bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of Hydrogel Polymer on Water Productivity, Weed Control Efficiency and Yield of Broadcast-Seeded Rice
Authors: Abd El-Naby S. S. M  , El-Ghandor A. M. A. , El-Darag I. H. Abou , Mahmoud M. A. 
Published: January 2024

A field study was investigated at the Experimental Farm of Rice Research Department, Sakha Agricultural Research Station, Kafrelsheikh, Egypt during summer seasons of 2020 and 2021 to study the capability of hydrogel polymer application under different irrigation intervals and chemical weed control on water conservation and weed control under Egyptian broadcast-seeded rice (Giza 179 cv). A strip spit design with three replicates was used during the study. Three irrigation intervals (irrigation every 5 days (I1), 10 days (I2) and every 15 days (I3) were randomly devoted in horizontal plots, hydrogel polymer at rate of 20 kg ha-1 as compared to normal soil (zero hydrogel) were assigned in vertical plots, while three weed control treatments (thiobencarb at 2.38 kg ai ha-1 at 9 days after sowing (DAS) followed by (fb) bispyribac-sodium at 0.038 kg ai ha-1 + halosulfuron-methyl at 0.036 Kg ha-1 applied at 25 DAS (W1), Thiobencarb at 2.38 kg ai ha-1 fb cyhalofop-butyl at 0.286 Kg ai ha-1 + halosulfuron-methyl at 0.036 Kg ha-1 applied at 25 DAS (W2) as compared to un-treated weedy check plots (W3) were allocated in endo/sub-sub plots. Results showed that irrigation every 10 and 15 days saved about 26.4% and 35.8% of applied water, respectively, while the yield reduced by 31.8% and 56.1% respectively compared to irrigation every 5-days as average of the two seasons. The lowest dry weights of grasses and total weeds were recorded of I1, while C. difformis weed was absent under I3 during 2020 and 2021 seasons. Hydrogel polymer application conserved about 14.8% of applied water and improved rice grain yield by 16.5% as well as increased water productivity to be 0.48 kg m-3 compared to 0.32 kg m-3 for without hydrogel treatment. Hydrogel encouraged C. difformis appearance while decreased grasses and total weeds compared to without hydrogel. Sequential herbicides application W1 recorded the best weed control against grasses, C. difformis and total weeds in addition to higher WCE (91.9%) against total weeds consequently produced the highest values of rice dry matter, yield and its attributes during both seasons of study. The interaction of I1 x hydrogel x W1 achieved the highest grain yield (10.11 t ha-1) with same significance for I1 x without hydrogel x W1 (9.75 t ha-1), while I2 x hydrogel x W1 recorded the highest water productivity (0.78 kg m-3) and produced 7.63 t ha-1 of rice grain yield by increasing of 20.7% than I2 x without hydrogel x W1 as average for 2020 and 2021 seasons.
Third‐order nonlinear optical properties of polyureas and polyimide synthesized by microwave irradiation
Authors: Lu Jian‐Mei , Ji Shun‐Jun , Chen Nai‐Yong , Sun Zhen‐Rong , Zhu Xiu‐Lin , Shi Wei‐Ping , Wang Zu‐Geng 
Published: June 2003

AbstractPolymerization of benzoguanamine (BGA) and 2,4‐tolylenediisocyanate (TDI), BGA–TDI polycondensation polyurea (PU), and pyromellitic dianhydride (PMDA) in solid phase under microwave radiation was studied. In the system of TDI and BGA, the effect of microwave radiation time, the composition and concentration of monomer, the temperature, and the concentration of catalyst on the third‐order optical nonlinearities of polymer were discussed. In the system of PU and PMDA, the effect of imidization degree on third‐order optical nonlinearities was also discussed. The results showed that the prepared polymer had high third‐order nonlinear optical coefficients (PU: χ(3) = 1.174 × 10−13 esu) and fast time responses (24 ps); simultaneously, the third‐order optical nonlinearities of polymer were improved greatly by microwave radiation. The results also showed that third‐order optical nonlinearities were affected not only by the length of the polycondensate chain but also by the molecular structure, which was explained and confirmed by the computation of the AM1 semiempirical method and UV‐visible absorption spectrum. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2611–2617, 2003
Influence of fiber volume fraction and aspect ratio in resol–sisal composites
Authors: Zárate C. N. , Aranguren M. I. , Reboredo M. M. 
Published: June 2003

AbstractVegetable fibers are being used as reinforcements in polymeric matrices with a wide variety of applications. Among these fibers, sisal is of particular interest due to the high impact strength and moderate tensile and flexural properties of its derivated composites. Because of its low cost and affinity, a phenol–formaldehyde resin, resol, has been selected as the matrix to obtain resol–sisal composites. The influence of fiber length and volume fraction on flexural properties has been studied. An optimum for the fiber length as well as for the fiber volume fraction was found. The improvement of the properties occurred up to a length of about 23 mm. The use of longer fibers lead to reduced properties because they tended to curl and bend during processing. Besides, actual composite densities were lower than theoretical ones mainly due to the presence of voids. This undesirable porosity produced a reduction in flexural properties at high fiber contents. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2714–2722, 2003
Control of structure and tack properties of acrylic pressure‐sensitive adhesives designed by a polymerization process
Authors: Aymonier A. , Leclercq D. , Tordjeman P. , Papon E. , Villenave J‐J. 
Published: June 2003

AbstractFree radical emulsion polymerization of methyl methacrylate (MMA) and 2‐ethylhexyl acrylate (EHA) results in the synthesis of pressure‐sensitive adhesives (PSAs) with good tack properties. Management of both the copolymer composition and the polymerization process allows one to control the behavior of the PSA. Semicontinuous (SC) processes create polymer particles whose instantaneous composition is close to that of the feed particle The SC Mixture process (continuous feeding with comonomer blends) affords nearly homogeneous latex particles and PSA films. The SC Gradient process (separate feedings at inversely varying rates) affords heterogeneous particles and films. The Batch process leads to somewhat heterogeneous films, but the hard (MMA‐rich) microdomains are made compatible with their soft (EHA‐rich) matrix because of the assumed formation of tapered‐type copolymers. Tack measurements indicate the importance of the particle and film structures. Too much hardness or softness leads to unacceptable lacks of adhesion and cohesion, respectively. Homogeneous structures prove adequate, but their tack properties collapse with rising temperature. Heterogeneous structures, with extensive phase segregation, prove unsatisfactory because they lack adhesion and cohesion. Finally, the association of well‐balanced composition and compatible heterogeneity is the criterion for suitable PSA behavior. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2749–2756, 2003
Multicarrier spread spectrum techniques for downstream power‐line communications on low voltage grid
Authors: Fantacci Romano , Morosi Simone 
Published: June 2003

AbstractIn this paper different spread spectrum systems are proposed for broadband downstream power‐line communications (PLCs). Orthogonal frequency division multiplexing (OFDM) technique permits to greatly enhance the system throughput but can be strongly damaged by ‘hidden nodes’ situations. The introduction of suitable hybrid schemes, such as MT‐CDMA, allows to efficiently face this inconvenience by increasing system robustness.The performance of the systems considered is expressed in terms of bit error rate (BER), derived by simulations under the assumptions of frequency‐selective multipath fading channel and additive coloured gaussian noise according to the in‐building networks model, under the same overall working conditions of bandwidth occupation, transmitted power and global data rate. Copyright © 2003 John Wiley & Sons, Ltd.
Recession rates of waterfalls in Boso Peninsula, Japan, and a predictive equation
Authors: Hayakawa Yuichi , Matsukura Yukinori 
Published: June 2003

AbstractRates of waterfall recession, and major factors that influence the rate, were studied using waterfalls in Boso Peninsula, Japan. The mean rate of waterfall recession was estimated by determining the age and original location. The principal factor in determining the rate of waterfall recession is the ratio of the erosive force of stream to the bedrock resistance. This is expressed in terms of measurable variables, which include the discharge (drainage area and precipitation), the width and height of the waterfall, and the unconfined compressive strength of the bedrock. An empirical equation connecting the force/resistance ratios and the rates of waterfall recession is derived. Copyright © 2003 John Wiley & Sons, Ltd.
Effect of surface tension and depolarization field on ferroelectric nanomaterial properties
Authors: Glinchuk M. D. , Morozovskaya A. N. 
Published: June 2003

AbstractThe theory of size effects in nanocrystalline ferroelectric ceramics or nanoparticle powders allowing for surface tension and depolarization field is proposed. Surface tension was included in the free energy functional and extrapolation length was expressed via surface tension coefficient. The latter was shown to be dependent on temperature due to its relation to the dielectric permittivity of the nanoparticles. The depolarization field effect was calculated in the model taking into account the space‐charge layer on the surface.The Euler–Lagrange equation for inhomogeneous polarization was solved analytically in both paraelectric and ferroelectric phases. The temperature and size dependence of the spontaneous polarization and dielectric susceptibility of nanomaterials was obtained. The possibility to calculate these and other properties by minimization of the conventional free energy in the form of different power polarization series, but with coefficients that depend on particle size, temperature, contribution of depolarization field and surface tension coefficient, was demonstrated. A comparison with available experimental data is performed.
Temperature dependence of optical activity and circular dichroism in α‐ZnP2 crystals
Authors: Kushnir O. S. , Bevz O. A. , Polovinko I. I. , Sveleba S. A. 
Published: June 2003

AbstractThe circular birefringence related to the gyration components along and perpendicular to the optical axis and the circular dichroism of tetragonal α‐ZnP2 single crystals are determined in the temperature range 290–450 K, using universal null‐polarimetric techniques. The oscillatory temperature behaviour of the optical rotatory power and the ellipticity of light passed through the crystal in the (001) direction is quantitatively well explained by the influence of multiple reflections of light. The observed thermal hysteresis and dependence of the gyration on sample prehistory testify indirectly the availability of incommensurately modulated structure in α‐ZnP2.
Comparison of the replicability of routinely used centric relation registration techniques
Authors: Keshvad Alireza , Winstanley Raymond B. 
Published: June 2003

Purpose This study was conducted to determine statistically the most repeatable mandibular position of 3 centric relation methods.Materials and Methods Three centric relation recording methods commonly reported in the literature were selected: bimanual mandibular manipulation with a jig, chin point guidance with a jig, and Gothic arch tracing. Fourteen healthy adult volunteers (7 males and 7 females), with an average age of 26.61 ± 4.20 years and no history of extractions, temporomandibular joint dysfunction, or orthodontic treatment, were selected for the study. Accurate casts were mounted on an articulator (Denar D4A) by means of a facebow and maximum intercuspation silicone registration record. A mechanical 3‐dimensional mandibular position indicator was constructed and mounted on the articulator enabling the operator to analyze the mandibular positions in 3 spatial axes (x, anteroposterior; y, superoinferior; z, mediolateral shift). Each centric relation method was recorded four times on each subject (at baseline, 1 hour, 1 day, and 1 week at approximately the same time of day). Records were transferred to the articulator, and data were extracted using a stereomicroscope modified to accept the mandibular position indicator.Results Variability within subjects ranged from 0.03 mm (left‐side z axis for the bimanual method) to 1.6 mm (left‐side y axis for the Gothic arch method). To indicate the least variable (most repeatable) method a comparison was made using the F test. The bimanual method was the most consistent, showing between 10.11 (p= 1) and 0.438 (p= 0.005) times less variation than the Gothic arch method (the least consistent). The repeatability of the chin point guidance method was somewhere between the other 2 methods.Conclusions The results of this study showed that of the 3 centric relation methods evaluated, the bimanual manipulation method positioned the condyles in the temporomandibular joint with a more consistent repeatability than the other 2 methods, whereas the Gothic arch was the least consistent method.
Effect of cyclooxygenase‐2 inhibition on human Helicobacter pylori gastritis: mechanisms underlying gastrointestinal safety and implications for cancer chemoprevention
Authors: Scheiman J. M. , Greenson J. K. , Lee J. , Cryer B. 
Published: June 2003

SummaryCyclooxygenase (COX)‐2 expression and prostaglandin production is increased by Helicobacter pylori infection. Non‐selective COX inhibitors reduce prostaglandins and mucosal proliferation in infected mucosa and may reduce gastric cancer risk, but ulceration precludes their use. COX‐2 inhibitors cause fewer ulcers and may be chemopreventive. Physiological studies of COX‐2 inhibitors in humans with H. pylori infection have not been performed.Aim:  To study the impact of COX‐2 specific inhibition on gastric prostaglandin levels, H. pylori gastritis and proliferation.Methods: Twenty infected (eight males, 12 females; age 38 ± 1.8) and six uninfected (four males, two females; age 36 ± 3.5) healthy volunteers received rofecoxib 25 mg daily for 14 days. Endoscopic biopsies were evaluated for prostaglandin E2 (PGE2) content, gastritis and proliferation.Results: Before drug therapy, compared to uninfected, H. pylori‐infected subjects had significantly higher: (a) gastric mucosal PGE2 (pg/mg tissue) in the gastric body and antrum, (b) H. pylori score in body and antrum and (c) mid‐gland proliferation index in antrum and body. The COX‐2 inhibitor did not significantly affect PGE2 levels, gastritis scores or proliferation indices in the body or antrum in the H. pylori‐positive or ‐negative subjects.Conclusion: The predominant source of increased gastric PGE2 in H. pylori infection appears to be COX‐1‐derived. In non‐ulcerated H. pylori gastritis, COX‐2 inhibition does not affect cellular proliferation. Rofecoxib's lack of effect on gastric prostaglandin levels and proliferation in H. pylori‐infected mucosa may explain the absence of an increased ulcer risk among COX‐2 inhibitor users with H. pylori infection. The lack of significant effect on intermediate biomarkers raises uncertainty regarding the potential of specific COX‐2 inhibitors for chemoprevention of gastric cancer.
Hospital use of acid‐suppressive medications and its fall‐out on prescribing in general practice: a 1‐month survey
Authors: Parente F. , Cucino C. , Gallus S. , Bargiggia S. , Greco S. , Pastore L. , Bianchi Porro G. 
Published: June 2003

SummaryBackground: Acid‐suppressive medications are commonly used in hospitalized patients, but, to date, little is known about the overall use of these drugs in the hospital setting.Aim: To evaluate the appropriateness of acid‐suppressive therapy in a large teaching hospital in northern Italy, and the fall‐out of hospital prescription in general practice.Methods: The use of antisecretory agents was monitored for 1 month in adult patients consecutively admitted to L. Sacco University Hospital by reviewing their clinical charts. The appropriateness of each prescription was reviewed jointly by two consultant gastroenterologists.Results: A total of 46.8% of 799 hospitalized patients received acid‐suppressive therapy. Ranitidine was the most frequently used drug (44.4%), followed by pantoprazole (31.8%) and omeprazole (23.0%). Stress ulcer prophylaxis and the prevention of non‐steroidal anti‐inflammatory drug‐induced ulcer accounted for 60.4% of the indications for use. Overall, 68% of prescriptions were not appropriate as determined by consensus review; 56.4% of patients receiving unnecessary prophylactic treatment whilst in hospital were discharged on therapy, and 46% were still receiving the treatment 3 months later.Conclusions: Acid‐suppressive agents are over‐used in hospitalized patients. Most of the inappropriate hospital prescriptions are for ulcer prophylaxis in low‐risk patients. This unnecessary use may also induce inappropriate drug consumption in general practice.
Trends in the prevalence of Chagas’ disease among first‐time blood donors in São Paulo, Brazil
Authors: Sabino Ester C. , Gonçalez Thelma T. , Salles Nanci A. , Silva Guilherme R. , Chamone Dalton F. 
Published: June 2003

BACKGROUND: Screening of blood donors for Chagas’ disease is mandatory in Brazil. Data about the prevalence of Chagas’ disease among first‐time blood donors has not been previously reported. The objective of this study was to report the trends in the prevalence of Chagas’ disease among first‐time blood donors in São Paulo, Brazil according to gender, age, and type of donation.STUDY DESIGN AND METHODS: The data was obtained at Fundação Pró‐Sangue/Hemocentro de São Paulo during the period of 1996 to 2001. Samples were considered positive if they were reactive to the three serologic tests used at screening (indirect immunofluorescence, indirect hemagglutination, and EIA).RESULTS: The prevalence of Chagas’ disease was two times higher among replacement blood donors than among altruistic donors (52 vs. 25 cases/10,000). The overall prevalence among blood donors decreased at a rate of 1.86 cases per 10,000 per year. An increase in the proportion of altruistic donors and a decrease in the prevalence primarily among younger donors were observed.CONCLUSION: The prevalence of Chagas’ disease is decreasing in the São Paulo population. Differences in the socioeconomic level between altruistic and replacement donors may be the reason for the differences in the prevalence among these groups. It will be important to target for study the population of young seroreactive blood donors to better understand how new infections are occurring.
A novel approach using differential scanning calorimetry to investigate the dissolved state in aqueous solutions of polymers used for papermaking
Authors: Yamauchi Tatsuo , Tamai Nobutake 
Published: June 2003

AbstractThe size and conformations of dissolved polymer molecules of polyethylene glycol (PEG) in 5% aqueous solutions were examined through the use of differential scanning calorimetry (DSC). As long as the freezable bound water is considered to be the water enclosed by the entangled polymer chains in the solution, the appearance of the characteristics of a polymer begins to occur at a degree of polymerization (DP) between 11 and 21 and is largely completed at a DP of about 50. Assuming that the peak temperature of the DSC curve for the freezable bound water indicates the size of the entangled molecular coil, the lowering of the peak temperature with a decrease of molecular weight (MW) suggests a decrease in the size of the entangled molecular coil. The linear relationship between the peak temperature and the reciprocal of the number‐average MW suggests melting point depression as a plausible mechanism for the peak temperature lowering. Mixing of two polymers with different MWs—and thus, entangled molecular coils of different sizes—causes a kind of polymer–polymer interaction and the coil sizes change as follows. If the difference in the values of the two MWs is large, the sizes of the entangled molecular coil of each MW are brought closer to each other. The extent of approach is roughly proportional to the mixing ratio. If the difference in the values of the two MWs is not large, the original entangled molecular coils disappear and a single molecular coil of intermediate size appears instead. The size of the single intermediate molecular coil varies roughly according to the simple mixing law for the values of the two MWs. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2798–2807, 2003
In‐building power lines as high‐speed communication channels: channel characterization and a test channel ensemble
Authors: Esmailian Tooraj , Kschischang Frank R. , Glenn Gulak P. 
Published: June 2003

AbstractIn‐building power lines have often been considered as attractive media for high‐speed data transmission, particularly for applications like home networking. In this paper, we develop models for power line channels based both on theoretical considerations and practical measurements. We consider power line channel frequency response and noise models in the 1–30 MHz band and propose a number of power line test channels in which to measure the performance of power line modems. Copyright © 2003 John Wiley & Sons, Ltd.
TNF‐α induces the generation of Langerin/(CD207)+ immature Langerhans‐type dendritic cells from both CD14–CD1a– and CD14+CD1a– precursors derived from CD34+ cord blood cells
Authors: Arrighi Jean‐François , Soulas Caroline , Hauser Conrad , Saeland Sem , Chapuis Bernard , Zubler Rudolf H. , Kindler Vincent 
Published: June 2003

AbstractCD34+ cell‐derived hematopoietic precursors amplified with FLT3‐ligand, thrombopoietin and stem cell factor became, after a 6‐day induction with GM‐CSF, IL‐4 and TGF‐β1, HLA‐DR+, CD1a+, CD83–, CD86–, CD80– cells. A fraction of them expressed Langerin, Lag, and E‐cadherin, resembling epidermal Langerhans cells (LC). TNF‐α addedfor the last 3 days only marginally induced CD83 expression, but strikingly increased the proportion of immature Langerin+CD83– LC. Langerin+CD83+ and Langerin+CD83– cells were functionally distinct, the former internalizing less efficiently Langerin than the latter. Both CD1a–CD14– and CD1a–CD14+ cells sorted from FLT3‐ligand, thrombopoietin and stem cell factor cultures responded to TNF‐α by an increase of Langerin+ cells. Thus, TNF‐α rescued LC precursors irrespective of their commitment to the monocytic lineage. When added to GM‐CSF, IL‐4 and TGF β1 containing‐cultures, LPS or IL‐1β also induced significant numbers of Langerin+CD83– immature cells displaying a low allostimulatory activity, while CD40‐ligand largely promoted highly allostimulatory Langerin–CD83+ cells. Altogether, these data show that in contrast to CD40‐ligand, which induced LC maturation even in presence of TGF‐β1, nonspecific proinflammatory factors such as TNF‐α, IL‐1β or LPS, essentially induced immature LC generation, and little cell activation in the presence of TGF‐β1.