Ultrafast all-optical deflection based on an induced area modulation in nonlinear materials

A novel all-optical area-modulation scheme is suggested and experimentally demonstrated. In a mutually perpendicular interaction geometry inside a nonlinear material, the signal beam, which passes through an induced temporal prism formed by an area-modulated optical pump beam, undergoes a spatial phase modulation that leads to a beam deflection. Advantages and potential applications of the new all-optical modulation are addressed.

[Ultrastructure changes in tongue coating in chronic atrophic gastritis with deficiency cold or stagnated heat syndromes]

This paper reports the electron-microscopic observations of tongue exfoliated cells in 17 cases of chronic atrophic gastritis (CAG), 14 cases of chronic superficial gastritis, 9 cases of gastric carcinoma with deficiency cold (DC) and stagnated heat (SH) syndromes, and 12 normal cases. The results by electron-microscope showed that cell-organs and desmosome remains in the DC group were significantly higher than those in the SH group (P less than 0.05). However, the damage degree on the tonifibrils and surface structure of cells in the SH group was more serious than those in the DC group (P less than 0.05). The observations by light and electron-microscope revealed that the changes of microstructure and ultrastructure of tongue exfoliated cells in CAG did not distinguish from gastric carcinoma. But the changes in CAG was significantly different when compared with chronic superficial gastritis (P less than 0.05). From the above, the authors consider that the changes of tongue exfoliated cells could provide some morphological basis for the early stage of diagnosis.

Trophoblast-derived interleukin-1 (IL-1) stimulates the release of human chorionic gonadotropin by activating IL-6 and IL-6-receptor system in first trimester human trophoblasts

Interleukin-1 (IL-1) has a unique activity to stimulate the release of multiple hormones in a number of human and murine endocrine systems. IL-6 also expresses such activities by activating IL-6-receptor (R)-mediated signal transduction pathways. Since the placenta produces both of these cytokines and endocrine hormones such as hCG, we investigated how these cytokines regulate hCG release by normal trophoblasts. Trophoblasts purified by Percoll density gradient released hCG from 120 min after stimulation with recombinant (r) IL-1 alpha, and its release was dependent on the rIL-1 alpha concentration used. The rIL-1 alpha-stimulated trophoblasts released a molecule with IL-6 activity antecedently, as determined by an IL-6-dependent cell line, MH60.BSF2 cells. The IL-6 identity of the released molecule was confirmed by goat anti-IL-6 antiserum. rIL-1-mediated hCG release from trophoblasts was completely abrogated to the basal level by pretreatment of the trophoblasts with PM1, an anti-IL-6-R monoclonal antibody. Identical results were observed with rIL-1 beta. These results showed that rIL-1-induced hCG release was totally dependent on IL-6- and IL-6-R-mediated signal transduction in human trophoblasts. The presence of peripheral monocytes in the purified trophoblast fraction, however, induced a rapid decrease in IL-6 and hCG release after their maximal release, suggesting some regulatory interaction between trophoblasts and the monocytes. In contrast, rIL-1-mediated enhancement of IL-6 and hCG secretion by purified trophoblasts was no longer observed at 24 h compared with that of the unstimulated trophoblasts, while spontaneous hCG secretion was significantly inhibited by pretreatment of trophoblasts with PM1. The results showed that IL-6 and hCG secretion might also be regulated by a number of agents besides IL-1, and that hCG secretion as well as its release is dependent on IL-6 and IL-6-R system in trophoblasts.

[Experimental studies on the decoction siwu tang]

Using many kinds of modern instruments, we have measured the content of ferulic acid, eight trace elements, seventeen amino acids and water-soluble substances in various single drug decoctions, group-drug decoctions, and mixtures of various single drug decoctions of radix Angelicae sinensis, radix Rehmanniae, radix Paeoniae alba and Rhizoma chuanxiong that make up the decoction siwu tang. Absorption peaks in ultraviolet spectra have also been measured.

[Effect of sodium valproate on bicuculline-induced epileptiform activity in rat hippocampal slices in vitro]

Experiments were conducted on the rat hippocampal slices in vitro with the superfusion of bicuculline (Bcl, 10 mumol/L) and stimulation of Schaffer collaterals by single pulse to produce epileptiform activity of the pyramidal cells in CA1 area. In these experiments the effect of constant microinjection of sodium valproate onto the surface of slice on the epileptiform activity was studied. The results showed that the valproate, in concentration of 20, 30, 50 and 100 mmol/L, inhibited the Bcl-induced epileptiform activity in a manner of dose-dependence. It was deduced that the inhibition of epileptiform activity by the valproate is possibly related to the recovery of and increase in the inhibition mediated by GABAergic neurons and may be also to the non-synaptic mechanism of the valproate in rat hippocampus.

[Epidemiological interventional study on controlling endemic arsenism]

Residents exposed to high arsenical water in Kuitum area of Xinjiang Autonomous Region were studied by on the spot interventional trial experiment. After ridding arsenic from drinking water, 82.43% of chronic arsenism were either cured or showed improvements of health conditions and no new' cases of arsenism developed during the experiment. The values of arsenic in patiens hair and urine decreased by drinking water free of arsenic, but remained higher than those of normal residents. Our results showed that drinking normal water could help to progressively eliminate arsenic storage from the chronic arsenism. By means of electromyograph (EMG), we found that the nerve conduction velocities of patients increased significantly (P less than 0.01) and that -SH reactivities of peripheral blood corpuscles of patients recovered to the normal level.

Optical interconnect for a ring array of single-instruction-multiple-data processors

A novel optical interconnect scheme for a ring of single-instruction-multiple-data processing elements is proposed. This unexplored optical interconnect topology promises several important advantages over the conventional rectangular array topology, such as the use of space-invariant elements and identical interconnect latency for implementation.

[Model of stimulus train-induced bursting in rat hippocampal slice and the effect of L-glutamate on it]

A train of pulses (60 Hz, pulse duration 100 microseconds, train duration 2s, 2-3 fold maximal intensity) were applied to the CA3 stratum radiatum fiber pathway in rat hippocampal slices in vitro. Recordings of the field potentials were made from the stratum of CA3 pyramidal cells in response to these pulses so that the model of stimulus train-induced bursting (STIB) could be studied. It was a new and valuable model of epileptiform activity in hippocampal slices in vitro and the effect of L-glutamate (Glu) on STIB was also studied. Results showed that: 1. The number of train stimulus for a stable STIB averaged 5.5 +/- 2.1; the induced number of population spikes (PS) increased with an average in 5.2; and the STIB activity was long-last, persisting for up to 3-4 hours following the last train. 2. Superfusions of Glu in concentrations of 1, 2, and 3 mmol/L in hippocampal slices produced inhibition of STIB in CA3, but the first antidromic PS was unaffected, suggesting the site of inhibition is postsynaptic. The mechanisms related to the genesis of STIB and its inhibition by superfusion of Glu were discussed.

Fast digital optical multiplication using an array of binary symmetric logic counters

Because of the lack of fast, accurate, and large dynamic range analog-to-digital converters (ADCs), optical implementation of the digital multiplication through analog convolution (DMAC) algorithm yields a slow digital multiplier. By replacing both the optical adder and ADC arrays by an optical combinatorial logic counter array, a new optical fast digital multiplication method is proposed. Compared to the existing optical DMAC scheme, the new method promises both higher processing speed and accuracy. A comparison of this and some of the other optical and electronic fast digital multiplication schemes is also presented.

Intraspecific variation and sexual dimorphism in cranial and dental variables among higher primates and their bearing on the hominid fossil record

The extent and nature of dental and cranial sexual dimorphisms in extant hominoids have been investigated using reliably sexed samples of Homo sapiens (n = 75), Pan troglodytes (n = 51), Gorilla gorilla (n = 64) and Pongo pygmaeus (n = 43). Seventy nine measurements (35 dental, 16 mandibular and 28 cranial) formed the basis of the study. The patterns of mean differences and dispersions between the taxa were compared across the anatomical regions and the group structures of the separate sex samples were analysed using multivariate (PCA and CVA) analysis. Within and between group variations were compared across the taxa to investigate whether any variables were consistently effective sex or taxonomic discriminators. The study confirmed that there were differences in degree and pattern of sexual dimorphism between the extant higher primates, but the results did not substantiate the distribution of patterns as suggested by Oxnard et al. (1985); in particular there was no evidence of the dispersion differences noted by those authors. There were sufficient consistencies in the behaviour of variables across the four taxa to suggest that all canine dimensions, postcanine crown buccolingual dimensions and mandibular and cranial breadths are generally good sex discriminators, whereas some incisor dimensions, postcanine crown mesiodistal dimensions and facial heights are more effective at discriminating between the four extant taxa included in this study.

Fast optical binary multiplication using a sign/logarithm number system

A new fast binary multiplication scheme based on a nonholographic optical content-addressable memory (CAM) is presented. By using a sign/logarithm number (SLN) system, the multiplication operation is performed through a binary logarithmic addition. A three-stage CAM-based multiplication scheme is proposed in which the first CAM converts input binary numbers to SLN's, the second CAM performs a fixed-point binary addition, and the third CAM converts this SLN result back to the binary number system. The design and experimental demonstration of a 7-bit nonholographic optoelectronic CAM-based multiplier are presented.

Real time self-pumped optical phase-conjugator based igner distribution processor for complex signals

Based on a combination of linear shift-invariant optical elements and a nonlinear photorefractive crystal serving as a self-pumped optical phase-conjugator, the real time optical generation of an auto- and cross- Wigner distribution for complex signals is demonstrated.

Purification, characterization and mechanism of action of scatter factor from human placenta

Scatter factor (SF) causes contiguous sheets of epithelium to spread and cells to separate from each other. SF also increases the velocity, area, and reduces the circularity of individual cells. These changes are mediated in part by alterations in protein synthesis, protein phosphorylation, cytoskeletal reorganization, and cell surface components. SF has been purified from the conditioned medium of ras transformed 3T3 cells and human placenta. Sequence information suggests that SF from 3T3 cells is closely related to hepatocyte growth factor. SF is a glycoprotein, but glycosylation is not necessary for its activity. Glycosylation of target cell proteins, however, is required for SF action.

Pharmacological and biochemical properties of saxiphilin, a soluble saxitoxin-binding protein from the bullfrog (Rana catesbeiana)

Supernatant fractions of various tissues and plasma from the North American bullfrog, Rana catesbeiana, specifically bind saxitoxin with high affinity. Binding of [3H]saxitoxin to bullfrog plasma follows single-site behavior with an equilibrium dissociation constant of Kd = 0.16 +/- 0.03 nM at 0 degrees C and a maximum binding capacity of 380 +/- 60 pmole/ml plasma. High-affinity binding of [3H]saxitoxin is chemically specific since it is unaffected by tetrodotoxin and a variety of cationic peptides, amino acids and drugs. The structure-activity dependence of binding to this site was investigated with eight different natural and synthetic derivatives of saxitoxin. Substitution of the carbamoyl side chain or the C-12 beta-hydroxyl group of saxitoxin with a hydrogen atom had little effect on binding affinity, but addition of a hydroxyl group at the N-1 position decreased the binding affinity from 430- to 710-fold in three different molecular pairs. High performance size exclusion chromatography of supernatant from bullfrog skeletal muscle showed that the [3H]saxitoxin-binding component migrates with an apparent molecular weight of Mr = 74,000 +/- 8000 or a Stokes radius of 35 +/- 2A. The [3H]saxitoxin-binding protein in skeletal muscle extract or plasma is retained on a cation-exchange column at pH 6.0, suggesting that the protein contains a region of exposed basic residues. Column isoelectric focusing of a sample from plasma indicated that the protein has a basic isoelectric point near pH = 10.7.(ABSTRACT TRUNCATED AT 250 WORDS)

Receptor-mediated deactivation of Gk in cardiac myocytes

The muscarinic potassium current IK(ACh) of atrial myocytes can be evoked in the absence of agonists by intracellular application of stable GTP analogs (GXP). This receptor-independent opening of K(ACh) channels is a consequence of the direct activation of the guanyl nucleotide binding protein Gk that couples muscarinic receptors to K(ACh) channels, and was previously thought to be unaffected by subsequent application of agonist. We report here that in the presence of GTP, application of a pulse of muscarinic agonist to atrial cells can abolish the GXP-induced IK(ACh). The results imply that in intact cells the agonist-bound receptor can interact with Gk not only in its inactive, GDP-bound form, but also in its active, GXP-bound form in a process that promotes the release of guanine nucleotide from its binding site.

Tumor necrosis factor-alpha synergizes with IFN-gamma in mediating killing of Leishmania major through the induction of nitric oxide

CBA mice develop cutaneous lesions when infected with Leishmania major. The disease development was significantly reduced by injecting into the lesion a combination of rIFN-gamma and rTNF-alpha. The doses of IFN-gamma and TNF-alpha used were suboptimal in that either cytokine alone did not have any effect. The therapeutic effect of IFN-gamma and TNF-alpha in vivo is reflected in their ability to activate macrophages to kill the intracellular parasites in vitro. The macrophage leishmanicidal activity induced by TNF-alpha and IFN-gamma can be completely inhibited by a specific inhibitor (L-NG monomethyl arginine) of nitric oxide synthesis. There was a direct correlation between the intracellular killing of the parasites and the production of nitric oxide by the macrophages. In contrast, there was no correlation between leishmanicidal activity and superoxide production by macrophages.

Tumor necrosis factor-alpha synergizes with IFN-gamma in mediating killing of Leishmania major through the induction of nitric oxide

CBA mice develop cutaneous lesions when infected with Leishmania major. The disease development was significantly reduced by injecting into the lesion a combination of rIFN-gamma and rTNF-alpha. The doses of IFN-gamma and TNF-alpha used were suboptimal in that either cytokine alone did not have any effect. The therapeutic effect of IFN-gamma and TNF-alpha in vivo is reflected in their ability to activate macrophages to kill the intracellular parasites in vitro. The macrophage leishmanicidal activity induced by TNF-alpha and IFN-gamma can be completely inhibited by a specific inhibitor (L-NG monomethyl arginine) of nitric oxide synthesis. There was a direct correlation between the intracellular killing of the parasites and the production of nitric oxide by the macrophages. In contrast, there was no correlation between leishmanicidal activity and superoxide production by macrophages.

Interaction of a macrocyclic bisacridine with DNA

The binding of the macrocycle SDM to DNA was investigated by visible spectroscopy, stopped-flow kinetics, and NMR spectroscopy. SDM is composed of two 9-aminoacridines linked via the amino groups by a spermine side chain and via the 4-positions by a N,N'-[(methylthio)ethyl]succinamide side chain [Zimmerman, S. C., Lamberson, C. R., Cory, M., & Fairley, T. A. (1989) J. Am. Chem. Soc. 111, 6805-6809]. The visible spectrum of SDM bound to poly[d(A-T)]2 or poly[d(G-C)]2 is red-shifted relative to the spectrum of SDM alone and displays considerable hypochromicity. Results from titrations of SDM with polymer indicate a binding site size of three base pairs per macrocycle. The dissociation constant for SDM bound to either poly[d(A-T)]2 or poly[d(G-C)]2 is an order of magnitude lower than that for a similar bisacridine linked only by a spermine side chain. In addition, the dependence of the dissociation constant on ionic strength is significantly reduced. NMR studies of SDM complexes with poly[d(A-T)]2 or a tetramer, d(CGCG)2, show that intercalation is the mode of binding. The magnitudes of the chemical shift differences for SDM aromatic protons in the free and bound states support intercalation with the acridine ring systems essentially parallel to the long axis of the base pairs. Cross peaks from NOESY spectra of the SDM complex with d(CGCG)2 further support this mode of binding and provide information on the structure of the complex. The results are analyzed for consistency with each of three binding models: (i) bisintercalation with the two side chains in the same groove; (ii) bisintercalation according to the neighbor-exclusion principle with the two side chains in opposite grooves; and (iii) bisintercalation with two side chains in opposite grooves but with violation of the neighbor-exclusion principle. Model i is found to be unlikely on the basis of all evidence obtained, including preliminary modeling studies. Both models ii and iii can be reconciled with the experimental evidence and from a modeling standpoint are energetically feasible.