bluuebunny/crossref_metadata_2025 huggingface dataset:
Outcomes after Pylorus‐preserving Gastrectomy for Early Gastric Cancer: A Prospective Multicenter Trial
Authors: Shibata Chikashi , Shiiba Ken‐ichí , Funayama Yuji , Ishii Seiichi , Fukushima Kouhei , Mizoi Takayuki , Koyama Kaori , Miura Koh , Matsuno Seiki , Naito Hiroo , Kato Eiichi , Honda Tsuyohiko , Momono Satoshi , Ouchi Akio , Ashino Yoshikazu , Takahashi Yoshinobu , Fujiya Tsuneaki , Iwatsuki Akihiro , Sasaki Iwao
Published: September 2004

The aim of the present study was to compare in a prospective, multicenter trial the results early and late after pylorus‐preserving gastrectomy (PPG) versus conventional distal gastrectomy (CDG) with Billroth I anastomosis for early gastric cancer. Eighty‐one patients with early gastric cancer were randomized and then underwent either PPG or CDG. Duration of operation, intraoperative blood loss, days until removal of the nasogastric tube, days until start of oral intake, and decrease in body weight were studied as parameters for outcomes early after the surgery. Late results were studied in patients followed for longer than 3 years. Change in body weight, status of oral intake, symptoms suggesting early dumping syndrome, and overall satisfaction were addressed in the questionnaire. The presence of gallstones was examined with ultrasonography. There were no differences in early results between PPG and CDG. The incidence of early dumping syndrome was lower in PPG (8%) than in CDG (33%). Other late results including the incidence of gallstones were not different between the 2 groups. These results indicate that PPG is as safe as CDG and has an advantage in terms of early dumping syndrome.
Coupling effect of the equatorial F region irregularities on the low latitude E region instability processes
Authors: Patra A. K. , Sripathi S. , Tiwari D.
Published: September 2004

Simultaneous observations of E and F region irregularities made using the Gadanki MST radar are presented. The observations show that the E region echoes weaken or disappear during the growth phase of the topside F region irregularities. Unlike Jicamarca observations, no valley region echoes are observed during this phase. It is shown that the weakening or disappearance of E region signals are not directly coupled with the F region irregularities just overhead, but linked with the instability processes over the magnetic equator through the magnetic field lines. It is proposed that the fringe fields present in the valley region in association with the equatorial F region plasma bubbles, in the presence of appropriate background electric field conditions, are responsible candidates. It is shown that these fringe fields and the electric fields associated with the irregularities in the valley region can map to the low latitude E region and thereby inhibit the growth of the E region instability processes as revealed by the Gadanki radar observations.
Expression of matrix metalloproteinase‐9 in human platelets: regulation of platelet activation in in vitro and in vivo studies
Authors: Sheu Joen R , Fong Tsorng H , Liu Cheng M , Shen Ming Y , Chen Ta L , Chang Yi , Lu Meng S , Hsiao George
Published: September 2004

The aim of this study was to identify the presence of matrix metalloproteinase‐9 (MMP‐9) in human platelets and systematically examine its inhibitory mechanisms of platelet activation.

In this study, we report on an efficient method for the quantitative analysis of pro‐MMP‐9 in human platelets using capillary zone electrophoresis (CZE). To elucidate subcellular localization of MMP‐9 in human platelets, we investigated intraplatelet MMP‐9 by immunogold labeling and visualized it using electron microscopy. In an in vivo thrombotic study, platelet thrombus formation was induced by irradiation of mesenteric venules with filtered light in mice pretreated with fluorescein sodium.

MMP‐9‐gold labeling was observed on the plasma membrane, α‐granules, open canalicular system, and within the cytoplasma both in resting and activated platelets. Furthermore, activated MMP‐9 concentration‐dependently (15–90 ng ml−1) inhibited platelet aggregation stimulated by agonists. Activated MMP‐9 (21 and 90 ng ml−1) inhibited phosphoinositide breakdown, intracellular Ca2+ mobilization, and thromboxane A2 formation in human platelets stimulated by collagen (1 μg ml−1). In addition, activated MMP‐9 (21 and 90 ng ml−1) significantly increased the formation of nitric oxide/cyclic GMP.

Rapid phosphorylation of a platelet protein of Mr 47,000 (P47), a marker of protein kinase C activation, was triggered by phorbol‐12, 13‐dibutyrate (PDBu) (60 nM). This phosphorylation was markedly inhibited by activated MMP‐9 (21 and 90 ng ml−1). Activated MMP‐9 (1 μg g−1) significantly prolonged the latency period of inducing platelet plug formation in mesenteric venules.

These results indicate that the antiplatelet activity of activated MMP‐9 may be involved in the following pathways. (1) Activated MMP‐9 may inhibit the activation of phospholipase C, followed by inhibition of phosphoinositide breakdown, protein kinase C activation, and thromboxane A2 formation, thereby leading to inhibition of intracellular Ca2+ mobilization. (2) Activated MMP‐9 also activated the formation of nitric oxide/cyclic GMP, resulting in inhibition of platelet aggregation. These results strongly indicate that MMP‐9 is a potent inhibitor of aggregation. It may play an important role as a negative feedback regulator during platelet activation.

British Journal of Pharmacology (2004) 143, 193–201. doi:10.1038/sj.bjp.0705917
Investigation of structural and ferroelectric properties of pulsed-laser-ablated epitaxial Nd-doped bismuth titanate films
Authors: Garg A. , Snedden A. , Lightfoot P. , Scott J. F. , Hu X. , Barber Z. H.
Published: September 2004

Lanthanide doped bismuth titanate films have been shown to exhibit excellent fatigue resistance and higher remanent polarization than SrBi2Ta2O9 films. In this paper we report on the detailed investigation of structural and ferroelectric properties of Nd-doped Bi4Ti3O12 (BNdT) films grown by pulsed laser ablation. Highly epitaxial 300nm thick (001)-, (118)-, and (104)-oriented BNdT films were deposited on SrRuO3 buffered SrTiO3 substrates of (100), (110), and (111) orientations, respectively. The highest remanent polarization (2Pr) of ∼40μC∕cm2 was observed in the (104)-oriented films at a coercive field of ∼50kV∕cm. Leakage currents of the films were of the order of 10−6−10−5A∕cm2 with (104)-oriented films showing improved behavior. The films showed good fatigue resistance upon bipolar switching up to 109 cycles.
Oxygen precipitation in nitrogen doped Czochralski silicon wafers. II. Effects of nitrogen and oxygen coupling
Authors: Karoui A. , Rozgonyi G. A.
Published: September 2004

Nitrogen segregation and coprecipitation with oxygen in N-doped Czochralski (N-CZ) silicon wafers are investigated as a function of depth based on extended defect structure and chemical composition. High resolution nitrogen and oxygen secondary ion mass spectroscopy imaging revealed strong coupling of oxygen with nitrogen in annealed as well as in “as-grown” N-CZ Si wafers. In both cases, the near-surface regions appeared highly supersaturated in N and O forming a continuum of defects initiated by N-O complexes. The N and O stoichiometry depth profiles were found to depend on the material thermal history. The spatial variation of the stoichiometry ratio was also determined for precipitates using a combination of scanning transmission electron microscope (STEM) in Z-contrast mode with electron energy loss spectroscopy. The precipitate atomic and microstructures, analyzed by high resolution TEM and STEM, clearly demonstrate that second phase precipitate is precursor to a third phase that is an outer oxynitride shell. Nitrogen and oxygen cosegregation from the matrix to the precipitate interface occurs in a similar fashion as in the subsurface region. We propose a mechanism for oxygen precipitation in N-CZ Si based on N segregation to the interface while oxygen is trapped inside the oxynitride shell.
Analysis and determination of the stress-optic coefficients of thin single crystal silicon samples
Authors: He S. , Zheng T. , Danyluk S.
Published: September 2004

This paper summarizes the analysis of the influence of anisotropy on the stress-optic coefficients and the determination of the stress-optic tensor components π11−π12 and π44 using an infrared polariscope and calibration with four-point bending of thin silicon samples. Values obtained are π11−π12=9.88×10−13Pa−1 and π44=6.50×10−13Pa−1. A fringe multiplier was also introduced to increase the sensitivity of the infrared polariscope by up to seven times.
Unusual alloying behavior at the equilibrium immiscible Cu–Nb interfaces
Authors: Gong H. R. , Liu B. X.
Published: September 2004

Assisted by ab initio calculation, an n-body potential is derived for the equilibrium immiscible Cu–Nb system. Based on the potential, molecular dynamics simulations reveal that among the nine Cu∕Nb interfaces stacked by possible combinations of (100), (110), and (111) atomic planes, only the (111)Cu∕(110)Nb and (100)Cu∕(110)Nb interfaces could remain stable up to a temperature of 873K, and that introducing a disordered interlayer at these two interfaces could trigger solid-state amorphization, suggesting that the Cu∕Nb close-packed plane does not serve as a growth barrier, which was frequently the case observed previously in many other systems.
Reliability of a popular simulation code for predicting sputtering yields of solids and ranges of low-energy ions
Authors: Wittmaack Klaus
Published: September 2004

The SRIM simulation code, developed for calculating the stopping and range of ions in matter, was evaluated with the aim of determining its reliability for predicting sputtering yields of solids and ranges of low-energy ions. The simulations were performed using two recent versions, SRIM-2000 and -2003. Irrespective of the choice of the three input parameters of the code (the surface binding, the bulk binding, and the displacement energy), the sputtering yields at a fixed impact energy were found to exhibit an unusual Z1 dependence, which is strongly at variance with experimental results as well as with the predictions of analytical sputtering theory (Z1 and Z2 are the atomic numbers of projectile and target atoms, respectively). As shown in detail for targets of silicon and substantiated for titanium, the ratios of calculated to experimental or analytical yields are generally (much) too large for Z1∕Z2<0.7, decrease rapidly around Z1∕Z2=1, and are too small for Z1∕Z2>2 (high-to-low ratios differing by a factor of 3.4 at 1keV). Additional calculations of the projectile isotope effect in sputtering suggest that the sputtering-yield artifact of SRIM is buried in an incorrect approximation to projectile-target scattering. The low-energy electronic stopping powers of SRIM-2003 were found to be much too low. Differences between detailed and quick calculation modes were also identified. Additional problems are caused by the assumed nonrandom target-atom spacing. The use of SRIM in its present form for calculating sputtering yields and low-energy ranges cannot be recommended. As a by-product of this study it was found by analysis of published experimental data as well as by simulations that, at energies below about 5keV, the projected ranges of heavy ions in light element targets such as silicon increase with increasing projectile mass, a previously unknown effect.
Optimal lower bounds on the electric-field concentration in composite media
Authors: Lipton Robert
Published: September 2004

Composites made from two linear-isotropic-dielectric materials are considered. It is assumed that only the volume fraction and the two-point correlation function of each dielectric material are known. Lower bounds on all rth moments of the electric-field intensity inside each phase are obtained for r⩾2. A lower bound on the maximum field intensity inside the composite is also obtained. The bounds are given in terms of the one- and two-point statistics of the microgeometry. All of these bounds are shown to be the best possible as they are attained by the electric-field associated with a suitably constructed space-filling confocal-ellipsoid assemblage. The bounds provide a new opportunity for the assessment of local field behavior in terms of a statistical description of the microstructure.
Circumferentially magnetized and circumferentially polarized magnetostrictive/piezoelectric laminated rings
Authors: Dong Shuxiang , Li Jie-Fang , Viehland D.
Published: September 2004

Laminated composite rings of magnetostrictive Terfenol-D (TbxDy1−xFe2) and piezoelectric Pb(Zr1−xTix)O3 have been analyzed and prototyped. A circumferentially magnetized and circumferentially polarized (or C-C) magnetoelectric (ME) mode was investigated. Analysis and measurements have shown that C-C laminated rings have a high ME voltage coefficient under an applied vortex magnetic field.
Flexural strength of sapphire: Weibull statistical analysis of stressed area, surface coating, and polishing procedure effects
Authors: Klein Claude A.
Published: September 2004

The results of fracture testing are usually reported in terms of a measured strength, σM=σi¯±Δσi¯, where σi¯ is the average of the recorded peak stresses at failure, and Δσi¯ represents the standard deviation. This “strength” does not provide an objective measure of the intrisic strength since σM depends on the test method and the size of the volume or the surface subjected to tensile stresses. We first clarify issues relating to Weibull’s theory of brittle fracture and then make use of the theory to assess the results of equibiaxial flexure testing that was carried out on a variety of sapphire specimens, at three mechanical test facilities. Specifically, we describe the failure probability distribution in terms of a characteristic strength σC—i.e., the effective strength of a uniformly stressed 1cm2 area—which allows us to predict the average stress at failure of a uniformly loaded “window” if the Weibull modulus m is available. A Weibull statistical analysis of biaxial-flexure strength data thus amounts to obtaining the parameters σC and m, which is best done by directly fitting estimated cumulative failure probabilities to the appropriate expression derived from Weibull’s theory. We demonstrate that: (a) measurements performed on sapphire test specimens originating from two suppliers confirm the applicability of the area scaling law; for mechanically polished c- and r-plane sapphire, we obtain σC≃975MPa, m=3.40 and σC≃550MPa, m=4.10, respectively. (b) Strongly adhering compressive coatings can augment the characteristic strength by as much as 60%, in accord with predictions based on fracture-mechanics considerations, but degrade the Weibull modulus, which mitigates the benefit of this approach. And (c) Measurements performed at 600°C on chemomechanically polished c-plane test specimens indicate that proper procedures may enhance the characteristic strength by as much as 150%, with no apparent degradation of the Weibull modulus.
Elucidation by electron spin resonance and optical spectroscopy of the supersensitization mechanism in a red-sensitive AgCl-based photographic emulsion
Authors: Van Nylen Jan , Schoemaker Dirk , Goovaerts Etienne , Callant Paul , Viaene Kris , De Keyzer René
Published: September 2004

Electron spin resonance (ESR) and diffuse reflectance spectroscopy (DRS) were applied to study the origin of the strongly enhanced photographic sensitivity of red-sensitized (dye RS) AgCl systems upon addition of a Ultraviolet- (UV-) absorbing supersensitizer (SS). Both techniques were used to identify the radicals formed in this system upon spectral (red) as well as intrinsic (UV) excitation. Upon coadsorption of SS on the AgCl/RS system, the intensity of the photoinduced ESR signal is strongly increased. The ESR signals detected in systems with and without SS are very similar in line shape, line width, and g value, suggesting the formation of RS radicals. This was confirmed by the observation of a pair of absorption bands in the DRS spectrum, demonstrating that the radicals are formed on the RS molecules for all systems and ruling out supersensitization by hole trapping on the SS molecules for these systems. The effect of the supersensitizer is shown to be an overall increase in electron transfer efficiency from the dye molecules RS to the AgCl crystals. Indirect evidence is presented for the partitioning model, in which the electron transfer is facilitated by a rise of the lowest unoccupied molecular orbital level of the dye molecules, resulting from a reduction of the effective size of the RS aggregates.
Grain size dependence of magnetic properties in shock synthesized bulk Pr2Fe14B∕α-Fe nanocomposites
Authors: Jin Z. Q. , Thadhani N. N. , McGill M. , Li J. , Ding Y. , Wang Z. L. , Zeng H. , Chen M. , Cheng S. F. , Liu J. P.
Published: September 2004

The structural and magnetic properties of the melt-spun Pr2Fe14B∕α-Fe nanocomposite powders consolidated via shock-wave compression and subjected to postshock thermal treatment were investigated. Shock compression results in grain refinement, which leads to a reduction of an effective anisotropy and therefore an increase in the ferromagnetic exchange length, resulting in an enhanced exchange coupling in fully consolidated bulk magnets. A small amount of amorphous phase formed during the shock compression were observed to crystallize into Pr2Fe14B upon annealing above 600°C. The heat treatment also results in the recovery of coercivity partially lost during the consolidation, which can be related directly to the dependence of the effective anisotropy on the grain size, as illustrated by the transmission electron microscopy observation of grain refinement in the shock-consolidated bulk samples. A uniform grain morphology is suggested as a means for further increasing the magnetic properties of bulk nanocomposites.
Chromatic characterization of a three-channel colorimeter using back-propagation neural networks
Authors: Pardo P. J. , Pérez A. L. , Suero M. I.
Published: September 2004

This work describes a method for the chromatic characterization of a three-channel colorimeter of recent design and construction dedicated to color vision research. The colorimeter consists of two fixed monochromators and a third monochromator interchangeable with a cathode ray tube or any other external light source. Back-propagation neural networks were used for the chromatic characterization to establish the relationship between each monochromator’s input parameters and the tristimulus values of each chromatic stimulus generated. The results showed the effectiveness of this type of neural-network-based system for the chromatic characterization of the stimuli produced by any monochromator.
Mast cells: A unique source of renin
Authors: Silver Randi B. , Reid Alicia C. , Mackins Christina J. , Askwith Trevor , Schaefer Ulrich , Herzlinger Doris , Levi Roberto
Published: September 2004

In addition to the traditional renin–angiotensin system, a great deal of evidence favors the existence of numerous independent tissue-specific renin–angiotensin systems. We report that mast cells are an additional source of renin and constitute a unique extrarenal renin–angiotensin system. We use renin-specific antibodies to demonstrate that cardiac mast cells contain renin. Extending this observation to the human mast cell line HMC-1, we show that these mast cells also express renin. The HMC-1 renin RT-PCR product is 100% homologous to
Homo sapiens
renin. HMC-1 cells also contain renin protein, as demonstrated both by immunoblot and immunocytochemical analyses. Renin released from HMC-1 cells is active; furthermore, HMC-1 cells are able to synthesize renin. It is known that, in the heart, mast cells are found in the interstitium in close proximity to nerves and myocytes, which both express angiotensin II receptors. Inasmuch as myocardial interstitium contains angiotensinogen and angiotensin-converting enzyme, and because we were able to detect renin only in mast cells, we postulate that the release of renin from cardiac mast cells is the pivotal event triggering local formation of angiotensin II. Because of the ubiquity of mast cells, our results represent a unique paradigm for understanding local renin–angiotensin systems, not just in the heart, but in all tissues. Our findings provide a rationale for targeting mast cells in conjunction with renin–angiotensin system inhibitors in the management of angiotensin II-related dysfunctions.
Cross Talk between Sphingolipids and Glycerophospholipids in the Establishment of Plasma Membrane Asymmetry
Authors: Kihara Akio , Igarashi Yasuyuki
Published: September 2004

Glycerophospholipids and sphingolipids are distributed asymmetrically between the two leaflets of the lipid bilayer. Recent studies revealed that certain P-type ATPases and ATP-binding cassette (ABC) transporters are involved in the inward movement (flip) and outward movement (flop) of glycerophospholipids, respectively. In this study of phytosphingosine (PHS)-resistant yeast mutants, we isolated mutants for PDR5, an ABC transporter involved in drug efflux as well as in the flop of phosphatidylethanolamine. The pdr5 mutants exhibited an increase in the efflux of sphingoid long-chain bases (LCBs). Genetic analysis revealed that the PHS-resistant phenotypes exhibited by the pdr5 mutants were dependent on Rsb1p, a putative LCB-specific transporter/translocase. We found that the expression of Rsb1p was increased in the pdr5 mutants. We also demonstrated that expression of RSB1 is under the control of the transcriptional factor Pdr1p. Expression of Rsb1p also was enhanced in mutants for the genes involved in the flip of glycerophospholipids, including ROS3, DNF1, and DNF2. These results suggest that altered glycerophospholipid asymmetry induces the expression of Rsb1p. Conversely, overexpression of Rsb1p resulted in increased flip and decreased flop of fluorescence-labeled glycerophospholipids. Thus, there seems to be cross talk between sphingolipids and glycerophospholipids in maintaining the functional lipid asymmetry of the plasma membrane.
A Stepwise Surgical Technique Using the Medial Orbital Floor as the Key Landmark in Performing Endoscopic Sinus Surgery
Authors: Casiano Roy R.
Published: September 2004

Hypothesis The medial orbital floor (MOF) and adjacent bony ridge of the antrostomy, when combined with columellar measurements, are easily identifiable and consistent anatomic reference points from which critical orbital and skull base structures can be found during endoscopic sinus surgery.

Methods Two examiners, with varying endoscopic sinus surgery experience, performed endoscopic and direct measurements from the columnella and medial orbital floor to critical orbital and skull base structures on 11 human cadaver heads (18 sides). The distances to four critical skull base or orbital structures and to the anterior and posterior wall of the sphenoid sinus were measured. The mean, ranges, and standard deviations for all measurements (endoscopic and direct) were calculated and simple regression analysis was performed.

Results The mean and range of values for each of the variables correlated well between examiners, and between endoscopic and direct measurements. There was slightly more variability in measurements when the MOF was used. However, the differences were no more than a few millimeters and did not appear to affect the overall clinical use of these values.

Conclusions The MOF and adjacent bony ridge of the antrostomy, when combined with columellar measurements, are easily identifiable and consistent anatomic landmarks that are not affected by the presence of significant inflammatory disease or previous surgery. These reference points provide even the most inexperienced surgeon with precise anatomic localization within the paranasal sinuses. They also determine the correct anteroposterior trajectory into the sphenoid sinus, whereby inadvertent intracranial or intraorbital complications may be avoided.
Photofrin‐Mediated Photodynamic Therapy for Treatment of Aggressive Head and Neck Nonmelanomatous Skin Tumors in Elderly Patients
Authors: Schweitzer Vanessa Gayl
Published: September 2004

Objectives/Hypothesis Aggressive nonmelanomatous skin tumors (basal cell carcinoma, squamous cell carcinoma, and Bowen's disease) of the head and neck often occur in Caucasian elderly patients because of prior history of radiation therapy for teenage acne and adenoid hypertrophy; severe solar‐induced skin damage, basal cell nevus syndrome, and other genetic skin diseases; chemical carcinogen exposure; and drug‐induced immunosuppression. In patients with large, multifocal recurrent tumors, standard therapy with acceptable cosmetic outcomes may be difficult. Photodynamic therapy (PDT) with photosensitizing agents selectively taken up by skin provides a primary or adjunct intraoperative option for treatment of this special group of cancer patients.

Study Design Retrospective review.

Methods Patients (age range, 60–92 y) were injected with 1.0 mg/kg PHOTOFRIN (dihematoporphyrin derivative) followed 60 hours later by intraoperative laser light activation. Light was delivered through microlens fiber by means of an argon dye laser at 630 nm at a light dose of 100 to 300 J/cm2 microlens delivery for PDT alone and 50 to 100 J/cm2 microlens delivery for tumor bed resection sites in the case of adjunct PDT combined with surgical resection.

Results Twelve cases of aggressive recurrent nonmelanomatous cutaneous tumors of the head and neck were treated. Five patients received intraoperative PDT combined with surgical resection, including radical mastoidectomy, lateral temporal bone resection, partial maxillectomy with temporalis myofacial flap reconstruction, and wide local resection with secondary intention healing of exposed scalp wounds. Seven patients were treated with PDT alone for extensive multiple cutaneous lesions or wide‐field primary or recurrent nonmelanomatous tumors. Ten patients achieved complete responses (follow‐up, 6–60 mo) with excellent wound healing and cosmetic outcomes.

Conclusions PHOTOFRIN‐mediated PDT is an excellent locoregional oncological modality for aggressive primary or recurrent basal cell carcinoma and squamous cell carcinoma, particularly in elderly patients who were previously treated with extensive Mohs microsurgery, surgical resection, and external‐beam radiation therapy. Multiple repeat treatments are well tolerated, painless, without systemic morbidity, and amenable to local anesthesia or intravenous sedation for PDT alone, and wound healing and cosmetic outcomes are excellent.
Breast‐conserving therapy in young women with invasive carcinoma of the breast
Authors: Borg MF
Published: September 2004

Higher local recurrence rates have been reported in young women with invasive carcinoma of the breast treated with breast‐conserving therapy (BCT). However, age itself may not be responsible for this increased risk of recurrence. To investigate this further, a computerized literature search of MEDLINE was performed using data from 1996 to May 2003. The research was limited to female patients with localized, invasive adenocarcinoma of the breast but also included patients of young age with ductal carcinoma in situ. Women of young age with breast cancer, treated with BCT are at an increased risk of recurrence ranging from 7.5 to 35%. However, the data would suggest that the increased risk is secondary to the association of young age with more aggressive tumours and a positive family history of breast cancer. Other factors that may explain the adverse prognosis in women of a young age include associated genetic abnormalities and the lack of mammographic screening programmes for women of young age. Young age is a risk factor for breast recurrence after BCT. However, management decisions should be based on tumour stage, grade and other related prognostic features rather than on young age alone.
Effects of Social Interaction between Afghan Refugees and Iranians on Reproductive Health Attitudes
Authors: Piran Parviz
Published: September 2004

Afghan refugees in Iran, like many Muslims around the world, think that using contraceptives is against their religious beliefs. The majority of Iranians also thought so until a decade ago. Since then an all‐encompassing social movement has emerged in Iran in which women and young people have played decisive roles. This movement has led to an attitude shift towards acceptance of family planning across Iranian society. High‐ranking clerics, responding to the social movement, issued progressive edicts indicating that poor families could practise family planning. This paper reports the findings of focus group studies carried out among Afghan refugee men in two communities in Iran. The findings indicate that exposure to Iranian life, especially the rulings of Iranian clerics, have influenced Afghans' views on family planning. The findings also indicate that a system of justification is needed to help people avoid both social sanctions and individual stresses resulting from a controversial practice regarded as a sin for centuries.
Newly secreted adenylate cyclase toxin is responsible for intoxication of target cells by Bordetella pertussis
Authors: Gray M. C. , Donato G. M. , Jones F. R. , Kim T. , Hewlett E. L.
Published: September 2004

Adenylate cyclase (AC) toxin is present on the surface of Bordetella pertussis organisms and their addition to eukaryotic cells results in increases in intracellular cAMP. To test the hypothesis that surface‐bound toxin is the source for intoxication of cells when incubated with B. pertussis, we characterized the requirements of intoxication from intact bacteria and found that this process is calcium‐dependent and blocked by monoclonal antibody to AC toxin or antibody against CD11b, a surface glycoprotein receptor for the toxin. Increases in intracellular cAMP correlate with the number of adherent bacteria, not the total number present in the medium, suggesting that interaction of bacteria with target cells is important for efficient delivery of AC toxin. A filamentous haemagglutinin‐deficient mutant (BP353) and a clinical isolate (GMT1), both of which have a marked reduction in AC toxin on their surface, and wild‐type B. pertussis (BP338) from which surface AC toxin has been removed by trypsin, were fully competent for intoxicating target cells, demonstrating that surface‐bound AC toxin is not responsible for intoxication. B. pertussis killed by gentamicin or gamma irradiation were unable to intoxicate, illustrating that toxin delivery requires viable bacteria. Furthermore, CCCP, a protonophore that disrupts the proton gradient necessary for the secretion of related RTX toxins, blocked intoxication by whole bacteria. These data establish that delivery of this toxin by intact B. pertussis is not dependent on the surface‐associated AC toxin, but requires close association of live bacteria with target cells and the active secretion of AC toxin.
Lack of mismatch correction facilitates genome evolution in mycobacteria
Authors: Springer Burkhard , Sander Peter , Sedlacek Ludwig , Hardt Wolf‐Dietrich , Mizrahi Valerie , Schär Primo , Böttger Erik C.
Published: September 2004

In silico genome sequence analyses suggested that mycobacteria are devoid of the highly conserved mutLS‐based post‐replicative mismatch repair system. Here, we present the first biological evidence for the lack of a classical mismatch repair function in mycobacteria. We found that frameshifts, but not general mutation rates are unusually high in Mycobacterium smegmatis. However, despite the absence of mismatch correction, M. smegmatis establishes a strong barrier to recombination between homeologous DNA sequences. We show that 10–12% of DNA sequence heterology restricts initiation of recombination but not extension of heteroduplex DNA intermediates. Together, the lack of mismatch correction and a high stringency of initiation of homologous recombination provide an adequate strategy for mycobacterial genome evolution, which occurs by gene duplication and divergent evolution.
Testing the branch autonomy theory: a 13C/14C double‐labelling experiment on differentially shaded branches
Authors: LACOINTE A. , DELEENS E. , AMEGLIO T. , SAINT‐JOANIS B. , LELARGE C. , VANDAME M. , SONG G. C. , DAUDET F. A.
Published: September 2004

The impact of a heterogeneous within‐crown light environment on carbon allocation was investigated on young walnut trees trained on two branches: one left in full sunlight, the other shaded until leaf fall resulting in 67% reduction in photosynthetically active radiation. In September, the two branches were separately labelled with 14CO2 and 13CO2, respectively, so that the photosynthates from each branch could be traced independently at the same time. Although some carbon movements could be detected within 5 d in both directions (including from the shaded branch to the sun branch), between‐branch carbon movements were very limited: approximately 1% of the diurnal net assimilation of a branch. At this time of the year branch autonomy was nearly total, leading to increased relative respiratory losses and a moderate growth deficit in the shaded branch. The ratio of growth to reserve storage rate was only slightly affected, indicating that reserves acted not as a mere buffer for excess C but as an active sink for assimilates. In winter, branch autonomy was more questionable, as significant amounts of carbon were imported into both branches, possibly representing up to 10% of total branch reserves. Further within‐plant carbon transfers occurred in spring, which totally abolished plant autonomy, as new shoots sprouted on each branch received significantly more C mobilized from tree‐wide reserves than from local, mother‐branch located reserves. This allowed great flexibility of tree response to environment changes at the yearly time scale. As phloem is considered not functional in winter, it is suggested that xylem is involved as the pathway for carbohydrate movements at this time of the year. This is in agreement with other results regarding sugar exchanges between the xylem vessels and the neighbouring reserve parenchyma tissues.
Information Transfer in Multienzyme Complexes
Authors: Avilan Luisana , Gontero Brigitte , Lebreton Sandrine , Ricard Jacques
Published: September 2004

A mutant phosphoribulokinase has been isolated from the 12‐2B mutant of Chlamydomonas reinhardtii. In this mutant, Arg64 has been replaced by Cys. The enzyme, which may exist in the dimeric and tetrameric states, is almost devoid of activity. Neither of these enzymes is able to form a complex with glyceraldehyde‐3‐phosphate dehydrogenase.

The phosphoribulokinase gene has been expressed in Escherichia coli. The resulting recombinant protein, after isolation and purification, is apparently identical to the native enzyme extracted from the chloroplast. Three mutants have been generated by site directed mutagenesis. Arg64 has been replaced by Ala, Lys or Glu. With the exception of the latter, the two other mutants, [A64]phosphoribulokinase and [K64]phosphoribulokinase, are active when they are reduced, and nearly totally inactive in their oxidized state. Their activity, however, is decreased relative to that of the native, or to that of the wild‐type recombinant phosphoribulokinase. Both the catalytic constant and the apparent affinity of ribulose 5‐phosphate are decreased relative to the corresponding values obtained for the wild‐type, the native or the recombinant enzyme.

Whereas the [A64]phosphoribulokinase is unable to form a complex with glyceraldehyde‐3‐phosphate dehydrogenase, [K64]phosphoribulokinase does, but the stability of the resulting complex is much decreased relative to that of the wild‐type complex. The oxidized mutant [K64]phosphoribulokinase becomes active in the presence of glyceraldehyde‐3‐phosphate dehydrogenase but this activity is smaller than that of the corresponding wild‐type enzyme.

Taken together, these results show that Arg64 plays a major role in the association of the two enzymes and in the information transfer that takes place between glyceraldehyde‐3‐phosphate dehydrogenase and phosphoribulokinase. As this residue also appears to be important for catalytic activity, it may be tempting to consider that it stabilizes a conformation that is required for both the catalytic activity and the formation of the bienzyme complex.
Regulation of Salt Tolerance in Fission Yeast by a Protein‐Phosphatase‐Z‐Like Ser/Thr Protein Phosphatase
Authors: Balcells Llufs , Gómez Néstor , Casamayor Antonio , Clotet Josep , Ariño Joaquin
Published: September 2004

In the yeast Saccharomyces cerevisiae, Na+ efflux is mediated by the Ena1 ATPase, and the expression of the ENA1 gene is regulated by the Ppz1 and Ppz2 Ser/Thr protein phosphatases. On the contrary, in the fission yeast Schizosaccharomyces pombe, effective output of Na+ is attributed to the H+/Na+ antiporter encoded by the sod2 gene. We have isolated a S. pombe gene (pzh1) that encodes a 515‐amino‐acid protein that is 78% identical, from residue 193 to the COOH terminus, to the PPZ1 and PPZ2 gene products. Bacterially expressed Pzh1p shows enzymatic characteristics virtually identical to those of recombinant Ppz1p. When expressed in high‐copy number from the PPZ1 promoter, the pzh1 ORF rescues the caffeine‐induced lytic defect and slightly decreases the high salt tolerance of S. cerevisiae ppz1Δ mutants. Disruption of pzh1 yields viable S. pombe cells and has virtually no effect on tolerance to caffeine or osmotic stress, but it renders the cells highly tolerant to Na+ and Li+, and hypersensitive to K+. Although lack of pzh1 results in a 2–3‐fold increase in sod2 mRNA, the pzh1 mutation significantly increases salt tolerance in the absence of the sod2 gene, suggesting that the phosphatase also regulates a Sod2‐independent mechanism. Therefore, the finding of a PPZ‐like protein phosphatase involved in the regulation of salt tolerance in fission yeast reveals unexpected aspects of cation homeostasis in this organism.
Inefficient Repair of RNA · DNA Hybrids
Authors: Kamath‐Loeb Ashwini S. , Hizi Amnon , Tabone John , Solomon Marjorie S. , Loeb Lawrence A.
Published: September 2004

RNA · DNA hybrids are commonly observed during normal biological processes. We tested the ability of three DNA‐repair enzymes to remove lesions from the DNA strand of RNA · DNA heteroduplexes. Three nucleotide analogs, 5‐hydroxy‐2·‐deoxycytidine triphosphate, 8‐oxo‐2·‐deoxyguanosine triphosphate, and O6‐methyl‐2·‐deoxyguanosine triphosphate, representative of lesions generated by oxygen damage and methylating agents, were incorporated into the DNA strand synthesized using either a DNA or RNA template. The extended DNA · DNA and RNA · DNA hybrids were used as substrates for bacterial formamidopyrimidine‐DNA glycosylase, Nth protein (endonuclease III) and O6‐methylguanine‐DNA methyltransferase. We show that all three lesions are readily cleaved from the DNA strand of a DNA · DNA duplex but are relatively resistant to cleavage when present in the DNA strand of an RNA · DNA hybrid. Our in vitro studies suggest that damaged DNA in RNA · DNA hybrids is less likely to be repaired in vivo.
Configurations of Diastereomeric Hydroxyethylene Isosteres Strongly Affect Biological Activities of a Series of Specific Inhibitors of Human‐Immunodeficiency‐Virus Proteinase
Authors: Konvalinka Jan , Litera Jaroslav , Weber Jan , Vondrášek Jiří , Hradílek Martin , Souček Milan , Pichová Iva , Majer Pavel , Štrop Petr , Sedlácek Juraj , Heuser Anke‐Mareil , Kottler Hubert , Kräusslich Hans‐Georg
Published: September 2004

Human immunodeficiency virus (HIV) proteinase (PR) represents an important target for antiviral chemotherapy. We present an analysis of inhibitory activities of a series of pseudopeptide inhibitors of HIV‐1 PR. All inhibitors were N‐protected tetrapeptides with the scissile bond replaced by a non‐hydrolysable hydroxyethylene or hydroxyethylamine isostere. To elucidate subtle structural requirements of the PR binding cleft, we synthesised inhibitors with four combinations of configurations at the asymmetric carbons of the isostere. Compounds were tested in vitro using purified recombinant enzyme and a chromogenic peptide substrate. The differences in inhibition constants between individual diastereoisomers reached three orders of magnitude. The most active hydroxyethylene‐containing inhibitor possessed the 2R, 4S, 5S configuration at the isostere. Inhibitor activity was also tested in mammalian cell culture by analysing reduction of viral polyprotein processing and virus infectivity. The results obtained in tissue culture were generally in agreement with the in vitro data, giving a similar order of potency for the individual diastereoisomers. The most active compounds completely blocked production of infectious virus. A simulation method for interaction was employed to build a model of the inhibitors in the PR active site, to identify the interactions responsible for the differences in activities of individual stereo‐isomers, and to estimate the relative contribution of individual structural features to the overall inhibitory activity.
The Contribution of Water to the Selectivity of Pyruvate Kinase for Na+ and K+
Authors: Ramírez‐Silva Leticia , Oria Jesús , Gómez‐Puyou Armando , De Gómez‐Puyou Marietta Tuena
Published: September 2004

For many years it has been known that K+ is an essential activator of pyruvate kinase [Kachmar, J. F. & Boyer, P. D. (1953) J. Biol. Chem. 200, 669–683] and that Na+ induces relatively small enhancements of activity. The effect of these two alkali metal ions on the activity of pyruvate kinase entrapped in the low water environment of reverse micelles formed with cetyltrimethylammonium, hexanol, n‐octane and various water concentrations was studied. In reverse micelles with 3.6% water, the activity with 7 mM Na+ is more than 82 times higher than in aqueous solution with an equivalent Na+ concentration. As the concentration of water in reverse micelles is raised, the activating effect of relatively low concentrations of Na+ (or K+) decreases simultaneously to a more than 100‐fold increase in the concentration of Na+ or K+ required for attaining half‐maximal activation. Similar results were obtained with NH4+, Rb+ and Cs+. Therefore, the amount of water in the system is critical for observing activation by alkali metal ions. In fact, the concentration of Na+ required for half‐maximal activation in standard aqueous media is higher than the concentrations that can be experimentally assayed. As evidenced from fluorescence and kinetic data, it appears that the entrapment of pyruvate kinase in reverse micelles does not produce gross structural alterations. Therefore, it is suggested that in conventional aqueous systems, the basis of the high discrimination between Na+ and K+ by pyruvate kinase is the higher energy required for desolvating Na+. Nevertheless, at all the water concentrations studied, the activities reached with K+ were higher than with Na+ which suggests that the Na+ form of the enzyme has a lower catalytic capacity than the K+‐enzyme complex.
Tumour Incidence, Prevalence and Lethality Estimation in the Absence of Cause-of-Death Information
Authors: Härkänen T. , Arjas E.
Published: September 2004

A Bayesian intensity model is presented for studying a bioassay problem involving interval-censored tumour onset times, and without discretization of times of death. Both tumour lethality and base-line hazard rates are estimated in the absence of cause-of-death information. Markov chain Monte Carlo methods are used in the numerical estimation, and sophisticated group updating algorithms are applied to achieve reasonable convergence properties. This method was tried on the rat tumorigenicity data that have previously been analysed by Ahn, Moon and Kodell, and our results seem to be more realistic.
In vivo somatic delivery of plasmid DNA and retrograde transport to obtain cell‐specific gene expression in the central nervous system
Authors: Morris Renée , Morgan Branwen S. , Lewis Trevor M. , Pierce Kerrie D. , Pisano Anthony , Schofield Peter R.
Published: September 2004

We utilised the retrograde transport machinery of neurones to deliver naked plasmid DNA into the central nervous system. A 5.4‐kb fragment of the glycine receptor (GlyR) α1 subunit gene was cloned and used to drive the expression of a construct encoding for the enhanced green fluorescent protein (EGFP). Injections of the plasmid DNA in the tongue of mice resulted in the expression of the marker protein in hypoglossal motor neurones, showing that the GlyRα1 promoter sequence is sufficient to drive expression of the transgene. In order to determine the specificity of expression of the 5.4‐kb fragment of the GlyR α1 subunit gene promoter, we subsequently injected the plasmid DNA into the mouse central nucleus of the amygdala. This nucleus receives projections from the parabrachial nucleus, a brainstem area that has a high density of GlyRs, and from the insular cortex, a forebrain structure devoid of GlyRs. We observed EGFP‐labelled neurones in the parabrachial nucleus, but not in the insular cortex, indicating that the 5.4‐kb GlyR α1 subunit gene promoter confers specificity of expression. This approach provides a simple and rapid way to identify, in vivo, promoter elements that mediate neurone‐specific gene expression.
Fabrication of a Maxillofacial Prosthesis Using a Computer‐Aided Design and Manufacturing System
Authors: Tsuji Mitsuhiro , Noguchi Nobuhiro , Ihara Koichiro , Yamashita Yoshio , Shikimori Michio , Goto Masaaki
Published: September 2004

Purpose: Maxillofacial prostheses are usually fabricated on the basis of impressions made with dental‐impression material. The extent to which the prosthesis reproduces normal facial morphology depends on the clinical judgment of the individual fabricating the prosthesis. This paper describes a computer‐aided design and manufacturing (CAD/CAM) system for the fabrication of maxillofacial prostheses. This system will provide a more consistently accurate reproduction of facial morphology.

Materials and Methods: Facial measurements were taken using a non‐contact three‐dimensional laser morphological measurement system. The measurements were sent to a computer numerical controlled (CNC) milling machine to generate a cast of the patient's face for the fabrication of prosthesis.

Results: Facial contours were measured using a laser. This method minimizes patient discomfort and avoids soft tissue distortion by impression material. Moreover, the digital data obtained is easy to store and transmit, and mirror‐images can be readily generated by computer processing.

Conclusion: This method offers an objective, quantified approach for fabricating maxillofacial prostheses.
Simple(r) Soft Tissue Masque for Individual Fixed Restorations
Authors: Tan Philip Leong Biow , Ruder Gary Alan
Published: September 2004

This article describes a simplified technique for creating a soft tissue masque to aid in shaping the gingival contours of fixed restorations. The additional clinical visit that has been previously described is circumvented, and only one master cast is required.
Polymorphism in Presolar Al
2
O
3
Grains from Asymptotic Giant Branch Stars
Authors: Stroud Rhonda M. , Nittler Larry R. , Alexander Conel M. O'D.
Published: September 2004

We report microstructural and isotopic analyses of two presolar Al
2
O
3
grains. Aluminum oxide is important cosmically, because its presence has been detected in the infrared spectra of the circumstellar envelopes of O-rich asymptotic giant branch stars and because it is predicted to be the first solid to condense in these stellar environments. The two grain structures, one corundum and the other amorphous, confirm that asymptotic giant branch stars produce both phases. The variation in structure and Ti content demonstrates that Al
2
O
3
can condense in the absence of TiO
2
seed clusters but that Ti may be important in determining the crystal structure.