bluuebunny/crossref_metadata_2025 huggingface dataset:
Behavioral assessment of children with Down syndrome using the Reiss psychopathology scale
Authors: Clark Debbie , Wilson Golder N.
Published: March 2003

The behavior of 60 children with Down syndrome (cDS), aged 4 to 21 years, was assessed by parent and teacher report using the Reiss psychopathology rating scale for dual diagnosis (mental disability plus mental illness). Standard forms contained 12 categories of abnormal behavior (e.g., Psychosis), each with five descriptive items (e.g., bizarre ideas) that could be scored as no problem, problem, and major problem (0, 1, or 2 points). Total scores for individual cDS (mean of two raters) ranged from 3 to 43 out of a potential 120 points, with a mean of 14.8 points and a standard deviation of 9.5. There were no significant differences by sex, age, or ethnicity. The highest aggregate scores among the 60 cDS were in the psychometric categories of Attention‐Deficit (156 points), Anger/Self Control (154.5), and Psychosis (109) and for component items such as communication problems (55 points) under the Psychosis category; distracted (48.5) or disobedient (42.5) under the Attention‐Deficit category; and temper tantrums (36.5), impulsive (32), or impatient (31.5) under the Anger/Self‐Control category. Agreement between parent and teacher raters was over 75% for 38 of the 60 items and above 60% for an additional 15. Selection of cDS with scores over 10 points yielded 24 families who chose parental guidance and 14 who chose professional referral. The structure of the Reiss instrument was useful for cDS, distinguishing behaviors potentially related to medical problems from true psychopathology. © 2003 Wiley‐Liss, Inc.
Stocco dos Santos X‐linked mental retardation syndrome: Clinical elucidation and localization to Xp11.3–Xq21.3
Authors: Stocco dos Santos Rita C. , Castro Nelson H.C. , Lillia Holmes A. , Beçak Willy , Tackels‐Horne Darci , Lindsey Charles J. , Lubs Herbert A. , Stevenson Roger E. , Schwartz Charles E.
Published: March 2003

Mental retardation (MR) affects an estimated 2–3% of the population. A considerable fraction of mental retardation is due to X‐linked genes. Of these genes, about 136 are responsible for syndromic X‐linked MR (XLMR). One such XLMR syndrome, Stocco dos Santos, was first described in 1991. This family was re‐visited, which allowed further delineation of the clinical phenotype. Additionally, linkage analysis was conducted, which resulted in the localization of this XLMR syndrome to the pericentric region, Xp11.3 to Xq21.1, with a maximum LOD score of 3.14 at loci AR and DXS983. © 2003 Wiley‐Liss, Inc.
Synthesis and swelling behavior of crosslinked copolymers of neutralized maleic anhydride with other monomers
Authors: You Ying‐Cai , Jiao Jing‐Liang , Li Zhen , Zhu Chang‐Ying
Published: March 2003

A series of novel copolymer superabsorbents based on maleic anhydride (MLN), acrylamide (AAM), hydroxyethyl methacrylate (HEMA), and N,N′‐methylenebisacrylamide (NMBA) were prepared by inverse‐suspension polymerization. The influence of the reaction parameters on the water absorption was investigated to improve the understanding and to identify the optimum reaction conditions. The water absorbences or swelling behaviors for these absorbents in various salt solutions and various alcohol solutions were studied. The tendency of the absorbency for these absorbents in salt and alcohol solutions is in the order Na+ > Ca2+ > Al3+ for NaCl, CaCl2, and AlCl3 aqueous solutions and a glycerol > glycol > methanol > ethanol solution, respectively. This article also explains the IR and SEM characterization of the water‐absorbing copolymers and their practical use in soil for water retention. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 12: 2725–2731, 2003
Preparation and properties of polydimethylsiloxane/polyacrylate composite latex initiated by 60Co γ‐ray irradiation
Authors: Dai Qiu , Zhang Zhicheng , Wang Feng , Liu Jie
Published: March 2003

In this study, polydimethylsiloxane (PDMS)/polyacrylate composite polymer latex was synthesized via polymerization of the acrylate monomer in the presence of vinyl‐containing PDMS seeded latex. The polymerization was initiated by 60Co γ‐ray irradiation. The morphology of the PDMS/polyacrylate composite polymer latex was a core–shell structure with PDMS as the core and polyacrylate as the shell. There was an interpenetration layer between the PDMS core and the polyacrylate shell. The composition of the vinyl‐containing PDMS and the PDMS/polyacrylate composite latex were investigated with NMR and Fourier transform infrared spectroscopy, respectively. The effect of irradiation dose on the seeded emulsion polymerization conversion is discussed. Finally, the mechanical properties of latex film, such as water‐absorption ratio, tensile strength, pendulum hardness, and heat‐decomposed temperature, were tested. The results showed that the mechanical properties of the PDMS/polyacrylate film were remarkably improved when compared to the polyacrylate film. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2732–2736, 2003
Thermal characterization of butadiene–isoprene copolymers with a 1,2/3,4 structure
Authors: Bertini Fabio , Canetti Maurizio , De Chirico Aurelio , Ricci Giovanni
Published: March 2003

Two series of butadiene–isoprene copolymers with a 1,2 and/or 3,4 structure were prepared at different polymerization temperatures, using CrCl2(dmpe)2‐MAO as a catalyst system. Copolymerization carried out at higher temperature resulted in polymers in the whole range of monomeric ratio, from the highly crystalline 1,2‐syndiotactic polybutadiene to the amorphous 3,4‐polyisoprene. The molar composition of the butadiene–isoprene copolymers and the syndiotactic index of the butadiene sequences, represented as molar fraction of the syndiotactic pentads, were evaluated by carbon‐13 nuclear magnetic resonance spectroscopy. The thermal behavior of the copolymers was investigated by differential scanning calorimetry. Nonisothermal crystallization kinetics were characterized by Ziabicki and Avrami methods as modified by Jeziorny. The crystallization and melting temperatures and the enthalpy of fusion of the copolymers were in good correlation with the syndiotactic index of butadiene sequences. The index was influenced by polymerization temperature and composition of butadiene–isoprene copolymers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 12: 2737–2743, 2003
Poly(para‐dioxanone) and poly(L‐lactic acid) blends: thermal, mechanical, and morphological properties
Authors: Pezzin A. P. T. , Van Ekenstein G. O. R. Alberda , Zavaglia C. A. C. , Ten Brinke G. , Duek E. A. R.
Published: March 2003

Blends of two semicrystalline polymers, poly(L‐lactic acid) (PLLA) and poly‐p‐dioxanone (PPD) have been prepared by solvent casting in different compositions. Thermal, morphological, and mechanical properties of the blends were studied using modulated differential scanning calorimetry, wide‐angle X‐ray diffractometry, scanning electron microscopy (SEM), polarizing light microscopy (PLM), and tensile tests. Thermal analysis showed two glass transition temperatures nearly constant and equal to the values of the homopolymers and constant values of melting temperature (Tm) for all blend compositions, suggesting that both polymers are immiscible. The PLM and SEM observations validated these results, and showed the different morphology obtained by changing the composition of the blend. The blends 40/60, 50/50, and 60/40 presented a clearly macroseparated system, while the 20/80 and 80/20 blends presented better homogeneity, probably due to the low amount of one component in the other. It was found by PLM that PPD is able to crystallize according to a spherulitic morphology when its content is above 40%. Under this content, the crystallization of PPD is hardly observed. The blend 20/80 is more flexible, and tough material and neck formation during elongation is also observed, due to PPD, which may act as a plasticizer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 12: 2744–2755, 2003
Synthesis and rapid expansion in supercritical carbon dioxide through porous sintered metal plate of poly(1,1,2,2‐tetrahydroperfluorodecyl acrylate)
Authors: Dong Qingzhi , Young Thomas M.
Published: March 2003

Poly(1,1,2,2‐tetrahydroperfluorodecyl acrylate) [poly(TA‐N)] was synthesized in dry benzene using AIBN as an initiator at 60°C. The effects of the monomer concentration (Cm), initiator concentration (Ci), and reaction time on the polymerization were investigated. The results of DSC and TGA showed that when the Ci remains constant, the higher the Cm value is, the better the thermal character for the product in the range of experiments. When the reaction was conducted for 30 h, polymerization is almost completed. The Ci should remain lower than 0.25 g/100 g monomer when the Cm is lower than 15 g/L. When the Cm is higher than 15 g/L, the Ci should be increased slightly. When the Cm remains constant, it was observed that an increase in the Ci increases the yield (mass of polymer after reaction/mass of monomer before reaction). On the other hand, the melting (Tm) and decomposition (Td) temperatures of the reaction product decrease, except when the Cm reaches 20 g/L and the reaction time is 30 h. High purity CO2 was continuously pumped using a high pressure syringe pump. Rapid expansion of poly(TA‐N) in supercritical CO2 happened under control through a porous sintered metal plate. The poly(TA‐N) morphology was analyzed with a scanning electron microscope. An amorphous polymer was formed at a preexpansion temperature of 45°C. Fibers were formed at temperatures of around 60–80°C. An increase of the temperature slightly increases the particle size. At 105°C, most of the particles are spheres and dendrites. The corresponding CO2 flow rate upon expansion was 2.5–5.0 ± 0.3 L/min (STP) and the pressure drop was 2 MPa. At the higher CO2 flow rate, the spheres and dendrites became smaller. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2763–2768, 2003
Depolymerized chitosan nanoparticles for protein delivery: Preparation and characterization
Authors: Janes K. A. , Alonso M. J.
Published: March 2003

In this article we describe our preliminary work involving the use of depolymerized, low molecular weight chitosan nanoparticles as carriers for proteins and peptides. We hypothesized that the molecular weight of chitosan could favorably modulate the particle and protein release characteristics for the delivery of certain bioactive macromolecules. Our primary objectives were to develop nanoparticle formulations that were stable and reproducible across a range of chitosan molecular weights and then characterize the physicochemical and in vitro release properties as functions of the polymer size. Using depolymerized fragments generated by NaNO2 degradation of different chitosan salts, we prepared nanoparticle formulations based on ionotropic gelation with sodium tripolyphosphate (TPP). Regardless of the formulation, the nanoparticle size decreased with decreasing molecular weight and the ζ‐potential values remained unchanged. Similar comparisons were made with the encapsulation of insulin and tetanus toxoid as model proteins. The results indicated that the quantity of TPP in a given formulation has a greater effect on the protein encapsulation than the chitosan molecular weight. In fast release environments (i.e., buffered media), there was no significant molecular weight effect that could be discerned. These data lead to the conclusion that, under these experimental conditions, the chitosan molecular weight has a measurable effect on the particle properties, although this effect is modest relative to other formulation parameters (e.g., TPP content, type of protein loaded). Because these subtle differences could have dramatic effects physiologically, work is currently underway to elucidate the possible applications of depolymerized chitosans for peptide delivery in vivo. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 12: 2769–2776, 2003
Antibacterial and biodegradable properties of polyhydroxyalkanoates grafted with chitosan and chitooligosaccharides via ozone treatment
Authors: Hu S.‐G. , Jou C.‐H. , Yang M.‐C.
Published: March 2003

Acrylic acid was grafted to ozone‐treated poly(3‐hydroxybutyric acid) (PHB) and poly(3‐hydroxybutyric acid‐co‐3‐hydroxyvaleric acid) (PHBV) membranes. The resulting membranes were further grafted with chitosan (CS) or chitooligosaccharide (COS) via esterification. These CS‐ or COS‐grafted membranes showed antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, methicilin‐resistant Staphylococcus aureus (MRSA), and S. aureus. The antibacterial activity to E. coli was the highest, whereas the antibacterial activity to MRSA was the lowest among these four bacteria tested. Acrylic acid grafting can increase the biodegradability with Alcaligens faecalis, whereas CS and COS grafting can reduce the biodegradability. In addition, CS‐grafted PHBV membrane showed higher antibacterial activity and lower biodegradability than COS‐grafted PHBV membrane. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 12: 2797–2803, 2003
Effects of rosin‐type nucleating agent and low density polyethylene on the crystallization process of polypropylene
Authors: Li Chuncheng , Li Wei , Wang Hui , Zhang Dong , Li Zhenyi
Published: March 2003

In this article, the influence of rosin‐type nucleating agent (Nu–Na) and low density polyethylene (LDPE) on the crystallization process of polypropylene (PP) from the melt state was studied by differential scanning calorimeter and polarization microscope. It was found that LDPE obstructed the crystallization of PP, decreased the crystallization rate of PP. The rosin‐type nucleating agent Nu–Na substantially improved the rate of crystallization, and decreased the size of spherulites also. The cooperative effect of LDPE and Nu–Na made the crystallization rate of PP increase greatly, the spherulites of PP became much smaller and dispersed more uniformly, and the transparency of PP was further improved evidently. The crystallization temperature (Tc) and melting temperature (Tm) of PP and LDPE in PP/LDPE/Nu–Na (97:3:0.5) were not affected by the number of mixed passes—the nuclei migration from PP to PE had not happened in the mixed passes. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2804–2809, 2003
Influence of temperature on the ultrasonic degradation of poly(vinyl acetate) and poly(vinyl chloride)
Authors: Chattopadhyay Sujay , Madras Giridhar
Published: March 2003

This study investigates the effect of temperature on the ultrasonic degradation of polyvinyl acetate and polyvinyl chloride in chlorobenzene. The time evolution of molecular weight distribution was determined using gel permeation chromatography. Continuous distribution kinetics was used to obtain the degradation rate coefficients. The rate coefficients decrease with increasing temperature, and this is attributed to the increase of vapor pressure and the decrease of kinematic viscosity. The degradation rate coefficient also changes sharply near the glass transition temperature, indicating that this factor may play a role in the degradation process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 12: 2818–2822, 2003
Thin copper foil heater for measuring the thermal conductivity of polymers
Authors: Kazeminejad H.
Published: March 2003

A new and rather simple apparatus is described for measuring the thermal conductivity of insulating materials. The technique employs a double‐sided, copper‐coated plastic sheet, known as a printed circuit board, to generate a nearly uniform wall heat flux. Heating is achieved by passing an electrical current through the copper coating. Identical sample slabs are placed against opposite sides of the heater, and the combination is placed in a bath having constant and uniform temperature. When thermal equilibrium is reached, the temperature drops across the central portions of the sample slabs are measured with thermocouples. The one‐dimensional form of Fourier heat transfer equation is used to compute thermal conductivity from the observed quantities. In preliminary tests with polymer materials, equilibrium is reached within half an hour. It is estimated that the apparatus is capable of giving measurements accurate to within 5%, and experimental results are consistent with this estimate. Thermal conductivity values are reported for pure polyethylene (PE) and PE mixed with aluminum powder and carbon black. Also reported is the thermal conductivity of pure polycarbonate (PC) and PC mixed with carbon black. The results obtained with the present apparatus are consistent with previous findings. The characteristics of the apparatus make it especially suitable for academic laboratory instruction and for low temperature thermal conductivity measurements. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 12: 2823–2827, 2003
Surface chemistry and moisture sorption properties of wood coated with multifunctional alkoxysilanes by sol‐gel process
Authors: Tshabalala Mandla A. , Kingshott Peter , VanLandingham Mark R. , Plackett David
Published: March 2003

Sol‐gel surface deposition of a hydrophobic polysiloxane coating on wood was accomplished by using a mixture of a low molecular weight multifunctional alkoxysilane, methyltrimethoxysilane (MTMOS), and a high molecular weight multifunctional alkoxysilane, hexadecyltrimethoxysilane (HDTMOS). Investigation of the surface chemistry and morphology of the wood specimens by means of ATR–FTIR, energy‐dispersive X‐ray analysis, X‐ray photoelectron spectroscopy, SEM, and atomic force microscopy indicated that the sol‐gel process results in deposition of polysiloxane networks that are bonded to the wood by polycondensation with surface hydroxyl groups. The surface hydroxyl groups involved in the bonds appear to be located predominantly on the cellulose component of the wood. The sol‐gel deposit on the wood substrates lowered the rates of water and water vapor sorption. The low molecular weight MTMOS apparently penetrated the outer surface layers of the wood and condensed with hydroxyls that may not be readily accessible to the high molecular weight HDTMOS. Once attached to such sites, it is reasonable to assume that some of these surface derivatives of MTMOS condensed with other molecules of MTMOS and HDTMOS with a long hydrocarbon chain to form a polysiloxane network that is hydrophobic. The ultimate effect of the sol‐gel deposit can therefore be regarded as not only to decrease the surface concentration of hydrogen‐bonding sites, but also to stereochemically hinder the formation of hydrogen bonds between such sites and water molecules. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2828–2841, 2003
Toward consistent and productive complex media for industrial fermentations: Studies on yeast extract for a recombinant yeast fermentation process
Authors: Zhang Jinyou , Reddy Jayanthi , Buckland Barry , Greasham Randolph
Published: March 2003

Yeast extract (YE) is commonly used as a key component in the complex media for industrial fermentations. However, the lot‐to‐lot variation of this raw material frequently requires extensive “use testing” of many lots to identify only the few that support desired fermentation performance. Through extensive fermentation studies and chemical analyses, we have identified adenine and two metabolizable carbon sources, trehalose and lactate, as the principle components in YE that affect the production of a recombinant protein antigen by a yeast strain. Adenine is required for culture growth and the relationship between biomass and measured adenine can be expressed by a Michaelis‐Menten model, while the slowly metabolized trehalose serves to maintain the energy supply to the continued antigen synthesis. The rapidly utilized lactate exerts an indirect positive effect by sparing some of the accumulated ethanol from being consumed for growth to being utilized in the product formation. The effects of these YE components are mutually dependent. Based on the database generated from 40 lots at laboratory scale, a relatively high level of carbon sources in YE (trehalose plus lactate, >9.5% w/w) and an intermediate level of adenine (0.14–0.24% w/w) appear to be the minimal requirement of a good lot for this recombinant yeast fermentation. Many poor lots were improved in lab fermenters by rational supplementation of trehalose, lactate, or adenine to compensate for their insufficiencies. At the large production scale, predictions based on adenine and trehalose/lactate contents in various YE lots used correlated reasonably well with culture growth and antigen yield, illustrating the feasibility of such a simple chemical/biochemical analysis as a rapid and reliable initial screening tool. Without incurring any compositional change to an established manufacturing medium, this study demonstrates an effective approach to achieve consistency in fermentations employing complex nutrients and to improve fermentation productivities supported by suboptimal lots of raw material. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 640–652, 2003.
Generally applicable fed‐batch culture concept based on the detection of metabolic state by on‐line balancing
Authors: Jobé Anna Marya , Herwig Christoph , Surzyn Martin , Walker Bernhard , Marison Ian , von Stockar Urs
Published: March 2003

In many microorganisms, flux limitations in oxidative metabolism lead to the formation of overflow metabolites even under fully aerobic conditions. This can be avoided if the specific growth rate is controlled at a low enough value. This is usually accomplished by controlling the substrate feeding profile in a fed‐batch process. The present work proposes a control concept which is based on the on‐line detection of metabolic state by on‐line calculation of mass and elemental balances. The advantages of this method are: 1) the check of measurement consistency based on all of the available measurements, 2) the minimum requirement of a priori knowledge of metabolism, and 3) the exclusive use of simple and established on‐line techniques which do not require direct measurement of the metabolite in question. The control concept has been linked to a simple adaptive controller and applied to fed‐batch cultures of S. cerevisiae and E. coli, organisms which express different overflow metabolites, ethanol and acetic acid, respectively. Oxidative and oxidoreductive states of S. cerevisiae and E. coli cultures were detected with high precision. As demonstrated by the formation of acetic acid in E. coli cultures, metabolic states could be correctly distinguished for systems for which traditional methods, such as respiratory quotient (RQ), are insensitive. Hence, it could be shown that the control concept allowed avoidance of overflow metabolite formation and operation at maximum oxidative biomass productivity and oxidative conversion of substrate into biomass. Based on mass and elemental balances, the proposed method additionally provides a richness of additional information, such as yield coefficients and estimation of concentrations and specific conversion rates. These data certainly help the operator to additionally evaluate the state of the process on‐line. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 627–639, 2003.
Economically pertinent continuous amide formation by direct lipase‐catalyzed amidation with ammonia
Authors: Slotema Wouter F. , Sandoval Georgina , Guieysse David , Straathof Adrie J.J. , Marty Alain
Published: March 2003

An economically pertinent process for the lipase‐catalyzed synthesis of amides was developed. A continuous plug flow reactor was used. The model reaction was the production of oleamide, a lubricant and anti‐slip agent, via direct Candida antarctica lipase B‐catalyzed amidation of oleic acid with ammonia. Of all solvents tested, 2‐methyl‐2‐butanol was found to respond optimally to the demands formulated in our specifications. A continuous conversion of oleic acid into oleamide of 85% was obtained. A productivity of 4.5 tons oleamide per kg of enzyme per year was calculated, indicating a contribution of enzyme to the product price of only 4%. The volumetric productivity, 100 g · L−1 · h−1, is 4 to 100 times higher than in literature procedures. A simple crystallization procedure leads to 99% purity. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 664–669, 2003.
Physiological responses of chemostat cultures of Aspergillus niger (B1‐D) to simulated and actual oxidative stress
Authors: Bai Zhonghu , Harvey Linda M. , McNeil Brian
Published: March 2003

The physiological responses of chemostat cultures of the filamentous fungus, Aspergillus niger (B1‐D) to simulated and actual oxidative stress, imposed respectively by addition of exogenous menadione (MD; a superoxide radical generating reagent) and gassing the culture with oxygen enriched air (25%, 50%, 75%, and 100% [v/v]), were examined. Changes in the levels of intracellular superoxide anions and defensive enzyme activities, such as catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx), were monitored, together with glutathione and respiratory activity in both the dynamic phase and when a new steady state was established. Culture response to MD addition was distinct from that upon exposure to enriched oxygen conditions, in that MD caused elevated levels of intracellular protein, whereas oxygen enrichment caused reduced protein content, especially at low dilution rates. An unexpectedly low level of superoxide radical was found in oxygen‐enriched steady‐state cultures (⩾50%) at a range of dilution rates, which was not caused by elevated SOD activity. Under these conditions, it was noted that the ratio of rotenone‐insensitive/total respiration increased, suggesting increased activity of the alternative respiratory pathway. This may have had the effect of reducing the endogenous generation of superoxide radicals under oxygen rich conditions, but also may have reduced the ATP yield due to the non–proton‐pumping nature of the alternative respiratory pathway. Thus, the negative culture effects noted in many studies at high oxygen levels may not simply be due to elevated endogenous superoxide generation, but could be in part due to the consequences of metabolic changes in the culture that seek to minimize superoxide generation. The dynamic culture response was characterized by rapid elevation of intracellular superoxide anions and associated protective enzymes, especially SOD, and was clearly distinct from the adaptive response just described. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 691–701, 2003.
Metabolic engineering of Lactobacillus fermentum for production of mannitol and pure L‐lactic acid or pyruvate
Authors: Aarnikunnas Johannes , von Weymarn Niklas , Rönnholm Kent , Leisola Matti , Palva Airi
Published: March 2003

For production of mannitol in combination with pure L‐lactic acid or pyruvate, the D‐ and L‐lactate dehydrogenase genes (ldhD and ldhL) of a mannitol‐producing Lactobacillus fermentum strain were cloned and stepwise inactivated. For inactivation of both ldh genes by a gene replacement technique, deletion constructs removing a 0.4‐kb fragment from the promoter and the 5′ end region of the ldh genes were used. The first inactivation mutant, designated L. fermentum GRL1030, carried the deletion in ldhD (ΔldhD). A double mutant, ΔldhD‐ΔldhL, was constructed by the inactivation of the ldhL gene of strain GRL1030, resulting in strain L. fermentum GRL1032. The correctness of the both mutants was confirmed at the DNA level by polymerase chain reaction, as shown by the absence of ldh transcripts by northern blotting and as a lack of the corresponding enzyme activity. In bioreactor cultivations, the single mutant GRL1030 produced mannitol and L‐lactic acid as expected. Mannitol and lactic acid yields and productivities were practically unaffected by deletion of the ldhD gene. The double mutant GRL1032 produced mannitol and pyruvate as expected. However, although the yield of mannitol from fructose remained high, its volumetric productivity was reduced. The double mutation negatively affected the glucose consumption rate, resulting in reduced cellular growth. In addition to pyruvate, the double mutant produced 2,3‐butanediol. More surprisingly, some lactic acid was still produced. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 653–663, 2003.
Cyclic fed‐batch culture for production of human serum albumin in Pichia pastoris
Authors: Bushell M. E. , Rowe M. , Avignone‐Rossa C. A. , Wardell J. N.
Published: March 2003

Simple cyclic fed‐batch culture (cfbc), consisting of a constant medium feed with periodic withdrawals of culture, resulted in a product yield (13.4 mg protein per gram biomass) similar to that obtained using the complex multiphase industrial production strategy (13.7 mg protein per gram biomass). In cfbc, productivity was ultimately limited by the rate at which the cells could assimilate methanol. Glycerol was inhibitory to growth at high concentrations. However, product yield continued to increase as the glycerol concentration was increased. In chemostat culture, dissolved oxygen concentration influenced product yield independently of any detectable influence on cell growth. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 678–683, 2003.
Optimization‐based framework for inferring and testing hypothesized metabolic objective functions
Authors: Burgard Anthony P. , Maranas Costas D.
Published: March 2003

An optimization‐based framework is introduced for testing whether experimental flux data are consistent with different hypothesized objective functions. Specifically, we examine whether the maximization of a weighted combination of fluxes can explain a set of observed experimental data. Coefficients of importance (CoIs) are identified that quantify the fraction of the additive contribution of a given flux to a fitness (objective) function with an optimization that can explain the experimental flux data. A high CoI value implies that the experimental flux data are consistent with the hypothesis that the corresponding flux is maximized by the network, whereas a low value implies the converse. This framework (i.e., ObjFind) is applied to both an aerobic and anaerobic set of Escherichia coli flux data derived from isotopomer analysis. Results reveal that the CoIs for both growth conditions are strikingly similar, even though the flux distributions for the two cases are quite different, which is consistent with the presence of a single metabolic objective driving the flux distributions in both cases. Interestingly, the CoI associated with a biomass production flux, complete with energy and reducing power requirements, assumes a value 9 and 15 times higher than the next largest coefficient for the aerobic and anaerobic cases, respectively. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 670–677, 2003.
The influence of transport phenomena during high‐pressure processing of packed food on the uniformity of enzyme inactivation
Authors: Hartmann Chr. , Delgado A.
Published: March 2003

Here we deal with the influence of heat‐transport effects on a high‐pressure‐induced enzyme inactivation in packed substances. Special attention is given to the influence of the geometrical scale and to the heat‐transfer characteristics of the packaging material. The investigation is based on mathematical modeling and numerical simulation. The method accounts both for compression phase and holding phase. The model includes convective and conductive heat transfer, fluid motion as well as an enzyme transport equation with a first‐order kinetic source term accounting for the inactivation. Three configurations with a total volume of 0.8 L, 6.3 L, and 50.3 L are considered. The pressure medium is water. The enzyme solution isB. subtilisα‐amylase dissolved in a TRIS‐HCl‐buffer. The packaging material is polypropylene. The heat‐transfer coefficient for conduction through the packaging material is varied to simulate both changes in the material properties as well as modifications of the packaging material thickness. It is found that the efficiency of the inactivation increases with increasing chamber volume as long as the kinetic inactivation constant is increasing with temperature. In the considered case the activity retention obtained in a 0.8 L volume is about 2.4 times larger than the one obtained for the same process carried out in a 50.3 L volume. Furthermore, it was found that the properties of the packaging material could induce a significant degree of nonuniformity (worst case = 69%). An appropriate choice of the material can lead to maximum inactivation and maximum process uniformity since advantage is taken from the slow heat exchange after the compression phase. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 725–735, 2003.
Suggested improvements to the standard filter paper assay used to measure cellulase activity
Authors: Coward‐Kelly Guillermo , Aiello‐Mazzari Cateryna , Kim Sehoon , Granda Cesar , Holtzapple Mark
Published: March 2003

Two suggestions can be found in the literature to improve the reproducibility of the Mandels' filter paper assay: add supplemental cellobiase and increase the boiling time for color development. Here we provide data that strongly supports adding supplemental cellobiase. Adding supplemental cellobiase increased assay response by 56%. Cellulases from different sources have different cellobiase activities, which would cause significant variation in the assay response. There is no need for additional boiling time—5 minutes is sufficient. For maximum reproducibility, it is essential that the water bath vigorously boil so that temperature excursions are minimized. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 745–749, 2003.
Influence of morphology on the near‐infrared spectra of mycelial biomass and its implications in bioprocess monitoring
Authors: Vaidyanathan Seetharaman , White Stewart , Harvey Linda M. , McNeil Brian
Published: March 2003

Bioprocesses that employ mycelial microorganisms are commercially important. The application of optical techniques for the measurement of biomass in such processes is limited by the morphological heterogeneity exhibited by the mycelial microorganism employed. We investigated the influence of morphology on the near‐infrared (NIR) spectra of the biomass of Streptomyces fradiae, a filamentous microorganism, by studying the spectra of mycelial suspensions that were manipulated to generate a range of morphological forms. Computerized image analysis was used to characterize the morphological forms. Principal component analysis was used to assess the spectral variations and study correlations to the manipulated mycelial morphology. Although morphology was found to influence the near infrared transmittance spectra of biomass, the influence was less pronounced than in the visible region, the spectral information at longer wavelengths (1600–2350 nm) showing greater stability to morphological variations. Long‐wave NIR spectral information is therefore likely to be more useful in estimating biomass in mycelial bioprocesses. Furthermore, the NIR reflectance spectra of dried biomass were found to show correlations to the morphological variations introduced, suggesting that NIR spectra may be useful in obtaining morphology related information. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 715–724, 2003.
Supernumerary humeral heads of the biceps brachii muscle revisited
Authors: Rodríguez‐Niedenführ Marc , Vázquez Teresa , Choi David , Parkin Ian , Sañudo José R.
Published: March 2003

Supernumerary humeral heads of the biceps brachii muscle were found in 27 (15.4%) of 175 cadavers. They were bilateral in five cadavers and unilateral in 22 (8 left, 14 right), giving a total of 32 examples in 350 arms (9.1%). Depending on their origin and location, the supernumerary heads were classified as superior, infero‐medial, and infero‐lateral humeral heads. Previous studies were reviewed using this classification. The infero‐medial humeral head was observed in 31 of 350 (9%) arms and was therefore the most common variation. The superior humeral head was observed in five (1.5%). The infero‐lateral humeral head was the least common variation, observed only in one (0.3%) of 350 arms. A biceps brachii with three heads was observed in 27 of 350 (7.7%) arms and with four heads in five (1.4%) arms. Clin. Anat. 16:197–203, 2003. © 2003 Wiley‐Liss, Inc.
Force‐length characteristics of the in vivo human gastrocnemius muscle
Authors: Maganaris Constantinos N.
Published: March 2003

In this study, the force‐length characteristics of the in vivo medial (GM) and lateral (GL) heads of the human gastrocnemius muscle were estimated from measurements in eight healthy male subjects. This involved: 1) dynamometry‐based measurements of the moment generated during maximal isometric plantar flexion; 2) ultrasound‐based measurements of fascicular length and pennation angle; and 3) ultrasound‐based calculations of moment arm lengths. All measurements were taken over the ankle angle range from 20° of dorsiflexion to 30° of plantar flexion. Tendon forces were calculated by dividing the moments recorded by the muscle moment arm lengths, and fascicular forces were calculated by dividing the tendon forces estimated by the cosine of pennation angle. In the transition from 30° of plantar flexion to 20° of dorsiflexion, the GM muscle fascicular length and force increased linearly from 24 to 39 mm and from 222 to 931 N, respectively. Over the same ankle angle range, the GL muscle fascicular length and force increased linearly from 30 to 47 mm and from 139 to 393 N, respectively. Estimates of the sarcomeric lengths corresponding to the fascicular lengths measured indicated that the two muscles operated in the range 1.4–2.2 μm, below the optimal length region for force generation according to the cross‐bridge mechanism of contraction. These results indicate that the force–length relation of the in vivo human gastrocnemius muscle is limited to the ascending limb of the bell‐shaped force–length curve obtained from experiments on isolated material. Clin. Anat. 16:215–223, 2003. © 2003 Wiley‐Liss, Inc.
Anatomical study of the “trochanteric bursa”
Authors: Dunn Tirith , Heller C. Ann , McCarthy Stanley W. , Dos Remedios Cristobal
Published: March 2003

To resolve ambiguity in the literature about the anatomy of the “trochanteric bursa” or trochanteric subgluteus maximus bursa, this study examines the constancy, structure, and relationships of this bursa in a series of anatomical dissections of the hip. Sixteen embalmed hip specimens, from subjects aged 63–91 years, were examined. Subgluteus maximus bursae were demonstrated in 13 hips. In each of these a bursa, the deep bursa, was seen immediately superficial to the common attachment of the gluteus medius, minimus, and vastus lateralis muscles onto the greater trochanter. In five hips a smaller second bursa, the superficial bursa, was reflected with the gluteus maximus muscle. In two hips, four bursae were identified. The additional bursae were associated with either the deep or the superficial bursa. Examination of histological samples from the bursal walls confirmed the presence of a synovial lining in varying stages of development in seven of the eight bursae examined. Branches of the inferior gluteal nerve were seen to supply deep and superficial bursae in two dissections. The study data indicate that subgluteus maximus bursae at the level of the greater trochanter are an expected finding in the older age group and that they vary in number, position, and histological appearance. These features give rise to the hypothesis that these bursae are acquired as a consequence of excessive friction between the greater trochanter and the gluteus maximus as it inserts into the fascia lata. Clin. Anat. 16:233–240, 2003. © 2003 Wiley‐Liss, Inc.
How should we treat short hepatic veins and paracaval branches in anterior hepatectomy using the hanging maneuver without mobilization of the liver?
Authors: Hirai Ichiro , Murakami Gen , Kimura Wataru , Kanamura Tetsuhiro , Sato Iwao
Published: March 2003

This study investigates the relevant anatomy for applying the hanging maneuver to hepatectomy by an anterior approach, where liver mobilization is not possible. Using 176 cadaveric livers, we morphometrically investigated the distribution of venous openings within the retrohepatic portion of the inferior vena cava (IVC); next, we conducted a series of experiments to identify which course for insertion of a pair of forceps preserved the thickest of these veins. After anterior dissection of the liver, we carried out an anterior incision along a plane within an area free of venous openings in the IVC. The area free of venous openings was between the thickest caudate vein and the inferior right hepatic vein (IRHV), and averaged 16.2 mm in width. When forceps were inserted along the rightward course connecting the right inferior angle of the right lobe and the same pocket‐like space between the terminals of the middle and right hepatic veins, the caudate vein was very likely to be preserved, whereas the IRHV was not. In contrast, the leftward course connecting the gallbladder fossa and the pocket‐like space provided an almost opposite incidence of damage. The portal territory of the hilar bifurcation was most likely to be damaged during a virtual incision along an avascular plane; however, the caudate branch of left portal origin was rarely damaged. The rightward course may be the best method for forceps insertion in cases where there is no IRHV. To preserve the caudate vein and the IRHV, taping on the right side of the IRHV and retracting to the right, or changing the direction of the forceps from leftward to rightward when the tip of the forceps is anterior to the IVC is recommended. The hanging maneuver by an anterior approach without mobilization is convenient for right or left hepatectomy for large tumors or hardened liver. Clin. Anat. 16:224–232, 2003. © 2003 Wiley‐Liss, Inc.
Arterial supply of the soleus muscle: Anatomical study of fifty lower limbs
Authors: Raveendran S.S. , Kumaragama K.G.J.L.
Published: March 2003

Soft tissue defects of the lower limb are a formidable challenge to the plastic surgeon but a soleus muscle flap often provides the solution. Various types of soleus muscle flap have been described, based mainly on the vascular supply. The arterial blood supply of the soleus muscle was studied in 50 cadaveric lower limbs. The blood vessels and their branches to the muscle were dissected. The distance of the origin of the perforators was measured from fixed bony landmarks. Branches of the popliteal artery trunk, the posterior tibial artery, and the peroneal artery supplied the soleus muscle. The number of branches to the soleus muscle from these main arteries were analyzed. The medial part of the muscle was supplied throughout its length by perforators arising from the posterior tibial artery. This constant feature makes the medial part of the muscle reliable as a proximally or distally based flap. The average distances of the lower perforators arising from the posterior tibial artery were 6.5 cm, 11.6 cm, and 16.8 cm from the medial malleolus. The branches of the peroneal artery were mostly distributed in the upper half of the muscle. These large pedicles allow a composite transfer of the soleus muscle with the fibula. Lower perforators were demonstrated to arise from the peroneal artery in 60% of the limbs but the scarcity of perforators in this region limits the clinical usefulness of an inferiorly based lateral hemisoleus flap. The study demonstrates the distribution of arteries entering the soleus muscle and how the information may be used in the design of soleus muscle flaps. The average numbers of the perforators arising from the vessels and their distribution have been highlighted. Clin. Anat. 16:248–252, 2003. © 2003 Wiley‐Liss, Inc.
Discrimination of bilateral differences in the loci of tactile stimulation is impaired in subjects with Parkinson's disease
Authors: Zia Shagufta , Cody Frederick W.J. , O'Boyle Donald J.
Published: March 2003

We have compared the abilities of patients with idiopathic Parkinson's disease (PD), while on levodopa (L‐dopa), and control subjects to discriminate bilateral differences in the loci of tactile stimulation. On each trial, one of a subject's forearms served as the reference arm and the other as the test arm. The two forearms were supinated and placed side‐by‐side on a table‐top in front of the subject. Seven cutaneous test loci, 3 mm apart, were arrayed proximo‐distally on the flexor aspect of each forearm, with the fourth (central) serving as a reference point. On each trial, two punctate tactile stimuli (of intensity well above perceptual threshold) were applied simultaneously to 1) one of the seven test loci on the test forearm and 2) the reference (central) locus on the reference arm. Subjects, with eyes closed, stated which forearm (test or reference) was stimulated more distally. Estimates of the difference limen (DL, a measure of discriminatory threshold) and the point of subjective equality (PSE, the test locus perceived to correspond to the reference locus) were derived from psychophysical functions (ogives). For each subject, one arm was defined as ‘better’ and the other as ‘worse.’ Among PD patients, this definition was in terms of the relative severity of clinical motor signs (combined scores for bradykinesia, rigidity and tremor) of the two arms, whereas among controls it was according to relative DL magnitudes (sensory/perceptual performance). The mean DL of the patients significantly exceeded that of control subjects on both the ‘better’ and ‘worse’ arms as test side, but mean PSE values did not differ significantly between groups. Thus, our PD patients were impaired in discriminating bilateral differences in the locations of tactile stimulation, while perceiving normally the relative locations of the proximo‐distal centers of the two stimulus arrays. Clin. Anat. 16:241–247, 2003. © 2003 Wiley‐Liss, Inc.
Surgically relevant structure on the ascending aorta
Authors: Morrison J.J. , Codispoti M. , Campanella C.
Published: March 2003

We have examined the transverse vascularized ridge observed on the anterior surface of the intra‐pericardial aorta during cardiac surgery. The ridge was a consistent feature of 20 consecutive cardiac patients and 11 cadavers no more than 2 days post‐mortem. The aortic ridge was absent, however, in four of five embalmed cadavers additionally examined, probably due to the embalming process. Histological examination showed the ridge to be well vascularized, well innervated and composed of adipose tissue. This structure has surgical relevance as a possible source of post‐operative hemorrhage, sometimes necessitating re‐sternotomy. Clin. Anat. 16:253–255, 2003. © 2003 Wiley‐Liss, Inc.
Giant intracavernous internal carotid artery aneurysm with fatal epistaxis
Authors: Haffajee M.R. , Naidoo S.
Published: March 2003

The case history and autopsy findings of a 32‐year‐old male, who suffered a mild closed‐head injury and then had repeated epistaxis beginning 5 months later, is presented. The condition culminated in an episode of fatal epistaxis 1 year after the injury. At one time during the course of his work‐up, the etiology of his repeated epistaxis was thought to be a vascular nasopharyngeal neoplasm. The diagnosis of an intracavernous internal carotid artery aneurysm was made only at autopsy. The principles of management of traumatic intracavernous internal carotid artery aneurysm presenting with epistaxis are discussed. Clin. Anat. 16:277–281, 2003. © 2003 Wiley‐Liss, Inc.