cssi/SciSciGPT-SciSciNet huggingface dataset:
Cerebrovascular responses to pentylenetetrazol: time and dose dependent effects.

Abstract The effects of subconvulsant and convulsant doses of pentylenetetrazol (PTZ) on cerebral blood flow (rCBF), permeability-capillary surface area products (rPS), and brain vascular spaces (BVS) were examined in 15 brain regions at 1 h, 24 h and 1 week after injection in male Sprague-Dawley rats. Brain histology was examined 3 days after injection. A dose of PTZ (50 mg/kg, i.p.), sufficient to trigger a single convulsive seizure, produced small regional changes in rCBF at 1 h, but not at 24 h or 1 week after injection. No significant changes in rPS or BVS were found at any time, and only mild histologie changes were observed. In contrast, a dose of PTZ (25 mg/kg) which failed to cause either convulsions or significant electrocorticographic changes, markedly increased rCBF and rPS. Some of these regional effects were still observed 1 week later. Similarly, more severe and extensive cellular changes followed treatment with the subconvulsive dose. These findings indicate that PTZ treatment can have prolonged effects on Cerebrovascular functions and neuronal integrity even in the absence of convulsive activity.
A comparison of the oxygen affinity of maternal and fetal blood of the Macaca mulatta.

Constants relating the oxygen tension, percentage oxygen saturation and pH in the blood of maternal and fetal Macaca Mulatta (Rhesus) monkeys have been determined. Half saturation of the blood with oxygen is obtained at PO2's of 27·0 and 16·0 mm. of mercury in maternal and fetal blood respectively, at pH 7·40. The effect of pH changes upon the oxygen dissociation curves, and the slopes of these curves, were found to be identical in maternal and fetal blood. A comparison of the oxygen affinities of these bloods was made with those of other species, and the differences discussed.
A study of zinc in human teeth.

Abstract Zinc accumulates in the surface structures of teeth and occurs in low concentrations in subsurface material, thus exhibiting a distributive pattern similar to that of fluoride and lead. Concentrations of zinc in surface enamel of teeth from different areas range from 430 to 2100 p.p.m. In terms of molar concentrations the concentrations are frequently of the same order as those of fluoride. In enamel the major deposition of zinc takes place before tooth eruption. In contrast to fluoride, posteruptive deposition of zinc appears to be irregular. Zinc is readily acquired by synthetic hydroxyapatite, competing with calcium for positions on the surface of the apatite crystal. Zinc pretreatment of hydroxyapatite produces a resistance to acid dissolution similar in magnitude to that produced by equivalent molar concentrations of fluoride.
The early evolution of the surface of hydrating cement

The development of surface area during the hydration of Portland cement has been followed by small angle x-ray scattering for times ranging from 10 minutes to 1 year. Up to the time of initial set little change in surface area is observed. After final set surface area develops steadily with time to an upper value of about 600 m2/g (dry basis) after one year. The results are correlated with isothermal conduction calorimetry and compared with other investigations of surface area development.
The Fermi-sea-like limit of the composite fermion wave function

The experimentally observed filling factors of the fractional quantum Hall effect can be described in terms of the composite fermion wave function of the Jastrow-Slater form [0pt] fully projected into the lowest Landau level. The Slater determinant of the above composite fermion wave function represents the filled Landau levels of composite fermions evaluated at the corresponding reduced magnetic field. For a system of fermions studied in the thermodynamic limit, we prove that in the even-denominator-filled state limit (when the number of filled Landau levels of composite fermions becomes infinite), the above composite fermion wave function exactly transforms into the Rezayi-Read Fermi-sea-like wave function [0pt] constructed by attaching 2m flux quanta to the Slater determinant of two-dimensional free fermions at the density corresponding to that filling. We study the composite fermion wave function and its evolution into the Fermi-sea-like wave function for a range of filling factors very close to the even-denominator-filled state.
108. Study of an AAV-8 Capsid Mutant with Direct Heparin Binding Capability but Reduced Efficiency in Liver-Targeted Transduction

Top of pageAbstract AAV vectors pseudotyped with the AAV-8 capsids have become a popular alternative to the more extensively studied AAV-2 vectors due to their more robust transduction of liver and other targets in vivo. Importantly, liver transduction with AAV-2 is significantly higher when the vector is administered into the liver vasculature compared to a peripheral venous infusion (e.g. tail vein). In contrast, there are no differences in liver transduction efficiencies when AAV- 8 vectors were administered via these two different routes. Despite the high degree of sequence homologies (|[sim]|83%), the two capsids differ in their cell surface binding properties. Because wild type AAV-8 cannot directly bind to heparin, whose analog, heparan sulfate proteoglycan (HSPG), is a primary cell surface receptor for AAV-2, we hypothesized that the heparin binding motif may play a role in the observed differences in the hepatic transduction parameters. Sequence alignment revealed that the AAV-8 cap gene lacks two basic amino acid residues found in AAV-2 (R585, R588) that are essential for heparin binding. By substituting the corresponding AAV-8 residues at these and neighboring positions with AAV-2 sequence, we generated a mutant AAV-8 (mAAV-8) capsid with direct heparin-binding affinity similar to that of AAV-2. We made liver-specific human factor IX (hFIX)-expressing vectors in AAV-2, AAV-8 or the mAAV-8 capsids respectively, and compared their liver transduction efficiencies following intravenous administration into C57BL/6 mice. Depending on the route of injection, hFIX expression levels from the mAAV-8 vector were three and ten times lower than that of AAV-8 when administered via portal vein and tail vein, respectively. These differences in transduction with peripheral and liver vascular infusions were similar to what we observed with AAV-2, suggesting that the heparin binding motif may influence differing transduction efficiencies when administered by different vascular routes. To further establish this possibility, vector bio-distribution in various tissues was also checked by real-time PCR quantitation of viral genomes at different time points following vector administration. We found that the mAAV-8 capsid showed broader tropism and less targeting in the liver when administered via tail vein. Further experiments are being carried out to examine the intracellular trafficking pathways of vectors made with each of these capsids but our results suggest that vector biodistribution and perhaps intracellular transduction pathways are influenced by the presence of the heparin binding motif.
Nothing: A User's Manual

In introducing this enigmatic topic, I often begin with a riddle that points to its elusive, mobile character: What is greater than God, more powerful than evil, the rich have it, the poor need it, and if you eat it, you die? -Nothing. In the multiple contexts in which I've navigated the topic of nothing (course, conference, collection of essays, special issue), it has proved a subject that provokes mirth, irony, and skepticism. When I have told colleagues that I'm teaching "A Course About Nothing," the responses I get range from "Oh...it must have a short reading list," to "Well, I'm going to teach my class now-at least it's about something," to "Uhhuh" or just "Huh." (I have a slight preference for "huh" because it is linked to nothing through its palindromic symmetry (h-u-h), plus it is resolutely noncommittal; it says nothing.) And when I sent out a Call for Papers for this special issue, several people thought it was a hoax; I received many responses that said, "Dear Dr. Harris, please find below my submission for your journal issue," with the rest left blank. Still others wondered whether the topic of Nothing could lead to anything but more postmodern nihilism or empty intellectual solipsisms. Finally, on a pragmatic, pedagogical level, in setting out to investigate Nothing, one faces fundamental questions regarding both the utility and the futility of the topic. On the one hand, of what use could it be to pursue Nothing? And on the other, how can any search for it, any attempt to define or capture it, end up in anything but futility? While I have obviously not found definitive answers to these queries, I would maintain that a preliminary way of responding to them has emerged from teaching a class on Nothing. The use of Nothing lies in the simple fact that reading and thinking and talking about it leads down paths one would otherwise never traverse, and in following these lines of thought, one begins to develop a different way of thinking. This mode of reflection strives to avoid approaching Nothing from a standpoint grounded in the world of Being, where Presence and Something are presupposed to exist, and Nothing is seen as nothing but nonbeing. It is
An analytic-asymptotic approach for time-harmonic nonsymmetric wave propagation in a cylinder

A solution approach for general nonsymmetric time-harmonic end problems is demonstrated for a semi-infinite isotropic solid circular cylinder which is traction-free on its cylindrical surface. The present solution technique is an extension of that used in Kim and Steele (1989a, J. Appl. Mech. 56, 334–346) for longitudinal axisymmetric wave propagation in a cylinder. In the present solution procedure, the end displacement and traction are expanded by the series found by Kim and Steele (1989b, J. Appl. Mech. 56, 910–917), and the end stiffness matrix is formed. The insensitive nature of the solutions at the end of the cylinder to cylindrical surface conditions, as observed by Kim and Steele (1989b), is utilized in the present solution procedure. The effectiveness of the approach is demonstrated by an example of localized eccentric loading of the end.
Scepticism and the framework‐relativity of enquiry

Many argue that sceptical enquiry is incoherent insofar as it requires a detachment from and assessment of the framework judgements that constitute our practice of enquiry. This paper accepts that enquiry is relative to a framework, but argues that the Cartesian sceptical enquiry is consistent with that relativity. Part I presents Marie McGinn's Wittgen-steinian anti-sceptical argument, comparing its view of enquiry to Carnap's. Part II clarifies the sense in which Wittgenstein's ‘Moore-type’ framework judgements could be unquestionable, and argues that McGinn's antisceptical argument fails. Part III shows that the sceptical enquiry finds all our beliefs to lack justification by suspending our normal non-sceptical framework judgement regarding perception in a way that is consistent with the framework-relativity of enquiry, and encouraged by normal standards. The paper closes by recommending a view of scepticism as a stimulus for enquiry.1
A numerical case-study of the squall line of 6 may 1975

Abstract Results of moist and dry fine-mesh (∼140 km) numerical simulations of the 6 May 1975 Omaha squall line are presented. The moist fine-mesh simulation reproduced several observable features of the squall system and was then used to study other unobservable features. Differential thermal advection was responsible for the creation of potential instability. Low-level horizontal thermal advection contributed to pressure falls which, in turn, enhanced the convergence into the warm tongue. These processes initiated a band of convection. Results of the dry simulation suggested that the location and orientation of the initial low-level convergence was determined by dry mechanisms, that the convective latent heat release increased the rate of cyclonic-scale occlusion and that the occlusion process was followed by the dissipation of the convection. In addition to the fine-mesh simulations, a meso-mesh (∼35 km) simulation was conducted. Because of the increased resolution, this simulation was able to reproduc...
BENCHMARKING FOR AGILITY

Agility and agile manufacturing are recent organizational development philosophies that industry and academia are studying. Benchmarking is a business practice that will aid in the study, refinement, and application of agility principles. This paper focuses on two issues, benchmarking agile environments and agile benchmarking requirements. Benchmarking process, tools and metrics issues are discussed within the perspective of agility requirements. The process, tools and metrics discussion allows for a simultaneous study of the two major issues in integrating benchmarking and agility. In this paper a need for a developmental evolution in benchmarking is also observed. A number of potential directions and enablers are defined based on current practice and emerging mechanisms for agility and benchmarking.
INSTITUTIONS AND ECONOMIC PERFORMANCE: CROSS‐COUNTRY TESTS USING ALTERNATIVE INSTITUTIONAL MEASURES

This paper compares more direct measures of the institutional environment with both the instability proxies used by Barro (1991) and the Gastil indices, by comparing their effects both on growth and private investment. The results provide substantial support for the position that the institutional roots of growth and convergence are significant. The marked improvement that these new variables represent over existing proxies also suggests that there are substantial returns to future research into variables that reflect the security of property rights and the efficiency with which states determine economic policies and allocate public goods.
Phase variation in Bordetella pertussis by frameshift mutation in a gene for a novel two-component system

Bordetella pertussis, the aetiological agent of whooping cough, coordinately regulates the expression of many virulence-associated determinants, including filamentous haemagglutinin, pertussis toxin, adenylyl cyclase toxin, dermonecrotic toxin and haemolysin. The coordinate regulation is apparent in the repression of synthesis of these determinants in response to environmental stimuli; a phenomenon known as antigenic or phenotypic modulation. B. pertussis also varies between metastable genetic states, or phases. There is a virulent phase in which virulence-associated determinants are synthesized, and an avirulent phase in which they are not. Previous studies have shown that a genetic locus, vir, is required for expression from many virulence-associated loci, and that replacing the cloned vir locus in trans can restore the virulent phase phenotype to spontaneously occurring avirulent phase strains. Here, we show that phase variation in one series of strains is due to a frameshift mutation within an open reading frame that is predicted to code for a Vir protein product. The deduced protein sequence is similar to both components of the 'two-component' regulatory system which control gene expression in response to environmental stimuli in a range of bacterial species.
Note on a Test for Trend in Binomial Proportions Using Ranks

For a 2xk contingency table when all the k groups fall into a natural order and for which a sequence of k values × may be assigned, ARMITAGE (1955) has suggested a X2(1) test statistic for the hypothesis Ht of a trend in the proportions; This note considers a statistic for Ht based on midrank values for the binary observations. It is shown that the proposed rank-order test for Ht coincides with that of ARMITAGE (1955).
An inexpensive potentiostat for controlled cathode-potential electrolyses

Abstract The construction of a simple potentiostat from inexpensive components is described. Satisfactory results were obtained in the controlled cathode-potential coulometry of submillimolar amounts of copper(II), cobalt(II), 2,2-dinitropropane, and m -dinitrobenzene.
Cyclic Behavior of Steel Wide-Flange Columns Subjected to Large Drift

During an earthquake, steel braced frame columns can be subjected to high axial forces combined with inelastic rotation demand resulting from story drift. Cyclic testing of nine full-scale W14 column specimens representing a practical range of flange and web width-to-thickness ratios were subjected to different levels of axial force demand (35, 55, and 75% of nominal axial yield strength) combined with up to 10% story drift. No global buckling was observed in all test specimens. Flange local buckling was the dominant buckling mode. Specimens achieved interstory drift capacities of 0.07– 0.09 rad . These large deformation capacities were, in part, achieved due to the delay in flange local buckling resulting from the stabilizing effect provided by the stocky column web of the W14 section specimens. Testing indicated that the ASCE 41 predicted plastic rotation capacities are very conservative. The ASCE 41 criteria do not specify plastic rotation capacity at axial load ratios greater than 0.5; however, tested...
ISDN frame relay and its congestion control

Frame relay is a new ISDN (integrated services digital network) packet mode bearer service which is expected to provide an efficient means of information transport using high-speed transmission media. Several new applications requiring high bandwidth, such as file transfer, video and packetized voice, are suitable candidates to use this streamlined protocol. However, as there are no control frames present within the network for traffic flow management, congestion may arise during periods of peak offered loads. Efficient congestion control mechanisms are needed to make the frame relay effective. In this paper, after a brief discussion of the frame relay protocol, we consider the congestion problem in networks using this protocol and evaluate the performance. Specifically, we consider static and dynamic window flow control methods and develop models to determine the throughput under various load conditions. The throughput of the static window flow control model is determined by computing the frame loss probability and the virtual retransmission time, which is the time between arrivals of retransmitted frames at the destination. The frame loss probability is calculated by modelling the bottleneck resource as a finite state Markov chain. The results are validated by simulation. Furthermore, to analyse the dynamic interactions between the virtual circuits and their effect on the throughput and delay characteristics, we develop a simulation model which incorporates a dynamic window congestion control mechanism. It is shown that when the offered load is high, the performance of dynamic window flow control is superior to that of static window flow control.
Free topological groups

Abstract Main Theorem. The free abelian topological group over a Tychonoff1 space contains as a closed subspace a homeomorphic copy of each finite power of the space. A major and immediate corollary of this theorem is: If P is a closed hereditary property of Tychonoff spaces, and if the free abelian topological group over a Tychonoff spaces has P , then so does every finite power of the space. In particular, the corollary shows that the following properties are not preserved by passage to the free abelian group: normal, k- sequential, Frechet, Lindelof, paracompact, pseudocompact, countably compact, sequentially compact, etc.
Teaching the Relevance of Statistics Through Consumer-Oriented Research

Students in a small experimental design class obtained information about statistical and research applications concerning a variety of products advertised by different companies. The resulting data were perceived to have several advantages for the students: (a) it made collecting and interpreting data more interesting and less mysterious, (b) it helped them to understand how research design and statistics are used in real-life situations, and (c) it helped them to make more discerning judgments about advertisers' claims for their products.
Web 2.0 geospatial visual analytics for improved urban flooding situational awareness and assessment

Situational awareness of urban flooding during storm events is important for disaster and emergency management. However, no general purpose tools yet exist for rendering rainfall accumulations in real-time at the resolution of hydrologic units used for modeling. This demonstration will exhibit a novel web 2.0 visual analytical approach for understanding and adaptively managing urban flooding issues. The approach generates a geospatial-temporal map of rainfall within urban hydrologic units (sewer-sheds) in real-time. The polygon-averaged rainfall data is generated using virtual sensors which provide customized real-time data products derived from National Weather Service weather radar data using NCSA's workflow tools. Time-series KML (Keyhole Markup Language) layers are generated, where each KML layer represents a particular slice of the geospatial color-coded sewershed map. Such time-aware KML can be replayed as a movie in the web-based Google Earth environment. This geospatial visual analytic approach can provide decision markers and communities a powerful resource for assessment of neighborhood flooding issues. We will demonstrate our technology using historical and real-time rainfall data in the metropolitan Chicago area to show the effectiveness of such approach. Future work by combining additional ground-truth flooding data will allow us move towards real-time improved decision support for flooding and stormwater management.
Optimizing Dehydrators Operation Using Dynamic Adsorption Time

Molecular sieve is a solid deiccant widely used in gas plants for dehydrating wet process gases. Compared to other desiccants, molecular sieve can reduce water content in the outlet gas to less than 0.1 ppmv. This is a must requirement for conditioning feed gas to crypogenic applications. On the other hand, Molecular Sieve is generally more expensive and energy exhaustive.
Presidential plenary: Our feminist foremothers

This article provides a brief historical overview of the women researchers and popularizers of human sexuality during the 20th century. I look at some unique problems such women had and their success in overcoming obstacles.
Anesthetic Effects in Mice and Dogs of Some Unsaturated Hydrocarbons and Carbon-Oxygen Ring Compounds

Summary1. Anesthesia was induced in mice with 20 different compounds which were highly purified unsaturated hydrocarbons and carbon-oxygen ring compounds. Concentrations required for surgical anesthesia and for respiratory arrest were measured.2. Compounds with unsaturation in the 2 position in either the ethylene or acetylene series exhibited greater physiological activity than did corresponding compounds having unsaturation in the terminal position.3. Trimethylene oxide and 5 and 6 membered carbon-oxygen ring compounds were toxic.4. Where sufficient agent was available, sensitization of cardiac tissue of anesthetized dogs to epinephrine was determined. Irregularities of cardiac rhythm of at least moderate severity were produced with all 9 agents used except isobutylene which caused only mild tachycardia and minor voltage changes.
In the 25 years since The Mythical Man-Month what have we learned about project management?

This paper discusses Brooks’ The Mythical Man-Month , a landmark work in the software project management field, and compares the software project management advice given there with practices employed some 25 years later. To find out the state of today’s practice 20 experienced software developers were interviewed regarding their impressions of factors leading to success or failure of software development projects. Their observations are compared with the points raised by Brooks in his seminal work. q 1999 Elsevier Science B.V. All rights reserved.
Greed at Work: A Review and Assessment

This paper argues that current conceptions of greed, particularly in the workplace, may need improvement in several respects. A review of the literature indicates that while progress has been made ...
Neoadjuvant therapy for adenocarcinoma of the rectum: tumor response and acute toxicity.

PURPOSE: This study was designed to evaluate the down-staging effect and acute toxicity of preoperative radiation and chemoradiation for primary adenocarcinoma of the rectum. METHODS: The results of pretreatment staging with transrectal ultrasound and computed tomography were compared with final histologic stage in 260 consecutive patients who underwent neoadjuvant therapy and proctectomy for primary adenocarcinoma of the rectum. Patients underwent short-course radiation (2,000 cGy in five fractions), long-course radiation (4,500 cGy in 25 fractions), or chemoradiation (4,500 cGy in 25 fractions with concurrent chemotherapy). RESULTS: Down-staging of one or more T stages occurred in 116 of 260 (45 percent) patients overall (short-course radiation 34/82 (42 percent), long-course radiation 55/122 (45 percent), chemoradiation 27/56 (48 percent),P = not significant). Down-staging of one or more N stages occurred in 85 of 178 (48 percent) patients overall (short-course radiation 12/45 (27 percent), long-course radiation 49/86 (57 percent), chemoradiation 24/47 (51 percent),P=0.003). Complete pathologic response was observed in 16 of 260 (6 percent) patients overall (short-course radiation 4/82 (5 percent), long-course radiation 5/122 (4 percent), chemoradiation 7/56 (13 percent),P=0.08). Resection with negative margins (distal, proximal, and radial) was achieved in 211 of 227 patients (93 percent) in whom complete radial margin data were available. Permanent stomas were created in 35 percent of patients; temporary stomas were created in 15 percent. Thirty-three Grade 3 or 4 toxicities occurred in 22 of 260 (8 percent) patients overall during neoadjuvant therapy. Toxicity was more frequent in patients receiving chemoradiation (14/56; 25 percent) and long-course radiation (8/122; 7 percent) than in those receiving short-course radiation (0/82; 0 percent),P<0.0001. Perioperative complications occurred in 93 patients overall (36 percent). The postoperative mortality rate was 0.4 percent (1/260). There was no significant difference in the complication rate between patients treated with short-course radiation (26/82; 32 percent), long-course radiation (46/122; 36 percent), and chemoradiation (21/56; 38 percent). CONCLUSION: Neoadjuvant therapy for adenocarcinoma of the rectum is well tolerated and can produce substantial down-staging and a high curative resection rate. Chemoradiation can achieve high complete pathologic response rates, although toxicity during neoadjuvant therapy is greater than for radiation alone. Short-course radiation can achieve down-staging of both T stage and N stage.
A computational role for slow conductances: single-neuron models that measure duration

Humans effortlessly interpret speech and music, whose patterns can contain sound durations up to thousands of milliseconds. How nervous systems measure such long durations is unclear. We show here that model neurons containing physiological slow conductances are 'naturally' sensitive to duration, replicate known duration-sensitive neurons and can be 'tuned' to respond to a wide range of specific durations. In addition, these models reproduce several other properties of duration-sensitive neurons not selected for in model construction. These data, and the widespread presence of slow conductances in nervous systems, suggest that slow conductances might play a major role in duration measurement.
High-energy multileg electroweak processes and unitarity.

Because of the failure of the dilute-instanton-gas approximation (DIGA) at high energies, recent calculations of ({ital B}+{ital L})-violating processes in the standard model show blatant violations of unitarity, and suggest that these processes may be relatively unsuppressed at multiplicities {ital N}{similar to}{alpha}{sub {ital W}}{sup {minus}1}. We show how to cure the DIGA failure and restore the high-energy behavior necessary for consistency with unitarity in two ways: one in Minkowski space and the other in Euclidean space. In Euclidean space this is done by solving the classical field equations in the presence of space-time-dependent sources; we work out an explicit example. The same techniques allow us to investigate a similar failure of high-energy behavior in perturbation theory (({ital B}+{ital L})-conserving processes) as studied with the DIGA in the manner of Lipatov. An independent Minkowski-space analysis, also dealing with classical solutions in the presence of sources, confirms these results and shows that even with the right high-energy behavior, factors growing rapidly with {ital N} when {ital N}{ge}{alpha}{sub {ital W}}{sup {minus}1} still violate unitarity in the ({ital B}+{ital L})-conserving sector. Within the framework of a simple model which automatically restores unitarity, we investigate whether dispersion integrals relating high- and low-energy ({ital B}+{ital L})-violatingmore » processes can restrict the size of the high-energy {ital B}+{ital L} violation, and find that they cannot.« less
Distance relay performance as affected by capacitor voltage transformers

A 3-phase capacitor-voltage-transformer simulation is described which, when used in conjunction with a conventional artificial transmission line, allows complete relaying schemes to be tested. The accuracy of the simulation is confirmed by comparison of its response with that of a full-scale capacitor voltage transformer. Conjunctive distance-relay/capacitor-voltage-transformer tests are reported showing that transient errors degrade relay performance in speed and stability. Various methods for providing a more faithful voltage signal to supply the relay circuits are discussed.
Modeling study for optimization of skin dose for partial breast irradiation using Xoft Axxent electronic brachytherapy applicator.

Abstract Purpose Balloon brachytherapy with the MammoSite system (Hologic Inc., Bedford, MA) is a widely used approach for accelerated partial breast irradiation. Inherent to this approach, high skin doses can occur if the balloon to skin distance is small. This has been associated with late skin toxicity, particularly telangiectasia. The Xoft Axxent electronic brachytherapy balloon applicator (Xoft, Fremont, CA) is a novel device for accelerated partial breast irradiation. It is unique in that it uses an electronic 50-kV source. This source has a pronounced anisotropy with constriction of isodose distribution at the proximal end of the catheter. This anisotropy can be considered as an advantage to optimize skin dose when the cavity to skin distance is small. In this study, we simulated various balloon-insertion orientations to optimized skin surface dose. Methods Breast phantoms were constructed of tissue-equivalent material. Xoft Axxent balloon catheters were inserted at a distance of 6 mm from the surface. The catheter was placed at three different catheter to surface orientations: ( 1 ) perpendicular to the surface, ( 2 ) oblique to the surface (45°), and ( 3 ) parallel to the surface. Three-dimensional treatment planning was then performed using Nucletron's Plato planning system (Nucletron, Columbia, MD). Multiple dwell positions were used, and the dose was optimized to the target volume. The target volume was defined as volume from the balloon surface to 1-cm distance from the balloon surface or to the phantom surface (if less then 1 cm from the balloon surface). Target volume coverage was compared between plans using dose–volume histograms. Surface doses were compared using isodose line distribution and surface point doses. Plato planned surface doses were then verified by direct measurement using Landauer Dot InLight dosimeters (Landauer, Glenwood, IL). Results Excellent target coverage was obtained for all three catheter orientations with a D 95 of ≥95%. Surface dose was lowest for the perpendicular orientation with a calculated dose of 99%. The parallel orientation had the highest surface dose of 164%. The oblique orientation showed intermediate results with a surface dose of 117%. Measured surface doses were reproducible and correlated well with calculated values. Conclusion Optimized Xoft Axxent balloon catheter orientation using source anisotropy and multiple dwell positions can be used to minimize excessive skin dose and yet maintain optimal tumor cavity coverage when the cavity to skin distance is small. This has the potential to decrease skin late effects and improve cosmetic outcome. Further clinical study is warranted.
Try-in of the removable partial denture framework.

Summary This article provides the orderly sequence for fitting a removable partial denture framework to the mouth. Upon acceptance of the framework from the laboratory, the dentist must be aware that further adjusting or adaptation of the framework to the cast and to the mouth is often necessary.
Facilitating access point selection in IEEE 802.11 wireless networks

The performance experienced by wireless clients in IEEE 802.11 wireless networks heavily depends on the clients' ability to identify the Access Point (AP) that will offer the best service. The current AP affiliation mechanism implemented in most wireless clients is based on signal strength measurements received by the client from all the APs in its neighborhood. The client then affiliates with the AP from which it receives the strongest signal. It is well-known that such an algorithm can lead to sub-optimal performance, due to its ignorance of the load at different APs.In this work, we consider the problem of AP selection. We identify potential bandwidth as the metric based on which hosts should make affiliation decisions, and define it as the (MAC-layer) bandwidth that the client is likely to receive after affiliating with a particular AP. We further limit ourselves to the use of passive measurements that do not require an end-host to affiliate with the AP, thus allowing the end-host to simultaneously evaluate the potential bandwidth to multiple APs in range. This can also facilitate more informed roaming decisions. We propose a methodology for the estimation of potential upstream and downstream bandwidth between a client and an AP based on measurements of delay incurred by 802.11 Beacon frames from the AP. Preliminary experiments conducted in a controlled environment demonstrate that the proposed methodology looks promising, yielding fairly accurate results under varying conditions.
Dynamics and temperature dependence of etching processes of porous and barrier aluminum oxide layers

Abstract Electrochemical impedance spectroscopy (EIS) and ex situ spectroscopic ellipsometry (SE) are applied to study the growth and etching of porous and barrier oxide layers formed during anodization of 99.5% aluminum and 0.5% copper films. The equivalent circuit, which includes two parallel combinations each containing a constant phase element (CPE) and a resistor ( R ) connected in series with the cell uncompensated resistance, is suggested for description of the electrolyte/alumina/aluminum interface. While EIS is sensitive only to barrier oxide layer properties (the dielectric constant and thickness), SE provides information about both the porous and barrier oxide layers. SE is used to determine a thickness of the barrier oxide layer formed after 1-min anodization at a corresponding dc voltage. The EIS data combined with the ellipsometrically determined thickness of the barrier oxide layer allow for calculation of the dielectric constant of aluminum copper oxide. A previously established two-step anodization procedure is applied to grow ordered anodic aluminum oxide (AAO) arrays. EIS is shown to provide an accurate approach to monitor etching of the barrier oxide layer in a mixture of chromic and phosphoric acids. At a constant temperature, the thickness of the barrier oxide layer decreases almost linearly with time. The temperature dependence of the barrier oxide layer etching is studied for the first time and the activation energy of this process is found to be 42 kJ/mol. EIS is suggested to be a convenient method to determine the necessary duration of the etching process during application of the two-step anodization procedure. Non-destructive monitoring of growth and dissolution of alumina layers by means of EIS and SE is important to optimize conditions necessary for growth of ordered AAO arrays from aluminum films on solid supports.
Resolution of the light-dependent modulation system of pea chloroplasts

Abstract The mechanism of the light-dependent inactivation of glucose-6-phosphate dehydrogenase and the light-dependent activation of NADP + -malate dehydrogenase has been studied in partially purified extracts of pea ( Pisum sativum ) chloroplasts. Neither partially purified enzyme could be light modulated by washed thylakoids alone. However, a factor (mol. wt. 50 000) was present in the stroma which could, when added to purified enzyme and thylakoid membranes, reconstitute a light-dependent modulation of either glucose-6-phosphate dehydrogenase or NADP + -malate dehydrogenase. This factor, which we term protein-modulating factor, is distinct from ferredoxin-thioredoxin reductase and from thioredoxin, the factors involved in another scheme for light modulation. The scheme proposed here for light modulation involves electron transfer from Photosystem I to a membrane-bound light-effect mediator and then to the soluble protein modulating factor which modulates chloroplast enzyme activity, probably by reduction of a regulatory disulfide bond.
Optimal pest management by networked unmanned cropdusters in precision agriculture: A cyber-physical system approach

Abstract Unmanned Aerial Systems (UASs) are expected to see the largest application within the agricultural market. These versatile platforms have shown promise ushering in the next wave of precision agriculture. While remote sensing applications have been well documented and developed, there remains significant advances left to be made in improving the use of UASs for precision application of pesticides. Although the current mode of aerial spraying or application of pesticides within the U.S. is done using full-sized aircraft, future implementations for autonomous crop dusting are likely to utilize small unmanned aircraft systems (SUASs) due to their much lower cost and ease of use. However, these smaller platforms have limited payload capacities, thus the development of cooperative swarms of SUASs is necessary. In this paper, a swarm of cooperative SUASs are utilized within a cyber-physical system framework to optimize the use of pesticides with precision spraying. Through the use of Centroid Voronoi Tessellation, the swarm makes the most efficient use of pesticides to attack an invasive pathogen. Simulation results are presented to validate the performance of the proposed method.
Directional guidance of neurite outgrowth using substrates patterned with biomaterials

Abstract The use of geometrically simple networks formed by cultured neurons facilitates the electrophysiological study of biological computation. We used chemically patterned substrates for culturing SK-N-SH human neuroblastoma cells and embryonic rat hippocampal neurons to geometrically control their neurite outgrowth. On patterned substrates (parallel lines, 5–10 μm width), the neuroblastoma cells developed bipolar morphology with long neuritic processes (∼ 200 μm) in the presence of retinoic acid. Hippocampal neurons cultured on substrates of hexagonal patterns extended their neurites preferentially along the circumferences of the hexagons and formed geometrically well defined network structures.
Anamnesis, Sweat Electrolyte and Pulmonary Function Studies in Parents of Patients with Cystic Fibrosis of the Pancreas1

SUMMARY One hundred and two parents of children with cystic fibrosis and 52 control parents were studied with regard to physical examination of the chest, personal and family history, sweat electrolytes and pulmonary function tests. The physical examination of the chest was negative in all parents. When the C.F. parents were compared with the control group, no significant differences could be found in the personal and family histories of chronic cough, allergy, gastrointestinal disorders (ulcer and cholelithiasis) and diabetes. The concentration of sodium, chloride, and potassium in the sweat (produced by iontophoresis) was similar in the two groups of parents. The pulmonary function tests (vital capacity, timed vital capacity, peak expiratory flow rate, maximal breathing capacity, and nitrogen washout) showed no significant differences between the two groups of parents. This study provides no evidence that cystic fibrosis is inherited as a dominant disease. By the methods used no particular characteristics were found which could differentiate the heterozygote carrier of cystic fibrosis from the non-carrier.
Ethical considerations for residents.

To help residents understand the moral obligations they have undertaken by becoming doctors, the author presents an overview of the ethical landscape of medical practice. She begins by stating that doctors' primary obligation is to use the knowledge of science in working together with others for the good of their patients. This involves (1) relying on the scientific method (and thus eschewing nonscientific alternatives) and supporting or conducting scientific research; (2) embracing the cooperative model (i.e., when appropriate, working cooperatively with other physicians and other health care providers); and (3) working for the good of the patient to preserve life, cure disease, restore or preserve function, educate, and alleviate suffering. In order to fulfill this complex obligation physicians must be professionally competent, they must respect their colleagues and patients, and they must genuinely care about their patients' well-being. The author then discusses the moral complexity of common encounters in medical practice. She explains the ethical conflicts that underlie issues of paternalism, justice, the use of patients for teaching, and end-of-life care. Since new moral problems are introduced with new technology and since medicine is confronting an increasing demand for services in the face of shrinking resources, she maintains that, more than ever, physicians must be aware of the ethical dimensions of their work and be able to organize their understanding of the issues. To meet the complex and demanding commitments of medical practice and to successfully navigate the ethical challenges that they will encounter, physicians must mold themselves not only to be knowledge and skilled professionals but also to be respectful and compassionate human beings.
COMPASS: Computer oriented materials, processes, and apparatus selection system

Abstract Today's competitive manufacturing environment requires a shortened product development time. Although great emphasis has been placed on concurrent engineering, it is still a challenge for engineers to bridge the gap between design and manufacturing. This paper proposes a new approach to an emerging concept, Meta Planning, which brings manufacturing issues upstream by generating timely and appropriate feedback to design engineers. While a product or feature is being designed, all feasible downstream manufacturing processes can be compared. A meta planner can be integrated into existing CAD/CAPP/CAM systems to automate high-level process planning such that heterogeneous processes can be organized into a coherent plan. COMPASS (Computer Oriented Materials, Processes, and Apparatus Selection System), developed as a meta planner, has the basic framework to provide essential information regarding production cost, cycle time, and product quality for all of the candidate processes. It is a tool that helps design engineers identify potential manufacturing problems in the earlier stages of product development. Three different hole-making process models are implemented in COMPASS to illustrate the mechanism that analyzes and compares different manufacturing processes. Close interaction between design parameters and manufacturing performance for selected processes is demonstrated through a detailed case study involving a single feature.
The quantifier theory ofeven

is thought to express that Ted's sobriety was unexpected, or at least less expected than the sobriety of other individuals who are members of a relevant class. There is much disagreement about the precise nature of this class, its size, and how it is ordered. On Bennett's (1982) account, for example, even requires only the existence of at least one other individ ual who shares a relevant property. Fauconnier (1975) has offered the now popular theory that even sentences imply not just a related less surprising item but a scalarly ordered contrast class, with the object in focus of even at the end of such a scale. So, in example (1), Ted is presumably the surprising item at the end of a scale of individuals who can be rank-ordered according to their degree of expected drunkenness. Very recently, W. G. Lycan (1991) and Stephen Barker (1991) have argued (separately) that sentences with even make an implicit reference to a universal class. My aim in this paper is to examine a number of problems with respect to their versions of what I will call the universal quantifier theory of even. I will accommodate Lycan and Barker, retaining the idea that even implies quantification over a wider class, but I will produce evidence suggesting that even is ambiguous as between universal quantification and existential quantification.
Dispersion of the Index of Refraction Near the Absorption Edge of Semiconductors

A simple method is used to calculate the contribution of the rapid rise in optical absorption near the absorption edge of semiconductors to the index of refraction near the edge. Other contributions to the index are also estimated. The results give qualitative agreement with the results obtained for PbS by Riedl and Schoolar, and very good agreement with Marple's prism measurements of the index for GaAs. Some applications to injection lasers are discussed. The temperature and pressure dependence of the index of refraction near the absorption edge is estimated, and agrees well with experimental results for GaAs.
Free Vibration Analysis of an Inflated Toroidal Shell

Free vibration analysis of a free inflated torus of circular cross-section is presented. The shell theory of Sanders, including the effect of pressure, is used in formulating the governing equations. These partial differential equations are reduced to ordinary differential equations with variable coefficients using complete waves in the form of trigonometric functions in the longitudinal direction. The assumed mode shapes are divided into symmetric and antisymmetric groups, each given by a Fourier series in the meridional coordinate. The solutions (natural frequencies and mode shapes) are obtained using Galerkin's method and verified with published results. The natural frequencies are also obtained for a circular cylinder with shear diaphragm boundary condition as a special case of the toroidal shell. Finally, the effects of aspect ratio, pressure, and thickness on the natural frequencies of the inflated torus are studied.