cssi/SciSciGPT-SciSciNet huggingface dataset:
The interaction between bleomycin and radiation on cell survival and DNA damage in mammalian cell cultures

Chinese hamster ovary (CHO) cells were exposed to various concentrations of bleomycin (BLM) for 0.5, 1, 2, 4, 6, or 24 hours, followed with graded doses (0 to 800 rad) or radiation. The response to this chemotherapy-radiation combination treatment was measured by cell survival studies and DNA damage as determined by alkaline elution assay. Isobolograms for 1 and 2 log cell kills showed that cytotoxicity from BLM and from radiation were additive at 4, 15 and 75 milliunit/ml (mu/ml) for 1 or 4 hour exposure. When the exposure time of BLM was extended to 24 hours, slightly supraadditivity of lethality was found for the combination treatment with pharmacologically pertinent concentrations of 4 or 15 mu/ml. Therefore 4, 15 and 75 mu/ml concentrations of BLM all interacted positively with all doses of radiation to give enhanced cell kill. The alkaline elution patterns from the BLM-radiation combination also showed an enhancing effect on single strand breaks of DNA from treated cells. A human oat cell carcinoma cell line (MEMAR cells) was also studied and found to be more sensitive to BLM than were CHO cells.
EVIDENCE FOR A K*(1320) RESONANCE

It is suggested that the broad ${K}^{*}(890)\ensuremath{\pi}$ enhancement from 1.15 to 1.55 BeV is a complex phenomenon consisting of at least three parts: kinematic enhancement via the Deck mechanism, a possible new ${K}^{*}$ resonance at 1320 MeV, and an alternative decay mode of the ${K}^{*}(1430)$. It is further speculated that the ${A}_{1}$ and ${K}^{*}(1320)$ could be members of an octet.
Tracing atrial fibrillation--100 years.

Today, there is talk about an epidemic of atrial fibrillation. Dr. Bruce Fye recounts the clues that led clinical investigators to propose that atrial fibrillation was a common arrhythmia in patients with cardiac disease.
Comparison of 2 femtosecond lasers for flap creation in myopic laser in situ keratomileusis: one-year results.

Purpose To compare laser in situ keratomileusis (LASIK) outcomes between 2 femtosecond lasers for flap creation in the treatment of myopia up to 1 year. Setting University eye clinic. Design Prospective randomized eye-to-eye study. Methods Consecutive myopic patients were treated with wavefront-guided LASIK. One eye had a flap created by the Intralase FS 60 kHz femtosecond laser, and the fellow eye was treated with the Intralase iFS 150 kHz femtosecond laser. Eyes were randomized according to ocular dominance. Evaluations included measurement of uncorrected distance visual acuity (UDVA), corrected distance visual acuity, contrast sensitivity and wavefront aberrometry. Results The study enrolled 122 eyes of 61 patients. The mean preoperative spherical equivalent refraction was −4.62 diopters (D) ± 2.32 (SD) and −4.66 ± 2.30 D in the 150 kHz group and 60 kHz group, respectively. Patients preferred the 150 kHz laser to the 60 kHz laser intraoperatively (52.5% versus 26.2%) ( P = .005). One week postoperatively, UDVA was 20/16 or better in 85.2% in the 150 kHz group and 70.5% in the 60 kHz group; the difference was statistically significant ( P Conclusions Flap creation with the 150 kHz system and the 60 kHz system resulted in excellent LASIK outcomes. Intraoperatively, patients preferred the 150 kHz system, which yielded better UDVA in the early postoperative period. There were no significant differences at 1 year between the 2 laser systems. Financial Disclosure Proprietary or commercial disclosures are listed after the references.
SU‐GG‐T‐49: Improved Technique for Determining Y‐90 Glass Microsphere Activity Delivered

Purpose: Radioembolization of hepatic metastases with 90 Y microspheres requires that the user can accurately measure the source activity and consistently determine the completion of dose delivery. To determine the most effective technique for determining the completion of a single dose application, we have retrospectively examined dose rate measurements and source vial assays from 263 radioembolizations using Y‐90 glass microspheres. Method and Materials: Y‐90 glass microspheres were measured in an Atomlab 100 dose calibrator. Unit doses were supplied in 0.6 mL of sterile water contained in a v‐bottom vial secured within a 12 mm clear acrylic vial shield. Assays were obtained for the point source configuration (microspheres concentrated into the 0.3 ml v‐bottom) and for a distributed source configuration (microspheres distributed in 0.6 ml). Assayed values were compared to the nominal activity. Source dose rates were measured using Inovision 451P. Manufacturer's recommended measurements were followed. In addition, the beta dose rate from the top of the unshielded source vial was measured using Thermo Eberline RO7BM ionization chamber. Initial and final dose rate measurements were compared to the measured residual activity. Results: The axial dependence of the dose calibrators ranged from 0 to 5%. Measured activity in the point source configuration was on average 94.5% of the decayed calibrated activity (R2=0.996). However, measured activity in the distributed source configuration was on average 84.5% of the decayed calibrated activity (R2=0.998). Residual activity as a function of the beta specific dose rate measurements was linear (r2 = 0.4). Conclusion: This study has shown that using a point source configuration for source vial assays and using the beta specific dose rate measurements to accurately determine dose delivery does provide a more consistent and accurate determination of yttrium‐90 glass microsphere activity delivery and improve radioembolization quality assurance. Riad Salem, MD consultant for MDS‐Nordion.
Love and authentication

Passwords are ubiquitous, and users and service providers alike rely on them for their security. However, good passwords may sometimes be hard to remember. For years, security practitioners have battled with the dilemma of how to authenticate people who have forgotten their passwords. Existing approaches suffer from high false positive and false negative rates, where the former is often due to low entropy or public availability of information, whereas the latter often is due to unclear or changing answers, or ambiguous or fault prone entry of the same. Good security questions should be based on long-lived personal preferences and knowledge, and avoid publicly available information. We show that many of the questions used by online matchmaking services are suitable as security questions. We first describe a new user interface approach suitable to such security questions that is offering a reduced risks of incorrect entry. We then detail the findings of experiments aimed at quantifying the security of our proposed method.
Land Use and Climate Variability Amplify Contaminant Pulses

In 2002, the mid- Atlantic region experienced record drought levels. In September 2003, Tropical Storm Isabel produced large amounts of rainfall in the Chesapeake Bay region, and freshwater flow into the Chesapeake Bay was 400% above the long- term monthly average (http://chesapeake.usgs.gov/isabelinfo.html). Record drought conditions followed by a very wet year coincided with pulsed watershed nitrogen exports and one of the most severe zones of hypoxia, or “dead zones,” reported in the Chesapeake Bay. Large pulses of contaminants such as this event may occur more often given evidence of increased variability of precipitation and hydrologic extremes occurring with climate change [Intergovernmental Panel on Climate Change (IPCC), 2007]. Conversion of land to human- dominated uses has increased contaminant loads in streams and rivers and further transformed hydrologic cycles [Vitousek et al., 1997]. Together, land use and climate change may interact in unexpected ways to alter the amplitude, frequency, and duration of contaminant pulses in streams and rivers (i.e., large contaminant loads that are transported over relatively short time scales).
The competitive influence of specific interactions and extent of reaction on the miscibility of ternary reactive polymer blends: model for polyurethane adhesives

A ternary blend of polyether, polyester and an acrylic was used to model a polyurethane-based reactive hot melt adhesive. The miscibility behavior of this ternary blend was found to change significantly during formation of the polyurethane prepolymer. The competing effects of changing the functionality and increasing the molecular weight of polyether and polyesters have been analyzed. It was found that incorporation of urethane groups tends to improve ternary blend miscibility. In contrast, an increase in the molecular weight of the prepolymer destabilizes the ternary blends. These competing effects cause an oscillation in the free energy of mixing. For prepolymers with low molecular weight, the ternary blend can exist as miscible or immiscible mixtures as a function of molecular weight. The results of this study are useful in understanding how the phase behavior of reactive polyurethane blends evolves as a function of the extent of reaction and the distribution of the reaction products formed.
Correlation of single-lumen silicone implant integrity with chemical shift artifact on T2-weighted magnetic resonance images.

Purpose To correlate the integrity of single-lumen silicone gel implants with chemical shift artifact (CSA) associated with infolding of the elastomer shell. Materials and Methods The T2-weighted images of presurgical MRI examinations of 54 implants were retrospectively reviewed by two breast radiologists blinded to the operative and pathologic findings. CSA associated with intraluminal membranes was quantified by determining the fraction of membranes with it and categorized as minimal (0–⅓ of membranes involved), moderate (>⅓ – <⅔), and marked (⅔ to all). CSA was qualified by noting whether CSA intensity of the membranes was less than or similar to that of blood vessels. The CSA was correlated with the surgical or pathology findings to judge integrity of the implant. Results Nineteen implants were intact, 35 were dysfunctional (gel leakage or rupture). Twenty-eight of 29 (97%) with a minimal fraction of membranes with CSA were dysfunctional; 17/21 (81%) with CSA associated with a marked fraction of membranes were intact (P < 0.001). All 28 implants with CSA intensity less than vessels were dysfunctional, 19/26 (73%) with CSA equal to vessels were intact (P < 0.001). All 25 implants with minimal CSA and intensity less than vessels were dysfunctional. Seventeen of 19 (89%) implants with CSA associated with a marked fraction of membranes and intensity equal to vessels were intact (P = 0.02). The magnetic resonance imaging (MRI) signs were combined with strong CSA as a predictor of integrity, and 22 of 26 (85%) implants were correctly diagnosed, 4 dysfunctional and 18 intact (P < 0.0001). Conclusion CSA correlates with integrity of silicone gel implants on T2-weighted images and can be used with other MRI signs to improve diagnosis. J. Magn. Reson. Imaging 2002;15:159–164. © 2002 Wiley-Liss, Inc.
Study of intrinsic localized vibrational modes in micromechanical oscillator arrays.

Intrinsic localized modes (ILMs) have been observed in micromechanical cantilever arrays, and their creation, locking, interaction, and relaxation dynamics in the presence of a driver have been studied. The micromechanical array is fabricated in a 300 nm thick silicon–nitride film on a silicon substrate, and consists of up to 248 cantilevers of two alternating lengths. To observe the ILMs in this experimental system a line-shaped laser beam is focused on the 1D cantilever array, and the reflected beam is captured with a fast charge coupled device camera. The array is driven near its highest frequency mode with a piezoelectric transducer. Numerical simulations of the nonlinear Klein–Gordon lattice have been carried out to assist with the detailed interpretation of the experimental results. These include pinning and locking of the ILMs when the driver is on, collisions between ILMs, low frequency excitation modes of the locked ILMs and their relaxation behavior after the driver is turned off.
Turbulence Associated with Broadband Shock Noise in Hot Jets

Time-Resolved Particle Image Velocimetry (TRPIV) has been applied to a series of jet flows to measure turbulence statistics associated with broadband shock associated noise (BBSN). Data were acquired in jets of Mach numbers 1.05, 1.185, and 1.4 at different temperatures. Both convergent and ideally expanded nozzles were tested, along with a convergent nozzle modified to minimize screech. Key findings include the effect of heat on shock structure and jet decay, the increase in turbulent velocity when screech is present, and the relative lack of spectral detail associated with the enhanced turbulence.
Structures of the Escherichia coli transcription activator and regulator of diauxie, XylR: an AraC DNA-binding family member with a LacI/GalR ligand-binding domain

Escherichia coli can rapidly switch to the metabolism of l-arabinose and d-xylose in the absence of its preferred carbon source, glucose, in a process called carbon catabolite repression. Transcription of the genes required for l-arabinose and d-xylose consumption is regulated by the sugar-responsive transcription factors, AraC and XylR. E. coli represents a promising candidate for biofuel production through the metabolism of hemicellulose, which is composed of d-xylose and l-arabinose. Understanding the l-arabinose/d-xylose regulatory network is key for such biocatalyst development. Unlike AraC, which is a well-studied protein, little is known about XylR. To gain insight into XylR function, we performed biochemical and structural studies. XylR contains a C-terminal AraC-like domain. However, its N-terminal d-xylose-binding domain contains a periplasmic-binding protein (PBP) fold with structural homology to LacI/GalR transcription regulators. Like LacI/GalR proteins, the XylR PBP domain mediates dimerization. However, unlike LacI/GalR proteins, which dimerize in a parallel, side-to-side manner, XylR PBP dimers are antiparallel. Strikingly, d-xylose binding to this domain results in a helix to strand transition at the dimer interface that reorients both DNA-binding domains, allowing them to bind and loop distant operator sites. Thus, the combined data reveal the ligand-induced activation mechanism of a new family of DNA-binding proteins.
Synthesis of phytochelatins in vetiver grass upon lead exposure in the presence of phosphorus

In a hydroponic setting, we investigated the possible role of phytochelatins (metal-binding peptides) in the lead (Pb) tolerance of vetiver grass (Vetiveria zizanioides L.). Pb was added to the nutrient medium at concentrations ranging from 0 to 1,200 mg L−1. Furthermore, we simulated the effect of soil phosphorus (P) on potentially plant available Pb by culturing vetiver grass in P-rich nutrient media. After 7 days of exposure to Pb, we evaluated the Pb uptake by vetiver grass. Results indicate that vetiver can accumulate Pb up to 3,000 mg kg−1 dry weight in roots with no toxicity. Formation of lead phosphate inhibited Pb uptake by vetiver, suggesting the need for an environmentally safe chelating agent in conjunction with phytoremediation to clean up soils contaminated with lead-based paint. Unambiguous characterization of phytochelatins (PCn) was possible using high pressure liquid chromatography coupled with electrospray ionization mass spectrometry (LC-ESMS). Vetiver shows qualitative and quantitative differences in PCn synthesis between root and shoot. In root tissue from vetiver exposed to 1,200 mg Pb L-1, phytochelatins ranged from PC1 to PC3. Collision-induced dissociation of the parent ion allowed confirmation of each PCn based on the amino acid sequence. Possible Pb-PC1 and Pb2-PC1 complexes were reported in vetiver root at the highest Pb concentration. The data from these experiments show that the most probable mechanism for Pb detoxification in vetiver is by synthesizing PCn and forming Pb–PCn complexes.
Novel chemistry of the extraordinary acid (CF3SO2)2NH

Abstract The synthesis of the remarkable acid, (CF3SO2)2NH, has been refined to provide the acid in high yield and high purity. A number of new derivatives will be described, including the Ag(I) and Tl(I) salts. The latter are useful reagents for the synthesis of both organic and inorganic derivatives of the acid. The Ag(I) compound shows many similarities to silver triflate and forms complexes with many neutral ligands. A mixture of AgN(SO2CF3)2 and RI in appropriate solvents represent a powerful alkylating medium. The N-fluoro derivative, (CF3SO2)2NF, is a remarkable fluorination reagent which may have wide applicability in selective fluorinations.
Hummingbird foraging behavior in different patch types: simulation of alternative strategies

The development of a model simulating alternative hummingbird foraging strategies is described and predictions of the model are compared with foraging patterns recorded in the field. The hypotheses that: (1) natural foraging patterns more closely resembled systematic foraging than random foraging; and (2) systematic foragers were more efficient when resource distributions were clumped versus random were tested. Simulated foraging strategies included random, area-restricted, and directional foraging. The random strategy randomly selected the flowers a hummingbird visited. The area-restricted strategy allowed a hummingbird to visit any flower directly adjacent to the current flower, with an equal probability of visiting any adjacent flower. The directional strategy was based on the previous and current flowers visited, with a hummingbird following a straight path until it encountered an edge. At an edge, the hummingbird had an equal probability of turning and moving in any direction. A three-flower memory was incorporated into the strategies, so a simulated hummingbird could not revisit the last three flowers visited. During field trials and simulations, hummingbirds foraged in patches of 36 artificial flowers with uniform, clumped, and random nectar distributions. All the flowers in a uniform patch contained nectar. A clumped patch consisted of clumps of four rewarding flowers interspersed with clumps of four empty flowers. A random patch contained randomly distributed rewarding and empty flowers. Foraging efficiency for the field foraging patterns was measured and foraging strategies were simulated as microliters of nectar consumed per time step, assuming higher rates of consumption were more efficient than lower rates of consumption. In random patches, the field foraging patterns were more efficient than the simulated foraging strategies, whereas the field foraging patterns and area-restricted strategy were the most efficient in clumped patches. In the uniform patch, the directional strategy was the most efficient, followed by the field foraging patterns and random strategy. The random strategy was more efficient in patches with random versus clumped nectar distributions, whereas the area-restricted strategy was more efficient in clumped patches. No differences existed between clumped and random patches for the directional strategy or field foraging patterns. These results suggested the hummingbirds used different foraging rules in different patch types and incorporated information not included in the simulated strategies into their foraging patterns. This approach of replicating field experiments with a spatially explicit simulation model provides a valuable methodology for evaluating the effectiveness of different foraging strategies under different patterns of resource availability.
Molecular genetic basis of familial ALS

Familial amytrophic lateral sclerosis (FALS) is transmitted in a mendelian fashion as an autosomal dominant (DFALS) or an autosomal recessive (RFALS) trait.Both DFALS and RFALS are genetically heterogeneous. Fifteen percent of DFALS families have mutations in the gene for Cu, Zn superoxide dismutase (SOD1) which is coded on chromosome 21. The locus for one form of RFALS maps to chromosome 2q33. Forty-six mutations in the SOD1 gene have been reported in DFALS families. These mutations result in decreased SOD1 activity and shortened half-life of the protein in most instances. Transgenic mice overexpressing mutated SOD1 protein develop an ALS-like disease which suggests that the degeneration of motor neurons in DFALS is caused by the gain of a novel toxic function by mutated SOD1 rather than by the decrease of SOD1 activity. Several possible mechanisms of the novel neurotoxic function of mutated SOD1 are discussed. NEUROLOGY 1996;47(Suppl 2): S27-S35
Nondestructive sampling of human skeletal remains yields ancient nuclear and mitochondrial DNA

Museum curators and living communities are sometimes reluctant to permit ancient DNA (aDNA) studies of human skeletal remains because the extraction of aDNA usually requires the destruction of at least some skeletal material. Whether these views stem from a desire to conserve precious materials or an objection to destroying ancestral remains, they limit the potential of aDNA research. To help address concerns about destructive analysis and to minimize damage to valuable specimens, we describe a nondestructive method for extracting DNA from ancient human remains. This method can be used with both teeth and bone, but it preserves the structural integrity of teeth much more effectively than that of bone. Using this method, we demonstrate that it is possible to extract both mitochondrial and nuclear DNA from human remains dating between 300 BC and 1600 AD. Importantly, the method does not expose the remains to hazardous chemicals, allowing them to be safely returned to curators, custodians, and/or owners of the samples. We successfully amplified mitochondrial DNA from 90% of the individuals tested, and we were able to analyze 1-9 nuclear loci in 70% of individuals. We also show that repeated nondestructive extractions from the same tooth can yield amplifiable mitochondrial and nuclear DNA. The high success rate of this method and its ability to yield DNA from samples spanning a wide geographic and temporal range without destroying the structural integrity of the sampled material may make possible the genetic study of skeletal collections that are not available for destructive analysis.
Vertebral augmentation in the treatment of pathologic compression fractures in 792 patients with multiple myeloma.

Vertebral augmentation in the treatment of pathologic compression fractures in 792 patients with multiple myeloma
Behavior of Composite Shells Under Transverse Impact and Quasi-Static Loading

The impact and quasi-static response of various composite shell structures to transverse loading was studied experimentally. In particular, the effect of varying structural parameters (radius, span, and thickness) on the loading response, including damage resistance, is explored. The AS4/3501-6 graphite/epoxy composite structures considered have a [±45 n /0 n 1s layup configuration (n = 1, 2, 3) and include convex and concave shell sections, plates, and full cylinders. All structural parameters are found to affect the response, particularly characteristics of the instability associated with the convex shell behavior and the structural stiffness. Trends with regard to peak force and structural stiffness with the structural parameters are established and discussed. Specimen thickness is noted to have the greatest effect of all the parameters, but shell radius is clearly important due to the instability that it introduces. Damage resistance trends with structural parameters are established and linked to peak force. Although linked to peak force, these damage trends are also found to be dependent upon whether the peak force occurs before or after the shell instability. The results of this work establish the effects of structural parameters on the general response characteristics, including damage resistance, of composite shells under transverse loading with application to low-velocity impact. Thus, these results provide benchmark data for comparison with analytical and numerical, e.g., finite element, studies. Suggestions for areas of further work are provided.
Solvation Dynamics in Protein Environments Studied by Photon Echo Spectroscopy

Photon echo spectroscopy is used to study the mechanisms of solvation dynamics in protein environments at room temperature. Ultrafast and additional multi-exponential long time scales are observed in the three-pulse photon echo peak shift data of the fluorescein dye eosin bound to lysozyme in aqueous solution. The dynamics of the solvated lysozyme are characterized with dielectric continuum models that integrate dielectric data for water with that for lysozyme. By comparing our data with previous results for eosin in water [Lang, M. J.; Jordanides, X. J.; Song, X.; Fleming, G. R. J. Chem. Phys. 1999, 110, 5584], we find that the total coupling of the electronic transition frequency of eosin to the nuclear motions of the aqueous lysozyme solution is smaller than in the aqueous solution. On an ultrafast time scale, solvation appears to be dominated by the surrounding water and not by the ultrafast internal motions of lysozyme. However, over long time scales, lysozyme does contribute significantly, either di...
Apparent gas-phase acidities of multiply protonated peptide ions: Ubiquitin, insulin B, and renin substrate.

The gas-phase deprotonation reactions of multiply protonated bovine ubiquitin, insulin chain B, and renin substrate tetradecapeptide ions have been studied in a Fourier transform ion cyclotron resonance mass spectrometer coupled with an external electrospray source. Rate constants were measured for the reactions of these peptide ions with a series of reference compounds of known gas-phase basicities ranging from 195.6 to 232.6 kcal/mol. The apparent gas-phase acidities (GAapp) of the multiply protonated peptide ions [M + nH]n+ were determined with deprotonation reactions. The deduced values of GAapp show a strong dependence on the charge states of the multiply protonated peptide ions. In general, the values decrease as the charge states of the peptide ions increase. For ubiquitin ions, the determined GAapps values decrease from >232.6 to 205.0 kcal/mol for n=4–13; for insulin B ions, the GAapps decrease from >232.6 to 198.2 kcal/mol for n=2–5; for renin substrate ions, the GAapps decrease from 221.6 to <195.6 kcal/mol for n=2–4. Interestingly, at a given mass-to-charge ratio, the GAapps of these peptide ions agree within 10 kcal/mol despite large differences in their mass and charge. The ubiquitin and insulin B ions generated under the present conditions reveal multiple isomers at certain charge states, n=4, 5, 6, 12 for ubiquitin and n=4, 5 for insulin B, as evidenced by the fact that the isomers display distinctively different deprotonation reaction rates with certain reference compounds.
The use of electrophysiology for the assessment of diabetic neuropathy

Whole nerve electrophysiology can provide a battery of objective, reliable and specific measures that are sensitive to the progression of diabetic symmetrical polyneuropathy (DSPN). However, under standard conditions, these measures index limited aspects of neural activity, and then only in large diameter, myelinated axons. Nerve conduction is not synonymous with "nerve function." Electrophysiologic measures can be influenced by a variety of factors with different time courses of action and with different sensitivities to manipulation. The value of whole nerve electrophysiology must be based on a firm appreciation of the strengths and limitations of the procedure. © 1997 John Wiley & Sons, Ltd.
EFFECTS OF 16,16-DIMETHYL PROSTAGLANDIN E2 ON GLYCOPROTEIN AND LIPID SYNTHESIS OF GASTRIC EPITHELIAL CELLS GROWN IN A PRIMARY CULTURE

We investigated the biosynthesis of phospholipid, neutral lipids, glycoproteins, and DNA in primary cultures of rat oxyntic mucosal cells. In addition, responses of these biosynthetic pathways to the gastric protective agent 16,16-dimethyl prostaglandin E2 (dmPGE2) were studied. Cultured gastric cells under control conditions synthesized glycoprotein in a linear manner over time. The cells responded to dmPGE2 with an increase in glycoprotein synthesis without an effect on DNA synthesis. Investigations of lipid synthesis showed that phospholipid was produced in a linear fashion by these cells, however, no effect of exogenously administered dmPGE2 on its rate of formation was discernible. In contrast, the incorporation of labeled palmitate into neutral lipids revealed that triglyceride biosynthesis was significantly increased by the addition of dmPGE2 to the culture medium, which could be further enhanced by the administration of the phosphodiesterase inhibitor, isobutyl methyl xanthine. Cyclic nucleotide involvement was further suggested by our finding that triglyceride synthesis in cultured gastric mucous cells could be increased a comparable amount by the addition of both dbcAMP and dbcGMP to the medium. The possible relationship between these biochemical alterations and the gastric protective action of dmPGE2 is discussed.
Aging in epidermal melanocytes: cell cycle genes and melanins.

With aging, melanocytes become unevenly distributed in the epidermis. In light skin individuals, hypo-pigmentation is found in association with focal hyper-pigmentation (lentigo senilis). Apparently this results from progressive loss of active melanocytes and focal increase in melanocyte proliferation and/or aggregation. This paper summarizes the present knowledge on aging of melanocytes in vivo and in vitro, with a focus on the role of melanin as a determinant for proliferation and terminal differentiation. We describe that excessive melanin deposition by cyclic AMP-inducing agents results in increased expression of the cyclin-dependent kinase inhibitors P27Kip-1 and p21SDI-1/Waf-1, increased binding of p16 to CDK4, and terminal differentiation. Journal of Investigative Dermatology Symposium Proceedings 3:36– 40, 1998 Importantly, the efficiency with which the melanocytes exit the cell cycle depends on the melanin background of the donor's cells. Melanocytes from skin types IV–VI that accumulate large amounts of brown black melanin (eumelanin), lose expression of the transcription factors E2F1 and E2F2, two key regulatory proteins, and withdraw from the cell cycle more rapidly than melanocytes from skin types I and II that accumulate red/yellow melanin (pheomelanin). Thus, we propose that terminal differentiation is a tumor suppressor mechanism that becomes less efficient under imperfect eumelanization.
Preparation of Alkyl Esters of Pectin and Pectic Acid

Alkyl esters of pectin and pectic acid have been prepared via three different synthetic routes. Enhancements of intrinsic viscosity, binding to bile acids and to isolated soy protein were shown for these novel pectin derivatives. The development of new and improved pectin-containing products may be enhanced by the ease of preparation and improved functionality of such compounds.
CONFORMALLY EUCLIDEAN INTERNAL COORDINATE SPACE IN THE QUANTUM THREE-BODY PROBLEM

Abstract The internal coordinate space for three particles of arbitrary mass is shown to be a three-dimensional conformally Euclidean space. This gives the internal kinetic energy operator a simple form and provides a unified view of the different hyperspherical coordinates used in quantum three-body problems.
Italia linguistica and the European Charter for Regional or Minority Languages

The European Charter for Regional or Minority Languages requires member states that have ratified and signed to support the survival and use of longstanding minority languages within their borders. While the Charter offers some guidance in the selection of qualified languages, its definitions are far from rigorous and leave considerable room for arbitrary selection. Moreover, the selections are left entirely to government entities of each state. The result in the case of Italy is that a very small collection of the nation’s plethora of languages has been deemed worthy of support. This article urges reconsideration of the decision-making process in light of the plurilinguistic reality of Italy and the Charter’s purpose of guaranteeing linguistic minorities the integrity of their voice.
Spin-rotation relaxation times for methyl compounds with hindrance barriers at 65°C

Abstract The 13C spin-rotation relaxation times of methyl groups with a range of potential barriers to hindered rotation were measured for five compounds at 65°C. The data follow a pattern similar to those obtained earlier at 10°C and 38°C, and agree well with the theoretical results of Mendonca et al.
Thermographic observations on rats with experimental neuropathic pain.

Abstract Infrared thermographic images were obtained from the plantar hind paws of rats with an experimental nerve injury that produces signs of neuropathic pain. Thermograms confirmed that the experimental neuropathy produces signs resembling those of patients with neuropathic pain. The hind paws on the nerve-damaged side were abnormally hot, abnormally cold, or apparently normal 8–16 days post injury, a variability that is seen clinically in neuropathic pain patients. Abnormally cold hind paws became warm as soon as the injured sciatic nerve was transected, indicating that the underlying vasoconstriction was mediated by neural impulse activity. Xylazine (Rompun), a sympatho-inhibitory α 2 -adrenoceptor agonist that normally increases cutaneous temperature, caused the hind paw on the control side to warm, as anticipated, while causing paradoxical cooling of abnormally hot hind paws, and even of ‘normal temperature’ paws on the nerve-injured side. These findings shed light on possible mechanisms underlying abnormal deviations of skin temperature as a symptom of nerve injury. The findings also attest to the usefulness of the experimental animal model of neuropathic pain and of the thermographic method.
Identification and Control of Processes with Periodic Operations or Disturbances

Periodically time-varying (PTV) systems are commonly used to model natural and forced periodic phenomena encountered in many engineering applications. We propose an approach in which the subspace i...
Neurocysticercosis and acquired cerebral toxoplasmosis in children.

Neurocysticercosis, prevalent wherever pigs are ralsed in the presence of poor sanitation, is the most common identifiable cause of new-onset epilepsy throughout the developing world. As immigration patterns have changed, children with neurocysticercosis are seen throughout the United States. Acute cysticercosis, the most common manifestation in children, reflects the host response to the dying parasite. Children typically present with seizures and have an excellent prognosis. Neuroimaging demonstrates a single ring or nodular enhancing lesion surrounded by edema. Short-term anticonvulsant therapy is indicated, but treatment with antiparasitic agents is not required. Other forms, such as active cysts (intact organism), intraventricular or subarachnoid racemous cysticercosis, and cysticercal meningoencephalitis, are less common manifestations of parasitic infection. Toxoplasmosis, caused by the parasite Toxoplasma gondii , can be acquired by ingestion of infected undercooked meat or from oocytes shed in cat feces. Acquired cerebral toxoplasmosis, due to primary or reactivated infections, rarely occurs in immunocompetent children. In children who are immunodeficient as the result of AIDS, chemotherapy, tissue transplantation, or congenital immunodeficiency, toxoplasmosis may be difficult to distinguish from cerebral lymphoma. A variety of techniques, including neuroimaging, Thallium-201 SPECT, polymerase chain reaction analysis of CSF, and special histological methods, may be used to diagnose acquired toxoplasmosis. Antiparasitic therapy, using pyrimethamine and sulfadiazine, and serial neuroimaging often enable clinicians to differentiate toxoplasmosis from other central nervous system lesions. Toxoplasmosis may respond to other antimicrobials, including macrolide antibiotics, dapsone, clinidamycin, and atovaquone. Suppressive treatment is generally required for life in immunodeficient patients. Immunodeficient children with acquired toxoplasmosis have high rates of mortality and neurological sequelae.
SPINAL CORD COMPRESSION DUE TO EXTRAMEDULLARY HEMATOPOIESIS IN BETA-THALASSEMIA INTERMEDIA

Abstract Background: Extramedullary hematopoiesis (EMH) occurs in many disorders, including thalassemias and other hemoglobinopathies, and commonly presents in the spleen and liver. We present a case of spinal cord compression in a patient with beta-thalassemia intermedia, and review the literature and available treatment options. Patient and Methods: A 35-year-old black female with beta-thalassemia intermedia presented with a 3-week history of back pain and lower extremity weakness. Neurologic examination was consistent with spinal cord compression, and gadolinium enhanced magnetic resonance imaging (MRI) confirmed this diagnosis. She was given intravenous steroids and radiotherapy was begun in 200 cGy fractions to a total dose of 2000 cGy. Results: At the completion of radiotherapy the patient was ambulatory with mild residual weakness. MRI scans 16 months later showed smaller, but persistent masses, and she remains asymptomatic 5 years from her diagnosis. Conclusion: Recognition of spinal cord EMH requires prompt physical examination and MRI for accurate diagnosis. EMH can be managed with radiation, surgery, transfusions, or a combination of these therapies. Radiation in conservative doses of (750–3500 cGy) is non-invasive, avoids the surgical risks of potentially severe hemorrhage and incomplete resection, and has a high complete remission rate in the majority of patients. Relapse rates are moderate (37.5%), but retreatment provides excellent chance for second remission.
Miscibility gap and critical point behavior for a cubic margules solution model

It is pointed out that a four parameter, binary solution model, in which the temperature independent enthalpy and excess entropy of mixing are cubic functions of the atom fraction, has provided quantitative fits to the thermodynamic properties of many metallic solution phases. It is therefore desirable to understand this semi-empirical model, in particular its miscibility gap and critical point behavior. It is shown that the latter is governed by two parameters, ϵ and η, that depend upon the temperature and the values of the four, temperature and composition independent, solution parameters. ϵ is the excess Gibbs free energy of mixing at x = 12 divided by RT/4. The parameter η is the difference in the excess chemical potentials at x = 12 divided by RT/4. The solution parameters define half of an infinite straight line in the ϵ-η plane called the constant-parameter trajectory, whereas the classical critical points fall along a parabola-like curve through ϵ = 2, η = 0. The appearance or disappearance of a miscibility gap is associated with the intersection of the constantparameter trajectory and the critical locus. The critical composition can be anywhere. Besides the normal miscibility gap, an inverted gap that first appears at high temperatures can occur and both types can occur in the same system. Equations for the gap width and asymmetry that are asymptotically correct near the critical temperature are developed. These show how the magnitude of the gap-width depends upon the solution parameters for a given temperature and critical point. The results are illustrated by application to some III–V systems and in obtaining a quantitative fit to the Pb-Ga system.
Urban homicide: Still the same

We use 1984–1986 data to estimate lifetime risks of being murdered in each of 50 large American cities and then compare these projections to others made earlier from 1971–1972 and 1976–1977 data. We find strong constancy over time in the average urban resident's murder risk (essentially a 1 in 68 chance of eventually being slain). Moreover, we find a high stability in the dispersion of risk by region, race, and city size and in the relative rankings of the 50 cities by murder risk. We comment briefly about such recent phenomena as the proliferation of crack and the resumption of capital punishment.
The value of knowledge spillovers in the U.S. semiconductor industry

Abstract This paper aims at quantifying the economic value of knowledge spillovers by exploring information contained in patent citations. We estimate a market valuation equation of the U.S. semiconductor firms during the 1980s and 1990s, and find an average value of $0.6 to 1.2 million “R&D-equivalent” dollars for knowledge spillovers embodied in one patent citation. For an average semiconductor firm, such an estimate implies that the total value of knowledge spillovers the firm received during the sample period can be as high as half of its actual total R&D expenditures in the same period. This provides a direct measure of the economic value of social returns or externalities of relevant technological innovations. We also find that the value of knowledge spillovers declines as the size of firm's patent portfolio increases, and that self citations are more valuable than external citations, indicating a significant amount of tacit knowledge or know-how spillovers that occur within the firm.
EXPERIMENTALLY-INDUCED MAGNESIUM DEFICIENCY IN GROWING KITTENS

Abstract Experiments were conducted to determine the effects of a dietary inadequacy of, and to estimate the dietary requirement for magnesium (Mg) in the growing Kitten. In Experiment 1, fourteen Kittens were fed a casein-based diet containing 50 mg/kg Mg without supplemental Mg or supplemented with 700 mg/kg Mg. Muscular weakness, hyperirritability, convulsions, reduced feed intake and poor growth were observed in kittens fed 50mg/kg Mg. Additionally, these animals exhibited reduced serum and bone Mg, and increased soft tissue calcium (Ca) concentrations. Graded levels of dietary Mg were fed in Experiment 2 (100, 400 and 700 mg/kg) and Experiment 3 (400, 550 and 700 mg/kg) to estimate the dietary requirement for Mg in the young kitten. Gross manifestations of a Mg deficiency were not observed. Serum Mg concentration declined within one week after kittens were fed 100mg/kg Mg, but were unchanged by feeding of 400, 550 or 700 mg/kg Mg. Calcium concentration was increased in aorta, liver and skeletal muscle, but not in kidney, and bone Mg concentration was reduced when kittens were fed 100 mg/kg Mg. No significant changes were observed in soft tissue Ca or bone Mg when kittens were fed diets supplemented to 400, 550 or 700 mg/kg Mg. We conclude that 400 mg/kg dietary Mg is adequate for growth, maintenance of blood and tissue Mg and prevention of calcification of soft tissues.
Health-Promoting Self-Care Behaviors, Self-Care Self-Efficacy, and Self-Care Agency

The relationships among health-promoting self-care behaviors, self-care self-efficacy, and self-care agency were investigated. The purpose of the study reported here was to explore conceptual integration that could be useful in determining interventions that enhance self-care agency. The sample consisted of 379 adult subjects. The instrumentation scales included: Health-Promoting Lifestyle Profile II, Self-Rated Abilities for Health Practices, and Exercise of Self-Care Agency. A canonical correlation identified a significant variate with a correlation of .76 (p < .001) accounting for 58% of the variance explained. The loading variables included: spiritual growth, self-concept, initiative, and responsibility. Therefore, spiritual growth was more strongly related to self-care agency than self-efficacy.
Induction of monozygotic twinning by ascorbic acid in tobacco.

Embryo development in plants initiates following the transverse division of a zygote into an apical, proembryo cell and a basal cell that gives rise to the suspensor. Although mutants affected in embryo development through changes in cell division have been described, little is known about the control of the first zygotic division that gives rise to the proembryo. Ascorbic acid (Asc) promotes cell division by inducing G1 to S progression but its role in embryo development has not been examined. In this study, we show that the level of dehydroascorbate reductase (DHAR) expression, which recycles Asc and regulates Asc pool size, affects the rate of monozygotic twinning and polycotyly. DHAR-induced twinning resulted from altered cell polarity and longitudinal instead of transverse cell division that generated embryos of equal size. Direct injection of Asc into ovaries phenocopied DHAR-induced twinning. Twinning induced by Asc was developmentally limited to the first two days after pollination whereas polycotyly was induced when the level of Asc was elevated just prior to cotyledon initiation. This work describes the first example of gene-directed monozygotic twinning and shows that Asc regulates cell polarity during embryo development.
The effects of word frequency and context variability in cued recall

Normative word frequency and context variability affect memory in a range of episodic memory tasks and place constraints on theoretical development. In four experiments, we independently manipulated the word frequency and context variability of the targets (to-be-generated items) and cues in a cued recall paradigm. We found that high frequency targets were better recalled in both pure and mixed lists, even when context variability was held constant. High frequency cues were slightly more effective, but this benefit was eliminated when context variability was held constant. Low context variability cues were most effective while the context variability of the target had little effect on performance. The data suggest that words with fewer pre-experimental connections are better able to isolate the list and that generation of an item from memory benefits from frequency, perhaps due to the ease of generating common orthographic and phonological features. Implications for current models of memory and the prospects of future models are discussed.
Comment on: “Do Sunspots Matter When Spot Market Equilibria Are Unique?”

Mas-Colell (1992) conjectured that there could be no sunspot equilibria if the fun­ damentals of the underlying economy admitted a unique equilibrium. Hens (2000) con­ structed an example to show that this conjecture was false. A weak form of Mas-Colell's conjecture is indeed false, but there is an error in Hens's proof. The first part of this com­ ment shows the mistake in Hens's argument, and the second part proves the existence of the relevant sunspot equilibria. We conclude with a discussion of why an example like Hens's is necessary if one wishes to prove that a stricter form of Mas-Colell's conjecture is indeed false. W e follow Hens's notation almost exactly. There are two sunspot-contingent assets paying returns denominated in units of the numeraire. These returns are  
Queue Size and Delay Analysis for a Communication System Subject to Traffic Activity Mode Changes

We consider a discrete single-server queueing/communication system, in which the arrival distribution is changing stochastically with time. The distribution of the number of messages to arrive within a time slot depends on a traffic activity process of modes. This process of modes is a two-state Markov chain: mode 0 and mode 1, which represent light and heavy traffic conditions, respectively. The transition probabilities of this Markov chain [herein called mode duration parameters (MDP's)] determine the distribution of the duration of time the process stays in each mode. Expressions for the z -transform, expectation, and variance are obtained for the steady-state queue size and delay. A special consideration is given to the effect of the MDP's on the system performance, and the limiting cases (where the MDP's approach zero) are studied.