bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enzymatic synthesis of amoxicillin: Avoiding limitations of the mechanistic approach for reaction kinetics
Authors: Gonçalves Luciana R.B. , Sousa Ruy , Fernandez‐Lafuente Roberto , Guisan Jose M. , Giordano Raquel L.C. , Giordano Roberto C. 
Published: October 2002

AbstractA recurrent doubt that occurs to the enzyme‐kinetics modeler is, When should I stop adding parameters to my mechanistic model in order to fit a non‐conventional behavior? This problem becomes more and more involving when the complexity of the reaction network increases. This work intends to show how the use of artificial neural networks may circumvent the need of including an overwhelming number of parameters in the rate equations obtained through the classical, mechanistic approach. We focus on the synthesis of amoxicillin by the reaction of p‐OH‐phenylglycine methyl ester and 6‐aminopenicillanic acid, catalyzed by penicillin G acylase immobilized on glyoxyl‐agarose, at 25°C and pH 6.5. The reaction was carried on a batch reactor. Three kinetic models of this system were compared: a mechanistic, a semi‐empiric, and a hybrid–neural network (NN). A semi‐empiric, simplified model with a reasonable number of parameters was initially built‐up. It was able to portray many typical process conditions. However, it either underestimated or overestimated the rate of synthesis of amoxicillin when substrates' concentrations were low. A more complex, full‐scale mechanistic model that could span all operational conditions was intractable for all practical purposes. Finally, a hybrid model, that coupled artificial neural networks (NN) to mass‐balance equations was established, that succeeded in representing all situations of interest. Particularly, the NN could predict with accuracy reaction rates for conditions where the semi‐empiric model failed, namely, at low substrate concentrations, a situation that would occur, for instance, at the end of a fed‐batch industrial process. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 622–631, 2002.
Performance analysis of dynamic channel assignment algorithms in cellular mobile systems with hand‐off
Authors: Cong L. , Gunawan E. , Soh C. B. , Soong B. H. , Tan P. T. , Weng W. 
Published: October 2002

AbstractIn this paper, the traffic performance of dynamic channel assignment (DCA) in cellular mobile system with hand‐off is investigated. A traffic model for cellular system incorporating hand‐off is established first. Under the framework of the model, a hand‐off priority scheme is developed to reduce the forced termination of calls in progress. This paper analyses and derives the traffic performance bound for DCA strategies with hand‐off by extending the maximum packing (MP) scheme to include the hand‐off procedure. For practical implementation, a distributed DCA algorithm (DDCA) is also proposed. A non‐priority scheme and the proposed priority scheme can be combined with either MP or DDCA. It is shown that the simulation results of DDCA scheme are comparable with the analytical bounds given by MP for both the non‐prioritized case and prioritized case. A reasonable trade‐off between the new call blocking probability and forced termination probability can be achieved by using the proposed prioritized scheme in DCA. Copyright © 2002 John Wiley & Sons, Ltd.
The use of fly ash from the combustion of poultry litter for the adsorption of chromium(III) from aqueous solution
Authors: Kelleher Brian P , O'Callaghan Marguerite N , Leahy Martin J , O'Dwyer Thomas F , Leahy J J 
Published: October 2002

AbstractFly ash, from the combustion of poultry litter, was assessed as an adsorbent for chromium(III) from aqueous solution. The adsorption process was studied as a function of temperature and time. Adsorption was best described by the Langmuir model. The adsorption of chromium(III) on the fly ash was endothermic and kinetic studies suggest that the overall rate of adsorption was pseudo‐second order. At low initial concentrations film diffusion effects contribute to limiting the overall rate of adsorption while at higher initial chromium(III) concentrations pore diffusion becomes more important. An adsorption capacity of 53 mg dm−3 was reached at 20 °C.© 2002 Society of Chemical Industry
Extraction of aconitic acid from mixtures of organic acids and cane molasses solutions using supported liquid membranes
Authors: McMurray Scott Herbert , Griffin Gregory John 
Published: October 2002

AbstractThis paper details experimental trials of aconitic acid transport from defined mixtures of organic acids (trans‐aconitic, oxalic, malic and citric) and from cane molasses solutions using a supported liquid membrane (SLM) apparatus. The SLM was impregnated with tributyl phosphate extractant combined with Shellsol 2046 diluent. The transport rates of the organic acids, bulk impurities and glucose were measured. The conditions varied were: extractant to diluent ratio (1:3–3:1), organic acid concentration (2.5–40 mg cm−3 organic acid), pH of departure phase (1–5.5) and temperature (22–80 °C). Results for the organic acid mixtures showed that aconitic acid and oxalic acid were transported at much greater rates than malic and citric acids. Aconitic acid was transported to a significant degree with recovery of 400 g kg−1 over a 24 h period. Operation at temperatures higher than 22 °C caused instability of the membrane and bulk leakage across the membrane. With molasses, the purity of the aconitic acid recovered ranged between 400 and 600 g kg−1 (dry basis) with aconitic acid transport rates of 0.17–0.25 g m−2 min−1. The extraction of other acids (oxalic, malic and citric) and impurities was significantly less, hence a process to produce high purity aconitic acid based on this method is technically feasible.© 2002 Society of Chemical Industry
Prenatal detection of a cystic fibrosis mutation in fetal DNA from maternal plasma
Authors: González‐González M. C. , García‐Hoyos M. , Trujillo M.J. , Rodríguez de Alba M. , Lorda‐Sánchez I. , Díaz‐Recasens J. , Gallardo E. , Ayuso C. , Ramos C. 
Published: October 2002

AbstractObjectivesMaternal plasma and serum are being used to detect fetal DNA by PCR in order to determine certain conditions such as fetal gender and RhD without invasive procedures. Because of the presence of maternal DNA in plasma, these approaches are limited to paternally inherited disorders or those de novo present in the fetus. We have assessed the possibility of performing the detection of a single‐gene disorder such as a fetal paternally inherited Cystic Fibrosis mutation (Q890X) in maternal plasma.MethodsThe analysis was performed at 13 weeks of gestation using DNA extracted from maternal plasma. We used a PCR amplification of the Q890X mutation and a posterior restriction analysis of the PCR product.ResultsWe were able to detect the presence of the mutation and thus the fetal condition of being a carrier of the paternal mutation.ConclusionsWe have made evident the possibility of detecting an inherited paternal mutation in a non‐invasive way at the 13thr weeks of pregnancy. This methodology could be very useful in cases of paternally inherited dominant disorders. The technical improvements in fetal DNA detection and analysis might lead to the development of new applications in the non‐invasive prenatal diagnosis field. Copyright © 2002 John Wiley & Sons, Ltd.
Crystalline silicon photovoltaic modules: characterization in the field of rural electrification
Authors: Caamaño‐Martín E. , Lorenzo E. , Lastres C. 
Published: October 2002

AbstractThe need to characterise photovoltaic modules in the general field of ensuring technical quality in photovoltaic rural electrification (PVRE) has often been pointed out. The ongoing national PVRE initiatives announced world‐wide, together with the fact that PV modules with an actual power smaller than the nominal value can still be found on the market, make it advisable to apply systematic control to supplied power procedures. This paper argues that it is possible to carry out such control in the case of crystalline silicon PV modules, by means of experiments performed outdoors under a wide range of operation conditions, and using reduced and conventional equipment. A simple characterisation procedure specifically aimed at PVRE programmes is described and validated with an extensive experimental campaign. Copyright © 2002 John Wiley & Sons, Ltd.
Safety and risk in structural engineering
Authors: Melchers Robert E 
Published: October 2002

AbstractSafety in structural engineering is an enduring issue with a long history. Extensive rules have been developed for its management, mainly for use at the design and construction stages, but are these sufficient? Increasingly, ageing, existing structures must be assessed for continued safety. Structures are part of much larger infrastructure systems and their failure may have significant system consequences. Emerging thinking suggests that for the realistic assessment of the safety of major structures, and hence the risks involved in their failure, structural engineers will need to adopt a broad risk management perspective. This will mean the adaptation of tools and techniques drawn from risk management for other potentially hazardous facilities and used in conjunction with the well‐developed techniques unique to structural reliability analysis.Major structural engineering projects may be categorized as being ‘low‐probability—high‐consequence’ types of risk. This implies that philosophies and practices for such types of risk already developed for hazardous facilities in other industries ought to be adaptable to major structural engineering projects. It is argued that such risks have relevance also for acts of war, sabotage and terrorism, provided their assessment involves appropriate inputs. Difficult societal decision processes are involved, including the management of post‐failure scenarios.
Composite steel beams with precast hollow core slabs: behaviour and design
Authors: Lam Dennis 
Published: October 2002

AbstractThis article reviews the design and behaviour of composite beams with precast hollow core slabs in multi‐storey buildings for gravity loading. A brief history of composite construction and introduction to precast–composite construction is given, followed by an overview of recent research work on various factors affecting the design. This includes the push‐off test procedure, the load–slip characteristic of the headed shear studs and the design procedures for this type of construction. Finite element modelling of the headed stud shear connectors and the composite beams with precast hollow core slabs are presented. Finally, recommendations and future research work is also suggested.
Blast loading and building robustness
Authors: Smith P D , Rose T A 
Published: October 2002

AbstractAn overview of methods of blast load quantification and aspects of building design intended to reduce the damaging effects of explosions by increasing robustness is presented. Possible blast loading scenarios range from simple free‐air bursts, loading essentially isolated buildings, to complex urban environments, with road junctions and side streets, etc., where buildings have varying amounts of frangible facade. The blast loads resulting in these scenarios are radically different, with different aspects of the pressure load dominating the type and extent of building damage. Means of calculating these time‐varying pressure loads are described.Achieving stand‐off between a vulnerable building and the source of an explosion is the single most important factor in reducing the blast load experienced by the building. Methods of achieving stand‐off in building design are discussed. The creation of adequate stand‐off may often not be possible, and the need for robust glazing systems is also essential if blast is to be keep out of buildings and contamination of the work‐place by broken glass is to be prevented. The use of laminated glass, anti‐shatter film and other measures is discussed.Existing buildings pose particular problems to engineers concerned with their protection. Several methods of strengthening or increasing the effective mass of existing buildings are described.
Quality of Life, Surgical Outcome, and Patient Satisfaction Three Years after Laparoscopic Nissen Fundoplication
Authors: Granderath Frank A. , Kamolz Thomas , Schweiger Ursula M. , Pointner Rudolph 
Published: October 2002

Quality of life data and patient satisfaction are important issues in estimating the outcome of laparoscopic antireflux surgery (LARS). Long‐term of quality of life assessment has not yet received wide attention. The aim of this prospective study was to evaluate surgical outcome, including quality of life and patient satisfaction, after laparoscopic "floppy"
Nissen fundoplication up to 3 years after surgery. Between 1994 and
1996, a total of 150 consecutive patients with severe gastroesophageal reflux disease underwent laparoscopic "floppy" Nissen fundoplication. Quality of life was evaluated using the Gastrointestinal Quality of Life Index (GIQLI). The GIQLI questionnaire was given to the patients prior to surgery, and again 3 months, 1 year,
and 3 years postoperatively. In addition, 24‐hour pH monitoring and esophageal manometry were performed preoperatively and at each follow‐up date. Finally, surgical side‐effects and patient satisfaction with the surgical outcome were evaluated 3 years after LARS.
Postoperatively lower esophageal sphincter pressure improved significantly in all patients, whereas pH values showed normal data in all but 5 patients. Before surgery, all patients had a poor quality of life (GIQLI score, 90.1 ± 8.9 points). Postoperatively, GIQLI improved significantly (p <.01) and remained stable for at least 3 years, with a mean value of 123.7 ± 9.8 points.
This is comparable to 122.6 ± 8.5 points of healthy individuals.
Ninety‐eight percent of the patients rated their satisfaction with surgical treatment as excellent or good and would undergo surgery again if necessary. Nine patients suffered from minimal surgical side‐effects, but these did not significantly impair their quality of life. Laparoscopic reoperation was performed in 2 patients 3 months after initial surgery because of severe dysphagia. Both patients were free of symptoms 3 years after surgery. The efficacy and long‐term outcome of treatment of gastroesophageal reflux disease with laparoscopic "floppy" Nissen fundoplication can be evaluated by objective testing, but also with subjective judgment of the patient,
including quality of life assessment.
Intravenous Calcium Injection Test Is a Novel Complementary Procedure in Differential Diagnosis for Gastrinoma
Authors: Wada Michihiko , Komoto Izumi , Doi Ryuichiro , Imamura Masayuki 
Published: October 2002

Abstract
The current study evaluated efficacy of the intravenous calcium injection test as a new diagnostic approach to clarify the existence of gastrinoma, which often goes undetected with routine testing. Twenty‐six patients with hypergastrinemia were studied. For the calcium injection test, blood samples were taken from
12 patients with hypergastrinemia (HG), and three healthy volunteers,
and one patient with nonfunctioning endocrine tumor in the pancreas
(control). We compared results of the calcium injection test with those of the secretin test and the selective arterial secretagogue injection
(SASI) test. The SASI test with secretin was performed in 24 of 26
patients with hypergastrinemia, including 22 of 24 patients with Zollinger‐Ellison syndrome (ZES). Accuracy in the diagnosis of tumor localization by the SASI test was 95% (21 of 22) in ZES patients. The secretin test was negative in 3 of 21 patients with ZES (14%). Either the secretin test or the SASI test was positive in 22 of 23 patients
(96%). The calcium injection test was administered to 12 patients in the HG group and 4 controls. The HG group showed significantly higher serum gastrin levels than those of the control group in the calcium injection test. Eight of 10 ZES patients (80%) had a positive calcium injection test. We could diagnose gastrinomas in 100% of ZES patients by either the calcium injection test or the secretin test. We have thus confirmed the efficacy of the intravenous calcium injection test in the diagnosis of gastrinoma. The calcium injection test could become an adjunct in the diagnosis of gastrinoma, which often goes undetected with routine testing.
Can Dynamic Gadolinium‐enhanced Magnetic Resonance Imaging with Chemical Shift Studies Predict the Status of Adrenal Masses?
Authors: Prager Gerhard , Heinz‐Peer Gertraud , Passler Christian , Kaczirek Klaus , Schindl Martin , Scheuba Christian , Vierhapper Heinrich , Niederle Bruno 
Published: October 2002

Endoscopic adrenalectomy represents the new gold standard in the surgical treatment of benign adrenal lesions up to 6 cm. In some cases lesions larger than 10 cm have been removed laparoscopically to offer the patient the advantages of the minimally invasive technique. The larger the diameter of an adrenal lesion, the greater the probability of malignancy. In a prospective study 130
consecutive patients (88 women, 42 men; mean age 47.8 years) with 137
adrenal lesions earmarked for surgery underwent preoperative gadolinium‐enhanced magnetic resonance imaging (MRI) with chemical shift studies (CSS). The aim of this study was to predict the status (benign, borderline, malignant) of adrenal lesions by MRI irrespective of tumor size. There were 14
patients with malignant tumors, 3 had borderline tumors (epithelial tumors with high malignant potential), and the remaining 120 had benign adrenal lesions. Five malignant lesions (36%) had a diameter < 6
cm. MRI correctly predicted 11 of 14 malignant tumors (1 malignant pheochromocytoma and 2 adrenocortical carcinomas had false‐negative results), 117 of 120 benign lesions, and 2 of 3 borderline lesions. All but two malignant tumors were operated on using open surgery; 82 (68%)
of 120 benign adrenal lesions were treated using the transperitoneal laparoscopic approach. Tumor size alone is not suitable for predicting the status of adrenal lesions. Dynamic gadolinium‐enhanced MRI with CSS can predict the status of at least 95% of adrenal lesions. Tumors
> 6 cm classified as benign by preoperative MRI may be removed laparoscopically by endocrine surgeons experienced in endoscopic adrenalectomy.
Minimally Invasive Video‐assisted Thyroidectomy: Multiinstitutional Experience
Authors: Miccoli Paolo , Bellantone Rocco , Mourad Michel , Walz Martin , Raffaelli Marco , Berti Piero 
Published: October 2002

Minimally invasive video‐assisted thyroidectomy (MIVAT) was described in 1998. In this study we collected the experience of four third‐level referral centers that adopted this technique. A total of 336 patients (279 females, 57 males) were selected for MIVAT. Selection criteria were thyroid volume <15
ml, nodules not exceeding 3.5 cm of diameter, and an absence of thyroiditis, previous neck surgery, or previous irradiation. The procedure, totally gasless, is carried out through a 15 mm central incision above the sternal notch. Dissection is performed under endoscopic vision using conventional and endoscopic instruments. The mean operating time was 69.4 ± 30.6 minutes for lobectomy (range
20–150 minutes) and 87.4 ± 43.5 minutes for total thyroidectomy
(range 30–220 minutes). The mean postoperative stay was 1.9 ±
0.8 days. Postoperative complications were 7 transient and 1 definitive recurrent nerve palsies and 11 cases of hypoparathyroidism (9
transient, 2 definitive). Conversion to open surgery was necessary in
15 patients (4.5%). This study confirms in a large number of cases the safety and feasibility of MIVAT, even in different surgical settings where similar results were achieved. The complication rate was not different from that of standard thyroidectomy. Although the operating time appears longer than with conventional procedures, the learning curve demonstrates a sharp decrease with increasing experience and the introduction of new technologies. The number of patients eligible for this approach remains low, thereby limiting its use, but it should be considered a valid option in selected surgical centers, offering some advantages to patients in terms of cosmetic results and postoperative distress.
Laparoscopic Radiofrequency Ablation of Neuroendocrine Liver Metastases
Authors: Berber Eren , Flesher Nora , Siperstein Allan E. 
Published: October 2002

We previously reported on the safety and efficacy of laparoscopic radiofrequency thermal ablation (RFA) for treating hepatic neuroendocrine metastases. The aim of this study is to report our 5‐year RFA experience in the treatment of these challenging group of patients. Of the 222 patients with 803 liver primary and secondary tumors undergoing laparoscopic RFA between January 1996 and August 2001, a total of 34 patients with 234 tumors had neuroendocrine liver metastases. There were 25 men and 9 women with a mean ± SEM age of 52 ± 2 years who underwent 42
ablations. Primary tumor types included carcinoid tumor in 18 patients,
medullary thyroid cancer in 7, secreting islet cell tumor in 5, and nonsecreting islet cell tumor in 4. There was no mortality, and the morbidity was 5%. The mean hospital stay was 1.1 days. Symptoms were ameliorated in 95%, with significant or complete symptom control in
80% of the patients for a mean of 10+ months (range 6–24 months). All patients were followed for a mean ± SEM of 1.6 ± 0.2 years
(range 1.0–5.4 years). During this period new liver lesions developed in 28% of patients, new extrahepatic disease in 25%, and local liver recurrence in 13%; existing liver lesions progressed in 13%.
Overall 41% of patients showed no progression of their cancer. Nine patients (27%) died. Mean ± SEM survivals after diagnosis of primary disease, detection of liver metastases, and performance of RFA were 5.5 ± 0.8 years, 3.0 ± 0.3 years, and 1.6 ± 0.2
years, respectively. Sixty‐five percent of the patients demonstrated a partial or significant decrease in their tumor markers during follow‐up. In conclusion, RFA provides excellent local tumor control with overnight hospitalization and low morbidity in the treatment of liver metastases from neuroendocrine tumors. It is a useful modality in the management of these challenging group of patients.