Insufficient cerebral perfusion pressure (CPP) after aneurysmal subarachnoid hemorrhage can impair cerebral blood flow. We examined the temporal profiles of CPP change and tested whether these profiles were associated with delayed cerebral ischemia (DCI).CPP values were retrospectively reviewed for 238 subjects. Intracranial pressure and mean arterial pressure values were obtained every 2 hours for 14 days. Induced hypertension was utilized to prevent vasospasm. The linear and quadratic CPP changes over time were tested using growth curve analysis. Multivariable logistic regression was utilized to examine the association between DCI and percentages of CPP values of >110, >100, <70, and <60 mm Hg. DCI was defined as neurological deterioration because of impaired cerebral blood flow.Between-subject differences accounted for 39% of variation in CPP values. There was a significant linear increase in CPP values over time (β = 0.06, SE = 0.006, p < .001). The covariance (-0.52, SE = 0.09, p < .001) between initial CPP and linear parameter was negative, indicating that subjects with high CPP on admission had a slower rate of increase whereas those with low CPP had a faster rate of increase. For every 10% increase in the proportion of CPP of >100 or >110 mm Hg, the odds of DCI increased by 1.21 and 1.43, respectively (p < .05).The longer the time patients spent with high CPP, the greater the odds for DCI. When used prophylactically, induced hypertension contributes to higher CPP values. On the basis of the CPP trends and correlations observed, induced hypertension may not confer expected benefits in patients with aneurysmal subarachnoid hemorrhage.
The use of Braille by individuals who are blind or with visual impairment (VI) is often referred to as default, although the social dynamics of this population is not always intimately entwined with Braille. This study is a quantitative comparison on Braille literacy and auditory literacy to investigate if these two forms of captured information are equivalent to each other. Fifteen college graduates between the ages of 22 and 55 participated in the study: 5 of them were blind or with VI and preferred the use of Braille to access text material; 5 of them were blind or with VI and preferred to process textual material through audition; and 5 of them were individuals without VI and preferred to access textual material through visual print. The results showed that there were no differences among the three groups in their recall of propositions from the texts based upon their preferred method of accessing print (Braille, audition, or print), or in their recall of propositions from the text after having listened to an auditory rendition of an equivalent text. When the scores on the two tasks were compared with each other for individuals, there were no differences for either group of individuals who were blind or with VI, but the group of individuals without VI did better on recalling propositions when they read as opposed to when they listened to the text. Empirical suggestions for a more inclusive definition of literacy are provided to empower individuals with blindness and VI as well as other disabilities.
When polyethylene glycol (PEG)ylated liposomes were repeatedly injected into the same animal, the second dose of liposomes would rapidly clear from the bloodstream and enhance accumulation in the liver and spleen, and this phenomenon is called "accelerated blood clearance (ABC)". There are many factors known to influence ABC phenomenon, in this study, we mainly focused on the effects of different phospholipids (PL) types and animal models. The effects of PL types on ABC phenomenon were examined by repeating injection of PEGylated liposomes prepared by five different types of PL (hydrogenated soy phosphatidylcholine, egg sphingomyelin, soybean phosphatidycholin, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine and egg phosphatidycholin) in rats. Dramatically, repeated injection of different types of PL could induce ABC phenomenon altogether. Both t1/2 and AUC of experimental group (EG) were lower significantly than those of control group (CG). Our results also showed that the liver accumulation of second dose increased significantly (p < 0.01) in all EG as compared that of CG. Interestingly, ABC phenomenon of liposomes prepared by unsaturated PL was more obvious than that of saturated PL. All the first dose could induce the antibody (anti-PEG IgM) level increasing significantly (p < 0.01). For different animal models, we found that after repeated injection of PEGylated liposomes, rats, mice, rabbits and guinea pigs could produce ABC phenomenon. Various PL types and animal models could all produce the ABC phenomenon. However, their extent of accelerated clearance differed. ABC phenomenon is possibly a ubiquitous immune phenomenon in life.
Although young women now obtain higher course grades in math than boys and are just as likely to be enrolled in advanced math courses in high school, females continue to be underrepresented in some Science, Technology, Engineering, and Mathematics (STEM) occupations. This study drew on expectancy-value theory to assess (1) which intellectual and motivational factors in high school predict gender differences in career choices and (2) whether students' motivational beliefs mediated the pathway of gender on STEM career via math achievement by using a national longitudinal sample in the United States. We found that math achievement in 12th grade mediated the association between gender and attainment of a STEM career by the early to mid-thirties. However, math achievement was not the only factor distinguishing gender differences in STEM occupations. Even though math achievement explained career differences between men and women, math task value partially explained the gender differences in STEM career attainment that were attributed to math achievement. The identification of potential factors of women's underrepresentation in STEM will enhance our ability to design intervention programs that are optimally tailored to female needs to impact STEM achievement and occupational choices.
Multilevel structural equation modeling (MSEM) has been proposed as a valuable tool for estimating mediation in multilevel data and has known advantages over traditional multilevel modeling, including conflated and unconflated techniques (CMM & UMM). Recent methodological research has focused on comparing the three methods for 2-1-1 designs, but in regards to 1-1-1 mediation designs, there are significant gaps in the published literature that prevent applied researchers from making educated decisions regarding which model to employ in their own specific research design. A Monte Carlo study was performed to compare MSEM, UMM, and CMM on relative bias, confidence interval coverage, Type I Error, and power in a 1-1-1 model with random slopes under varying data conditions. Recommendations for applied researchers are discussed and an empirical example provides context for the three methods.
Ecological momentary assessment (EMA) methods collect real-time data in real-world environments, which allow physical medicine and rehabilitation researchers to examine objective outcome data and reduces bias from retrospective recall. The statistical analysis of EMA data is directly related to the research question and the temporal design of the study. Hierarchical linear modeling, which accounts for multiple observations from the same participant, is a particularly useful approach to analyzing EMA data. The objective of this paper was to introduce the process of conducting hierarchical linear modeling analyses with EMA data. This is accomplished using exemplars from recent physical medicine and rehabilitation literature.
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