bluuebunny/crossref_metadata_2025 huggingface dataset:
In vivo effects of recombinant granulocyte‐colony stimulating factor in athymic nude mice
Authors: Pojda Zygmunt , Aoki Yoshiro , Tsuboi Atsushi
Published: July 2007

The possible role of T lymphocytes in in vivo regulation of haemopoiesis by recombinant human granulocyte‐colony stimulating factor (rhG‐CSF) was evaluated, Athymic nude (nu/nu) mice and their normal (+/+) littermates were injected subcutaneously twice daily with 100 μg/kg per day of rhG‐CSF for 5 days. Such parameters as number of neutrophils in blood, spleen weight and cellularity, bone marrow cellularity, and number of stem and progenitor cells (colony forming units in spleen [CFU‐S], mix colony forming cells [Mix‐CFC], granulocyte‐macrophage colony forming cells [GM‐CFC]) in bone marrow and spleen were evaluated. Some effects of the rhG‐CSF treatment were similar in nu/nu and +/+ mice. Others, however, were to some extent different in the two groups of animals. It is concluded that T lymphocytes may be partially responsible for some of the effects of rhG‐CSF in vivo activity.
The interleukin‐2 receptor on cord blood and nulliparous mononuclear cells is downregulated by maternal and cord blood serum
Authors: Vanderbeeken Yves Edouard , Duchateau Jean , Van Boogaert L. , Desseilles P. , Collet Henry , Lucas Adam
Published: July 2007

The concentration of interleukin‐2 receptor(IL‐2R)on maternal, cord blood and unrelated nulliparous mononuclear cells has been studied after a previous phytohaemagglutinin (PHA) stimulation. Furthermore, the inhibitive action of maternal and cord blood serum on the IL‐2R expression of stimulated nulliparous and cord blood lymphocytes has been shown. A downregulation of the [3H]‐thymidine uptake by these PHA treated cells previously incubated in maternal and cord blood serum has been observed. Retroplacental serum was the most inhibitive experimental medium. The IL‐2R modulation property of maternal serum has been studied during the pregnancy. Appearing quite early (in the sixth week), the maternal serum dependent inhibitive factor vanished, 2 to 3 weeks after delivery. After a study of the different serum components, it is suggested that the IL‐2R downregulating molecule is included in the maternal immunoglobulin (IgG) fraction. Further experiments suggest that the addition of recombinant IL‐2 during the action of low doses of maternal IgG allows a partial re‐expression of the IL‐2R. However, at physiological concentrations of IgG, the IL‐2R downregulation becomes irreversible.
Production and characterization of a new monoclonal antibody to colorectal carcinoma
Authors: Teh Jin‐Ghee , Thompson Christopher H. , McKenzie Ian F. C.
Published: July 2007

This study describes a new murine monoclonal antibody (MoAb) 5C1 raised against human colorectal carcinoma, which gave a differential reaction on formalin‐fixed sections of the gastrointestinal tract. The MoAb 5C1 of immunoglobulin M (IgM) isotype reacted with both the cytoplasm and membrane of all normal colonic epithelia, and with all benign colonic polyps and all premalignant colonic lesions. However, there was a decreased expression of the 5C1 antigen in most cases of colonic malignancy and it was this feature that makes MoAb 5C1 unique. The distribution of the 5C1 epitope in normal gastrointestinal tract is limited to a few epithelial cells in the mid‐portion of the small intestine but this distribution increased progressively down the digestive tract until it was found on > 90% of normal epithelial cells (in membrane and cytoplasm) of the colon. In addition, the 5C1 epitope was present on mucin secreting cells from normal organs of the gastrointestinal, reproductive and pulmonary tract and benign and malignant tissues of the colon. On Western blots, MoAb 5C1 was found to detect a heterogeneous population of molecules with molecular weights >100 kDa with the strongest staining bands found between 230 and 300 kDa. MoAb 5C1 does not detect carcino‐embryonic antigens (CEA), human milk fat globules (HMFG), human lymphocyte antigens (HLA) or ABO blood group antigens. The combination of its presence in mucin secreting cells and its broad molecular weight bands suggest that the antigen detected is a mucin.
Antigenic requirements for stimulation and target cell recognition by immune and non‐immune cytotoxic T lymphocytes
Authors: Owen J. A. , Grahl K. T. , Zador A. , Dorer D. R. , Klein L. , Rubin M. B.
Published: July 2007

The molecular requirements for recognition of antigen‐modified cells by cytotoxic T lymphocyte precursors (CTLp) and their activated progeny, cytotoxic T lymphocytes (CTL), have been compared using haptenated stimulator and target cells. The antigen density requirements of T cell recognition by fluorescein‐specific CTLp and CTL derived both from naive mice and from animals previously primed in vivo were determined. The cell surface hapten concentration required to stimulate CTLp cannot be distinguished from that required on target cells for lysis by their mature daughter CTL 5–7 days later. However, if the CTL (and their precursor CTLp) are derived from mice primed in vivo with hapten‐conjugated cells, they require lower cell surface hapten densities for recognition than do the analogous T cell populations from naive animals. Thus, the maturation of CTLp inio CTL during 5–7 days in vitro does not result in any functionally relevant change in the nature or density of antigen receptors on the surface of the T cell. This is in contrast to the apparent selection which occurs over longer time periods in vivo following priming.
Dual mechanisms of inhibition of the immune response by enterocytes isolated from the rat small intestine
Authors: Pang Gerald , Clancy Robert , Saunders Heather
Published: July 2007

Antigen presentation by enterocytes isolated from the rat small bowel was studied by using T cell proliferation, and immunoregulatory function in an antigen‐driven culture system, as indicator systems. Lymph node T cells obtained from rats immunized with ovalbumin (OA) failed to divide when cultured for 4 days in the presence of freshly isolated Ia+ enterocytes and OA. However, cell division was noted when enterocytes were removed after 18 h by Percoll gradient centrifugation, followed by culture of T cells for a further 4 days in the absence of antigen. The failure to divide in the primary culture was due to the secretion by enterocytes of a dialysable non‐specific inhibitor. Antigen presentation by enterocytes was specific and was inhibited by monoclonal mouse anti‐rat Ia antibody, OX6. An epithelial cell line (REC‐2) was established from normal rat small intestine. These cells expressed Ia molecules following incubation with Concanavalin‐A stimulated spleen cell supernatant, and were capable of both presenting antigen, and inducing interieukin‐2 (IL‐2) production, when cultured with primed T cells. Furthermore, Ia+ REC‐2 cells functioned as stimulators in a primary mixed lymphocyte reaction (MLR). Both OA‐primed T cells activated by enterocytes and antigen, and allogeneic MLR‐activated T cells, mediated suppression which was not specific for the initiating antigen. These experiments indicated two mechanisms mediate suppression of cell division in gut mucosa. The contribution of these mechanisms to the control of inflammation at mucosal sites requires investigation.
Improvement in sensitivity of enzyme‐linked immunosorbent assay for tumour necrosis factor
Authors: McLaughlin P. Jeremy , Elwood Ngaire J. , Ramadi Lanny T. , Pica Marie R. , McKenzie Ian F. C.
Published: July 2007

Various protocols were used in the development of enzyme‐linked immunosorbent assays (ELISA) to improve the sensitivity and range of detection of human tumour necrosis factor‐α (TNF‐α). ELISA can provide a specific, sensitive and rapid method for detection of TNF‐α in patient's sera, and it is important that the assay used should be sufficiently sensitive to detect low levels of TNF‐α. The double sandwich ELISA proved to be the most sensitive, detecting <0080 ng/mL TNF. Of eight different protocols, one assay using a purified monoclonal antibody to human TNF‐α and rabbit polyclonal anti‐TNF‐α antibody had the greatest sensitivity and range of detection. The study illustrates methods for the development of sensitive immunoassays which may have applications in many assay systems.
Pasteurella multocida infections in mice with reference to haemorrhagic septicaemia in cattle and buffalo
Authors: Ramdani H. J. S. Dawkins , Johnson R. B. , Spencer T. L. , Adler B.
Published: July 2007

Haemorrhagic septicaemia (HS) is an infectious disease of cattle and buffalo caused by particular serotypes of Pasteurella multocida and is one of the most economically important livestock diseases in South‐East Asia. While HS has been recognized for many years, very little is understood about the disease, primarily because of the expense of cattle and a lack of suitable animal models. The suitability of using mice to study HS was assessed using parameters such as the critical pathogenic dose, kinetics of infection, pathology of disease and resistance to reinfection. Pasteurella multocida M1404, the type strain for Carter group B, the serotype responsible for Asian HS, was injected intraperitoneally into BALB/c mice. As few as 20 colony forming units produced an overwhelming septicaemia in mice in less than 30 h. The kinetics of infection demonstrated a very rapid in vivo multiplication rate. There was no evidence of inhibition of bacterial cell growth by natural host defence mechanisms, even with the very small inocula used. The gross pathology of the disease in mice was characterized by splenomegaly, lymphadenopathy and petechial haemorrhages similar to that observed in cattle and buffalo with HS. Mice were found to develop a short‐lived resistance to reinfection following a primary infection which had been successfully treated with antibiotics. The mouse would seem to provide an ideal tool by which to study HS, but warrant further studies in order to be able to critically assess it as a model for this economically important disease.
Cytotoxic effects of gingival retraction cords on human gingival fibroblasts in vitro
Authors: Liu C.‐M. , Huang F.‐M. , Yang L.‐C. , Chou L. S.‐S. , Chou M.‐Y. , Chang Y.‐C.
Published: July 2007

summary  The objective of this study was to determine the cytocompatibility of three different extracts of gingival retraction cords and to compare the cytotoxic effect of these materials on human gingival fibroblasts. Gingival retraction cords impregnated with aluminium sulphate (Gingi‐Aid), dl‐adrenaline HCl (Gingi‐Pak) and non‐drug‐impregnated cord (Gingi‐Plain) were eluted with culture medium for 10 min and 24 h. Cytotoxicity was judged using a tetrazolium bromide reduction assay. Our data demonstrated that gingival retraction cords applied alone almost completely inhibited cell viability (P < 0·05). In addition, the results also showed that the eluates from aluminium sulphate‐impregnated cord, dl‐adrenaline HCl‐impregnated cord and non‐drug‐impregnated cord were cytotoxic to primary human gingival fibroblast cultures (P < 0·05). The cell viability of incubation of gingival fibroblasts containing 10‐min eluates of aluminium sulphate, dl‐adrenaline HCl and non‐drug‐impregnated cord was 61, 21 and 70%, respectively. The cell viability of incubation of gingival fibroblasts containing 24 h eluates of aluminium sulphate, dl‐adrenaline HCl and non‐drug‐impregnated cord was 68, 58 and 72%, respectively. It was found that dl‐adrenaline HCl‐impregnated gingival retraction cord was the most toxic gingival retraction cord among the materials tested in all cultures (P < 0·05). The cytotoxicity decreased in an order of dl‐adrenaline HCl‐impregnated cord > aluminium sulphate‐impregnated cord > non‐drug‐impregnated cord. The extent or degree of the cytotoxicity depended on the materials tested. Gingival retraction cords have significant potential for gingival toxicity. Careful management of gingiva retraction cords would lower the risk of potential gingival tissue damage during clinical application procedure and thus increase the success of prosthodontic procedures.
Evaluation of fracture resistance of endodontically treated maxillary premolars, restored with ceromer or heat‐pressed ceramic inlays and fixed with dual‐resin cements
Authors: Ortega V. L. , Pegoraro L. F. , Conti P. C. R. , do Valle A. L. , Bonfante G.
Published: July 2007

summary  The aim of this study was to evaluate the fracture resistance of endodontically maxillary premolars restored with mesio‐occlusal‐distal (MOD) inlays made with ceramic (IPS‐Empress 2) and ceromer (Targis) and luted with three different dual‐cured resin cements (Enforce, Variolink II, Panavia F). Sixty maxillary premolars were randomly distributed into six groups, according to their mesio‐distal and facio‐lingual dimensions. The teeth were endodontically treated and MOD cavities prepared. After the restorations were cemented, the samples were thermocycled and submitted to an axial compressive load by the action of a rounded end steel cylinder contacting the incline planes of occlusal surfaces of the teeth. The mode of fracture was analysed with a microscope. The best results were found with the combinations (cement/restorative material) Enforce/Targis (107·57 kgf) and Enforce/Empress (90·21 kgf) followed by Variolink II/Targis (86·44 kgf)–Variolink II/Empress (84·07 kgf) and Panavia F/Targis (82·43 kgf)–Panavia F/Empress (76·73 kgf). Analysis of variance (P < 0·05) showed a significant difference between Enforce and Panavia cements regardless of the restorative material. Considering the same luting agent there was no statistically significant difference between the restorative materials. Fracture of lingual cusps occurred in 55 of the 60 teeth and most of them were of the cohesive type.
The long‐term effectiveness of five current desensitizing products on cervical dentine sensitivity
Authors: Duran I. , Sengun A.
Published: July 2007

summary  The aim of this study was to compare the long‐term effectiveness of five desensitizing products on 25 male and 27 female patients (total 52) aged 21–67 years (mean 36 ± 7 years) suffering from cervical dentine sensitivity. All subjects were seen by the same examiner (ID) who was blinded to the applied treatment for 3‐month clinical study. Patients were asked to record their overall sensitivity by marking a point on a 10 cm Visual Analogue Scale (VAS). Two hundred and seventy‐seven sensitive teeth were treated by one of the five desensitizing products, all of which were placed following manufacturers’ instructions by the other investigator (AS). A paired (split mouth) study design was used and selection of quadrants was randomized. At the post‐treatment and at 10 days and 3 months periods, sensitivity measurements were recorded by the same investigator (ID). Statistical analysis showed that all of the VAS scores at post‐treatment evaluation points were significantly decreased compared with baseline data (P < 0·05). There was a significant reduction in mean sensitivity scores in the Protect Liner F and the Health‐Dent Desensitizer groups when compared with Fluoline varnish at the 10‐day time point (P < 0·05). At 3 months, the Protect Liner F group continued to show a significantly reduced sensitivity level when compared with Health‐Dent Desensitizer, Single Bond, Fluoline and Gluma Desensitizer (P < 0·05). The present study demonstrated that although at the end of 3‐month evaluation period all desensitizers showed lower VAS sensitivity values compared with baseline, there were differences in the level of reduction of cervical dentine sensitivity.
Changes in temporomandibular disorders after treatment with new complete dentures
Authors: Dervis E.
Published: July 2007

summary  A total of 250 edentulous patients (118 non‐denture and 132 denture wearing) awaiting treatment for new complete dentures were examined for signs and symptoms of temporomandibular disorders. Signs and symptoms of temporomandibular disorder (TMD) were evaluated before prosthetic treatment, 3 months and 3 years after denture insertion by means Helkimo's Anamnestic and Clinical Dysfunction Indices. Before treatment began, patients were observed to have a low prevalence of signs and symptoms of TMD. This prevalence decreased, but was not statistically significant, in the 3 months and 3 years after denture insertion. No statistically significant correlations were found between signs and symptoms of TMD and denture retention, stability, occlusal errors, freeway space, age of present denture, or number of sets of dentures.
Effect of sample thickness on bite force studied with a multiple‐point sheet sensor
Authors: Kohyama K. , Hatakeyama E. , Sasaki T. , Azuma T. , Karita K.
Published: July 2007

summary  The aim of this study was to investigate the relationship between thickness of sample food and bite force. We designed a new sensor that can detect the pressure distribution between the incisor and molar teeth on one side, and the contact area between the food samples and the teeth. The force and contact area were directly measured in real time using the multiple‐point sheet sensor, which is a very thin and flexible pressure‐sensing device. Silicone rubber blocks were used as a sample food and were chewed with incisors and molars by 10 healthy women. The peak force, contact area, duration and impulse were greater between the incisors for a thicker specimen. The active pressure, defined as the ratio of the force to contact area, at peak was similar for different thicknesses. In contrast, with a 2 mm thick sample, the peak force and force related parameters were greatest in molar chewing. The force, contact area and duration were greater for molar chewing cycles than incisor ones. We verified that the thickness of samples influenced the chewing force of humans and the effects differed between incisors and molars.
Occlusal adjustment for treating and preventing temporomandibular joint disorders
Authors: Koh H. , Robinson P. G.
Published: July 2007

summary  To assess the effectiveness of occlusal adjustment (OA) for treating temporomandibular disorders (TMD) in adults and preventing TMD. The Cochrane Controlled Trials Register, MEDLINE and EMBASE were comprehensively searched using the Cochrane methods. Reports and review articles were retrieved. Unpublished reports or abstracts were considered from the SIGLE database. All randomized or quasi‐randomized controlled trials comparing OA with placebo, reassurance or no treatment in adults with TMD. The outcomes were global measures of symptoms, pain, headache and limitation of movement. Data collection and analysis followed the Cochrane Oral Health Group's statistical guidelines. Results showed no difference between OA and control group in symptom‐based outcomes for treatment or incidence of symptoms for prevention. There is no evidence that OA treats or prevents TMD. OA cannot be recommended for the management or prevention of TMD. Future trials should use standardized diagnostic criteria and outcome measures when evaluating TMD.
Efficient blue and white organic light-emitting devices based on a single bipolar emitter
Authors: Tao Silu , Lee Chun Sing , Lee Shuit-Tong , Zhang Xiaohong
Published: July 2007

Excellent bipolar carrier transport properties of 2,7-dipyrenyl-9,9′-dimethyl-fluorene (DPF) have been elucidated by using different device structures. A nondoped device using DPF as host emitter showed highly-efficient blue emission with a maximum efficiency of 6.0cd∕A and CIE coordinates of x=0.15 and y=0.19. Another device based on rubrene-doped DPF as emission layer gave pure high-efficiency white emission with good color stability, a maximum efficiency of 10.5cd∕A, and CIE coordinates of x=0.28 and y=0.35. The excellent bipolar transport capability and high performance as both emitter and host suggest that DPF is an efficient and versatile material for various applications in organic light-emitting devices.
Ultrafast thermal processing and nanocalorimetry at heating and cooling rates up to 1MK∕s
Authors: Minakov Alexander A. , Schick Christoph
Published: July 2007

To generate artificial materials with advanced physical and chemical properties and to study phase transition kinetics on submillisecond time scale, an ultrafast nonadiabatic membrane nanocalorimeter was constructed. A set of commercially available membrane gauges for ultrafast nanocalorimetry has been developed. The gauges placed in a thermostat with controlled helium gas pressure and temperature can be utilized as devices for thermal processing and calorimetry with resolution of 1nJ∕K. Controlled ultrafast cooling, as well as heating, up to 106K∕s can be attained for nanogram samples. The maximum cooling rate is inversely proportional to the radius of the heated region of the gauge, which was in the range of 10–100μm depending on the gauge. The minimum addenda heat capacity was 3nJ∕K. The dynamic heat-transfer problem for the temperature distribution in the membrane-gas system at ultrafast processing has been solved. The characteristic rate R0 corresponding to quasistatic limit of the temperature change in the membrane-gas system has been found to be equal to 105K∕s for a 1μm thick silicon nitride membrane in helium gas. Calorimeter performance at ultrafast rates has been verified by a set of test experiments. The method was applied for thermal processing and calorimetric measurements in a set of linear polymers. It has been established that nearly amorphous polyethylene can be obtained at a cooling rate of 106K∕s.
Electrical and structural characterization of as-grown and annealed hydrothermal bulk ZnO
Authors: Kassier G. H. , Hayes M. , Auret F. D. , Mamor M. , Bouziane K.
Published: July 2007

Hall effect measurements in the range 20–370 K on as-grown and annealed hydrothermal bulk ZnO have been performed. The bulk conductivity in the highly resistive as-grown sample was found to decrease and then increase after annealing at 550 °C and 930 °C, respectively. The conduction in the as-grown material is attributed to a deep donor which is replaced by a much shallower donor after annealing at 930 °C. Annealing at both temperatures also produced strong surface conduction effects. Nondegenerate low-mobility surface conduction dominated the electrical properties of the sample annealed at 550 °C, while a degenerate surface channel was formed after annealing at 930 °C. In addition, Rutherford backscattering and channeling spectrometry (RBS/C) was used to assess the effect of annealing on the crystalline quality of the samples. RBS/C measurements reveal that annealing at 930 °C leads to significant improvement of the crystalline quality of the material, while annealing at 550 °C results in the segregation of a nonchanneling impurity at the surface.
Ordering promotion and intergrain decoupling in FePt thin films by Ta and Ta/Bi buffer layers
Authors: Zhang L. J. , Cai J. W. , Pan H. Y.
Published: July 2007

The magnetic properties and microstructure of annealed near-equiatomic FePt thin films with Ta and Ta/Bi buffer layers have been investigated. While Ta buffer layer effectively enhances the coercivity of FePt thin films, the insertion of a thin Bi layer between FePt and Ta layers further boosts the coercivity multifold. Most representatively, the 12 nm Fe48Pt52 films without buffer and with Ta (6 nm), and Ta (6 nm)/Bi (2 nm) buffer layers after annealing at 400 °C have coercivity of 0.95, 2.7, and 9.2 kOe, respectively, indicating greatly promoted L10 ordering of FePt films through a buffer layer of Ta, especially Ta/Bi. Moreover, the intergrain exchange interaction is appreciably reduced for the annealed Ta/FePt film and almost decoupled for the Ta/Bi/FePt film after annealing. The structural and chemical analyses reveal that Pt atoms transfer from FePt layer into the Ta layer while Ta atoms migrate into the grain boundaries of the FePt layer, and the thin Bi insertion layer reinforces the migration of Ta and Pt due to the outdiffusion of Bi during annealing, which results in the improvement of the ordering as well as the weakening of the intergrain exchange coupling for Ta/FePt, especially for Ta/Bi/FePt.
Time resolved measurements of melting and solidification in Si using third harmonic generation of light
Authors: Gundrum Bryan C. , Averback Robert S. , Cahill David G.
Published: July 2007

Time resolved measurements of melting and solidification on (001) Si using third harmonic generation (THG) were performed with subpicosecond time resolution. Following 120fs laser pulses at fluences above the melt threshold, the circularly polarized THG signal decreases by over three orders of magnitude. It regains its original intensity on solidification after ≈2ns. The authors show that the THG signal is sensitive to specimen temperature, decreasing by a factor of ≈5 between 298K and the melting temperature. The work demonstrates that complete thermal and phase histories can be obtained during ultrafast laser heating using single-shot THG experiments.
Spin-polarized scanning tunneling microscopy in field emission mode
Authors: Kubetzka A. , Bode M. , Wiesendanger R.
Published: July 2007

Image-potential states in front of the Fe(110) surface have been investigated by spin-polarized scanning tunneling spectroscopy. For the n=1 state energetic splittings of up to 25meV are observed in the spectroscopic data measured above oppositely magnetized surface areas. The technique offers the possibility to access the spin dependence of image-potential states on a local scale. These states can be used as a sensitive probe of surface magnetism, allowing high resolution magnetic imaging at tip-sample distances larger than in normal tunneling experiments, thereby reducing the probability of accidental tip-surface collisions.
Aggregation-induced emissions of tetraphenylethene derivatives and their utilities as chemical vapor sensors and in organic light-emitting diodes
Authors: Dong Yongqiang , Lam Jacky W. Y. , Qin Anjun , Liu Jianzhao , Li Zhen , Tang Ben Zhong , Sun Jiaxin , Kwok Hoi Sing
Published: July 2007

Nonemissive tetraphenylethene (TPE) 1 and its diphenylated derivative 2 were induced to emit intensely by aggregate formation. Crystalline aggregates of the dyes emitted bluer lights than their amorphous counterparts. The emissions of the TPE dyes could be switched off and on continuously and reversibly by wetting and dewetting with solvent vapors, respectively, manifesting their ability to optically sense volatile organic compounds. The light-emitting diodes fabricated from 1 and 2 were turned on at ∼2.9 and ∼5V and emitted blue lights with maximum luminance of ∼1800 and ∼11000cd∕m2, respectively.
Magnetoelectric relaxor
Authors: Levstik A. , Bobnar V. , Filipič C. , Holc J. , Kosec M. , Blinc R. , Trontelj Z. , Jagličić Z.
Published: July 2007

The site and charge disordered solid solution 0.8Pb(Fe1∕2Nb1∕2)O3–0.2Pb(Mg1∕2W1∕2)O3 is a magnetoelectric relaxor which shows broad and frequency dependent maxima both in the electric as well as in the magnetic susceptibilities. The Vogel-Fulcher-type electric relaxor freeze-out is accompanied by a significant magnetic anomaly demonstrating magnetoelectric coupling. Thus, a magnetoelectric effect is observed in a system exhibiting only mesoscopic and no long range order.
First-principles calculations of the effect of Pt on NiAl surface energy and the site preference of Pt
Authors: Yu R. , Hou P. Y.
Published: July 2007

Pt-modified NiAl is widely used as a coating material in industry. In this study, the surface energies of NiAl with and without Pt are investigated using first-principles calculations. The presence of Pt in NiAl takes the surface electronic states to higher energies, resulting in an increased surface energy, which explains some of the beneficial effects of Pt on the oxidation resistance of NiAl. The electronic structure of NiAl–Pt alloys is also analyzed in terms of the site preference of Pt in NiAl. Results show that Pt bonds strongly to Al, giving its site preference on the Ni site.
In situ scanning tunneling microscopy observations of polycrystalline MgO(001) tunneling barriers grown on amorphous CoFeB electrode
Authors: Mizuguchi M. , Suzuki Y. , Nagahama T. , Yuasa S.
Published: July 2007

Topological surface analysis using in situ scanning tunneling microscopy was performed for highly oriented polycrystalline (textured) MgO(001) tunneling barrier layers grown on amorphous CoFeB electrode layers. The microscopy revealed a MgO surface structure in which nanosized grains were dispersed on clusters that originated from the CoFeB underlayer. In situ annealing reduced this surface roughness. Local tunneling spectroscopy measurements revealed the formation of a nearly perfect and uniform tunneling barrier in spite of grain boundaries in the textured MgO(001) layer, which is consistent with the fact that textured CoFeB∕MgO∕CoFeB and fully epitaxial MgO-based magnetic tunnel junctions exhibit comparable spin-dependent tunneling properties.
Highly selective and low damage atomic layer etching of InP∕InAlAs heterostructures for high electron mobility transistor fabrication
Authors: Park S. D. , Oh C. K. , Lim W. S. , Lee H. C. , Bae J. W. , Yeom G. Y. , Kim T. W. , Song J. I. , Jang J. H.
Published: July 2007

Highly selective, low damage atomic layer etching (ALET) technology was developed for dry gate recess during the fabrication of InGaAs∕InP∕InAlAs high electron mobility transistors lattice matched to InP substrates. Etching characteristics of InP layer on top of InAlAs layer and the surface chemistry of the exposed InAlAs layer were investigated by utilizing angular resolved x-ray photoelectron spectroscopy. Finally, InAlAs Schottky diodes were fabricated by utilizing chlorine-based ALET technology and conventional Ar-based dry recess and their electrical characteristics were compared. By using the ALET, the etch selectivity as high as 70:1 was achieved for InP over InAlAs heterostructures and the stoichiometric modification of InAlAs was observed to be negligible after the recess etch process. Schottky diodes fabricated after the ALET exhibited the lower ideality factor and the higher Schottky barrier height compared to those fabricated with Ar-based plasma etching.
Multiplexed electrospray deposition for protein microarray with micromachined silicon device
Authors: Bhatnagar Parijat
Published: July 2007

Multiplexed electrospray deposition device capable of delivering picoliter volumes made by silicon micromachining technology has been developed as a deposition tool for making protein microarrays in a noncontact mode. Upon application of potential difference in the range of 7–9kV, biomolecules dissolved in suitable buffer with nonionic surfactant and loaded on the electrospray tips were dispensed on the substrate with microfabricated hydrogel features (1–10μm) in cone-jet mode. Schiff base chemistry followed by reductive amination was utilized for covalent immobilization.
Deep-sea vent ε-proteobacterial genomes provide insights into emergence of pathogens
Authors: Nakagawa Satoshi , Takaki Yoshihiro , Shimamura Shigeru , Reysenbach Anna-Louise , Takai Ken , Horikoshi Koki
Published: July 2007

Deep-sea vents are the light-independent, highly productive ecosystems driven primarily by chemolithoautotrophic microorganisms, in particular by ε-Proteobacteria phylogenetically related to important pathogens. We analyzed genomes of two deep-sea vent ε-Proteobacteria strains,
Sulfurovum
sp. NBC37-1 and
Nitratiruptor
sp. SB155-2, which provide insights not only into their unusual niche on the seafloor, but also into the origins of virulence in their pathogenic relatives,
Helicobacter
and
Campylobacter
species. The deep-sea vent ε-proteobacterial genomes encode for multiple systems for respiration, sensing and responding to environment, and detoxifying heavy metals, reflecting their adaptation to the deep-sea vent environment. Although they are nonpathogenic, both deep-sea vent ε-Proteobacteria share many virulence genes with pathogenic ε-Proteobacteria, including genes for virulence factor MviN, hemolysin, invasion antigen CiaB, and the
N
-linked glycosylation gene cluster. In addition, some virulence determinants (such as the H
2
-uptake hydrogenase) and genomic plasticity of the pathogenic descendants appear to have roots in deep-sea vent ε-Proteobacteria. These provide ecological advantages for hydrothermal vent ε-Proteobacteria who thrive in their deep-sea habitat and are essential for both the efficient colonization and persistent infections of their pathogenic relatives. Our comparative genomic analysis suggests that there are previously unrecognized evolutionary links between important human/animal pathogens and their nonpathogenic, symbiotic, chemolithoautotrophic deep-sea relatives.
CCR6-dependent recruitment of blood phagocytes is necessary for rapid CD4 T cell responses to local bacterial infection
Authors: Ravindran Rajesh , Rusch Lori , Itano Andrea , Jenkins Marc K. , McSorley Stephen J.
Published: July 2007

The contribution of CCR6 and phagocyte recruitment to the initiation of T cell responses to a local pathogen is unclear. CD4 T cell activation to an injected soluble antigen occurred rapidly and was completely CCR6-independent. In marked contrast, the tempo of pathogen-specific CD4 T cell activation depended on whether the antigen was secreted or cell-associated. Furthermore, lymph node pathogen-specific CD4 T cell activation required CCR6 and cell migration from the site of infection. Surprisingly, adoptive transfer of wild-type blood phagocytes rescued bacteria-specific T cell activation in CCR6-deficient mice, even when these cells were unable to participate in direct antigen presentation. These data demonstrate that T cell responses to a local bacterial infection follow a distinct tempo, largely determined by bacterial protein secretion, and that CCR6-mediated blood phagocyte recruitment to the site of infection is a critical step in the initiation of pathogen-specific immune responses in skin draining lymph nodes.
Methane monooxygenase gene expression mediated by methanobactin in the presence of mineral copper sources
Authors: Knapp Charles W. , Fowle David A. , Kulczycki Ezra , Roberts Jennifer A. , Graham David W.
Published: July 2007

Methane is a major greenhouse gas linked to global warming; however, patterns of
in situ
methane oxidation by methane-oxidizing bacteria (methanotrophs), nature's main biological mechanism for methane suppression, are often inconsistent with laboratory predictions. For example, one would expect a strong relationship between methanotroph ecology and Cu level because methanotrophs require Cu to sustain particulate methane monooxygenase (pMMO), the most efficient enzyme for methane oxidation. However, no correlation has been observed in nature, which is surprising because methane monooxygenase (MMO) gene expression has been unequivocally linked to Cu availability. Here we provide a fundamental explanation for this lack of correlation. We propose that MMO expression in nature is largely controlled by solid-phase Cu geochemistry and the relative ability of Cu acquisition systems in methanotrophs, such as methanobactins (mb), to obtain Cu from mineral sources. To test this hypothesis, RT-PCR expression assays were developed for
Methylosinus trichosporium
OB3b (which produces mb) to quantify pMMO, soluble MMO (the alternate MMO expressed when Cu is “unavailable”), and 16S-rRNA gene expression under progressively more stringent Cu supply conditions. When Cu was provided as CuCl
2
, pMMO transcript levels increased significantly consistent with laboratory work. However, when Cu was provided as Cu-doped iron oxide, pMMO transcript levels increased only when mb was also present. Finally, when Cu was provided as Cu-doped borosilicate glass, pMMO transcription patterns varied depending on the ambient mb:Cu supply ratio. Cu geochemistry clearly influences MMO expression in terrestrial systems, and, as such, local Cu mineralogy might provide an explanation for methane oxidation patterns in the natural environment.
A GeneTrek analysis of the maize genome
Authors: Liu Renyi , Vitte Clémentine , Ma Jianxin , Mahama A. Assibi , Dhliwayo Thanda , Lee Michael , Bennetzen Jeffrey L.
Published: July 2007

Analysis of the sequences of 74 randomly selected BACs demonstrated that the maize nuclear genome contains ≈37,000 candidate genes with homologues in other plant species. An additional ≈5,500 predicted genes are severely truncated and probably pseudogenes. The distribution of genes is uneven, with ≈30% of BACs containing no genes. BAC gene density varies from 0 to 7.9 per 100 kb, whereas most gene islands contain only one gene. The average number of genes per gene island is 1.7. Only 72% of these genes show collinearity with the rice genome. Particular LTR retrotransposon families (e.g.,
Gyma
) are enriched on gene-free BACs, most of which do not come from pericentromeres or other large heterochromatic regions. Gene-containing BACs are relatively enriched in different families of LTR retrotransposons (e.g.,
Ji
). Two major bursts of LTR retrotransposon activity in the last 2 million years are responsible for the large size of the maize genome, but only the more recent of these is well represented in gene-containing BACs, suggesting that LTR retrotransposons are more efficiently removed in these domains. The results demonstrate that sample sequencing and careful annotation of a few randomly selected BACs can provide a robust description of a complex plant genome.
A sound element gets lost in perceptual competition
Authors: Shinn-Cunningham Barbara G. , Lee Adrian K. C. , Oxenham Andrew J.
Published: July 2007

Our ability to understand auditory signals depends on properly separating the mixture of sound arriving from multiple sources. Sound elements tend to belong to only one object at a time, consistent with the principle of disjoint allocation, although there are instances of duplex perception or coallocation, in which two sound objects share one sound element. Here we report an effect of “nonallocation,” in which a sound element “disappears” when two ongoing objects compete for its ownership. When a target tone is presented either as one of a sequence of tones or simultaneously with a harmonic vowel complex, it is heard as part of the corresponding object. However, depending on the spatial configuration of the scene, if the target, the tones, and the vowel are all presented together, the target may not be perceived in either the tones or the vowel, even though it is not perceived as a separate entity. This finding suggests an asymmetry in the strength of the perceptual evidence required to reject vs. to include an element within the auditory foreground, a result with important implications for how we process complex auditory scenes containing ambiguous information.
Infection and coaccumulation of tobacco mosaic virus proteins alter microRNA levels, correlating with symptom and plant development
Authors: Bazzini A. A. , Hopp H. E. , Beachy R. N. , Asurmendi S.
Published: July 2007

Infections by plant virus generally cause disease symptoms by interfering with cellular processes. Here we demonstrated that infection of
Nicotiana tabacum
(
N.t
) by plant viruses representative of the
Tobamoviridae
,
Potyviridae
, and
Potexviridae
families altered accumulation of certain microRNAs (miRNAs). A correlation was observed between symptom severity and alteration in levels of miRNAs 156, 160, 164,166, 169, and 171 that is independent of viral posttranscriptional gene silencing suppressor activity. Hybrid transgenic plants that produced tobacco mosaic virus (TMV) movement protein (MP) plus coat protein (CP)
T42W
(a variant of CP) exhibited disease-like phenotypes, including abnormal plant development. Grafting studies with a plant line in which both transgenes are silenced confirmed that the disease-like phenotypes are due to the coexpression of CP and MP. In hybrid MPxCP
T42W
plants and TMV-infected plants, miRNAs 156, 164, 165, and 167 accumulated to higher levels compared with nontransgenic and noninfected tissues. Bimolecular fluorescence complementation assays revealed that MP interacts with CP
T42W
in vivo
and leads to the hypothesis that complexes formed between MP and CP caused increases in miRNAs that result in disease symptoms. This work presents evidence that virus infection and viral proteins influence miRNA balance without affecting posttranscriptional gene silencing and contributes to the hypothesis that viruses exploit miRNA pathways during pathogenesis.
Observation of sequential steps in the folding of intestinal fatty acid binding protein using a slow folding mutant and19F NMR
Authors: Li Hua , Frieden Carl
Published: July 2007

The rat intestinal fatty acid binding protein (IFABP) primarily comprises two β-sheet structures surrounding a large internal cavity. The urea denatured WT protein folds within seconds after dilution to nondenaturing conditions. Replacing a glycine with valine in the turn between the last two β-strands (Gly121Val) slows the folding process by more than three orders of magnitude. After incorporating 4-19F-phenylalanine into the mutant protein, we were able to directly monitor the behavior of the eight phenylalanine side chains in real time during folding using19F NMR. Specifically, there is a nonnative-like collapse in regions involving three phenylalanine residues (Phe-62, Phe-68, and Phe-93) within milliseconds. At least two distinct NMR peaks were observed, suggesting conformational fluctuations in this region. Formation of this site is followed by formation of native structure of Phe-2 and Phe-17, then by Phe-47, and finally by the cooperative rearrangement of the intermediate structures to the final native structure. It is proposed that the Gly121Val mutation slows the formation of a normal nucleating site, not only slowing overall folding, but also allowing intermediates in regions distant from the mutation to be experimentally observed. Because intermediates involved in protein folding are normally difficult to observe due to their marginal stability, the experimental approach used here may serve as a general method for determining the nature of both early and late steps in protein folding.
Habermas and Iranian Intellectuals
Authors: Paya Ali , Ghaneirad Mohammad Amin
Published: July 2007

In this paper, we discuss the impact of Jürgen Habermas' ideas on Iranian intellectuals who live in Iran. The upshot of the paper is that in present day Iran, where the society is going through a significant transitional period, various intellectual groups have reacted differently towards the ideas of the German philosopher-sociologist. While the orthodox left-wing (ex-Marxist) intellectuals and the conservative right-wing writers have, by and large, tended to ignore his views, a younger generation of the left-wing intellectuals and a number of the Muslim intellectuals with left-wing/socialist tendencies, have tried, each in their own ways, to ‘adopt’ Habermas' ideas in pursuit of their own projects/research programs.
Rain Making Ceremonies in Iran
Authors: Başgöz Mehmet Ilhan
Published: July 2007

Pre-Islamic beliefs and practices abound in Iran, albeit with an Islamic veneer, have been entirely islamicized. One kind of such surviving practices is that of rain making ceremonies. In this article, seven major rain-making ceremonies are categorized, described, and interpreted, including some regional variants thereof. Attention is paid to the fact that these ceremonies are not limited to Iran, but are also found in neighboring countries (Iraq, Turkey, India, Central Asia), thus showing that these are all survivors of common ancient religious archetypes.
Cross‐cultural Differences In Beliefs And Practices That Affect The Language Spoken To Children: mothers With Indian And Western Heritage
Authors: Simmons Noreen , Johnston Judith
Published: July 2007

Background: Speech–language pathologists often advise families about interaction patterns that will facilitate language learning. This advice is typically based on research with North American families of European heritage and may not be culturally suited for non‐Western families.

Aims: The goal of the project was to identify differences in the beliefs and practices of Indian and Euro‐Canadian mothers that would affect patterns of talk to children.

Methods & Procedures: A total of 47 Indian mothers and 51 Euro‐Canadian mothers of preschool age children completed a written survey concerning child‐rearing practices and beliefs, especially those about talk to children.

Outcomes & Results: Discriminant analyses indicated clear cross‐cultural differences and produced functions that could predict group membership with a 96% accuracy rate. Items contributing most to these functions concerned the importance of family, perceptions of language learning, children's use of language in family and society, and interactions surrounding text.

Conclusions: Speech–language pathologists who wish to adapt their services for families of Indian heritage should remember the centrality of the family, the likelihood that there will be less emphasis on early independence and achievement, and the preference for direct instruction.
Differentiating Normal Variability From Inconsistency In Children'S Speech: normative Data
Authors: Holm Alison , Crosbie Sharon , Dodd Barbara
Published: July 2007

Background: In young, typically developing children, some word production variability is expected, but highly inconsistent speech is considered a clinical marker for disorder. Speech–language pathologists need to identify variability versus inconsistency, yet these terms are not clearly differentiated. Not only is it important to identify inconsistency, but also it needs to be defined and measured so that clinical decisions are evidence based. In order to understand inconsistent speech production, typical variability must be described.

Aims: This paper differentiates between variability and inconsistent productions. Variability is defined as productions that differ, but can be attributed to factors described in normal acquisition and use of speech. Inconsistency is speech characterized by a high proportion of differing repeated productions with multiple error types, both segmental (phoneme) and structural errors (consonant–vowel sequence within a syllable). The study describes and quantifies the consistency of word production in typically developing children aged between 3;0 and 6;11 years.

Methods and Procedures: This paper reports a large cross‐sectional study (n = 409) of the consistency of children's production of words within the same linguistic context.

Outcomes and Results: The study found that the speech of typically developing children is highly consistent. Children in the youngest age group demonstrated the highest levels of variability, but it remained below 13% with 10% reflecting maturational influences.

Conclusions: Inconsistent production cannot be considered a typical feature of speech development. The results inform differential diagnosis of speech disorder.