cssi/SciSciGPT-SciSciNet huggingface dataset:
Long-term results of antegrade endoureterotomy using the holmium laser in patients with ureterointestinal strictures

Abstract Objectives. To investigate the effectiveness and morbidity of percutaneous laser endoureterotomy in the management of ureterointestinal anastomotic strictures after radical cystectomy and urinary diversion. Methods. Between May 1997 and August 2000, 19 percutaneous endoureterotomy incisions, including 3 repeated incisions, were performed on 15 patients with a mean age of 61 years (range 41 to 80) to treat ureterointestinal strictures. A total of 16 renal units were treated (9 left, 7 right), including one bilateral procedure. All procedures were performed using a 200-μm holmium laser fiber in antegrade fashion with a 7.5F flexible ureteroscope. A nephroureteral stent was left in place for 4 to 6 weeks postoperatively. Success was defined as radiologic improvement and/or the ability to return to full activity in the absence of flank pain, infection, or the need for ureteral stents or nephrostomy tubes. Results. With a median follow-up of 20.5 months (range 9 to 41), the overall success rate was 57% (8 of 14 renal units). Two patients were lost to follow-up. The mean operative time was 91 minutes, and no perioperative complications occurred. Three patients required repeated endoureterotomies, with two requiring open reimplantation. Overall, the endoureterotomy failed in 6 patients in the series, with five of the six failures involving left-sided strictures. Conclusions. Percutaneous endoureterotomy is an effective, minimally invasive treatment option for patients with ureterointestinal strictures after urinary diversion. Better visualization and a more precise incision may make the holmium laser a safer cutting modality than alternative methods in patients with ureteroenteric strictures. Patients with left-sided ureterointestinal strictures should be cautioned that endourologic management might have a lower success rate.
On the nature of desmoplastic melanoma

Pathologic study demonstrated lentigo maligna melanoma in three of four cases of desmoplastic melanoma and demonstrated spindle cell masses with features of atypical fibroxanthoma in all four of the cases. Pigment enzymes of melanosomes were not found in the mesenchymal portion of the tumor. The cellular atypia and the histochemical and ultrastructural findings favor the fibroblastic nature of this melanoma-related dermal mass.
Gallium(III) triflate: an efficient and a sustainable Lewis acid catalyst for organic synthetic transformations.

Green chemical processes play a crucial role in sustainable development, and efficient recyclable catalysts that can be conveniently applied in various chemical reactions are the key elements for the development of sustainable synthetic processes. Many organic transformations rely on Lewis and Bronsted acid catalysts, and such molecules have been widely studied in organic synthesis. Over the years, researchers have looked for Lewis acid catalysts that provide high selectivity and high turnover frequency but are also stable in aqueous media and recoverable. Since the first preparation of trifluoromethanesulfonic acid by Hazeldine (triflic acid, HOTf), researchers have synthesized and used numerous metal triflates in a variety of organic reactions. Even though the rare earth metal triflates have played a major role in these studies, the majority of rare earth triflates lack one or more of the primary properties of sustainable catalysts: low cost and easy availability of the metals, easy preparation of trifl...
Tetrahydrobiopterin synthesis inhibitors induce nitric oxide synthesis in rat aorta

Abstract I. Incubation of rato aortic rings with tetrahydrobiopterin synthesis inhibitors (NAS or DAHP) significantly decreased contractions to phenylephrine. These two compounds significantly potentiated the vascular hyporeactivity induced by endotoxin. Inhibitors of nitric oxide synthesis (NLA or MLA) restored the contractile responses to this α1-agonist in NAS- or DAHP-treated control rings and abolished the NAS- or DAHP-induced increased hyporeactivity to PE in endotoxin-treated aortic rings. These observations suggest that treatment of isolated blood vessels with BH4 synthesis inhibitors induces the production of NO' synthesis, resulting in turn in a vascular hyporeactivity to PE potentiated in endotoxin-treated preparations.
Spontaneous infiltration of non-cylindrical porosity: Close-packed spheres

Abstract Previous experiments indicated that the contact angles required for spontaneous infiltration of molten metal alloys into particulate ceramic preforms are significantly less than 90°. Analysis of capillarity in pores between packed particles shows the origin of this effect to be in the non-cylindrical curvature of these pore surfaces. A simple geometrical approach for predicting critical contact angles, θ c , for spontaneous infiltration of non-cylindrical pores is presented and applied to the pore structure between closepacked spheres. Although the critical contact angle for entry of the first layer of pores varies with the direction of infiltration, complete spontaneous infiltration of the structure is limited by penetration of the tetrahedral pores, for which θ c = 50.7°.
Effects of modeled optical properties on recovered fluorophore concentration during image-guided fluorescence tomography

In fluorescence molecular tomography, optical measurements at the surface are used with diffusion theory modeling to reconstruct the maps of the fluorophore distribution in the tissue using an iterative error minimization algorithm. While normalizing the fluorescence signal with the excitation signal has been shown to correct for source and detector inconsistencies somewhat, this approach does not always correct for tissue heterogeneities and inaccuracies that are not matched by the forward diffusion model. Using computer simulations and an ultrasound-guided fluorescence tomography (FT) system designed for spatial mapping of Protoporphyrin IX (PpIX), the errors in fluorophore concentration recovery by assignment of incorrect optical properties are analyzed. Using simulations and experiments, white light spectroscopy was used to obtain more accurate tissue properties for forward diffusion model, prior to FT. Using white light spectroscopy the accuracy in FT values improved by 97% on average and the minimal detectable concentration of PpIX with the system was 0.025μg/ml.
The Duration of Civil War Peace Agreements

The focus of this article is civil war peace agreement duration from 1989 to 2005. Recent work by Hartzell and Hoddie (2003, 2007) has argued that power-sharing provisions have a cumulative impact. In other words, the more power-sharing provisions there are built into an agreement, the greater the prospects for peace. Our basic theoretical premise is that power-sharing provisions that are costlier to government and more difficult to implement will decrease the life span of the peace agreement because of government motivations to renegotiate and rebel incentive to strike preemptively before the government does or out of frustration because of delays in implementing costly provisions. In other words, governments will abandon the agreement because it concedes too much or rebels will abandon the agreement because of delays in implementation and/or to move preemptively. We look at three forms of power-sharing provisions: military (integration of rebels into army), territorial (autonomy), and political (shared ...
Development of serum-free media for the growth of human gastrointestinal adenocarcinoma xenografts as primary tissue cultures

The growth-promoting effect of several hormones and growth factors on eight human colon tumor cell lines (SW 48, SW 403, SW 480, SW 620, SW 948, HT29, LS174T and Caco-2) was studied using seven different chemically defined serum-free media [GF3: Chee's essential medium plus insulin, transferrin and selenium; GF3F: GF3 plus fetuin; GF4: GF3 plus linoleic acid/ bovine-serum albumin (BSA); GF5: GF4 plus fetuin, GF5E, GF5 plus EGF; GF5T: GF5 plus triiodothyronine; GF7: GF3 plus EGF, transferrin, insulin, linoleic acid/ BSA, oleic acid/BSA and fetuin]. GF5 appears to be the best serum-free medium as it supported continuous growth of all of the colon tumor cell lines. GF5 also supported growth of five of the seven human colon and stomach tumor xenografts as primary tissue cultures. However, the stomach xenograft cells had a very slow growth rate as compared to the colon xenograft cells in the medium. Cells grown in GF5 retained their tumorigenicity in athymic (nude) mice and characteristic cellular morphology. GF7 was the poorest of all of the serum-free media studied as none of the cell lines or xenografts grew in this medium.
Opioids and central baroreflex control: a site of action in the nucleus tractus solitarius.

Abstract These studies investigated whether the nucleus of the tractus solitarius (NTS) is a central site where opioids modulate baroreceptor reflexes. Microinjections into the NTS of [D-Ala 2 ,MePhe 4 ,Gly-ol 5 ]enkephalin (DAGO) significantly reduced reflex-mediated depressor responses evoked by electrical stimulation of the aortic nerve. Subsequent NTS injections of naloxone restored baroreflexes to control levels. These results demonstrate that the NTS is a central site where exogenously administered opioids can modulate baroreceptor reflexes. NTS injections of naloxone had no effect on baroreflex function, suggesting that tonic activation of opioid receptors at this site plays little or no role in central baroreflex control.
Pore size effects on sintering of Ni/Al2O3 catalysts

Abstract Effects of pore size on sintering kinetics of Ni Al 2 O 3 catalysts have been studied with in situ magnetization and hydrogen chemisorption measurements. Three samples of α-Al 2 O 3 were prepared differing only in pore size distributions, with average pore radii of 4.1, 5.4, and 7.6 nm, respectively. These samples were loaded with 7 wt% nickel using homogeneous deposition. Nickel crystallite size distributions were very narrow at 2- to 2.3-nm radius. Sintering in helium at 500 and 600°C increased crystallite size but decreased accessibility of the nickel surface, due to physical blockage and not electronic effects. Measurements before and after loading showed only small changes in pore size distribution. Initial sintering rates increased by a factor of 4 as pore size doubled. Nickel surface areas followed the decay curve dS dt = −kS n with k increasing by about a factor of 1000 while n remained in the range 7–10. Crystallite size distributions were stable after 20 h but surface blockage occurred for crystallites approaching the pore radii in size with sintering confined to individual pores.
Effects of spatial variability of hydraulic resistance of runoff hydrographs

Abstract The effects of spatial variability of roughness on runoff hydrographs have been investigated for an experimental watershed facility surfaced with butyl rubber or various combinations of butyl rubber covered with gravel. An equivalent uniform roughness is defined in terms of the hydrograph response to identical rainfall excess patterns. Experimental results and simulation studies demonstrated that equivalent uniform roughness does exist for watersheds with nonuniform roughness under certain circumstances. Furthermore if an equivalent uniform roughness exists, it can be estimated by equating the steady-state surface water storage on the hypothetical uniform watershed to that on the nonuniform watershed.
Electronic structure of gonadotropin-releasing hormone (GnRH): a semiempirical study

Abstract GnRH is a peptide hormone, pyroGlu 1 -His 2 -Trp 3 -Ser 4 -Tyr 5 -Gly 6 -Leu 7 -Arg 8 -Pro 9 -Gly 10 -NH 2 . This hormone acts on a specific membrane receptor promoting the release of the gonadotropins, luteinizing hormone and follicle-stimulating hormone. Because of its biological importance, we studied the electronic structure and associated physicochemical properties of this molecule. The polypeptide was modeled according to the propensity of each amino acid to promote an α -helix or a β -sheet, using the method described by Chou and Fasman (Biochemistry 13 (1974) 222–245). In this model His 2 -Trp 3 and Leu 7 are considered α -helix promoters with Φ and Ψ dihedral angles of −57° and −48°, respectively. Ser 4 , Tyr 5 , Gly 6 , Arg 8 and Gly 10 were assigned with Φ and Ψ angles values of −140° and 135°, respectively; pyro-Glu 1 was set similarly to Pro 9 with Φ and Ψ angles values of −65° and 150°, respectively. The a priori structure adopted an inverted “S” shape and was minimized by molecular mechanics and subsequently refined by the semiempirical model PM3. Additionally, the aqueous solvation energy was calculated. The shape was fairly conserved after energy minimization with some changes in Φ and Ψ angles. The aromatic character of His 2 -Trp 3 dipeptide and Tyr 5 showed a double-sided electrostatic potential and the frontier orbitals were located in both rings of Trp 3 making this residue suitable for nucleophilic and electrophilic attacks. The three aromatic residues may have weak but important CH/ π -interactions of GnRH with its receptor. The contribution of the hydroxyl groups of Ser 4 and Tyr 5 and the possibility of Arg 8 protonation was evident by the charge values. The residues pyru-Glu 1 and Pro 9 appears to play a role in structure stabilization along with the pairs formed by His 2 -Trp 3 and Gly 6 -Leu 7 . Tyr 5 aromatic ring displays a double-sided electrostatic potential including the hydroxyl group in a conjugated fashion. The carbonyl group of pyro-Glu 1 and the oxygen of Ser 4 and Tyr 5 are possible candidates to interact with Lys 121 on the GnRH receptor.
Stability of acetylated and superguanidinated chymotrypsinogens.

Abstract Conversion of lysine residues to homoarginine led to protein stabilization as determined earlier by hydrogen isotope exchange ( P. Cupo W. El-Deiry, P. L. Whitney and W. M. Awad, Jr., 1980, J. Biol. Chem.255, 10828–10833 ). In order to see if neutralization of charges on lysine residues affected stability, a homogeneous derivative of chymotrypsinogen was prepared wherein all amino groups were acetylated. Hydrogen isotope exchange studies indicated that the derivative was less stable than the native protein. In addition, highly guanidinated chymotrypsinogen was prepared by first coupling ethylenediamine to carboxyl groups of guanidinated chymotrypsinogen. Thereafter the protein was treated with O-methylisourea to form guanidinoethylamido groups at the ends of carboxyl residues. Acrylamide gel electrophoresis indicated that two products were formed. Hydrogen isotope exchange studies demonstrated that superguanidinated chymotrypsinogen is even less stable than the acetylated derivative. Thus guanidination of residues in addition to lysine does not lead to protein stabilization. The possibility is that such a highly cationic protein causes backbone fluctuations because of repulsion of surface charges.
In the eye of the beholder: Relational and hierarchical structures in conceptualization

Abstract This paper describes the translation from hierarchical structures, operationalized as outlines, to relational structures, operationalized as the maps derived from a multidimensional scaling and cluster analysis procedure. Using a variety of models that represented different assumptions about the relationships within the outline, similarity matrices were derived for a sample outline. The resulting maps were examined to see how well they reflected the outline. The three best reflections are presented here. The ability to translate between hierarchical and relational structures will give program planners and evaluators greater flexibility in both the sources for and the representation of a conceptualization.
Percutaneous transhepatic biliary stenting

Summary For patients in whom endoscopic biliary intervention is not appropriate, the transhepatic route provides ready access to the biliary tree. With careful attention to detail (in particular, the route of the initial access to the ducts) and consistent follow-up, this procedure may have a significant impact on the course of the patient's biliary disease.
In vivo aminoacylation of brome mosaic and barley stripe mosaic virus RNAs

The genomic RNAs of several plant viruses are now known to be able to bind a specific amino acid at their 3′ ends in a tRNA-like manner. Where the nucleotide sequence of the 3′-terminal region is known, it can be folded into an extensively base-paired secondary structure having the essential features of tRNAs1,2. The high degree of nucleotide sequence conservation of the 3′-terminal regions of the four RNAs of the three known bromoviruses3, and the loss of infectivity of brome mosaic virus (BMV) RNA after chemical modification of its 3′ end4, strongly suggest that the tRNA-like structure has a biological function in infection2. To elucidate this it has been important to determine whether viral RNAs are aminoacylated within infected host cells. We studied BMV and barley stripe mosaic virus (BSMV), which belong to very different groups but which have genomic RNAs that are capable of both accepting tyrosine and infecting barley protoplasts. We report here that single-stranded RNAs of both viruses are aminoacylated in vivo, but that the encapsidated RNAs of BMV are not.
Open systems in contact with a ferromagnetic Fermi sea: quantum particle-number fluctuations

Abstract We study the effects of the particle-number fluctuation in small fermionic quantum systems in contact with a completely ferromagnetic Fermi sea in an exact diagonalization approach based on a formalism previously developed by Artacho and Falicov [Phys. Rev. B 47 (1993) 1190]. A symmetry associated with the particle-number fluctuation is identified and used, together with other symmetries of the system, in the projection of the eigenstates and the block diagonalization of the Hamiltonian matrix. A two-site Hubbard model is used as an example to illustrate the implementation of the theory. Physical consequences of the quantum particle-number fluctuation and further applications of the theoretical approach are discussed.
Feedback from Horizontal Cells to Rod Photoreceptors in Vertebrate Retina

Retinal horizontal cells (HCs) provide negative feedback to cones, but, largely because annular illumination fails to evoke a depolarizing response in rods, it is widely believed that there is no feedback from HCs to rods. However, feedback from HCs to cones involves small changes in the calcium current ( I Ca) that do not always generate detectable depolarizing responses. We therefore recorded I Ca directly from rods to test whether they were modulated by feedback from HCs. To circumvent problems presented by overlapping receptive fields of HCs and rods, we manipulated the membrane potential of voltage-clamped HCs while simultaneously recording from rods in a salamander retinal slice preparation. Like HC feedback in cones, hyperpolarizing HCs from −14 to −54, −84, and −104 mV increased the amplitude of I Ca recorded from synaptically connected rods and caused hyperpolarizing shifts in I Ca voltage dependence. These effects were blocked by supplementing the bicarbonate-buffered saline solution with HEPES. In rods lacking light-responsive outer segments, hyperpolarizing neighboring HCs with light caused a negative activation shift and increased the amplitude of I Ca. These changes in I Ca were blocked by HEPES and by inhibiting HC light responses with a glutamate antagonist, indicating that they were caused by HC feedback. These results show that rods, like cones, receive negative feedback from HCs that regulates the amplitude and voltage dependence of I Ca. HC-to-rod feedback counters light-evoked decreases in synaptic output and thus shapes the transmission of rod responses to downstream visual neurons.
Studies on Head/Disc Contact Area Increase During Contact Start/Stop and Continuous Drag Testing of Thin Film Discs

The relationship between friction and surface roughness during start/stop and continuous drag testing of thin film discs and heads was studied. Roughness measurements were made in wear tracks on several types of discs using a stylus profiler. Two methods were used to relate surface topography to the real area of contact. For the first method the roughness data was used to generate Z-height distributions and bearing ratio curves. Using average mean-peak roughness as the height at which the head and disc make contact, the bearing ratio at that height was used as the relative contact area. In the second method, analysis of the highest peaks was used to find the standard deviation of heights and average curvature. From this the contact area was calculated using the Greenwood-Williamson model of elastic contact. Analysis of the contact area vs. coefficient of friction yielded fairly good linear correlation for both methods. Formation of ultra fine wear debris in the wear track of one disc was found to reduce s...
Trichloroethylene accelerates an autoimmune response by Th1 T cell activation in MRL+/+ mice

Trichloroethylene (1,1,2-trichloroethene) is a major environmental contaminant. There is increasing evidence relating exposure to trichloroethylene with autoimmunity. To investigate potential mechanisms, we treated the autoimmune-prone MRL +/+ mice with trichloroethylene in the drinking water at 0, 2.5 or 5.0 mg/ml and sacrificed them at 4, 8 and 22 weeks. As early as 4 weeks of treatment, Western blot analysis showed a dose-dependent increase in the level of trichloroethylene-modified proteins, indicating that a reactive metabolite of trichloroethylene was formed. Significant increases in antinuclear antibodies (ANA) and total serum immunoglobulins were found following 4-8 weeks of trichloroethylene treatment, indicating that trichloroethylene was accelerating an autoimmune response. Investigation into possible mechanisms of this autoimmune response revealed that trichloroethylene treatment dramatically increased the expression of the activation marker CD44 on splenic CD4+ T cells at 4 weeks. In addition, splenic T cells from mice treated for 4 weeks with trichloroethylene secreted more IFN-gamma and less IL-4 than control T cells, consistent of a T-helper type 1 (Th1) type immune or inflammatory response. A specific immune response directed against dichloroacetylated proteins was found at 22 weeks of trichloroethylene treatment. Taken collectively, the results suggest that trichloroethylene treatment accelerated an autoimmune response characteristic of MRL +/+ mice in association with nonspecific activation of Th1 cells. In addition, long-term treatment with trichloroethylene led to the initiation of a trichloroethylene-specific immune response.
Light chain composition of CSF oligoclonal IgG bands in multiple sclerosis and subacute sclerosing penecephalitis

Abstract The light chain composition of MS and SSPE CSF oligoclonal IgG bands was examined using isoelectric focusing and sensitive peroxidase-anteperoxidase (PAP) staining technique specific for gamma heavy chains (γ), kappa light chains (κ), or lambda light chains (λ) and a radioimmunoassay (RIA) for γ, κ, or λ. Many bands in the 7 MS and 4 SSPE CSF examined were monoclonal, staining for either IgG-κ or IgG-λ. By staining, all MS CSF were κ predominant; SSPE CSF were variously κ orλ predominant. RIA confirmed the κ predominance of MS CSF. Three MS and 2 SSPE CSF contained bands staining for λ alone, i.e. free light chains. Analysis of RIA data confirmed these findings in 2 MS cases. The difference in light chain predominance of MS and SSPE CSF may reflect differences in the antigenic target, or the age of patient at the time when band-synthesizing clones are triggered. Six of 7 MS and all 4 SSPE CSF contained oligoclonal bands staining for γ and for both κ and λ, probably representing artifacts of IEF. No predominant immunochemical differences between bands in MS and SSPE were detected.
HDL optimization using timed decision tables

System-level presynthesis refers to the optimization of an input HDL description that produces an optimized HDL description suitable for subsequent synthesis tasks. In this paper, we present optimization of control flow in behavioral HDL descriptions using external Don't Care conditions. The optimizations are carried out using a tabular model of system functionality, called Timed Decision Tables or TDTs. TDT based optimization presented here have been implemented in a program called PUMPKIN. Optimization results from several examples show a reduction of 3-88% in the size of synthesized hardware circuits depending upon the external Don't Care information supplied by the user.
Paper Weight: History's Legacy in the Work of MARY EVANS

Artist Mary Evans has been working in cut paper since the mid-1990s. In her chosen medium, Evans investigates signs and signifiers of the way humans tend to classify certain races and nationalities, particularly in visual terms. Over the course of her career, her work has evolved to reveal the ways in which racism, the history of slavery, and the legacy of the British Empire are embedded in such practices. For over twenty years, Evans has been exploring recurring motifs that resonate not only with her personal biography as a Lagos-born, London-based artist, but also with contemporary identity politics and issues of belonging and alienation. An analysis of Evans’s recent work, including Willow Plate series (2013), Gingerbread (2012), and Held (2012), explicates the ways in which cultural and national ideologies are articulated through an exploration of personal and historical narratives of human experience. Evans’s silhouetted figures evoke racial and sexual stereotypes and thus powerfully communicate humanity’s historical tendency to categorize and prejudge. An investigation of how her early training, experiences abroad, and artist residencies specifically impacted her professional development contextualizes the works. In addition, a comparison of Evans’s work with the well-known oeuvre of Kara Walker highlights striking thematic differences despite intriguing similarities in both form and subject and demonstrates each artist’s unique talents in the medium of cut paper installation.
QCD hard scattering from string/gauge duality

Abstract Conventional superstring amplitudes in flat space exhibits exponential fall off at wide angle in stark contrast to the parton behavior found in QCD power law behavior. Polchinski's and Strasseler's resolution of this conflict via String/Gauge duality is extended to the phenomenologically interesting M-theory model of glueballs and to elucidate the origin of the hard Pomeron.
The Influence of Layer Flock Age on Egg Component Yields and Solids Content

Abstract Two experiments were conducted to determine the influence of layer flock age on egg component yields and solids content of the yolk and albumen. Experiment 1 was conducted on eggs collected during February from six commercial farms with the same strain (Shaver) of birds ranging in age from 26 to 58 weeks and fed the same dietary energy and protein levels. The total and relative amounts of shell, yolk, and albumen were determined using two separation techniques and the total solids were determined for the yolk and albumen. Experiment 2 was conducted in August using four commercial flocks of Shaver hens ranging in age from 29 to 6 2 weeks. The eggs were analyzed as in Experiment 1 using the separation technique that resulted in the lowest coefficient of variation. Results indicated that as layer flock age increases, egg weight, dry shell weight, deformation and percent yolk increased, percent shell, percent albumen and percent albumen solids decreased, and percent yolk solids exhibited no consistent patterns. These differences would result in an approximately 2% increase in dry yolk solids by using eggs from older hens.
Corticospinal tract transection reduces H-reflex circadian rhythm in rats.

Abstract In freely moving rats and monkeys, H-reflex amplitude displays a marked circadian variation without change in background motoneuron tone. In rats, the H-reflex is largest around noon and smallest around midnight. The present study evaluated in rats the effects on this rhythm of calibrated contusions of mid-thoracic spinal cord and mid-thoracic transection of specific spinal cord pathways. In 33 control rats, rhythm amplitude averaged 29.0(±2.6 S.E.)% of H-reflex amplitude. Contusion injuries at T8–9 that destroyed 53–88% of the white matter significantly reduced the rhythm to 18.9(±2.4)% of H-reflex amplitude. Transection of the ipsilateral lateral column, which contains the rubrospinal, vestibulospinal, and reticulospinal tracts, or bilateral transection of the dorsal column ascending tract did not affect rhythm amplitude or phase. In contrast, bilateral transection of the main corticospinal tract significantly reduced the rhythm to 14.7(±6.6)%. These results indicate that the H-reflex circadian rhythm depends in part on descending influence from the brain and that this influence is conveyed by the main corticospinal tract.
Depth dependence of nucleation in implanted polycrystalline silicon films on SiO2

Abstract Crystallization of a 1500 A polycrystalline silicon film self-implanted at an energy of 100 keV and a dose of 2 × 10 15 ions/cm 2 is found to be due to the nucleation of crystallites at or near the top surface. Nucleation is believed to be due to small crystalline regions (clusters) which survive implantation. Such clusters will exist predominantly at the depth corresponding to the least implant damage which, for this implantation-target combination, is at the top surface.
Implementing early visual processing in analog VLSI: light adaptation

A circuit which emulates the functioning of cone photoreceptors in the vertebrate retina has been designed and tested. Cone photoreceptors exhibit a local adaptation to background illumination over many orders of magnitude while retaining a high degree of instantaneous contrast sensitivity. This behavior permits visual discrimination of objects against difficult lighting situations such as bright backgrounds. This effort includes an examination of the trade-offs in various photodetection techniques available to the designer in silicon. Photodetection is followed by separate filter and gain stages which provide the appropriate temporal behavior. The filters and gain are independently tunable to permit extensions in operation to those environments which may fall outside the capability of human vision. The circuit also includes a UV writable floating gate which uses a locally generated error signal to provide cancellation of circuit offsets due to process variability.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Effects of cations and colchicine on the release of prolactin and growth hormone by functional pituitary tumor cells in culture.

Monolayer cultures of the GH3 clone of functional rat pituitary cells have been used to study the short-term effects of cations and colchicine on the release of prolactin (PRL) and growth hormone (GH). Intracellular and extracellular concentrations of the hormones were measured by immunological methods. Increased extracellular concentrations of potassium (50 HIM) enhanced the release of both PRL and GH while the same concentration of sodium had no effect. Reduced or elevated levels of extracellular calcium had no acute (3 hr) effect on hormone release. Similarly, increased extracellular magnesium (10 HIM) did not affect hormone release. High potassium, but not high sodium, calcium or magnesium, had a hormone-releasing effect on cells in which the synthesis of PRL and GH had been stimulated by thyrotropin-releasing hormone or hydrocortisone, respectively. The hormone- releasing effect of high potassium treatment did not occur if the culture medium was low in calcium. Colchicine (5 X 10-6 M ) inhibited acut...
Effect of compression loads on the solder joint reliability of flip chip BGA packages

Rising power dissipation requirements in modern semiconductor devices have created a need for high performance thermal solutions. These thermal solutions require increasing amounts of compression loading to ensure good conductance of thermal interface materials and retention of massive heat sinks in shock conditions. The impact of these loads on the reliability of the package solder joints has typically not been considered in both finite-element-based and statistical-based assessment methodologies for fatigue of solder joints. The goal of this work is to provide an understanding of the effects of these loads and provide new methods to characterize the limits of these loads for reliable operation throughout the life of the component. This paper discusses the critical impact of the thermal compression loads on solder joint reliability for both fatigue and creep. In this work, a new experimental test method is described. This method utilizes a fixture that simulates the thermal solution load during life testing. The fixture design allows the load and support conditions to be varied and their effects studied. Testing of surface mounted components has been conducted and implications to the standard statistical life prediction methods are discussed. In addition, finite-element-based modeling assessments for the loading conditions have been performed. The analysis shows the impact of the thermal compression load on discrete solder joints for both thermal cycling and long duration high temperature (bake) testing. The implications of compression loading to analytical and statistical life prediction methods are discussed. Based on the experimental and modeling data, load and support boundary condition limits are proposed as the best way to prevent solder joint failures.
Solar Power for Autonomous Floats

Abstract Advances in low-power instrumentation and communications now often make energy storage the limiting factor for long-term autonomous oceanographic measurements. Recent advances in photovoltaic cells, with efficiencies now close to 30%, make solar power potentially viable even for vehicles such as floats that only surface intermittently. A simple application, the development of a solar-powered Argos recovery beacon, is described here to illustrate the technology. The 65-cm2 solar array, submersible to at least 750 dbar, powers an Argos beacon. Tests indicate that with minor improvements the beacon will run indefinitely at any latitude equatorward of about 50°. Scaling up this design to current operational profiling floats, each profile could easily be powered by a few hours of solar charging, a shorter time than is currently being used for Argos data communications.
A Test of Philopatry by Common Musk Turtles

We tested philopatry by common musk turtles Sternotherus odoratus in a Virginia lake for 9 wk during summer 2003. Using unbaited crab pots, 10 trapping sites were established in the littoral zone around the lake perimeter and pots were sampled daily, yielding 560 turtle captures. Musk turtles trapped at the two sites separated by the greatest distance (1.1 km) were marked and released at the opposite site; turtles captured at the eight sites in-between were marked and released at the capture site. Of 287 captures of turtles released at their capture site, 57 were recaptured and 43 of these were at the original capture site. Of 140 captures of turtles displaced 1.1 km, 76 were recaptured and 15 of these were turtles that returned to their site of original capture. Turtles moved significantly more once they had been displaced, and males moved more frequently, but not over longer distances than females. These data indicate that S. odoratus is capable of homing and that site fidelity is exhibited by both male and female turtles. In a lake where the ratio of male:female turtles is approximately 1:1, the occurrence of philopatry is consistent with turtles having discrete home ranges.
Power, Knowledge, and Environmental History in the Middle East and North Africa

To consider in what ways incorporating the emerging field of environmental history into studies of the Middle East challenges our views of the past and/or present, it is necessary first to take stock of our mainstream notions of the environment in the Middle East and North Africa (MENA) and how we think it has changed over the last several thousand years. The most common received wisdom about the environment in the MENA is that it is an arid, marginal environment, in many places a wasteland degraded by overgrazing and deforestation for hundreds if not thousands of years. The local populations, especially nomads and small farmers, are frequently blamed for the alleged environmental ruin. Born in large part of Western imperialism in the region, this environmental imaginary of the MENA has been uncritically adopted by the majority of postindependence ruling elites as well as development agencies.
Psychopharmacology of conduct disorder: current progress and future directions

Behavioural manifestations of conduct disorder (CD) among children and adolescents are one of the most common referrals to community psychiatrists. Patients with CD are difficult to treat. The patterns of maladaptive behaviours they exhibit are diverse and can vary as a function of age and gender. Although different pharmacological interventions have been reported as potentially promising options in the treatment of CD, no medication has yet received a formal approval from the licensure authorities, either in the US or Europe. This article reviews efficacy results and associated adverse effects from selected clinical trials that have the strongest outcome evidence for the treatment of CD in children and adolescents. Critical issues in the effectiveness of the evidence-based pharmacotherapy for CD are raised and future directions of the psychopharmacology of CD are examined.
Role of Emotion in Cognitive-Behavior Therapy

In this article, we suggest that the long-term effectiveness of cognitive-behavior therapy (CBT) may be enhanced by going beyond symptoms at the cognitive level (i.e., intellectual meanings) and expanding therapeutic focus to the underlying, implicit emotional meanings. Following a discussion of the state-of-the-art view on emotion in CBT, we present empirical, theoretical, and clinical evidence from cognitive science, experimental psychology, and cognitive neuroscience pointing to the distinction between cognitive and emotional domains of information processing. We discuss the role of affective processes in reorganizing emotional meanings and consider how CBT therapists can use in-session emotional processing to facilitate clinical change.
Nonparametric decentralized sequential detection

We consider a decentralized sequential detection problem with a set of sensors and a fusion center. Each sensor receives information from inputs and possibly other sensors at discrete times and transmits summary information to a fusion center which processes the summary information by performing a sequential test to make a decision on one of two hypotheses. The work discussed differs from previous work by Veervalli, Basar and Poor (1993) in that the conditional densities given each hypothesis are unknown. Information about making good decisions is learned from observing real data and employing reinforcement learning procedures.
Scalable encryption for multimedia content access control

Traditional cryptography systems treat every portion of a message (a video, an image, or an audio) equally and encrypt the entire message as a whole. As a result, those security systems often have only two states: access authorization and access denial. To facilitate multi-level access control with interoperability, scalable security mechanism is needed. Further, the availability of varying network bandwidth and diverse receiver device capabilities demand scalable and flexible approaches that are capable of adapting to changing network conditions as well as device capabilities. In this paper, we describe a multimedia encryption scheme that supports scalability. One desirable feature of the proposed scheme is its simplicity and flexibility in supporting scalable content access control.
Age-associated memory loss: initial neuropsychological and cerebral metabolic findings of a longitudinal study.

To determine the relationships between clinical and brain function in persons with a familial risk for Alzheimer's disease, the authors assessed subjective and objective cognitive abilities, mood state, and cerebral glucose metabolism (using positron emission tomography) in 43 persons with age-associated memory impairment, with and without first-degree relatives with a clinical diagnosis of Alzheimer's disease. Subjective complaints of memory loss, mood state ratings, and objective memory measures were similar in persons with a family history of Alzheimer's disease (n = 29) compared to those without such a history (n = 14). Metabolic ratios in the frontal regions correlated with a decrease in a specific type of subjective memory complaint (mnemonics usage; p < .001) and some mood state ratings. These results indicate that parietal and temporal hypometabolism is not evident in persons with mild age-related memory complaints, even when such subjects have a familial risk for Alzheimer's disease. Moreover, self-reports of mnemonics usage may be sensitive indicators of decreased frontal lobe function. Longitudinal study will determine whether such clinical and metabolic measures will predict eventual disease progression.
Processes of Place Attachment: An Interactional Framework

How do people form place attachments through interaction with others and with places over time? I propose that there are seven distinct processes through which people form bonds with places. This framework was developed from the analysis of 104 depth interviews conducted in California and Colorado, newspaper and magazine columns and letters, memoirs, and first person essays. This framework proposes that seven distinct processes interact at the individual, group, and cultural level to shape place attachment. Each of the seven processes has a unique nature and develops differently over time and space.
Variation of photoperiod response in moss gametangial formation

Photoperiod duration has been shown to induce reproduction in angiosperms and liverworts. In general, moss gametangial production has been considered non-respondent to photoperiod, yet has been insufficiently tested. Here, we tested the response of gametangial formation to day length cues in California populations of Pohlia nutans using controlled light levels and variable day length treatments. Surprisingly, we found that gametangia induction in these P. nutans populations responded to changes in day lengths (long-day to short-day) rather than constant short- or long-day photoperiod regimes, as has been previously reported in a few moss species. We discuss our results with respect to photoperiod induction of gametangia in mosses.
Self-Determination During Adolescence A Developmental Perspective

Adolescence, the tumultuous period from dependent childhood to independent or interdependent adulthood, is a critical time for the development and expression of self-determination. An instructional emphasis and support system for self-determination is particularly important for youth with disabilities. Adolescent development, embracing identity exploration and learned independence in youth, leads to self-awareness, one of the building blocks for self-determination. Successful transition to adulthood, fostered by one's ability to set and reach goals through decision making, is a necessary outcome of self-determination. Students' participation in their educational plans provides an important vehicle for the development and expression of self-determination in students with and without disabilities. A model for self-determination is presented that incorporates components of the skills and knowledge necessary for adolescents to realize their identities. Interventions aimed at promoting self-determination in yo...
Characterization of the interactions between synthetic nematic LCs and model cell membranes

Differential scanning calorimetry (DSC) was used to characterize interactions of synthetic LCs, 4‐pentyl‐4′‐cyanobiphenyl (5CB) and TL205 (a mixture of cyclohexane‐fluorinated biphenyls and fluorinated terphenyls) with simple mimics of cell membranes. The investigation was motivated by reports that living cells can be placed into contact with TL205 without apparent toxicity, whereas contact of cells with 5CB leads to cell death. The tendency was examined for 5CB and TL205 to spontaneously partition into and influence the organization for model cell membranes composed of phospholipids. Upon contact of an aqueous dispersion of DPPC liposomes with neat LC for 4 h, 5CB partitioned into the liposomes at a weight ratio of 5:1 DPPC:5CB, whereas TL205 partitioned at a ratio of 310:1 DPPC:TL205. DSC endotherms indicated that the 5CB spontaneously partitioned into the liposomes was far more perturbing than TL205. DSC endotherms of DPPC bilayers containing the same concentration of either 5CB or TL205 also revealed ...
Theory of antiferromagnetically coupled magnetic recording media

A theoretical overview of antiferromagnetically coupled media (AFC media) is presented for the case where the AFC medium has two ferromagnetic films that are coupled antiferromagnetically via a thin polarization layer. Attention is focused on AFC-slave media where the top layer governs the remanent magnetization. It is demonstrated that such media behave like an effectively thin single layer magnetic recording medium in terms of improved pulse width, while the magnetic stability of AFC grains is governed by the thicker top layer.
The Disequilibrium Theory of Changes in Total Economic Activity

. It is widely taught that national product departs from, but returns toward, an “equilibrium” level. Return from sub-equilibrium, it is believed, involves depleting inventories; return from super-equilibrium involves building them up; in both cases, at a diminishing rate. Observable product and observable aggregate stocks of goods, however, usually rise and fall together; they do not change in opposite directions, as implied. Stocks are not large enough to support the supposed depletion at low income levels. “Intended” changes contrary to the actual changes are not documented. The disequilibrium theory does not promote understanding of historical cycles in product.
Group B Streptococcal Infection Early Onset Disease Controversies in Prevention Guidelines, and Management Strategies for the Neonate

Group B streptococcus (GBS) has been a major pathogen that is particularly devastating to the newborn for more than two decades. Initial guidelines were promoted by the AAP in 1992 to help deal with this organism, but these recommendations were poorly accepted and not widely used. In 1996-1997 the AAP, CDC, and ACOG created new guidelines for the management of the mother and infant at risk for GBS. Though usually in agreement, these three sets of recommendations still have some differences that may be confusing to the pediatrician. This paper looks at the acquisition, intrapartum treatment, and postnatal management of GBS, along with some of the controversies associated with the management of this disease.
Lichen Communities as Indicators of Forest Health

ently fuzzy concept, even when applied to ourselves. And forests (and other ecosystems) are fuzzier than organisms, being weakly bounded and loosely organized. So the concept of "forest health" can seem hopelessly vague. Nevertheless, in extreme cases anyone can spot a "sick" forest. Despite forest health being a fuzzy concept, people want healthy forests and expect resource management agencies to monitor them. The concept of ecosystem health is contentious not only because it is fuzzy, but also because it embodies societal values and preferences (Lackey 1998). The more that people disagree on these values, the more contentious the concept of ecosystem health.
Diet and exercise during cardiology fellowship training: practicing what we preach.

Cardiologists and cardiology fellows routinely recommend lifestyle modifications for patients with chronic cardiovascular conditions, such as coronary heart disease and congestive heart failure. In particular, exercise and eating a healthy diet comprise the backbone of recommendations provided to