365 research outputs found
The impact of pregnancy on peak flow values in women with asthma
No full textAsthma is the most common respiratory complication of pregnancy and affects approximately four per cent of all pregnant women. The purpose of this study was to establish normative data regarding how peak flow values change during gestation in pregnant women with asthma. Eighteen pregnant women with asthma were recruited and completed dally logs throughout their pregnancies. The findings suggest there is a difference in peak flow values in different trimesters. Specifically peak flow values were highest in the second trimester with significant differences between the second and third trimesters. While the sample size is small it does provide longitudinal data that suggest changes in asthma as the pregnancy progresses. This study represents a logical next step in identifying the impact of pregnancy on asthma.Peer reviewe
Peak Flow Values by Gestation in Women with Asthma
No full textAsthma is one of the most common medical complications of pregnancy. Control of asthma is associated with improved perinatal outcomes compared with pregnancies of women whose asthma is not controlled. Peak flow measures have been recommended to determine the status of asthma yet norms for peak flow values in women with asthma are missing from the literature. The purpose of this prospective, longitudinal study was to determine average peak flow values in pregnant women with asthma. Forty three women were recruited into the study prior to the twentieth week of pregnancy. Demographic data including age, ethnic background, and number of pregnancies were collected. Type and severity of asthma, medications used for asthma, and past hospitalizations for asthma was recorded. Peak flow values increased across the three trimesters. Significant differences were found in peak flow values between the first and third trimesters (>0.001) and the second and third trimesters (>0.007). Findings from the present study contradict those of studies on pregnant women without asthma. Since hormonal levels change during pregnancy and hormones are thought to influence the status of asthma, the interaction of hormonal changes of pregnancy and asthma warrant further study.Peer reviewe
Synthesis and structures of 3,5-disubstituted 1,2,4-triazole head units and incorporation of 3,5-dibenzoyl-1,2,4-triazolate into new [2 + 2] Schiff-base macrocyclic complexes
No full textThe synthesis and characterization of sodium 3,5-diacetyl- 1,2,4- triazolate (4 (Me)) and sodium 3,5-dibenzoyl-1,2,4- triazolate (4 (Ph)), both of which can be used as head unit building blocks in Schiff-base reactions, are reported. The crystal structures of sodium 3,5-diacetyl-1,2,4- triazolate, as [4 (Me)(H2O)]infinity, and sodium 3,5-dibenzoyl-1,2,4- triazolate, as [4 (Ph)(CH3OH)(2] 2), have been determined. The former is a helical polymer whilst the latter is a methanol-bridged dimer. The lead(II) templated cyclization reaction of sodium 3,5-dibenzoyl-1,2,4-triazolate (4 (Ph)) with 1,3-diaminopropane or 1,4-diaminobutane, respectively, leads to the formation of two new [ 2 + 2] Schiff-base macrocycles as their lead(II) complexes, [Pb2L (3Ph)(mu-OH)]ClO4 (5) and [Pb2L (4Ph)(mu-OH)] ClO4 ( 6), respectively. Transmetallation of 5 with nickel(II) ions yields a novel, structurally characterized, dinickel(II) macrocyclic complex, [Ni2L (3Ph)(NCS)(2)] ( 7), which features double triazolate bridging of the two five-coordinate nickel(II) ions
The Role of Coordination and Cooperation for Bt-maize cultivation in Brandenburg, Germany
No full textSince 2006, several varieties of transgenic Bt-maize are approved for commercial cultivation in Germany. The German regulatory framework for growing these crops comprises ex-ante regulations as well as ex-post liability rules to protect conventional and organic farming from possible negative side effects of transgenic plants and to ensure co-existence. Public regulation is also suspected to impose additional costs to those farmers who intend to plant Bt-maize. We address the question how Bt-maize growing farmers perceive the additional costs of regulation and whether coordination or cooperation takes place in order to diminish these costs. In 2006, we carried out a case study in the Oderbruch region (Brandenburg, Germany) comprising eight Bt-maize growing farmers and six adjacent neighbours. The predominantly large farms chose intrafarm coordination to manage the construction of buffer zones within their own fields and to avoid the planting of Bt-maize close to their neighbours. Inter-farm coordination or cooperation with adjacent farmers was not regarded necessary to achieve co-existence.Coordination, Cooperation, Bt-maize, Crop Production/Industries,
Faculty Perception of Bullying in Schools of Nursing
No full textAims: This paper is a report of a study of conducted to determine the prevalence of bullying among faculty members in Schools or Colleges of Nursing.
Background: The issue of bullying of nursing faculty in the academic setting is of interest in terms of recruitment, retention, job satisfaction, and the overall quality of the work environment.
Method: This cross-sectional, descriptive study of faculty in three northeastern states of the U.S. was carried out in 2010. The Negative Acts Questionnaire-Revised was used to survey faculty members in Schools of Nursing who award a baccalaureate degree (or higher) in nursing.
Results: 473 faculty members met the inclusion criteria and responded to the NAQ-R. An iterative exploratory principal components analysis with orthogonal rotation was performed. Thirteen of the original 22 items were retained to measure the experiences of negative acts in the nursing faculty workplaces. The mean total score for the 13 item instrument was 17.90 (SD 6.07) and ranged from 13 to 56. The resulting components structure produced three clear subscales identifying the experiences of: Verbal abuse, Physical abuse, and Devaluing. The revised 13 item instrument had a Cronbach’s alpha value of 0.88. Experiences of bullying were reported in 169 of the 473 (36%) respondents. A significant correlation was found between meeting frequency and the report of bullying (r = 0.18, p ≤ 0.001). Administrators and senior faculty were more likely than expected to be the perpetrators of bullying.
Discussion: If the leaders are identified as bullies, the environment cannot be perceived as supportive and healthy. These unhealthy environments may have serious consequences related to retaining nursing faculty.Peer reviewe
A dance or a marriage? The relationship between education and the law in South Africa some personal observations from two vantage points
No full textThis article deals with the debate in education and law circles about the convergence of the two fields of knowledge in an area conveniently called education law. It recognises that there is no universal acknowledgement of the existence of such a discipline.
Although the article does not present a full scale analysis of the relationship between education and law, it does present some views emerging from the existence and functioning of two organisations in South Africa namely the South African Education Law Association (SAELA) and the Interuniversity Centre for Education Law and Policy (CELP). Both of the organisations aim to promote education law research and training. In light of the existing literature the relationship is likened to a marriage of convenience or a dance in which the quality of the relationship between the two fields varies.
The author examines and concurs with opinions that there are grounds to support the notion that a discrete field of inquiry named education law does exist in South Africa. However, the relationship still needs to be developed for the field to mature as an academic discipline. Among the problems that have to be addressed are the lack of interest in universities (especially law faculties at former English universities) in this field, the subsequent imbalance between educators and jurists active in the field and the failure of educational administrators to abide by the law even if they are aware of what the law requires. Added to this failure is a lack of knowledge among administrators of education law and the presence of a phenomenon termed the use of imagined power among them.
The article concludes that there are indications that the relationship between education and the law can lead to the development and promotion of a discrete field of law named education law
An experimental analysis of the transport of drilled particles in an annulus
No full textLaboratory tests were carried out to study the removal of drilled particles in a well borehole simulated annulus. The main objectives of these tests were to determine the effect of varying: (1) the particle size and particle size distribution; (2) the annular flow rate; (3) the fluid type viscosity and density; (4) the rate of rotation of the inner pipe. Dropping tests with individual particles of various sizes were also performed to study the behavior of, and to determine the settling velocity of these particles in a quiescent Newtonian fluid medium of varying viscosity. From these experiments a general settling velocity equation applicable to all particle sizes and an expression for the cumulative mass fraction of particles removed from the annulus are formulated. It was concluded that: (1) Under a given constant state, the total mass fraction of particles removed may be less than one. (2) At low annular flow rates, the first arrival time, (tmin)ap, for any one particle size may be greater than the minimum time based on the relative average fluid and single particle settling velocities. (3) The initial number of particles of any one particular particle size affects fcmax and (tmin)ap. (4) Rotating the inner pipe does increase the rate at which particles are removed and the total number of particles removed. (5) Introducing a drilling mud into the annulus may or may not increase the rate at which particles are removed, compared to the same annular flow rates using water. The exact behavior of the particles under these conditions was not determined, and the reduction of Reynolds number from turbulent to laminar flow by use of the drilling muds does not permit a true comparison between water and drilling muds. (6) In the laminar flow of drilling muds, it appears that one must consider both the relative flatness of velocity profiles and the particle Reynolds number in evaluating the carrying capacity capabilities of these fluids. A flatter velocity profile (low power law exponent) alone does not necessarily insure better carrying capacity
Intrauterine Wachstumsrestriktion und Präeklampsie: Kein Hinweis auf Aktivierung der plazentaren Stressreaktion des endoplasmatischen Retikulums in zwei Nagetiermodellen
No full textObjectives:
The pregnancy complications preeclampsia (PE) and intrauterine growth restriction (IUGR) are among the leading causes of fetal and maternal morbidity and mortality. While both conditions share some pathophysiological features leading to placental dysfunction, the exact underlying pathomechanisms remain largely unclear. Therefore, only limited therapeutic options for PE and IUGR exist. In humans, PE/IUGR are associated with induction of the unfolded protein response (UPR). The UPR is a stress response of the endoplasmic reticulum (ER) consisting of several signalling cascades to adapt to altered homeostatic conditions. Especially in PE, additional oxidative stress occurs relative to the severity of maternal vascular underperfusion of the placental bed. On the premise that understanding the mechanisms of placental dysfunction could lead to targeted therapeutic options for human PE/IUGR, the present doctoral thesis investigated the roles of placental UPR and oxidative stress in two rodent models of these human gestational pathologies.
Study design & Methods:
The following animal models were employed: 1) A PE and IUGR mouse model (PE/IUGR) with gene knockout of endothelial nitric oxide synthase (eNOS-/-) in which wild type (WT) C57BL/6 mice served as controls; 2) An established IUGR rat model of maternal protein restriction in which pregnant dams were fed a low protein diet (8 % protein content, LP, IUGR group) or standard diet (17 % protein content, NP, control group). Placental samples of both models were obtained at E18.5 and additionally at an earlier gestational stage (E15) in the mouse model. While placental tissues of both sexes were examined in the rat model, only placentas of male fetuses were accessible for analysis in the mouse. Placental expression of UPR members (Grp78, Calnexin, Perk, Chop, Atf6, Ern1) was analyzed via real-time polymerase chain reaction (RT-PCR) and western blotting (Calnexin, ATF6, GRP78, CHOP, phospho-eIF2α, phospho-IRE1). Immunohistochemistry (IHC) was performed to characterize the localization of these ER stress markers in functional compartments of healthy placenta and their potential alteration in association with PE and IUGR. The presence of oxidative stress was determined via western blot measurement of placental 3-nitrotyrosine in both animal models. In PE/IUGR eNOS-/--mice, 4-hydroxy-2-nonenal (HNE) was additionally determined.
Observations & Results:
The offspring of both animal models showed a significant induction of IUGR characterized by a significant reduction of fetal and placental weight. However, in contrast to human data placental activation of the UPR signaling cascades could not be detected. IHC showed no alteration in the localization of UPR signalling proteins under adverse intrauterine conditions in both models. Placental oxidative stress was significantly increased in female IUGR rats only. No such change was found in the placentas of male IUGR rats and PE/IUGR mice.
Conclusions:
In contrast to findings of increased placental ER stress in human PE and IUGR, the results of the rodent PE/IUGR and IUGR models did not demonstrate a significant increase in placental UPR. Therefore, it can be assumed that the placenta retains compensatory capacity, enabling the adaptation to the adverse gestational conditions in these rodent models. The exact mechanisms underlying this placental plasticity remain to be further elucidated. The induction of oxidative stress without concomitant UPR activation in the placenta of the female IUGR rats further supports this hypothesis and indicates a sexually dimorphic response to maternal malnutrition. Based on the absence of placental UPR in consideration of retained placental plasticity, the examined rodent models seem to be of limited use for studies regarding the role of placental ER stress in human gestational disorders.Hintergrund und Ziele:
Die beiden Schwangerschaftskomplikationen Präeklampsie (PE) und intrauterine Wachstumsrestriktion (IUGR) zählen zu den führenden Ursachen für fetale und maternale Morbidität und Mortalität. Bei beiden Pathologien nimmt die plazentare Dysfunktion eine zentrale Stellung in der Pathophysiologie ein, jedoch sind die Details der zugrunde liegenden Pathomechanismen noch weitgehend unbekannt. Infolgedessen existiert bislang nur ein limitiertes Spektrum an Therapieoptionen für PE und IUGR. Verschiedene humane Studien suggerieren einen Zusammenhang zwischen PE/IUGR und der Induktion der plazentaren Unfolded Protein Reponse (UPR). Bei der UPR handelt es sich um eine Stressreaktion des endoplasmatischen Retikulums (ER) auf veränderte homöostatische Bedingungen in der Zelle, die sich aus mehreren überlappenden Signalkaskaden zusammensetzt. Insbesondere bei der PE kommt es in Abhängigkeit vom Schweregrad der maternalen vaskulären Malperfusion des Plazentabettes neben der ER-Stressantwort zu zusätzlichem oxidativem Stress. Die Identifizierung zugrunde liegender Pathomechanismen der plazentaren Dysfunktion bei PE/IUGR könnte langfristig zur Etablierung von Präventions- und/oder Interventionsmöglichkeiten führen, weswegen in dieser Publikationsdissertation die Rolle der UPR und des oxidativen Stresses in den Plazenten von zwei Nagetiermodellen dieser Schwangerschaftspathologien analysiert wird.
Methoden:
Die folgenden Tiermodelle kamen zum Einsatz: 1) Ein PE und IUGR-Mausmodell (PE/IUGR) mit einem Genknockout der endothelialen Stickstoffmonoxid-Synthase (eNOS-/-), wobei Wildtyp (WT) C57BL/6 Mäuse als Kontrollen dienten. 2) Ein etabliertes IUGR-Rattenmodell der maternalen Proteinrestriktion, bei dem trächtigen Muttertieren eine Niedrigproteindiät (8 % Proteingehalt, LP, IUGR-Gruppe) oder Standardfutter (17 % Proteingehalt, NP, Kontrollgruppe) zugeführt wurde. Plazentaproben beider Modelle wurden am Gestationstag E18.5 gewonnen und zusätzlich an einem früheren Gestationstag (E15) im Mausmodell. Während im Rattenmodell Plazentagewebe beider Geschlechter untersucht wurde, waren im Mausmodell nur Plazenten männlicher Feten für die Analyse zugänglich. Die plazentare Expression von ER-Stressmarkern (Grp78, Calnexin, Perk, Chop, Atf6, Ern1) wurde mittels Real-Time Polymerasekettenreaktion (RT-PCR) und Western Blot (Calnexin, ATF6, GRP78, CHOP, phospho-eIF2α, phospho-IRE1) analysiert. Die Immunhistochemie (IHC) wurde genutzt, um die Lokalisierung dieser ER-Stressmarker in den funktionellen Kompartimenten der gesunden Plazenta sowie deren potenzielle Alteration im Zusammenhang mit PE und IUGR zu charakterisieren. Oxidativer Stress wurde durch Western Blot Messungen von plazentarem 3-Nitrotyrosin im IUGR-Rattenmodell sowie zusätzlich von 4-Hydroxy-2-nonenal (HNE) im PE/IUGR eNOS-Knockout-Mausmodell bestimmt.
Ergebnisse und Beobachtungen:
Die Nachkommen beider Tiermodelle zeigten eine signifikante Induktion einer IUGR, die durch eine signifikante Reduktion des fetalen und plazentaren Gewichts gekennzeichnet war. Im Gegensatz zur humanen Datenlage konnte jedoch keine plazentare Aktivierung der UPR-Signalkaskaden nachgewiesen werden. Die IHC zeigte keine Veränderung in der Lokalisation der UPR-Signalproteine unter den ungünstigen intrauterinen Bedingungen in beiden Modellen. Eine signifikante Erhöhung des plazentaren oxidativen Stresses zeigte sich nur bei weiblichen IUGR-Ratten, wohingegen kein Anstieg in den Plazenten von männlichen IUGR-Ratten und PE/IUGR-Mäusen gemessen wurde.
Schlussfolgerungen:
Im Gegensatz zu den Beobachtungen einer erhöhten ER-Stressantwort bei humaner PE und IUGR, zeigten die untersuchten Nagetiermodelle keine signifikante Erhöhung der plazentaren UPR-Aktivierung. Daraus lässt sich folgern, dass die Plazenta über eine kompensatorische Kapazität verfügt, welche die Anpassung an die veränderten Gestationsbedingungen in diesen Nagetiermodellen ermöglicht. Die genauen Mechanismen, die dieser plazentaren Plastizität zugrunde liegen, bedürfen jedoch noch weiterer Aufklärung. Das erhöhte oxidative Stresslevel ohne eine begleitende UPR-Aktivierung in der Plazenta der weiblichen IUGR-Ratten untermauert diese Hypothese und deutet auf eine geschlechtsspezifische plazentare Reaktion auf maternale Malnutrition hin. Aufgrund des fehlenden Nachweises einer UPR-Aktivierung in Anbetracht der erhaltenen plazentaren Plastizität, scheinen die untersuchten Nagetiermodelle von begrenztem Nutzen für weitere Untersuchungen der Rolle des plazentaren ER-Stresses bei humanen Schwangerschaftskomplikationen zu sein.
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