 cells was similar. In contrast, IAPP-bound HS from NMuMG cells contained frequent highly sulfated regions, whereas the non-bound material demonstrated fewer sulfated regions. Fibril formation from IAPP was stimulated equally by IAPP-bound β-TC3 HS, non-bound β-TC3 HS, and non-bound NMuMG HS but was stimulated to a greater extent by the highly sulfated IAPP-bound NMuMG HS. Desulfation of HS decreased the ability of both β-TC3 and NMuMG HS to stimulate IAPP maximal fibril formation, but desulfated HS from both cell types still accelerated fibril formation relative to IAPP alone. In summary, neither binding to nor acceleration of fibril formation from the amyloidogenic peptide IAPP is dependent on overall sulfation in HS synthesized by β-TC3 cells. This information will be important in determining approaches to reduce HS-IAPP interactions and ultimately prevent islet amyloid formation and its toxic effects in type 2 diabetes.

The present paper is dedicated to the application of the pivoted Cholesky decomposition to compute low-rank approximations of dense, positive semi-definite matrices. The resulting truncation error is rigorously controlled in terms of the trace norm. Exponential convergence rates are proved under the assumption that the eigenvalues of the matrix under consideration exhibit a sufficiently fast exponential decay. By numerical experiments it is demonstrated that the pivoted Cholesky decomposition leads to very efficient algorithms to separate the variables of bi-variate functions.

Real earnings management (REM) is an increasingly common method of manipulating financial results, yet little research examines auditors’ perceptions of and responses to REM. Using the auditor comfort framework (Pentland 1993; Carrington and Catasus 2007), we examine the extent to which REM impacts auditor comfort and how, in the presence of REM, auditors rely on comfort-building strategies in trying to move from a state of discomfort (i.e., fear of failing to identify misstatements) to comfort. Based on in-depth interviews of 20 experienced auditors, we find that auditors are aware of REM and often identify REM through formalized protocols that include analytical procedures, discussions with management, or their knowledge of the business. Formal audit procedures play a role when trying to address, “rationally,” the risk of REM, but we also find that auditors use emotive phrases and references to body senses related to discomfort, indicating that there also is an emotional component to dealing with REM (Guenin-Paracini, Malsch, and Paille 2014). Most of the interviewees have concerns about REM (i.e., it threatens comfort), largely because they believe that it is indicative of management’s desire to meet short-term targets (i.e., poor management tone), and that it may signal the use of other, less acceptable earnings management methods (i.e., accruals-based earnings management) to meet those targets. Interviewees respond to the discomfort caused by REM in many ways, including engaging in discussions with the client, increasing skepticism, and altering audit procedures and risk assessments. Auditors may even go as far as resigning from an engagement because of REM. Our analysis reveals that REM is a significant source of auditor discomfort and that auditors use both their rationality and their emotions/body senses to identify and try to alleviate that discomfort.

Although real earnings management (REM) is increasingly common, limited research examines how auditors react when they know or suspect that their clients are using REM. In addition, prior research on whether auditors react to REM is not conclusive, nor does it provide strong insights into why auditors would react to REM, given that REM does not violate GAAP. We conduct a 2x3 between-subjects experiment (client Beat or Missed the analysts’ consensus forecast, with three levels of REM: Explicit REM, Potential REM, and No REM) with highly experienced auditors as participants to examine the conditions in which auditors are sensitive to REM. Informed by Correspondent Inference Theory, we predict and find evidence that, when a client beats an EPS target, auditors observing Explicit REM perceive the weakest management tone and assess the highest levels of risk, followed by those observing Potential REM, and then those observing no REM. However, we predict that, when a client misses an EPS target, auditors are less likely to view Potential REM as actual REM. Thus, we find that, when a client misses an EPS target, auditors observing Explicit REM perceive weaker management tone and assess higher levels of risk relative to when they observe Potential REM or when REM is absent. Further, when clients miss the EPS target, we find that auditor responses to Potential REM do not differ from when REM is absent. Finally, we find that auditors’ perceptions of management tone mediate the relation between REM and risk assessments. Overall, the results are consistent with Correspondent Inference Theory and demonstrate how and why auditors respond to REM.

The Midwest floods of 1993 presented multiple emergency preparedness challenges to the six metropolitan medical centers in Des Moines, Iowa. As floodwaters overcame the Des Moines Water Treatment Plant, medical centers were faced with the task of responding to imminent water loss and its associated impact on patient care services and facility operations. Many clinical services were cancelled or diverted to alternate facilities. Ancillary resources were identified and implemented to maintain essential operations. Through effective emergency preparedness and creative improvisation, medical centers were able to overcome the initial crisis, sustain primary services, and ensure continued quality patient care. The article describes how sudden and prolonged water loss affected Des Moines hospitals. It also discusses aspects of hospital emergency preparedness that contributed to successful response.

Recent technological developments create the need for new ventures to monitor the market environment. The various techniques used to acquire market information differ depending on the venture but are related to the ultimate success of the new venture. This exploratory research investigates market information scanning practices in a sample of 120 new ventures. Types, methods, and sources of market information are compared in service and manufacturing ventures, and relationships between these practices and growth are assessed. Results of X 2 tests show selective differences between service and manufacturers as a whole and when growth is considered. Multiple regression analysis showed manufacturers experiencing growth acquired information about competitors' sales and market share and depended on personal contacts and networks. Scanning activities were not highly related to growth in service firms.

We used Monte Carlo simulations (MCS) to study the transport of ions through single and dual frequency, multicomponent plasma sheaths during plasma enhanced deposition of silicon dioxide from TEOS and oxygen mixtures (PETEOS). First, we used our dual frequency plasma sheath model (DFPSM) to predict the potential as a function of position and time and the sheath thickness as a function of time. We then performed the Monte Carlo simulations to determine the angular and energy distribution functions for a selected species striking the substrate, taking into account a variety of collision types. Our DFPSM predictions as well as our distribution function predictions are in reasonable agreement with most available experimental data. These is little experimental information available with which to compare our multicomponent and dual frequency predictions; however, the trends observed are consistent with explanations often used to interpret trends in film properties.

A two-stage screening procedure is developed for a situation where an item is sold in one of two markets or scrapped. The item's selling price and product specifications are different in both markets. In the first stage of the procedure, each item is inspected on a surrogate variable that is correlated with the perfornance variable of interest. If a decision is not reached at this point, the item is subjected to the second-stage of the procedure where it is inspected on the performance variable, and a classification decision is made. A loss in revenue is incurred by the producer when an item that meets the specifications of the higher-price market is sold in the lower-price market. The producer also sustains a cost when an item that does not conform to the product specifications of a market is sold in that market. The economic factors considered in the model, therefore, are the selling prices and the cost consequences resulting from decision errors. The optimal screening specification limits for known-parameter and unknown-parameters situations are derived by maximizing the expected profit per item.

In a previous paper (1) the effects of particle inertia on the diffusional deposition of Brownian particles onto a surface in viscous, axisymmetric stagnation-point flow were investigated using the method of Brownian dynamics. Following Fernandez de la Mora and Rosner (2), under the conditions of large Schmidt numbers and small Stokes numbers (less than the critical Stokes number), an approximate analytical solution is obtained here that also includes an arbitrary external force acting on the particles. This solution is shown to be in excellent agreement with the results from Brownian dynamics simulations. An important characteristic of these solutions is inertial particle concentration “enrichment” outside the diffusion boundary layer near the adsorbing surface at subcritical Stokes numbers. In general, it is shown that attractive external particle forces only slightly reduce the amount of this enrichment. On the other hand, in the absence of inertia, attractive external particle forces increase the surface flux of particles beyond that for solely diffusional deposition. The combination of inertial particle concentration enrichment and an attractive external particle force leads to a synergistic-type increase in the surface flux of particles beyond that for solely diffusional deposition. Finally, Robinson's theorem (6) is extended to formally prove these results for inviscid-type flows.

By raising the temperature of a surface above that of the ambient fluid, a temperature gradient that results in a thermophoretic force that repels particles from the surface is created. It has been recommended that this effect be used to reduce the contamination of product surfaces during manufacturing. It has been shown that even modest levels of electrostatic interactions between particles and surfaces can overwhelm the thermophoretic repulsion available by raising the temperature of the surface 10% above that of the ambient fluid. We present an analysis for axisymmetric, viscous stagnation-point flow, extending the work of Friedlander et al. (1988, J. Colloid Interface Sci.125, 351), and show the temperature differences that must be achieved to succeed in preventing particle deposition due to diffusion, gravitation, and electrostatic attraction. Simple algebraic relationships are established that allow for a ready determination of the temperature differences needed to suppress particle diffusional deposition onto surfaces under the action of uniform external forces, such as gravitational and coulombic forces, and a spatially dependent external force, which for this study we have chosen to be the electrostatic image force. These relationships are further verified through approximate analytical and “exact” numerical solutions also given here. Various results of practical interest are discussed. For example, for a flow intensity of 6.67 s−1 in air, an electric field as small as 100 V/cm makes it unlikely that particles with a minimal charge distribution (Boltzmann) will be kept from deposition on a surface by raising the surface temperature 10 or 20% above the ambient temperature. This emphasizes the importance of reducing the electric charge levels of product surfaces during manufacturing.

PECVD techniques have been used to deposit polycrystalline diamond films that have material properties nearly identical to those of natural diamond. Diamond is the hardest known material and has the highest thermal conductivity at room temperature, while the undoped material is an excellent insulator. These and other mechanical, chemical and electrical properties make diamond films attractive for use in applications such as optics, electronic packaging and parts with low wear rates. An X-ray window device has been fabricated using a diamond window and a micromachined silicon substrate.

Background The 3-gene signature of periostin, chloride channel accessory 1 (CLCA1) , and Serpin β2 (SERPINB2) in airway epithelial brushings is used to classify asthma into T H 2-high and T H 2-low endotypes. Little is known about the utility of gene profiling in sputum as a molecular phenotyping method. Objective We sought to determine whether gene profiling in sputum cells can identify T H 2-high and T H 2-low subtypes of asthma. Methods In induced sputum cell pellets from 37 asthmatic patients and 15 healthy control subjects, PCR was used to profile gene expression of the epithelial cell signature of IL-13 activation (periostin, CLCA1 , and SERPINB2 ), T H 2 genes ( IL4 , IL5 , and IL13 ), and other genes associated with airway T H 2 inflammation. Results Gene expression levels of CLCA1 and periostin, but not SerpinB2, were significantly higher than normal in sputum cells from asthmatic subjects. Expression levels of IL-4, IL-5, and IL-13 were also significantly increased in asthmatic patients and highly correlated within individual subjects. By combining the expression levels of IL-4, IL-5, and IL-13 in a single quantitative metric ("T H 2 gene mean"), 26 (70%) of the 37 asthmatic patients had T H 2-high asthma, which was characterized by more severe measures of asthma and increased blood and sputum eosinophilia. T H 2 gene mean values tended to be stable when initial values were very high or very low but fluctuated above or below the T H 2-high cutoff when initial values were intermediate. Conclusion IL-4, IL-5, and IL-13 transcripts are easily detected in sputum cells from asthmatic patients, and their expression levels can be used to classify asthma into T H 2-high and T H 2-low endotypes.

We investigate whether analysts' common-stock valuation judgments are predictably affected by (1) different methods of accounting for business combinations and (2) the number of years that elapse after the business combinations occur. Numerous articles in the business press suggest that companies go to great lengths to avoid amortization of the purchase-method acquisition premium, either by structuring acquisitions to qualify for pooling treatment or aggressively allocating the acquisition premium to "in-process" research and development (IPRD) and immediately expensing it. Firms' reluctance to capitalize and amortize the acquisition premium often is based on their managers' belief that amortizing the acquisition premium impairs firm value, especially in years subsequent to the transaction. However, research to date neither refutes nor defends this belief. We report the results of an experiment in which 113 buy-side equity analysts participated. Consistent with our expectations, analysts' post-combination valuation judgments are lower when a parent company records and amortizes an acquisition premium in a purchase-method business combination and equivalently higher when the company either immediately expenses the entire purchase-method acquisition premium as IPRD or records the business combination using the pooling-of-interests method. In addition, in the case where the parent company records and amortizes an acquisition premium in a purchase-method business combination, analysts' stock-price judgments are significantly lower if the business combination occurred three years ago as compared to one year ago. We also test the FASB's proposal to report separate sub-totals (and related EPS figures) for pre-goodwill-amortization operating income, after-tax goodwill amortization, and net income. Our results suggest that the Board's proposed goodwill-reporting format mitigates the valuation difference between combinations that occurred one-year ago versus three-years ago. We discuss the implications of this study for users of financial accounting information and for accounting standard setters.

Previous studies on the adsorption or deposition of Brownian particles onto surfaces have been carried out in the limit of infinite particle dilution. In the present study we have examined the effects of finite particle concentrations on the transport and adsorption of Brownian particles onto surfaces. A macroscopic diffusion equation for the collection of particles in a nonuniform host fluid is derived beginning with the n -particle Fokker-Planck equation. Both hydrodynamic interparticle interactions and hydrodynamic interactions of the particles with the adsorbing surface are included in the theoretical formulation. In agreement with previous methods, the resulting convective-diffusion equation is similar in form to the single-particle equation (Smoluchowski equation) with the Einstein diffusion coefficient replaced by the mutual diffusion tensor for the interacting Brownian particles. Solutions to the convective-diffusion equation were carried out for the problem of Brownian particle adsorption onto a large sphere under the conditions of low Reynolds number fluid motion and large particle Peclet numbers. In this first study, we have neglected the effects of hydrodynamic interactions on the solution behavior, and have thus focused our attention on the effects of attractive- and repulsive-type colloidal force interactions on the transport and deposition of Brownian particles onto a spherical collector. Our semianalytic solutions to the convective-diffusion equation show a general behavior of interparticle interactions: attractive-type interactions lead to a decrease in the total particle number flux to the sphere surface as compared to the noninteracting case, whereas repulsive-type interactions result in a relative increase in the flux. This behavior is explained by examining the “force environment” of a particle near the collecting sphere surface. The effects of colloidal interaction forces were further quantified by considering two specific interaction potentials: hard-sphere and electric double-layer interactions. Typical parameters of this latter potential show a most dramatic change in the total particle number flux, resulting in some cases in as much as a 100% increase over the noninteracting case at a particle volume fraction of 10 −2 . Finally, we have also summarized our assumptions which have led to the results reported here, including the neglect of hydrodynamic interactions to be investigated in the second part of this study.

The inclusion of Brownian motion in aerosol deposition studies has often been treated separately from deposition due to other causes (e.g., inertial and electrical forces). A unified approach based on the full solution to the so-called ordinary Langevin equation of motion is presented to study particle deposition on a single spherical collector. The “Brownian dynamics” method given here is useful when the inertial, external, and particle-particle interaction forces are comparable to the diffusive, or Brownian, force. Several example calculations are considered for both the clean, or steady-state, deposition efficiencies, as well as for the unsteady-state efficiencies (particle-particle deposition problem). In particular, for the steady-state behavior, the classic Levich-Lighthill solution to the problem of convective-diffusion to a freely falling sphere has been reproduced. Additionally, an approximate analytical solution for the combined case of inertial and diffusional deposition, recently given by J. Fernandez de la Mora and D. E. Rosner [J. Fluid Mech. 125, 379 (1982)], has been verified and the so-called principle of superposition for the combined case of inertial and electrostatic deposition has been criticized. For the unsteady-state problem, the charge neutralization of an initially uniform charged collecting sphere by the deposition of oppositely charged Brownian particles has been examined. This latter study represents a generalization of the previously proposed “aerosol dynamics” method (M. H. Peters, R. K. Jalan, and D. Gupta, Chem. Eng. Sci., in press) which now includes the Brownian motion of the aerosol particles.

Fine particles can deposit on microelectronic parts during their manufacture and cause damage. Prediction of the rates of deposition is important in planning to reduce such losses. Analytic expressions were developed and Monte Carlo simulations (Brownian dynamics) were carried out to predict deposition rates of sub-micron particles in viscous axisymmetric stagnation point flow. Diffusive, inertial and electrostatic deposition mechanisms were incorporated in the analysis. The electrostatic forces considered included the Coulombic force on a charged particle in an electric field and the image force on a charged particle near a conducting plane. Analytical solutions to the convective-diffusion equation, in the absence of inertial effects, showed that for a Boltzmann charge equilibrium, the electrostatic image force did not appreciably enhance deposition for a free-stream velocity of 50 cm s−1. However, the Coulomb electrostatic attraction of a charged particle towards a charged surface greatly enhanced deposition, assuming a field from the disk approximately equivalent to having a disk 20 cm in diameter (80 pF capacitance) at 2000 V. Some areas for future study are suggested by these results. Brownian dynamics simulations carried out for particles of the order of 1 μm in diameter at a much higher velocity (30 m s−1) demonstrated an interaction between inertial and diffusive deposition that produced inertially enhanced deposition at Stokes values below the critical value, St

We have considered asymptotic solutions at large bubble Reynolds number to the energy transport equation describing the spatial variation of the “granular temperature” in the flow field around a single bubble in a gas fluidized bed. The granular temperature represents the mean peculiar kinetic energy of the particle phase, and is necessary in a “complete” description of the fluid-particle transport phenomena. In the present case of single-bubble motion, the energy source is from the particle-phase viscous dissipation term. At large bubble Reynolds numbers, viscous effects are confined to a thin boundary-layer region, as in the case of a gas bubble in a liquid. It is demonstrated that the Prandtl number for this problem is O(1), or that the momentum and “thermal” particle-phase boundary layers are of the same order of magnitude. The thermal boundary-layer equation for the granular temperature is subsequently derived and solved analytically. It is assumed that outside the thermal boundary layer, where viscous effects are negligible, the granular temperature is zero. From the mathematical solutions to the energy transport equation associated with single-bubble motion, including viscous dissipation terms and utilizing relationships from the kinetic theory of dense gases, we have given analytical expressions for the effective particle-phase shear viscosity and the effective particle-phase hydrostatic pressure, the two properties which characterize the kinetic component of the particle-phase pressure tensor. The theoretical results show remarkably good agreement with reported experimental measurements of the above properties.

In the present study a greatly simplified method is outlined for the prediction of the transient behavior of particle deposition on a spherical collector, taking into consideration a variety of force terms, such as inertial, electrostatic, drag, and gravitational forces. The technique developed, which utilizes the stochastic simulation procedure of Tien et al.[10], is based on the concept of discretizing the fluid control volume into small cubical elements of the same size as the particles. This allows for a ready determination of both primary collection (particle deposition on the collecting sphere) and secondary collection (particle deposition on previously deposited particles). The aerosol dynamic simulations are used to study the important phenomena of the charge neutralization of a collecting sphere by the deposition of oppositely charged particles. The methodology given may be of interest in the study of particle filtration and particle coating processes.

To investigate the possible role of adrenergic nerves in neurally mediated gastrin release, we evaluated the effect of selective adrenergic blockade on the serum gastrin response to gastric distention in healthy human subjects. On separate days, 2 mg of propranolol (beta-adrenergic antagonist), 5 mg of phentolamine (alpha-adrenergic antagonist), or saline (control) was injected intravenously just before distending the stomach with 700 ml of isotonic saline. For 30 min following distention, intragastric pH was kept constant at 5.0 by in vivo titration. Propranolol reduced distention-induced gastrin release by approximately 90% (p less than 0.02), whereas phentolamine had no significant effect on the gastrin response to distention. In additional experiments, we evaluated the effect of the same doses of propranolol or phentolamine on the exaggerated gastrin response to gastric distention that occurred during cholinergic blockade with atropine. In the presence of atropine (2.3 microgram/kg i.v.), propranolol significantly (p less than 0.01) reduced distention-induced gastrin release, whereas phentolamine significantly enhanced the gastrin response to distention (p less than 0.01). We conclude that: (1) distention-induced gastrin release was reduced by propranolol, suggesting that gastric distention releases gastrin by a beta-adrenergic mechanism and (2) distention-induced gastrin release was enhanced by phentolamine, but only in the presence of atropine. Thus, adrenergic nerves appear to regulate the gastrin response to gastric distention in humans: beta-adrenergic pathways stimulate gastrin release, and alpha-adrenergic pathways may inhibit gastrin release under certain circumstances.

We have evaluated 2 patients with symptomatic gastric disease who dated the onset of their illnesses to stressful events in their lives. In 1 patient, six family members had recently died and our patient feared that he too would die. The other patient was accused of grand theft, was under police surveillance, and had lost his job. Both patients had markedly increased gastric acid secretion rates that decreased to normal after hospitalization and reassurance in the first case and acquittal in the second case. Ulcer symptoms subsided at the same time as the decrease in acid secretion. Although we cannot prove that severe emotional stress in our patients led to acid hypersecretion and ulcer disease, their courses suggest that stressful life events caused increased acid secretion which, in turn, led to ulceration and symptoms.

A new method of fitting particle trajectories in non-uniform magnetic fields is described. It is assumed that measured points in three-dimensional space have already been obtained. The trajectory is broken into segments within which the magnetic field may be regarded as a linear function, for which an approximate analytic form of the trajectory is derived. With this form and its derivatives, a Newton-Rapheson iteration is carried out to minimize the sum of the squares of deviations of observed points from the trajectory. The method described has been used in a spark chamber experiment investigating K e4 and K πee decays.