bluuebunny/crossref_metadata_2025_split huggingface dataset:
Glucose‐6‐phosphate dehydrogenase partitioning in two‐phase aqueous mixed (nonionic/cationic) micellar systems
Authors: Rangel‐Yagui Carlota O. , Lam Henry , Kamei Daniel T. , Wang Daniel I. C. , Pessoa Adalberto , Blankschtein Daniel 
Published: March 2003

AbstractThe enzyme glucose‐6‐phosphate dehydrogenase (G6PD) plays an important role in maintaining the level of NADPH and in producing pentose phosphates for nucleotide biosynthesis. It is also of great value as an analytical reagent, being used in various quantitative assays. In searching for new strategies to purify this enzyme, the partitioning of G6PD in two‐phase aqueous mixed (nonionic/cationic) micellar systems was investigated both experimentally and theoretically. Our results indicate that the use of a two‐phase aqueous mixed micellar system composed of the nonionic surfactant C10E4 (n‐decyl tetra(ethylene oxide)) and the cationic surfactant CnTAB (alkyltrimethylammonium bromide, n = 8, 10, or 12) can improve significantly the partitioning behavior of G6PD relative to that obtained in the two‐phase aqueous C10E4 micellar system. This improvement can be attributed to electrostatic attractions between the positively charged mixed (nonionic/cationic) micelles and the net negatively charged enzyme G6PD, resulting in the preferential partitioning of G6PD to the top, mixed micelle‐rich phase of the two‐phase aqueous mixed micellar systems. The effect of varying the cationic surfactant tail length (n = 8, 10, and 12) on the denaturation and partitioning behavior of G6PD in the C10E4 /CnTAB/buffer system was investigated. It was found that C8TAB is the least denaturing to G6PD, followed by C10TAB and C12TAB. However, the C10E4/C12TAB/buffer system generated stronger electrostatic attractions with the net negatively charged enzyme G6PD than the C10E4/C10TAB/buffer and the C10E4/C8TAB/buffer systems, when using the same amount of cationic surfactant. Overall, the two‐phase aqueous mixed (C10E4/C10TAB) micellar system yielded the highest G6PD partition coefficient of 7.7, with a G6PD yield in the top phase of 71%, providing the optimal balance between the denaturing effect and the electrostatic attractions for the three cationic surfactants examined. A recently developed theoretical framework to predict protein partition coefficients in two‐phase aqueous mixed (nonionic/ionic) micellar systems was implemented, and the theoretically predicted G6PD partition coefficients were found to be in reasonable quantitative agreement with the experimentally measured ones. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 445–456, 2003.
Coextraction during reactive extraction of phenylalanine using Aliquat 336: Modeling extraction equilibrium
Authors: Pursell Mark R. , Mendes‐Tatsis M. Alcina , Stuckey David C. 
Published: March 2003

AbstractReactive liquid–liquid extraction can be used to recover hydrophilic fermentation products that would not otherwise partition into nonpolar solvents through an ion‐exchange reaction at the two‐phase interface. However, the ion‐exchange reagent may not be specific to the solute of interest and other compounds present may also be extracted. In this study, the effect on solute extraction of other compounds present in the extraction medium was investigated for phenylalanine extraction using Aliquat 336. The extent of extraction at equilibrium was modeled using the equilibrium constants for the reactions present in the process. The interaction of different species within a multicomponent medium was examined using the model and experimental results. It was found that the extent of extraction and coextraction is controlled by the thermodynamics of each extraction reaction and, due to the formation of a common product, the interaction between each of the reactions. The main competition to reactive extraction will come from hydrophobic anionic compounds that will be present in fermentation broth. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 533–542, 2003.
One‐step metal‐affinity purification of histidine‐tagged proteins by temperature‐triggered precipitation
Authors: Stiborova Hana , Kostal Jan , Mulchandani Ashok , Chen Wilfred 
Published: March 2003

AbstractThe feature of elastin‐like proteins (ELPs) to reversibly precipitate above their transition temperature was exploited as a general method for the purification of histidine (His)‐tagged proteins. The principle of the single‐step metal‐affinity method is based on coordinated ligand‐bridging between the modified ELPs and the target proteins. ELPs with repeating sequences of [(VPGVG)2(VPGKG)(VPGVG)2]21 were synthesized and the free amino groups on the lysine residues were modified by reacting with imidazole‐2‐carboxyaldehyde to incorporate the metal‐binding ligands into the ELP bio‐ polymers. Biopolymers charged with Ni2+ were able to interact with a His tag on the target proteins based on metal coordination chemistry. Purifications of two His‐tagged enzymes, β‐D‐galactosidase and chloramphenicol acetyltransferase, were used to demonstrate the utility of this general method and over 85% recovery was observed in both cases. The bound enzymes were easily released by addition of either EDTA or imidazole. The recovered ELPs were reused four times with no observable decrease in the purification performance. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 605–611, 2003.
Adding business value: a strategy for identifying and patenting environment‐related inventions and avoiding patent infringement
Authors: Higgins Brian Wm. 
Published: March 2003

AbstractFor many environmental companies, reaching financial goals is a function of identifying and protecting intellectual property assets, keeping those assets from falling into the hands of competitors and avoiding litigation disputes over the use of those assets. Recognizing that intellectual assets are valuable tangible and intangible assets of a company is the first step in maximizing the value of those assets. However, many environmental companies are not aware that some of their technologies, ideas, concepts and know‐how are potentially patentable and, therefore, fail to maximize the value of those assets by taking advantage of the limited monopolies that patent systems provide to the owners of patents. In the ever‐increasing competitive global market, companies should evaluate their intellectual assets to ensure they are adequately protecting those assets by obtaining patents for ideas that are patentable. As more patents for environmental technologies issue from patent offices around the world, however, the likelihood of infringing one of those patents can increase. Therefore, avoiding infringing others' patents while at the same time identifying and patenting the company's own technologies should be a key business strategy regardless of the size of the environmental company. Copyright © 2003 John Wiley & Sons, Ltd. and ERP Environment
Polyglycine II Nanosheets: Supramolecular Antivirals?
Authors: Tuzikov Alexander B. , Chinarev Alexander A. , Gambaryan Alexandra S. , Oleinikov Vladimir A. , Klinov Dmitry V. , Matsko Nadezhda B. , Kadykov Vasily A. , Ermishov Mikhail A. , Demin Il'ya V. , Demin Victor V. , Rye Phil D. , Bovin Nicolai V. 
Published: March 2003

AbstractTetraantennary peptides [glycinen‐NHCH2]4C can form stable noncovalent structures by self‐assembly through intermolecular hydrogen bonding. The oligopeptide chains assemble as polyglycine II to yield submicron‐sized, flat, one‐molecule‐thick sheets. Attachment of α‐N‐acetylneuraminic acid (Neu5Acα) to the terminal glycine residues gives rise to water‐soluble assembled glycopeptides that are able to bind influenza virus multivalently and inhibit adhesion of the virus to cells 103‐fold more effectively than a monomeric glycoside of Neu5Acα. Another antiviral strategy based on virus‐promoted assembly of the glycopeptides was also demonstrated. Consequently, the self‐assembly principle offers new perspectives on the design of multivalent antivirals.
The Binding Mode of Progesterone to Its Receptor Deduced from Molecular Dynamics Simulations
Authors: Mordasini Tiziana , Curioni Alessandro , Bursi Roberta , Andreoni Wanda 
Published: March 2003

AbstractAn unambiguous understanding of the binding mode of human progesterone to its receptor still eludes experimental search. According to the X‐ray structure of the ligand‐binding domain, only one (O3) of the two keto groups at the ligand ends (O3 and O20) should play a role. This result is in conflict with chemical intuition and the results of site‐directed mutagenesis experiments. Herein, we report classical molecular dynamics simulations that reveal the dynamic nature of the binding in solution, elucidate the reasons why X‐ray studies failed to determine the role of O20, and clarify the effects of the mutations. The predictive power of the force field is ensured by the consistent introduction of a first‐principles representation of the ligand.
DMACM‐Caged Adenosine Nucleotides: Ultrafast Phototriggers for ATP, ADP, and AMP Activated by Long‐Wavelength Irradiation
Authors: Geißler Daniel , Kresse Wolfgang , Wiesner Burkhard , Bendig Jürgen , Kettenmann Helmut , Hagen Volker 
Published: March 2003

AbstractThe development of new photocleavable adenosine nucleotides based on the photochemistry of [7‐(dimethylamino)coumarin‐4‐yl]methyl (DMACM) esters is described. The phototriggers liberate adenosine triphosphate (ATP), diphosphate, and monophosphate upon UV/Vis irradiation between 334 and 405 nm. The efficiency of photocleavage at long wavelengths is high as a result of a combination of appropriate quantum yields and intensive absorptivities. By using time‐resolved fluorescence spectroscopy, we determined a lower limit of 1.6×109 s−1 for the rate constant of the release of ATP from DMACM‐caged ATP. The favorable properties of DMACM‐caged ATP were confirmed in physiological studies by confocal laser scanning microscopy. We were able to uncage DMACM‐caged ATP in cultures of mouse astrocytes and in brain tissue slices from mice and were also able to measure the effect of photoreleased ATP on the cellular response of astrocytes, namely the ability of the ATP to evoke Ca2+ ion waves.
Needle Crystal Morphology Explained
Authors: Meekes H. , Boerrigter S.X.M. , Hollander F.F.A. , Bennema P. 
Published: March 2003

AbstractThe morphology of needle shaped crystals is, usually, ill‐predicted when using the common attachment energy approach. Here we explain the needle shape of triacylglycerol crystals on the basis of a two‐dimensional nucleation growth mechanism. For that the edge energies of 2D nuclei on the surfaces of the various crystal faces is determined and turns out to be much lower than expected when applying the attachment energy criteria. The edge energies are found by determining the connected nets of the various faces that follow from the crystal structure and the interaction energies between the molecules. The results are confirmed by Monte Carlo simulations.
An Analysis of Mixing in a Typical Experimental Set‐up to Measure Nnucleation Rates of Precipitation Processes
Authors: Roelands C.P.M. , Derksen J.J. , ter Horst J.H. , Kramer H.J.M. , Jansens P.J. 
Published: March 2003

AbstractMixing in a typical experimental setup to measure nucleation rates in precipitation processes was assessed. To determine these rates as a function of the driving force for concomitant polymorphs, it is necessary to perform these experiments at constant supersaturation. Therefore, the mixing time must be shorter than the time for the first nuclei to appear. For fast precipitation processes complete mixing has to be achieved within milliseconds. The mixing performance of a wide angle Y‐mixer was studied to see whether this is possible. An analysis of characteristic mixing times as a function of the average energy dissipation rate showed that turbulent dispersion of the feed streams determined the rate of the mixing process. The characteristic time for turbulent dispersion was of the same order as an arbitrarily set residence time in the Y‐mixer. However, CFD simulations of the flow showed large variation in the spatial distribution of the dissipation rate and revealed unsatisfying macromixing.
Pseudo‐polymorphic Behavior of Precipitated Calcium Oxalate
Authors: Haselhuhn F. , Kind M. 
Published: March 2003

AbstractThe precipitation of calcium oxalate pseudo‐polymorphs was studied in a Y‐mixer in series with a reaction tube. Experiments were performed with the aim to identify the decisive variables influencing the phase composition of the precipitate. Initial supersaturation, stoichiometric ratio of the lattice ions, ionic strength and pH were varied. The resulting phase distribution was determined with the help of DSC measurements. Mixing conditions were chosen such that mixing of the reactants had no influence on the experiments. Increasing supersaturation, ionic strength and pH each favor formation of the metastable calcium oxalate dihydrate over the thermodynamic stable monohydrate, although the influence of the two latter parameters is comparatively weak. If the ratio from calcium to oxalate activities was increased in the experiments a steep change in the phase composition from approximately 50 mass percent of the monohydrate to pure monohydrate was observed. Modeling of the experimental results is successful using a combination of classical nucleation theory with an equation that relates the adsorption of potential determining ions to the interfacial tension. The interfacial tension for the uncharged particles was obtained by regression from the experimental determined dependence of the phase distribution on the supersaturation.
The presence of human papillomavirus type 16/18 DNA in blood circulation may act as a risk marker of lung cancer in Taiwan
Authors: Chiou Hui‐Ling , Wu Ming‐Fang , Liaw Yu‐Ching , Cheng Ya‐Wen , Wong Ruey‐Hong , Chen Chin‐Yi , Lee Huei 
Published: March 2003

AbstractBACKGROUNDLung cancer is the leading cause of cancer death in Taiwan, and the paucity of dependable risk markers has impeded the early management of lung cancer. An association of human papillomavirus (HPV) 16/18 infection with lung cancer among nonsmoking Taiwanese women was revealed in our previous study.METHODSNested PCR was employed to detect HPV 16/18 DNA in the blood circulation of 149 lung cancer patients and 174 noncancer controls. In addition, correlation of prevalence of HPV DNA between the blood circulation and lung tumor tissue was compared from 70 sets of paired tumor tissues and peripheral blood samples available.RESULTSThe results showed that the prevalence rate of HPV 16/18 in the blood circulation of lung cancer cases was significantly higher than that of noncancer controls (47.7% vs. 12.6% for HPV 16, P < 0.0001; 30.9% vs. 5.2% for HPV 18, P < 0.0001). A significantly higher HPV 16 prevalence was detected in female lung cancer patients than that of male (57.6% vs. 41.1%, P = 0.048), as well as in cases with tumor Stages III/IV than those with tumor Stages I/II (54.6% vs. 29.3%, P = 0.006). After adjusting the effects of age, gender, and smoking status, a 6.5‐fold greater risk of lung cancer was demonstrated for those subjects with HPV Type 16 positive (95% CI 3.7–11.3, P < 0.0001), a 9.2‐fold for HPV Type 18 positive (95% CI 4.2–20.2, P < 0.0001), and a 75.7‐fold greatest risk for those with both HPV Type 16 and 18 positive (95% CI 9.8–582.1, P < 0.0001).CONCLUSIONSThese results suggested that the presence of HPV DNA in the blood circulation may serve as a feasible risk marker of lung cancer. Cancer 2003;97:1558–63. © 2003 American Cancer Society.DOI 10.1002/cncr.11191
Cost of chemotherapy‐induced thrombocytopenia among patients with lymphoma or solid tumors
Authors: Elting Linda S. , Cantor Scott B. , Martin Charles G. , Hamblin Lois , Kurtin Danna , Rivera Edgardo , Vadhan‐Raj Saroj , Benjamin Robert S. 
Published: March 2003

AbstractBACKGROUNDThe purpose of this study was to estimate the mean incremental cost of chemotherapy‐induced thrombocytopenia and the drivers of cost. Another goal was to estimate the impact of depth and duration of thrombocytopenia on the cost of thrombocytopenia.METHODSA retrospective cohort, consisting of a random sample of 75 solid tumor or lymphoma patients who developed chemotherapy‐induced thrombocytopenia (≤ 50,000 platelets per μl), was chosen. The number of each type of resource used during 217 cycles with and 300 cycles without thrombocytopenia were multiplied by the cost of each resource and summed to yield the total cost of care (in 1999 dollars from the provider's perspective).RESULTSCompared with cycles without thrombocytopenia, the mean incremental cost of thrombocytopenia was $1037 per cycle. However, 60% of cycles were usual cost, with a mean cost of thrombocytopenia of $43 per cycle less than control cycles. Twelve percent of cycles were high cost (mean incremental cost = $612 per cycle); 28% were very high cost (mean incremental cost = $3519). The excess cost during high‐cost cycles was due to high consumption of prophylactic platelet transfusions and during very high‐cost cycles to both higher platelet transfusion consumption and to a high incidence of major bleeding episodes.CONCLUSIONSAlthough thrombocytopenia is a common complication of chemotherapy, only 40% of cycles with thrombocytopenia would be considered high or very high cost. Interventions targeted at this subset of cycles could significantly reduce the cost of thrombocytopenia provided they are initiated early enough in the chemotherapy experience to be effective. Cancer 2003;97:1541–50. © 2003 American Cancer Society.DOI 10.1002/cncr.11195
Hormone replacement therapy containing progestins and given continuously increases breast carcinoma risk in Sweden
Authors: Olsson Håkan L. , Ingvar Christian , Bladström Anna 
Published: March 2003

AbstractBACKGROUNDThe authors previously reported an increased risk of breast carcinoma with longer duration of hormone replacement therapy (HRT) use. It is unclear if different types of HRT confer different risks.METHODSIn this study, a population‐based cohort of 29,508 women were interviewed during 1990–1992 to determine whether there are any differences in breast carcinoma risk according to different types and duration of HRT use.RESULTSAt the end of the follow‐up period in December 2001, the cohort constituted 298,649 person‐years. Slightly more breast carcinoma cases were seen (n = 556) than expected (n = 508.37; standardized morbidity ratio =1.09, 95% confidence interval [CI] = 1.00–1.19). Approximately 3663 women had ever used HRT. In Cox regression models, time to breast carcinoma in relation to duration and type of HRT use was analyzed, adjusting for age at menarche, age at first full‐term pregnancy, parity, age at menopause, family history of breast carcinoma, and age at interview. In women with a natural menopause, a significantly higher risk was observed for longer duration of combined continuous HRT use compared with never users (hazard ratio [HR] = 4.60, 95% CI = 2.39–8.84). Nonsignificant elevated risks also were observed for longer combined sequential (HR = 2.23, 95% CI = 0.90–5.56), gestagen only (HR = 3.74,9 5% CI = 0.94–14.97), and estriol use (HR = 1.89, 95% CI = 0.81–4.39). No increased risk was seen in women after 5 years of nonuse. When studying women who ever used only one type of HRT, even more elevated HRs for gestagen‐containing preparations were seen. The highest risks were associated with the combined continuous and gestagen‐only therapy in women with ≥ 48 months of use. Use of estradiol without progestins did not increase breast carcinoma risk significantly. The authors estimated the cumulative risk of breast carcinoma in a 50‐year‐old woman with gestagen‐containing therapies for ≥ 48 months, with a follow‐up of 10 years, to be 7% (95% CI = 5.4–11.4%) compared with 2% (95% CI = 1.6%–2.9%) for never‐users of HRT.CONCLUSIONSLonger use of HRT containing progestins significantly elevates breast carcinoma risk whereas estradiol use does not. Continued use of progestins rendered the highest risks. The yearly risk of breast carcinoma for long‐term users of progestins is of the magnitude of 50% the risk of a BRCA1 mutation carrier. Cancer 2003;97:1387–92. © 2003 American Cancer Society.DOI 10.1002/cncr.11205
Frequency of loss of hMLH1 expression in colorectal carcinoma increases with advancing age
Authors: Kakar Sanjay , Burgart Lawrence J. , Thibodeau Stephen N. , Rabe Kari G. , Petersen Gloria M. , Goldberg Richard M. , Lindor Noralane M. 
Published: March 2003

AbstractBACKGROUNDThe correlation between age at diagnosis and loss of expression of hMLH1 protein in patients with colorectal carcinoma (CRC) has not been evaluated systematically.METHODSImmunohistochemistry was performed for hMLH1 protein in tumor samples from 867 patients with CRC. The authors defined tumors arising in the cecum, ascending colon, and transverse colon as right‐sided and tumors arising in the descending colon, sigmoid colon, and rectum as left‐sided. Patients' gender, tumor location (side), and hMLH1 expression were analyzed by age groups.RESULTSThe percentage of tumors with hMLH1 expression loss increased significantly with advancing age (P < 0.0001): There were no tumors in patients age < 40 years that manifested loss of hMLH1 expression, compared with 29% of tumors that manifested loss of hMLH1 expression in patients age > 90 years. Loss of hMLH1 expression occurred more often in patients with right‐sided tumors (32.7% vs. 5.2% of patients with left‐sided tumors; P < 0.0001) and in tumors from female patients (24.3% vs. 11.5% of tumors from male patients; P < 0.0001). There was no evidence of interaction between gender and tumor location.CONCLUSIONSLoss of hMLH1 expression in patients with CRC was associated strongly with increasing age. hMLH1 expression loss was more pronounced in tumors from female patients and in tumors that originated on the right side of the colon. Loss of hMLH1 expression in right‐sided tumors occurred in nearly 50% of patients age > 90 years. This age‐related trend also was observed for males and in tumors that originated in the left colon. Cancer 2003;97:1421–7. © 2003 American Cancer Society.DOI 10.1002/cncr.11206