The effect of resting and compression time post-centrifugation on the characteristics of platelet rich fibrin (PRF) membranes.

OBJECTIVE: To evaluate the effect of resting and compression time after centrifugation on the physical properties of platelet rich fibrin (PRF) membranes, and to provide optimal guidance regarding the clinical preparation of PRF. MATERIALS AND METHODS: A total of 12 volunteers enrolled in this study divided into 2 groups equally. For each volunteer, 6 tubes of 10 mL venous whole blood was drawn. To evaluate the influence of resting time after centrifugation, PRF clots were taken out 0, 1, 3, 5, 7, and 10 min from tubes following centrifugation, and then the weight, size, maximum stress, and maximum strain of each group were measured. To evaluate the influence of compression time on the preparation of PRF membranes, the weight ratio of PRF membranes to PRF clots was calculated by compression for 10 s, 30 s, 60 s, 90 s, 120 s, and 180 s, respectively. Scanning electron microscopy was performed to observe the cross-linking of the fibers within membranes, and the maximum stress and strain of PRF membranes were tested followed by stress-strain curve analysis. RESULTS: The weight and volume of PRF clots and PRF membranes increased in size and weight reached the top at 3 min, followed by a decrease after 7-min resting. The maximum strain of the PRF membranes after 10 min decreased significantly compared to the 3-min and 5-min groups. The maximum stress was found at 3 min followed by a statistical decrease when resting time went on. Scanning electron microscopy demonstrated that the internal fibrous structure of the PRF membranes was looser when the compression time was less than 60 s when comparing the 90-s group. The maximum stress of PRF membranes was shown using a wait period of 3 min post-centrifugation followed by compression for 120 s. CONCLUSION: The findings from the present study demonstrate that the time post-centrifugation of PRF membranes showed a maximum weight, volume, and mechanical properties after resting for 3-5 min in the tube post-centrifugation followed by a compression time of 120 s. CLINICAL RELEVANCE: Although research to date has focused primarily on centrifugation protocols, this study revealed for the first time that the resting time post-centrifugation greatly affected the mechanical properties of PRF. This study demonstrated that the resting and compression time after centrifugation influences the mechanical strength of PRF membranes, which might explain differences in PRF characteristics prepared by different clinicians that may provide a standard guide for preparation of PRF membranes.

Facial skin physiology recovery kinetics during 180 min post-washing with a cleanser.

BACKGROUND/PURPOSE: Facial cleansing is important to clean and exfoliate the skin while maintaining optimal physiologic function. However, there is insufficient data on the very early stage of skin change after applying soap or cleansing foam. We investigated the recovery kinetics of facial skin physiology during 180 min after exposure to the cleanser. METHODS: For the study, 22 Korean female subjects with normal and dry to oily skin type were recruited in this study. Study subjects were required to have face washing done within the 12 hours prior to visiting the research center, with only toner, lotion, or cream applied. The next day, the subjects visited the research center without face washing. We evaluated the skin hydration (Corneometer(®) CM 825), sebum (Sebumeter(®) SM 815), transepidermal water loss (Tewameter(®) TM 300), and pH (Skin-pH-Meter(®) PH 905) to define recovery kinetics of facial skin physiology during 180 min exposure post-cleansing. RESULTS: Skin hydration, sebum, and TEWL were significantly decreased at 20 min after washing, as compared to the baseline (P < 0.05). And skin hydration returned at 40 min, and skin sebum and TEWL returned at 120 min after washing. However, skin pH did not show significant differences at all times points. CONCLUSIONS: This study indicated that each of the skin parameters was restored at defined time points post-cleansing. Our result could be a useful reference to set the resting time in the estimation of skin bioengineering parameters.

Interval between balloon removal and oxytocin administration in cervical ripening with double-balloon in singleton pregnancies: An observational study.

OBJECTIVE: To analyze the influence of the resting interval after removal of a double-balloon for cervical ripening and oxytocin administration on the time to onset of active labor in singleton pregnancies. METHODS: A retrospective cohort study of women who required a cervical ripening with double-balloon was conducted between January 2019 and December 2022. We collected data for cervical ripening balloon insertion and removal, oxytocin administration, suspicious or pathological cardiotocographic trace, mode of delivery, maternal and neonatal complications, neonatal outcomes. Proportional hazards model comparing resting interval between double-balloon cervical ripening removal and oxytocin administration. RESULTS: A total of 403 singleton pregnancies were recruited and 213 pregnant women experienced a rest of 12 h between cervical balloon removal and oxytocin administration (resting group). Oxytocin was administered immediately after balloon removal in 190 women (non-resting group). Median insertion-to-active labor interval and insertion-to-delivery interval were significantly shorter in the non-resting group: 18.5 versus 24.0 h, HR 2.59 (CI 95%: 1.97-3.41) and 24.0 versus 29.0 h, HR 2.38 (CI 95%: 1.85-3.05) respectively. Bishop score change and mode of delivery between were similar in both groups. No differences in maternal nor neonatal complications between both groups were found. CONCLUSIONS: Oxytocin administration immediately after removal of a double-balloon for cervical ripening compared with 12 h delayed interval resulted in a shortened time from insertion to active labor onset and to delivery interval without increasing maternal or neonatal adverse outcomes.

Use of Citrated Whole Blood for Point-of-Care Viscoelastic Coagulation Testing in Dogs.

Background: A new, portable bedside coagulation monitor (VCM Vet) has provided a user-friendly, cartridge-based method to perform viscoelastic testing. However, the use of native whole blood limits the time to analyze the sample to minutes. The objective of this study is to assess whether citrated whole blood can be utilized with the cartridge-based system and whether the results are comparable to those of native whole blood. A secondary objective is to assess the viability of citrated whole blood results after up to 4 hours of resting. Methods: The study population consisted of 10 healthy mixed breed dogs. Whole blood samples were collected via jugular venipuncture. Blood was immediately transferred to the VCM test cartridge for native whole blood control group analysis per the manufacturer's instructions, and the remainder was used to fill two 3.2% sodium citrate vacutainer tubes. Test group analysis was performed on samples from each tube concurrently after a rest period of 30 min (baseline), 2 h, and 4 h. Citrated whole blood samples were recalcified for analysis immediately prior to introduction into the test cartridge. Data was recorded for all reported parameters. Results from the citrate groups were compared to the control group and to the citrated baseline to assess for differences. Overall results were compared using mixed ANOVA models. Where found, specific differences were evaluated using Tukey's test. Within-sample variation was investigated and reported as median (range). A p < 0.05 was considered significant. Results: Samples were obtained for a total of 10 control runs and 20 citrated whole blood runs. Comparison of controls to the citrated test groups revealed significant differences in CT (p < 0.001) and MCF (p < 0.002). There were no significant differences between test groups compared to citrated baselines for any parameter. Selected median coefficients of variation were 6.8% (0-68.8%) for CT, 2.4% (0-19.46%) for alpha angle, 3.2% (0-27.4%) for MCF, and 0% (0-16.3%) for 45-min LY45. Conclusion: Citrated whole blood samples can be used with the VCM Vet device; however, new reference intervals for use with citrated whole blood will be required. Results using citrated whole blood samples are not significantly different from baseline after up to 4 h of resting.

Internal cavity amplification of shell-like ferritin regulated with the change of the secondary and tertiary structure induced by PEF technology.

In this study, the effect of pulsed electric field (PEF) on apparent morphology and molecular structure of shell-like ferritin obtained from horse spleen was determined by circular dichroic (CD), fluorescence spectroscopy, Raman spectroscopy, cold field emission scanning electron microscopy (CF-SEM) and transmission electron microscopy (TEM), and verified by molecule dynamics (MD) simulation. After PEF treatment, the α-helix content of the samples reached a minimum value at 10 kV/cm, which indicated that the ferritin structure has been partially unfolded. However, the α-helix content peaked again after resting for 2 h at 25 ± 1 °C. This indicated that the PEF-treated ferritin tended to restore its original spherical morphology probably owing to the reversible assembly characteristic of ferritin. In addition, microstructure analysis revealed that ferritin particles aggregated after PEF treatment. Therefore, PEF treatment could induce the "exposure" of hydrophobic amino acids and conversion of disulfide bond configuration, and consequently, regulate the internal cavity stability of ferritin. The research will be beneficial to expand the application of PEF treatment in the modification of protein structure, and provide a theoretical basis for the application of ferritin as a carrier of bioactive molecules in food.

The impacts of rest breaks and stretching exercises on lower back pain among commercial truck drivers in Iran.

Purpose. This study aimed to determine the impacts of rest breaks and stretching exercises on lower back pain (LBP) in commercial truck drivers. Methods. This quasi-experiment was carried out on 92 truck drivers suffering from chronic LBP. Subjects were categorized into three groups (stretching exercises and rest breaks, rest breaks only and reference). Pain severity and related disability were measured at the beginning of the survey and after 6 and 12 weeks. The latter was assessed using the Oswestry low back pain disability questionnaire (OLBPDQ) and the Roland Morris questionnaire (RMQ). Results. At the end of the intervention, the mean pain scores in the three groups were 2.72 ± 1.44, 4.11 ± 0.86 and 4.90 ± 1.31 respectively (p < 0.001). The OLBPDQ scores in group 1 (stretches and resting time breaks) were significantly lower than those in group 2 (rest break) (p = 0.009). The RMQ scores showed a significant reduction in group 1 compared with the other two groups (p = 0.001). Drivers in group 2 improved more significantly than those in group 3 regarding visual analog scale pain score (p = 0.049), OLBPDQ score (p = 0.024) and RMQ score (p = 0.011). Conclusion. This study provided converging results that supplementary exercises during break periods consistently help to minimize LBP and disability.

Influence of Nano-SiO2, Nano-CaCO3 and Nano-Al2O3 on Rheological Properties of Cement-Fly Ash Paste.

Rheological curves of cement-fly ash (C-FA) paste incorporating nanomaterials including nano-SiO2 (NS), nano-CaCO3 (NC) and nano-Al2O3 (NA) at different resting times (hydration time of 5 min, 60 min, and 120 min) were tested with a rheometer. The rheological behaviors were described by the Herschel-Bulkley (H-B) model, and the influences of these nanomaterials on rheological properties of C-FA paste were compared. Results show that the types, content of nanomaterials and resting time have great influences on the rheological properties of C-FA paste. Incorporating NS and NA increases yield stress and plastic viscosity, and decreases the rheological index of C-FA paste. When the content of NS and NA were 2 wt%, the rheological index of C-FA paste was less than 1, indicating rheological behavior changes from shear thickening to shear thinning. Meanwhile, with rising resting time, yield stress and plastic viscosity increased significantly, but the rheological index decreased evidently, showing paste takes on shear thinning due to the rise of resting time. However, incorporating 3 wt% NC and the rising of resting time did not change the rheological properties of C-FA paste. These differences are mainly that the specific surface area (SSA) of NS (150 m2/g) and NA (120 m2/g) are much larger than that of NC (40 m2/g). The huge SSA of NS and NA consume lots of free water and these tiny particles accelerate the hydration process during resting time.

Effects of the resting time associated with the number of trials on the total and individual finger forces in a maximum grasping task.

The repetitive and excessive workload accompanying grip strength- or hand-intensive tasks are often considered to be common causes of work-related upper limb musculoskeletal disorders. For this reason, numerous experimental studies have been performed on maximum grip strength. However, due to an absence of standard guidelines, researchers have adopted different resting times and number of trials suited for their particular research purposes. The effects of resting time and the number of trials on the maximum total grip strength and individual finger forces of 24 participants over 20 trials were investigated. Results showed that the total grip strength and individual finger strengths differed significantly according to the resting time and the number of trials (p<0.05). Overall, grip strength tended to increase with a reduction in resting time (% reduction: 7.8%, 9.1%, 11.1%, and 13.0% for 3 min, 2 min, 1 min, and 30s resting time, respectively) as well as with an increase in the number of trials (% reduction: 8%, 10%, 13%, and 16% for 5th, 10th, 15th, and 20th trials). The effects of resting time and the number of trials also showed statistically significant effects on individual finger forces. Regression equations of total grip strength and finger forces with resting time and number of trials were established. These equations were then applied to formulate guidelines for appropriate resting times in experiments based on the number of trials and acceptable reductions in grip strength. Data from this and future studies regarding decreasing grip strength and the contribution of each finger are expected to form the groundwork for ergonomic hand tool design and development.

Meta-analysis of complication as a risk factor for early ambulation after percutaneous coronary intervention.

PURPOSE: This study systematically examined previous studies on the effect of early ambulation on vascular complications in subjects who had just undergone a percutaneous coronary intervention (PCI), and analyzed the effects of early ambulation on both hemorrhage and hematoma formation at the puncture site. METHODS: Study data were analyzed using the R (version 2.13.1) program. Publication bias was verified via regression analysis, using the logarithm of the odds ratio (OR) and sample size, and a funnel plot using sample size. The risk ratio of the incidence of bleeding and hematoma formation at the puncture site, relative to early ambulation, was confirmed using ORs and the forest plot. RESULTS: The PCI recipients' bed rest time had no significant effect on the risk ratio of hematoma formation (OR = 0.89; 95% CI = 0.68-1.17) nor the incidence of bleeding (OR = 1.14; 95% CI = 0.77-1.7) at the puncture site. CONCLUSIONS: This retrospective study's findings show that early ambulation following PCI had no effect on the incidence of either hematoma formation nor bleeding at the puncture site; however, differences in demographic factors should be considered carefully, in order to avoid interpreting the results too broadly.

Cost of territorial maintenance by Parodon nasus (Osteichthyes: Parodontidae) in a Neotropical stream

The combined demand over a certain resource may exceed its immediate supply, which can then lead to competition between individuals. This competition may result in territorial behavior. In this study we determine the density and spatial distribution, describe the interactions arising from territorial behavior and evaluate the costs of keeping the territories defended by adults of Parodon nasus. The study was conducted in Camarinha Stream located in the Serra das Araras Ecological Station, Porto Estrela, State of Mato Grosso, Brazil. The density was constant throughout the length of the stream, with a mean (± standard deviation) of 1.01 ind./m² (± 0.14). Our results show that the spatial distribution of individuals in the area ranged between uniform and random. The territories were defended more often against intraspecific than interspecific intruders. The time that the owners of the territories devoted to defending them was not influenced by the size of the territories. However, owners of larger territories spent more time foraging than owners of smaller territories. As a result, owners of larger territories had less time to rest than owners of smaller territories. The results of this study show behavioral patterns relevant to understanding the relationship between size and territorial maintenance cost of P. nasus and other species of fish with territorial behavior.(AU)

A demanda combinada por um recurso pode exceder a sua oferta imediata, levando os indivíduos a competirem. Essa competição pode resultar no comportamento de territorialidade. Neste trabalho nós determinamos a densidade e a distribuição espacial, descrevemos as interações decorrentes do comportamento territorial e avaliamos os custos de manutenção dos territórios defendidos por indivíduos adultos de Parodon nasus. O estudo foi realizado no córrego Camarinha localizado na Estação Ecológica Serra das Araras no município de Porto Estrela, Mato Grosso, Brasil. A densidade foi constante ao longo de todos os trechos, com média (± desvio padrão) de 1,01 ind./m² (± 0,14). Nossos resultados mostram que a distribuição espacial dos indivíduos na área variou entre uniforme e aleatória. Os territórios foram defendidos mais frequentemente contra invasores intra do que interespecíficos. O tempo que os detentores de território dedicaram a sua defesa não foi influenciado pelo tamanho dos territórios. Todavia, donos de territórios maiores passaram mais tempo em atividade de forrageamento que donos de territórios menores. Como consequência, donos de territórios maiores tiveram menos tempo para descansar que donos de territórios menores. Os resultados deste trabalho mostram padrões comportamentais importantes para o entendimento da relação entre tamanho e custo de manutenção dos territórios de P. nasus e de outras espécies de peixes com comportamento territorial(AU)