cssi/SciSciGPT-SciSciNet huggingface dataset:
Erythrocyte membrane fractions contain free barbed filament ends despite sufficient concentrations of retained capper(s) to prevent barbed end growth.

Many cellular functions depend on rapid cytoskeletal rearrangements localized to specific cytoplasmic domains. Tight regulation of the submembranous microfilament network is accomplished in large part in erythrocytes and granulocytes by actin binding proteins that cap the fast-growing barbed filament ends. Study of this dynamic system is necessarily hampered by the confounding perturbations of cell lysis and dilution. In this paper, we characterize the functional properties of the membrane-associated spectrin-actin complex from human erythrocytes as it exists after hypotonic lysis. Purified spectrin-actin “seeds” extracted from erythrocyte membranes effectively nucleated actin elongation from their barbed ends. However, polymerization from spectrin-actin complexes associated with the membrane fraction prematurely slowed despite the presence of G-actin in great excess of the critical monomer concentration. The addition of cytochalasin B decreased (rather than augmented) the slowing of elongation attributable to the membrane fraction, indicating that capping of barbed filament ends (not monomer sequestration) was the major mechanism underlying this effect. The paradoxical implication of our findings is that, despite the presence of excess capper(s) in the membrane fraction, the membrane-associated spectrin-actin seeds were not capped until after dilution into physiological ionic strength buffer containing monomeric actin. Furthermore, by comparing the degrees of contamination of the extracted and membrane-associated spectrin-actin preparations, it appeared that recognized capping proteins (including gelsolin and capping protein β2) were not the predominant cappers found in the membrane pellet after hypotonic lysis. We hypothesize that the barbed ends of membrane-associated spectrin-actin complexes, while not excluding actin monomers, may be selectively inaccessible to certain cappers (perhaps simply as the result of steric hindrance). Growth from such complexes in vivo could be limited by the availability of polymerization-competent G-actin. Cell Motil. Cytoskeleton 43:10–22, 1999. © 1999 Wiley-Liss, Inc.
A classifying invariant of knots, the knot quandle

Abstract The two operations of conjugation in a group, x▷y=y -1 xy and x▷ -1 y=yxy -1 satisfy certain identities. A set with two operations satisfying these identities is called a quandle. The Wirtinger presentation of the knot group involves only relations of the form y -1 xy = z and so may be construed as presenting a quandle rather than a group. This quandle, called the knot quandle, is not only an invariant of the knot, but in fact a classifying invariant of the knot.
Catalytic performance and characterization of VO2+-exchanged titania-pillared clays for selective catalytic reduction of nitric oxide with ammonia

VO2+ ion-exchanged TiO2-pillared clays (VO–TiO2-PILC) were investigated for selective catalytic reduction of nitric oxide by ammonia in the presence of oxygen. They were also characterized for surface area and pore size distribution and by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electron spin resonance (ESR), and Fourier transform infrared (FTIR) spectroscopy. It was found that VO–TiO2-PILC catalysts were highly active for the selective catalytic reduction (SCR) reaction. The maximum activity was obtained with 2.1–3.5 wt% vanadium, which was close to or slightly higher than the activity of the commercial V2O5+WO3/TiO2 catalyst. The VO–TiO2-PILC catalysts were also resistant to water vapor and sulfur dioxide at high temperatures (>350°C). XRD patterns of VO–TiO2-PILC were similar to that of TiO2-PILC, showing no peaks due to vanadium oxides, even when the vanadium content reached 13.2 wt%. XPS and ESR spectra indicated that vanadium was present mainly as the +5 valence form (probably as V2O5) on the fresh catalysts, but was partially reduced to the +4 form (VO2+) after being heated at 300°C in He. The FTIR spectra of the adsorbed NO+O2 suggested that vanadium oxides were anchored directly on the titania pillars of the catalysts. NH3 molecules adsorbed on the Bronsted acid and Lewis acid sites to form, respectively, NH+4 ions and coordinated NH3 species. These NH3 adspecies were active in reaction with NO and NO+O2. The Bronsted acidity increased with increasing vanadium content, which was consistent with an increase in the SCR activity for low temperatures (e.g., 200°C). By comparison, the adsorption of NOx (x=1, 2) on the catalysts was very weak, especially under reaction conditions. The present results indicate that the reaction path for NO reduction by NH3 on VO–TiO2-PILC is similar to that on V2O5/TiO2; i.e., N2 originates mainly from the reaction between gaseous or weakly adsorbed NO and NH3 adspecies.
Schizophrenic performance on the Halstead-Reitan battery

Compared Halstead-Reitan Battery scores of hospitalized male schizophrenics with scores of normals and brain-damaged Ss to determine performance patterns that differentiate the groups. Schizophrenics performed less well than normals on the Categories, TPT-Memory, and TPT-Location subtests and better than brain-damaged Ss on all subtests except Categories. In general, the effects of medication produced nonsignificant results.
Top-down signals are needed for object completion in the human visual cortex

Objects are often partially occluded during natural viewing conditions. Therefore, visual recognition requires object completion mechanisms capable of extrapolating from partial information to infer the identity of objects. Here we combine psychophysics, theoretical modeling and neurophysiological recordings to further our understanding of the computations involved in object completion. We record neurophysiological activity from subjects with intractable epilepsy who were implanted with electrodes to localize their seizure onset focus. We recorded intracranial field potentials from areas in the temporal lobe including inferior temporal cortex and the fusiform gyrus among other areas. Subjects were presented with brief flashes (150 ms) of objects viewed through small bubbles that only partially revealed the object. Subjects performed a five-alternative forced choice categorization task. Consistent with previous psychophysical studies, recognition from partial information led to longer reaction times. At the physiological levels we observed that electrodes in visual cortex maintained their visual selectivity in response to images containing only a small fraction of object information. The responses to the partially occluded images were smaller in amplitude and showed significantly longer latencies. Furthermore, physiological responses correlated with the subjects' performance on a trial-by-trial basis. We conjecture that these longer latencies reflect indirect evidence for a requirement for enhanced processing, possibly through top-down signals, of occluded objects. Consistent with this hypothesis, we consider a purely bottom-up model of object recognition and the effect of adding top-down signals to this feedforward model. Simulating the responses of the model to the same images used in the physiology and psychophysics, we show that top-down signals improve recognition performance under occlusion conditions.
Oriented thin films of YBaCu(F)O with high Tc and Jc prepared by electron beam multilayer evaporation

Thin films of YBaCu(F)O were deposited on SrTiO3(100) substrates by multilayer deposition from three electron guns containing Y, BaF2, and Cu under a pressure of 5×10−5 Torr of O2. The films were later annealed in a separate chamber under a flowing O2‐H2O atmosphere. X‐ray diffraction studies reveal that the resulting structure is highly oriented with the a axis perpendicular to the substrate. Scanning electron micrographs show a morphology consisting of an array of orthogonal, interconnecting bars with well‐developed junctions. High‐resolution electron microscopy and electron diffraction patterns show that these junctions are atomically abrupt and that the associated c axes are mutually perpendicular. These epitaxial films show a sharp resistive transition with Tc(R=0) as high as 90 K. The zero field critical current density, determined from magnetization measurements, is 2.9×106 A/cm2 at 4.2 K and 5.0×104 A/cm2 at 77 K.
Sulfhydryl inhibitors and enzyme-substrate interactions of carbamyl phosphate synthetase

Abstract 1. 1. The indispensable cofactor for carbamyl phosphate synthetase (ATP: carbamate phosphotransferase (dephosphorylating), EC 2.7.2.5), N- acetyl- l -glutamate , markedly accelerates inactivation of this enzyme by the disulfide 5,5′-dithiobis(2,2′-nitrobenzoate) (DTNB). This effect has been used to examine the interaction of the enzyme with its different substrates and cofactors. The following results have been obtained. 2. 2. ATP in the presence of Mg 2+ is the only substrate to protect against the inactivation. This protection is considerably enhanced if K 2+ is present. HCO 3 − augments the protective effect of ATP and K + , but provides no protection by itself. ADP does not protect against the inactivation. 3. 3. Mg 2+ has been found to increased the rate of inactivation. This effect is particularly marked when acetyl glutamate is present. In the absence of Mg 2+ , the enzyme appears to bind acetyl glutamate at two sites, the second of which is detectable only at high concentrations of acetyl glutamate. Furthermore, inactivation is much slower at all except high levels of cofactor. In contrast, when Mg 2+ is present, the rate of inactivation is much greater, and the second binding site for acetyl glutamate is not detectable. 4. 4. The significance of these findings for the enzymatic reaction has been tested by determining the K m for acetyl glutamate in solutions containing either a slight excess of ATP over Mg 2+ , or a large excess of Mg 2+ over ATP. When unbound Mg 2+ is low, the K m for acetyl glutamate is doubled in value, and the highest levels of acetyl glutamate produce an inhibition of the reaction. When the level of free Mg 2+ is high, there is a lower K m for acetyl glutamate, and no inhibition by acetyl glutamate. If the inhibitory effects of high acetyl glutamate concentration in the plot with low Mg 2+ concentration are ignored, the extrapolated maximum velocity is identical in both cases. 5. 5. None of the other substrates of the enzyme produce any significant effect upon the inactivation. 6. 6. The inactivation of the enzyme by organic mercurials, which is reduced instead of increased by acetyl glutamate, has been reinvestigate in the light of the above results. Mg 2+ reduces the protection by acetyl glutamate, but does not reduce inactivation in the absence of cofractor. Comparison of protection by acetyl glutamate against a variety of organic mercurials has revealed that the cofractor protects against mercurials in a manner which is independent of the nature of the organic portion of the inhibitor.
Inflammatory carcinoma of the breast: treatment results on 107 patients

Abstract From 1958 to 1985, 107 patients with a clinical and/or histopathologic diagnosis of non-metastatic inflammatory breast cancer received radiotherapy as all or part of initial treatment. Therapy included definitive irradiation alone in 31 patients, irradiation with mastectomy in 16 patients, irradiation and combination chemotherapy in 23 patients, and irradiation with chemotherapy and surgery in 37 patients. Survivors have a median follow-up of 30 months. Overall median relapse-free survival (RFS) was 12 months (12% at 5 years). Local control and relapse-free survival were significantly improved for patients receiving surgery as part of initial treatment: 19% (10/52) of operated patients experienced locoregional failure vs. 70% (37/53) not operated (p
Conical emission by 2-ps excitation of potassium vapor

Conical emission, redshifted from the atomic resonance, is observed when a ∼2-ps laser beam, blueshifted from resonance, propagates through potassium vapor. In contrast, no cone is visible when a 150-fs pulse is used. The 2-ps-pulse-induced cone has a unique, small, angular spread of Δθ/θ≈0.1, compared with Δθ/θ≈0.3 from other pulsed experiments, which used 25-ps–5-ns-excitation pulses. In addition, the fraction of the 2-ps-pulse power emitted in the cone reached 7.5%, far exceeding this fraction from the longer-pulse experiments. An additional, unexpected result is that the spectral width of the laser pulse is narrower, without significant intensity loss, after propagation through the vapor. The vapor densities and laser detunings that yield cones in the present experiment are similar to those from the longer-pulse experiments. Although the 2-ps-pulse spectrum partially overlaps the resonance, the cone spectrum and cone angles versus density and laser detuning are similar to those previously reported for nanosecond pulses. The fourth (blue-detuned) wave required for satisfying four-wave mixing is absent, again equivalent to what is observed in the nanosecond experiments. The physical origin of cone emission by pulsed excitation of atomic vapors is still largely unknown, and this high efficiency and narrow angular spread of a spectrally broad cone further contradicts existing models, perhaps ultimately providing a clue to a correct explanation.
Visual detection of particulates in processed meat products by x ray

A test has been run to study the efficacy of detecting particulate contaminants in processed meat samples by manual observation of line-scanned x-ray images. Six hundred processed product samples arriving over a 3 month period at a national USDA-FSIS laboratory were scanned at 230 cm2sec with 0.5 X 0.5 mm resolution, using 50 KV, 13 ma excitation, with digital interfacing and image correction. Images were inspected off-line, using interactive image enhancement. Forty percent of the samples were spiked, blind to the analyst, in order to establish the manual recognition rate as a function of sample thickness [1 - 10 cm] and texture of the x-ray image [smooth/textured], as well as spike composition [wood/bone/glass], size [1 - 4 mm] and shape [splinter/round]. The results have been analyzed using maximum likelihood logistic regression. In meat packages less than 6 cm thick, 2 mm bone chips are easily recognized, 1 mm glass splinters with some difficulty, while wood is generally missed even at 4 mm. Operational feasibility in a time-constrained setting has bee confirmed. One half percent of the samples arriving from the field contained bone slivers > 1 cm long, one half percent contained metallic material, while 4% contained particulates exceeding 3.2 mm in size. All of the latter appeared to be bone fragments.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
uPAR and cathepsin B-mediated compartmentalization of JNK regulates the migration of glioma-initiating cells.

In the present study, we investigated the effect of simultaneous downregulation of uPAR and cathepsin B (pUC), alone or in combination with radiation, on JNK–MAPK signaling pathway in regulating the migration of non-GICs (glioma-initiating cells) and GICs. The increase in the expression of p-JNK with pUC treatment was mostly localized to nucleus whereas increase in the expression of p-JNK with radiation and overexpression of uPAR and cathepsin B was confined to cytoplasm of the cells. Depletion of cytosolic p-JNK with pUC treatment inhibited migration by downregulating the expression of the adapter proteins of the focal adhesion complex. We also observed that knockdown of uPAR and cathepsin B regulated the Ras–Pak-1 pathway to induce the translocation of p-JNK from cytosol to nucleus. In control cells, Pak-1 served as a functional inhibitor for MEKK-1, which inhibits the complex formation of MEKK-1 and p-JNK and thus inhibits the translocation of this complex into nucleus. Hence, we conclude that glioma cells utilize the availability of cytosolic p-JNK in driving the cells towards migration. Finally, treating the cells with pUC alone or in combination with radiation induced the translocation of the MEKK-1-p-JNK complex from cytosol to nucleus, thereby inhibiting the migration of glioma cells.
Catalytic hydrodesulfurization and hydrodechlorination of chloroethyl ethyl sulfide

Abstract Catalytic hydrodesulfurization (HDS) and hydrodechlorination (HDC) of chloroethyl ethyl sulfide (CEES) is carried out over a Ni–Mo/γ-Al2O3 catalyst and Ni and/or Mo supported on active carbon (AC) catalysts. The reactions are as follows: (i) C 2 H 5 – S – C 2 H 4 Cl + H 2 →2 C 2 H 4 + HCl + H 2 S (ii) C 2 H 5 – S – C 2 H 4 Cl +3 H 2 →2 C 2 H 6 + HCl + H 2 S At 300°C and 0.1 MPa, complete conversion of CEES is achieved in a fixed bed microreactor over Ni–Mo/γ-Al2O3 for 100 h with gas molar composition of H2 : CEES : He = 10 : 0.33 : 89.7 and 24,000 cm3/h/g·cat space velocity. The reaction is 98.0% selective to pure hydrocarbons (ethylene and ethane; Reaction (i) and (ii)) and 2% to ethyl mercaptan on Ni–Mo/γ-Al2O3. Over Ni–Mo/AC, the reaction is more selective toward pure hydrocarbons with >99.5% selectivity. The activity order converting CEES to pure hydrocarbons at 300°C is Ni–Mo/AC > Ni–Mo/γ-Al2O3 > Mo/AC > Ni/AC. For all catalysts, the concentration of chlorinated hydrocarbon (chloroethane) is much less than the concentration of sulfur-containing compounds (diethyl sulfide [DES] and ethyl mercaptan) in the product stream, suggesting that hydrodechlorination (HDC) is faster than hydrodesulfurization (HDS) of CEES. Two sulfur-containing compounds — 1,2 bis(ethylthio) ethane and 1,4 dithiane — are detected at short residence times. This indicates the reaction pathway is more complicated than simple HDS and/or HDC reactions.
Combined far‐ield operators in electromagnetic inverse scattering theory

We consider the inverse scattering problem of determining the shape of a perfect conductor D from a knowledge of the scattered electromagnetic wave generated by a time-harmonic plane wave incident upon D. By using polarization effects we establish the validity of the linear sampling method for solving this problem that is valid for all positive values of the wave number. We also show that it suffices to consider incident directions and observation angles that are restricted to a limited aperture. Copyright © 2003 John Wiley & Sons, Ltd.
Swimming muscle helps warm the brain of lamnid sharks

Lamnid sharks are known to have warm red muscle and warm brains. We describe a large vein in lamnid sharks that provides a route for transfer of warm blood from the red muscle to the central nervous system. This ‘red muscle vein’ runs longitudinally in the red muscle and is valved to direct blood flow anteriorly. It joins the myelonal vein in the neural canal, thus providing a route for blood flow from the red muscle to the brain. Temperature profiles along the neural canal of freshly caught mako sharks show that warm blood enters the myelonal vein from the red muscle vein. Experiments with heat generation by model brains indicate that the metabolic heat produced by the brain is probably not sufficient to cause the temperature elevations observed. Metabolic heat imported from the red swimming muscle may be a valuable addition to the heat budget of the head.
On ageing viscoelastic materials

Abstract C onstitutive equations for ageing viscoelastic materials are formulated as differential equations with variable coefficients. Particular attention is devoted to the second order equation; the creep function is derived and asymptotic behaviour is studied. Comparison is made with commonly accepted expressions for creep functions of concrete. Extension to nonlinear behaviour is discussed.
Meat Mutagens and Risk of Distal Colon Adenoma in a Cohort of U.S. Men

Cooking meats at high temperatures and for long duration produces heterocyclic amines and other mutagens. These meat-derived mutagenic compounds have been hypothesized to increase risk of colorectal neoplasia, but prospective data are unavailable. We examined the association between intakes of the heterocyclic amines 2-amino-3,8-dimethylimidazo[4,5,-f]quinoxaline (MeIQx), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-3,4,8-trimethylimidazo[4,5,-f]quinoxaline (DiMeIQx), and meat-derived mutagenicity (MDM) and risk of distal colon adenoma using a cooking method questionnaire administered in 1996 in the Health Professionals Follow-up Study cohort. Between 1996 and 2002, 581 distal colon adenoma cases were identified. Higher intake of MDM was marginally associated with increased risk of distal adenoma [fourth versus lowest quintile: odds ratio (OR), 1.39; 95% confidence interval (95% CI), 1.05-1.84; highest versus lowest quintile: OR, 1.29; 95% CI, 0.97-1.72; P(trend) = 0.08]. Adjusting for total red meat or processed meat intake did not explain those associations. Our data also suggested a positive association between higher MeIQx (highest versus lowest quintile: OR, 1.28; 95% CI, 0.95-1.71; P(trend) = 0.22) and risk of adenoma, but this association was attenuated after adjusting for processed meat intake. DiMeIQx and PhIP did not seem to be associated with risk of adenoma. In conclusion, higher consumption of mutagens from meats cooked at higher temperature and longer duration may be associated with higher risk of distal colon adenoma independent of overall meat intake. Because mutagens other than heterocyclic amines also contribute to MDM, our results suggest that mutagens other than heterocyclic amines in cooked meats may also play a role in increasing the risk of distal adenoma.
Upon Which Much Depends

Lying in bed before turning off the light I stare up at it, that thin rod of glass in the ceiling sprinkler. Such a simple idea, that pillar of glass: left undisturbed it plugs the sprinkler; at high temperature it shatters, releasing a torrent of water. So simple and yet upon which much depends, like the red wheelbarrow of William Carlos Williams, except water is unlikely to ever glaze its surface. High up beyond my reach, that piece of glass might as well be a poem tall and thin designed to shatter when it is needed the most to unlock a fresh perspective. J Med Humanit (2012) 33:55–56 DOI 10.1007/s10912-011-9165-1
Damped oscillations in a Bingham plastic fluid

Abstract Stokes' second problem, the propagation and damping of waves into a semi-infinite fluid generated by harmonic oscillations of a flat pate on the surface, is solved for the simple Bingham Theological constitutive model. The solution reveals the existence of “windows” in the distance-time-stress space in which shearing is possible whereas outside these restricted regions no shearing can occur. Within these restricted regions the wave forms developed are exponentially damped, traveling waves which propagate from the excitation plane into the fluid and disappear along definitely prescribed boundaries determined by the yield condition. The most significant consequence of the existence of these “windows” of shear is that even very small yield stresses will radically modify the induced velocity wave patterns from that which would be expected based upon the classical Newtonian fluid solution of Stokes’ second problem. At least in this physical setting, it is not necessary for shear to occur globally for ...
Telomerase at the center of collapsing glomerulopathy

Collapsing glomerulopathy, the classic kidney lesion in HIV-associated nephropathy, is characterized by the closure of glomerular capillary loops and epithelial cell proliferation. A new study shows that upregulation of TERT, the reverse transcriptase component of telomerase, in podocytes, the key filtration cells in the kidney, plays a major part in the development of this condition by activating Wnt signaling (pages 111–119).
Importance of classical diffusion in NMR studies of water in biological cells

Nuclear-magnetic-resonance measurements of the proton-spin relaxation for water in biological cells are known to exhibit a multiexponential decay. A theory, based on the diffusion equation using the bulk diffusivity of water, is developed to explain this phenomenon. It is shown that multiexponential decay arises simply as a consequence of an eigenvalue problem associated with the size and shape of the cell and that this multiexponential decay can only be observed for samples whose size is of the order of a biological cell. As an example, the theory is applied to a previously published data for rat gastronemius cells. Excellent agreement is obtained, and furthermore, the size of the cell is calculated by fitting the theory to the experiment.
Experimental demyelination produced by the A59 strain of mouse hepatitis virus

Intracerebral inoculation of 4- to 6-week-old C57BL/6 mice with the A59 strain of mouse hepatitis virus (MHV), a murine coronavirus, produced biphasic disease. Acute hepatitis and mild meningoencephalitis were followed by subacute spastic paralysis with demyelinating lesions in the brain and spinal cord as determined by Eponembedded toluidine-blue-stained sections and by electronmicroscopy. MHV-A59 was cultured by plaque assay from the blood, brain, spinal cord, and liver of infected mice during the acute phase, but not in the chronic stage. MHV-A59 antigen was detected by immunofluorescence (IF) until 3 months postinfection (PI). Serum anti-MHV-A59 antibodies were detected from 7 days to 5 months PI. The induction of demyelination by MHV-A59 provides a suitable system to study virus-induced demyelination further.
Effects of monocular deprivation on the cat's geniculate neurons projecting to both areas 17 and 18

When a kitten is reared with one eyelid sutured closed, there are profound changes in the developing visual system. In the lateral geniculate nucleus, the neurons in the laminae innervated by the deprived eye are smaller than normal, and some of these neurons may lose connections with the visual cortex. In the present study a variety of double label retrograde transport methods were used to define the effects of monocular deprivation on cortical projections of geniculate neurons. One marker was injected into area 17 and the other was injected into area 18. Neurons projecting to area 17 are on average 16.4% smaller than those in the nondeprived laminae. The neurons that normally would project to both areas 17 and 18 by an axon that branches are the most severely affected by monocular deprivation. These cells are nearly 40% smaller than their counterparts in the nondeprived laminae, and many of the neurons appear to lose their projection to one of the cortical areas. These neurons may be at a distinct disadvantage, since they must compete with neurons from the nondeprived laminae for a considerable amount of cortical territory in two different cortical areas. This competition may be so severe that some of the neurons are no longer capable of maintaining connections with both cortical areas.
Effects of phenobarbital on saccharin and citric acid intake in fluid deprived rats

Rats were adapted to a 23 hr fluid deprivation schedule. Every third day animals were offered either 0.125 percent Na saccharin or 0.2 percent citric acid solutions in place of water during the 1 hr drinking session. Sodium phenobarbital was administered subcutaneously, 40 mg/kg, 15 min prior to drinking. Results indicate that the drug increases saccharin and citric acid consumption following the injections. No decreases in intakes of saccharin and citric acid occurred on subsequent postdrug days and the amounts of fluid consumed on these days were comparable to the baseline predrug days intakes.
Phosphatidylcholine-Specific Phospholipase C and Sphingomyelinase Activities in Bacteria of the Bacillus cereus Group

Bacillus anthracis is nonhemolytic, even though it is closely related to the highly hemolytic Bacillus cereus. Hemolysis by B. cereus results largely from the action of phosphatidylcholine-specific phospholipase C (PC-PLC) and sphingomyelinase (SPH), encoded by the plc and sph genes, respectively. In B. cereus, these genes are organized in an operon regulated by the global regulator PlcR. B. anthracis contains a highly similar cereolysin operon, but it is transcriptionally silent because the B. anthracis PlcR is truncated at the C terminus. Here we report the cloning, expression, purification, and enzymatic characterization of PC-PLC and SPH from B. cereus and B. anthracis. We also investigated the effects of expressing PlcR on the expression of plc and sph. In B. cereus, PlcR was found to be a positive regulator of plc but a negative regulator of sph. Replacement of the B. cereus plcR gene by its truncated orthologue from B. anthracis eliminated the activities of both PC-PLC and SPH, whereas introduction into B. anthracis of the B. cereus plcR gene with its own promoter did not activate cereolysin expression. Hemolytic activity was detected in B. anthracis strains containing the B. cereus plcR gene on a multicopy plasmid under control of the strong B. anthracis protective antigen gene promoter or in a strain carrying a multicopy plasmid containing the entire B. cereus plc-sph operon. Slight hemolysis and PC-PLC activation were found when PlcR-producing B. anthracis strains were grown under anaerobic-plus-CO2 or especially under aerobic-plus-CO2 conditions. Unmodified parental B. anthracis strains did not demonstrate obvious hemolysis under the same conditions.
The Soviet, Chinese and Albanian constitutions: Ideological divergence and institutionalized confrontation?

Western constitutional lawyers have often questioned the credib?ity of the constitutions of Communist-ruled states. Prior to 1975, the existing constitu tions of thirteen such states1 were modeled after the 1936 Stalin constitution of the USSR with essential variations. Such a constitutional fa?ade, often giving rise to a sense of political unreality, was not penetrated unt? the People's Republic of China (PRC) adopted its new constitution on January 17, 1975.2 This document injects into the Communist system a fuU measure of revolutionary dynamism. Similarly, the December 28, 1976, Constitution of the People's Socialist Republic of Albania3 embodies still more guidelines for continuing the revolution. However, the revolutionary dynamism of both documents and of the March 5,1978 PRC Constitution is completely missing from the Soviet Constitution, adopted on October 7, 1977,4 thereby divorc ing the Soviet Party-state from revolutionary Communism. According to Communist ideology, the creation of Communist Party-states, together with their prescribed political, economic, social and cultural pro grams, serves the Communist-led proletarian world revolution until its final victory. Since 1975, two distinct types of Communist Party-state constitu tions have emerged: revolutionary and revisionist. If a Communist Party-state reneges on its fundamental duty to serve the proletarian world revolution, it ceases to be revolutionary and deteriorates to revisionism. New constitutions were promulgated by Vietnam and Mongolia in 1960, East Germany in 1969 (amended in 1974), Bulgaria in 1971, and Hungary in 1972, and 'socialist' constitutions were proclaimed by Romania on August 20, 1965, by Yugoslavia on February 24,1974, and by Cuba on February 24, 1976. However, Uke the Soviet Constitution, these documents cannot be compared with the 1975 and 1978 PRC Constitutions or the 1976 Albanian Constitution in their revolutionary vigor. The 1975 and 1978 PRC Constitu tions are also fuUy compatible with the August 18,1977, Constitution of the Communist Party of China (CPC), which replaced its 1973 predecessor in pur suing the "continued revolution under the dictatorship of the proletariat."5 In effect, the two Chinese and 1976 Albanian Constitutions represent the
Characteristics of physiologic tremor in young and elderly adults

Abstract Objective : To determine the prevalence of tremor-related motor-unit entrainment in young and elderly adults. Methods : Postural hand tremor in neurologically healthy people, age ranges 20–42 (59 women and 41 men) and 70–92 (50 women and 50 men) years, was studied with accelerometry and forearm electromyogram (EMG). Tremor was recorded with and without a 300g load distributed over the distal half of the horizontally extended hand and was analyzed with Fourier spectral techniques. Results : No tremor-related spectral peak was found in the EMG of 59 young and 65 elderly controls, and inconsistent EMG peaks were observed in 29 young and 21 elderly. Twelve young and 14 elderly people exhibited a well-defined tremor-coherent EMG peak with and without 300g loading, and the frequency of the EMG peak decreased less than 1Hz in 8 young and 7 elderly. The EMG peak frequency was 9–12Hz during mass loading in all 8 young adults but in only two elderly adults. The other 5 elderly people had peak frequencies at 5–7Hz. Age had no significant effect on the frequency and amplitude of the mechanical-resonant component of hand tremor. Conclusions : Approximately 8% of young and elderly adult controls have an EMG-acceleration pattern that is indistinguishable from mild essential tremor. Significance : These results provide a framework for the interpretation of electrophysiologic studies in patients with suspected essential tremor.
Developmental Systems Theory and Youth Assets: A Primer for the Social Work Researcher and Practitioner

Despite ecological systems theory central role for social work practice as well as being a foundational feature of Developmental Systems Theory (DST), DST has gone under utilized by the social work profession. Youth assets as an operational component provides to the social work practitioner an opportunity to engage in development and implementation of concepts related to DST in order to enhance the development of youths using a community based approach. Social workers must become familiar with historical and theoretical understanding of key concepts in this primary prevention approach to addressing the needs of youths, and current methods used in measuring assets.
The Myth of Pervasive Mental Illness Among the Homeless

This paper calls into question the double-edged thesis that the majority of the homeless are mentally ill and that the streets of urban America have consequently become the asylums of today. We present data from a triangulated field study of nearly 1,000 unattached homeless adults in Texas that contradict this stereotypic imagery. We also suggest that this root image is due to the medicalization of the problem of homelessness, a misplaced emphasis on the causal role of deinstitutionalization, the heightened visibility of homeless individuals who are mentally ill, and several conceptual and methodological shortcomings of previous attempts to assess the mental status of the homeless. We conclude by arguing that the most common face on the street is not that of the psychiatrically-impaired individual, but of one caught in a cycle of low-paying, dead-end jobs that fail to provide the means to get off and stay off the streets.
The Energy Landscape for Ubihydroquinone Oxidation at the Qo Site of the bc 1 Complex inRhodobacter sphaeroides

Activation energies for partial reactions involved in oxidation of quinol by the bc 1complex were independent of pH in the range 5.5–8.9. Formation of enzyme-substrate complex required two substrates, ubihydroquinone binding from the lipid phase and the extrinsic domain of the iron-sulfur protein. The activation energy for ubihydroquinone oxidation was independent of the concentration of either substrate, showing that the activated step was in a reaction after formation of the enzyme-substrate complex. At all pH values, the partial reaction with the limiting rate and the highest activation energy was oxidation of bound ubihydroquinone. The pH dependence of the rate of ubihydroquinone oxidation reflected the pK on the oxidized iron-sulfur protein and requirement for the deprotonated form in formation of the enzyme-substrate complex. We discuss different mechanisms to explain the properties of the bifurcated reaction, and we preclude models in which the high activation barrier is in the second electron transfer or is caused by deprotonation of QH2. Separation to products after the first electron transfer and movement of semiquinone formed in the Qo site would allow rapid electron transfer to heme b L. This would also insulate the semiquinone from oxidation by the iron-sulfur protein, explaining the efficiency of bifurcation.
A technique for studying the nasal absorption of allergens in human beings.

Abstract 1.1. A technique which employs the anterior portion of the nasal septum as the site of application of antigen is presented for the study of absorption of allergens through the nasal mucous membrane. 2.2. The ready accessibility and visibility of the septum, and its flat surface which permits the use of constant amounts of antigen on constant absorptive areas, are among the outstanding advantages of the technique. 3.3. With the recommended technique, the absorption rate from the septum seems to be fairly representative of that from the anterior part of the respiratory nasal mucous membrane. 4.4. With the recommended technique, absorption of peanut antigen from the septum was demonstrated in 33 out of 34 subjects tested.
Activation of a Ca(2+)-dependent protein kinase involves intramolecular binding of a calmodulin-like regulatory domain.

Ca(2+)-dependent protein kinases (CDPKs) are regulated by a C-terminal calmodulin-like domain (CaM-LD). The CaM-LD is connected to the kinase by a short junction sequence which contains a pseudosubstrate autoinhibitor. To understand how the CaM-LD regulates a CDPK, a recombinant CDPK (isoform CPK-1 from Arabidopsis, accession no. L14771) was made as a fusion protein in Escherichia coli. We show here that a truncated CDPK lacking a CaM-LD (e.g. mutant delta NC-26H) can be activated by exogenous calmodulin or an isolated CaM-LD (Kact approximately 2 microM). We propose that Ca2+ activation of a CDPK normally occurs through intramolecular binding of the CaM-LD to the junction. When the junction and CaM-LD are made as two separate polypeptides, the CaM-LD can bind the junction in a Ca(2+)-dependent fashion with a dissociation constant (KD) of 6 x 10(-6) M, as determined by kinetic binding analyses. When the junction and CaM-LD are tethered in a single polypeptide (e.g. in protein JC-1), their ability to engage in bimolecular binding is suppressed (e.g. the tethered CaM-LD cannot bind a separate junction). A mutation which disrupts the putative CaM-LD binding sequence (e.g. substitution LRV-1444 to DLPG) appears to block intramolecular binding, as indicated by the restored ability of a tethered CaM-LD to engage in bimolecular binding. This mutation, in the context of a full-length enzyme (mutant KJM46H), appears to block Ca2+ activation. Thus, a disruption of intramolecular binding correlates with a disruption of the Ca2+ activation mechanism. CDPKs provide the first example of a member of the calmodulin superfamily where a target binding sequence is located within the same polypeptide.
Direct seeding of black locust reduces herbaceous competition

Abstract Concurrent direct seeding of herbaceous and woody species successfully established both groups of species. Black locust seedling survival and growth decreased with increasing herbaceous competition.
Understanding and Improving Teachers' Classroom Assessment Decision Making: Implications for Theory and Practice

Teacher assessment decision making is described as a process that may be important in developing a measurement theory for classroom assessment. Teacher beliefs and values about what and how to assess often conflict with the pressures of external demands, especially recent high-stakes large-scale testing. With this sense of tension, teachers make assessment decisions that will engage and motivate students and enhance learning. Implications for a measurement theory of classroom assessment, as well as teacher preservice and inservice, are explored. The article suggests that measurement specialists need to adapt technical testing principles to be more relevant to the nature of classroom assessment decision making.
MO-E-12A-01: Quantitative Imaging: Techniques, Applications, and Challenges

The first symposium in the Quantitative Imaging Track focused on the introduction of quantitative imaging (QI) by illustrating the potential of QI in diagnostic and therapeutic applications in research and patient care, highlighting key challenges in implementation of such QI applications, and reviewing QI efforts of selected national and international agencies and organizations, including the FDA, NCI, NIST, and RSNA. This second QI symposium will focus more specifically on the techniques, applications, and challenges of QI. The first talk of the session will focus on modalityagnostic challenges of QI, beginning with challenges of the development and implementation of QI applications in single-center, single-vendor settings and progressing to the challenges encountered in the most general setting of multi-center, multi-vendor settings. The subsequent three talks will focus on specific QI challenges and opportunities in the modalityspecific settings of CT, PET/CT, and MR. Each talk will provide information on modality-specific QI techniques, applications, and challenges, including current efforts focused on solutions to such challenges. Learning Objectives: 1. Understand key general challenges of QI application development and implementation, regardless of modality. 2. Understand selected QI techniques and applications in CT, PET/CT, and MR. 3. Understand challenges, and potential solutions for such challenges, for the applications presented for each modality.
Correlation between left frontal phospholipids and Wisconsin card sort test performance in schizophrenia

The relationship between frontal lobe phospholipid measures as measured by in vivo 31phosphorus magnetic resonance spectroscopic imaging and performance on the Wisconsin Card Sort Test was examined in 16 chronic schizophrenic patients and 13 normal controls. Lower left frontal phosphomonoester levels in the schizophrenics were associated with fewer categories achieved, lower percent conceptual level, and greater total errors. No significant correlations between frontal phospholipid measures and performance on the WCST were noted in the controls. The results suggest a relationship between altered left frontal phospholipid metabolism and a specific measure of frontal lobe neuropsychological functioning.
A zygomycotic infection in captive snakes

We report disseminated, fatal fungal disease involving subcutaneous and visceral tissues in 4 captive snakes (1 Elaphe guttata, 2 Crotalus horridus, and 1 Pituophis melanoleucus). The etiologic agent, which was abundant in the lesion, had a rounded form in vivo with a prominent nucleus. These cells averaged 17 µm in diameter and reproduced by fission, forming clusters of two or four daughter cells. The etiologic agent was isolated on Sabouraud dextrose agar from one of the snakes. It also grew well on various mycologic media, forming soft, raised, glabrous, tannish colonies. The colonies were composed of large spherical cells with prominent nuclei that reproduced by fission like those seen in tissue. In addition, some of the cells were observed to germinate, forming rudimentary hyphal filments that were up to 8 µm in diameter and 100 µm in length, with occasional septa and thick-walled structures regarded as azygospores. We consider the fungus to be a zygomycete that may belong to the order Entomophthorales.
Acquired Immune Deficiency Syndrome (AIDS): Speculations About Its Etiology and Comparative Immunology

Acquired immune deficiency syndrome (AIDS) in many aspects resembles formerly recognized immune deficiencies, but in its complexity and presumed viral etiology, it is a unique entity. Examples of overlapping features of AIDS and immune defects, infectious complications, and neoplasms are discussed. It is not known what are the exact underlying mechanisms that permit or prohibit infectious and neoplastic complications among the immunodeficiency syndromes compared, but both overlapping and differing features of these entities are significant enough to hold a clue for future understanding. AIDS resembles feline leukemia as this latter syndrome was described 10 years ago. The retrovirus causing feline leukemia is highly immunosuppressive; preleukemic and viremic cats often succumb to opportunistic infections. If patients with early AIDS harbor retroviruses related to the human T cell leukemia virus in their organs (lymph nodes, bone marrow), serotherapy with monoclonal antibodies directed to this virus may stop and reverse the severe immunosuppression, thus preventing the development of opportunistic infections.
Mutations and cell selections: Increased protein from regenerated rice tissue cultures

Abstract Rice calli derived from PI 353705, similar to Assam 5, were isolated from anthers cultured in vitro . Isolated aggregates of cells were plated on a medium containing 10 −3 M S -amioethylcysteine ( S -AEC) which inhibits cell growth. Cells resistent to the inhibitor were recovered and after an auxinnutritional stepdown were regenerated into whole plants. Seeds from the plant and subsequent progeny were analyzed for protein and lysine content. Callus tissues derived from advanced progeny were again cultured in the presence of the inhibitor to determine the heritability of S -AEC resistance. Seed from the S -AEC resistant mutant had a small increase in seed lysine, and pronounced increase in protein. The S -AEC resistance of callus tissue was transmitted through plant regeneration and meiosis and expressed in callus re-established from embryos of second generation seed. The high protein level was also expressed in advanced generations.
Predictors of Science Fair Participation Using the Theory of Planned Behavior

The purpose of this study was to use The Theory of Planned Behavior (TPB) to examine factors that predict junior high and secondary students' attitude toward participating in a district science fair competition (attitude toward behavior), beliefs about who would approve or disapprove of participation in a science fair (subjective norm), and perceptions of control about participating in the science fair (perceived behavioral control). Factors used to predict these included gender, type of school (public or private), grade level, GPA, participation in a gifted class, participation in a research course, requirement to complete a science fair project, and level of anxiety about completing a science fair project. Three hundred three participants completed a standard TPB questionnaire and the State-Trait Anxiety Indicator. Multiple regression models revealed that subjective norm and participation in a gifted class were predictors of attitude toward the behavior. Attitude toward the behavior, the science fair project counting toward a grade in science class, the parent's level of education, and the science fair entry being required predicted subjective norm. A discriminant function analysis found that type of school (public or private), parents' level of education, participation in a research program at school, grade level, and trait anxiety were the strongest predictors of perceived behavioral control. It was concluded that science fair entry appears to be involuntary, in conflict with NSTA's Position Statement on Science Fairs. Typically junior high students (whose parents have a higher level of education) attending private schools are required to enter science fairs, and the entry counts toward a grade in science class.