scholarly journals Effects of nitrogen and helium on CNS oxygen toxicity in the rat

2005 ◽  
Vol 98 (1) ◽  
pp. 144-150 ◽  
Author(s):  
R. Arieli ◽  
O. Ertracht ◽  
I. Oster ◽  
A. Vitenstein ◽  
Y. Adir

The contribution of inert gases to the risk of central nervous system (CNS) oxygen toxicity is a matter of controversy. Therefore, diving regulations apply strict rules regarding permissible oxygen pressures (Po2). We studied the effects of nitrogen and helium (0, 15, 25, 40, 50, and 60%) and different levels of Po2 (507, 557, 608, and 658 kPa) on the latency to the first electrical discharge (FED) in the EEG in rats, with repeated measurements in each animal. Latency as a function of the nitrogen pressure was not homogeneous for each rat. The prolongation of latency observed in some rats at certain nitrogen pressures, mostly in the range 100 to 500 kPa, was superimposed on the general trend for a reduction in latency as nitrogen pressure increased. This pattern was an individual trait. In contrast with nitrogen, no prolongation of latency to CNS oxygen toxicity was observed with helium, where an increase in helium pressure caused a reduction in latency. This bimodal response and the variation in the response between rats, together with a possible effect of ambient temperature on metabolic rate, may explain the conflicting findings reported in the literature. The difference between the two inert gases may be related to the difference in the narcotic effect of nitrogen. Proof through further research of a correlation between individual sensitivity to nitrogen narcosis and protection by N2 against CNS oxygen toxicity in rat may lead to a personal O2 limit in mixed-gas diving based on the diver sensitivity to N2 narcosis.

Methodology ◽  
2006 ◽  
Vol 2 (4) ◽  
pp. 142-148 ◽  
Author(s):  
Pere J. Ferrando

In the IRT person-fluctuation model, the individual trait levels fluctuate within a single test administration whereas the items have fixed locations. This article studies the relations between the person and item parameters of this model and two central properties of item and test scores: temporal stability and external validity. For temporal stability, formulas are derived for predicting and interpreting item response changes in a test-retest situation on the basis of the individual fluctuations. As for validity, formulas are derived for obtaining disattenuated estimates and for predicting changes in validity in groups with different levels of fluctuation. These latter formulas are related to previous research in the person-fit domain. The results obtained and the relations discussed are illustrated with an empirical example.


1975 ◽  
Vol 34 (02) ◽  
pp. 426-444 ◽  
Author(s):  
J Kahan ◽  
I Nohén

SummaryIn 4 collaborative trials, involving a varying number of hospital laboratories in the Stockholm area, the coagulation activity of different test materials was estimated with the one-stage prothrombin tests routinely used in the laboratories, viz. Normotest, Simplastin-A and Thrombotest. The test materials included different batches of a lyophilized reference plasma, deep-frozen specimens of diluted and undiluted normal plasmas, and fresh and deep-frozen specimens from patients on long-term oral anticoagulant therapy.Although a close relationship was found between different methods, Simplastin-A gave consistently lower values than Normotest, the difference being proportional to the estimated activity. The discrepancy was of about the same magnitude on all the test materials, and was probably due to a divergence between the manufacturers’ procedures used to set “normal percentage activity”, as well as to a varying ratio of measured activity to plasma concentration. The extent of discrepancy may vary with the batch-to-batch variation of thromboplastin reagents.The close agreement between results obtained on different test materials suggests that the investigated reference plasma could be used to calibrate the examined thromboplastin reagents, and to compare the degree of hypocoagulability estimated by the examined PIVKA-insensitive thromboplastin reagents.The assigned coagulation activity of different batches of the reference plasma agreed closely with experimentally obtained values. The stability of supplied batches was satisfactory as judged from the reproducibility of repeated measurements. The variability of test procedures was approximately the same on different test materials.


Author(s):  
Daniel Stark ◽  
Stefania Di Gangi ◽  
Caio Victor Sousa ◽  
Pantelis Nikolaidis ◽  
Beat Knechtle

Though there are exhaustive data about participation, performance trends, and sex differences in performance in different running disciplines and races, no study has analyzed these trends in stair climbing and tower running. The aim of the present study was therefore to investigate these trends in tower running. The data, consisting of 28,203 observations from 24,007 climbers between 2014 and 2019, were analyzed. The effects of sex and age, together with the tower characteristics (i.e., stairs and floors), were examined through a multivariable statistical model with random effects on intercept, at climber’s level, accounting for repeated measurements. Men were faster than women in each age group (p < 0.001 for ages ≤69 years, p = 0.003 for ages > 69 years), and the difference in performance stayed around 0.20 km/h, with a minimum of 0.17 at the oldest age. However, women were able to outperform men in specific situations: (i) in smaller buildings (<600 stairs), for ages between 30 and 59 years and >69 years; (ii) in higher buildings (>2200 stairs), for age groups <20 years and 60–69 years; and (iii) in buildings with 1600–2200 stairs, for ages >69 years. In summary, men were faster than women in this specific running discipline; however, women were able to outperform men in very specific situations (i.e., specific age groups and specific numbers of stairs).


2021 ◽  
Vol 11 (10) ◽  
pp. 4589
Author(s):  
Ivan Duvnjak ◽  
Domagoj Damjanović ◽  
Marko Bartolac ◽  
Ana Skender

The main principle of vibration-based damage detection in structures is to interpret the changes in dynamic properties of the structure as indicators of damage. In this study, the mode shape damage index (MSDI) method was used to identify discrete damages in plate-like structures. This damage index is based on the difference between modified modal displacements in the undamaged and damaged state of the structure. In order to assess the advantages and limitations of the proposed algorithm, we performed experimental modal analysis on a reinforced concrete (RC) plate under 10 different damage cases. The MSDI values were calculated through considering single and/or multiple damage locations, different levels of damage, and boundary conditions. The experimental results confirmed that the MSDI method can be used to detect the existence of damage, identify single and/or multiple damage locations, and estimate damage severity in the case of single discrete damage.


2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
R Bosco ◽  
S Gambelli ◽  
V Urbano ◽  
G Cevenini ◽  
G Messina

Abstract Background Sanitizing the operating theatres (OT) is important to minimize risk of post-operative infections. Disinfection procedures between one operation and another is less aggressive than final cleaning procedures, at the end of the day. Aim was assessing the difference of contamination: i) between different levels of disinfection; ii) before and after the use of a UVC Device (UVC-D). Methods Between December 2019/February 2020 a cross sectional study was conducted in OT in a real clinical context. 94 Petri dishes (PD) were used in 3 OT. Three different sanitation levels (SL1-3) were compared pre- and post-use of UVC-D: i) No cleaning after surgery (SL1); ii) after in-between cleaning (SL2); iii) after terminal cleaning (SL3). UVC-D was employed for 6 minutes, 3 minutes per bed side. PD were incubated at 36 °C and colony forming unit (CFU) counted at 48h. Descriptive statistic, Wilcoxon and Mann-Whitney tests were performed to assess the contamination levels in total, pre/post use of UVC-D, and between different sanitation levels, respectively. Results In total we had a mean of 3.39 CFU/PD (C.I. 2.05 - 4.74) and a median of 1 CFU/PD (Min. 0 - Max. 39), after UVC-D use we had a mean of 2.20 CFU/PD (C.I. 0.69 - 5.09) and a median of 0 CFU/PD (Min. 0 - Max. 133). The UVC-D led to a significant reduction of CFU (p &lt; 0.001). Without UVC-D we had a significant CFU drop (p &lt; 0.05) between SL1 and SL3. Using UVC-D, we observed significant reductions of contamination (p &lt; 0.05) between SL3 and SL1. Comparing SL1 (median 0) post UVC-D use vs SL2 pre UVC-D use (median 0.5), and SL2 post UVC-D use (median 0) vs SL3 pre UVC-D use (median 1) we had a significant reduction of contamination (p &lt; 0.05). Conclusions UVC-D improved environmental contamination in any of the three sanitation levels. Furthermore, the use of UVC-D alone was better than in-between and terminal cleaning. Although these encouraging results, the cleaning procedures executed by dedicated staff has to be considered. Key messages UVC are efficient to decrease contamination in operating theatres regardless of sanitation levels. The additional use of UVC technology to standard cleaning procedures significantly improves sanitation levels.


2021 ◽  
Vol 7 (1) ◽  
pp. 331-341
Author(s):  
Urszula Chwesiuk

Abstract The aim of this study was an attempt to verify whether Polish speakers of English insert a vowel in the word-final clusters containing a consonant and a syllabic /l/ or /n/ due to the L1–L2 transfer. L1 Polish speakers are mostly unaware of the existence of syllabic consonants; hence, they use the Polish phonotactics and articulate a vocalic sound before a final sonorant which is deprived of its syllabicity. This phenomenon was examined among L1 Polish speakers, 1-year students of English studies, and the recording sessions were repeated a year later. Since, over that time, they were instructed with regard to phonetics and phonology but also the overall practical language learning, the results demonstrated the occurrence of the phenomenon of vowel insertion on different levels of advanced command of English. If the vowels were inserted, their quality and length were monitored and analysed. With regard to the English system, pronouncing vowel /ə/ before a syllabic consonant is possible, yet not usual. That is why another aim of this study is to examine to what extent the vowels articulated by the subjects differ from the standard pronunciation of non-final /ə/. The quality differences between the vowels articulated in the words ending with /l/ and /n/ were examined as well as the potential influence from the difference between /l/ and /n/ on the occurrence of vowel reduction. Even though Polish phonotactics permit numerous consonantal combinations in all word positions, it proved to be challenging for L1 Polish speakers to pronounce word-final consonantal clusters containing both syllabic sonorants. This result carries practical implications for the teaching methodology of English phonetics.


De Jure ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Daniel Haman ◽  
◽  
◽  

The difference between intent (dolus) and negligence (culpa) was rarely emphasized in codified medieval laws and regulations. When compared to the legal statements related to intent, negligence was mentioned even more rarely. However, there are some laws that distinguished between the two concepts in terms of some specific crimes, such as arson. This paper draws attention to three medieval Slavic legal documents – the Zakon Sudnyj LJudem (ZSLJ), the Vinodol Law and the Statute of Senj. They are compared with reference to regulations regarding arson, with the focus being on arson as a crime committed intentionally or out of negligence. The ZSLJ as the oldest known Slavic law in the world shows some similarities with other medieval Slavic legal codes, especially in the field of criminal law, since most of the ZSLJ’s articles are related to criminal law. On the other hand, the Vinodol Law is the oldest preserved Croatian law and it is among the oldest Slavic codes in the world. It was written in 1288 in the Croatian Glagolitic script and in the Croatian Chakavian dialect. The third document – the Statute of Senj – regulated legal matters in the Croatian littoral town of Senj. It was written in 1388 – exactly a century after the Vinodol Law was proclaimed. When comparing the Vinodol Law and the Statute of Senj with the Zakon Sudnyj LJudem, there are clear differences and similarities, particularly in the field of criminal law. Within the framework of criminal offenses, the act of arson is important for making a distinction between intent and negligence. While the ZSLJ regulates different levels of guilt, the Vinodol Law makes no difference between dolus and culpa. On the other hand, the Statute of Senj strictly refers to negligence as a punishable crime. Even though the ZSLJ is almost half a millennium older than the Statute of Senj and around 400 years older than the Vinodol Law, this paper proves that the ZSLJ defines the guilt and the punishment for arson much better than the other two laws.


2019 ◽  
Vol 3 (2) ◽  
pp. 447-461
Author(s):  
Ardina Fahriyanti Maharani ◽  
Erlina Prihatnani

In solid geometry needed the ability to visualize space that cannot be seen so differences in visual intelligence can trigger errors in solving geometry problems. Therefore, this study aimed to determine the types of errors made by students and the factors that cause errors in working on geometry problems based on Newman's Error Analysis (NEA) in terms of visual intelligence. This research chose the subjects of class XII high school who had studied the material distance points to lines in space with different levels of visual intelligence, namely high and low. The process of collecting data used visual intelligence test questions, geometry test questions, and interviews. The results of this study indicated that the level of students' visual intelligence affects the difference in location and the factor that causes errors in the stage of transformation especially on determining the distance in dimension 3. Students with high visual intelligence made mistakes at the stage of transformation and encoding that caused by the students’ carelessness. However, students with low visual intelligence made mistakes at the stage of comprehension, transformation, process skills, and encoding due to the concept of the point distance to the line and the concept of the Pythagorean theorem.


Author(s):  
Armstrong O. Njok ◽  
Julie C. Ogbulezie ◽  
Manoj Kumar Panjwani ◽  
Raja Masood Larik

<p>The effect of time of day and month on the efficient conversion of solar energy to electrical energy using a polycrystalline (PV) module in calabar was studied. A KT-908 precision digital hygrometer and thermometer, and a M890C+ digital multimeter were used in the process. Results obtained shows that photovoltaic produce different levels of peak efficiencies at different times of the day for different months due to the difference in sunrise and sunset times for the months. The results also indicated that photovoltaics will be more efficient in months with low average relative humidity couple with low panel temperature. A peak efficiency of 77% at 12:30 in the month of April was observed before dropping to 73% at 12:00 in the month of May, indicating that there might be further drop in efficiency as we proceed further into the year. Results also show that photovoltaics are more efficient before noon in the month of May than in April while the reverse will be observed in the afternoon. </p>


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