cssi/SciSciGPT-SciSciNet huggingface dataset:
β-Carotene and/or vitamin E as modulators of alkylating agents in SCC-25 human squamous carcinoma cells

Dietary levels of β-carotene and vitamin E have been associated with cancer prevention and to a lesser extent, with therapeutic enhancement of cancer treatment. We report on the cytotoxicity of β-carotene, vitamin E, and the combination of β-carotene and vitamin E in human SCC-25 squamous carcinoma cells under various environmental conditions found in solid tumor masses. β-Carotene was selectively cytotoxic toward normally oxygenated cells and was generally more cytotoxic at normal pH than at acidic pH (6.45). Vitamin E was selectively cytotoxic toward normally oxygenated cells following 6 h exposure at normal pH and was generally equally cytotoxic toward normally oxygenated and hypoxic cells under the other conditions tested. β-Carotene was an effective modulator of cisplatin (CDDP) cytotoxicity toward SCC-25 cells, whereas vitamin E was not. Both β-carotene and vitamin E were effective modulators of melphalan cytotoxicity toward SCC-25 cells. Treatment of SCC-25 cells with β-carotene (70 μm, 2h) resultec in a reduction in superoxide dismutase activity, in glutathione-S-transferase activity, and in nonprotein sulfhydryl levels in the cells. Exposure to vitamin E or to a combination of β-carotene and vitamin E increased the glutathione-S-transferase activity in SCC-25 cells by 40%–45% over the control value. Treatment with β-carotene, vitamin E, or canthaxanthin reduced the incorporation of [3H]-thymidine into SCC-25 cells but not that into normal human karotinocytes. The most marked reduction in [3H]-thymidine incorporation into SCC-25 cells occurred following treatment with the combination of β-carotene and melphalan. We hope to continue to explore the mechanisms of this effect and to study these combinations in vivo.
Fiducial localization in C-arm based cone-beam CT

C-arm based Cone-Beam CT (CBCT) imaging enables the in-situ acquisition of three dimensional images. In the context of image-guided interventions this technology potentially reduces the complexity of a procedure's workflow. Instead of acquiring the preoperative volumetric images in a separate location and transferring the patient to the interventional suite, both imaging and intervention are carried out in the same location. A key component in image-guided interventions is image to patient registration. The most common registration approach, in clinical use, is based on fiducial markers placed on the patient's skin which are then localized in the volumetric image and in the interventional environment. When using C-arm CBCT this registration approach is challenging as in many cases the small size of the volumetric reconstruction cannot include both the skin fiducials and the organ of interest. In this paper we show that fiducial localization outside of the reconstructed volume is possible if the projection images from which the reconstruction was obtained are available. By replacing direct fiducial localization in the volumetric images with localization in the projection images we obtain the fiducial coordinates in the volume's coordinate system even when the fiducials are outside of the reconstructed region. The approach was evaluated using two anthropomorphic phantoms. When using the projection images all fiducials were localized, including those that were outside the reconstruction volume. The method's maximal localization error as evaluated using fiducials that could be directly localized in the CBCT reconstruction was 0.67 millimeters.
TRENDS AND METHODS IN LAND FORM GEOGRAPHY

ABSTRACT This paper reviews ideas of American geographers on geographic land form analysis and proposes a framework within which geographic land form studies can be identified and related to other land form studies. The following approaches are identified as geographic: 1) descriptive analysis of the present land form; 2) functional analysis of land form; 3) analytical studies of the covariation of individual land form elements; and 4) analytical studies of spatial variations in land form. Selected methods used in such studies are summarized and evaluated. Special emphasis is placed on descriptive methods.
On the validity and utility of discriminating among impulsivity-like traits.

The ability to make precise distinctions among related personality constructs helps clarify theory and increases the utility of clinical assessment. In three studies, the authors evaluated the validity of distinctions among four impulsivity-like traits: sensation seeking, lack of planning, lack of persistence, and urgency (acting rashly when distressed). Factor analyses indicated that lack of planning and lack of persistence are two distinct facets of one broader trait, whereas urgency and sensation seeking are both very modestly related to each other and to the planning/persistence measures. The authors developed interview assessments of each, and multitrait, multimethod matrix results indicated clear convergent and discriminant validity among the constructs. The distinctions among them were useful: The traits accounted for different aspects of risky behaviors. Sensation seeking appeared to relate to the frequency of engaging in risky behaviors, and urgency appeared to relate to problem levels of involve...
Modeling to determine dose dependence of drug and cell kinetic parameters.

Abstract In this work, we report on the use of a computer-based mathematical model which allows us to quantitate the in vivo effects of various chemotherapeutic agents on both malignant and normal cells. The usefulness of the model is shown by obtaining the dose response of the small intestinal crypt cells to Ara-C. The use of such an approach in determining optimal chemotherapeutic protocols for cancer treatment is discussed.
Rigid bronchoscopy and surgical resection for broncholithiasis and calcified mediastinal lymph nodes

Background Patients with calcified mediastinal lymph nodes who have hemoptysis or lithoptysis represent a challenging therapeutic dilemma. Methods We performed a retrospective review of a prospective clinic and operative database between January 1998 and December 2006. All patients had calcified mediastinal lymph nodes, symptoms or complications from these nodes, or both. Results There were 50 patients (23 men). Thirty-eight (76%) were symptomatic, which included hemoptysis in 11, persistent cough in 8, and recurrent pneumonia in 5, and all underwent rigid bronchoscopy. Thirty-four (89%) of the 38 symptomatic patients had stones eroding into the airway (broncholiths), and 2 had an airway esophageal fistula. The most common location of the broncholith was in the bronchus intermedius (n = 19). Endoscopic removal of the broncholith was performed in 29 patients and was successful in all. Elective thoracotomy with lymph node curettage, removal, or both was performed in 5 patients. These 5 patients had no significant morbidity and no operative mortality. Patients remained symptom free (median follow-up, 2.3 years; range, 8–42 months). Twelve asymptomatic patients with calcified lymph nodes were followed with serial computed tomographic scans and remain asymptomatic (median follow-up, 3.1 years). Conclusions Broncholiths that are not fixed to the airway can be safely removed with rigid and flexible bronchoscopic equipment. Thoracotomy with broncholithectomy is also safe and effective and is reserved for symptomatic lesions that cannot be removed bronchoscopically or for lesions that cause airway esophageal fistulas. Calcified nodes in asymptomatic patients are not an indication for intervention.
Comparison of polyethylene glycol and chromium-51 chloride as nonabsorbable stool markers in calcium balance studies

The day-to-day variations in stool calcium content during calcium balance studies are usually corrected for by adjusting for the recovery of an orally administered nonabsorbable stool marker. We describe here a simple method for making this correction using chromium-51 chloride hexahydrate (51Cr) in balance studies. This approach was developed because of difficulties encountered with the more widely used marker, polyethylene glycol (PEG). With one batch of PEG, the stool recovery was only 81% (whereas with 51Cr it was 95%). The reason for this poor recovery was contamination of the PEG 4000 with a high molecular weight species (10-15%, wt/wt). Because others have also reported low PEG recoveries and because we found that the chemical abnormality in the PEG was very difficult to detect, we believe that 51Cr is more reliable and should be the preferred stool marker for the calcium balance studies.
Schematic Models of Molecular Self-Organization

Molecular self-organization is central to the formation of numerous biological structures and the emulation of this process through the creation of synthetic counterparts offers great promise for nanofabrication. Our approach to understanding the principles governing this process is inspired by existing models and measurements on the self-organization of actin, tubulin and the ubiquitous icosahedral structures of viral capsids. We introduce a family of simple potentials that give rise to the self-organization of chain-like, random surface ('membrane'), tubular ('nanotube') and hollow icosahedral structures that are similar in many respects to their biological counterparts.
Secretory phospholipase A2-mediated progression of hepatotoxicity initiated by acetaminophen is exacerbated in the absence of hepatic COX-2

We have previously reported that among the other death proteins, hepatic secretory phospholipase A{sub 2} (sPLA{sub 2}) is a leading mediator of progression of liver injury initiated by CCl{sub 4} in rats. The aim of our present study was to test the hypothesis that increased hepatic sPLA{sub 2} released after acetaminophen (APAP) challenge mediates progression of liver injury in wild type (WT) and COX-2 knockout (KO) mice. COX-2 WT and KO mice were administered a normally non lethal dose (400 mg/kg) of acetaminophen. The COX-2 KO mice suffered 60% mortality compared to 100% survival of the WT mice, suggesting higher susceptibility of COX-2 KO mice to sPLA{sub 2}-mediated progression of acetaminophen hepatotoxicity. Liver injury was significantly higher at later time points in the KO mice compared to the WT mice indicating that the abatement of progression of injury requires the presence of COX-2. This difference in hepatotoxicity was not due to increased bioactivation of acetaminophen as indicated by unchanged cyp2E1 protein and covalently bound {sup 14}C-APAP in the livers of KO mice. Hepatic sPLA{sub 2} activity and plasma TNF-{alpha} were significantly higher after APAP administration in the KO mice. This was accompanied by a corresponding fall in hepatic PGE{sub 2}more » and lower compensatory liver regeneration and repair ({sup 3}H-thymidine incorporation) in the KO mice. These results suggest that hindered compensatory tissue repair and poor resolution of inflammation for want of beneficial prostaglandins render the liver very vulnerable to sPLA{sub 2}-mediated progression of liver injury. These findings are consistent with the destructive role of sPLA{sub 2} in the progression and expansion of tissue injury as a result of continued hydrolytic breakdown of plasma membrane phospholipids of perinecrotic hepatocytes unless mitigated by sufficient co-induction of COX-2.« less
What is a "Distributed" Data Processing System?

Words have only one purpose in a technical context–the transmission of information. When they fail to do that, they lead to confusion and misunderstanding. "Distributed data processing" and "distributed processing" are two phrases which illustrate that axiom. Like many other words in the lexicon of the computer professional, these have become cliches through over-use, losing much of their original meaning in the process. This paper is an attempt to reverse that trend.
ACP Journal Club. Review: New oral anticoagulants added to antiplatelets reduce CV events but increase bleeding after ACS.

Source Citation Oldgren J, Wallentin L, Alexander JH, et al. New oral anticoagulants in addition to single or dual antiplatelet therapy after an acute coronary syndrome: a systematic review and met...
Civic librarianship: Possible new role for depository libraries in the next century?

Abstract Profound changes have been taking place throughout the Federal Depository Library Program (FDLP) since passage of The Depository Library Act of 1962 (P.L. 85-579). This Act codified several critical perspectives regarding the role of libraries in a system of federal government information distribution; the responsibilities shared among FDLP's participating libraries (selective libraries and regionals), as well as the proper management and policy role for the Superintendent of Documents (and, by extension, the GPO). The foundation of these perspectives, obviously, depends on the relative limitations and advantages of printing technologies and paper-based distribution systems. Within this scheme, local “ownership” of collections housed in a wide variety of private and public institutions across the nation best meets the information needs of citizens. The enactment of the Government Printing Office Electronic Information Access Enhancement Act of 1993 (P.L. 103-40) shifts the FDLP's historic emphasis on local collection building and maintenance back to the Superintendent of Documents and the GPO. This article outlines several possible implications developing from this transformation.
Poems as Stories—Memories Illuminating the Lives of Experienced Early Childhood Teachers

In this essay, the author describes his curricular journey in creating a course on narrative inquiry and memoir for experienced early childhood educators. The author recounts the steps he took in selecting reading texts and activities for the course, and emphasizes the value of using poetry as a form of narrative for helping early childhood educators represent and understand key experiences and influences in their personal and professional lives. In presenting examples of the educators' original poems, the author points out the value of poetry to recount and illuminate small moments of experience, insight, and reflection for early childhood educators. Relevant background theory on the role of narrative and inquiry in early childhood and critical intersections between story and poetry are also provided. The author invites commentary todmeier@sfsu.edu; a copy of the syllabus on which this article is based is also available upon request.
RECURRENCE OF PRIMARY BILIARY CIRRHOSIS, AUTOIMMUNE CHOLANGITIS AND PRIMARY SCLEROSING CHOLANGITIS AFTER LIVER TRANSPLANTATION

Liver transplantation as a common therapeutic modality is still a relatively recent phenomenon; therefore, our understanding of the incidence and significance of disease recurrence after orthotopic liver transplantation (OLT) remains in evolution. Although identification in liver tissue of hepatitis B, delta antigens, and hepatitis C RNA 5 can be readily accomplished using immunohistochemical and polymerase chain reaction techniques, respectively, the recurrence of liver disease of putative autoimmune pathogenesis (primary biliary cirrhosis [PBC], autoimmune cholangitis, and primary sclerosing cholangitis [PSC]) is not as convincingly documented. Each of the autoimmune diseases can show overlap histological features with rejection, chronic viral hepatitis, drug reactions and, particularly in the case of PSC, ischemic cholangitis or other causes of large-duct biliary damage. Furthermore, because early recurrent disease is generally unaccompanied by symptoms and autoimmune serological markers often persist after OLT, it is difficult to detect recurrence clinically. Nonetheless, there is growing evidence that autoimmune biliary disease can recur in hepatic allografts.
Three-dimensional structure of human cyclin H, a positive regulator of the CDK-activating kinase.

Cyclin-dependent kinases (CDKs), which play a key role in cell cycle control, are activated by the CDK activating kinase (CAK), which activates cyclin-bound CDKs by phosphorylation at a specific threonine residue. Vertebrate CAK contains two key components: a kinase subunit with homology to its substrate CDKs and a regulatory subunit with homology to cyclins. We have determined the X-ray crystal structure of the regulatory subunit of CAK, cyclin H, at 2.6 A resolution. Cyclin H contains two α-helical core domains with a fold similar to that of cyclin A, a regulatory subunit of CAK substrate CDK2, and of TFIIB, a transcription factor. Outside of the core domains, the N- and C-terminal regions of the three structures are completely different. The conformational differences between cyclin H and A structures may reflect functional differences between the two cyclins.
SMARQ: Software-Managed Alias Register Queue for Dynamic Optimizations

Traditional alias analysis is expensive and ineffective for dynamic optimizations. In practice, dynamic optimization systems perform memory optimizations speculatively, and rely on hardware, such as alias registers, to detect memory aliases at runtime. Existing hardware alias detection schemes either cannot scale up to a large number of alias registers or may introduce false positives. Order-based alias detection overcomes the limitations. However, it brings considerable challenges as how software can efficiently manage the alias register queue and impose restrictions on optimizations. In this paper, we present SMARQ, a Software-Managed Alias Register Queue, which manages the alias register queue efficiently and supports more aggressive speculative optimizations. We conducted experiments with a dynamic optimization system on a VLIW processor that has 64 alias registers. The experiments on a suite of SPECFP2000 benchmarks show that SMARQ improves the overall performance by 39% as compared to the case without hardware alias detection. By scaling up to a large number (from 16 to 64) of alias registers, SMARQ improves performance by 10%. Compared to a technique with false positives (similar to Itanium), SMARQ improves performance by 13%. To reduce the chance of alias register overflow, the novel alias register allocation algorithm in SMARQ reduces the alias register working set by 74% as compared to a straightforward alias register allocation based on program order.
Mitochondrial Electron Transport Regulation of Nuclear Gene Expression (Studies with the Alternative Oxidase Gene of Tobacco)

We have isolated a cDNA representing the tobacco (Nicotiana tabacum L. cv Bright Yellow) nuclear gene Aox1, which encodes the alternative oxidase of plant mitochondria. The clone contains the complete coding region (1059 base pairs) of a precursor protein of 353 amino acids with a calculated molecular mass of 39.8 kD. A putative transit peptide contains common signals believed to be important for import and processing of mitochondrially localized proteins. We have studied changes in Aox1 gene expression in tobacco in response to changes in cytochrome pathway activity. Inhibition of the cytochrome pathway by antimycin A resulted in a rapid and dramatic accumulation of Aox1 mRNA, whereas the level of mRNAs encoding two proteins of the cytochrome pathway did not change appreciably. This was accompanied by a dramatic increase in alternative pathway capacity and engagement in whole cells. Respiration under these conditions was unaffected by the uncoupler p-trifluoromethoxycarbonylcyanide (FCCP). When inhibition of the cytochrome pathway was relieved, levels of Aox1 mRNA returned to control levels, alternative pathway capacity and engagement declined, and respiration could once again be stimulated by FCCP. The results show that a mechanism involving changes in Aox1 gene expression exists whereby the capacity of the alternative pathway can be adjusted in response to changes in the activity of the cytochrome pathway.
Structure concept in nasal tip surgery

When performing nasal tip surgery, a stable nasal base is critical in providing a good long-term outcome. Weakness in the nasal base can result in postoperative loss of nasal tip projection. Patients with a deficiency in the nasal base include those with inadequate tip projection, acute nasolabial angle, and dependency of the nasal tip. Maneuvers used to stabilize the nasal base include a sutured-in-place columellar strut, caudal extension graft, setting back and fixating the medial crura to an overly long caudal septum, or use of an extended columellar strut fixated to the periosteum about the nasal spine. Once the nasal base is stabilized, the lobule can be modified using domebinding sutures or a sutured-in-place tip graft. Use of these maneuvers can provide maximal tip projection with good tip contour. This article will discuss the principles behind the use of these techniques and discuss the nuances related to execution of the maneuvers.
Microbial Volatile Organic Compound Emission Rates and Exposure Model

This paper presents the results from a study that examined microbial volatile organic compound (MVOC) emissions from six fungi and one bacterial species ( Streptomyces spp.) commonly
Oxidant-induced intestinal barrier disruption and its prevention by growth factors in a human colonic cell line: role of the microtubule cytoskeleton.

Abstract Reactive oxygen metabolites (ROM) are increased in the inflamed mucosa of inflammatory bowel disease (IBD) and may contribute to loss of intestinal barrier function in this disorder. Growth factors (GF) are protective. But the mechanisms of disruption and protection remain elusive. In the present investigation, we hypothesized that the microtubules (a critical cytoskeletal element) play a key role in the molecular mechanism of intestinal barrier dysfunction induced by ROM and in GF-mediated protection. Utilizing monolayers of a human colonic cell line (Caco-2), we evaluated the effects of ROM (H 2 O 2 or HOCl), in the presence or absence of GF (epidermal growth factor [EGF]; transforming growth factor-α [TGF-α]), on intestinal barrier function, tubulin (microtubule structural protein), and microtubule stability. Monolayers were also processed for two highly sensitive western immunoblots: fractionated polymerized tubulin (S2; an index of stability); monomeric tubulin (S1; an index of disruption) to detect the oxidation and disassembly/assembly of tubulin. ROM exposure led to a significant increase in the oxidation of tubulin, decrease in the stable S2 polymerized tubulin, and increase in the unstable S1 monomeric tubulin. In concert, each ROM in a dose dependent manner damaged the microtubule cytoskeleton and disrupted barrier function. GF pretreatment not only increased the S2 stable tubulin and decreased tubulin oxidation but also, concomitantly, prevented the disruption of microtubules and loss of barrier function in monolayers exposed to ROM. Antibody against the GF-receptor and inhibitors of GF-receptor tyrosine kinase abolished GF protection, indicating the involvement of epidermal growth factor receptor (EGFR) signaling pathway. As predicted, colchicine, an inhibitor of microtubule assembly, caused barrier dysfunction and prevented GF protection whereas taxol, a microtubule-stabilizing agent, mimicked the protective effects of GF. Thus, organization and stability of the microtubule cytoskeleton appears to be critical to both oxidant-induced mucosal barrier dysfunction and protection of intestinal barrier mediated by GF. Therefore, microtubules may be useful targets for development of drugs for the treatment of IBD.
Characterization of blood-group-H-active ceramide tetrasaccharide from hog-stomach mucosa.

A fucose-containing ceramide tetrasaccharide exhibiting blood-group-H activity was isolated from a lipid extract of hog stomach mucosa by column fractionations on DEAE-cellulose and Florisil followed by purification on thin-layer plates. By partial acid hydrolysis, sequential degradation with specific glycosidases and methylation analysis, the structure of this glycolipid was identified as: Fucα1 , 2Galα1 3Galβ1 4Glc1 1Cer; where Fuc = fucose; Gal = glucose; Gal = glucose and Cer = ceramide.
Squamous lesions of the bladder

Abstract Squamous lesions of the bladder encompass a broad range of benign and malignant lesions. Many of the squamous lesions restricted to the urothelial surface are generally indolent, such as squamous metaplasia, squamous papilloma and condyloma acuminatum. However, some superficial lesions such as verrucous squamous hyperplasia and squamous cell carcinoma in situ may precede the development of invasive squamous cell carcinoma. Squamous lesions present within the wall of the bladder are often malignant and include classic squamous cell carcinoma and the verrucous squamous cell carcinoma and basaloid squamous cell carcinoma variants. One exception, however, is pseudoepitheliomatous (pseudocarcinomatous) hyperplasia, which is a benign mimicker of invasive squamous cell carcinoma. Our review summarizes the available data on clinical presentation, histopathologic features, differential diagnosis and ancillary tests of the squamous lesions of the bladder.
Specialized transduction of the biotin region of Escherichia coli by phage T1.

Phage T1 transduces Bio+ by special mechanism which leads to a higher efficiency of Bio+ transduction than other bacterial markers. Efficient Bio+ transduction depends on a site located between the galactose operon and the bacterial attachment site for phage λ. Evidence is presented which supports the hypothesis that the site is essential for efficient Bio+ transduction because at the site phage T1 initiates head filling in a polar (unidirectional) fashion leading to increased pickup of the Bio+ marker.
Contribution of Rating Scales to Intervention for Executive Dysfunction

Executive dysfunction is present in children, adolescents, and adults with a wide range of clinical conditions. A growing body of literature has demonstrated the usefulness of rating scales designed to gauge executive functioning in everyday life. In this article, we discuss evidence supporting the use of such rating scales to assess intervention outcome, how they may inform development of interventions, and how comparing rater perspectives can assess awareness of cognitive dysfunction. We provide an example of how an executive function rating scale helped define intervention targets and measured outcomes in a recently published real-world intervention for children with autism spectrum disorder. Rating scales of executive function provide valuable information with respect to treatment planning and assessment of intervention outcome.
Optimal thresholds of early response to atypical antipsychotics: Application of signal detection methods

Abstract Objective Identify the optimal magnitude of response to antipsychotic medication at various early time points that best predicts subsequent non-response at 8 weeks. Methods Data were pooled from 5 randomized, double-blind clinical trials of atypical antipsychotics in the treatment of schizophrenia and related disorders ( n = 1137 moderately-to-severely ill; n = 300 less than moderately ill). Signal detection methods (receiver-operating characteristic curves) were used to identify the optimal response threshold based on percent change from baseline on the PANSS total score at different early time points (Weeks 1–4) to predict subsequent ‘non-response’ at 8 weeks (i.e., not ‘minimally improved’, ‘much improved’ or ‘remitted’) while holding the false positive rate to a level of 30% or less. Analyses were implemented separately for patients with schizophrenia who differed on baseline illness severity. Results Using Area Under the Curve (AUC) ≥ 0.8 to define optimal discriminative ability at the earliest time point, the early response threshold in moderately-to-severely ill patients for predicting not ‘minimally improved’ was Conclusion Specific thresholds of response were identified at early time points for predicting subsequent non-response. Not attaining these early response thresholds may serve as important clinical markers of subsequent non-response to antipsychotic therapy.
Sinuses, staph, strep, patients, and families.

To the Editor.— In the “Clinical Practice Guideline: Management of Sinusitis,”1 it states that Streptococcus aureus is not a pathogen of concern. It seems likely that this was an error compounding Streptococcus pyogenes and Staphylococcus aureus, which both were left out of the list of pathogens of concern. It is surprising that these two bacteria are “not of concern.” Wald2 cites S pyogenes as a cause of 2% to 5% of sinus infections. And (since the guidelines state at the outset that “the pathogenesis and microbiology of acute otitis media and acute bacterial sinusitis are similar”) Wald’s group3 found 6% of otitis media isolates to be S aureus . Brook4 in one study finds 10 of 48 isolates of S aureus …
Bone marrow response to acute radiation injury in RFM-U mice after whole- and partial-body exposure to x-rays.

Abstract Whole-body exposure to a given dose of 250-kV X-rays (100 rads or 300 rads) induced greater cell depletion in the left femoral marrow of RFM/U mice than irradiation of the left femur alone. This is consistent with the concept that tissue damage produced by whole-body irradiation is due to a combination of direct and systematic injury. It is postulated that the systematic injury results from the suppression of protection afforded by the unirradiated tissues rather than from toxic agents emerging in the irradiated tissues. The loss of the nucleated cells (erythroblasts, lymphoid and myeloid precursor cells, mature myeloid cells) in the marrow of the irradiated left femur was paralleled by an increase in the number of marrow erythrocytes, so that the total count (nucleated cells plus erythrocytes) remained constant throughout the period of acute radiation injury. Both the nucleated cell response and the erythrocyte response were highly dose-dependent. Hence, the ratio of erythrocytes over nucleated cells, which can be estimated from a marrow biopsy variable and unpredictable size, may be useful as a biological dosimeter in estimating the radiation dose received by an individual.
The Effect of Asynchronous Inputs on Sequential Network Reliability

Synchronous sequential networks (SSN's) with high-frequency asynchronous inputs are subject to substantial failure rates due to the failure of input synchronizing networks. An apparent solution to this problem is to design asynchronous sequential networks (ASN's) to process the asynchronous inputs directly using the unrestricted input change technique of Unger. It is noted that this technique requires the use of inertial-delay elements and it is shown that inertial-delay elements can also be used to design reliable input synchronizers directly. Several common inertial-delay designs are examined. It is shown that none can be guaranteed reliable. An extensive dynamic analysis is required to prove the unreliability of one of these, an inertial delay which uses a Schmitt trigger. It is thus established that ASN's are subject to the same type of reliability problems as those recently exposed for synchronizers in synchronous networks. Furthermore, inertial delays are shown to be of central importance in that the development of a reliable inertial delay will solve both synchronous and asynchronous reliability problems.
Some Indonesian Epistolary Conventions

It has long been claimed that the facilitation of intercultural communication is one of the more valuable services applied anthropology can offer the layman. Yet in the course of their researches ethnographers often encounter—and put to use—customs, conventions, and rules of etiquette pertaining to communication, but neglect to publish descriptions of them because of their apparent triviality or lack of broader ethnological interest. As a result others are denied a valuable source of information that might enable them to avoid giving offense or otherwise improve communication across cultural boundaries. As an example of the kind of information that might be useful to the layman, I offer the following brief (and somewhat tentative) description of some nonobvious conventions pertaining to the writing of letters in Indonesia. The data presented here were collected from among several welleducated university students in Yogyakarta, Central Java. The informants represented Javanese, Sundanese (West Java), Madur...
Ecological Democracy: An Environmental Approach to Citizenship Education

Civic educators strive to develop the kinds of citizens who can identify and address the significant challenges of life in society. A case can be made that we have failed in this fundamental task. In spite of our efforts, contemporary societies seem ill-equipped to cope with the enormous social and environmental issues of our age. The problem is not merely with the broader population. Academics, too, have been unable or unwilling to assess the challenges we face. This essay explores the underlying nature of our contemporary situation and argues for a synthesis of citizenship education and ecological consciousness. The author suggests that civic education should be conducted within, rather than outside or beyond, a broader environmental context. Such an approach is imperative for the good of society and the health of the planet. The author argues that we can no longer afford anything less.
The response of fishes to physicochemical changes in the mangroves of northeast Florida Bay

Historically, large volumes of fresh water from the Everglades reached Florida Bay in the form of overland sheet flow. South Florida's extensive canal system has diverted fresh water from its historic course, resulting in shorter hydroperiods and higher salinities than would have occurred in an unaltered system. The mixing zone between the freshwater Everglades and euryhaline Florida Bay is primarily characterized as a dwarf red mangrove forest. The small, demersal fishes found in this habitat are an important food source for a variety of predators and are excellent bioindicators for both short-term and long-term perturbations in the system. I examine the effect of fluctuating water level, salinity, and temperature on this fish community in order to better understand the impact water diversion has had on the ecotone. Fish were collected at four sites within the ecotone over a t-yr period using a 9-m2 drop trap. Principal components analysis was used to generate 10 composite variables (PCs) from a temporal array of 59 physicochemical variables. These composite variables were used in regression analyses to evaluate spatial and temporal changes in the fish community. Regression analysis indicated fish density was significantly related to short-term and long-term changes in water level and with long-term temperature variation (r2=0.50). An ANOVA of density between sites supports the regression results, indicating that sites with longer hydroperiod had higher density than sites with shorter hydroperiod. The impact of changes in density on biomass was reflected by regression analysis, which indicated that increased water level and decreased variability in depth were correlated with higher biomass (r2=0.61). Biomass was also influenced by changes in the salinity regime, presumably through increases in individual fish body size or through a shift in the community toward heavier-bodied fish species. An ANOVA of biomass between sites indicates sites with longer freshwater periods had higher biomass than sites with shorer freshwater periods. The first two axes of a detrended correspondence analysis on community biomass explained 59.2% of the variance in the community and supported the hypothesis that salinity was a primary determinant of community structure. These results indicate historic changes in water deliver could have altered the mangrove fish community, thereby lowering prey availability for higher trophic levels.
Discriminability of change in signal flash-rates

Ssmmary.-Two experiments utilizing different psychophysical methods provided comparable estimates of the discriminability of differences in the rate of flashing of an alerting signal. In Exp. 1, a contingent-uncertainty analysis resulted in an estimated Weber ratio of < 0.07. In Exp. 2, the mechod of constant stimuli produced a mean Weber ratio of 0.06. Discriminability of flash rate differences was comparable for red and amber targets and for targets of -. 1" and 5" of visual angle. Lights flashing at rates of - 3 to 10 Hz may be used for a number of signalling or alerting purposes (McCormick & Sanders, 1982; Woodson & Conover, 1964). While such signals are recommended for use primarily to attract attention (Hutchingson, 1981), there may be times when it is advantageous to transmit information via a change in the flash rate of a signal light. For example, it has been shown that equipping vehicles with a rear-mounted lamp whose flash rate is positively correlated with the rate of vehicular deceleration can reduce the likelihood of rear-end collisions (Voevodsky, 1974). Coding of target parameters in terms of changes in flash-rate requires, of course, that the information be discriminable. While there is general agreement that absolute judgments are best achieved when only a small number of discrete flash-rates are employed (Hutchingson, 1981; Mortimer & Kupec, 1983; Tolin, 1984), there appears to be some disagreement in estimates of the minimum discriminable rate change. Two studies utilizing different psychophysical methods have given substantially different values. Mortimer and Kupec (1983) used the method of limits to obtain just-noticeable differences (JNDs) over the range of 1 to 9 Hz and reported that the median proportional change in frequency subjects could discriminate (Weber ratio) was 21%. Tolin (1984) required subjects to make judgments of whether the second of two sequentially presented lights flashed more rapidly, more slowly, or at the same rate as the first. Contingent uncertainties were computed and used indirectly to estimate the JND (Garner, 1962; Munson & Karlin, 1954). With a standard flash rate of 8 Hz, the estimated Weber ratio was 0.04. When
Simultaneous Estimation of Absolute and Relative Permeability by Automatic History Matching of Three-Phase Flow Production Data

This paper focuses on the simultaneous estimation of the absolute permeability field and relative permeability curves from three-phase flow production data. Irreducible water saturation, critical gas saturation, and residual oil saturations are assumed to be known. The two-phase relative permeability curves for an oil-gas system and the two-phase relative permeability curves for an oil-water system are represented by power law models. The three-phase oil relative permeability curve is calculated from the two sets of two-phase curves using Stone's Model II. The adjoint method is applied to three-phase flow problems to calculate the sensitivity of production data to the absolute permeability field and the parameters defining the relative permeability functions. Using the calculated sensitivity coefficients, absolute permeability, and relative permeability fields are estimated by automatic history matching of production data.
Comparison of the Single-Wavelength and Spectral-Reconstruction Methods for Determining the Solvation-Response Function

A comparison of the solvation/spectral-response functions obtained by two independent techniques, the single-wavelength and spectral-reconstruction methods, is reported. Determination of the best wavelengths for application of the linear-single-wavelength approximation for the solute coumarin 153 (C153) is achieved using radiative rate data and steady-state emission spectra in a series of 36 different solvents at room temperature. The optimal linear wavelength is found to be 555 nm. (This wavelength, which is on the red side of the spectrum, yields superior results when compared to the more traditional choice of 470--480 nm, on the blue side.) Response functions determined using both 560- and 470-nm observation wavelengths are compared to previously reported spectral-reconstruction results in 24 solvents. A comparison of the characteristic times indicates that the linear-single-wavelength method can be used to predict solvation times with an accuracy of roughly {+-}30--40% (1 standard deviation) using suitably scaled data collected at {approximately}560 nm. Application of a nonlinear version of the single-wavelength method does not provide increased accuracy.
Time-resolved electronic and optical properties of a thiolate-protected Au38 nanocluster

Density functional theory and density matrix theory are employed to investigate the time-dependent optical and electronic properties of an Au14 nanocluster protected by six cyclic thiolate ligands, Au4(SCH3)4. The Au14[Au4(SCH3)4]6 nanocluster, i.e. Au38(SCH3)24, is equivalent to a truncated-octahedral face-centred cubic Au38 core coated by a monolayer of 24 methylthiol molecules. The electronic and optical properties, such as density of states, linear absorption spectra, nonradiative nonadiabatic dissipative electronic dynamics and radiative emission spectra were calculated and compared for the core Au14 and thiolate-protected Au38(SCH3)24 nanocluster. The main observation from computed photoluminescence for both models is a mechanism of radiative emission. Specifically, a strong contribution to light emission intensity originates from intraband transitions inside the conduction band (CB) in addition to interband LUMO → HOMO transition (HOMO: highest occupied molecular orbital and LUMO: lowest unoccupied...
Differentiation of spinal and supraspinal opioid receptors by morphine tolerance

Mice treated for 72 hrs with morphine (subcutaneously implanted pellets) were tested with a variety of opioid receptor agonists to examine the development of tolerance and cross-tolerance to their analgesic action. The development of spinal and supraspinal tolerance following morphine treatment was evaluated by administering compounds systemically (sc), intrathecally (IT) and intracerebroventricularly (ICV). Following morphine treatment, tolerance to morphine analgesia was observed following IT, ICV and sc administration. Chronic morphine treatment also produced cross-tolerance to the analgesic effects of the selective delta opioid receptor agonist [D-Pen2, D-Pen5]enkephalin (DPDPE) following IT and ICV administration. However, morphine treatment selectively produced cross-tolerance to ICV [D-Ala2, NMePhe4, Gly-ol5]enkephalin (DAGO) (mu receptor agonist) analgesia, without altering IT DAGO analgesia. These results suggest that brain and spinal cord receptors mediating the effects of DAGO differ in terms of the development of cross-tolerance to morphine; and suggest that tolerance to systemic morphine may be due to changes in spinal delta and brain mu and delta receptor mechanisms.
Physicians' values and their career stage

Abstract Professional values of 241 practicing physicians were determined from factor analyzing their responses to 25 questionnaire items dealing with an ideal medical school in their vicinity. The seven factors (values)—(1) Academic, (2) Professional Separatism, (3) Support, (4) Social Welfare, (5) Research/Specialization, (6) Status/ Prestige, and (7) Convenience—were examined for their relationship to background characteristics (e.g., training) and practice (e.g., specialty). Few differences were found. However, when values were analyzed by age and career stage, significant fluctuations were found. Levinson's adult development theory was able to account for a sizeable portion of the observed variations. Practical and theoretical consequences are discussed in connection with physician stress at critical career stages.
A unique facility for surface microscopy

Abstract The Advanced Surface Microscopy Facility at the University of California at Davis is a unique collection of ultrahigh vacuum surface microscopy and analysis instruments, including a low energy electron microscope, a variable-temperature scanning tunneling microscope, and an X-ray photoelectron spectrometer. The system design has features for optimal sample transfer and handling among the primary instruments. The performance of the system is shown through LEEM images of clean Mo(100) and STM images of rutile TiO 2 .
On the bidirectional replication of the Bacillus subtilis chromosome.

We retract our previous conclusion that replication of the Bacillus subtilis chromosome is only partially bidirectional. Our conclusion was based on data obtained with mutants which we have now shown to have been misidentified. Moreover, identification of the replication terminus by virtue of its attachment to the cell membrane indicates that replication is completely bidirectional.
Gas Phase Rotamers of the Nucleobase 9-Methylguanine Enol and Its Monohydrate: Optical Spectroscopy and Quantum Mechanical Calculations

The present work reports a combined experimental and theoretical study of the 9-methylguanine (9MG) nucleobase and its monohydrate in the gas phase. Laser spectroscopy provides optical evidence for the presence of only one tautomer of 9MG, among the three forms expected from an energetic basis. Comparison with the calculated vibrational frequencies enables us to assign with confidence this form to the anti rotamer of the 9MG enol tautomer. The same approach allows us to conclude that the monomer conformation is retained in the monohydrate, with the water molecule bridging the OH proton donor and the N7 acceptor sites of 9MG. A complete comparison between all IR absorption data known for the enol tautomers of guanine and related compounds in the gas phase and the present calculations enables us to propose a consistent assignment for all of these enol tautomers in terms of rotamers. Finally, the fact that one does not observe either the most stable (and biologically relevant) keto form or the other enol rot...
Modeling Lanthanide Coordination Complexes. Comparison of Semiempirical and Classical Methods

A variety of approximate methods for efficient modeling of large lanthanide (Ln) complexes were studied. Attention was paid to ligand motifs prevalent in Ln coordination chemistry. Gadolinium was chosen given its central location in the Ln series and its importance in areas such as magnetic resonance imaging. A semiempirical approach based on a technique first described for europium was extended to gadolinium. Comparison with ab initio, molecular mechanics, and PM3 methods was performed for experimental and model complexes. Electrostatic models were found to be most reliable for cationic, large coordination number complexes with hard nitrogen and oxygen donorsan important subset of lanthanide complexes. When used for appropriate target complexes electrostatic models, particularly when used in conjunction with molecular mechanics, can be an effective and efficient technique for the study of large, experimentally relevant lanthanide coordination complexes.
A method for calibrating a hygrometer for refractory materials

Etalonnage d'un hygrometre pour la mesure de l'humidite des materiaux utilises et produits dans l'industrie des refractaires