bluuebunny/crossref_metadata_2025 huggingface dataset:
Model‐Based Approach to Quantify Production Potentials of Summer Maize and Spring Maize in the North China Plain
Authors: Binder Jochen , Graeff Simone , Link Johanna , Claupein Wilhelm , Liu Ming , Dai Minghong , Wang Pu
Published: May 2008

The North China Plain (NCP) belongs to the major maize (Zea mays L.) growing areas in China. Maize yields have increased steadily since the 1980s, but in recent years average yields have stabilized around 5000 kg ha−1. The objective of this study was to quantify the production potential of summer and spring maize in the NCP. For this purpose the CERES‐Maize model was calibrated and validated. The variability caused by climate was considered by using up to 30 yr of weather data from 14 meteorological stations across the NCP. Simulations were carried out for five different soil texture. Results were linked to a Geographic Information System (GIS). The results of the model calibration and validation showed a good fit between simulated and measured yield. Average simulated grain yield for summer maize was 4800 kg ha−1 and for spring maize was 5700 kg ha−1. Yields of summer maize were limited by the duration of the growing period. In order to increase spring maize yields, two strategies were developed. The first approach was to sow spring maize at a time when water deficit was least likely to occur during the late vegetative, flowering, and grain‐filling stages. A delay in sowing of 30 d shifted maize development closer to the rainy season and increased average yield by 13%. In a second test the use of a variety with a later flowering date as a result of a longer vegetative growth led to an average increase in yield of 15%.
Solid and Skip‐Row Spacings for Irrigated and Nonirrigated Upland Cotton
Authors: Gwathmey C. Owen , Steckel Lawrence E. , Larson James A.
Published: May 2008

Producers of upland cotton (Gossypium hirsutum L.) are interested in alternative row spacings and planting patterns to improve productivity. We conducted factorial experiments for 3 yr in adjacent irrigated and nonirrigated fields at Milan, TN, of cotton grown in 25‐, 76‐ and 102‐cm rows, each planted in a solid and 2 × 1 skip‐row pattern. Narrower rows and solid plantings tended to close canopy earlier and more completely, to suppress weed growth, and to mature earlier than in wider rows and skip‐row patterns. Incomplete canopy closure in wider skip‐row spacings resulted in less weed suppression, but weed growth in skipped rows diminished with narrower row spacing. Skip‐row cotton matured later than solid planting, but this effect also diminished with narrower rows. Without irrigation, row spacing and configuration for maximum lint yield depended on growing conditions of the particular year. Under irrigation, however, solid planted 76‐cm rows consistently yielded more than either 25‐ or 102‐cm solid or skip‐row cotton. With or without irrigation, lint yields were 13 to 15% lower in 102‐cm skip‐row cotton than in 102‐cm solid planting, but yields did not differ between solid and skip‐row in narrower rows. Across years and treatments, plant density was the most influential yield component in nonirrigated cotton, but plant density and bolls plant−1 had similar influence under irrigation. Cotton producers interested in skip‐row planting should consider rows spaced 76‐cm or less to minimize weed problems and yield loss.
Simulating Gross Primary Productivity of Humid‐Temperate Pastures
Authors: Skinner R. Howard , Corson Michael S. , Gilmanov Tagir G.
Published: May 2008

Although most pasture growth models simulate many above‐ and belowground components of the plant community, calibration and validation are usually based only on periodic measurements of aboveground forage yield. This research used daily measurements of gross primary productivity (GPP) to validate the photosynthesis subroutine of the Integrated Farm System Model (IFSM). The model was calibrated for a pasture grazed by beef cattle (Bos taurus) in 2003, then validated with data from 2004 through 2006. Predicted and observed annual yield differed by 14 ± 9%, whereas predicted GPP differed from observed GPP by only 7 ± 3%. Seasonal trends in GPP were also adequately simulated, although a slight overestimation in the spring and early‐summer and underestimation in the later half of the year occurred. Overestimation occurred when wintertime temperatures were above freezing or when N availability was high following fertilizer application. Late‐season underestimation was related to low soil N availability which resulted from excessive N uptake by plants earlier in the year. Only minor adjustments in model structure were needed to improve simulation of GPP. Most adjustments involved changes in parameter values, many of which are often difficult to find or lacking in the literature. Refinement of models to accurately simulate the seasonal distribution of physiological parameters such as GPP will help ensure that model structures correctly represent the true dynamics of C assimilation and pasture growth.
A Swinging Stage to Continuously Level a Platform Balance for Field Use
Authors: Springer T. L.
Published: May 2008

Subsample wet weight is usually taken with a portable platform balance often times situated on the tailgate of a truck. Each time the vehicle is moved, the balance must be re‐leveled, and depending on the terrain, it may have to be shimmed. A “Swinging Stage” was designed, built, and tested to determine its usefulness in weighing subsamples. The Swinging Stage was constructed from common materials and takes about an hour to build. After the parts are cut and preassembled, the support hanger can be secured to a truck's stake rack and the stage suspended from it. Next, a platform balance can be placed onto the stage and initially leveled. To test the Swinging Stage performance, the vehicle was moved several times onto varying slopes and each time the balance remained level. The Swinging Stage eliminated the time and frustration of leveling a platform balance each time the vehicle was moved.
Analyzing wet weather flow management using state of the art tools
Authors: Parker Denny S. , Merlo Rion P. , Jimenez Jose A. , Wahlberg Eric J.
Published: May 2008

Optimal secondary clarifier performance is crucial to meet treatment requirements, especially when treating peak wet weather flows (PWWFs), to prevent high effluent suspended solids (ESS) concentrations and elevated sludge blankets. A state-of-the-art computational fluid dynamic (CFD) model was successfully used as a design and diagnostic tool to optimize performance for municipal wastewater treatment plants subject to significant PWWFs. Two case studies are presented. For Case Study 1, the model was used to determine the number of secondary clarifiers that will be necessary to treat future PWWF conditions for a plant under design. For Case Study 2, the model was used to identify modifications that are currently being made to increase the clarifier capacity for handling PWWF.
Prediction of alpha factor values for fine pore aeration systems
Authors: Gillot S. , Héduit A.
Published: May 2008

The objective of this work was to analyse the impact of different geometric and operating parameters on the alpha factor value for fine bubble aeration systems equipped with EPDM membrane diffusers. Measurements have been performed on nitrifying plants operating under extended aeration and treating mainly domestic wastewater. Measurements performed on 14 nitrifying plants showed that, for domestic wastewater treatment under very low F/M ratios, the alpha factor is comprised between 0.44 and 0.98. A new composite variable (the Equivalent Contact Time, ECT) has been defined and makes it possible for a given aeration tank, knowing the MCRT, the clean water oxygen transfer coefficient and the supplied air flow rate, to predict the alpha factor value. ECT combines the effect on mass transfer of all generally accepted factors affecting oxygen transfer performances (air flow rate, diffuser submergence, horizontal flow).
Examining the biodegradation of endocrine disrupting bisphenol A and nonylphenol in WWTPs
Authors: Press-Kristensen K. , Lindblom E. , Schmidt J. E. , Henze M.
Published: May 2008

The aim of this work was to examine biodegradation of the endocrine disrupting chemicals bisphenol A (BPA) and nonylphenol (NP) in activated sludge. Experiments were performed in a pilot wastewater treatment plant (WWTP) in Copenhagen, Denmark. During standard operation the BPA concentration was halved whereas the NP concentration was unchanged. Step-addition experiments showed that biomass adaptation to increased BPA and NP concentrations took 10 to more than 40 days depending on temperature, hydraulic retention time, and pre-exposure of the biomass. Mass-balance experiments showed that above 99% of the dosed BPA and 90% of the dosed NP is removed by biodegradation at steady-state. Batch experiments showed that BPA biodegradation occur solely under aerobic conditions. The work is believed to add vital knowledge to our understanding of parameters and processes governing biodegradation of EDCs in WWTPs.
Understanding road surface pollutant wash-off and underlying physical processes using simulated rainfall
Authors: Egodawatta Prasanna , Goonetilleke Ashantha
Published: May 2008

Pollutant wash-off is one of the key pollutant processes that detailed knowledge is required in order to develop successful treatment design strategies for urban stormwater. Unfortunately, current knowledge relating to pollutant wash-off is limited. This paper presents the outcomes of a detailed investigation into pollutant wash-off on residential road surfaces. The investigations consisted of research methodologies formulated to overcome the physical constraints due to the heterogeneity of urban paved surfaces and the dependency on naturally occurring rainfall. This entailed the use of small road surface plots and artificially simulated rainfall. Road surfaces were selected due to its critical importance as an urban stormwater pollutant source.

The study results showed that the influence of initially available pollutants on the wash-off process was limited. Furthermore, pollutant wash-off from road surfaces can be replicated using an exponential equation. However, the typical version of the exponential wash-off equation needs to be modified by introducing a non dimensional factor referred to as ‘capacity factor' CF. Three rainfall intensity ranges were identified where the variation of CF can be defined. Furthermore, it was found that particulate density rather than size is the critical parameter that influences the process of pollutant wash-off.
Integrated assessment of urban drainage system under the framework of uncertainty analysis
Authors: Dong X. , Chen J. , Zeng S. , Zhao D.
Published: May 2008

Due to a rapid urbanization as well as the presence of large number of aging urban infrastructures in China, the urban drainage system is facing a dual pressure of construction and renovation nationwide. This leads to the need for an integrated assessment when an urban drainage system is under planning or re-design. In this paper, an integrated assessment methodology is proposed based upon the approaches of analytic hierarchy process (AHP), uncertainty analysis, mathematical simulation of urban drainage system and fuzzy assessment. To illustrate this methodology, a case study in Shenzhen City of south China has been implemented to evaluate and compare two different urban drainage system renovation plans, i.e., the distributed plan and the centralized plan. By comparing their water quality impacts, ecological impacts, technological feasibility and economic costs, the integrated performance of the distributed plan is found to be both better and robust. The proposed methodology is also found to be both effective and practical.
Mortality in surgical units and postoperative care
Authors: Piechota Mariusz , Piechota Anna , Rysz Jacek
Published: May 2008

In the year 2005, 10 public health care institutions in Lodz contained general surgery units. The lowest mortality rate, 0,35%, was recorded in the surgical unit of University Teaching Hospital No. 5 (UH No. 5). We performed a retrospective comparative analysis of mortality in this hospital and in the two remaining university teaching hospitals, University Teaching Hospital No. 1 (UH No. 1) and University Teaching Hospital No. 2 (UH No. 2). The study was comprised of data from 18911 patients treated in these units from 01.01.2003 to 31.12.2005. The statistical data were collected by the Provincial Centre of Public Health in Lodz. The structure of the analysed units and the structure of the selected groups of diagnoses were compared. A relative structure similarity index was used to compare the structure of hospitalised patients in the analysed units, in an attempt to discover the reasons for significantly lower mortality among patients hospitalised in surgical unit of UH No. 5. A detailed analysis of the selected diagnoses and of mortality indicated that early postoperative intensive care in severely ill patients and immediate admission to the ICU, when indicated, significantly decrease mortality.
A Simple Method to Separate Quartz and Feldspar and its Application to TL/OSL Methods
Authors: Mosquera Daniel , Sánchez Jorge
Published: May 2008

In the dating of sediments by luminescence methods, to obtain a sample the purest possible as to its mineralogy determines the rest of the analytical procedures. The isolation of the sample minerals is a critical stage due to the impossibility of quantifying the relative contributions to the dose from the different minerals. In this paper we propose a non chemical method to isolate quartz from feldspar extracted from different aeolian and fluvial sediments. Grinding together quartz and feldspar grains in an agate mortar results in crushing the feldspar fraction due to its smaller hardness. Later sieving of the grinded mixture enables simple separation of both fractions. Then it is possible to save the feldspar fraction for later analyses instead of losing it as it occurs when using acid etching. Also, we study the evolution of the feldspar abundance along different purification steps with acid etching or grinding with two numerical indexes. We conclude that the grinding procedure can be introduced in the purification methods as an effective way to separate quartz from feldspar. Nonetheless, it is not an standalone procedure to obtain pure quartz and must be combined with chemical methods when the sample is rich in feldspar minerals.
The Orbibundle Miyaoka–Yau–Sakai Inequality and an Eﬀective Bogomolov–McQuillan Theorem
Authors: Miyaoka Yoichi
Published: May 2008

Let

X

be a minimal projective surface of general type deﬁned over the complex numbers and let

C ⊂ X

be an irreducible curve of geometric genus

g

. Given a rational number

α \in [0, 1]

, we construct an orbibundle

\tilde {\mathcal E}_α

associated with the pair

(X, C)

and establish the Miyaoka–Yau–Sakai inequality for

\tilde {\mathcal E}_α

. By varying the parameter

α

in the inequality, we derive several geometric consequences involving the “canonical degree”

CK_X

of

C

. Speciﬁcally we prove the following two results. (1) If

K^2_X

is greater than the topological Euler number

c_2(X)

, then

CK_X

is uniformly bounded from above by a function of the invariants

g

,

K^2_X

and

c_2(X)

(an effective version of a theorem of Bogomolov–McQuillan). (2) If

C

is nonsingular, then

CK_X ≤ 3g − 3 + o(g)

when

g

is large compared to

K^2_X

,

c_2(X)

(an affrmative answer to a conjecture of McQuillan).
Divisorial Valuations via Arcs
Authors: Ein Lawrence , de Fernex Tommaso , Ishii Shihoko
Published: May 2008

This paper shows a ﬁniteness property of a divisorial valuation in terms of arcs. First we show that every divisorial valuation over an algebraic variety corresponds to an irreducible closed subset of the arc space. Then we deﬁne the codimension for this subset and give a formula of the codimension in terms of “relative Mather canonical class”. By using this subset, we prove that a divisorial valuation is determined by assigning the values of ﬁnite functions. We also have a criterion for a divisorial valuation to be a monomial valuation by assigning the values of ﬁnite functions.
User-adaptive Reminders for Home-based Medical Tasks
Authors: Intille S. S. , Larson K. , Kaushik P.
Published: May 2008

Objectives:
We present a prototype adaptive reminder system for home-based medical tasks. The system consists of a mobile device for reminder presentation and ambient sensors to determine opportune moments for reminder delivery. Our objective was to study interaction with the prototype under naturalistic living conditions and gain insight into factors affecting the longterm acceptability of context-sensitive reminder systems for the home setting.

Methods:
A volunteer participant used the prototype in a residential research facility while adhering to a regimen of simulated medical tasks for ten days. Some reminders were scheduled at fixed times during the day and some were automatically time-shifted based on sensor data. We made a complete video and sensor record of the stay. Finally, the participant commented about his experiences with the system in a debriefing interview.

Results:
Based on this case study, including direct observation of individual alert-action sequences, we make four recommendations for designers of context-sensitive adaptive reminder systems. Captured metrics suggest that adaptive reminders led to faster reaction times and were perceived by the participant as being more useful.

Conclusions:
The evaluation of context-sensitive systems that overlap into domestic lives is challenging. We believe that the ideal experiment is to deploy such systems in real homes and assess performance longitudinally. This case study in an instrumented live-in facility is a step toward that long-term goal.
DIFFRACTION BY A UNION OF STRIPS WITH IMPEDANCE CONDITIONS IN BESOV AND BESSEL POTENTIAL SPACES
Authors: Castro Luis P. , Kapanadze David
Published: May 2008

We consider an impedance boundary‐value problem for the Helmholtz equation which models a wave diffraction problem with imperfect conductivity on a union of strips. Pseudo‐differential operators acting between Bessel potential spaces and Besov spaces are used to deal with this wave diffraction problem. In particular, these operators allow a reformulation of the problem into a system of integral equations. The main result presents impedance parameters which ensure the well-posedness of the problem in scales of Bessel potential spaces and Besov spaces.
ON THE SOLUTION OF THE STEADY‐STATE DIFFUSION PROBLEM FOR FERROMAGNETIC PARTICLES IN A MAGNETIC FLUID
Authors: Polevikov Viktor , Tobiska Lutz
Published: May 2008

A mathematical model for the diffusion process of ferromagnetic particles in a magnetic fluid is described. The unique solvability of the steady‐state particle concentration problem is investigated and an analytical expression for its solution is found. In case that the fluid is under the action of a high‐gradient magnetic field a Stefan‐type diffusion problem can arise. An algorithm for solving the Stefan‐type steady‐state problem is developed.
ROBUST NUMERICAL METHOD FOR A SYSTEM OF SINGULARLY PERTURBED PARABOLIC REACTION‐DIFFUSION EQUATIONS ON A RECTANGLE
Authors: Shishkina Lida , Shishkin Grigory
Published: May 2008

A Dirichlet problem is considered for a system of two singularly perturbed parabolic reaction‐diffusion equations on a rectangle. The parabolic boundary layer appears in the solution of the problem as the perturbation parameter ϵ tends to zero. On the basis of the decomposition solution technique, estimates for the solution and derivatives are obtained. Using the condensing mesh technique and the classical finite difference approximations of the boundary value problem under consideration, a difference scheme is constructed that converges ϵ‐uniformly at the rate O ‘N−2 ln2 N + N0 −1) , where N = mins Ns, s = 1, 2, Ns + 1 and N0 + 1 are the numbers of mesh points on the axis xs and on the axis t, respectively.
Mixed‐longitudinal growth of breastfeeding children in Moroto District, Uganda (Karamoja subregion). A loss of biological resiliency?
Authors: Gray Sandra , Akol Hellen A. , Sundal Mary
Published: May 2008

This study examines the pattern of growth, underlying growth velocity and nutritional status in a sample of thirty breastfeeding Karimojong children, aged from birth to three years. A mixed‐longitudinal structure was adopted for the study, which was carried out between August and December, 2004, in two communities in Moroto District, Uganda. Monthly anthropometric and health examinations were administered to mothers and children during this interval. Children in the study were small at birth but grew relatively rapidly for their first six months. Thereafter they experienced falling off of growth in weight, length, and head circumference. Loss of growth velocity and deterioration in nutritional status after six months was a result of physiologic stress arising from high parasite loads, introduction of inappropriate weaning foods, and psychosocial stress associated with patterns of maternal behavior. Environmental and maternal effects on child growth were exacerbated by widespread armed violence and related subsistence change in these communities. Growth of these children reflects loss of growth plasticity resulting from worsening environmental and social conditions in Moroto in 2004. Am. J. Hum. Biol., 2008. © 2008 Wiley‐Liss, Inc.
Analyzing the genetic structure of the Tepehua in relation to other neighbouring Mesoamerican populations. A study based on allele frequencies of STR markers
Authors: González‐Martín Antonio , Gorostiza Amaya , Rangel‐Villalobos Héctor , Acunha Víctor , Barrot Carme , Sánchez Cristina , Ortega Monserrat , Gené Manel , Calderón Rosario
Published: May 2008

We report data on the genetic variation of the Tepehua population based on 15 autosomal microsatellites. The Tepehua, whose language belongs to the Totonac family, are settled throughout the Sierra Madre Oriental in Mexico and constitute a group in demographic decline. The results suggest that the Tepehua population remained isolated throughout a large part of its history. Phylogenetic analyses performed with other indigenous and admixed populations of Mesoamerica allow us to address their biological history. The results suggest a genetic affinity between the Tepehua and the Huastecos due to their previous shared history, and a certain degree of differentiation from the Otomões groups and the Choles (who are of Mayan origin). A clear genetic differentiation is also apparent between native and admixed populations within the greater region of Mesoamerica. It is currently accepted that the genetic composition of the American populations fits a trihybrid model of admixture. The genetic structure based on comparison of 34 populations throughout the continent (9 indigenous and 23 admixed) using hierarchical cluster analysis with an explained variance of 61.17% suggests the existence of four large groups distinguished according to the degree of admixture between Amerindians, Europeans, and Africans. Am. J. Hum. Biol., 2008. © 2008 Wiley‐Liss, Inc.
Immunoglobulin allotypes in Southwest Asia: Populations at the Crossroads
Authors: Schanfield Moses S. , Ferrell Robert E. , Hossaini Ali A. , Gerald Sandler S. , Stevenson Joan C.
Published: May 2008

Southwest Asia has a long history of contact with Central Asian and with Sub‐Saharan African populations. Is the genetic structure of these populations reflective of these historical facts? To study this, data was generated on the immunoglobulin heavy chain (GM) and light chain (KM) allotypes from seven Arab and three non‐Arab populations in SW Asia to examine the relationship of these populations to SE European, NW Indian, Sub‐Saharan African, and Central Asian populations. Like mtDNA and Y chromosome markers, the GM haplotypes are largely continent specific making them an excellent tool for the detection of gene flow whereas the KM markers are less informative. Six of the nine GM haplotypes detected in SW Asians are Indo‐European, Sub‐Saharan African, or East Asian specific. The allotype results indicate variable but significantly higher Sub‐Saharan African gene flow in Arab populations (average 26.9%; 15.0–61.6%) vs. the non‐Arab populations (average 7.3%; 9.0–13.4%), but higher levels of Central Asian gene flow in the non‐Arab populations (average 28.8%; 10.5–48.8%) vs. the Arab populations (average 9.0%; 0.0–26.4%). Principal components analysis and hierarchical cluster analysis based on the immunoglobulin allotypes are consistent with the historical population contacts of this part of the world and reflect the power of the GM haplotypes in dissecting population relationships. However, the KM*1 frequencies were only correlated with the degree of African gene flow (Pearson r = 0.69, P = 0.026) in SW Asian populations. Am. J. Hum. Biol., 2008. © 2008 Wiley‐Liss, Inc.
Mitochondrial DNA variation and substructure among the tribal populations of Andhra Pradesh, India
Authors: Mittal Bharti , Tripathy Vikal , Aruna M. , Reddy A. G. , Thanseem I. , Thangaraj K. , Singh Lalji , Reddy B. M.
Published: May 2008

We analyzed mtDNA HVR‐I variation among six tribal populations—Andh, Pardan, Gond, Naikpod, Kolam and Chenchu—from Andhra Pradesh. These tribes belong to the Dravidian and Indo‐European linguistic group. Except for Chenchu, the rest of the tribal samples were collected from two or more than two locations. The analysis of molecular variance (AMOVA) of the sequences yields a significant FST value (0.045), suggesting a fair degree of genetic differentiation among these tribes. When the tribal samples collected from different locations were considered as subpopulations in AMOVA, it is found that the variation among the subunits within the tribal groups is smaller than among the tribes. However, when Chenchu is removed from the analysis, the magnitude of within and between groups diversity becomes similar. In the multidimensional scaling plot based on FST distances the Chenchu is found to be the extreme outlier. Exclusion of Chenchu from AMOVA analysis and multidimensional scaling plot does not result in any specific pattern of population clustering. Mismatch distribution suggest that Chenchu might have undergone a bottleneck effect and does not show evidence of past demographic expansion as shown by the other five tribal groups. A comparison of AP tribes with some other caste and tribal populations of India suggests common maternal genetic heritage. Am. J. Hum. Biol., 2008. © 2008 Wiley‐Liss, Inc.
Open‐Framework Structures of Transition‐Metal Compounds
Authors: Natarajan Srinivasan , Mandal Sukhendu
Published: May 2008

Inorganic framework solids are no longer limited to just the silicates and phosphates. Recent research has revealed that carboxylates, arsenates, sulfates, selenates, selenites, germanates, phosphites can also form such structures. One of the emerging areas combines the rich coordination chemistry of the central metal ions of many of these structures with the flexibility and functionality of the organic linkers to give rise to organic–inorganic hybrid compounds. The compounds of the transition‐metals appear to provide many variations arising from their coordination preferences, ligand geometry, and the valence state. In addition, the combination of the magnetic nature of the transition metal center with the channel structure of open frameworks suggests interesting potential applications. In this Review the synthesis, structures and properties of the various transition‐metal open‐framework compounds are discussed.
Thermal degradation behavior of poly(vinyl chloride) in presence of poly(N‐acryloyl‐N′‐cyanoacetohydrazide)
Authors: Mohamed Nadia A. , Farag Zeinab R. , Sabaa Magdy W.
Published: May 2008

The thermal degradation behavior of poly (vinyl chloride), PVC, in presence of poly(N‐acryloyl‐N′‐cyanoacetohydrazide), PACAH, has been studied using continuous potentiometric determination of the evolved HCl gas from the degradation process from one hand and by measuring the extent of discoloration of the degraded samples from the other. The efficiency of blending PACAH with dibasic lead carbonate, DBLC, conventional thermal stabilizer has also been investigated. A probable radical mechanism for the effect of PACAH on the thermal stabilization of PVC has been proposed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and characterization of novel Schiff‐base polyamides from copper/benzil bisthiosemicarbazone complexes
Authors: Ghaemy Mousa , Mighani Hossein , Behmadi Hossein
Published: May 2008

A new copper‐containing Schiff‐base diamine, benzil bis(thiosemicarbazonato)copper(II) (CuLH4), was synthesized in two steps from benzil bisthiosemicarbazone (LH6). The ligand LH6 and the complex CuLH4 were characterized with Fourier transform infrared spectroscopy, 1H‐NMR, and elemental analysis. CuLH4 was used to prepare novel polyamides. The low‐temperature solution polycondensation of the complex CuLH4 with various aromatic and aliphatic diacid chlorides afforded copper‐containing Schiff‐base polyamides with inherent viscosities of 0.25–0.36 dL/g in N,N‐dimethylformamide (DMF) and 0.75 dL/g in H2SO4 at 25°C. The polyamides were generally soluble in a wide range of solvents, such as DMF, N,N‐dimethylacetamide, tetrahydrofuran, dimethyl sulfoxide, ethyl acetate, tetrachloroethane, hexamethylene phosphoramide, N‐methylpyrrolidone, and pyridine. Thermal analysis showed that these polyamides were practically amorphous, decomposed above 270°C, and exhibited 50% weight loss at and above 400°C. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Electrochemical preparation of poly(N‐acetylaniline)/poly‐(4‐styrenesulfonic acid‐co‐maleic acid) composite film towards ascorbic acid sensing
Authors: Zhou Baineng , Wu Shouguo
Published: May 2008

Poly(N‐acetylaniline)/poly(4‐styrenesulfonic acid‐co‐maleic acid) (PNAANI/PSSMA) composite film was prepared by cyclic voltammetry (CV), and was characterized by FTIR and X‐ray photoelectron spectrum (XPS). The electroactivity of the composite film was high in neutral and basic solutions, and it had been used for amperometric determination of ascorbic acid (AA). Compared with pure PNAANI film, the catalytic activity of the composite film was much better. AA was detected amperometrically in sodium citrate buffer at a potential of 0.3 V (versus SCE). The response current was proportional to the concentration of ascorbic acid in the range of 4.7 × 10−6 to 5.0 × 10−5M and 5.0 × 10−5 to 2.5 × 10−3M, respectively, with the detection limit of 1.9 × 10−6 mol L−1 at a signal to noise ratio 3. In addition, the stability and reusability of the composite film were performed well, and it was satisfying to be used for determination of AA in real fruit juice samples. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation of nanosilica reinforced waterborne silylated polyether adhesive with high shear strength
Authors: Zhang Yang , You Bo , Huang Huang , Zhou Shuxue , Wu Limin , Sharma Anupama
Published: May 2008

Waterborne adhesives are extremely environment‐friendly but unfortunately deficient in mechanical properties. In this article, nanosilica, stemming from tetraethyl orthosilicate (TEOS), silica sol, and/or fumed silica powder, was employed to reinforce the waterborne silylated polyether adhesives. Effects of TEOS content, silica sol content, and the type and content of fumed silica on the shear strength of the adhesive were investigated using a scanning electronic microscope and an electronic instron tester and the strengthening mechanisms of different silica source were discussed. All the shear strengths of silylated polyether adhesives first increased and then decreased as TEOS content, silica sol content or fumed silica content increased. Colloidal silica particles was less efficient than fumed silica particles for reinforcing the polyether adhesive but can increase the shear strength of hydrophobic fumed silica embedded adhesive. Comparing the adhesives with the hydrophilic fumed silica (HS‐5) or the extremely hydrophobic fumed silica (TS‐720), the adhesive with moderate hydrophobic fumed silica (TS‐610) had the highest shear strength. The maximal shear strength of 2.5 MPa was achieved when TEOS, silica sol, and fumed silica were combined. It seemed that TEOS, silica sol, and fumed silica played crosslinking (with polyether chain), dispersing (for fumed silica), and reinforcing roles on waterborne adhesive, respectively. This reinforcing mechanism opened a new way to fabricate waterborne adhesives (or coatings) with high performances. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Effects of loading rate and thickness on mixed‐mode I/II fracture toughness of thermoset epoxy resin
Authors: Kanchanomai C. , Rattananon S.
Published: May 2008

The influences of loading rate and thickness on fracture behavior and mechanism of thermoset epoxy resin with polyamine hardener under mixed‐mode (mode I/II) loading have been studied at low thickness and low loading rate (LTLL), as well as high thickness and high loading rate (HTHL). Under the variation of mixed‐mode loading from mode I to mode II, fracture toughness of HTHL specimens were under plane‐strain condition. For LTLL specimens, the fracture toughness at dominated mode I loading was under plane‐stress condition, whereas those at dominated mode II loading were under plane‐strain condition. The stretched zone due to the principal stress in the normal direction to the crack plane as well as shear lips due to the Poisson contraction in the thickness direction were the main characteristic of the fracture surface of LTLL specimen tested at pure mode I loading. On the other hand, the mirror‐like fracture surface was observed for the HTHL specimen tested at pure mode I loading. Under pure mode II loading, the aligned stretched zone due to the maximum shear stress was the main characteristic of the fracture surface of LTLL specimen, whereas irregular appearance of the stretched zone was observed for the HTHL specimen. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Melt reaction of zein with glyoxal to improve tensile strength and reduce solubility
Authors: Kruger Woods Kristen , Selling Gordon W.
Published: May 2008

Glyoxal, in the presence of base, has been used to crosslink zein in a melt process involving reaction in a melt state combined with compression molding. The resulting zein articles had improved tensile strength, increasing from 34.3 to 40.6 MPa, when the amount of glyoxal was 6% by zein weight. Reduced solubility in solvents, such as acetic acid, was achieved with glyoxal amounts as low as 1%. Derivitization of zein by glyoxal required the presence of base. As little as 0.00019 mmol of NaOH per gram of zein when using 6% glyoxal gave reduced solubility. Other bases such as KOH and Ca(OH)2 also gave reduced solubility. However, these bases did not yield improvements in tensile strength. Decreases in melt temperature and processing time caused a corresponding decrease in tensile strength, but had little effect on solubility. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Plasma treatment for enhancing mechanical and thermal properties of biodegradable PVA/starch blends
Authors: Yang Sung‐Yeng , Huang Chi‐Yuan
Published: May 2008

Two series of biodegradaable polyvinyl alcohol (PVA)/starch blends, i.e., PVA with/without plasma treatment (PP/P series), were produced by single‐screw extruder. The influences of plasma pretreatment and PVA content on the tensile properties, thermal behaviors, melt flow index, and biodegradability of blends were investigated. PVA pretreated by plasma (PPVA) reacted with glycerol was found not only to mechanically strengthen the PPVA/starch blend but also to improve the compatibility of PPVA and starch. Compared with PVA/starch blends, the melt flow indices of PPVA/starch blends were improved significantly by 200–300% and their tensile strength also increased two‐to‐three‐fold. Thermogravimetry analysis (TGA) showed that the thermal stability of PPVA/starch (85/300g) blend was better than PVA/starch blend at processing temperature and outperformed than PVA and starch at high temperature. Both the PPVA/starch and PVA/starch blends finished biodegradation within 9–10 weeks in soil burial tests. The esterification reaction of PPVA and glycerol was characterized by FTIR spectroscopic measurement and TGA test. The morphologic evolutions of the blend during biodegradation were investigated carefully by scanning electron microscope (SEM) imaging. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Effect of sonolysis on kinetics and physicochemical properties of treated chitosan
Authors: Li Jin , Cai Jun , Fan Lihong
Published: May 2008

Low molecular weight chitosan with weight‐average molecular weight from 161 to 22,000Da were obtained by sonolysis. Optimal conditions for sonolysis were described. The influence of sonolysis condition and the molecular parameters of initial chitosan on the degradation rate and degradation rate constant were investigated in detail. Weight‐average molecular weight (Mw) and molecular weight dispersion (Mw/Mn) of samples were measured by gel permeation chromatography. The structure of degraded chitosan were characterized by Fourier transform infrared, X‐ray diffraction, and electrospray ionization mass spectrometry. For a given sonolysis time, the decrease in molecular weight has been found to be greatest at lowest reaction temperature and lowest chitosan concentration. Molecular weight of samples decreased exponentially with increasing sonication time at early stages. The action mode of ultrasound on the splitting of molecular chain of chitosan has been discussed. The degree of deacetylation of the main hydrolysis products almost unchanged compared with the initial chitosan. The decrease of molecular weight led to transformation of crystal structure but the chemical structures of residues were not modified. Ultrasonic treatment on chitosan is an alternative, safe method to prepare chitosan having different molecular weights, which are more suitable for biomedical and food applications. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Influence of nanoclay on urea‐formaldehyde resins for wood adhesives and its model
Authors: Lei Hong , Du Guanben , Pizzi Antonio , Celzard A.
Published: May 2008

The addition of small percentages of Na+‐montmorillonite (NaMMT) nanoclay appears to improve considerably the performance of thermosetting urea‐formaldehyde (UF) resins used as adhesives for plywood and for wood particleboard. X‐ray diffraction (XRD) studies indicated that NaMMT loses the periodic atomic structure when mixed in small proportions in the acid‐curing environment characteristic of the curing of UF resins. This can be interpreted as becoming exfoliated under such conditions. The partly crystalline structure of the ordered zones of the UF resins is maintained but at a slightly lower level. Differential scanning calorimetry (DSC) indicated that NaMMT has an accelerating effect on the curing of the UF resin. It also appears to lead to a more controlled rate of crosslinking implying a more regular hardened network. The influence of NaMMT addition was particularly noted in plywood by the increase in water resistance of the UF‐bonded panel. In the case of wood particleboard even the dry internal bond strength of the panel, a direct indication of the performance of the resin, improved with small additions of NaMMT. A hypothesis and model of the reasons why such improvement to the performance of UF resins by addition of nanoclay should occur has been presented. This is based on the application of percolation theory to the networking capability of the clay nanoplatelets. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Rhodium‐Catalyzed Asymmetric Addition of Terminal Alkynes to Diarylphosphinylallenes
Authors: Nishimura Takahiro , Guo Xun‐Xiang , Hayashi Tamio
Published: May 2008

The presence of an acid was found to be essential in the rhodium‐catalyzed asymmetric addition of terminal alkynes to diarylphosphinylallenes giving exo‐enynes in high yields with high regio‐ and enantioselectivity. The stereochemical outcome is determined at the protonolysis of the π‐allylrhodium(I) intermediate involved in the catalytic cycle.
Easily Accessible C2‐Symmetric Chiral Bicyclo[3.3.0] Dienes as Ligands for Rhodium‐Catalyzed Asymmetric 1,4‐Addition
Authors: Feng Chen‐Guo , Wang Zhi‐Qian , Tian Ping , Xu Ming‐Hua , Lin Guo‐Qiang
Published: May 2008

The synthesis of a new type of C2‐symmetric chiral diene ligands with a nonbridged bicyclic [3.3.0] backbone was successfully introduced. Using highly efficient lipase‐catalyzed transesterification and Suzuki‐coupling strategies, a broad family of enantiopure 3,6‐disubstituted bicyclo[3.3.0] dienes with different electronic and steric properties could be easily prepared. The application of these new diene ligands in the Rh‐catalyzed asymmetric 1,4‐addition of arylboronic acids to α,β‐unsaturated carbonyl compounds have been examined, and excellent enantioselectivities (up to 98 % ee) as well as good yields are achieved under very mild reaction conditions at room temperature.
Monopilegründungen von Offshore‐Windenergieanlagen – Zum Einfluss einer veränderlichen zyklischen Lastangriffsrichtung
Authors: Dührkop Jan , Grabe Jürgen
Published: May 2008

Die zyklische Horizontalbelastung von Offshore‐Monopiles für Windenergieanlagen stellt seit einigen Jahren eine sehr große Herausforderung an die Fachplaner dar, da derzeit kein abgesicherter Bemessungsansatz verfügbar ist. Die in Forschung und Entwicklung eingesetzten Methoden und Verfahren, wie Finite‐Elemente‐Analysen oder Modellversuche, fokussieren sich im ersten Ansatz auf eindirektionale Schwellbeanspruchung. Die in diesem Beitrag dargestellten Modellversuche zeigen jedoch, dass eine geringfügige Veränderung der Lastangriffsrichtung zu Pfahlkopfverschiebungen führt, die diejenigen eines eindirektional belasteten Pfahls um ein Vielfaches übersteigen. Der Pfahl arbeitet sich zyklisch auf einem Weg des geringsten Widerstands durch den Versuchsboden. Der Pfahl driftet aus der Hauptbelastungsrichtung heraus.
Injizieren von Spanngliedern mit nachträglichem Verbund mit Einpressmörtel – Ein Erfahrungsbericht
Authors: Gutsch Alex‐W.
Published: May 2008

Eine hohe Qualität des Injizierens von Spanngliedern in Vorspannsystemen ist für die Dauerhaftigkeit von Spannbetonbauteilen mit nachträglichem Verbund besonders wichtig. Schäden an Bauwerken und Spannbetonkonstruktionen zeigen, dass in manchen Fällen teilweise oder sogar vollständig unverfüllte Spannglieder die Ursache für teure Sanierungsmaßnahmen sind. Dies ist einer der Gründe dafür, dass die Herstellung des Einpressmörtels auf der Baustelle und der Einpressvorgang in die Spannkanäle selbst seit ca. sechs Jahren in Deutschland durch eine unabhängige Überwachungsstelle fremdüberwacht werden müssen.

In diesem Beitrag sollen die Erfahrungen der ersten sechs Jahre der Fremdüberwachung vorgestellt werden. Basierend auf den gewonnenen Erkenntnissen werden weiterhin Empfehlungen gegeben, wie die Herstellung und das Injizieren des Einpressmörtels in die Spannkanäle noch verbessert werden kann, um die Qualität der Einpressarbeiten insgesamt zu sichern und in der Zukunft sichere und dauerhafte Spannbetonbauwerke mit nachträglichem Verbund erstellen zu können.
Beitrag zur Berechnung der Durchbiegung von Stahlbetonbauteilen und Kritik an der ÖNORM B 4700
Authors: Schäfer Friedrich , Taheri Zia
Published: May 2008

Im Folgenden wird eine Berechnung der Durchbiegung des Stahlbetons angegeben. Diese unterscheidet sich gegenüber früheren Durchbiegungsberechnungen der ÖNORM B4700 – Stahlbetontragwerke (EUROCODE‐nahe Berechnung, Bemessung und konstruktive Durchbildung) – und ÖNORM B4200/8 dadurch, dass unter anderem Versuchsresultate berücksichtigt und die Vorgänge wirklichkeitsnah erfasst werden.

Die nach den oben genannten ÖNORMEN berechneten und überhöhten Tragwerke in Österreich sind nach Jahrzehnten noch überhöht. Dies kann unter anderem als Indiz für eine falsche Durchbiegungsberechnung angesehen werden.

Es wird daher empfohlen, die in der ÖNORM B4700 – Stahlbetontragwerke – angegebene Berechnungsmethode der Durchbiegung des Stahlbetons erstens aus der Norm zu entfernen, da diese, wie wir zeigen werden, nicht richtig ist; zweitens sich wie in der DIN 1045 auf eine Angabe der Schlankheiten zu beschränken und eventuell die Durchbiegung nach den hier angegebenen Überlegungen zu berechnen und drittens diese dem Bauingenieur zu überlassen und auf diese Weise auch die Qualen der Bauingenieure zu beenden.

Da die Normen auch den Stand der Technik darstellen und eingehalten werden müssen, stellt dies zusätzlich ein rechtliches Problem dar.

Wie gezeigt wird, beinhaltet die angegebene Methode der Berechnung der Durchbiegung in der ÖNORM B4700 schon im Ansatz schwere Gedankenfehler und falsche Voraussetzungen.
Über den Bodendruck erdgelagerter Behälter
Authors: Rosemeier Gustav‐Erich
Published: May 2008

Es werden Probleme bodengelagerter Behälter behandelt, deren Unterbauten schalenförmig ausgebildet sind. Die physikalischen Bodeneigenschaften sollen dabei denen eines elastischen Halbraums entsprechen, wobei Randkorrekturen bei den Bodenpressungen berücksichtigt werden.
15N cyclotides by whole plant labeling
Authors: Mylne Joshua S. , Craik David J.
Published: May 2008

Cyclotides are 28–37 amino acid peptides incorporating three disulfide bonds and a cyclic backbone. Their cyclic and knotted topology renders them immune to denaturation by heat or organic solvents and highly resistant to proteolysis. They have a range of interesting and potentially useful pharmaceutical properties and have been proposed as scaffolds within which peptides with drug activities can be stabilized for delivery. Some members of the family also have agricultural applications deriving from their potent insecticidal activity. Labeling peptides with the NMR‐active and stable 15N isotope facilitates a range of studies by NMR, including structural and dynamics studies and their use as tracers. However, owing to their head‐to‐tail cyclized peptide backbone labeled cyclotides are not amenable to conventional recombinant labeling strategies. We have developed an approach to overcome this limitation by growing the cyclotide‐bearing plant Oldenlandia affinis on nitrogen‐free agar media supplemented with 15N salts and obtaining complete labeling at no detriment to plant biomass. We purified the insecticidal cyclotides kalata B1 and kalata B2 as examples and provide heteronuclear single quantum coherence (HSQC) NMR spectra for each. This method of labeling cyclotides involves only a fraction of the cost of uniform labeling by solid‐phase peptide synthesis. © 2008 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 90: 575–580, 2008.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Erratum: Solvent subset selection for polymorph screening
Authors: Allesø Morten , Rantanen Jukka , Aaltonen Jaakko , Cornett Claus , van den Berg Frans
Published: May 2008

The above article (DOI: 10.1002/cem.1107) was published online on 21 January 2008. An error was subsequently identified. Figures 2a, 2b and 2c should appear as below.

The print publication will incorporate the amendment identified by this erratum notice.
Au‐Catalyzed Tandem Cyclization/[1,2]‐Alkyl Migration Reaction of Epoxy Alkynes: Synthesis of Spiropyranones
Authors: Shu Xing‐Zhong , Liu Xue‐Yuan , Ji Ke‐Gong , Xiao Hui‐Quan , Liang Yong‐Min
Published: May 2008

A novel gold‐catalyzed tandem cyclization/[1,2]‐alkyl migration process of epoxy alkynes to spiropyranones has been discovered. From this process, the construction of adjacent multiple stereocenters with a new quaternary carbon atom is achieved. The gold‐catalyzed domino process is stereospecific with respect to the migrating carbon atom. A type of unusual CC bond cleavage of epoxide systems has also been discovered, which can lead to the formation of two Z alkenes and a carbonyl functional group in one step with excellent stereoselectivity. Furthermore, this efficient domino process could be achieved in the presence of the simplest and least expensive gold catalyst [NaAuCl4]⋅2 H2O with a low catalyst loading.