180 research outputs found
Kinetics of CO<sub>2</sub>excretion and intravascular pH disequilibria during carbonic anhydrase inhibition
No full textCardenas, Victor, Jr., Thomas A. Heming, and Akhil Bidani.Kinetics of CO2excretion and intravascular pH disequilibria during carbonic anhydrase inhibition. J. Appl. Physiol. 84(2): 683–694, 1998.—Inhibition of carbonic anhydrase (CA) activity (activity in red blood cells and activity available on capillary endothelium) results in decrements in CO2excretion (V˙co2) and plasma-erythrocyte CO2-[Formula: see text]-H+disequilibrium as blood travels around the circulation. To investigate the kinetics of changes in blood [Formula: see text]and pH during progressive CA inhibition, we used our previously detailed mathematical model of capillary gas exchange to analyze experimental data of V˙co2and blood-gas/pH parameters obtained from anesthetized, paralyzed, and mechanically ventilated dogs after treatment with acetazolamide (Actz, 0–100 mg/kg iv). Arterial and mixed venous blood samples were collected via indwelling femoral and pulmonary arterial catheters, respectively. Cardiac output was measured by thermodilution. End-tidal[Formula: see text], as a measure of alveolar[Formula: see text], was obtained from continuous records of airway [Formula: see text] above the carina. Experimental results were analyzed with the aid of a mathematical model of lung and tissue-gas exchange. Progressive CA inhibition was associated with stepwise increments in the equilibrated mixed venous-alveolar [Formula: see text] gradient (9, 19, and 26 Torr at 5, 20, and 100 mg/kg Actz, respectively). The maximum decrements in V˙co2were 10, 24, and 26% with 5, 20, and 100 mg/kg Actz, respectively, without full recovery ofV˙co2at 1 h postinfusion. Equilibrated arterial [Formula: see text]overestimated alveolar [Formula: see text], and tissue [Formula: see text] was underestimated by the measured equilibrated mixed venous blood[Formula: see text]. Mathematical model computations predicted hysteresis loops of the instantaneous CO2-[Formula: see text]-H+relationship and in vivo blood[Formula: see text]-pH relationship due to the finite reaction times for CO2-[Formula: see text]-H+reactions. The shape of the hysteresis loops was affected by the extent of Actz inhibition of CA in red blood cells and plasma.</jats:p
The Whalley Coucher Book and the dialectal phonology of Lancashire and Cheshire 1175-1350
No full textAn investigation by G. P. Cubbin into the local placename
sources of Lancashire of a time when the vernacular had
a low status isolated the Whalley Coucher Book as the one that
most seemed to deserve further scrutiny. That book therefore
forms the basis of the present study.
The Coucher Boook is a mediaeval work of monastic
provenance and is a compilation of deeds received by Whalley
Abbey over the period. The interest of the source lies in its
representation of many place-names by writers who may be
supposed to have been familiar with them. Whalley's placename
corpus affords scope for examination of variation that is
of dialectal significance.
A searching analysis is undertaken of the evidence
that the Whalley Coucher Book offers. Questions of dating, of
location of place-names, of the elements that compose them,
and of the status of the text have to be examined with a view
to elucidating the significance for phonology of this evidence.
Such examination is carried out at length, and it is hoped that
these aspects of the present work may be found to have
application in linguistic and historical inquiry both for the
actual results relative to the Whalley Coucher Book and for the
methodological demonstration.
A considerable amount of dialectal phonological
information from the source is presented in this thesis. It is
critically examined and collated and the attempt is made to
derive actual usage in the territory and period concerned. On
the whole the conclusion is that most of the evidence does
reflect the dialect and that it produces a believable distribution
of forms.
Some of the dialectal information thus acquired
appears as new. More commonly, however, this study confirms
the existing picture or makes it somewhat more precise. The
evidence does not escape the uneven coverage that is to be
expected in place-name evidence for dialect.
Although the amount of the evidence of the Whalley
Coucher Book and its general consistency are comparatively
good, the finding of this work is that they are not enough to
establish the original suggestion that the Coucher Book might
deserve reliance without reference to, and even in total
defiance of, other local sources. The present study concludes
that the best evidence consists of a select group of sources amongst which Whalley may be taken as pre-eminent
Comparative Difficulties with Non-Scientific General Vocabulary and Scientific/Medical Terminology in English as a Second Language (ESL) Medical Students
No full textObjectives: Medical education requires student comprehension of both technical (scientific/medical) and non-technical (general) vocabulary. Our experience with “English as a second language” (ESL) Arab students suggested they often have problems comprehending scientific statements because of weaknesses in their understanding of non-scientific vocabulary. This study aimed to determine whether ESL students have difficulties with general vocabulary that could hinder their understanding of scientific/medical texts. Methods: A survey containing English text was given to ESL students in the premedical years of an English-medium medical school in an Arabic country. The survey consisted of sample questions from the Medical College Admission Test (USA). Students were instructed to identify all unknown words in the text. Results: ESL students commenced premedical studies with substantial deficiencies in English vocabulary. Students from English-medium secondary schools had a selective deficiency in scientific/medical terminology which disappeared with time. Students from Arabic-medium secondary schools had equal difficulty with general and scientific/medical vocabulary. Deficiencies in both areas diminished with time but remained even after three years of English-medium higher education. Conclusion: Typically, when teaching technical subjects to ESL students, attention is focused on subject-unique vocabulary and associated modifiers. This study highlights that ESL students also face difficulties with the general vocabulary used to construct statements employing technical words. Such students would benefit from increases in general vocabulary knowledge
Creativity and Its Necessity in Teaching and in the Administration of Schools
No full textAs a research exercise, the study of creativity has long been the province of psychologists. In recent y ears, administrators have researched the creativity literature and have encouraged administrative practitioners to accelerate discovery and increase effectiveness of their organizations through more efficient use of their personnel. The author discusses why and how school administrators must manage schools creatively if creativity is to be fostered in the classroom
Using collaborative computing technologies to enable the sharing and integration of simulation services for product design
No full textDamage detection in semiconductor devices by non-linear elastic wave spectroscopy
No full textSemiconductor devices can be found everywhere in our daily lives, for example in self-driving cars, bank cards and personal devices such as smart phones or notebooks. Once part of these personal devices, one does not want them to show failure. Although reliability of such devices is taken into account in the design, the fabrication process might lead to the emergence of small damages in the product. Since these damages or their propagation might cause failure of the device, a series of visual inspections and functional tests is part of the fabrication process. The obtained resolution by optical microscopy, currently the state of the art inspection method, is not sufficient for the detection of small damages such as microcracks or damages located inside a sample. To keep improving the reliability of semiconductor devices, these damages need to be detected in another high speed, low cost way.As semiconductor devices shrink in size, their natural vibration frequencies increase and approach theMHz-range. Vibration based damage detection methods might therefore offer an alternative high speed in-situ inspection method. The main goal of this thesis is to identify and experimentally verify vibration characteristics that indicate the presence of damage, with a focus on microcracks, in semiconductor devices. While linear vibration based damage methods have proven to be insensitive to small damages such as microcracks, non-linear vibration based damage detection methods show much higher sensitivities to this type of damage. The non-linear elastic wave spectroscopy (NEWS) of several damaged materials have shown two characteristic phenomena: amplitude dependent natural frequency shifts and the generation of higher harmonics. Both are explained by a phenomenological non-linear hysteric elastic model. While the applicability of NEWS is proven for several materials, its performance for silicon, in particular at microscale, is still unknown.Mechanical Engineering | Micro and Nano Engineerin
The drama of the forests, romance and adventure, by Arthur Heming; illustrated by the author with reproductions from a series of his paintings owned by the Royal Ontario museum.
No full textxiii, 324 p
A geometric flow on noncompact affine Riemannian manifolds
No full textIn this paper, we obtain the existence criteria for a geometic flow on
noncompact affine Riemannian manifolds. Our results can be regarded as a real
version of Lee-Tam [19]. As an application, we prove that a complete noncompact
Hessian manifold with nonnegative Hessian sectional curvature and bounded
geometry is diffeomorphic to if its tangent bundle has maximal
volume growth.Comment: arXiv admin note: text overlap with arXiv:math/0504422,
arXiv:1708.00141 by other author
Effects of myristate phorbol ester on V-ATPase activity and Na+-H+ exchange in alveolar macrophages
No full textAbstract
The roles of protein kinase G (PKC) in regulation of the plasmalemmal vacuolar-type H+-ATPase (V-ATPase) and Na+-H+ exchanger (NHE) of rabbit alveolar macro phages (mφ) were investigated using phorbol 12-myristate 13-acetate (PMA). At an extracellular pH (pHo) of 7.4 (nominal absence of CO2-HCO- 3), PMA caused a dose-dependent increase in the rate of cellular H+ extrusion with little change in intracellular pH (pHi). PMA caused a prolonged cytosolic acidification at pHo &lt; 6.8. PMA-induced changes in pHi were sensitive to bafilomycin A1, but were insensitive to amiloride. Studies of pHi recovery following intracellular acid challenge showed that both V-ATPase and the NHE were up-regulated by PMA. An inactive analog, 4α-phorbol, had no detectable effects on pHi homeostasis. These data indicate that (a) PKC is involved in regulation of V-ATPase and the NHE of resident alveolar mφ and (b) V-ATPase is the predominant mechanism for pHi homeostasis in unstimulated and PMA-activated mφ. J. Leukoc. Biol. 57: 600–608; 1995.</jats:p
Effects of bafilomycin A1 on functional capabilities of LPS-activated alveolar macrophages
No full textAbstract
Resident alveolar macrophages (mφ) possess plasmalemmal vacuolar-type H+-ATPase (V-ATPase) that plays a crucial role in regulation of intracellular pH (pHi). To assess the importance of this V-ATPase to mφ effector functions, resident alveolar mφ from rabbits were activated with E. coli-derived lipopolysaccharide (LPS) and exposed to bafilomycin A1 a specific inhibitor of V-ATPase. Bafilomycin caused a significant cytosolic acidification in both the absence and presence of CO2-HCO3-, and in both unstimulated and activated mφ. Superoxide production and Fc receptor-mediated phagocytosis also were reduced in bafilomycin-treated mφ. Similar effects were elicited by acidifying the cytoplasm in the absence of bafilomycin, by lowering extracellular pH (pHo) from 7.4 to 6.5–6.6. Thus, the effects of bafilomycin on phagocytosis and superoxide production probably were related to cytosolic acidification, secondary to blockade of V-ATPase-mediated H+ extrusion across the plasma membrane. Conversely, bafilomycin significantly increased TNF-α release. This effect cannot be explained by a bafilomycin-induced acidosis because acidic pHo significantly reduced TNF-α release. The results demonstrate that V-ATPase activity is an important determinant of the effector functions of LPS-activated mφ. J. Leukoc. Biol. 57: 275–281; 1995.</jats:p
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