bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel skeletogenic patterning roles for the olfactory pit
Authors: Szabo-Rogers Heather L. , Geetha-Loganathan Poongodi , Whiting Cheryl J. , Nimmagadda Suresh , Fu Katherine , Richman Joy M.
Published: December 2008

The position of the olfactory placodes suggests that these epithelial thickenings might provide morphogenetic information to the adjacent facial mesenchyme. To test this, we performed in ovo manipulations of the nasal placode in the avian embryo. Extirpation of placodal epithelium or placement of barriers on the lateral side of the placode revealed that the main influence is on the lateral nasal, not the frontonasal, mesenchyme. These early effects were consistent with the subsequent deletion of lateral nasal skeletal derivatives. We then showed in rescue experiments that FGFs are required for nasal capsule morphogenesis. The instructive capacity of the nasal pit epithelium was tested in a series of grafts to the face and trunk. Here, we showed for the first time that nasal pits are capable of inducing bone, cartilage and ectopic PAX7 expression, but these effects were only observed in the facial grafts. Facial mesenchyme also supported the initial projection of the olfactory nerve and differentiation of the olfactory epithelium. Thus, the nasal placode has two roles: as a signaling center for the lateral nasal skeleton and as a source of olfactory neurons and sensory epithelium.
A qualitative exploration of quality of life among individuals diagnosed with an acoustic neuroma
Authors: Brooker Joanne , Burney Sue , Fletcher Jane , Dally Michael
Published: December 2008

Objectives. To explore quality of life outcomes and the factors that influenced adjustment among individuals diagnosed with an acoustic neuroma.

Design. This qualitative study involved a focus group design.

Methods. Twenty‐one participants who had been diagnosed with and/or treated for an acoustic neuroma since 2000 attended one of four focus groups. Transcripts of the focus group discussions underwent thematic analysis to explore and describe the quality of life of participants and factors that impacted on their adjustment to the condition.

Results. Important themes that emerged were ‘physical symptoms’, ‘psychological wellbeing’, ‘social wellbeing’, ‘functional status’, and ‘psychosocial factors that influenced adjustment’. Factors that influenced adjustment included severity of physical symptoms, co‐morbid conditions, optimism, control, social comparison, and social support.

Conclusions. Participants conveyed a diverse range of experiences in relation to quality of life. In addition to severity of physical symptoms, psychosocial factors also emerged as important influences on quality of life.
The Problems with Publishing: Obstacles Faced by History Consultants in Publishing Their Work
Authors: Godfrey Matthew C.
Published: December 2008

This paper discusses some of the issues that consultants face when trying to publish products that they have produced as part of their business. It examines four main topics: the purpose behind the creation of the work product and its scope, the collaborative nature of public history writing, bureaucratic red-tape related to publishing, and the relative lack of emphasis on publishing in the consulting world. In addition, the paper discusses proper forums for the publication of public history.
Association of Smoking in Adolescence With Abdominal Obesity in Adulthood: A Follow-Up Study of 5 Birth Cohorts of Finnish Twins
Authors: Saarni Suoma E. , Pietiläinen Kirsi , Kantonen Suvi , Rissanen Aila , Kaprio Jaakko
Published: December 2008

Objectives. We studied the association of adolescent smoking with overweight and abdominal obesity in adulthood.

Methods. We used the FinnTwin16, a prospective, population-based questionnaire study of 5 consecutive and complete birth cohorts of Finnish twins born between 1975 and 1979 (N = 4296) and studied at four points between the ages of 16 and 27 years to analyze the effect of adolescent smoking on abdominal obesity and overweight in early adulthood.

Results. Smoking at least 10 cigarettes daily when aged 16 to 18 years increased the risk of adult abdominal obesity (odds ratio [OR]=1.77; 95% confidence interval [CI] = 1.39, 2.26). After we adjusted for confounders, the OR was 1.44 (95% CI = 1.11, 1.88), and after further adjustment for current body mass index (BMI), the OR was 1.34 (95% CI = 0.95, 1.88). Adolescent smoking significantly increased the risk of becoming overweight among women even after adjustment for possible confounders, including baseline BMI (OR = 1.74; 95% CI = 1.06, 2.88).

Conclusions. Smoking is a risk factor for abdominal obesity among both genders and for overweight in women. The prevention of smoking during adolescence may play an important role in promoting healthy weight and in decreasing the morbidity related to abdominal obesity.
Improving 24-Month Abstinence and Employment Outcomes for Substance-Dependent Women Receiving Temporary Assistance for Needy Families With Intensive Case Management
Authors: Morgenstern Jon , Neighbors Charles J. , Kuerbis Alexis , Riordan Annette , Blanchard Kimberly A. , McVeigh Katharine H. , Morgan Thomas J. , McCrady Barbara
Published: December 2008

Objective. We examined abstinence rates among substance-dependent women receiving Temporary Assistance for Needy Families (TANF) in intensive case management (ICM) over 24 months and whether ICM yielded significantly better employment outcomes compared with a screen-and-refer program (i.e., usual care).

Methods. Substance-dependent (n = 302) and non–substance dependent (n = 150) TANF applicants in Essex County, New Jersey, were recruited. We randomly assigned substance-dependent women to ICM or usual care. We interviewed all women at 3, 9, 15, and 24 months.

Results. Abstinence rates were higher for the ICM group than for the usual care group through 24 months of follow-up (odds ratio [OR] = 2.11; 95% confidence interval [CI] = 1.36, 3.29). A statistically significant interaction between time and group on number of days employed indicated that the rate of improvement over time in employment was greater for the ICM group than for the usual care group (incidence rate ratio = 1.03; 95% CI = 1.02, 1.04). Additionally, there were greater odds of being employed full time for those in the ICM group (OR = 1.68; 95% CI = 1.12, 2.51).

Conclusions. ICM is a promising intervention for managing substance dependence among women receiving TANF and for improving employment rates among this vulnerable population.
Types and processes of slope movements along East-West Highway, Surai Khola area, Mid-Western Nepal Sub-Himalaya
Authors: Tamrakar Naresh Kazi , Yokota Shuichiro
Published: December 2008

Many landslides and debris flows have occurred and destroyed the East-West Highway that extends along the valley slopes of the Siwalik Hills. Wedge slide, rock fall, slump, rock topple-rock slide, debris flow, slope failures and gully erosion were recorded in the Surai Khola area. The most of the slope movements distributed therein are active, reactivated and retrogressive. Differential weathering and gully erosion related to bedding planes of rocks are common phenomena, which contribute instability. The areas between Surai Naka and the Chor Khola suffer remarkable uplift, tilting and river incision, and thus indicate tectonically active zone. Tectonic activity, lithological assemblage, rock strength and weathering of the Siwalik Group have remarkable input on distribution, causes and activity of slope movements.   doi: 10.3126/bdg.v11i0.1427        Bulletin of the Department of Geology, Tribhuvan University, Kathmandu, Nepal, Vol. 11, 2008, pp. 1-4
Petrographic records of two metamorphic events in the Lesser Himalayan metabasites, Modi Khola section, central Nepal
Authors: Paudel Lalu
Published: December 2008

Metabasites of the Lesser Himalaya along the Modi Khola valley in central Nepal are the supracrustal dikes and sills of basic igneous rocks emplaced in the clastic sediments and later metamorphosed together with the host rocks. They contain almost a constant metamorphic mineral assemblage of Ca-amphiboles+plagioclase+biotite+quartz±epidote±chlorite+(Fe-Ti oxides). Amphiboles occur in the form of porphyroblast and recrystallized matrix. The porphyroblasts are zoned with actinolitic cores and hornblende rims. The recrystallized matrix ranges in composition from actinolite in chlorite zone to hornblende in biotite and garnet zones. The cores of porphyroblasts are pre-kinematic and were probably formed prior to the Tertiary Himalayan orogeny. The rims of porphyroblasts and matrix amphiboles are syn-kynematic and were formed during the Upper Main Central Thrust activity in the Tertiary. The systematic changes in amphibole compositions as well as textural characteristics of metabasites are in good agreement with the classical concept of increasing metamorphic grade and intensity of deformation structurally upwards towards the Upper Main Central Thrust in the Lesser Himalaya.           doi: 10.3126/bdg.v11i0.1428 Bulletin of the Department of Geology, Tribhuvan University, Kathmandu, Nepal, Vol. 11, 2008, pp. 5-12
Groundwater condition of Banepa area, Central Nepal
Authors: Shrestha Suresh , Shrestha Suresh Das
Published: December 2008

Only surface water has been distributed in the Banepa Municipality area, Central Nepal by Nepal Water Supply Corporation (NWSC) and is not sufficient as per the demand of public. A hydrogeological study was made to know the groundwater potential of the area. Banepa lies entirely in the Lesser Himalaya and constitutes consolidated phyllite and metasandstone basement rocks, and Quaternary sediment of gravel, sand and carbonaceous clay deposited in the valley. The thickness of sediment ranges from 20 to 40 m, of which gravel, sand and clay individually approach upto 20, 5 and 15 m, respectively. Transmissivity of the aquifer varies from 0.8 to 3.15 m2/day. Hydraulic conductivity varies from 0.022 to 0.14 m/day and specific capacity varies from 1.2 to 72 m3/day/m in the study area. The thickness of the aquifer is low and the hydraulic properties are also not favorable to extract sufficient quantity of groundwater in Banepa area. Therefore, an alternative source of water supply should be explored to fulfill present and future water demand.   doi: 10.3126/bdg.v11i0.1540 Bulletin of the Department of Geology, Tribhuvan University, Kathmandu, Nepal, Vol. 11, 2008, pp. 31-40
Process of cement production in Nepal
Authors: Pandey Paresh Raj , Banskota Narayan
Published: December 2008

This paper describes general process of cement production from exploration of limestone deposit to production of clinker and finally cement. Exploration of limestone comprises area selection, target definition, reserve calculation, resource evaluation and reserve definition. After exploration, mining is taken up. Quarried limestone is stockpiled and then is blended with other raw material like clay/shale, silica, iron ore in required proportion. The blended material is then heated at high temperature upto 1400-1450°C in a kiln to produce clinker. The clinker is grinned along with 3-5% gypsum to produce cement.   doi: 10.3126/bdg.v11i0.1545 Bulletin of the Department of Geology, Tribhuvan University, Kathmandu, Nepal, Vol. 11, 2008, pp. 71-78
Closure of large skull base defects after endoscopic transnasal craniotomy
Authors: Harvey Richard J. , Nogueira João F. , Schlosser Rodney J. , Patel Sunil J. , Vellutini Eduardo , Stamm Aldo C.
Published: December 2008

Object

The authors describe the utility of and outcomes after endoscopic transnasal craniotomy and skull reconstruction in the management of skull base pathologies.

Methods

The authors conducted a observational study of patients undergoing totally endoscopic, transnasal, transdural surgery. The patients included in the study underwent treatment over a 12-month period at 2 tertiary medical centers. The pathological entity, region of the ventral skull base resected, and size of the dural defect were recorded. Approach-related complications were documented, as well as CSF leaks, infections, bleeding-related complications, and any minor complications.

Results

Thirty consecutive patients were assessed during the study period. The patients had a mean age of 45.5 ± 20.2 years and a mean follow-up period of 182.4 ± 97.5 days. The dural defects reconstructed were as large as 5.5 cm (mean 2.49 ± 1.36 cm). One patient (3.3%) had a CSF leak that was managed endoscopically. Two patients had epistaxis that required further care, but there were no complications related to intracranial infections or bleeding. Some minor sinonasal complications occurred.

Conclusions

Skull base endoscopic reconstructive techniques have significantly advanced in the past decade. The use of pedicled mucosal flaps in the reconstruction of large dural defects resulting from an endoscopic transnasal craniotomy permits a robust repair. The CSF leak rate in this study is comparable to that achieved in open approaches. The ability to manage the skull base defects successfully with this approach greatly increases the utility of transnasal endoscopic surgery.
Vesicles for Signal Amplification in a Biosensor for the Detection of Low Antigen Concentrations
Authors: Grieshaber Dorothee , De Lange Victoria , Hirt Thomas , Lu Zhihua , Vörös Janos
Published: December 2008

The sensitivity of biosensors is often not sufficient to detect diagnostically relevant biomarker concentrations. In this paper we have utilized a Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) to detect dissipative losses induced by the attachment of intact vesicles. We modified a sandwich assay by coupling the secondary antibodies to vesicles. This resulted in an increase of detection sensitivity, achieving a diagnostically relevant detection limit of 5 ng/ml or 30 pM antigens. In addition, we could combine the individual assay steps to decrease the total time to result in about 30 minutes.
PREDICTING URBAN LAND PRICES: A COMPARISON OF FOUR APPROACHES
Authors: Hannonen Marko
Published: December 2008

This paper investigates forecasting accuracy of four different hedonic approaches, when vacant urban land prices are predicted in local markets. The investigated hedonic approaches are: 1) ordinary least squares estimation, 2) robust MM‐estimation, 3) structural time series estimation and 4) robust local regression. Post‐sample predictive testing indicated that more accurate predictions are obtained if the unorthodox methods of this paper are used instead of the conventional least squares estimation. In particular, the predictive unbiassness can significantly be improved when using the unconventional hedonic methods of the study. The paper also studied the structure of urban land prices. The most important attribute variables in explaining land prices were permitted building volume, house price index, northing and easting. The influence of parcel size variable and different indicator variables on land prices were much weaker. Santrauka Nagrinėjama, kokiu tikslumu keturi skirtingi hedonistiniai metodai prognozuoja laisvų žemės plotų kainas vietinėse miestų rinkose. Nagrinėti tokie hedonistiniai metodai: 1) mažiausiųjų kvadratų metodas, 2) daugybinių modelių vertinimas, 3) struktūrinių laiko eilučių vertinimas, 4) lokalinė regresinė analizė. Post-sample prognostinis testas parodė, kad tikslesnės prognozės gaunamos taikant netradicinius šiame darbe nurodytus metodus, o ne įprastą mažiausiųjų kvadratų metodą. Taikant netradicinius hedonistinius tyrimo metodus, gali gerokai padidėti prognozių nešališkumas. Darbe nagrinėta ir žemės kainų mieste struktūra. Aiškinant žemės kainas iš būdingų kintamųjų svarbiausi buvo leidžiamas pastato dydis, būsto kainų indeksas, sklypo padėtis. Sklypo dydžio kintamasis ir įvairių rodiklių kintamieji žemės kainoms turėjo daug mažesnę įtaką.
Association of Fcγ Receptor Polymorphisms with Adult Onset Still’s Disease in Korea
Authors: WOO JIN-HYUN , SUNG YOON-KYOUNG , LEE JIN-SOOK , CHUNG WON TAE , CHOE JUNG-YOON , SONG GWAN GYU , YOO DAE-HYUN
Published: December 2008

Objective.

Fcγreceptors (FcγR) have important functions in the regulation of immune response and clearance of immune complex. High levels of immunoglobulins have been observed in patients with the active stage of adult onset Still’s disease (AOSD), and high-dose intravenous immunoglobulin treatment has decreased the disease activity of AOSD. We investigated polymorphisms of FcγR as genetic factors influencing susceptibility or disease course of AOSD in Korea.

Methods.

We genotyped the FcγRIIA H/R131, IIIA F/V176, and IIIB NA1/NA2 loci in 98 patients with AOSD and 151 healthy controls. Genotyping was performed using sequence-specific PCR. Patients with AOSD were subdivided into groups according to disease course: monocyclic systemic, polycyclic systemic, or chronic articular type. Allelic, genotypic, and haplotypic associations were analyzed by chi-square test.

Results.

No significant skewing in any of the 3 FcγR polymorphisms was found between Korean AOSD patients and controls. FcγRIIA R/R131 and R/H131 genotype in patients with chronic articular-type disease was more frequent than in controls (p = 0.006 and pcorr = 0.018). No differences of genotypic and allelic frequencies were found between other disease course types and controls. Haplotype IIA R131-IIIA F176-IIIB NA2 was more frequent in AOSD patients than in controls (p = 0.021).

Conclusion.

Although FcγR polymorphisms are not associated with development of AOSD in Koreans, the haplotype IIA R131-IIIA F176-IIIB NA2 may be associated with AOSD. Also, the FcγRIIA polymorphism may be associated with chronic articular-type AOSD. We need to identify whether these polymorphisms are associated with a response to anti-tumor necrosis factor agents in patients with AOSD.
Association of Interleukin 23 Receptor Variants with Psoriatic Arthritis
Authors: RAHMAN PROTON , INMAN ROBERT D. , MAKSYMOWYCH WALTER P. , REEVE JEFF P. , PEDDLE LYNETTE , GLADMAN DAFNA D.
Published: December 2008

Objective.

A recent genome-wide pooling study noted a significant association of interleukin 23 receptor (IL-23R) and psoriasis. Overxpression of IL-23 has been detected in lesional psoriatic skin, and induces epidermal proliferation. Given the interplay between psoriasis and PsA, we examined the association of IL-23R variants in 2 independent Canadian Caucasian cohorts of patients with psoriatic arthritis (PsA).

Methods.

We examined 496 PsA probands and 476 controls. Cases and controls were genotyped for a panel of 11 single-nucleotide polymorphisms (SNP) in IL-23R. Allele and haplotype associations were calculated using WHAP software. P values for haplotype associations were calculated using a permutation test.

Results.

The 381Gln allele of the coding SNP Arg381Gln (rs11209026) was found to be protective in the Canadian population (p = 0.004; corrected p = 0.044).A 2-marker haplotype from SNP rs7530511 and rs11209026 was associated with PsA (p = 0.011). All 3-marker sliding windows containing SNP rs11209026 were associated with PsA (p = 0.02 for all 3 windows). The magnitude of effect of IL-23R association in PsA appears to be similar to that reported in uncomplicated psoriasis.

Conclusion.

Significant associations between Arg381Gln SNP and haplotypes encoding this variant were noted in PsA. It remains to be determined what contribution of this association, if any, is specifically due to the inflammatory arthritis (PsA) rather than psoriasis.
A composite reaction engineering approach to drying of aqueous droplets containing sucrose, maltodextrin (DE6) and their mixtures
Authors: Patel Kamlesh C. , Chen Xiao Dong , Lin Sean X. Q. , Adhikari Benu
Published: December 2008

Recently, several studies have been published on the spray drying of sucrose and other low‐molecular‐weight sugars which are typically sticky materials. Sticky materials can not be processed under normal drying conditions and may require addition of high‐molecular‐weight carbohydrates such as maltodextrin. Predicting appropriate drying conditions are however difficult due to the unavailability of drying kinetics. In this article, we have formulated the drying kinetics model using the reaction engineering approach (REA) for the drying of aqueous sucrose and aqueous maltodextrin (DE6) droplets. The relative activation energy was empirically obtained based on experimental measurements. To model the drying of droplets containing both solutes (sucrose and maltodextrin), a new “composite” REA has been established and presented here for the first time. Results demonstrated that the composite REA forms a reliable framework to model the drying of aqueous solutions of pure carbohydrates and their mixtures. © 2008 American Institute of Chemical Engineers AIChE J, 2009
Nonisothermal crystallization behaviors of silk‐fibroin‐fiber‐reinforced poly(ϵ‐caprolactone) biocomposites
Authors: Qiao Xiuying , Li Wei , Sun Kang , Xu Shi , Chen Xiaodong
Published: December 2008

With differential scanning calorimetry measurements, the nonisothermal crystallization of biocomposites of poly(ϵ‐caprolactone) (PCL) reinforced with silk fibroin fiber (SF) was investigated. With the gradual addition of SF, the strengthening of the heterogeneous nucleation reagent effect of SF led to the acceleration of PCL crystallization, and secondary crystallization occurred and became more remarkable with increases in the cooling rate and SF content. Moreover, with the introduction of SF and an increase in the cooling rate, the nucleation and growth mode of the PCL crystalline phase was slightly changed. Because of the confinement of the fiber network structure, the crystallite size of PCL was reduced, the crystallization exothermicity of PCL decreased, and the crystallization activation energy of PCL increased. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Poly(vinyl pyrrolidone‐co‐octavinyl polyhedral oligomeric silsesquioxane) hybrid nanocomposites: Preparation, thermal properties, and Tg improvement mechanism
Authors: Yang Benhong , Li Jirong , Wang Jiafeng , Xu Hongyao , Guang Shangyi , Li Cun
Published: December 2008

A series of poly(vinyl pyrrolidone‐co‐octavinyl polyhedral oligomeric silsesquioxanes) (PVP‐POSS) organic–inorganic hybrid nanocomposites containing different percentages of POSS were prepared via free radical polymerization and characterized by FTIR, high‐resolution 1H‐NMR, solid‐state 29Si‐NMR, GPC, DSC, and TGA. POSS contents in these nanocomposites can be effectively controlled by varying the POSS feed ratios which can be accurately quantified by FTIR curve calibration. On the basis of 29Si‐NMR spectra, average numbers of reacted vinyl groups of each octavinyl‐POSS macromer are calculated to be 5–7, which depends on POSS feed ratios. Both GPC and DSC results indicate that these nanocomposites display network structure and the degree of crosslinking increases with the increase of the POSS content. The incorporation of POSS into PVP significantly improves their thermal properties (Tg and Tdec) primarily due to crosslinking structure and dipole–dipole interaction between POSS cores and PVP carbonyl groups. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Surface characterization of hydrophilic coating obtained by low‐pressure CH4O2 plasma treatment on a polypropylene film
Authors: López R. , Sanchis R. , García D. , Fenollar O. , Balart R.
Published: December 2008

The use of surface treatments at industrial level is generalized as they allow obtaining a wide variety of properties such as soft in the touch, hydrophilic behavior, and biocompatibility. The use of low‐pressure plasma techniques with organic gases or organic mixtures is an easy way to obtain surface coatings very small in depth through plasma‐polymerization processes that can be assimilated to a plasma‐enhanced chemical vapor deposition (PECVD) process. In this work, we have carried out a plasma‐polymerization process on a polypropylene (PP) film to obtain a hydrophilic coating. To obtain this, the film surface has been treated on a low‐pressure plasma reactor with a methane–oxygen mixture gas with a volume ratio of 80 : 20, respectively. The chemistry changes in the outermost layers of the deposited coating have been investigated with X‐ray photoelectron spectroscopy (XPS). The different processes that take part as a consequence of the interaction between the plasma gas species and the PP film surface mainly drive to the deposition of an organic layer, which is functionalized with oxygen‐based species as XPS study reveals. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Isothermal crystallization kinetics of high‐flow nylon 6 by differential scanning calorimetry
Authors: Zhang Fan , Zhou Li , Xiong Yuanqin , Liu Guangpeng , Xu Weijian
Published: December 2008

The isothermal crystallization kinetics have been investigated with differential scanning calorimetry for high‐flow nylon 6, which was prepared with the mother salt of polyamidoamine dendrimers and p‐phthalic acid, an end‐capping agent, and ε‐caprolactam by in situ polymerization. The Avrami equation has been adopted to study the crystallization kinetics. In comparison with pure nylon 6, the high‐flow nylon 6 has a lower crystallization rate, which varies with the generation and content of polyamidoamine units in the nylon 6 matrix. The traditional analysis indicates that the values of the Avrami parameters calculated from the half‐time of crystallization might be more in agreement with the actual crystallization mechanism than the parameters determined from the Avrami plots. The Avrami exponents of the high‐flow nylon 6 range from 2.1 to 2.4, and this means that the crystallization of the high‐flow nylon 6 is a two‐dimensional growth process. The activation energies of the high‐flow nylon 6, which were determined by the Arrhenius method, range from −293 to −382 kJ/mol. The activation energies decrease with the increase in the generation of polyamidoamine units but increase with the increase in the content of polyamidoamine units in the nylon 6 matrix. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Unsteady Cell Distributions in Capillary Networks
Authors: Furman M. B. , Olbricht W. L.
Published: December 2008

A numerical simulation is used to study the distribution and flux of red blood cells in capillary networks. The relationship between the motion of an individual cell in a single capillary and the overall transport of cells throughout a network is investigated.

Interpretation of results is greatly facilitated by the use of a computer graphics representation of the simulation. Steady‐state and certain time‐dependent cell distribution problems are studied, with a special focus on the sensitivity of the results to the presence of a small number of white cells.
Background Studies in the Modeling of Extrusion Cooking Processes for Soy Flour Doughs
Authors: Luxenburg L. A. , Baird D. G. , Joseph E. G.
Published: December 2008

Soy flour is processed in single screw extruders to yield textured vegetable protein used as meat extenders and replacements. The fundamental processes which take place in extrusion cooking of soy doughs are poorly understood from an engineering point of view. This paper is concerned with gaining an understanding of extrusion cooking in order to develop a quantitative model of this process in single screw extruders. Rheological and thermodynamic data are obtained over a range of conditions found in the extrusion process and this data is used both in understanding and modeling the extrusion cooking process.

In particular, differential scanning calorimetry (DSC) has been used to determine changes in the enthalpy of soy doughs at various moisture levels. It is observed that in general the enthalpy changes are small (e.g. of the order of 1.0 cal/g) and endothermic. However, if the dough is subjected to shear and thermal history, then the enthalpy changes become significant. The viscosity of the dough exhibits a mild increase in the temperature range where the endotherms are observed in the DSC data. Based on the results of this study, it is concluded that cooking does not involve cross‐linking of the proteins but more likely a conformation change of the molecules. Also, it is found that for the 40% to 60% added moisture soy flour dough systems, the rheological properties can be modeled using a Bingham model modified with a shear rate dependent viscosity.
Rate of Precipitation of Calcium Phosphate On Heated Surfaces
Authors: Barton Kathleen P. , Chapman Thomas W. , Lund Daryl
Published: December 2008

Fouling of a heated stainless steel surface by calcium phosphate precipitation has been studied in an annular flow apparatus, instrumented to provide a constant heat flux while measuring local metal‐surface temperatures. Models of the heat and mass‐transfer boundary layers are used to estimate interfacial temperatures and concentrations, from which the heterogeneous reaction rate is inferred. The analysis indicates that the reaction rate is a function of both chemical kinetics and mass transfer limitations.
Kinetics of Gel Forming in Enzyme Coagulated Milk
Authors: Carlson Alfred
Published: December 2008

A semi‐empirical kinetic model has been developed to explain the observed kinetics of gel formation in enzyme coagulated milk. The kinetic model assumes that the actual system can be represented by a two‐step reaction in series model in which both reactions are first order.

The initial reaction is the formation of potential cross‐link points corresponding to the hydrolysis of K‐casein which covers the surface of casein micelles. The second reaction is the formation of cross‐links between casein micelles as individual micelles interact with each other. The initial reaction is dependent on the concentration of enzyme in the solution, while the second reaction is enzyme independent. The formation of increasing numbers of cross‐links results in an increase in the shear modulus of the gel. The model correctly predicts the general shape of the shear modulus vs. time curve, and faithfully accounts for the influence of enzyme concentration of the rate of shear modulus increase. It is also consistent with the influence of pH and temperature, and denaturation on the activity of the enzyme for the range of these values tested.
Small‐Angle Neutron Scattering Studies of Protein‐Reversed Micelle Complexes
Authors: Sheu E. , Göklen K. E. , Hatton T. A. , Chen S.‐H.
Published: December 2008

Enzymes solubilized in organic solvents, hosted within the polar cores of surfactant aggregates, known as reversed micelles, provide many unique opportunities for new biocatalytic synthesis and protein separation processes. Small‐angle neutron scattering (SANS) studies have shown that insertion of the protein cytochrome‐c in the reversed micelle polar core causes a significant reapportioning of the surfactants and water between the filled and unfilled micelles, leading to an increase in overall size of the filled micelles relative to their empty counterparts. The simple shell and core model assuming single occupancy of the reversed micelles has significant limitations in interpreting data for high protein loadings, and points to the need for more detailed characterization of the protein‐reversed micelle interactions.
Selective Removal of H2S from Biogas by a Packed Silica Gel Adsorber Tower
Authors: Chou Tse‐Chuan , Lin Thong Yueh , Hwang Bing Joe , Wang Chung Cheng
Published: December 2008

The removal of hydrogen sulfide from biogas by silica gel was systematically studied. The results indicate that H2S could be selectively and completely removed from the biogas until the silica gel became saturated. When it became saturated, the color of silica gel changed from blue to black. The used silica gel could easily be regenerated and reused. The factors that affected the purification of biogas by silica gel were found to be the flow rate of biogas, the regeneration temperature, the degree of saturation of the silica gel, and the water content of silica gel. A mathematical model describing the operation of the adsorber was developed. The breakthrough curves and mass transfer coefficients of H2S were also obtained.
A Theoretical Examination of Adsorption Processes in Preparative Liquid Chromatography of Proteins
Authors: Regnier Fred E. , Mazsaroff István
Published: December 2008

This article examines retention in preparative chromatography in terms of the stoichiometric displacement model. This model is based on an equilibrium in which proteins and small displacing agents compete for ligands on the surface of chromatographic sorbents. Both the equilibrium constant for this process and the three‐dimensional structure of the macromolecule being separated are shown to be major determinants of retention in the analytical (linear) mode.

A theoretical application of this model to preparative (nonlinear) separations shows a high probability that there will be perturbations of the chromatographic distribution coefficient. The activity coefficients of proteins, molecular orientation of proteins toward the sorbent surface, and adsorption kinetics are both load and sample dependent. In addition, displacement effects by other macromolecular species are predicted at high proteins concentrations. This theoretical analysis concludes that mathematical modeling of the retention process under nonlinear conditions will be more sample specific and require significantly more data on column operating conditions, interfering sample components, sample load, and the chemical nature of the stationary phase.
Electrophoretic Elution from Monoclonal Antibody Immunoadsorbents: A Theoretical and Experimental Investigation of Controlling Parameters
Authors: Olson William C. , Yarmush Martin L.
Published: December 2008

An experimental and theoretical investigation of the mechanism of electrophoretic elution is described. The rate of elution of bovine serum albumin from monoclonal antibody immunoadsorbents was observed to increase with increasing electric field, increasing fractional saturation, and decreasing height of the immunoadsorbent column. Slower elution rates were observed from immunoadsorbents possessing higher affinities and capacities. A reaction‐migration mechanism is proposed in which the packed bed is modeled as a continuous hydrogel and in which the electrical field causes antigen that has spontaneously dissociated to migrate through the column under conditions of bound‐free equilibrium. Good qualitative and quantitative agreement is obtained between experiment and the predictions of a numerical model. A membrane device suitable for large‐scale application of this technique is discussed.
Techniques for Estimating the Vapor‐Liquid Equilibrium of Sugar Solutions
Authors: Leschke Rudolph J.
Published: December 2008

A number of options for the mathematical prediction of sugar solution boiling points and corresponding equilibrium pressures and concentrations have been examined. Existing methods for this purpose have been found inadequate in that they can predict equilibrium conditions accurately only over a small concentration range, and usually only for pure sucrose solutions. Simple statistical techniques either fit such data poorly, or result in equations that are unreliable when extended beyond the concentrations or pressures over which the data were fit. In this work, general thermodynamically consistent equations have been applied to the prediction of boiling points of pure sucrose solutions, corn syrup, or mixtures of the two; valid over the entire concentration range of soluble solids, and at varying pressures.
Polymer Dosage Considerations in Polyelectrolyte Precipitation of Protein
Authors: Clark K. M. , Glatz C. E.
Published: December 2008

The properties of aggregates formed by the precipitation of egg white proteins by carboxymethyl cellulose (CMC) were examined. Both the final level and the number of incremental additions of the polyelectrolyte were varied. The protein and lysozyme recoveries, particle zeta potential, and protein composition of the precipitate were found to vary with only the final CMC level. Particle size and size distributions were dependent on both the polymer dosage and manner of addition. Overdosed systems, or systems in which the CMC dosage exceeded that required for optimal total protein removal, produced the smallest particles, with size increasing as the number of incremental polymer additions increased. Optimally dosed systems produced the largest particles.
Improving the Acetone‐Butanol Fermentation Process With Liquid‐Liquid Extraction
Authors: Dadgar Ali M. , Foutch Gary L.
Published: December 2008

The design of Marlatt and Datta [1] was used to compare the design and economics for acetone‐butanol‐ethanol facilities. The process and economics include liquid‐liquid extraction and the required downstream modifications.
Bioconversion of D‐Xylose and Pretreated Oak Sawdust to Ethanol Using Clostridium Thermosacchrolyticum by Batch and Continuous Up‐Flow Reactors
Authors: Liu Hwai‐Shen , Hsu Hsien‐Wen , Sayler Gary S.
Published: December 2008

Bioconversions of lignocellulosic biomass, in particular sawdusts, into ethanol were investigated, first, acid hydrolyses by dilute sulfuric acids using 0.5, 1.0, and 2.0 weight percent were performed. The optimum hydrolysis condition was found to be 1% acid at 124°C and hydrolysis time 50 min. The total yields of sacchrification, primarily xylose, is 23.7 g which is obtained from 100 grams of sawdusts with a liter of dilute at the optimum condition.

Second, fermentations of xylose into ethanol were investigated using Clostridium thermosacchrolyticum (ATCC 31925) by a batch reactor and by a continuous up‐flow cylindrical reactor. In a continuous up‐flow reactor, two modes of operation are studied; namely, cells immobilized on polystyrene chips (size 2.79 × 3.78 × 2.64 mm) and cells freely suspended in the flowing substrate stream. The flow rates investigated were 17.5, 29.5, and 51.2 ml/hr for immobilized case and 27.3, 42.2, 66.1, and 109 ml/hr for free suspension case. The maximum concentration of ethanol yield obtained from the initial concentration of 6 g/l xylose was 1.8 g/l by a batch reactor, which is equivalent 60% of the theoretical conversion of xylose by weight. If the dilution rate is less than 0.3 hr−1, the concentration of ethanol by the continuous up‐flow reactor for both cases approach the maximum of that by a batch reactor.

Modellings of bioconversion kinetic parameters in Monod and Luedeking‐Piret formulas were also obtained. The specific growth rate for the microorganism in CM‐4 medium is found to be 0.43 hr−1.
Chitosan‐Alginate Complex Coacervate Capsules: Effects of Calcium Chloride, Plasticizers, and Polyelectrolytes on Mechanical Stability
Authors: Daly Mary M. , Knorr Dietrich
Published: December 2008

A method has been developed to form capsules with liquid cores where permeability can be modified without sacrificing membrane strength. The capsule is formed by dropwise addition of a 3% chitosan (polycation) solution into a 0.75% alignate (polyanion) solution. The resultant capsule consists of a liquid chitosan core with a hard alginate coating. The addition of CaCl2 to chitosan and glucose to alginate increased capsule strength. The membranes formed were strong enough to require up to 100 Newton during uniaxial compression to burst a 6.4 mm diameter capsule.
Shear Stress Effects on Human T Cell Function
Authors: Chittur K. K. , Mcintire L. V. , Rich R. R.
Published: December 2008

A modified Couette viscometer was used to study the effect of shear stresses on human T lymphocyte functions. Cell suspensions containing T cells, B cells, and monocytes were subjected to uniform shear stresses of 100 and 200 dynes/cm2 for 10 minutes. After stress exposure, the T cell response to the lectin phytohemagglutinin‐P (PHA‐P) was a strong function of the total cell concentration in culture. Stressed cells cultured with 0.5 μg/ml PHA‐P at an initial concentration of 1 × 106 cells/ml did not incorporate significant amounts of tritium‐labelled thymidine into their DNA. This inability to incorporate thymidine could be related to insignificant amounts of interleukin‐2 (IL2) detected in cell culture supernatants. A size analysis revealed that exposure to stress interfered with the ability of PHA‐P to induce cellular enlargement characteristic of an activation response. Fluorescence flow cytometric studies showed that the membrane depolarization response of cell suspensions to PHA‐P was significantly affected after exposure to shear stresses. In contrast, when shear stressed cells were cultured at lower cell densities of 0.5 × 106 and 0.25 × 106 cells/ml, the functional responses to PHA‐P were similar to those of controls. The data obtained suggest that controlled exposure to sublytic shear stresses results in alterations that can affect the proliferative response of the T cell population, and that these alterations are cell‐density dependent.
Integrated Reaction and Product Recovery in Bioreactor Systems
Authors: Daugulis Andrew J.
Published: December 2008

This review outlines the rationale used for selecting various approaches to integrating reaction and recovery, and how some approaches may be improved by further development.
Large‐Scale Purification of Tissue‐Type Plasminogen Activator from Cultured Human Cells
Authors: Harakas Nikos K. , Schaumann Jon P. , Connolly Daniel T. , Wittwer Arthur J. , Olander Jitka V. , Feder Joseph
Published: December 2008

Plasminogen activators of both urokinase‐type (u‐PA) and tissue‐type (t‐PA) have been found in conditioned medium of cultured human fibroblasts. To purify t‐PA, the total PA activity from hectoliter quantities of conditioned medium was first concentrated with about 10‐fold increase in specific activity via zinc chelate‐sepharose affinity chromatography. Three different methods were employed in an attempt to separate t‐PA from u‐PA: (a) concanavalin A‐sepharose affinity chromatography; (b) fibrin‐celite affinity chromatography; and (c) immunoaffinity chromatography using anti‐tPA monoclonal antibody immobilized on sepharose. Of the three methods, only the monoclonal antibody procedure effected complete separation of the two enzymes. t‐PA was subsequently purified to homogeneity using size exclusion, high performance liquid chromatography followed by p‐aminobenzamidine‐agarose affinity chromatography.
Scaling‐Up of Affinity Chromatography By Radial‐Flow Cartridges
Authors: Huang Stanley H. , Roy Sujeta , Hou Kenneth C. , Tsao George T.
Published: December 2008

Although affinity chromatography is an efficient separation method, impediments to its large scale applications include difficulty in predicting column behavior after scaling‐up and lack of suitable solid matrix support for fast flow operations. The introduction of radial‐flow chromatography and a modified cellulose support has overcome the impediments. Radial chromatography has advantages in low pressure drop at fast flow rate and in linear scaling‐up. The performances of the cellulose support is studied by attaching two bioaffine ligands to it and observing the efficiency in enzyme purification. Application of a radial‐flow affinity cartridge to remove proteases in human plasma shows 70% efficiency after one‐pass treatment.
Ethephon Enhancement of Secondary Metabolite Synthesis in Plant Cell Cultures
Authors: Cho G. H. , Kim D. I. , Pedersen H. , Chin C‐K.
Published: December 2008

Addition of an ethylene precursor, ethephon, was studied in plant‐cell‐suspension cultures of Coffea arabica and Thalictrum rugosum as an enhancer of secondary metabolite production. In both cases the compound was able to stimulate alkaloid production, even though the biochemical pathways are widely different. This suggests that ethephon, or more directly ethylene, may be valuable in increasing secondary metabolite levels in a variety of cell‐suspension culture systems.
Construction and Characterization of a Temperature‐Sensitive Expression System in Recombinant Yeast
Authors: Silva Nancy Anderson Da , Bailey James E.
Published: December 2008

A temperature‐regulated system for the expression of cloned genes has been developed and studied in recombinant yeast. A temperature‐sensitive (ts) strain of Saccharomyces cerevisiae was constructed which, in conjunction with plasmid promoters controlled by the yeast galactose regulatory circuit, allows induction of cloned gene product synthesis by temperature‐shift. Induction of cloned gene expression by temperature‐shift in the ts strain was compared with induction by galactose addition in a non‐ts, but otherwise identical, strain. In batch fermentations at 35°C, the levels of product protein produced by temperature‐shift induction were comparable or better than those produced by galactose induction. However, higher levels were formed by galactose induction at the preferred growth temperature of 30°C. At either temperature, β‐galactosidase synthesis was greatest when the ts strain was cultivated in galactose‐containing medium. Continuous culture experiments were performed to further characterize and compare the two induction methods. Induction by galactose addition at 30°C was superior, indicating the importance of temperature for cell growth and cloned gene expression.
The Solubility of Amino Acids in Mixtures of Water and Aliphatic Alcohols
Authors: Orella C. J. , Kirwan D. J.
Published: December 2008

Crystallization is one of the most frequently utilized separation operations in the pharmaceutical industry as a purification step and for producing a solid product with a desired particle size distribution. This crystallization or precipitation is often effected by the addition of a miscible nonsolvent that drastically reduces the solubility of the solute in the mixture. In order to characterize the important phenomena in the crystallization of molecules that have biological significance, we have studied the fundamentals of the crystallization of biochemicals by nonsolvent addition using a model system: the crystallization of amino acids from mixtures of water and aliphatic alcohols.
Displacement Chromatography of Proteins Under Elevated Flow Rate and Crossing Isotherm Conditions
Authors: Subramanian Guhan , Cramer Steven M.
Published: December 2008

Displacement chromatography was employed for the preparative‐scale separation of four‐component protein mixtures. The feed components were both purified and concentrated during the separation process. Protein displacement was successfully carried out at elevated flow rates with minimal effect on bioproduct purity resulting in high bioproduct throughput. The effect of “crossing” adsorption isotherms on the displacement chromatographic process was investigated. Under adsorptive conditions where the protein isotherms cross, the displacement system was unable to separate the feed components. On the other hand, subtle changes in the adsorption conditions readily “separated” the protein isotherms, enabling the purification of the proteins of interest by displacement chromatography. This paper extends the scope of biopolymer displacement chromatography to more complex feed mixtures and elevated flow rates, and demonstrates how protein isotherms can be manipulated to effect the efficient purification of biopolymers by displacement chromatography.