bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biological Neural Control
Authors: Grzywacz Norberto M. , Padilla Mónica 
Published: April 2006

AbstractNeural control refers to the manipulation of inputs to particular structures of the nervous system to cause desirable output behavior. There are two kinds of neural control mechanisms, namely, closed loop and open loop. As an example of the former, the hypothalamus receives sensory information from the body to control its temperature. If the environmental temperature rises, then the hypothalamus makes the skin sweat to cool the body. This temperature control is called closed loop, because after the output behavior is modified, new sensory data are taken to see whether the output behavior should be increased or reduced. Hence, closed‐loop neural control depends on feedback information about the effects of output behavior. In contrast, the nervous system can sometimes perform open‐loop control. This form of control does not rely on feedback to correct erroneous outputs, and thus, the nervous system must rely on knowledge of system behavior to compute its output. Therefore, open‐loop neural control requires accurate models of the system. Although such control can be less precise, it has the advantage of speed, because it does not require feedback for computations. One example of open‐loop neural control occurs in the first 100 ms of the eye trying to do smooth pursuit of a target in the visual field. This period of pursuit is open loop, because no visual feedback is available because of the delays in the visual system. Thereafter, visual feedback (and other sources of information) is available to close the loop, which improves performance.
Photomultipliers
Authors: Donati Silvano 
Published: April 2006

Abstract
Photomultipliers (PMTs) are ideally suited in a number of photodetection measurements, provide a wide dynamic range and an excellent linearity, with a good speed of response and a very low excess noise. PMTs are available in a variety of formats, with an ample choice of spectral responses, ranging from ultraviolet (down to λ≈100 nm) to infrared (up to λ≈1700 nm with NEA photocathodes).
This chapter begins by presenting a short introduction to PMT operation followed by an analysis of the elements of the PMT — photocathode, electron optics, and multiplying chain and related parameters. A section is devoted to summarize the theoretical results of PMT response. Then, specifications and characteristics of PMTs are discussed. Finally, the most widespread applications of PMTs to measurements and the performance that can be obtained are reviewed.
Trees, Evolutionary
Authors: Dorman Karin 
Published: April 2006

Abstract
An evolutionary tree is a mathematical and graphical representation of the evolutionary history relating a sample of biological organisms. A number of methods have been developed to infer evolutionary trees, including maximum parsimony, maximum likelihood, Bayesian, and distance‐matrix methods. All methods make numerous assumptions that are more or less violated by real biological data, sometimes leading to systematic inference error. Random error also affects tree estimates, but can be ascertained using asymptotic theory, the bootstrap, or via the posterior probability in Bayesian approaches. Although phylogenetic trees are intrinsically interesting to systematists and evolutionary biologists, they are also indelibly linked to many other analyses of biological data. Treating samples from evolutionarily linked organisms as independent can be misleading. Tree inference as part of the analysis can account for the dependence among samples and facilitate interpretation of complex biological datasets.
Upper Airway Mechanics
Authors: Badr M. Safwan , Rowley James A. 
Published: April 2006

Abstract
Understanding the mechanics of the upper airway is critical to the research on the pathophysiology of upper airway obstruction. This article will review the determinants of upper airway patency including the upper airway dilating muscles, the transmural pressure across the airway, pharyngeal compliance, and craniofacial structure. During sleep, loss of the wakefulness stimulus to breathe results in decreased upper airway caliber and increased resistance. Models that characterize the relationship between pressure and flow of the upper airway during sleep and that explain upper airway collapsibility during sleep will be presented. Finally, a proposed scheme of the pathophysiology of upper airway collapse during sleep will be presented.
Oral gene delivery: Design of polymeric carrier systems shielding toward intestinal enzymatic attack
Authors: Martien Ronny , Loretz Brigitta , Schnürch A. B. 
Published: April 2006

AbstractThe gastrointestinal tract poses a variety of morphological and physiological barriers to the expression of target genes. The aim of this study was to evaluate the stability of cationic polymer/pDNA nanoparticles toward salts and enzymes of the intestinal fluid. Within this study, a chitosan–enzyme inhibitor conjugate has been generated and characterized. Based on this conjugate, nanoparticles with pDNA were generated to enhance transfection rate in oral gene delivery. The enzyme inhibitor aurintricarboxylic acid (ATA) was covalently bound to chitosan to improve the enzymatic stability of nanoparticles formed with this polymer and pDNA. Chitosan–ATA/pDNA nanoparticles showed a size of 98.5 ± 26 nm and a zeta potential of −13.26 ± 0.24 mV (n = 3–4). Stability studies with salt solution, lysozyme, DNase, and freshly collected porcine intestinal fluid showed that chitosan–ATA/pDNA nanoparticles are significantly (p < 0.05) more stable than unmodified chitosan/pDNA nanoparticles. Apart from improved stability, chitosan–ATA/pDNA nanoparticles showed a 2.6‐fold higher transfection rate than chitosan/pDNA nanoparticles in the Caco‐2 cell line, thus creating a promising carrier for orally administered therapeutic genes. © 2006 Wiley Periodicals, Inc. Biopolymers 83:327–336, 2006This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
A risk index for early node-negative breast cancer
Authors: Boyages J , Taylor R , Chua B , Ung O , Bilous M , Salisbury E , Wilcken N 
Published: April 2006

AbstractBackgroundThis study compared the application of the St Gallen 2001 classification with a risk index developed at the New South Wales Breast Cancer Institute (BCI Index) for women with node-negative breast cancer treated without adjuvant systemic therapy.MethodsThe BCI risk categories were constructed by identifying combinations of prognostic indicators that produced homogeneous low-, intermediate- and high-risk groups using the same variables as in the St Gallen classification.ResultsThe BCI low-risk category consisted of women aged 35 years or more with a grade 1 oestrogen receptor (ER)-positive tumour 20 mm or less in diameter, or with a grade 2 ER-positive tumour of 15 mm or less. This category constituted 40·1 per cent of patients, with a 10-year distant relapse-free survival (DRFS) rate of 97·2 per cent. The BCI intermediate-risk category included women aged 35 years or more with a grade 2 ER-positive tumour of diameter 16–20 mm, or a grade 1 or 2 ER-negative tumour measuring 15 mm or less, and comprised 12·1 per cent of the women, with a 10-year DRFS rate of 88 per cent. The high-risk category comprised 47·7 per cent of women, with a 10-year DRFS rate of 68·4 per cent.ConclusionIf confirmed in other data sets, the BCI Index may be used to identify women at low risk of distant relapse (2·8 per cent at 10 years) who are unlikely to benefit from adjuvant systemic therapy, and women at intermediate risk of distant relapse (12 per cent at 10 years) in whom the benefit of adjuvant systemic therapy is small.
The prevalence of thrombophilia in patients with symptomatic peripheral vascular disease
Authors: Vig S , Chitolie A , Bevan D , Dormandy J , Thompson M M , Halliday A 
Published: April 2006

Abstract

Background
The aim of this prospective study was to establish the prevalence of thrombophilia and hyperhomocysteinaemia using a comprehensive screen in patients with peripheral vascular disease.

Methods
A total of 150 patients with peripheral vascular disease (with an ankle brachial pressure index of less than 0·8) underwent thrombophilia screening (protein C and protein S, antithrombin, lupus anticoagulant, activated protein C resistance and factor V Leiden and prothrombin mutations). Fasting homocysteine assays were also performed.

Results
A thrombophilia defect was found in 41 patients (27·3 per cent). The commonest was protein S deficiency, found in 17 patients (11·3 per cent). Others included factor V Leiden mutation, found in 10 (6·7 per cent) and protein C deficiency, found in six (4·0 per cent). Lupus anticoagulant and prothrombin mutation were both found in six (4·0 per cent). One patient had an antithrombin deficiency. Only the presence of critical ischaemia was associated with a positive thrombophilia screen on single variable analysis (P = 0·03). Hyperhomocysteinaemia was present in over a third of the study group (37·3 per cent): 45 defined as moderate and 11 as intermediate.

Conclusion
A quarter of patients with peripheral vascular disease had evidence of thrombophilia, and a third had hyperhomocysteinaemia.
Disturbances of the microcirculation in acute pancreatitis
Authors: Cuthbertson C M , Christophi C 
Published: April 2006

AbstractBackgroundSevere acute pancreatitis is characterized by pancreatic necrosis, resulting in local and systemic inflammation. Pancreatitis affects both the systemic and pancreatic vasculature. This review focuses on the underlying processes involved in the changes of microvascular anatomy following acute pancreatitis.MethodsA Medline/PubMed search (January 1966 to December 2005) with manual cross-referencing was conducted. All relevant articles investigating the pancreatic microcirculatory anatomy and the effect of pancreatitis on the microcirculation were included.ResultsThe pancreas is susceptible to ischaemic insult, which can exacerbate acute pancreatitis. There is also increasing evidence of pancreatic and systemic microvascular disturbances in the pathogenesis of pancreatitis, including vasoconstriction, shunting, inadequate perfusion, and increased blood viscosity and coagulation. These processes may be caused or exacerbated by ischaemia–reperfusion injury and the development of oxygen-derived free radicals.ConclusionAcute pancreatitis impairs the pancreatic and systemic microcirculation, which is a key pathological process in the development of severe necrotizing disease.
Hepatocyte morphology and kinetics after portal vein embolization
Authors: Komori K , Nagino M , Nimura Y 
Published: April 2006

Abstract

Background
Macroscopic volume changes after portal vein embolization (PVE) can be assessed accurately by computed tomography, but histological changes remain poorly understood. The aim of this study was to clarify hepatocyte morphology and kinetics after PVE.

Methods
The resected livers from 25 patients who underwent extended hepatectomy after PVE and five normal livers were examined using hepatocyte paraffin 1 staining for histomorphometric analysis of hepatocytes. Cell kinetics were determined by Ki-67 staining and terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick-end labelling assay. Kupffer cells were examined by CD68 immunostaining.

Results
The number of hepatocytes was similar in the embolized lobe, non-embolized lobe and normal liver, but hepatocyte volume was greater in the non-embolized lobe than in the embolized lobe (P = 0·017). The Ki-67 labelling index was higher in the non-embolized lobe (P &lt; 0·001) whereas the apoptotic index was higher in the embolized lobe (P &lt; 0·001). There were more Kupffer cells per unit area in the embolized lobe (P &lt; 0·001).

Conclusion
Hepatocyte hypertrophy and replication leads to volume enlargement of the non-embolized hepatic lobe, whereas hepatocyte atrophy and apoptosis causes a decrease in volume of the embolized lobe.
Randomized clinical trial of splenectomy versus splenic preservation in patients with proximal gastric cancer
Authors: Yu W , Choi G S , Chung H Y 
Published: April 2006

Abstract

Background
Preservation or removal of the spleen during total gastrectomy for proximal gastric cancer is a matter of debate.

Methods
A randomized clinical trial included patients with gastric adenocarcinoma who underwent total gastrectomy either with (104 patients) or without (103) splenectomy. Postoperative outcome in the two groups was compared, including morbidity, mortality and survival.

Results
Gastrectomy combined with splenectomy tended to be associated with slightly higher morbidity and mortality rates, a slightly greater incidence of lymph node metastasis at the splenic hilum and along the splenic artery, and marginally better survival, but there were no statistically significant differences between the groups. Splenectomy had no impact on survival in patients with metastatic lymph nodes at the hilum of the spleen or in those with metastatic lymph nodes along the splenic artery.

Conclusion
These results do not support the use of prophylactic splenectomy to remove macroscopically negative lymph nodes near the spleen in patients undergoing total gastrectomy for proximal gastric cancer.
The Activation of Electrophile, Nucleophile and Leaving Group during the Reaction Catalysed by pI258 Arsenate Reductase
Authors: Roos Goedele , Loverix Stefan , Brosens Elke , Van Belle Karolien , Wyns Lode , Geerlings Paul , Messens Joris 
Published: April 2006

AbstractThe reduction of arsenate to arsenite by pI258 arsenate reductase (ArsC) combines a nucleophilic displacement reaction with a unique intramolecular disulfide cascade. Within this reaction mechanism, the oxidative equivalents are translocated from the active site to the surface of ArsC. The first reaction step in the reduction of arsenate by pI258 ArsC consists of a nucleophilic displacement reaction carried out by Cys10 on dianionic arsenate. The second step involves the nucleophilic attack of Cys82 on the Cys10–arseno intermediate formed during the first reaction step. The onset of the second step is studied here by using quantum chemical calculations in a density functional theory context. The optimised geometry of the Cys10–arseno adduct in the ArsC catalytic site (sequence motif: Cys10–Thr11–Gly12–Asn13–Ser14–Cys15–Arg16–Ser17) forms the starting point for all subsequent calculations. Thermodynamic data and a hard and soft acids and bases (HSAB) reactivity analysis show a preferential nucleophilic attack on a monoanionic Cys10–arseno adduct, which is stabilised by Ser17. The P‐loop active site of pI258 ArsC activates first a hydroxy group and subsequently arsenite as the leaving group, as is clear from an increase in the calculated nucleofugality of these groups upon going from the gas phase to the solvent phase to the enzymatic environment. Furthermore, the enzymatic environment stabilises the thiolate form of the nucleophile Cys82 by 3.3 pH units through the presence of the eight‐residue α helix flanked by Cys82 and Cys89 (redox helix) and through a hydrogen bond with Thr11. The importance of Thr11 in the pKa regulation of Cys82 was confirmed by the observed decrease in the kcat value of the Thr11Ala mutant as compared to that of wild‐type ArsC. During the final reaction step, Cys89 is activated as a nucleophile by structural alterations of the redox helix that functions as a pKa control switch for Cys89; this final step is necessary to expose a Cys82–Cys89 disulfide.
Induced‐Fit Recognition of DNA by Small Circular Oligonucleotides
Authors: Escaja Núria , Gómez‐Pinto Irene , Viladoms Júlia , Rico Manuel , Pedroso Enrique , González Carlos 
Published: April 2006

AbstractWe have investigated the molecular interaction between cyclic and linear oligonucleotides. We have found that short cyclic oligonucleotides can induce hairpinlike structures in linear DNA fragments. By using NMR and CD spectroscopy we have studied the interaction of the cyclic oligonucleotide d<pCCTTCGGT> with d<pCAGTCCCT>, as well as with its two linear analogs d(GTCCCTCA) and d(CTCAGTCC). Here we report the NMR structural study of these complexes. Recognition between these oligonucleotides occurs through formation of four intermolecular Watson–Crick base pairs. The three‐dimensional structure is stabilized by two tetrads, formed by facing the minor‐groove side of the Watson–Crick base pairs. Overall, the structure is similar to those observed previously in other quadruplexes formed by minor‐groove alignment of Watson–Crick base pairs. However, in this case the complexes are heterodimeric and are formed by two different tetrads (G:C:A:T and G:C:G:C). These complexes represent a new model of DNA recognition by small cyclic oligonucleotides, increasing the number of potential applications of these interesting molecules.
Synthesis and Biological Evaluation of SERMs with Potent Nongenomic Estrogenic Activity
Authors: Tobias Sandra C. , Qiu Jian , Kelly Martin J. , Scanlan Thomas S. 
Published: April 2006

AbstractWe have synthesized novel SERMs that activate a rapid response in CNS neurons, but which lack the ability to bind to the nuclear estrogen receptors (ERα and ERβ). These compounds are analogues of 4‐hydroxytamoxifen, but unlike 4‐hydroxytamoxifen, they do not exist as a mixture of E/Z isomers. They contain a carboxamide insertion between the olefin and basic phenyl side chain, which results in more stable geometric isomers. The amide insertion also eliminates their ability to bind to the nuclear estrogen receptors, and hence, they are unable to modulate ER‐mediated gene transcription as do classical estrogens and SERMs. We show that one of these analogues, ST‐X, elicits a potent nongenomic estrogen response in the CNS by rapidly inhibiting GIRK activation in hypothalamic γ‐aminobutyric acid (GABA) and proopiomelanocortin (POMC) neurons. To our knowledge, ST‐X is the only SERM that modulates rapid estrogen responses, but which lacks nuclear ER activity.
Hydrogen Electrocatalysis
Authors: Kibler Ludwig A. 
Published: April 2006

AbstractA selection of recent theoretical and experimental studies on electrolytic hydrogen evolution is presented. It is demonstrated with well‐defined model surfaces that this reaction is a very structure‐sensitive process. Crystallographic orientation, defect density and surface composition are parameters that determine the local geometric and electronic surface structure, and are thus crucial for the electrocatalytic activity as characterised by the exchange current density. The observed trends can be understood within a recent theory by J. K. Nørskov et al., which is based on density functional calculations and which emphasises the impact of hydrogen chemisorption energies on the reaction rate, that is, on the exchange current density. The particular electrocatalytic activities of ultrathin metal films and of nanostructures are addressed.
Dynamic Light‐Scattering Analysis of the Electrostatic Interaction of Hexahistidine‐Tagged Cytochrome P450 Enzyme with Semiconductor Quantum Dots
Authors: Ipe Binil Itty , Shukla Anuj , Lu Huachang , Zou Bo , Rehage Heinz , Niemeyer Christof M. 
Published: April 2006

AbstractCurrently, there is great interest in the development of methods suitable for determining the stoichiometry of biomolecules attached to nanoparticles. We describe the use of the dynamic light‐scattering technique (DLS) to determine the stoichiometry of the protein cytochrome P450BSβattached to CdS and CdSe quantum dots (QDs). The enzyme‐conjugated QDs have different diffusion characteristics compared to the QD and enzyme precursors, expressed in their size, scattering intensity as well as zeta‐potential values. The significant enhancement of the scattering intensity of QDs observed upon conjugation with the P450BSβdue to the refractive‐index increment and the systematic variation in zeta potential resulting from charge neutralization of the anionic QDs by the cationic histidine‐tagged P450BSβhave been used for stoichiometry determination.
Regular use of low‐phosphorus milk significantly improves dietary satisfaction of patients without changing their serum phosphorus
Authors: Oliverio Sandra , Atcher Leah 
Published: April 2006

AbstractBackgroundControl of serum phosphorus has become one of the most critical issues in the management and welfare of the population of those with stage 5 chronic kidney disease (CKD). Milk is a food staple desired by many in this population, yet it is a food especially high in phosphorus. This study was designed to test the acceptance of DairyDelicious low‐phosphorus milk by CKD stage 5 patients and to evaluate its effect on their serum phosphorus levels.MethodsTwenty CKD stage 5 patients who liked milk but avoided it because of its high phosphorus content were given a 1‐month supply of DairyDelicious low‐phosphorus (116 mg/8 fl oz), low‐potassium (197 mg/8 fl oz) milk. The serum phosphorus, calcium, and albumin levels of the patients were measured at the beginning and end of the study. Baseline and poststudy questionnaires were used to survey patient satisfaction.ResultsThe serum phosphorus levels of the participants were not significantly changed at the end of the study. All study participants reported that they enjoyed the low‐phosphorus milk; most stated that they were generally happier with their diet and that they used fewer high‐phosphorus foods during the month.ConclusionsDairyDelicious low‐phosphorus milk is an important adjunct to the diet of most CKD stage 5 patients who use or drink milk. Use of this product permits expansion of food choices and promotes patient diet satisfaction without increasing serum phosphorus.
Two‐stage anterotransposition of the brachial vein as the new option for native vascular access for hemodialysis: A report of 3 cases
Authors: Przywara Stanislaw , Wronski Jacek , Terlecki Piotr , Zubilewicz Tomasz , Feldo Marcin , Skublewska‐Bednarek Anna 
Published: April 2006

AbstractBackgroundWe present 3 cases of 2‐stage anterotransposition of the brachial vein to be considered the last option for native vascular access for hemodialysis before forearm/upper arm graft placement.MethodsThree patients with chronic renal insufficiency were admitted for the creation of vascular access for hemodialysis. Physical examination, confirmed by ultrasonography, revealed the absence of adequate cephalic and basilic veins. In each case, precise color Doppler ultrasound examination showed a brachial artery with the appropriate diameter and 2 wide brachial veins joining into 1 axillary vein in the axillary fossa. Surgery was performed in 2 stages. In the first stage, one of the brachial veins was anastomosed with the brachial artery end to side in the cubital fossa. The fistula was left for 4 weeks to mature, with the brachial vein in its anatomical location. During the second stage, the entire length of the brachial vein was exposed via 1 longitudinal incision from cubital fossa up to armpit. Mobilized vein was subcutaneously transposed to an anterior location.ResultsAt present, 8–20 months after the procedure, venous pressures are within accepted ranges and hemodialysis is adequate.ConclusionsOur technical report confirms that the brachial vein can be utilized as the last option for the creation of native vascular access on the upper arm. We recommend that the surgery be performed in 2 stages. Maturation of the vein in its anatomical location, which occurs between the first and second stages of surgery, assures proper dilatation and thickening of the vein, making it better able to resist the extensive dissection and transposition during the second stage.