193 research outputs found
The posterior communicating artery: morphometric study in 3D angio-computed tomography reconstruction. The proof of the mathematical definition of the hypoplasia
Background: The aim of this study was to investigate the morphometry of the posterior communicating artery (PCoA), on the basis of angio-computed tomography (CT), and to give proof of the mathematical definition of the term âhypopal sia of the PCoAâ.Materials and methods: One hundred 3-dimensional (3D) angio-CT images, performed in adult patients with bilateral reconstruction of the PCoA (200 results) were used tocalculate the morphometry of the vessel.Results: The average length of the vessel on the right side was 14.48 ± 3.47 mm, andon the left side 14.98 ± 4.77 mm (in women 14.75 mm, in men 14.70 mm). The mean of the diameter at the âproximalâ point (the junction with P1) on the right side was 1.49 ± 0.51 mm, and on the left 1.46 ± 0.47 mm (in women 1.44 mm and in men 1.51 mm). The mean of the diameter in the âdistalâ part (the connection with ICA) on the right side was 1.4 ± 0.49 mm, and on the left 1.37 ± 0.41 mm (in women 1.38 mm, and in men 1.39 mm). No statistical correlation between the length and the diameter of the PCoA in relation to the sex and side was shown. On the basis of our measurements, we defined the hypoplasia of the artery as the estimated value less than the average diameter minus the standard deviation. The percentage distribution was as follows: the left artery 15.5%, the right artery 24%, women 11.5%, and the men 9%. Similarly to the above parameters, we have not found any statistical differences. The presence of the foetal origin was noted in 25% of the radiological examinations. The infundibular widening was visualised in 11.5% of cases of 3D reconstructions. The agenesis of PCoA was found in 9% (never bilaterally), and in 1 case the unilateral duplication of the artery was observed. No statistical differences between those parameters in relation to sex and the examined side were revealed.Conclusions: Morphological calculation of the PCoA on the basis of angio-CT from adult patients did not show any statistical differences depending on sex or the investigated side. The presented method of the calculations proved to be useful for the mathematical definition of the term âhypoplasia of the PCoAâ
The role of user controls with respect to indoor environmental quality: From evidence to standards
There are important reasons to offer building users the possibility to adjust indoor-environmental conditions. For one thing, people sharing the same indoor environment, may have different needs, requirements, and preferences. The same set of conditions would thus not satisfy everyone. Moreover, even an individual user's preferences can change considerably, given fluctuations in the state of their disposition and health, as well as their physical and cognitive activities. After a brief discussion of available information and evidence concerning the importance of user controls in buildings, the present contribution focuses on the reflection of the user control topic in indoor-environmental quality standards. To this end, a selection of common indoor-environmental quality standards and guidelines is reviewed. The results suggest that, whereas some standards and guidelines refer to user control related issues in a general manner, there is a paucity of more specific guidance in methods and means for incorporation of user control considerations in the building design and operation process
Quantification of endogenous levels of IAA, IAAsp and IBA in micro-propagated shoots of hybrid chestnut pre-treated with IBA
Endogenous levels of indole-3-acetic acid (IAA),
indole-3-acetylaspartic acid (IAAsp) and indole-3-butyric
acid (IBA) were measured during the first 8 d of in vitro
rooting of rootstock from the chestnut âM3â hybrid by high
performance liquid chromatography (HPLC). Rooting was
induced either by dipping the basal ends of the shoots into a
4.92-mM IBA solution for 1 min or by sub-culturing the
shoots on solid rooting medium supplemented with 14.8-
ÎŒM IBA for 5 d. For root development, the induced shoots
were transferred to auxin-free solid medium. Auxins were
measured in the apical and basal parts of the shoots by
means of HPLC. Endogenous levels of IAA and IAAsp
were found to be greater in IBA-treated shoots than in
control shoots. In extracts of the basal parts of the shoots,
the concentration of free IAA showed a significant peak 2 d
after either root inductive method and a subsequent gradual
decrease for the remainder of the time course. The
concentration of IAAsp peaked at day 6 in extracts of the
basal parts of shoots induced with 14.8-ÎŒM IBA for 5 d,
whereas shoots induced by dipping showed an initial
increase until day 2 and then remained stable. In extracts
from basal shoot portions induced by dipping, IBA
concentration showed a transient peak at day 1 and a plateau between day 2 and 4, in contrast to the profile of
shoots induced on auxin-containing medium, which
showed a significant reduction between 4 and 6 d after
transferred to auxin-free medium. All quantified auxins
remained at a relatively low level, virtually constant, in
extracts from apical shoot portions, as well as in extracts
from control non-rooting shoots. In conclusion, the natural
auxin IAA is the signal responsible for root induction,
although it is driven by exogenous IBA independently of
the adding conditions
Uridine Metabolism in the Goldfish Retina During Optic Nerve Regeneration: Cell-Free Preparations
The activities of uridine kinase (EC 2.7.1.48), uridine monophosphate (UMP) kinase (EC 2.7.1.3.14), and uridine diphosphate (UDP) kinase (EC 2.7.4.6) were measured in retinal high-speed supernatant fractions following unilateral optic nerve crush in the goldfish. The enzyme activities followed a similar time course, with initial increases 2-3 days following nerve crush, peak activity at 4 days, and a gradual return to basal levels by day 21. The magnitude of the stimulation on day 4 was about 35% in each case. Activities of two enzymes of intermediary metabolism, pyruvate kinase (EC 2.7.1.40) and lactic dehydrogenase (EC 1.1.1.27), were not altered, indicating that the coordinate increases in nucleoside and nucleotide kinase activities were specific responses to the nerve injury. The increased labeling could not be explained by altered phosphohydrolytic activities. The nature of the enhancement was further studied in UDP kinase, the most active of the kinases examined. Neither low-molecular-weight components nor substrate availability could account for the observed increase in UDP kinase in the 4 day post-crush retinas. The K m , for UDP was unaltered, and a mixing experiment did not support the possibility that stimulatory or inhibitory factors played a role. The enhancement of UDP kinase activity was blocked by injection of actinomycin D following nerve crush. The results suggest that the observed increases in enzymes of uridine metabolism result from their increased formation following nerve crush.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65504/1/j.1471-4159.1981.tb01714.x.pd
Do guidelines influence breathlessness management in advanced lung diseases? A multinational survey of respiratory medicine and palliative care physicians
Background: Respiratory medicine (RM) and palliative care (PC) physiciansâ management of chronic breathlessness in advanced chronic obstructive pulmonary disease (COPD), fibrotic interstitial lung disease (fILD) and lung cancer (LC), and the influence of practice guidelines was explored via an online survey. Methods: A voluntary, online survey was distributed to RM and PC physicians via society newsletter mailing lists. Results: 450 evaluable questionnaires (348 (77%) RM and 102 (23%) PC) were analysed. Significantly more PC physicians indicated routine use (often/always) of opioids across conditions (COPD: 92% vs. 39%, fILD: 83% vs. 36%, LC: 95% vs. 76%; all p < 0.001) and significantly more PC physicians indicated routine use of benzodiazepines for COPD (33% vs. 10%) and fILD (25% vs. 12%) (both p < 0.001). Significantly more RM physicians reported routine use of a breathlessness score (62% vs. 13%, p < 0.001) and prioritised exercise training/rehabilitation for COPD (49% vs. 7%) and fILD (30% vs. 18%) (both p < 0.001). Overall, 40% of all respondents reported reading non-cancer palliative care guidelines (either carefully or looked at them briefly). Respondents who reported reading these guidelines were more likely to: routinely use a breathlessness score (Ï2 = 13.8; p < 0.001), use opioids (Ï2 = 12.58, p < 0.001) and refer to pulmonary rehabilitation (Ï2 = 6.41, p = 0.011) in COPD; use antidepressants (Ï2 = 6.25; p = 0.044) and refer to PC (Ï2 = 5.83; p = 0.016) in fILD; and use a handheld fan in COPD (Ï2 = 8.75, p = 0.003), fILD (Ï2 = 4.85, p = 0.028) and LC (Ï2 = 5.63; p = 0.018). Conclusions: These findings suggest a need for improved dissemination and uptake of jointly developed breathlessness management guidelines in order to encourage appropriate use of existing, evidence-based therapies. The lack of opioid use by RM, and continued benzodiazepine use in PC, suggest that a wider range of acceptable therapies need to be developed and trialled
A Global Building Occupant Behavior Database
This paper introduces a database of 34 field-measured building occupant behavior datasets collected from 15 countries and 39 institutions across 10 climatic zones covering various building types in both commercial and residential sectors. This is a comprehensive global database about building occupant behavior. The database includes occupancy patterns (i.e., presence and people count) and occupant behaviors (i.e., interactions with devices, equipment, and technical systems in buildings). Brick schema models were developed to represent sensor and room metadata information. The database is publicly available, and a website was created for the public to access, query, and download specific datasets or the whole database interactively. The database can help to advance the knowledge and understanding of realistic occupancy patterns and human-building interactions with building systems (e.g., light switching, set-point changes on thermostats, fans on/off, etc.) and envelopes (e.g., window opening/closing). With these more realistic inputs of occupantsâ schedules and their interactions with buildings and systems, building designers, energy modelers, and consultants can improve the accuracy of building energy simulation and building load forecasting
The metabolic significance of octulose phosphates in the photosynthetic carbon reduction cycle in spinach
(14)C-Labelled octulose phosphates were formed during photosynthetic (14)CO(2) fixation and were measured in spinach leaves and chloroplasts. Because mono- and bisphosphates of d-glycero-d-ido-octulose are the active 8-carbon ketosugar intermediates of the L-type pentose pathway, it was proposed that they may also be reactants in a modified CalvinâBensonâBassham pathway reaction scheme. This investigation therefore initially focussed only on the ido-epimer of the octulose phosphates even though (14)C-labelled d-glycero-d-altro-octulose mono- and bisphosphates were also identified in chloroplasts and leaves. (14)CO(2) predominantly labelled positions 5 and 6 of d-glycero-d-ido-octulose 1,8-P(2) consistent with labelling predictions of the modified scheme. The kinetics of (14)CO(2) incorporation into ido-octulose was similar to its incorporation into some traditional intermediates of the path of carbon, while subsequent exposure to (12)CO(2) rapidly displaced the (14)C isotope label from octulose with the same kinetics of label loss as some of the confirmed Calvin pathway intermediates. This is consistent with octulose phosphates having the role of cyclic intermediates rather than synthesized storage products. (Storage products donât rapidly exchange isotopically labelled carbons with unlabelled CO(2).) A spinach chloroplast extract, designated stromal enzyme preparation (SEP), catalysed and was used to measure rates of CO(2) assimilation with Calvin cycle intermediates and octulose and arabinose phosphates. Only pentose (but not arabinose) phosphates and sedoheptulose 7-phosphate supported CO(2) fixation at rates in excess of 120 Όmol h(â1) mg(â1) Chl. Rates for octulose, sedoheptulose and fructose bisphosphates, octulose, hexose and triose monophosphates were all notably less than the above rate and arabinose 5-phosphate was inactive. Altro-octulose phosphates were more active than phosphate esters of the ido-epimer. The modified scheme proposed a specific phosphotransferase and SEP unequivocally catalysed reversible phosphate transfer between sedoheptulose bisphosphate and d-glycero-d-ido-octulose 8-phosphate. It was also initially hypothesized that arabinose 5-phosphate, an L-Type pentose pathway reactant, may have a role in a modified Calvin pathway. Arabinose 5-phosphate is present in spinach chloroplasts and leaves. Radiochromatography showed that (14)C-arabinose 5-phosphate with SEP, but only in the presence of an excess of unlabelled ribose 5-phosphate, lightly labelled ribulose 5-phosphate and more heavily labelled hexose and sedoheptulose mono- and bisphosphates. However, failure to demonstrate any CO(2) fixation by arabinose 5-phosphate as sole substrate suggested that the above labelling may have no metabolic significance. Despite this arabinose and ribose 5-phosphates are shown to exhibit active roles as enzyme co-factors in transaldolase and aldolase exchange reactions that catalyse the epimeric interconversions of the phosphate esters of ido- and altro-octulose. Arabinose 5-phosphate is presented as playing this role in a New Reaction Scheme for the path of carbon, where it is concluded that slow reacting ido-octulose 1,8 bisphosphate has no role. The more reactive altro-octulose phosphates, which are independent of the need for phosphotransferase processing, are presented as intermediates in the new scheme. Moreover, using the estimates of phosphotransferase activity with altro-octulose monophosphate as substrate allowed calculation of the contributions of the new scheme, that ranged from 11% based on the intact chloroplast carboxylation rate to 80% using the carboxylation rate required for the support of octulose phosphate synthesis and its role in the phosphotransferase reaction
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