bluuebunny/crossref_metadata_2025 huggingface dataset:
Mutational activation of the MAP3K8 protooncogene in lung cancer
Authors: Clark Adam Michael , Reynolds Steven H. , Anderson Marshall , Wiest Jonathan S.
Published: July 2004

The MAP3K8 protooncogene (Cot/Tpl‐2) activates the MAP kinase, SAP kinase, and NF‐κB signaling pathways. MAP3K8 mutations occur in the rat homologue, but activating mutations have yet to be identified in primary human tumors. We have identified MAP3K8 as a transforming gene from a human lung adenocarcinoma and characterized a 3′ end mutation in the cDNA. In addition, we confirmed that the mutation occurs in the original lung tumor, and we screened a series of lung cancer cell lines to determine whether the MAP3K8 mutation is a common occurrence in lung tumorigenesis. The oncogene was isolated and identified with the NIH3T3 nude mouse tumorigenicity assay and cDNA library screening. The gene was analyzed by polymerase chain reaction (PCR), single‐strand conformational polymorphism (SSCP), and 3′RACE for mutations. The mutation was localized to MAP3K8 exon 8 and confirmed in the primary tumor DNA. Both wild‐type and mutant MAP3K8 cDNAs transformed NIH3T3 cells, but the transforming activity of the mutant was much greater than that of the wild type. PCR‐SSCP screening of cell line cDNAs identified one silent polymorphism in cell line SK‐LU‐1. Although we were unable to find additional activating mutations, these data support a role for MAP3K8 activity in cellular transformation, but suggest that mutational activation of the gene is a rare event in lung cancer. © 2004 Wiley‐Liss, Inc.
Analysis of somatic APC mutations in rare extracolonic tumors of patients with familial adenomatous polyposis coli
Authors: Bläker Hendrik , Sutter Christian , Kadmon Martina , Otto Herwart F. , von Knebel‐Doeberitz Magnus , Gebert Johannes , Helmke Burkhard M.
Published: July 2004

Patients with familial adenomatous polyposis coli (FAP) carry heterozygous mutations of the APC gene. At a young age, these patients develop multiple colorectal adenomas that consistently display a second somatic mutation in the remaining APC wild‐type allele. Inactivation of APC leads to impaired degradation of β‐catenin, thereby promoting continuous cell‐cycle progression. The role of APC inactivation in rare extracolonic tumors of FAP patients has not been characterized sufficiently. Among tissue specimen from 174 patients with known APC germ‐line mutations, we identified 8 tumors infrequently seen in FAP. To investigate the pathogenic role of APC pathway deregulation in these lesions, they were analyzed for second‐hit somatic mutations in the mutational cluster region of the APC gene. Immunohistochemistry was performed to compare the expression pattern of β‐catenin to the mutational status of the APC gene. Exon 3 of the β‐catenin gene (CTNNB1) was analyzed for activating mutations to investigate alternative mechanisms of elevated β‐catenin concentration. Although CTNNB1 mutations were not observed, second somatic APC mutations were found in 4 of the 8 tumors: a uterine adenocarcinoma, a hepatocellular adenoma, an adrenocortical adenoma, and an epidermal cyst. These tumors showed an elevated concentration of β‐catenin. No APC mutations were seen in focal nodular hyperplasia of the liver, angiofibrolipoma, and seborrheic wart. This is the first study reporting second somatic APC mutations in FAP‐associated uterine adenocarcinoma and epidermal cysts. Furthermore, our data strengthen a role for impaired APC function in the pathogenesis of adrenal and hepatic neoplasms in FAP patients. © 2004 Wiley‐Liss, Inc.
Divergent patterns of telomere maintenance mechanisms among human sarcomas: Sharply contrasting prevalence of the alternative lengthening of telomeres mechanism in Ewing's sarcomas and osteosarcomas
Authors: Ulaner Gary A. , Hoffman Andrew R. , Otero Jesse , Huang Hsuan‐Ying , Zhao Zhiquan , Mazumdar Madhu , Gorlick Richard , Meyers Paul , Healey John H. , Ladanyi Marc
Published: July 2004

Two types of telomere maintenance mechanisms (TMMs) have been described in human tumors: telomerase activation and alternative lengthening of telomeres (ALT). Although the vast majority of epithelial tumors rely on telomerase activation, many mesenchymal tumors rely on ALT for telomere maintenance, but within this tumor group, the TMMs used by translocation‐associated sarcomas have not been systematically studied. We studied telomere lengths and telomerase expression and activity in 30 uncultured tumor samples and in 10 cell lines of Ewing's sarcoma, a prototypical translocation‐associated sarcoma, and compared the data to an identical analysis of 60 osteosarcomas, the most common type of sarcoma lacking a specific translocation. Telomerase activity was demonstrated in 21 Ewing's sarcoma tumor samples (70%) and in 9 of 10 Ewing's sarcoma cell lines. Evidence of ALT, indicated by the presence of long and heterogeneous telomeres, was observed only in the cell line without telomerase activity and in none of the 30 Ewing's sarcoma tumor samples. The 9 Ewing's sarcoma patients whose tumors lacked detectable telomerase activity did not differ significantly from the remaining patients in age, stage, EWSR1–FLI1 fusion type, prevalence of TP53 point mutations, or overall survival. The low prevalence of ALT in Ewing's sarcoma contrasted sharply with our data on TMMs in 60 osteosarcomas, which showed ALT in 38 of 60 cases (P < 0.0001). The present study, together with emerging published data on other sarcoma types, suggests that a predominance of telomerase activation in the absence of ALT may characterize sarcomas with specific chromosomal translocations (such as Ewing's sarcoma), whereas a high prevalence of ALT appears typical of sarcomas with nonspecific complex karyotypes (such as osteosarcoma). © 2004 Wiley‐Liss, Inc.
Alternative mechanisms of gene amplification in human cancers
Authors: Kuwahara Yoshitaka , Tanabe Chikako , Ikeuchi Tatsuro , Aoyagi Kazuhiko , Nishigaki Michiko , Sakamoto Hiromi , Hoshinaga Kiyotaka , Yoshida Teruhiko , Sasaki Hiroki , Terada Masaaki
Published: July 2004

Gene amplification is a common phenomenon in cancer. Cytogenetic analyses have indicated that breakage‐fusion‐bridge (BFB) cycles drive intrachromosomal amplification of some oncogenes in a head‐to‐head manner in human cancers. However, the complex structures of an amplified sequence found in cancers are not always explained by the BFB model. At the 17q21 locus, which is not linked to common fragile sites, we discovered a recombination hot spot harboring amplicon repeats in tandem in a head‐to‐tail orientation, with the interamplicon junctions in each cancer cell being homogeneous. These findings clearly show the presence of alternative mechanisms other than BFB cycles in oncogene amplification. © 2004 Wiley‐Liss, Inc.
Recursive constructions for optimal (n,4,2)‐OOCs
Authors: Chu Wensong , Colbourn Charles J.
Published: July 2004

In [3], a general recursive construction for optical orthogonal codes is presented, that guarantees to approach the optimum asymptotically if the original families are asymptotically optimal. A challenging problem on OOCs is to obtain optimal OOCs, in particular with λ > 1. Recently we developed an algorithmic scheme based on the maximal clique problem (MCP) to search for optimal (n, 4, 2)‐OOCs for orders up to n = 44. In this paper, we concentrate on recursive constructions for optimal (n, 4, 2)‐OOCs. While “most” of the codewords can be constructed by general recursive techniques, there remains a gap in general between this and the optimal OOC. In some cases, this gap can be closed, giving recursive constructions for optimal (n, 4, 2)‐OOCs. This is predicated on reducing a series of recursive constructions for optimal (n, 4, 2)‐OOCs to a single, finite maximal clique problem. By solving these finite MCP problems, we can extend the general recursive construction for OOCs in [3] to obtain new recursive constructions that give an optimal (n · 2x, 4, 2)‐OOC with x ≥ 3, if there exists a CSQS(n). © 2004 Wiley Periodicals, Inc.
A construction of resolvable nested 3‐designs
Authors: Rai Shivani , Banerjee Shakti , Kageyama Sanpei
Published: July 2004

A method of constructing resolvable nested 3‐designs from an affine resolvable 3‐design is proposed with one example. © 2004 Wiley Periodicals, Inc.
Production of β‐galactosidase from recombinant Saccharomyces cerevisiae grown on lactose
Authors: Domingues Lucília , Oliveira Carla , Castro Inês , Lima Nelson , Teixeira José A
Published: July 2004

Improved productivity and costs reduction in fermentation processes may be attained by using flocculating cell cultures. The production of extracellular heterologous β‐galactosidase by recombinant flocculating Saccharomyces cerevisiae cells, expressing the lacA gene (coding for β‐galactosidase) of Aspergillus niger under the ADHI promotor and terminator in a bioreactor was studied. The effects of lactose concentration and yeast extract concentration on β‐galactosidase production in a semi‐synthetic medium were analysed. The extracellular β‐galactosidase activity increased linearly with increasing initial lactose concentrations (5–150 g dm−3). β‐Galactosidase production also increased with increased yeast extract concentration. During the entire fermentation, no accumulation of the hydrolysed sugars, glucose and galactose, was observed. The catabolic repression of the recombinant strain when cultured in a medium containing equal amounts of glucose and galactose was confirmed. In complete anaerobiosis, the fermentation of lactose resulted in a very slow fermentation pattern with lower levels of β‐galactosidase activity. The bioreactor operation together with optimisation of culture conditions (lactose and yeast extract concentration) led to a 21‐fold increase in the extracellular β‐galactosidase activity produced when compared with preliminary Erlenmeyer fermentations. Copyright © 2004 Society of Chemical Industry
Chloride‐promoted leaching of chalcopyrite concentrate by biologically‐produced ferric sulfate
Authors: Kinnunen Päivi H‐M , Puhakka Jaakko A
Published: July 2004

The effects of chloride ions on chalcopyrite leaching by biologically‐produced ferric sulfate solution and on the iron‐oxidizing culture were determined. Chloride ions significantly increased chalcopyrite leaching by ferric sulfate at 67 °C and 87 °C, but slowed down the leaching at 50 °C. At 90 °C, chloride at 5 g dm−3 (0.25 g Cl− g−1 concentrate) increased the copper yield from 60 to 100% in approximately 2 weeks. Further increase in Cl− concentration did not affect the leaching. Addition of chloride increased both leaching yields and iron precipitation, which shows that the passivation was not due to iron precipitation. A decreased Ag‐potential of 60 mV against an Ag/AgCl reference electrode in the presence of Cl− indicates the accumulation of partially oxidized forms of dissolved sulfur compounds such as thiosulfate and polythionate instead of elemental sulfur and, thus, a decrease in sulfur passivation. A chloride concentration of 5 g dm−3 did not affect the iron oxidation rate of the iron‐oxidizing culture dominated by Leptospirillum ferriphilum. Copyright © 2004 Society of Chemical Industry
Optimization of the production of chitosan from beet molasses by response surface methodology
Authors: Göksungur Y
Published: July 2004

Chitosan was produced by Rhizopus oryzae 00.4367 in shake flask culture and a stirred tank fermenter. Synthetic medium, treated and untreated beet molasses were used as cultivation media in shake flask cultures. In the stirred tank fermenter, the cultivation media were synthetic medium and untreated beet molasses. Shake flask culture containing untreated molasses with a sugar concentration of 40 g dm−3 produced the maximum chitosan yield (961 mg dm−3). Chitosan concentration reached its maximum value at the late exponential growth phase of R oryzae. In all experiments almost 8–10% of biomass and 32–38% of alkali‐insoluble material was extracted as chitosan. A central composite design was employed to determine the optimum values of process variables (aeration rate, agitation speed and initial sugar concentration) leading to maximum chitosan concentration in the stirred tank fermenter. In all cases, the fit of the model was found to be good. Aeration rate, agitation speed and initial sugar concentration had a strong linear effect on chitosan concentration. Moreover, the concentration of chitosan was significantly influenced by the negative quadratic effects of the given variables and by their positive or negative interactions. A maximum chitosan concentration of 1109.32 mg dm−3 was obtained in untreated molasses medium containing an initial sugar concentration of 45.37 g dm−3 with an aeration rate and agitation speed of 2.10 vvm and 338.93 rpm, respectively. Copyright © 2004 Society of Chemical Industry
Chemical treatment of cork‐processing wastewaters for potential reuse
Authors: Acero Juan L , Benitez F Javier , Heredia Jesus Beltran de , Leal Ana I
Published: July 2004

The chemical treatment of cork‐processing wastewater by ozonation, alone and in combination with hydrogen peroxide and UV radiation was investigated. A reduction of the chemical oxygen demand (COD) ranging from 42% to 76% was obtained during ozonation after 3 h of reaction, depending on the experimental conditions. The additional presence of hydrogen peroxide and UV radiation enhanced the efficiency of the ozonation treatment due to the contribution of the OH radicals formed in the decomposition of ozone. Thus, final reductions of the COD higher than 90% and a complete elimination of phenolic compounds and absorbance at 254 nm were achieved in both Advanced Oxidation Processes (AOPs), O3/H2O2 and O3/UV. Therefore the effluent resulting from the ozonation treatments can be reused in the cork‐processing industry. In a second step, the chemical treatment was conducted by means of UV radiation alone and by the action of hydroxyl radicals, which were generated by the following AOPs: UV/H2O2, Fenton's reagent, and photo‐Fenton system. The single photochemical process resulted in 9% of the organic matter present being removed, while the AOPs significantly enhanced this reduction with values in the range 20–75%. Kinetic studies for both groups of treatments were performed, and apparent kinetic rate constants were evaluated. In the ozone‐based experiments, the rate constants ranged from 1846 to 10922 dm3 mol−1 O3 h−1, depending on the operating conditions. In the oxidation experiments using oxidants other than ozone, the rate constants varied between 0.06 and 1.19 h−1. Copyright © 2004 Society of Chemical Industry
Wet oxidation pre‐treatment of woody yard waste: parameter optimization and enzymatic digestibility for ethanol production
Authors: Lissens Geert , Klinke Helene , Verstraete Willy , Ahring Birgitte , Thomsen Anne Belinda
Published: July 2004

Woody yard waste with high lignin content (22% of dry matter (DM)) was subjected to wet oxidation pre‐treatment for subsequent enzymatic conversion and fermentation. The effects of temperature (185–200 °C), oxygen pressure (3–12 bar) and addition of sodium carbonate (0–3.3 g per 100 g DM biomass) on enzymatic cellulose and hemicellulose (xylan) convertibility were studied. The enzymatic cellulose conversion was highest after wet oxidation for 15 min at 185 °C with addition of 12 bars of oxygen and 3.3 g Na2CO3 per 100 g waste. At 25 FPU (filter paper unit) cellulase g−1 DM added, 58–67% and 80–83% of the cellulose and hemicellulose contained in the waste were converted into monomeric sugars. The cellulose conversion efficiency during a simultaneous saccharification and fermentation (SSF) assay at 10% DM was 79% for the highest enzyme loading (25 FPU g−1 DM) while 69% conversion efficiency was still reached at 15 FPU g−1 DM. Total carbohydrate recoveries were high (91–100% for cellulose and 72–100% for hemicellulose) and up to 49% of the original lignin and 79% of the hemicellulose could be solubilized during wet oxidation treatment and converted into carboxylic acids mainly (total carboxylic acids = 3.1–7.4% on DM basis). Copyright © 2004 Society of Chemical Industry
Optimization of polymerase chain reaction‐amplified conditions using the uniform design method
Authors: Cao Yang , Zheng Yuanyuan , Fang Baishan
Published: July 2004

Polymerase chain reaction (PCR) is a key procedure in modern molecular biology but may be adversely affected by many factors and it is difficult to optimize reaction conditions; a technically simple and effective method to set up an optimal PCR‐amplified system is required. Uniform design (UD) is a method that enables many factors to be investigated. For example, thedhaTgene fromKlebsiella pneumoniaewas amplified and the optimization of the amplified parameters including concentration of Mg2+, annealing temperature, annealing time and number of cycles based on UD was reported. After only 12 experimental trials, an optimal PCR‐amplified result was obtained, demonstrating the value of UD for optimization of PCR. Copyright © 2004 Society of Chemical Industry
Test of flow field on the annular meridian plane in a tubular membrane separator with rotary tangential flow
Authors: Wang Cheng Duan , Jiang Guang Ming , Chen Wen Mei
Published: July 2004

Enhancement of membrane microfiltration by rotary tangential flow is a new technique, which is based on the hydrocyclone mechanism. It improved the structure of the general membrane separator and the form of the liquid suspension flowing into the separator, so as to increase membrane fluxes and decrease membrane fouling. In our research, a tubular membrane separator with rotary tangential flow was designed for the first time. The flow field characteristics of polypropylene tubular membrane microfiltration in this tubular separator were studied systematically by means of the Particle Image Velocimetry (PIV) test. Streamlines and velocity distributions of the meridian plane of the separator under different operating parameters were obtained. The velocity distribution characteristics of rotary circular tangential flow were analyzed quantitatively with the following conclusions being obtained:

In the non‐vortex area, no matter how the operating parameters (flux, entry pressure) change, the velocity near the rotary tangential flow entrance is higher than the velocity far from the entrance at the same radial coordinates. In the vortex area, generally the flow velocity of the inner vortex is lower than that of the outer vortex. At the vortex center, the velocity is the lowest, the radial velocity being generally equal to zero. In the vortex zone, the radial velocity is less than the axial velocity.

Under test conditions, the radial velocity and the axial velocity of the vortexes' borders are 1–2 times the average axial velocity in the annular gap of the membrane module. The maximum radial velocity and axial velocity of Taylor vortexes are 2–5 times the average axial velocity in the annular gap of the membrane module.

In the vortexes that formed on the meridian plane, it was found that mass transfer occurred between the inner and outer parts of the fluid. Much fluid moved from the outer vortexes into the inner ones, which was able to prevent particles blocking the membrane tube.

Copyright © 2004 Society of Chemical Industry
Performance of fractionating reactors in the absence of rate limitations
Authors: den Hollander Jeroen L , Straathof Adrie JJ , van der Wielen Luuk AM
Published: July 2004

A fractionating reactor for equilibrium‐limited reactions is studied theoretically. Reactant A is fed in the center of the countercurrent fractionating system. Product P is effectively transported with the auxiliary phase, while product Q is effectively transported with the main phase, in which the reaction takes place. Model calculations were based on partition and reaction equilibrium at all stages. These show that if the initial reactant concentration and the flow rates are properly selected, the extent of conversion will significantly exceed the corresponding batch conversion. To approach complete conversion in the fractionating reactor, and to recover both products in a pure form, net transport of reactant in either of the countercurrent directions should be prevented. However, irrespective of the number of equilibrium stages, this situation cannot be fully reached when the reactant feed stream is too large (compared with the main and auxiliary streams). Nonetheless, one of the two products may be recovered in a pure form even for such large feed streams. Copyright © 2004 Society of Chemical Industry
Separation of racemic 2,4‐dinitrophenyl amino acids on zirconia‐immobilized quinine carbamate in reversed‐phase liquid chromatography
Authors: Park Jung Hag , Lee Joon Woo , Song Young Tae , Ra Chun Sup , Cha Jin Soon , Ryoo Jae Jeong , Lee Wonjae , Kim In Whan , Jang Myung Duk
Published: July 2004

Zirconia is known to be one of the best chromatographic support materials due to its excellent chemical, thermal, and mechanical stability. A quinine carbamate‐coated zirconia was prepared as a chiral stationary phase for separation of enantiomers of DNP‐amino acids in reversed‐phase liquid chromatography. Retention and enantioselectivity of this phase were compared to those for quinine carbamate bonded onto silica. Most amino acids studied were separated on the quinine carbamate‐zirconia CSP although retention was longer and chiral selectivity was somewhat lower than on the corresponding silica CSP. Increased retention and decreased selectivity are probably due to strong non‐enantioselective Lewis acid‐base interactions between the amino acid molecule and the residual Lewis acid sites on the zirconia surface.
A preliminary approach to the separation of Leishmania cell‐surface antigens
Authors: Aksoy Nurten , Ozbilge Hatice , Keles Sait , Iriadam Mehmet , Vural Hüseyin , Akcay Fatih
Published: July 2004

The purpose of the current study was to characterize Leishmania cell‐surface antigens by two different methods established for the purification of glycoproteins and proteins, and to point out a useful approach to define their size and mass heterogeneity. L. tropica parasites were initially isolated from patients with active cutaneous leishmaniasis and were then cultured in vitro. The parasite‐cell layer was solubilised with 6 M guanidinium chloride (GuHCl) and subsequently prepared for the purification procedure. The methods used in this work were gel filtration chromatography and isopycnic density‐gradient centrifugation. Because of the presence of a substantial amount of non‐specific proteins in the culture medium, these methods were not effective alone in distinguishing these antigens. However, a good idea of their N‐glycosylated structures could be obtained by using Periodic acid‐Schiffs (PAS) and Con A lectin, and also size and mass heterogeneity. A combination of these methods effected a clear separation of the antigens. Amino acid analysis of the purified antigens was performed to positively identify them as well‐known Leishmania cell‐surface antigen gene products. The results confirmed the presence of more than one cell‐surface antigen on the Leishmania parasite and the combination of gel chromatography and density‐gradient centrifugation could be useful for their isolation.
Correct investigation of the statistic irregularities of integrated
optical waveguides with the use of the waveguide light scattering
Authors: Egorov A A
Published: July 2004

The phenomenon of the waveguide mode scattering in the
irregular planar optical waveguide is investigated. The solution
of the direct problem is fined with the help of the theory of
perturbations. The inverse waveguide scattering problem consists
in restoring of autocovariance function and determination of
irregularities' parameters by the measuring data of scattering
diagram in the far zone. The computer simulation allow approving,
that our method permits to receive an approximate correct solution
of the inverse problem with the rms error of restoring of the
given autocovariance functions no more than 35% in the presence
of high real noise (for SNR ≥ 1). The statistic parameters
of irregularities in this case are determined with the error less
than 15-30 %.
A general calculating method of photonic band gaps of two dimensional
compound lattices
Authors: Fang Yun-tuan
Published: July 2004

Basing on the plane-wave expansion method and the
calculating method of photonic band gaps of two dimensional single
lattice, we suggest a general calculating method of photonic band
gaps of two dimensional compound lattices in which the unit cell
contains some dielectric cylinders with arbitrary position,
diameter and dielectric constant. In a specific example, an
absolute photonic band gap is created in the compound lattices in
which the unit cell contains three dielectric cylinders.
Low and high order light scattering in particulate media
Authors: Meglinski I V , Romanov V P , Churmakov D Y , Berrocal E , Jermy M C , Greenhalgh D A
Published: July 2004

We present the results of a theoretical study providing
details of propagation of laser radiation within disperse randomly
inhomogeneous intermediately single-to-multiple scattering media.
A quantitative analysis of scattering orders in the transition
from single to multiple scattering is presented. Crossed
source-detector fiber optics geometry used to separate the
intensity of single scattering from higher scattering orders. The
results demonstrate good agreement between analytical and Monte
Carlo techniques. This validates the use of the Monte Carlo
approach in the intermediate single-to-multiple scattering regime.
The method used can be applied to verify analytical results
against experiment via the Monte Carlo calculations that include
imperfections of the experiment.
Soliton propagation in an absorbing three-level atomic system
Authors: Eleuch H , Elser D , Bennaceur R
Published: July 2004

We present analytic results of soliton shapes propagating in an absorbing three-level atomic system in the lambda configuration which is excited by a CW field at the Stokes transition. We find analytic relations for the control of the propagation velocity which can be influenced by the pulse width and by the intensity and polarization of the CW field.
GeV-acceleration of electron by a superintense ultrashort laser pulse
Authors: Bahari A , Taranukhin V D
Published: July 2004

New mechanism of laser acceleration of a charged
particle is discovered and explained. Particle acceleration with
focused beam of superintense ultrashort laser pulse is determined
by a combination of ponderomotive forces at rising and falling
edges of laser pulse and a longitudinal component of laser
electric field. We found that acceleration of electron, which
moves along the laser wavevector, is crucially depends on whether
or not the electron reaches the region z ⩾ z
R behind the
laser focus (here z
R is the Rayleigh length). Interpretation
of this effect consists in that the laser longitudinal electric
field at the electron trajectory in this region is a
unidirectional one (oscillatory in the case of laser linear
polarization and slowly varying in the case of laser circular
polarization). Due to this effect it is possible to overcome the
negative influence of a phase slippage in the particle-wave
interaction, which substantially suppresses electron acceleration.
We revealed also that the physical reason of a unidirectional
influence of laser longitudinal electric field on accelerating
electron in the region z ⩾ z
R consists in the difference
in phase velocities of transverse and longitudinal components of a
focused laser field. Owing to this mechanism, lasers of ultimate
present-day parameters enable electron acceleration up to the
energy ε ≃ 1 GeV. Moreover, electron
acceleration along the laser wavevector (in contrast to techniques
currently considered) is not sensitive to field initial phase
(there is no bunch effect), it is possible to accelerate slow
electrons (electrons need not to be preaccelerated to relativistic
velocities), and there are no problems with a removal of
accelerated electron from the laser field.
Anti-Stokes generation in guided modes of photonic-crystal fibers modified
with an array of nanoholes
Authors: Konorov S O , Akimov D A , Ivanov A A , Alfimov M V , Fedotov A B , Sidorov-Biryukov D A , Mel'nikov L A , Shcherbakov A V , Bugar I , Chorvat Jr. D , Uherek F , Chorvat D , Zheltikov A M
Published: July 2004

Periodic arrays of air holes with diameters ranging
from about 80 nm up to 400 nm are shown to modify intensity
profiles of guided modes in photonic-crystal fibers, suggesting
new ways of fiber dispersion engineering and modal birefringence
control. Guided modes supported by such fibers provide a high
efficiency of anti-Stokes frequency conversion for 100-fs pulses
of a Cr: forsterite laser.
All-optical integrated coding system for optical analog to digital
(A/D) converter
Authors: Rostami G , Rostami A
Published: July 2004

Kerr-like nonlinearity has key role both in monolithic
and hybrid optical integrated circuits. For digital optical signal
processing, we need all optical monolithic logic gates. For
realization of digital optical integrated circuits (DOIC), the
optical limiter is one of the important and considerable unit. In
this paper, we present a new structure for a 4-bit full optical
coding system (Limiter) for all optical analog to digital
converter (A/D) using Kerr-like nonlinear two-port ring resonator.
By controlling the system parameters such as the coupling, the
loss coefficients and the ring length, we propose a suitable
optical coding circuit, which operates similar to comparator
devices. Our proposed idea can be easily realized by integrated
optical circuit techniques (OIC).
Study of the morphological alterations to enamel and dentin
in human and bovine teeth after irradiation with Er:YAG laser
Authors: Fontana C R , Malta D A M P , Fontana U F , Sampaio J E C , Bernardes V L , de Andrade M F
Published: July 2004

Objective: The purpose of this study is to
make use of scanning electron microscopy in order to comparatively
analyze the morphological alterations to human and bovine enamel
and dentin. Earlier data: Many a morphological study
involving Er:YAG laser can be found in the literature. Still, not
a single study comparing the effects of this infrared laser in
human and bovine teeth has been reported. Materials and
Methods: Thirty-two slices of human and bovine enamel and dentin
were evenly divided into four groups. With the exception of the
control group, the samples were irradiated with Er:YAG laser,
focused at a distance of 12 mm and 10-hertz frequency, with 150,
250, and 350 mJ of output energy per pulse for 10 seconds. After
irradiation all specimens were observed under a scanning electron
microscope. Results: There was practically no
morphological difference for those samples that underwent the 150
mJ/pulse irradiation. The dentin exposed to 250 mJ had few open
dentinal tubules. These were seen in enamel after a 350 mJ
irradiation, in which the energy was able to reach the dentin.
Conclusions: The breadth of this study allows us to state
that the pattern between the species grew more heterogeneous as
the energy density was increased and that irradiation with 150
mJ/pulse resulted in greater likeness in human and bovine enamel
and dentin.
Investigation of ischemia damaging action on blood serum structure by laser
spectroscopy methods
Authors: Vlasova I M , Dolmatova E V , Koshelev V B , Saletsky A M
Published: July 2004

The laser spectroscopy methods (dynamic and static
light scattering) of light scattering register differences in
animal blood serum after a brain ischemia compared to healthy
control animal serum: firstly, size of low density lipoprotein
(LDL) of blood serum of animal after ischemia is greater than size
of serum LDL of healthy animal, secondly, density of ischemic LDL
is substantially smaller than density of healthy LDL. The obtained
results testify to possibility of use of laser spectroscopy in
diagnostic of atherosclerotic vascular diseases and for estimation
of ischemic damages.
Polypropylene Made with In‐Situ Supported Me2Si(Ind)2ZrCl2 and Me2Si(2‐Me‐Ind)2ZrCl2 Catalysts: Properties Comparison
Authors: Franceschini Fernando C. , da R. Tavares Tatiana T. , dos Santos João H. Z. , Soares João B. P.
Published: July 2004

Summary: Propylene homopolymerizations were carried out using Me2Si(Ind)2ZrCl2 and Me2Si(2‐Me‐Ind)2ZrCl2, MAO‐modified silica, and common alkylaluminum cocatalysts. Supported catalysts were prepared by the in‐situ immobilization technique. The effect of the type and concentration of alkylaluminum on propylene polymerization was evaluated using TEA (triethylaluminum), IPRA (isoprenylaluminum), and TIBA (triisobutylaluminum) as cocatalysts. The polymers were analyzed by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and scanning electronic microscopy (SEM). The effect of the type and concentration of alkylaluminum on the melting temperature and the molar mass of the polypropylene was the same for both catalysts. The polymers made with in‐situ supported catalyst had lower melting points and, in almost all polymerization conditions, higher molar masses than those produced by homogeneous polymerization. Polypropylene samples made with Me2Si(2‐Me‐Ind)2ZrCl2 had higher melting temperatures and molar masses than those made with Me2Si(Ind)2ZrCl2. SEM micrographs showed that the polymers obtained with in‐situ supported systems had a well‐defined morphology, confirming that the polymerization indeed took place onto the silica support.

SEM micrographs of polypropylene particles obtained with Me2Si(2‐Me‐Ind)2ZrCl2 in the presence of IPRA.

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SEM micrographs of polypropylene particles obtained with Me2Si(2‐Me‐Ind)2ZrCl2 in the presence of IPRA.
Oriented Quiescent Crystallization of Polyethylene Studied by USAXS
Authors: Stribeck Norbert , Almendarez Camarillo Armando , Cunis Sabine , Bayer Rüdiger K. , Gehrke Rainer
Published: July 2004

Summary: Highly oriented high‐pressure injection‐molded (HPIM) rods from polyethylene (PE) were heated until the discrete small‐angle X‐ray scattering (SAXS) had vanished. Thereafter, non‐isothermal and isothermal crystallization was investigated in situ by means of ultra small‐angle X‐ray scattering (USAXS). The orientation of the crystallites could be controlled by choice of the melt annealing temperature (shish‐kebab model: memory or self‐nucleation effect caused by stable shishs). Both the scattering patterns and the multidimensional chord distribution function (CDF) were interpreted. A three‐stage model of crystallization was also developed. This model comprises row structure nucleation, the almost statistical insertion of extended lamellae and finally the insertion of blocky crystallites. It was found that the nanostructure evolution in the isotropic fraction of the material was the same as in the highly oriented one. The lateral extension of the lamellae was largest during isothermal crystallization. The correlation among domains was increased by non‐isothermal crystallization. The shishs in the core of the HPIM rod appeared less stable than those in the shell. Lobe‐shaped reflections observed during and after quenching were not due to an orientation distribution of layer stacks, but reflected a correlation between long period and lateral extension of crystallites. During quenching, a lateral modulation of the layer peaks in the CDF grew stronger and showed the arrangement of block‐shaped crystals proposed by Strobl to be the precursors of lamellae. The thin crystals formed during rapid cooling were built from a central block surrounded by one or two rings of satellites. The long period observed in the scattering pattern during quenching is due to correlations among crystalline blocks in a chain, and not from correlations among lamellae.

USAXS scattering patterns from isothermal, oriented crystallization of HPIM‐PE material (bottom row: during final quenching after 30 min at 127 °C).

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USAXS scattering patterns from isothermal, oriented crystallization of HPIM‐PE material (bottom row: during final quenching after 30 min at 127 °C).
Oriented Quiescent Crystallization of Polyethylene Studied by USAXS.
Authors: Stribeck Norbert
Published: July 2004

Summary: In Part 1 of this series, the results of an in situ small‐angle X‐ray scattering (SAXS) study of polyethylene crystallization were presented. They showed that crystallite placement was basically a random process, from which some order is growing. This paper presents a first survey concerning the required change of paradigm. No distortion of a lattice is to be studied, but order grown on the nanometer scale must be distinguished from the stochastic case, i.e. the “car parking problem” from the field of random sequential adsorption (RSA). RSA is explored by computer simulation. The results concerning the corresponding liquid scattering are required to identify short‐range order (cf. Part 3). Processing of the simulated scattering patterns verified that the features of quasi‐random arrangement are preserved in the interface distribution function (IDF), if only the crystals are shielded by some transition layer. In a condensed random nanostructure, almost only next neighbor correlations are present. The distribution of the widths of amorphous gaps between the crystals, ha, is a truncated exponential distribution. In the scattering pattern the stochastic nanostructure can hardly be distinguished from a system with short‐range order. On the other hand, in the IDF the features of order become clear. In random systems there is no convolution polynomial based on crystalline and amorphous distributions. Only two shifted images of ha are occurring. We find that packing correlations collapse, if the crystallite thickness distribution is wide enough. In this case the pure particle scattering is a fair approximation in the IDF. This criterion is, in general, valid for technical polymer materials.

IDFs computed from the nanostructure obtained in a computer simulation of ideal random isothermal crystallization after infinite time (random car parking process). Bold line: No transition zone. Thin line: Transition zone introduced ($\mathop {\bar p}\nolimits_t /\mathop {\bar p}\nolimits_c = \mathop {\bar t}\nolimits_t /\mathop {\bar t}\nolimits_c = 0.2$). Dashed‐dotted line: A Gaussian crystalline layer thickness distribution with a standard deviation of σt = 0.2.

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IDFs computed from the nanostructure obtained in a computer simulation of ideal random isothermal crystallization after infinite time (random car parking process). Bold line: No transition zone. Thin line: Transition zone introduced ($\mathop {\bar p}\nolimits_t /\mathop {\bar p}\nolimits_c = \mathop {\bar t}\nolimits_t /\mathop {\bar t}\nolimits_c = 0.2$). Dashed‐dotted line: A Gaussian crystalline layer thickness distribution with a standard deviation of σt = 0.2.
Photochromic Copolymers Containing Bisthienylethene Units
Authors: Wang Sheng , Li Xiaochuan , Chen Bingzhi , Luo Qianfu , Tian He
Published: July 2004

Summary: Two simple yet effective strategies (Wittig condensation reaction and radical polymerization) for the synthesis of photochromic copolymers containing bisthienylethene units are presented. A new family of photochromic copolymer containing bisthienylethene and fluorophores units in the main chains was synthesized by Wittig condensation reaction. Another novel photochromic copolymer with multi‐component photochromic pendent groups was prepared by radical polymerization. Photochromism of the copolymers was investigated in solid film and in solution.

Photochromic copolymers containing bisthienylethene units.

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Photochromic copolymers containing bisthienylethene units.
Cover Picture: Macromol. Rapid Commun. 14/2004
Authors: Granville Anthony M. , Brittain William J.
Published: July 2004

Cover: This graphic duplicates the photographs of the water droplets from the manuscript. At the bottom is a simplified representation of the proposed brush rearrangement. This simplified structure is color coded for the two different monomers and corresponds to the more exact chemical structure of the diblock copolymer brush that is given above the pictures.

Further details can be found in the Communication by A. M. Granville and W. J. Brittain* on page 1298.
Quadrupole ion trap studies of fundamental organic reactions
Authors: Gronert Scott
Published: July 2004

I.
Introduction
000

 II.
General Features of Ion Traps
000

A.  Dynamic Range in Kinetics Measurements
000

B.  Temperature
000

C.  Trapping Windows
000

D.  MSn
000

E.  Reagent Gas Introduction
000

  III.
Mechanistic Studies of Organic Systems
000

A.  Substitutions and Eliminations
000

B.  Carbonyl Addition Reactions
000

C.  Electrophilic Reaction Processes
000

D.  Chemical Ionization and Related Work
000

E.  Organometallic and Related Systems
000

F.  Miscellaneous Reactions
000

   IV.
Concluding Remarks
000

References
000

Over the past several decades, quadrupole ion traps have become important instruments in the study of gas phase ion/molecule reactions. As a part of this work, they have been employed in a number of studies focused on fundamental organic reaction mechanisms. In this review, the general features and limitations of quadrupole ion traps are discussed followed by a description of representative ion trap studies of organic reaction mechanisms such as substitution, elimination, and acyl transfer reactions. © 2004 Wiley Periodicals, Inc.
A new member of the hypothalamic RF‐amide peptide family, LPXRF‐amide peptides: Structure, localization, and function
Authors: Ukena Kazuyoshi , Tsutsui Kazuyoshi
Published: July 2004

Recently, we identified a novel hypothalamic neuropeptide with a C‐terminal LPLRF‐amide sequence in the quail brain. This avian neuropeptide was shown to inhibit gonadotropin release from the cultured anterior pituitary. This peptide is the first hypothalamic peptide that inhibited gonadotropin release reported in vertebrates. We, therefore, termed it gonadotropin‐inhibitory hormone (GnIH). After this finding, we found that GnIH‐related peptides were present in the brains of other vertebrates, such as mammals, amphibians, and fish. These GnIH‐related peptides possessed a LPXRF‐amide (X = L or Q) motif at their C‐termini in all investigated animals. Mass spectrometric analyses combined with immunoaffinity chromatography were powerful techniques for the identification of mature endogenous LPXRF‐amide peptides. The identified LPXRF‐amide peptides were found to be localized in the hypothalamus and brainstem areas, and to regulate pituitary hormone release. Subsequently, cDNAs that encode LPXRF‐amide peptides were characterized in vertebrate brains. In this review, we summarize the identification, localization, and function of a new member of the hypothalamic RF‐amide peptide family, LPXRF‐amide peptides in vertebrates. Recent studies on the receptors for LPXRF‐amide peptides will also be reviewed. © 2004 Wiley Periodicals, Inc., Mass Spec Rev 24:469–486, 2005
Improving kp Data Originating From Higher Order PLP‐SEC Peaks
Authors: Kornherr Andreas , Olaj Oskar Friedrich , Schnöll‐Bitai Irene , Zifferer Gerhard
Published: July 2004

Summary: Based on certain features, especially the width of the so‐called extra peaks in the simulated chain length distribution (CLD) of polymers prepared by pulsed laser polymerization (PLP), it is calculated by which factor the positions of the higher order points of inflections and maxima deviate from the theoretical L0 data that are to be used for the evaluation of kp. These corrections, which can be put into the form of master equations, are for slightly chain length dependent termination by disproportionation or combination and cover a wide range of chain lengths and primary radical production and a reasonable range of axial dispersion σad,k, caused by the chromatographic device used in the evaluation of the chain length distribution. They can be applied either to the point of inflection on the low molecular weight side of the extra peaks as well as to the peak maximum. For usual extents of column broadening (σad,k ≈ 0.05) the mean error that is about 7% for uncorrected data from second order points of inflection is reduced to the order of 1.5% even if no assumption concerning the mode of termination is made. The situation is a little less satisfactory for the correction of the positions of the second order peak maxima. Third order peak data are a priori less falsified and yield still better results after correction. Thus the proper treatment of higher order peaks helps to extend the range of chain lengths for which highly reliable kp data can be gained from PLP experiments followed by chromatographic analysis.

Plots of l/(nL0) versus lg(L0) obtained from first order (circles), second order (triangles) and third order (squares) peaks showing uncorrected values in the left diagram and corrected values using correction functions X in the right one, both calculated for σad,k = 0.05. (+) and (×) represent ill‐defined peaks.

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Plots of l/(nL0) versus lg(L0) obtained from first order (circles), second order (triangles) and third order (squares) peaks showing uncorrected values in the left diagram and corrected values using correction functions X in the right one, both calculated for σad,k = 0.05. (+) and (×) represent ill‐defined peaks.
Nitric oxide modulation of early angiogenesis
Authors: Isenberg J. Scott
Published: July 2004

Angiogenesis is the process of new vessel formation from an existing vasculature network. In all but a few circumstances it is tightly controlled and suppressed. Precise understanding of the factors involved in modulation of angiogenesis has significant potential clinical value. One agent believed to play a role in angiogenesis is nitric oxide. However, there remain substantial uncertainties concerning the specifics of this role. The present study was undertaken to better define the role nitric oxide plays in angiogenesis associated with acute wound healing. Muscle biopsies from the pectoralis major of C57B6 mice were embedded in 500 μl of type I collagen matrix, and incubated in the presence of growth medium for 14 days. Treatment wells received L‐Arginine (2 mM), L‐NAME (300 μM), or SNAP (10–20 μM). Angiogenic response was quantified as the measure of cell migration through the matrix and as the total cells recovered from the matrix. Whole lung specimens and aortic segments served as sources of endothelial and vascular smooth muscle cells respectively for proliferation studies under similar treatment conditions. Nitric oxide was found to exert either a stimulatory or inhibitory effect on angiogenesis and cell proliferation that was subject to the assay system and specific vascular cell types present. These results suggest that the role of nitric oxide in angiogenesis is context dependent. © 2004 Wiley‐Liss, Inc. Microsurgery 24:1–7 2004.