bluuebunny/crossref_metadata_2025 huggingface dataset:
Cystic pancreatic tumors (CPT): Predictors of malignant behavior
Authors: Javle Milind , Shah Pankaj , Yu Jihnhee , Bhagat Vishal , Litwin Alan , Iyer Renuka , Gibbs John
Published: February 2007

Background and Objectives

Due to widespread use of imaging studies, increasing cystic pancreatic tumor (CPT) cases are being detected. The diagnosis of malignancy in CPT cases requires pancreatectomy. Clinical and laboratory characteristics of CPT may predict underlying malignancy.

Methods

CPT cases treated between 1994 and 2004 at our institution were included. Pseudocysts were excluded. Serous cystadenoma (SCA), mucinous cystadenoma (MCA), intrapapillary mucinous tumor, cystic endocrine tumor, and lymphoepithelial cysts were classified as benign or pre‐malignant. Serous cystadenocarcinoma (SCACA), mucinous cystadenocarcinoma (MCACA), and adenocarcinoma (ACA) were classified as malignant.

Results

Thirty‐five patients had histological confirmation. Median age was 65 years. Male/female ratio was higher in malignant group (P = 0.0284). Weight loss and abdominal mass were more prevalent in malignant group (P = 0.042 and 0.028, respectively). Malignant lesions were larger, associated with local invasion (superior mesenteric artery (SMA), superior mesenteric vein (SMV), portal vein (PV) complex or celiac encasement) and CA 19‐9 elevation. On univariate analyses, local invasion (P = 0.0029), negative surgical intervention (P = 0.0010), presence of ACA (P = 0.0044), or malignant CPT (P = 0.0018) were associated with shorter survival. On a multivariate analysis, local invasion was associated with shorter survival [Hazard ratio (HR) = 4.322, P = 0.0218], while surgical intervention was associated with improved survival (HR = 0.179, P = 0.0124).

Conclusion

Male sex, abdominal mass, weight loss, larger tumor size, local invasion, and elevated CA 19‐9 were associated with malignant CPT. J. Surg. Oncol. 2007;95:221–228. © 2007 Wiley‐Liss, Inc.
Major pancreatic resections for suspected cancer in a community‐based teaching hospital: Lessons learned
Authors: Metreveli Ramaz E. , Sahm Katherine , Abdel‐Misih Raafat , Petrelli Nicholas J.
Published: February 2007

Background

The literature reports 4–10% mortality rate, 30–60% morbidity rate, and 9–29% anastomotic leak rate after pancreaticoduodenectomy (PD) performed for periampullary tumors. These data demonstrate a linear relationship between surgical volume and outcome.

Methods

The objective of this study was to evaluate the experience of a high‐volume hospital with low‐volume pancreatoduodenectomy for suspected cancer. The study was designed as a retrospective review of medical records of all patients who underwent pancreatoduodenal resection or total pancreatectomy for a suspected periampullary carcinoma between January 1994 and December 2003. The setting of the study was a community‐based teaching hospital with a general surgery residency training program.

Results

A total of 63 patients underwent pancreatoduodenal resection or total pancreatectomy. All procedures were performed by a total of 15 different surgeons; however, 27 operations were performed by one surgeon. Pre‐operative diagnosis in most cases was either a known malignancy—27 cases (43%) or a tumor of the head of the pancreas, suspicious for malignancy—36 cases (57%). One patient underwent a total pancreatectomy. In 62 patients a pancreatoduodenal resection (Whipple procedure) was performed. Post‐operative 30‐day mortality was 4.7% (three patients). Overall in‐hospital mortality was 9.5% (six patients). Ten (16.1%) had a leak of the pancreato‐jejunal anastomosis, six of which resolved with non‐operative management. Of the remaining four patients, three died from peritonitis or consequences of erosive hemorrhage.

Conclusions

Post‐operative leak of the pancreatic anastomosis represents a technical challenge. Although most of the leaks can be treated non‐operatively, those that lead to peritonitis or erosive hemorrhage warrant operative intervention. Major pancreatic resections can be performed safely with low rates of morbidity and operative mortality with careful selection of patients at a low‐volume community‐based teaching hospital. J. Surg. Oncol. 2007;95:201–206. © 2007 Wiley‐Liss, Inc.
Symmetry of electron states in semiconductor structures under a magnetic field
Authors: Tronc P. , Smirnov V. P.
Published: February 2007

We present a group‐theory analysis of the electron states in bulk and low‐dimensional semiconductor structures under a uniform magnetic field. The analysis takes into account the gauge transformations under the symmetry operations. It is shown that the symmetry operations commute in dots, rods and tubes whatever is the orientation of the magnetic field whereas they commute in layers only when the field is in the plane. The commutations properties allow using conventional symmetry groups. In bulk materials, the confinement of electrons within rods whose axes are parallel to the field makes it possible to derive approximate wavefunction symmetries from the rod group involving the geometrical symmetry operations common to the field and the crystal but excluding the translations that are not parallel to the field. An approximation of the same kind can also be made for low‐dimensional structures. Applications to bulk materials with the wurtzite or zinc blende structure as well as related nanostructures are presented. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Study on the nature of interaction of BrCl with HF, H2O, and NH3
Authors: Wu Junyong , Zhang Jingchang , Wang Zhaoxu , Cao Weiliang
Published: February 2007

By counterpoise‐corrected optimization method, the interactions of BrCl with the first‐row hydrides (HF, H2O, NH3) have been investigated at the MP2/6–311++G(3d,3p) level. To understand that the XBr‐type (X = F, O, N) structure is more stable than the corresponding hydrogen‐bonded structure in these complexes, the electronic properties were also investigated. Symmetry‐adapted perturbation theory (SAPT) analysis has been carried out to understand the nature of the weak hydrogen bond and XBr‐type interactions. On the other hand, for the weak hydrogen‐bonded complexes and the XBr‐type complexes charges transfer is well correlated with the total induction energies. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Direct characterization of intact polypeptides by matrix‐assisted laser desorption electrospray ionization quadrupole Fourier transform ion cyclotron resonance mass spectrometry
Authors: Sampson Jason S. , Hawkridge Adam M. , Muddiman David C.
Published: February 2007

We report the characterization of a recently introduced hybrid ionization source, matrix‐assisted laser desorption electrospray ionization (MALDESI), coupled to a quadrupole Fourier transform ion cyclotron resonance mass spectrometry (QFT‐ICR‐MS) system. We first demonstrate the ability of MALDESI‐QFT‐ICR MS to directly analyze and provide high mass measurement accuracy (∼1 part‐per‐million) of a polypeptide using internal calibration. Second, we show the potential of MALDESI‐QFT‐ICR MS for the top‐down characterization of multiply charged polypeptide cations. Finally, we demonstrate sub‐femtomole detection limits in MALDESI‐QFT‐ICR MS using a combination of naturally occurring peptides and their respective stable isotope labeled forms. The results presented herein demonstrate the feasibility of several potential applications for MALDESI‐QFT‐ICR MS for the direct analysis of intact biological molecules. Copyright © 2007 John Wiley & Sons, Ltd.
Corticofugal influences on thalamic neurons during nociceptive transmission in awake rats
Authors: Wang Jin‐Yan , Chang Jing‐Yu , Woodward Donald J. , Baccalá Luiz A. , Han Ji‐Sheng , Luo Fei
Published: February 2007

Pain is a multidimensional phenomenon and processed in a neural network. The supraspinal, brain mechanisms are increasingly recognized in playing a major role in the representation and modulation of pain. The aim of the current study is to investigate the functional interactions between cortex and thalamus during nociceptive processing, by observing the pain‐related information flow and neuronal correlations within thalamo‐cortical pathways. Pain‐evoked, single‐neuron activity was recorded in awake Sprague‐Dawley rats with a Magnet system. Eight‐wire microarrays were implanted into four different brain regions, i.e., the primary somatosensory (SI) and anterior cingulate cortex (ACC), as well as ventral posterior (VP) and medial dorsal thalamus (MD). Noxious radiant heat was delivered to the rat hind paws on the side contralateral to the recording regions. A large number of responsive neurons were recorded in the four brain areas. Directed coherence analysis revealed that the amount of information flow was significantly increased from SI cortex to VP thalamus following noxious stimuli, suggesting that SI cortex has descending influence on thalamic neurons during pain processing. Moreover, more correlated neuronal activities indicated by crosscorrelation histograms were found between cortical and thalamic neurons, with cortical neurons firing ahead of thalamic units. On basis of the above findings, we propose that nociceptive responses are modulated by corticothalamic feedback during nociceptive transmission, which may be tight in the lateral pathway, while loose in the medial pathway. Synapse 61:335–342, 2007. © 2007 Wiley‐Liss, Inc.
Cardiovascular hemodynamics and umbilical artery N‐terminal peptide of proB‐type natriuretic peptide in human fetuses with growth restriction
Authors: Girsen A. , Ala‐Kopsala M. , Mäkikallio K. , Vuolteenaho O. , Räsänen J.
Published: February 2007

Objective

To test our hypothesis that human fetal N‐terminal peptide of proB‐type natriuretic peptide (NT‐proBNP) secretion is increased in proportion to the severity of fetal cardiovascular compromise in intrauterine growth restriction.

Methods

This prospective cross‐sectional study consisted of 42 growth‐restricted fetuses who underwent Doppler ultrasonographic examination of cardiovascular hemodynamics within 7 days before delivery. Group 1 fetuses (n = 13) had normal umbilical artery (UA) velocimetry. Group 2 fetuses (n = 15) had abnormal UA and normal ductus venosus (DV) velocimetry. In Group 3 fetuses (n = 14), both UA and DV velocimetries were abnormal. At delivery, an UA blood sample was obtained for assessment of NT‐proBNP. Normal values for UA NT‐proBNP were determined in 49 neonates (control group) with uncomplicated pregnancy and delivery.

Results

Group 3 fetuses demonstrated greater (P < 0.05) UA and descending aorta pulsatility indices (PIs) and greater DV, left hepatic vein (LHV) and inferior vena cava PIs for veins (PIVs) than fetuses in Groups 1 and 2. Weight‐indexed cardiac outputs and ventricular ejection forces were similar among the groups. Group 3 fetuses had higher (P < 0.05) UA NT‐proBNP concentration than fetuses in Groups 1 and 2. In the control group, the 95th percentile value of UA NT‐proBNP was 518 pmol/L. In Group 3, 13/14 neonates demonstrated abnormal UA NT‐proBNP levels. The corresponding incidences were 4/13 and 7/15 in Groups 1 and 2. Significant positive correlations were found between UA, DV and LHV PIVs and UA NT‐proBNP concentrations.

Conclusion

In human fetal growth restriction, increased cardiac afterload and pulsatility in DV blood velocity waveform pattern are associated with elevated UA NT‐proBNP concentrations. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Knowledge and Expectations of Women Undergoing Cancer Genetic Risk Assessment: A Qualitative Analysis of Free‐Text Questionnaire Comments
Authors: Phelps C. , Wood F. , Bennett P. , Brain K. , Gray J.
Published: February 2007

Individuals undergoing cancer genetic risk assessment have been found to have a poor understanding of the process, which may affect how well they cope with learning their risk. This paper reports free‐text data from questionnaires completed by women undergoing a randomised controlled trial of a psychological intervention. Of the 268 women undergoing genetic assessment for familial breast/ovarian cancer risk who were invited to take part in the trial, 157 women returned research questionnaires. Of these, 97 women provided free‐text comments upon referral to a cancer genetics clinic, 62 provided comments whilst waiting for risk information (average, moderate or high), and 36 women provided comments following notification of risk. This paper reports a thematic analysis of the free‐text data. Themes reflected individuals’ poor knowledge and uncertainty about genetic risk assessment. How well individuals responded to learning their risk depended upon whether expectations had been met. Regardless of risk, individuals undergoing cancer genetic risk assessment are likely to benefit from increased information about its process and timescales, and access to increased psychological support. Free‐text comments can provide valuable data about individuals’ expectations and knowledge of genetics services.
Radiographic threshold values for hip screening in cerebral palsy
Authors: Hägglund Gunnar , Lauge-Pedersen Henrik , Persson Måns
Published: February 2007

Purpose

To analyse the consequences of using different radiographic measurements and different threshold values for hip screening in children with cerebral palsy (CP).

Methods

In a total sample of children with CP a standardised radiological follow-up of the hips was carried out as a part of a hip prevention programme. Acetabular index (AI) and migration percentage (MP) were measured on all radiographs. In this study, 1,067 radiographs of 272 children born 1992–1998 were analysed.

Results

Lateral displacement of the femoral head was common without acetabular dysplasia, and acetabular dysplasia occurred at a later stage than femoral head lateralisation. Hip dysplasia without lateral displacement of the femoral head was rare. In 16 of the 56 hips (29%) with AI ≥ 27° and in 23 of the 71 (32%) hips with MP ≥ 33% the values decreased below the threshold value without operative treatment. In hips with AI ≥ 30° only 2 of 31 hips (6%) and in hips with MP ≥ 40% only 5 of 44 hips (11%) decreased below the threshold values without operative treatment.

Conclusions

Radiographic follow-up with only measurement of the MP seems sufficient in screening for dislocation in children with CP. MP ≥ 33% is recommended as threshold for reaction or intensified observation. In children with MP ≥ 40%, the lateral displacement increased over time in most hips, thus indicating the need for operative intervention. In children with MP 33–40%, treatment should be based on other clinical signs and the progression of MP over time.
Bedeutung von Functional Food in der Geriatrie
Authors: Sieber
Published: February 2007

Man kann sagen, dass eine ausgewogene Ernährung weiterhin die beste Voraussetzung für unsere Gesundheit und auch für die Prävention von Krankheiten im Alter – inklusive der «nutritional frailty» – darstellt. Viele (Hoch)betagte vermögen einer solchen Nahrungszufuhr aber nur ungenügend nachzukommen (z.B. Alleinstehende, Personen in Langzeitpflegestrukturen mit oder ohne Demenz). Hier mag der gezielte Einsatz von «functional food» eine wichtige Alternative darstellen. Es bleibt zu hoffen, dass gerade für diese Altersgruppe die noch nur spärlich vorhandenenen Studien bald ergänzt werden. Dies auch deshalb, als sich weitere interessante Effekte von Prä- und Probiotika zeigen lassen [61–63], auch im Bereiche der Krebsprävention [64]. Wenn man den demographischen Wandel unserer Gesellschaft bedenkt und den Umstand, dass die meisten malignen Tumore eine Altersassoziation zeigen (Geronto-Onkologie), so werden wir in den kommenden Jahren sicherlich noch viel Neues auf diesem Gebiet zu hören und lesen bekommen.
Folsäure – Freiwilliger Zusatz bei diversen Lebensmitteln oder obligate Anreicherung eines Grundnahrungsmittels?
Authors: Tönz
Published: February 2007

Eine normale, landesübliche Mischkost reicht nicht aus, um den von wissenschaftlichen Gremien definierten Tagesbedarf von 400 μg Folsäure zu decken. Das Angebot diverser Folsäure-angereicherter Lebensmittel scheint deshalb berechtigt. Ob damit eine prophylaktische Wirkung auf die verschiedenen Homocystein-assoziierten Krankheiten der zweiten Lebenshälfte erwartet werden kann, ist allerdings nicht bewiesen, sondern nur fundierte Hypothese. Für die Verhütung von Neuralrohrdefekten und andern embryonalen Missbildungen und frühkindlichen Malignomen ist eine medikamentöse Prophylaxe mit 0,4–0,8 mg Folsäure notwendig, oder die generelle, d.h. obligate Anreicherung von Backmehl. Die Problematik dieser im Ausland erfolgreich erprobten Maßnahme wird diskutiert.
Four‐stream isosector approximation for canopy radiative transfer
Authors: Tian Yuhong , Dickinson Robert E. , Zhou Liming
Published: February 2007

This study develops an analytical four‐stream isosector approximation for solar radiative transfer in a homogeneous canopy, based on the approximation of four spherical sectors of isotropic intensities (constant values for light intensities). Compared to results from a multilayer radiative transfer model, the four‐stream isosector approximation substantially improves the accuracy in calculation of albedo, transmittance, and absorptance with respect to the corresponding two‐stream approximation. For direct incident radiation, it has errors mostly under 5% for leaf area index less than 5, even when sun angles are very low, while the two‐stream method has errors of about 10% or higher; more improvement is achieved in albedo and transmittance in the visible band, and transmittance and absorptance in the near‐infrared (NIR) band. For diffuse incident radiation, both the two‐stream and four‐stream approximations always have a higher accuracy in the NIR band than in the visible band, but the improvement of the four‐stream approximation is larger for the visible band than for the NIR band. In addition, they have a higher accuracy in describing canopy albedo, transmittance and absorption for direct incident radiation than for diffuse incident radiation. However, the improvement of the four‐stream is higher for diffuse incident radiation than for direct incident radiation. The inclusion of soil albedo as the low boundary does not degrade the performance of the four‐stream approximation. As an analytical model, the four‐stream approximation can be easily applied as an efficient approach to improving the parameterization of land surface radiation in climate models.
The testis‐specific human protein RBMY recognizes RNA through a novel mode of interaction
Authors: Skrisovska Lenka , Bourgeois Cyril F , Stefl Richard , Grellscheid Sushma‐Nagaraja , Kister Liliane , Wenter Philipp , Elliott David J , Stevenin James , Allain Frédéric H‐T
Published: February 2007

The RBMY (RNA‐binding motif gene on Y chromosome) protein encoded by the human Y chromosome is important for normal sperm development. Although its precise molecular RNA targets are unknown at present, it is suggested that human RBMY (hRBMY) participates in splicing in the testis. Using systematic evolution of ligands by exponential enrichment, we found that RNA stem–loops capped by a CA/UCAA pentaloop are high‐affinity binding targets for hRBMY. Subsequent nuclear magnetic resonance structural determination of the hRBMY RNA recognition motif (RRM) in complex with a high‐affinity target showed two distinct modes of RNA recognition. First, the RRM β‐sheet surface binds to the RNA loop in a sequence‐specific fashion. Second, the β2–β3 loop of the hRBMY inserts into the major groove of the RNA stem. The first binding mode might be conserved in the paralogous protein heterogeneous nuclear RNP G, whereas the second mode of binding is found only in hRBMY. This structural difference could be at the origin of the function of RBMY in spermatogenesis.
Vibrational dynamics and stability of the high-pressure chain and ring phases in S and Se
Authors: Degtyareva Olga , Hernández Eduardo R. , Serrano Jorge , Somayazulu Maddury , Mao Ho-kwang , Gregoryanz Eugene , Hemley Russell J.
Published: February 2007

The high-pressure phases of group-VI elements sulfur and selenium in their spiral chain and ring structures are examined by in situ Raman and x-ray diffraction techniques combined with first principles electronic structure calculations. The S-II, S-III, Se-I, and Se-VII having spiral chain structures and S-VI with a molecular six-member ring structure are studied in a wide P-T range. The square spiral chain structure of S-III and Se-VII is characterized by seven Raman modes that harden with increasing pressure. The calculations reproduce the observed frequencies and allow the authors to make the mode assignment. The “p-S” and “hplt” phases of sulfur reported by previous Raman studies are identified as S-II and S-III with the triangular and square spiral chain structures, respectively. The phase relations obtained by the x-ray and Raman measurements show that the high-pressure high-temperature phases of sulfur, observed by x-ray, can be induced by laser illumination at room temperature.
Total harmonic distortion of a pseudosinusoidal signal of an arbitrary wave form generator
Authors: Bayard Jean
Published: February 2007

In its simplest shape, the pseudosinusoidal signal given by an arbitrary wave form generator is constituted by a continuation of samples which involve the presence of parasitic harmonics and an increase in its total harmonic distortion (THD) value. It seems evident that the signal shape can be improved by using a linear interpolation between two consecutive samples but, to our knowledge, this improvement is not evaluated quantitatively to date. So, we propose to calculate this THD (according to the number of samples used to build the signal) with or without linear interpolation. SPICE simulations and experimental results agree with theory.
Ionization induced relaxation in solvation structure: A comparison between Na(H2O)n and Na(NH3)n
Authors: Gao Bing , Liu Zhi-Feng
Published: February 2007

The constant ionization potential for hydrated sodium clusters Na(H2O)n just beyond n=4, as observed in photoionization experiments, has long been a puzzle in violation of the well-known (n+1)−1∕3 rule that governs the gradual transition in properties from clusters to the bulk. Based on first principles calculations, a link is identified between this puzzle and an important process in solution: the reorganization of the solvation structure after the removal of a charged particle. Na(H2O)n is a prototypical system with a solvated electron coexisting with a solvated sodium ion, and the cluster structure is determined by a balance among three factors: solute-solvent (Na+–H2O), solvent-solvent (H2O–H2O), and electron-solvent (OH{e}HO) interactions. Upon the removal of an electron by photoionization, extensive structural reorganization is induced to reorient OH{e}HO features in the neutral Na(H2O)n for better Na+–H2O and H2O–H2O interactions in the cationic Na+(H2O)n. The large amount of energy released, often reaching 1eV or more, indicates that experimentally measured ion signals actually come from autoionization via vertical excitation to high Rydberg states below the vertical ionization potential, which induces extensive structural reorganization and the loss of a few solvent molecules. It provides a coherent explanation for all the peculiar features in the ionization experiments, not only for Na(H2O)n but also for Li(H2O)n and Cs(H2O)n. In addition, the contrast between Na(H2O)n and Na(NH3)n experiments is accounted for by the much smaller relaxation energy for Na(NH3)n, for which the structures and energetics are also elucidated.
Band gaps and dielectric constants of amorphous hafnium silicates: A first-principles investigation
Authors: Broqvist Peter , Pasquarello Alfredo
Published: February 2007

Electronic band gaps and dielectric constants are obtained for amorphous hafnium silicates using first-principles methods. Models of amorphous (HfO2)x(SiO2)1−x for varying x are generated by ab initio molecular dynamics. The calculations show that the presence of Hf gives rise to low-lying conduction states which explain the experimentally observed nonlinear dependence of the band gap on hafnium content. Static dielectric constants are found to depend linearly on x, supporting recent experimental data.
Wavelet excited measurement of system transfer function
Authors: Olkkonen H. , Olkkonen J. T.
Published: February 2007

This article introduces a new method, which is referred to as the wavelet excitation method (WEM), for the measurement of the system transfer function. Instead of commonly used impulse or sine wave excitations, the method uses a sequential excitation by biorthogonal symmetric wavelets. The system transfer function is reconstructed from the output measurements. In the WEM the signals can be designed so that if N different excitation sequences are used and the excitation rate is f, the sampling rate of the analog-to-digital converter can be reduced to f∕N. The WEM is especially advantageous in testing systems, where high quality impulse excitation cannot be applied. The WEM gave consistent results in transfer function measurements of various multistage amplifiers with the linear circuit analysis (SPICE) and the sine wave excitation methods. The WEM makes available new high speed sensor applications, where the sampling rate of the sensor may be considerably lower compared with the system bandwidth.
Development of an isothermal heat-conduction photocalorimeter
Authors: Dhuna Meena , Beezer Anthony E. , Morris Andrew C. , Gaisford Simon , O’Neill Michael A. A. , Hadgraft Jonathan , Connor Joseph A. , Clapham David , Frost John
Published: February 2007

Assessing photostability (particularly of pharmaceuticals) is of growing importance, but hampered by a lack of reliable, rapid experimental testing protocols and instrumentation. In particular, most approaches require irradiation of the sample separately from the analytical measurement, which increases both experimental complexity and the number of assumptions that must be made when calculating stability. One technique that may obviate this is photocalorimetry, principally because the reporter of change (heat) is measured directly as a sample is irradiated. Although not a new idea, the design challenges of photocalorimeters are complex, primarily because light power is being introduced to the calorimeter which can thus both saturate the amplifiers and swamp the response of the sample. Careful instrument design is thus paramount. The aim of this work was to develop a robust, compact, and easy to use photocalorimeter with the immediate focus of developing photostability assays for pharmaceuticals. The final instrument design, arrived at through a series of iterative design modifications, is based on a twin differential heat-conduction principle and achieves an average base line deflection of −0.04±0.11μW with light irradiating the sample cell. The performance capabilities of the instrument were demonstrated using a model system; the photodegradation of 2-nitrobenzaldehyde in solution.
Polarization contrast terahertz-near-field imaging of anisotropic conductors
Authors: Gompf Bruno , Gebert Nadine , Heer Hanna , Dressel Martin
Published: February 2007

The authors have developed a near-field spectrometer operating in the terahertz range between 30THz and 1.4THz, which consists of backward-wave oscillators as continuous-wave sources and a photoinduced aperture as near-field probe. The instrument provides the possibility of terahertz spectroscopy and imaging with subwavelength resolution utilizing an adjustable aperture, but without a complicated probe-sample distance control. Due to the strongly polarized radiation, anisotropic sample properties can be investigated on spot sizes much smaller than the wavelength. The performance is demonstrated on subwavelength sized crystals of the quasi-one-dimensional organic conductor (TMTTF)2PF6.
Poststress recovery mechanism of the negative bias temperature instability based on dispersive transport
Authors: Yang Jingfeng , Yan Baoguang , Liu Xiaoyan , Han Ruqi , Kang Jinfeng , Liao C. C. , Gan Z. H. , Liao M. , Wang J. P. , Wong W.
Published: February 2007

A mechanism based on dispersive diffusion of hydrogen in the bulk of gate dielectrics is proposed to account for the poststress recovery characteristics of negative bias temperature instability in p-channel metal-oxide-semiconductor field effect transistors (pMOSFETs). In the proposed mechanism, the diffusing hydrogen species in the gate dielectrics will occupy the localized energy states with a large width of density of states distribution, and only a part of them that occupy the energy states above a certain energy level E0 are responsible for the recovery behavior of the threshold voltage. Excellent consistency is achieved between the theory predictions and the poststress recovery characteristics observed in the pMOSFETs with oxynitride gates, which sheds some light in understanding the negative bias temperature instability.
Hematopoietic reconstitution with androgenetic and gynogenetic stem cells
Authors: Eckardt Sigrid , Leu N. Adrian , Bradley Heath L. , Kato Hiromi , Bunting Kevin D. , McLaughlin K. John
Published: February 2007

Parthenogenetic embryonic stem (ES) cells with two oocyte-derived genomes (uniparental) have been proposed as a source of autologous tissue for transplantation. The therapeutic applicability of any uniparental cell type is uncertain due to the consequences of genomic imprinting that in mammalian uniparental tissues causes unbalanced expression of imprinted genes. We transplanted uniparental fetal liver cells into lethally irradiated adult mice to test their capacity to replace adult hematopoietic tissue. Both maternal (gynogenetic) and paternal (androgenetic) derived cells conveyed long-term, multilineage reconstitution of hematopoiesis in recipients, with no associated pathologies. We also establish that uniparental ES cells can differentiate into transplantable hematopoietic progenitors in vitro that contribute to long-term hematopoiesis in recipients. Hematopoietic tissue in recipients maintained fidelity of parent-of-origin methylation marks at the Igf2/H19 locus; however, variability occurred in the maintenance of parental-specific methylation marks at other loci. In summary, despite genomic imprinting and its consequences on development that are particularly evident in the androgenetic phenotype, uniparental cells of both parental origins can form adult-transplantable stem cells and can repopulate an adult organ.
Deaths with dental anaesthetics
Authors: Bourne J. G.
Published: February 2007

Case summaries are given of 16 recent deaths in the dental chair, 15 of them associated with the administration of a general anaesthetic (given in eight cases by consultant anaesthetists) and one with a local analgesia. Contrary to what is generally supposed, deaths with dental analgesia are rarely due to errors made by the anaesthetist: the usual cause is the upright or semi‐upright position of the patient. Dental patients undergoing general anaesthesia should be treated lying down.
Prolonged curarisation following renal transplantation
Authors: ROUSE JANE M. , GALLEY R. L. A. , BEVAN D. R.
Published: February 2007

A retrospective study of postoperative respiratory morbidity in 247 patients requiring renal transplantation between 1955 and 1973 showed that 7 patients required postoperative controlled ventilation for up to 6 days. The non‐depolarising relaxants tubocurarine and pancuronium were used in only 65 patients, but all 7 cases of respiratory failure occurred in this group. This suggests that the use of these drugs in anephric patients is potentially hazardous so far as postoperative respiratory insufficiency is concerned.
Changes in serum enzyme levels following ketamine infusions
Authors: DUNDEE J.W. , FEE J.P.H. , MOORE J. , McILROY P.D.A. , WILSON D.B.
Published: February 2007

The levels of four serum enzymes, known to be elevated in toxic hepatitis, were measured preoperatively and on the 3–4th and 13–15th postoperative days in patients anaesthetised with ketamine infusions (54) or with a standard technique (64). Significant elevations in enzyme levels were considered to have occurred when the postoperative levels were outside the accepted normal range and had increased by more than 3 × SD from controls. About half the patients in each group had minor gynaecological operations and 2120 in the ketamine series had postoperative elevation of enzyme levels, with no changes in the non‐ketamine group. Following intermediate operations 14134 anaesthetised with ketamine showed abnormal enzyme levels compared with 7/34 who had standard operations. None, of the latter had more than one abnormal test as compared with six in the ketamine series. The causes and significance of these findings are not known.
Antagonists of morphine‐induced respiratory depression
Authors: GAIROLA R.L. , GUPTA P.K. , PANDLEY K.
Published: February 2007

This double blind study showed the effect of four drugs, levallorphan, naloxone, doxapram and amiphenazole, on opiate‐induced analgesia and respiratory depression. Satisfactory analgesia was induced by administration of morphine intravenously in a dose of up to 0‐33 mg/kg; such a dose, however, produced significant depression of respiration. Administration of levallorphan, naloxone, and amiphenazole produced reversal of respiratory depression and analgesia. Doxapram reversed the respiratory depression but did not alter analgesia.
A case of respiratory failure complicated by acute hypophosphataemia
Authors: BROWN E.L. , JENKINS B.A. GWYNNE
Published: February 2007

Respiratory failure due to an exacerbation of chronic obstructive airways disease is often seen by clinicians. A case in which respiratory failure was further complicated by acute hypophosphataemia is reported. Replacement phosphate therapy resulted in a dramatic improvement in the clinical condition of the patient.

The aetiology of the hypophosphataemia was thought to be a combination of acidosis, and the administration of corticosteroids, 5% dextrose and antacids.

It is suggested that hypophosphataemia may account in part for the poor prognosis associated with severe exacerbations of chronic obstructive airways disease.
Plasma cholinesterase variants and the anaesthetist
Authors: WHITTAKER MARY
Published: February 2007

Biochemical properties of plasma cholinesterase of significance to the anaesthetist are reviewed.

The role of the genetic variants of the enzyme in suxamethonium sensitivity and hyperthermia are discussed with emphasis on the pregnant patient. Altered gene frequencies of the enzyme variants in some mental disorders is commented upon.
Total intravenous anaesthesia for neurosurgery and neuroradiology
Authors: DALLAS STUART H.
Published: February 2007

A method of total intravenous anaesthesia for neurosurgery and neuroradiology is described using a continuous infusion of alphaxalone/alphadolone (Althesin) with analgesics and muscle relaxants. It has been used successfully on 272 occasions in 243 patients. The reasons for using such a technique and the advantages and disadvantages inherent in it are discussed.
An integrated pain relief service for labour: co‐operation between obstetricians, anaesthetists and midwives
Authors: Ghosh‐Ray Goures C. , Taylor A. Barrie , Alberts Frank
Published: February 2007

Epidural injections were performed by obstetricians on 1012 patients in a pain relief service in which there was clinical co‐operation between anaesthetists and obstetricians. A consultant anaesthetist collaborated in the training of staff providing the service. Midwives maintained the epidural analgesia with top‐up doses as part of their traditional role in providing pain relief in labour. Eighty‐eight per cent of patients were fully satisfied, 10‰ were helped and 2‰ had failed epidurals. The forceps rate was 30‰ and the dural tap rate 1.4‰ Junior obstetric staff in training grades can with adequate safeguards make a significant contribution to running an obstetric epidural service.
Anaesthesia for removal of carcinoid metastases
Authors: RAWLINSON W.A.L. , MARSH R.H.K. , GOAT V.A.
Published: February 2007

A case of general anaesthesia for removal of carcinoid metastases is presented. Evidence of serotonin hypersecretion was shown by raised levels of 5‐hydroxyindoleacetic acid, hypertension and tachycardia. The rarity of osteoblastic carcinoid metastases is discussed.
Applying for an appointment in anaesthesia
Authors: ZORAB JOHN S.M.
Published: February 2007

The problems involved in obtaining an appointment in anaesthetic are reviewed under the headings of ‘job selection’, ‘short‐listing’ and ‘interviews’. Advice is given on identifying suitable jobs, preparing an application and making the best impression before an interview committee. Suggested headings for applications are tabulated.
Senior registrar rotations. A survey of rotational arrangements
Authors: Barham Chris , Thompson M.A.
Published: February 2007

A questionnaire was circulated to assess the extent and nature of problems with senior registrar rotations. Proper notice of an impending move, suitable accommodation provided at the rotation hospital, and a clear indication of which hospitals are involved in the rotation should reduce the number of difficulties encountered.
Respiratory effects of Minaxolone
Authors: Puchihewa V. G. , Whitwam J. G. , Morgan M. , Lumley Jean
Published: February 2007

The respiratory effects of induction of anaesthesia with Minaxolone 0·4 mg/kg were studied following premediction with either atropine alone, lorazepam and atropine or papaveretum and hyoscine. There was no significant difference in the incidence of apnoea in the three groups, Those who received non‐narcotic premedication showed a significant increase in respiratory rate, but the minute volumes in these patients did not differ significantly from control values in the third minute after injection of minaxolone. In those who received papaveretum and hyoscine, there was no change in respiratory rate and a highly significant reduction in minute volume.
Anaphylactoid reaction to infusion of polygelatin (Haemaccel)
Authors: LUND NIELS
Published: February 2007

A series of allergic reactions to infusion of polygelatin (Haemaccel®) in six pregnant women is reported. These women and a control group of five pregnant women were studied with analysis of complement, ELISA and skin tests. No differences were found between the groups in the factors studied. It is concluded that the reactions to polygelatin were caused through direct liberation of histamine, that is, an anaphylactoid reaction.
Low dose intravenous infusion technique with ketamine
Authors: PANDIT SUJIT K. , KOTHARY SARLA P. , KUMAR SURENDRA M.
Published: February 2007

Low dose ketamine is a relatively new technique. The recommended doses vary considerably. It was therefore decided to establish the minimum dose of ketamine required to produce satisfactory analgesia, sedation and amnesia in 50% of a population of adult volunteers. Twenty adult volunteers aged 20 to 42 years were the subjects of the study. Twenty minutes following intravenous (iv) pre‐treatment with 0·3 mg of atropine and 0·2 mg/kg of diazepam each volunteer received a bolus of ketamine 1·0 mg/kg iv followed by ketamine iv infusion at the rate of either0·5 mg/kg/hour(10cases) or 1·0 mg/kg/hour (10 cases). The grade of sedation was determined on a scale of 1–5 and the frequency of amnesia was assessed using visual memory cards. Analgesia was determined by pin prick.

Diazepam alone produced no analgesia and only moderate degree of sedation. Ketamine produced satisfactory analgesia to pin prick in both the groups. Ketamine bolus produced marked sedation for about 20 min followed by moderate sedation during iv infusion in both the groups. During the iv infusion of ketamine at arate of 0·5 mg/kg/hour the amnesic effects declined to 20% in 45 minutes, while during infusion of 10 mg/kg/hour the frequency reached a maximum at 50–60%. The minimum dose of ketamine required to produce amnesia in 50% of this population was therefore 1·0 mg/kg/hour after a bolus injection of 1·0 mg/kg given iv.
Piped medical gas and vacuum systems
Authors: HOWELL R.S.C.
Published: February 2007

The principles and construction of medical gas and vacuum pipeline systems found in hospitals in the United Kingdom are described, with some reference to overseas practice.
Assessment of pain using a computer
Authors: Gerson G. R. , Gerson J.N.
Published: February 2007

Visual analogue scales are of value in the assessment of a subjective phenomenon such as pain. A method of producing such a visual scale on a computer screen is described, an audible component has also been provided on the computer to assist the patient in estimating the severity of his pain. Guidance is provided on the preparation of a programme to incorporate such a scale on a computer for use in an outpatient clinic.
Deflection of spinal needles by the bevel
Authors: DRUMMOND G.B. , SCOTT D.H.T.
Published: February 2007

Bevelled spinal needles sizes 22 and 25 gauge were passed through tough meat to assess the influence of bevel orientation on the path of the needle. The needle bent away from the bevel surface by about I mm for each centimetre of needle travel through the tissue. With an introducer, the deviation was reduced by a reduction of the distance of unsupported travel. Pencil‐point needles were less deviated.
Reversal of non‐depolarising neuromuscular block in children: a comparison of atropine and glycopyrrolate in a mixture with neostigmine
Authors: Black G. W. , Mirakhur R. K. , Keilty S. R. , Love S. H. S.
Published: February 2007

Atrapine and glycopyrrolate were compared when given in a mixture with neostigmine for the reversal of non‐depolarising neuromuscular block in children. Glycopyrrolate was an effective antimuscarinic agent and could be safely used as an alternative to atropine, although the advantages in this age group were not as marked as have been observed in adults.
Cardiovascular responses to anaesthesia
Authors: COLEMAN A.J. , JORDAN C.
Published: February 2007

Observations of heart rate, rhythm and arterial pressure during induction of anaesthesia, intubation of the trachea, and commencement of surgery were made in 42 patients divided into three comparable groups. Group 1, the control group of 15 patients, received an intravenous placebo injection prior to induction of anaesthesia; group 2, 14 patients, was given an intravenous injection of 2 mg of metoprolol, a beta‐adrenoreceptor blocking agent; group 3, 13 patients, received 4 mg metoprolol intravenously. In the placebo group, significant mean increases in heart rate of 27 and 38 beats/minute were noted at induction of anaesthesia and at intubation of the trachea respectively (p< 0·001). Heart rate was significantly reduced after metoprolol in groups 2 and 3 before anaesthesia (7·6 beats/minute, p < 0·05; and 12·9 beats/minute, p < 0·001). The increases which occurred after induction of anaesthesia (13·7 beats/minute, p < 0·01; and 15 beats/minute, p < 0·001), were significantly less than those in the control group (p < 0·05). Further increases in heart rate of 10 and 11 beats/minute were noted at intubation in groups 2 and 3 respectively (significantly less than placebo, p< 0·05).

Although no change in systolic arterial pressure was noted in the control group following induction of anaesthesia and the mean increase after intubation was modest (9·8 mmHg), increases in three patients exceeded 50 mmHg. Arterial pressure was reduced by metoprolol in the period before anaesthesia in groups 2 and 3 by 7·1 mmHg (p< 0·05) and 8·1 mmHg (p < 0·01). Again no changes were noted at induction. Mean increases in blood pressure after intubation did not exceed control levels, and increases of 20–30 mmHg were noted in six patients.

Cardiac rhythm disturbances, of short duration and of no apparent clinical consequence, were noted in association with induction of anaesthesia and intubation. ST segment changes were commonest and occurred in eight patients; five of these were in the placebo group. Six patients had short‐lived ventricular and supraventricular ectopics at induction or intubation of the trachea.
Malignant hyperthermia in a patient with an ankylosed jaw
Authors: JONES SUSAN E.F. , THOMAS COLIN H.
Published: February 2007

Difficult intubation was followed by malignant hyperthermia in a girl with an ankylosedjaw. The treatment, including the use of intravenous dantrolene, is described. The patient's subsequent management, and the anaesthetic implications of these two conditions are discussed.
Anaesthesia in Hong Kong. Its history and present position
Authors: Lett Z.
Published: February 2007

The history of the development of the specialty of anaesthesia in Hong Kong, its present position and future prospects are discussed.

Special reference is made to the activities of the Society of Anaesthetists in Hong Kong which has promoted the cause of anaesthesia and maintained extensive international links during the last 25 years.
Radial artery cannulation Potential hazard in patients with acromegaly
Authors: Campkin T. Victor
Published: February 2007

Using Allen's test, impaired ulnar artery circulation to one or both hands was detected pre‐operatively in five out often acromegalic patients scheduled for transphenoidal hypophysectomy. Three of these patients also had symptoms of compression of the median nerve at the wrist (carpal tunnel syndrome). If ulnar flow is considered to be inadequate cannulation of a dorsalis pedis artery provides one possible alternative route for continuous measurement of the blood pressure during induced hypotension. In the three patients in this report in whom this vessel was cannulated no ischaemic complications in the foot were seen.
Calcium and cardiac arrest
Authors: BULL JOHN , BAND D.M.
Published: February 2007

Various preparations of calcium are recommended for use in treatment of cardiac arrest and advantages are claimed for one preparation over another because of increased availability of the calcium to the heart.

Ionised calcium levels in human blood have been assayed following the addition of calcium increments by use of the calcium electrode. The results showed no difference between calcium chloride and calcium gluconate.
Dental treatment in young handicapped patients
Authors: MANFORD MARGARET L.M. , ROBERTS GRAHAM J.
Published: February 2007

A trial was undertaken to assess the suitability of oxygen/nitrous oxide sedation (relative analgesia) for dental treatment in unmanageable handicapped young patients.

Fifty patients with chronological ages 5–22 years and mental ages 1½–14 years participated in the double blind trial to see if premedication with diazepam 0·2 mg/kg would be a useful adjunct. After the trial, previous dental histories and behaviour at regular recall visits over the next 12–18 months were studied.

Seventeen of 19 patients previously treated with general anaesthesia and 27 of 31 formerly untreated patients accepted treatment in the trial; of the 50 patients, 33 are continuing treatment with oxygen/nitrous oxide sedation, seven need general anaesthesia and 10 have moved from the district. It appears that the use of diazepam premedication improves patient demeanour and operating conditions although this improved effect is not carried over to recall visits.

The results obtained indicate that routine dental procedures can be safely carried out by an experienced operator‐sedationist in young handicapped patients using oxygen/nitrous oxide sedation. The frequency with which potentially hazardous techniques need to be used can be reduced, as can hospital admissions.