cssi/SciSciGPT-SciSciNet huggingface dataset:
Inhibition of mammalian DNA polymerase-associated 3' to 5' exonuclease activity by 5'-monophosphates of 3'-azido-3'-deoxythymidine and 3'-amino-3'-deoxythymidine

Abstract 3′-Azido-3′-deoxythymidine 5′-monophosphate (AZT-MP) has been hypothesized by us to possibly affect 3′-azido-3′-deoxythymidine (AZT) excision from host cell DNA. In the present study, AZT-MP inhibited 3′ to 5′ exonuclease activity of calf thymus DNA polymerase δ at pharmacological relevant intracellular concentrations. Other 2′,3′-dideoxynucleoside-5′-monophosphate (ddN-MP) analogs, including 3′-amino-3′-deoxythymidine-5′-monophosphate (AMT-MP), were also assayed as potential inhibitors of 3′ to 5′ exonuclease activity. The monophosphate derivative of 3′-amino-3′-deoxythymidine (AMT), an in vivo toxic catabolite of AZT, was the most potent of the ddN-MP analogs tested, inhibiting this activity by more than 50% at 100 μM. These results suggest that inhibition of 3′ to 5′ exonuclease activities by AZT-MP and AMT-MP may increase steady-state levels of AZT in host DNA, accounting in part for the cell toxicity associated with this drug. The present study also raises the question of whether AZT-MP inhibition of this activity may lead to potential mutagenic effects due to inhibition of 3′ to 5′ exonuclease-mediated proofreading functions involved in DNA replication.
Editorial Comment: Is MVP an MVP in Ischemic Cerebral Events?

Support for mitral valve prolapse (MVP) as a source of cardiac embolism has undergone undulating cycles of enthusiasm over the past 25 years. When the association between stroke and MVP was mooted by the pioneering work of Barnett and colleagues,1 a new referral source opened for cardiologists. Then came the backlash. Many cases appeared to be incidental; studies did not identify an increased risk of cerebral embolism2; the condition was deemed to be a harmless variant, and common in the general population. Revised diagnostic criteria followed, and MVP was all but removed as a “most valuable player” in the team of cardiac abnormalities associated with cerebral embolism. The confounding associations did not help: MVP may be idiopathic and solitary with either familial or sporadic forms. Alternatively it may be secondary to connective tissue disorders or ischemic heart …
High-Performance Liquid Chromatographic Determination of Pilocarpine in Aqueous Humor: Derivatization by Quaternization of Methylimidazole Tertiary Amine Group

A derivatization procedure and a high-performance liquid chromatographic (HPLC) method of analysis for pilocarpine are described. The method is based on the quaternization of the 3′-tertiary amino group of the methylimidazole ring of pilocarpine with p-nitrobenzyl bromide. The HPLC system employs an RP-ODS column with a methanol–water mobile phase containing octanesulfonate as an ionpairing agent. The sensitivity of the method permits the analysis of pilocarpine in biological fluids such as aqueous humor. The method is selective for pilocarpine in the presence of isopilocarpine. Its applicability to the analysis of aromatic heterocyclic and alkyl tertiary amines is demonstrated.
Bessel's inequality in tensor space

Let A be an n-square complex matrix and define to be the n !-square matrix whose entries are , where σ and τ run lexicographically over Sn . If A is positive definite hermitian and χ is a unit n!-tuple then where c(A) is the largest of the numbers and the summation is over σ∊An . For n = 3, if A is not permutation similar to a direct sum and χ is a unit n!-tuple then ( χχ) = det(A) iff χ is a multiple of the alternating character. The relationships among recent results of Bapat and Sunder, Chollet, and Gregorac and Hentzel are also discussed.
SPATIAL MULTIPLIERS IN HEDONIC ANALYSIS: A COMMENT ON “SPATIAL HEDONIC MODELS OF AIRPORT NOISE, PROXIMITY, AND HOUSING PRICES”*

This note draws upon the spatial-hedonic analysis of Cohen and Coughlin to clarify the role of spatial multipliers in regression specification and benefits measurement, and to demonstrate the appropriate calculation of these benefits from dummy-variable coefficients in semi-logarithmic spatial-lag models.
Coming to Terms With the Public-Private Partnership A Grammar of Multiple Meanings

This essay critically examines the multiple meanings that the term, public-private (P-P) partnership, assumes in contemporary discussions. A brief deconstruction of this term not only clarifies these meanings, but also exposes to scrutiny their underlying premises and ideological commitments. Six distinct uses of the term are identified and linked to their respective meanings in neoconservative and neoliberal ideologies. Instead of focusing on partnership's conceptual definition, the term's strategic uses by political actors are attended to, consistent with the author's interest in partnership as a political symbol and policy tool. Accordingly, the claims of these actors about partnerships receive primary attention here. Their actual partnership practices and the distributional effects that partnering has on power and resources are left for others to consider.
A mechanism of action for the inhibition of black pigment dispersion in the fiddler crab, Uca pugilator, by naphthalene.

Abstract 1. The polycyclic aromatic hydrocarbon, naphthalene, inhibits the circadian dispersion of epidermal black pigment in the fiddler crab, Uca pugilator , by inhibiting the release of black pigment dispersing hormone. 2. Naphthalene caused no permanent neural damage in Uca pugilator . 3. Naphthalene did not cause a chemically-induced phase shift in the cireadian rhythmn of black pigment dispersion but reduced the daytime peak of that dispersion. Black pigment concentration, which occurs at night, was not affected by exposure to naphthalene. 4. Black pigment dispersing hormone in naphthalene-exposed crabs can be released by an injection of norepinephrine. 5. Given the points above, and previously published data, it is concluded that naphthalene inhibits circadian black pigment dispersion in Uca pugilator by inhibiting the release of the neurotransmitter, norepinephrine.
Correlation-based re-ranking for semantic concept detection

Semantic concept detection is among the most important and challenging topics in multimedia research. Its objective is to effectively identify high-level semantic concepts from low-level features for multimedia data analysis and management. In this paper, a novel re-ranking method is proposed based on correlation among concepts to automatically refine detection results and improve detection accuracy. Specifically, multiple correspondence analysis (MCA) is utilized to capture the relationship between a targeted concept and all other semantic concepts. Such relationship is then used as a transaction weight to refine detection ranking scores. To demonstrate its effectiveness in refining semantic concept detection, the proposed re-ranking method is applied to the detection scores of TRECVID 2011 benchmark data set, and its performance is compared with other state-of-the-art re-ranking approaches.
Studies on dihydroorotase activity in preparations from novikoff ascites hepatoma cells

Abstract Dihydroorotase activity was present in the supernatant fraction obtained after centrifugation at 100,000 g of a homogenate or sonicated preparation of Novikoff ascites hepatoma cells. The V max was independent of the pH of the assay, and the K m for carbamylaspartate was minimum (1.2 × 10 −3 M ) at the pH optimum (pH = 6.5). Enzymatic activity was rapidly destroyed at 50 °C. Protection of dihydroorotase from heat inactivation was afforded by the substrate, carbamylaspartate. The substrate protection against this heat inactivation could be titrated with respect to the time of addition of the substrate. The addition of sulfhydryl compounds, i.e., l -cysteine, β-mercaptoethanol, reduced glutathione, thioglycolic acid, effected a profound inhibition in enzymatic activity. An inhibition of 25–30% was obtained with approximately (6.7 × 10 −4 M reduced glutathione, 1.7 × 10 −3 M l -cysteine, 1.0 × 10 −3 M of β-mercaptoethanol, and −4 M of Na-thioglycolate. A comparable degree of inhibition of dihydroorotase activity, e.g., 50%, was obtained with 1.0 × 10 −3 M of either sodium dithionite, KCN, or Na 2 SO 3 , and 6.7 × 10 −5 M of Ag + or Hg ++ .
A Step-Down Protein Program for Commercial Pullets

Abstract Three experiments were conducted to evaluate the protein requirement of commercial egg production pullets from 8 to 20 weeks of age. Hyline W-36 pullets were used in Experiments 1 and 3, and Hisex White pullets were used in Experiment 2. They were fed a 20% protein diet for the first 8 weeks. In Experiment 1, a diet containing 14% protein did not result in body weight at 16 weeks equal to that obtained from feeding a diet containing 17% protein. In Experiments 2 and 3, body weights of pullets fed a diet containing 17% protein from 8 to 10 weeks followed by 1% protein reduction biweekly thereafter (12% from 18 to 20 weeks) was equal to that obtained by feeding 18% for the entire period. Performance in the laying house for four 28-day periods was equal for the two treatment groups. Feeding diets with suboptimal protein from 8 to either 12 or 14 weeks of age resulted in reduced body weight. However, when 14% protein was fed for the remainder of the growing period, body weight was restored.
Engineered MSC-Laden Cartilage Constructs are Sensitive to Inflammatory Cytokine-Mediated Degradation

Degeneration of cartilage resulting from trauma or disease processes is an increasingly prevalent problem in the aging population. Intrinsic repair of cartilage is limited and few methodologies exist, short of prosthetic replacement, for restoring damaged articular surfaces. These realities engender a need for new strategies for extrinsic repair. One strategy, tissue engineering, generates replacement cartilage composed of scaffolds and differentiated chondrocytes [1]. In addition to chondrocytes, recent work has demonstrated that mesenchymal stem cells (MSCs) isolated from bone marrow may be induced to take on a chondrocyte-like phenotype [2]. Tissue engineered constructs of either cell type can yield near-native properties (though those derived from MSCs are typically lower) [3]. While such constructs may be surgically implanted to replace areas denuded of cartilage, one factor to consider is that these defect sites exist in an already inflamed joint [4]. In addition, surgical interventions trigger further inflammatory responses, greatest in the area of intervention [5]. Recent literature has shown that pro-inflammatory cytokines, such as interleukin-1beta (IL-1β), instigate catabolic destruction not only of cartilage explants, but also of chondrocyte-based engineered cartilage constructs [6–9]. Still other studies have shown that un-differentiated MSCs themselves may exert an anti-inflammatory effect on their local environment [10–12]. Thus the current study examined the effect of varying doses of IL-1β exposure on both chondrocyte- and MSC-based engineered cartilage constructs to determine the relative sensitivity of neo-cartilage derived from each cell type to cytokine induced degradation.Copyright © 2007 by ASME
Soft drugs 4. 3-Spirothiazolidines of hydrocortisone and its derivatives

Abstract The previously unknown thiazolidines of some α,β-unsaturated 3-ketone steroids were prepared and characterized as 4,5-double-bond isomers. The thiazolidines readily reverted to their parent steroidal ketones, thus meeting the requirements for a prodrug. Most of the thiazolidines were more lipophilic than their parent steroids thereby imparting the desired change in the physical properties to the derivatives of the steroids. The thiazolidines of hydrocortisone 21-acetate (I and II) were more active than hydrocortisone or hydrocortisone 21-acetate, but the thiazolidines of the 17-esters were not. Thiazolidines I and II were less toxic systemically and this appears, at least in the case of I, to be due to the fact that less hydrocortisone was delivered through the skin from the application of thiazolidine I as from hydrocortisone 21-acetate. On the other hand, there was no appreciable disassociation of the increased activity of I and II from their ability to cause local atrophy.
An effect of glucose on bacteriophage synthesis in Salmonella typhimurium.

A MUTANT of Salmonella typhimurium has been obtained by Engelsberg (unpublished) which was characterized as ‘diauxie-resistant’ since, in contrast to the wild type, it could adapt itself to normally inducing substrates in the presence of glucose. The mutant was found by Engelsberg and Entner (unpublished) to contain three times as much glucose-6-phosphatase as the wild type. This enzyme difference suggests that the diauxie phenomenon can be explained by an extension of the hypothesis of Racker et al. 1 concerning the Crabtree effect, where it was suggested that glucose inhibits the utilization of endogenous materials by competing for the phosphate-nucleotide (adenylate) pool.
Role of salvage chemotherapy with topotecan and cisplatin in patients with paclitaxel- and platinum-resistant recurrent ovarian or primary peritoneal cancer: a phase II pilot study.

Background and Objectives We assessed the role of salvage chemotherapy with topotecan and cisplatin in patients with platinum- and paclitaxel-resistant advanced and recurrent ovarian or primary peritoneal cancer, based on the reported in vivo and in vitro synergism between these two drugs. Methods Twenty patients were entered in this phase II trial from November 1997 to November 1998. They received cisplatin at 50 mg/m2 on day 1 with topotecan at 0.6 mg/m2 from day 1 to 5 every 28 days. In 70% of patients (14/20), this combination represented at least a third line of therapy. Results A clinical response rate of 13.3% (two partial responses) was obtained in the 15 patients with evaluable disease. Sixty percent of patients (9/15) had stable disease and 26.7% (4/15) had progression. The median progression-free interval and survival were 4 months and 7 months, respectively. The 20 patients evaluable for toxicity received a mean of four chemotherapy cycles. Dose reductions were required in 45% of patients despite the administration of growth factors. The major dose-limiting toxicity was a 50% occurrence (10/20) of grade 4 thrombocytopenia and 30% (6/20) grade 4 neutropenia. There was one septic death. Conclusions These data suggest that combination therapy with topotecan and cisplatin has minimal activity in platinum- and paclitaxel-resistant advanced and recurrent ovarian or primary peritoneal cancer at the doses utilized in this trial. J. Surg. Oncol. 1999;72:162–166. © 1999 Wiley-Liss, Inc.
The respiratory metabolism of resting tsetse flies.

Abstract The respiratory rate of unfed tsetse flies at rest increases progressively with increasing temperature between 6 and 41°. The Q 10 of respiration exceeds 2·5 at temperatures below 30°, but at higher temperatures the proportionate increase in oxygen consumption becomes smaller. In fed flies the rate of respiration shows a marked increase as compared with the teneral level, and during most of the hunger cycle oxygen consumption is closely correlated with the amount of blood ingested. It is suggested that the increase in respiratory rate after feeding is a reflection of the metabolic transformation of blood into utilizable food reserve, and an estimate is obtained of the loss of energy involved in such transformation.
Use of Minicomputers in cTc Operation

This paper describes how minicomputers are applied to cTc operation, how they function in this application, and the needs they fulfill in today's technology.
Cyclical schedules vs. dynamic sequencing: Replenishment dynamics and inventory efficiency

Abstract This paper addresses the efficiency of fixed sequence (cyclical) scheduling systems, relative to that of dynamically sequenced, order point methods of production control. The criterion for comparison is the aggregate inventory required to achieve a target fill rate, taking into account the alternative replenishment dynamics arising under the respective systems. A simulation analysis demonstrates that cyclical scheduling may have smaller aggregate inventory requirement when the production process is highly utilized, and when this utilization is due to demand for a small number of items having large setup times.
Glycosylated Hemoglobin in Normal Subjects and Subjects with Maturity-onset Diabetes Evidence for a Saturable System in Man

Concentrations of glycosylated hemoglobin (GHb) are elevated in diabetes mellitus and are believed to reflect previous metabolic control. To better define possible determinants of GHb in man, we investigated the relationship between GHb and both fasting plasma glucose (FPG) and basal insulin (IRI) in 42 normal subjects and 29 patients with maturity-onset diabetes. Concentrations of GHb in diabetic subjects (12.7 ± 3.4, x ± S.D., per cent total hemoglobin) were significantly higher than in normal subjects (8.2 ± 1.2, p
Intraoperative imaging and fluorescence image guidance in oncologic surgery using a wearable fluorescence goggle system

We have developed a wearable, fluorescence goggle based system for intraoperative imaging of tumors and image guidance in oncologic surgery. Our system can detect fluorescence from cancer selective near infra-red (NIR) contrast agent, facilitating intraoperative visualization of surgical margins and tumors otherwise not apparent to the surgeon. The fluorescence information is displayed directly to the head mounted display (HMD) of the surgeon in real time, allowing unhindered surgical procedure under image guidance. This system has the potential of improving surgical outcomes in oncologic surgery and reduce the chances of cancer recurrence.
The Amerindians in Guyana, 1803-1873: A Documentary History

These selected documents reveal the reaction and responses of the Amerindians to European values.
Theories of Gender Stratification: Assumptions, Evidence, and “Agency” and “Equity” Implications

Gender stratification theories are reviewed in light of their causal assumptions, empirical evidence, and “agency” and “equity” implications. Agency involves the relative capacity of the individual to influence occupational outcomes; equity pertains to the perceived fairness of occupational rewards. It is concluded that the empirical support for the structural functionalist, structural barriers, cognitive, normative barriers, and normative alternative theories of gender stratification is either contradictory, equivocal, or limited. Further compounding the mixed empirical record is that the method used by many proponents of the structural barriers approach to measure sex discrimination is based on a logical fallacy that confuses outcome with process. Finally, the theories make quite divergent assumptions concerning agency and equity. These differences lead to contradictory conclusions about the degree that individuals, and particularly women, can control their occupational destiny, the possibility of incre...
Catalysis of accurate poly(C)-directed synthesis of 3'-5'-linked oligoguanylates by Zn2+.

Abstract Zn 2+ is an efficient catalyst for the oligomerization of guanosine 5′-phosphorimidazolide on a polycytidylic acid template. Up to 75% of the input ImpG † is converted to oligomers with a mean chain length up to 10. Material longer than (pG) 30 can be detected. The oligomeric products are predominantly 3′-5′-linked. If poly(C) is incubated with ImpG and an equimolar quantity of the 5′-phosphorimidazolides of adenosine, uridine or cytidine, in the presence of Zn 2+ , ImpG is incorporated at least 200 times more efficiently than “incorrect” nucleotides.
The Biological Consequences of the Mississippian Expansion into the Western Great Lakes Region: A Study of Prehistoric Culture Contact

Analysis of the impact of complex societies on small societies has rarely been addressed in the archeological record. This is done here in a case study from the prehistoric midwest with documentation of contacts between Middle Mississippians and indigenous peoples of the western Great Lakes region. Human skeletal remains have been analyzed in order to demonstrate the introduction of new subsistence practices and diseases into the upper midwest from the Mississippian core. Skeletal remains have also been analyzed for evidence of inter-group conflict. These data are synthesized by modeling the demographic impact on populations of the upper midwest.
Characteristics of cultured human renal cortical epithelia

Abstract Nine human kidney epithelial cell lines, isolated from small biopsied material and from whole kidney, were propagated in both a hormonally defined medium and a medium supplemented with serum. At confluency, hemicysts or domes, typical of cultured epithelial cells, were formed by these cells. Monolayers had junctional complexes between cells and the presence of numerous microvilli on the cell surface. Parathyroid hormone markedly stimulated these cells to produce cyclic AMP. They also contained high levels of γ-glutamyltranspeptidase, leucine aminopeptidase, and maltase, enzymes that are associated with the brush-border membrane of the proximal tubule. The cultured cells demonstrated the ability to transport amino acids and α-methylglucoside, a substrate actively transported only by the proximal tubule in the kidney. Based on these findings, the cultured cells reflected a number of characteristics associated with the proximal tubule. These renal epithelial cell lines may provide a useful model for studying various aspects of human renal physiology and biochemistry.
Reconstructing the mechanical properties of coronary arteries from displacements measured with a synthetic aperture ultrasound imaging system

In this paper, we explore the feasibility of reconstructing the mechanical properties of vascular tissues from axial and lateral displacement measurements from Synthetic Aperture (SA) ultrasound images. Modulus values were reconstructed with a soft priors technique. Studies were performed on simulated and experimental vessel phantoms to evaluate the quality of elastograms completed from axial displacements only, relative to those computed from axial and lateral displacements. Results demonstrated that modulus elastograms computed using both components were more accurate than those computed using one component of displacement.
Molecular cloning and expression of rat kallistatin gene

We have previously purified and cloned human kallistatin and rat kallikrein-binding protein (RKBP), which are tissue kallikrein inhibitors belonging to the serine proteinase inhibitor superfamily. In this study, we have cloned and sequenced the gene encoding rat kallistatin with Phe-Phe-Ser-Ala-Gln at positions P2-P3', which is identical to the reactive center of human kallistatin. Rat kallistatin is highly similar to human kallistatin, sharing 68% and 57% sequence identity at the cDNA and the amino acid levels. The rat kallistatin gene exists in a single copy and is located on chromosome 6. An SphI RFLP is found between SHR and WKY rats at or near the rat kallistatin gene locus. Two amino acid polymorphisms of the rat kallistatin gene between these two strains were found by sequence analysis. A candidate promoter in the 5'-flanking region (109 bp) of the rat kallistatin gene has been identified by reporter assays. The expression of rat kallistatin in the liver is growth-dependent and down-regulated during acute phase inflammation. Recombinant rat kallistatin produced in E. coli is able to bind to tissue kallikrein, and the interaction is inhibited by heparin. These characteristics define rat kallistatin as the counterpart of human kallistatin.
Lattice Vibrations and Thermal Properties of Stoichiometric KYb(WO4)2 Crystal

Single crystal KYb(WO4)2 (KYbW) has been grown by the top-seeded solution growth (TSSG) method. Polarized Raman and infrared spectra have been recorded at room temperature. The lattice vibration modes were calculated, and the strongest peaks appear at 760 and 908 cm−1 with a line-width ΔωR of 14.2 and 10 cm−1, corresponding to relaxation times of 0.747 and 1.061 ps, respectively. This makes KYbW attractive for stimulated Raman scattering (SRS) applications and for use in the picosecond regime. Differential thermal analysis and thermal gravimetric analysis curves, high-temperature X-ray diffraction patterns, specific heat, thermal expansion and thermal conductivity have been studied. The thermal expansion anisotropy of KYbW is weaker than that of KGd(WO4)2 (KGW), but stronger than that of KLu(WO4)2 (KLuW). The thermal diffusivity along the c-axis is large (λc > λa > λb). The results are consistent with the anisotropic structure of crystalline KYbW.
Phosphorylation of the androgen receptor by a nuclear cAMP-independent protein kinase.

Abstract The androgen receptor was purified from rat ventral prostate. The purified receptor migrated as a single band of mol. wt. 87000 on SDS-polyacrylamide gels, had a K d for R-1881 (17 β-hydroxy-17α-methyl-estra-4,9,11-trien-3-one) binding as 6 nM, and sedimentation coefficient of 4.5 S. Phosphorylation of the purified receptor was studied by incubating it with [γ- 32 P]ATP in the presence of several purified protein kinases including cAMP-dependent protein kinase, and four cAMP-independent protein kinases (which were active towards substrates such as phosvitin and casein). Phosphorylation of the 87000 mol. wt. androgen receptor protein occurred only in the presence of a nuclear cAMP-independent protein kinase (of the N2 type). No auto-phosphorylation of the receptor was detected. The results indicate that the androgen receptor is a phosphoprotein. Further, phosphorylation of the androgen receptor by only a specific nuclear cAMP-independent protein kinase may be important in determining the dynamics of its function.
Is air medical scene response for illness appropriate

The purpose of this study was to determine the appropriateness of air medical scene response for illness. The study consisted of a retrospective chart review of a two-helicopter urban air medical transport program with a transport volume of 1,700 flights annually. During the study period, January 1988 through March 1990, 68 patients were transported by helicopter from scene of illness to a tertiary care facility. In cases in which patients could be managed appropriately locally, air transport was deemed unnecessary. Of the 68 patients with illness, 40 were males and 28 were females; the average age was 39.2 years (from a range of 0 to 93). The average transport time was 46.3 minutes. Dispatch diagnoses were cardiac arrest (20), seizure (14), myocardial infarction (8), overdose (6), stroke (5), labor (4), respiratory distress (3) and miscellaneous (8). The discharge (final) diagnosis was different from dispatch diagnoses in 10 patients (14.7%). Fifty-four patients (79.4%) required no tertiary care, and 30 of them were discharged from the emergency department or were pronounced dead there or at the scene. The results of the study indicate air medical response to scene of illness did not appear justified in this study. Transport should be local, by ground, with subsequent tertiary care being arranged as needed. Further prospective study is warranted.
Elevated midtrimester α-fetoprotein and delivery markers of inflammation in a preterm population

Objective: Determine whether elevated second trimester maternal serum α-fetoprotein (AFP) is associated with clinical and histopathologic markers of inflammation at preterm delivery. Methods: 105 women <32 weeks’ gestation were included. AFP levels were dichotomized at 2.0 multiples of the median (MoM). Rates of neonatal morbidities, clinical chorioamnionitis, cord blood IL-6 level, and placental inflammatory findings were compared. Results: Thirteen (12.4%) had elevated AFP. Fewer women with AFP ≥2 MoM had histologic placental or membrane rupture site inflammation, funisitis, or placental culture positive for Mycoplasma and Ureaplasma species, compared to those with normal AFP. Neonatal death was increased in the elevated AFP group (23.1% vs. 2.27%, RR 10.6). Elevated AFP was associated with a nonsignificant increase in indicated birth (54% vs. 35%; p = 0.225). Virtually all inflammatory findings were confined to the spontaneous delivery group. Conclusion: Elevated midtrimester AFP conveyed significant r...
Residual heat deposition in dental enamel during IR laser ablation at 2.79, 2.94, 9.6, and 10.6 μm

Background and Objective The principal factor limiting the rate of laser ablation of dental hard tissue is the risk of excessive heat accumulation in the tooth. Excessive heat deposition or accumulation may result in unacceptable damage to the pulp. The objective of this study was to measure the residual heat deposition during the laser ablation of dental enamel at those IR laser wavelengths well suited for the removal of dental caries. Optimal laser ablation systems minimize the residual heat deposition in the tooth by efficiently transferring the deposited laser energy to kinetic and internal energy of ejected tissue components. Study Design/Materials and Methods The residual heat deposition in dental enamel was measured at laser wavelengths of 2.79, 2.94, 9.6, and 10.6 μm and pulse widths of 150 nsec −150 μsec using bovine block “calorimeters.” Water droplets were applied to the surface before ablation with 150 μsec Er:YAG laser pulses to determine the influence of an optically thick water layer on reducing heat deposition. Results The residual heat was at a minimum for fluences well above the ablation threshold where measured values ranged from 25–70% depending on pulse duration and wavelength for the systems investigated. The lowest values of the residual heat were measured for short (< 20 μs) CO2 laser pulses at 9.6 μm and for Q-switched erbium laser pulses at 2.79 and 2.94 μm. Droplets of water applied to the surface before ablation significantly reduced the residual heat deposition during ablation with 150 μsec Er:YAG laser pulses. Conclusions Residual heat deposition can be markedly reduced by using CO2 laser pulses of less than 20 μsec duration and shorter Q-switched Er:YAG and Er:YSGG laser pulses for enamel ablation. Lasers Surg. Med. 29:221–229, 2001. © 2001 Wiley-Liss, Inc.
Interaction of Sucrose Esters with Skim Milk Proteins as Characterized by Affinity Chromatography

Abstract The interaction of sucrose ester, P-1670 (70% pure palmitic acid monoester), with milk proteins was examined by affinity chromatography. The ester was covalently bound to 3-aminopropyl controlled-pore glass by periodate oxidation of the carbohydrate to aldehyde, formation of the Schiff base, followed by reduction to secondary amine. In phosphate buffer, pH 7, α -LA did not appear to interact with sucrose ester, but β -LG exhibited binding. However, casein micelles were very tightly bound, and caseins could only be eluted following addition of urea. On application of skim milk, the strengths of the interactions, as reflected by their elution volumes, decreased in the order: α s -CN, κ -CN, β -CN, β -LG, and α -LA. Micelles dissociate after addition of urea, allowing individual caseins to interact with sucrose ester moieties in the presence of increasing urea concentrations. Apparent dissociation constant was 2.04 μM for the binary complex using solutions of pure β -LG in agreement with the value for soluble complexes measured by other methods. Hydrophobic interaction appears to be the major force stabilizing complex formation, even though the affinities of the individual caseins do not follow the order of their overall hydrophobicities. Tight binding of micelles to the immobilized sucrose esters suggests that the alkyl chains are able to insert into hydrophobic regions of surface submicelles.
REGIONAL DIFFERENCES IN SKIN GLAND DIFFERENTIATION IN RANA PIPIENS.

The paper deals with the study of development of skin glands in normal and in thyroxine treated Rana pipiens larvae. The development of skin glands in various regions is found to be sequential. The glands also undergo development at different rates in different regions. At high thyroxine concentrations the mucous glands were found to differentiate faster than serous glands. Hormone treatment, besides precocious skin maturation brings about temporal separation of otherwise simultaneous events. The findings emphasize the intrinsic, qualitative differences of cells of the skin system.
Molecular basis of an adult form of β-hexosaminidase B deficiency with motor neuron disease

A patient (KL) with progressive motor neuron disease associated with partial Hex A (αβ) and no Hex B (ββ) activity, synthesized β-chains which only associated with α-chains. To identify the molecular basis of this inability of β-chains to self associate, RNA from cultured fibroblasts was reverse transcribed, the cDNA encoding the β-chain amplified by polymerase chain reaction, subcloned, and sequenced to reveal two types of single missense mutation. The first mutation, (Type I) 619 A ➡ G, was paternally inherited and converted a 207 lle ➡ Val in a highly conserved region believed to be associated with catalytic activity and activator protein binding. Biochemical evidence for impaired activator protein binding was obtained by purifying Hex A from KL urine and demonstrating a greater than 50% reduction of in vitro G M2 hydrolysis compared to normal urinary Hex A. In other cDNA species (Type II), a maternally inherited 1367 A ➡ C mutation converted 456 Tyr ➡ Ser in another highly conserved region of the β-chain and we propose that this mutation leads to the inability of the β-chains to self associate and thus reach maturity. These same cDNA species contained a second 362 A ➡ G mutation which converted 121 Lys ➡ Arg, but is apparently a polymorphism since it also occurs in some normal subjects. We propose that the patient is a compound heterozygote in which a combination of no self-association of the mutant β-chains and impaired activator protein binding to α-β (mutant) (Hex A) required for G M2 hydrolysis result in total β-Hex B deficiency and slow accumulation of G M2 ganglioside, primarily in motor neurons.
Steady‐state currents in p‐n junction filaments or grains in case of large surface recombination velocities at lateral surfaces

Recently it has been pointed out that the saturation current of a semiconductor filament which constitutes part of a p-n junction diverges when the surface recombination velocity at the faces become infinitely large. Here it is pointed out that this is to be expected on physical grounds since, whenever the carrier concentration is kept off equilibrium by an outside agent, and at the same time recombination lifetimes in the bulk or in surface layers tend to zero, concentration gradients tend to infinity. As also previously noted, the situation can be remedied by using realistic (finite) surface recombination velocities in model calculations. However, this procedure leads to mathematical complexities which have been circumvented recently by the introduction of a heuristic approach. It is the aim of this paper to assess the validity of the heuristic approach by means of detailed and exact calculations.
Tests of microstrip dispersion formulas

A set of published formulas for the frequency dependence of the microstrip effective relative dielectric constant epsilon /sub re/(f) is tested relative to an assemblage of measured data values for this quantity chosen from the literature. The RMS deviation of the predicted data obtained from the measured values ranged from 2.3% to 4.1% of the seven formulas for epsilon /sub re/(f) tested. A formula due to M. Kirschning and R.H. Jansen (see Electron. Lett., vol.18, p.272-73, 1982) showed the lowest average deviation from measured values, although the differences between the predictions of their formula and others tested are of the order of the error limits of the comparison process. It is concluded that the results indicate the suitability of relatively simple analytical expressions for the computation for microstrip dispersion. >
Design of On-Target FAAH Inhibitors

In this issue of Chemistry & Biology, Alexander and Cravatt [1] propose a model for the binding of carbamate inhibitors to fatty acid amide hydrolase (FAAH), the enzyme that breaks down signaling lipids. Using competitive activity-based protein profiling and click chemistry, they designed potent and selective FAAH inhibitors and characterized their off-target reactions.
Differentiation of massive pericardial effusion from cardiac dilatation using I131 albumin

Abstract 1. 1. An isotope technique for the measurement of intracardiac blood volume has been used to detect massive pericardial effusion. 2. 2. An outstanding feature of this procedure is its simple and innocuous nature. 3. 3. In 5 patients with pericardial effusion and normal hearts the cardiac shadows were enlarged whereas the intracardiac blood volumes were normal. 4. 4. The results indicate that this is a sound approach to the clinical diagnosis of pericardial effusion.
Completeness of zero curve tracing for analytic functions

Abstract Empirical data for the polynomial confirm the efficiency of exploring function structure as a means of isolating the zeros of a scalar analytic function defined on a disk (Klip, 1985). In exceptional cases the tracing is not complete which means that certain arcs may not have been traced. A mathematical basis for the algorithm which investigates and restores completeness, the so-called completeness algorithm, is presented. The main theorem is that completeness of the tracing, as verified at the isolated zeros, is sufficient for completeness of the tracing. Its proof evolves along various lemmas, one of which provides a new condition for the location of the critical points. The paper concludes with a brief description of the completeness algorithm.
A dash of protons: A theoretical study on the hydrolysis mechanism of 1-substituted silatranes and their protonated analogs

Abstract A b initio calculations were carried out to study the hydrolysis mechanism of 1-substituted silatranes in the presence of an acid (acid-catalyzed) and an additional water (water-assisted). Compared with the neutral hydrolysis mechanism involving one water, use of an acid catalyst reduces the barrier associated with the rate-limiting step by ≈14 kcal/mol. A modest decrease of ≈5 kcal/mol is predicted when an additional water molecule is added to the neutral hydrolysis mechanism involving one water. The combination of an acid catalyst and an additional water molecule reduces the barrier by ≈27 kcal/mol. Bond order analysis suggests ring cleavage involving the bond breaking of a siloxane and silanol group during the neutral and acid-catalyzed hydrolysis of 1-substituted silatranes, respectively. Solvent effects, represented by the PCM continuum model, do not qualitatively alter computational gas-phase results.
Interspecies and gender differences in multifocal electroretinograms of cynomolgus and rhesus macaques.

The purpose of this study is to ascertain whether inherent differences exist in the retinal function of two macaque species that are commonly used in experimental glaucoma investigations. We quantified and compared multifocal electroretinograms (mfERGs) from ocularly normal cynomolgus (n = 6) and rhesus (n = 8) monkeys. The stimulus array consisted of 103 equal-sized hexagonal elements, which subtended ±44° about the central visual axis. Mean luminance of the display was 100 cd/m2. The first-order kernel (K1) and second-order (first slice) kernel (K2) of the mfERG were averaged into 4 rings radiating from the foveal element, and represented the central 56° of visual field. Fifteen and 30-element segments were used for K1 and K2 quadrant and hemiretinal response determinations, respectively. Response measures for the rings, quadrants, and hemiretinae included K1 amplitude and implicit time, and K1 and K2 oscillatory potentials (OPs) and response amplitude root mean square (RMS). Species, gender, and retinotopic differences were assessed with repeated measures analysis of variance (split plot design). K1 amplitudes of the N1 waves, K1 and K2 OPs and K2 amplitude RMS for the ring, quadrant, and hemiretinal mfERG waveforms were larger in rhesus than in cynomolgus monkeys. Rhesus males (as compared to rhesus females) and cynomolgus females (as compared to cynomolgus males) exhibited larger amplitudes and less delayed implicit times in the central retina. These results demonstrate that species-specific differences in retinal function are evident in cynomolgus and rhesus monkeys. There also were gender-associated differences that varied across species. Thus, investigators should exercise caution when data from species or gender are combined.
Centralized optical backplane with energy equalized fan-outs for board-to-board interconnections

We describe a new method for broadcasting signals in an optical backplane bus system based on guided-wave interconnects. By introducing a distributor (an active coupler) in the center board, which consists of a receiver, a doubly multiplexed hologram, and a transmitter, all signals coming from boards are collected in a receiver in the distributor and then are rebroadcasted from transmitter in the distributor to all boards. This method shows a variety of advantages such as equalized fan-out powers, increased the interconnect distance, reduced number of holograms, and easier system assembly. We show the design concepts for a centralized optical backplane, and resulting experimental performance advantages over previously- developed free-space and guided-wave optical backplane bus systems.
Living donor liver transplantation: histological abnormalities found on liver biopsies of apparently healthy potential donors.

Objective: With the continued shortage of deceased donor grafts, living donor liver transplantation has become an option for adult liver transplant candidates. In the non-transplant setting, liver biopsy is typically carried out to evaluate clinical or biochemical hepatic dysfunction. In living donor liver transplantation, assessment of histological abnormalities that are undetectable by serological, biochemical and radiological methods might play an important role in donor and recipient outcome. Methods: Seventy consecutive liver biopsies carried out as part of our evaluation of potential donor candidates for adult-to-adult or adult-to-child living donor liver transplants were analyzed. Results: Of the 70 potential donor candidates who underwent liver biopsy for evaluation for living donor liver transplantation, 67% had an unexpected abnormality, of which steatosis was the most common abnormality (38.5%). A variety of other histopathological abnormalities were found including granulomas of unknown etiology (7%), chronic hepatitis (6%) and a microabscess. None of the histological abnormalities had been suspected despite extensive clinical, serological or radiological investigation. Conclusions: Among the 70 potential donor candidates for living donor liver transplantation, 34% had unremarkable liver biopsies. The most common abnormality was steatosis (38.5%). These findings suggest that all potential candidates for living donor liver transplants should undergo screening liver biopsies. The precise significance of these changes remains to be determined, including which of these changes are contraindications to liver transplantation. These findings may also have implications in the non-transplant setting as changes ascribed to specific etiologies for liver disease might include changes occurring in apparently healthy individuals.
A Transaction Cost Model of Electronic Trust: Transactional Return, Incentives for Network Security and Optimal Risk in the Digital Economy

Transaction cost economics can explain the mechanism by which network security technologies may reduce the interexchange costs between businesses in the supply chain and between businesses and customers in the digital economy. This paper develops the construct of technology-based electronic trust, where interpersonal, or “real” trust between people can be amplified and enhanced with the use of network security information technologies. The paper formally models an electronic commerce trust typology based on minimizing the cost of establishing trust in transactions, balanced against maximizing the potential user value from successfully completing transactions in the digital economy, suggesting that there is an optimal amount of acceptable risk in electronic commerce transactions. Sophisticated deployments of security information technologies may increase levels of interpersonal trust while lowering transaction costs in electronic commerce, thus promoting the long run development of neutral, interorganizational electronic markets and growth in the digital economy.
The “discovery” of alpha activity in lead and solder

More than 15 years ago the presence of 210Pb activity in lead was found to create significant background in a low-background radiation detection spectrometer. Shortly thereafter, 210Po alpha particles emitted from the surface of a solder joint were directly observed with this spectrometer. Antiquity lead was used to eliminate these sources of radioactivity. The experiments leading up to these “discoveries” are described. The magnitude of the effect of 210Pb in lead on the experiment is discussed. The sensitivities of various techniques for measuring 210Pb in lead are compared, and a practical limit for alpha activity in lead is proposed.
CAREER EARNINGS AND RETENTION OF U.S. MILITARY PHYSICIANS

Military physicians consider potential career earnings when making their stay/leave decisions. Moreover, they consider the effects of differences between military and civilian compensation at three distinct decision periods in the military career: the first year of unobligated service, the years after that point but before military retirement eligibility, and the year of retirement eligibility. We find that military retention is highly sensitive to compensation differences at the first decision and substantially less sensitive after that. We also account for endogeneity of military physician pay and retention with an instrumental variable technique, without which, estimates substantially underestimate the wage effect.
Caudal fin shape modulation and control during acceleration, braking and backing maneuvers in bluegill sunfish, Lepomis macrochirus.

SUMMARY Evolutionary patterns of intrinsic caudal musculature in ray-finned fishes show that fine control of the dorsal lobe of the tail evolved first, followed by the ability to control the ventral lobe. This progression of increasing differentiation of musculature suggests specialization of caudal muscle roles. Fine control of fin elements is probably responsible for the range of fin conformations observed during different maneuvering behaviors. Here, we examine the kinematics of the caudal fin and the motor activity of the intrinsic caudal musculature during kick-and-glide, braking and backing maneuvers, and compare these data with our previous work on the function of the caudal fin during steady swimming. Kick-and-glide maneuvers consisted of large-amplitude, rapid lateral excursion of the tail fin, followed by forward movement of the fish with the caudal fin rays adducted to reduce surface area and with the tail held in line with the body. Just before the kick, the flexors dorsalis and ventralis, hypochordal longitudinalis, infracarinalis and supracarinalis showed strong activity. During braking, the dorsal and ventral lobes of the tail moved in opposite directions, forming an `S9-shape, accompanied by strong activity in the interradialis muscles. During backing up, the ventral lobe initiated a dorsally directed wave along the distal edge of the caudal fin. The relative timing of the intrinsic caudal muscles varied between maneuvers, and their activation was independent of the activity of the red muscle of the axial myomeres in the caudal region. There was no coupling of muscle activity duration and electromyographic burst intensity in the intrinsic caudal muscles during maneuvers, as was observed in previous work on steady swimming. Principal-component analysis produced four components that cumulatively explained 73.6% of the variance and segregated kick-and-glide, braking and backing maneuvers from each other and from steady swimming. The activity patterns of the intrinsic caudal muscles during maneuvering suggest motor control independent from myotomal musculature, and specialization of individual muscles for specific kinematic roles.