Modelling cell separation during plant organ abscission

A simple mathematical model is presented to describe the cell separation process that plants undertake in order to deliberately shed organs. The focus here is on modelling the production of the enzyme polygalacturonase, which breaks down pectin that provides natural cell-to-cell adhesion in the localised abscission zone. A coupled system of three ordinary differential equations is given for a single cell, and then extended to hold for a layer of cells in the abscission zone. Simple observations are made based on the results of this preliminary model and, furthermore, a number of opportunities for applied mathematicians to make contributions in this subject area are discussed.

Adolescent pedometer protocols : examining reactivity, tampering and participants' perceptions

The aim of this study was to investigate adolescents' potential reactivity and tampering while wearing pedometers by comparing different monitoring protocols to accelerometer output. The sample included adolescents (N=123, age range=14-15 years) from three secondary schools in New South Wales, Australia. Schools were randomised to one of the three pedometer monitoring protocols: (i) daily sealed (DS) pedometer group, (ii) unsealed (US) pedometer group or (iii) weekly sealed (WS) pedometer group. Participants wore pedometers (Yamax Digi-Walker CW700, Yamax Corporation, Kumamoto City, Japan) and accelerometers (Actigraph GT3X+, Pensacola, USA) simultaneously for seven days. Repeated measures analysis of variance was used to examine potential reactivity. Bivariate correlations between step counts and accelerometer output were calculated to explore potential tampering. The correlation between accelerometer output and pedometer steps/day was strongest among participants in the WS group (r=0.82, P <= 0.001), compared to the US (r=0.63, P <= 0.001) and DS (r=0.16, P=0.324) groups. The DS (P <= 0.001) and US (P=0.003), but not the WS (P=0.891), groups showed evidence of reactivity. The results suggest that reactivity and tampering does occur in adolescents and contrary to existing research, pedometer monitoring protocols may influence participant behaviour.

Using objective physical activity measures with youth : How many days of monitoring are needed?

Purpose The purpose of this study was to establish the minimal number of days of monitoring required for accelerometers to assess usual physical activity in children. Methods A total of 381 students (189 M, 192 F) wore a CSA 7164 uniaxial accelerometer for seven consecutive days. To examine age-related trends students were grouped as follows: Group I: grades 1-3 (N = 92); Group II: grades 4-6 (N = 98); Group III: grades 7-9 (N = 97); Group IV: grades 10-12 (N = 94). Average daily time spent in moderate-to-vigorous physical activity (MVPA) was calculated from minute-by-minute activity counts using the regression equation developed by Freedson et al. (1997). Results Compared with adolescents in grades 7 to 12, children in grades 1 to 6 exhibited less day-to-day variability in MVPA behavior. Spearman-Brown analysts indicated that between 4 and 5 d of monitoring would be necessary to a achieve a reliability of 0.80 in children, and between 8 and 9 d of monitoring would be necessary to achieve a reliability of 0.80 in adolescents. Within all grade levels, the 7-d monitoring protocol produced acceptable estimates of daily participation in MVPA (R = 0.76 (0.71-0.81) to 0.87 (0.84-0.90)). Compared with weekdays, children exhibited significantly higher levels of MVPA on weekends, whereas adolescents exhibited significantly lower levels of MVPA on weekends. Principal components analysis revealed two distinct time components for MVPA during the day for children (early morning, rest of the day), and three distinct time components for MVPA during the day for adolescents (morning, afternoon, early evening). Conclusions These results indicate that a 7-d monitoring protocol provides reliable estimates of usual physical activity behavior in children and adolescents and accounts for potentially important differences in weekend versus weekday activity behavior as well as differences in activity patterns within a given day.

UafB is a serine-rich repeat adhesin of Staphylococcus saprophyticus that mediates binding to fibronectin, fibrinogen and human uroepithelial cells

Staphylococcus saprophyticus is an important cause of urinary tract infection (UTI), particularly among young women, and is second only to uropathogenic Escherichia coli as the most frequent cause of UTI. The molecular mechanisms of urinary tract colonization by S. saprophyticus remain poorly understood. We have identified a novel 6.84 kb plasmid-located adhesin-encoding gene in S. saprophyticus strain MS1146 which we have termed uro-adherence factor B (uafB). UafB is a glycosylated serine-rich repeat protein that is expressed on the surface of S. saprophyticus MS1146. UafB also functions as a major cell surface hydrophobicity factor. To characterize the role of UafB we generated an isogenic uafB mutant in S. saprophyticus MS1146 by interruption with a group II intron. The uafB mutant had a significantly reduced ability to bind to fibronectin and fibrinogen. Furthermore, we show that a recombinant protein containing the putative binding domain of UafB binds specifically to fibronectin and fibrinogen. UafB was not involved in adhesion in a mouse model of UTI; however, we observed a striking UafB-mediated adhesion phenotype to human uroepithelial cells. We have also identified genes homologous to uafB in other staphylococci which, like uafB, appear to be located on transposable elements. Thus, our data indicate that UafB is a novel adhesin of S. saprophyticus that contributes to cell surface hydrophobicity, mediates adhesion to fibronectin and fibrinogen, and exhibits tropism for human uroepithelial cells.

Histopathological features of bone regeneration in a canine segmental ulnar defect model

Background Today, finding an ideal biomaterial to treat the large bone defects, delayed unions and non-unions remains a challenge for orthopaedic surgeions and researchers. Several studies have been carried out on the subject of bone regeneration, each having its own advantages. The present study has been designed in vivo to evaluate the effects of cellular auto-transplantation of tail vertebrae on healing of experimental critical bone defect in a dog model. Methods Six indigenous breeds of dog with 32 ± 3.6 kg average weight from both sexes (5 males and 1 female) received bilateral critical-sized ulnar segmental defects. After determining the health condition, divided to 2 groups: The Group I were kept as control I (n = 1) while in Group II (experimental group; n = 5) bioactive bone implants were inserted. The defects were implanted with either autogeneic coccygeal bone grafts in dogs with 3-4 cm diaphyseal defects in the ulna. Defects were stabilized with internal plate fixation, and the control defects were not stabilized. Animals were euthanized at 16 weeks and analyzed by histopathology. Results Histological evaluation of this new bone at sixteen weeks postoperatively revealed primarily lamellar bone, with the formation of new cortices and normal-appearing marrow elements. And also reformation cortical compartment and reconstitution of marrow space were observed at the graft-host interface together with graft resorption and necrosis responses. Finally, our data were consistent with the osteoconducting function of the tail autograft. Conclusions Our results suggested that the tail vertebrae autograft seemed to be a new source of autogenous cortical bone in order to supporting segmental long bone defects in dogs. Furthermore, cellular autotransplantation was found to be a successful replacement for the tail vertebrae allograft bone at 3-4 cm segmental defects in the canine mid- ulna. Clinical application using graft expanders or bone autotransplantation should be used carefully and requires further investigation.

Students' responses to the RACQ docudrama program

Young people are over-represented in road crashes and school-based education programs, including the RACQ Docudrama program, represent initiatives aimed at improving road safety among this high-risk group. The aim of the study was to apply an extended Theory of Planned Behaviour framework to understand more about the extent to which the program influenced individuals‟ intentions to speak up to a driver engaging in risky behaviours (e.g., speeding). Senior high school students (N=260) from 5 Queensland schools completed a survey in class. The study included a Control group (n = 86) who responded to the survey prior to completing the Docudrama program and an Intervention group comprising an Intervention-Immediate (n=100) and an Intervention-Delayed group (n = 74) who completed the survey after having participated in the program either on the day or up to a week later, respectively. Overall, the findings provided support for the beneficial effects of the program. Some of the study’s key findings included: (i) Intervention group participants consistently reported significantly stronger intentions to speak up than participants in the control group; (ii) among the significant predictors of intentions, a notable finding was that the more individuals anticipated feeling regretful for not having spoken up to a risky driver, the stronger their intentions were to speak up, and; (iii) the level of fear reported by students significantly decreased and was lowest at the conclusion of the program, following facilitated group discussion. The implications of the results for future research, program development and practice are discussed.

Randomized phase II trial of the efficacy and safety of trastuzumab combined with docetaxel in patients with human epidermal growth factor receptor 2-positive metastatic breast cancer administered as first-line treatment : the M77001 study group

Purpose: This randomized, multicenter trial compared first-line trastuzumab plus docetaxel versus docetaxel alone in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC). Patients and Methods: Patients were randomly assigned to six cycles of docetaxel 100 mg/m 2 every 3 weeks, with or without trastuzumab 4 mg/kg loading dose followed by 2 mg/kg weekly until disease progression. Results: A total of 186 patients received at least one dose of the study drug. Trastuzumab plus docetaxel was significantly superior to docetaxel alone in terms of overall response rate (61% v 34%; P = .0002), overall survival (median, 31.2 v 22.7 months; P = .0325), time to disease progression (median, 11.7 v 6.1 months; P = .0001), time to treatment failure (median, 9.8 v 5.3 months; P = .0001), and duration of response (median, 11.7 v 5.7 months; P = .009). There was little difference in the number and severity of adverse events between the arms. Grade 3 to 4 neutropenia was seen more commonly with the combination (32%) than with docetaxel alone (22%), and there was a slightly higher incidence of febrile neutropenia in the combination arm (23% v 17%). One patient in the combination arm experienced symptomatic heart failure (1%). Another patient experienced symptomatic heart failure 5 months after discontinuation of trastuzumab because of disease progression, while being treated with an investigational anthracycline for 4 months. Conclusion: Trastuzumab combined with docetaxel is superior to docetaxel alone as first-line treatment of patients with HER2-positive MBC in terms of overall survival, response rate, response duration, time to progression, and time to treatment failure, with little additional toxicity. © 2005 by American Society of Clinical Oncology.

Amino group position dependent orientation of self-assembled monomolecular films of tetraaminophthalocyanatocobalt(II) on Au surfaces

Self-assembled monomolecular films of 1,8,15,22-tetraaminophthalocyanatocobalt(II) (4α-CoIITAPc) and 2,9,16,23-tetraaminophthalocyanatocobalt(II) (4β-CoIITAPc) on Au surfaces were prepared by spontaneous adsorption from solution. These films were characterized by cyclic voltammetry and Raman spectroscopy. Both the surface coverage (Γ) and intensity of the in-plane stretching bands obtained from Raman studies vary for these monomolecular films, indicating different orientations adopted by them on Au surfaces. The 4α-CoIITAPc-modified electrode exhibits an E1/2 of 0.35 V, while the 4β-CoIITAPc-modified electrode exhibits an E1/2 of 0.19 V, corresponding to the CoII/CoIII redox couple in 0.1 M H2SO4. The Γ estimated from the charge associated with the oxidation of Co(II) gives (2.62 ± 0.10) × 10-11 mol cm-2 for 4α-CoIITAPc and (3.43 ± 0.14) × 10-10 mol cm-2 for 4β-CoIITAPc. In Raman spectral studies, the intensity ratio between in-plane phthalocyanine (Pc) stretching and the Au−N stretching was found to be 6.6 for 4β-CoIITAPc, while it was 1.6 for 4α-CoIITAPc. The obtained lower Γ and intensity ratio values suggest that 4α-CoIITAPc adopts nearly a parallel orientation on the Au surface, while the higher Γ and intensity ratio values suggest that 4β-CoIITAPc adopts a perpendicular orientation. The electrochemical reduction of dioxygen was carried out using these differently oriented Pc's in phosphate buffer solution (pH 7.2). Both the Pc's catalyze the reduction of dioxygen; however, the 4α-CoIITAPc-modified electrode greatly reduces the dioxygen reduction overpotential compared to 4β-CoIITAPc-modified and bare Au electrodes.

A phase II trial of brivanib in recurrent or persistent endometrial cancer: An NRG oncology/gynecologic oncology group study

PURPOSE Brivanib, an oral, multi-targeted tyrosine kinase inhibitor with activity against vascular endothelial growth factor (VEGF) and fibroblast growth factor receptor (FGFR) was investigated as a single agent in a phase II trial to assess the activity and tolerability in recurrent or persistent endometrial cancer (EMC). PATIENTS AND METHODS Eligible patients had persistent or recurrent EMC after receiving one to two prior cytotoxic regimens, measurable disease, and performance status of ≤2. Treatment consisted of brivanib 800 mg orally every day until disease progression or prohibitive toxicity. Primary endpoints were progression-free survival (PFS) at six months and objective tumor response. Expression of multiple angiogenic proteins and FGFR2 mutation status was assessed. RESULTS Forty-five patients were enrolled. Forty-three patients were eligible and evaluable. Median age was 64 years. Twenty-four patients (55.8%) received prior radiation. Median number of cycles was two (range 1-24). No GI perforations but one rectal fistula were seen. Nine patients had grade 3 hypertension, with one experiencing grade 4 confusion. Eight patients (18.6%; 90% CI 9.6%-31.7%) had responses (one CR and seven PRs), and 13 patients (30.2%; 90% CI 18.9%-43.9%) were PFS at six months. Median PFS and overall survival (OS) were 3.3 and 10.7 months, respectively. When modeled jointly, VEGF and angiopoietin-2 expression may diametrically predict PFS. Estrogen receptor-α (ER) expression was positively correlated with OS. CONCLUSION Brivanib is reasonably well tolerated and worthy of further investigation based on PFS at six months in recurrent or persistent EMC.

Three-dimensional hydrogen-bonded structures in the 1:1 proton-transfer compounds of L-tartaric acid with the associative-group monosubstituted pyridines 3-minopyridine, 3-carboxypyridine (nicotinic acid) and 2-carboxypyridine (picolinic acid).

The 1:1 proton-transfer compounds of L-tartaric acid with 3-aminopyridine [3-aminopyridinium hydrogen (2R,3R)-tartrate dihydrate, C5H7N2+·C4H5O6-·2H2O, (I)], pyridine-3-carboxylic acid (nicotinic acid) [anhydrous 3-carboxypyridinium hydrogen (2R,3R)-tartrate, C6H6NO2+·C4H5O6-, (II)] and pyridine-2-carboxylic acid [2-carboxypyridinium hydrogen (2R,3R)-tartrate monohydrate, C6H6NO2+·C4H5O6-·H2O, (III)] have been determined. In (I) and (II), there is a direct pyridinium-carboxyl N+-HO hydrogen-bonding interaction, four-centred in (II), giving conjoint cyclic R12(5) associations. In contrast, the N-HO association in (III) is with a water O-atom acceptor, which provides links to separate tartrate anions through Ohydroxy acceptors. All three compounds have the head-to-tail C(7) hydrogen-bonded chain substructures commonly associated with 1:1 proton-transfer hydrogen tartrate salts. These chains are extended into two-dimensional sheets which, in hydrates (I) and (III) additionally involve the solvent water molecules. Three-dimensional hydrogen-bonded structures are generated via crosslinking through the associative functional groups of the substituted pyridinium cations. In the sheet struture of (I), both water molecules act as donors and acceptors in interactions with separate carboxyl and hydroxy O-atom acceptors of the primary tartrate chains, closing conjoint cyclic R44(8), R34(11) and R33(12) associations. Also, in (II) and (III) there are strong cation carboxyl-carboxyl O-HO hydrogen bonds [OO = 2.5387 (17) Å in (II) and 2.441 (3) Å in (III)], which in (II) form part of a cyclic R22(6) inter-sheet association. This series of heteroaromatic Lewis base-hydrogen L-tartrate salts provides further examples of molecular assembly facilitated by the presence of the classical two-dimensional hydrogen-bonded hydrogen tartrate or hydrogen tartrate-water sheet substructures which are expanded into three-dimensional frameworks via peripheral cation bifunctional substituent-group crosslinking interactions.

The structure of the copper(II) complex with 4,5-dichlorophthalic acid: The 1:1 complex 'adduct' salt trans-tetraaqua(2-carboxy-4,5-dichlorobenzoato)(4,5-dichlorobenzene-1,2-dicarboxylic acid)copper(II) 2-carboxy-4,5-dichlorobenzoate

The unusual (1:1) complex ‘adduct’ salt of copper(II) with 4,5-dichlorophthalic acid (H2DCPA), having formula [Cu(H2O)4(C8H3Cl2O4) (C8H4Cl2O4)] . (C8H3Cl2O4) has been synthesized and characterized using single-crystal X-ray diffraction. Crystals are monoclinic, space group P21/c, with Z = 4 in a cell with dimensions a = 20.1376(7), b =12.8408(4) c = 12.1910(4) Å, β = 105.509(4)o. The complex is based on discrete tetragonally distorted octahedral [CuO6] coordination centres with the four water ligands occupying the square planar sites [Cu-O, 1.962(4)-1.987(4) Å] and the monodentate carboxyl-O donors of two DCPA ligand species in the axial sites. The first of these bonds [Cu-O, 2.341(4) Å] is with an oxygen of a HDCPA monoanion, the second with an oxygen of a H2DCPA acid species [Cu-O, 2.418(4) Å]. The un-coordinated ‘adduct’ molecule is a HDCPA counter anion which is strongly hydrogen-bonded to the coordinated H2DCPA ligand [O… O, 2.503(6) Å] while a number of peripheral intra- and intermolecular hydrogen-bonding interactions give a two-dimensional network structure.

Spectroscopy of selected copper group minerals : chalcophyllite and chenevixite-implications for hydrogen bonding

NIR and IR spectroscopy has been applied for detection of chemical species and the nature of hydrogen bonding in arsenate complexes. The structure and spectral properties of copper(II) arsenate minerals chalcophyllite and chenevixite are compared with copper(II) sulphate minerals devilline, chalcoalumite and caledonite. Split NIR bands in the electronic spectrum of two ranges 11700-8500 cm-1 and 8500-7200 cm-1 confirm distortion of octahedral symmetry for Cu(II) in the arsenate complexes. The observed bands with maxima at 9860 and 7750 cm-1 are assigned to Cu(II) transitions 2B1g ® 2B2g and 2B1g ® 2A1g. Overlapping bands in the NIR region 4500-4000 cm-1 is the effect of multi anions OH-, (AsO4)3- and (SO4)2-. The observation of broad and diffuse bands in the range 3700-2900 cm-1 confirms strong hydrogen bonding in chalcophyllite relative to chenevixite. The position of the water bending vibrations indicates the water is strongly hydrogen bonded in the mineral structure. The strong absorption feature centred at 1644 cm-1 in chalcophyllite indicates water is strongly hydrogen bonded in the mineral structure. The H2O-bending vibrations shift to low wavenumbers in chenevixite and an additional band observed at 1390 cm-1 is related to carbonate impurity. The characterisation of IR spectra by ν3 antisymmetric stretching vibrations of (SO4)2- and (AsO4)3 ions near 1100 and 800 cm-1 respectively is the result of isomorphic substitution for arsenate by sulphate in both the minerals of chalcophyllite and chenevixite.

Spectroscopy of selected copper group minerals : Ktenasite, orthoserpierite and Kipushite

The near-infrared (NIR) and infrared (IR) spectroscopy has been applied for characterisation of three complex Cu-Zn sulphate/phosphate minerals, namely ktenasite, orthoserpierite and kipushite. The spectral signatures of the three minerals are quite distinct in relation to their composition and structure. The effect of structural cations substitution (Zn2+ and Cu2+) on band shifts is significant both in the electronic and vibrational spectra of these Cu-Zn minerals. The variable Cu:Zn ratio between Zn-rich and Cu-rich compositions shows a strong effect on Cu(II) bands in the electronic spectra. The Cu(II) spectrum is most significant in kipushite (Cu-rich) with bands displayed at high wavenumbers at11390 and 7545 cm-1. The isomorphic substitution of Cu2+ for Zn2+ is reflected in the NIR and IR spectroscopic signatures. The multiple bands for 3 and 4 (SO4)2- stretching vibrations in ktenasite and orthoserpierite are attributed to the reduction of symmetry to the sulphate ion from Td to C2V. The IR spectrum of kipushite is characterised by strong (PO4)3- vibrational modes at 1090 and 990 cm-1. The range of IR absorption is higher in Ktenasite than in kipushite while it is intermediate in orthoserpierite.

Long term immunity to live attenuated Japanese encephalitis chimeric virus vaccine : randomized, double-blind, 5-year phase II study in healthy adults.

In a randomized, double-blind study, 202 healthy adults were randomized to receive a live, attenuated Japanese encephalitis chimeric virus vaccine (JE-CV) and placebo 28 days apart in a cross-over design. A subgroup of 98 volunteers received a JE-CV booster at month 6. Safety, immunogenicity, and persistence of antibodies to month 60 were evaluated. There were no unexpected adverse events (AEs) and the incidence of AEs between JE-CV and placebo were similar. There were three serious adverse events (SAE) and no deaths. A moderately severe case of acute viral illness commencing 39 days after placebo administration was the only SAE considered possibly related to immunization. 99% of vaccine recipients achieved a seroprotective antibody titer ≥ 10 to JE-CV 28 days following the single dose of JE-CV, and 97% were seroprotected at month 6. Kaplan Meier analysis showed that after a single dose of JE-CV, 87% of the participants who were seroprotected at month 6 were still protected at month 60. This rate was 96% among those who received a booster immunization at month 6. 95% of subjects developed a neutralizing titer ≥ 10 against at least three of the four strains of a panel of wild-type Japanese encephalitis virus (JEV) strains on day 28 after immunization. At month 60, that proportion was 65% for participants who received a single dose of JE-CV and 75% for the booster group. These results suggest that JE-CV is safe, well tolerated and that a single dose provides long-lasting immunity to wild-type strains

Concomitant or sequential administration of live attenuated Japanese encephalitis chimeric virus vaccine and yellow fever 17D vaccine : randomized double-blind phase II evaluation of safety and immunogenicity

A randomized, double-blind, study was conducted to evaluate the safety, tolerability and immunogenicity of a live attenuated Japanese encephalitis chimeric virus vaccine (JE-CV) co-administered with live attenuated yellow fever (YF) vaccine (YF-17D strain; Stamaril(®), Sanofi Pasteur) or administered successively. Participants (n = 108) were randomized to receive: YF followed by JE-CV 30 days later, JE followed by YF 30 days later, or the co-administration of JE and YF followed or preceded by placebo 30 days later or earlier. Placebo was used in a double-dummy fashion to ensure masking. Neutralizing antibody titers against JE-CV, YF-17D and selected wild-type JE virus strains was determined using a 50% serum-dilution plaque reduction neutralization test. Seroconversion was defined as the appearance of a neutralizing antibody titer above the assay cut-off post-immunization when not present pre-injection at day 0, or a least a four-fold rise in neutralizing antibody titer measured before the pre-injection day 0 and later post vaccination samples. There were no serious adverse events. Most adverse events (AEs) after JE vaccination were mild to moderate in intensity, and similar to those reported following YF vaccination. Seroconversion to JE-CV was 100% and 91% in the JE/YF and YF/JE sequential vaccination groups, respectively, compared with 96% in the co-administration group. All participants seroconverted to YF vaccine and retained neutralizing titers above the assay cut-off at month six. Neutralizing antibodies against JE vaccine were detected in 82-100% of participants at month six. These results suggest that both vaccines may be successfully co-administered simultaneously or 30 days apart.