Efficacy of Flotation Aids Attached to the Pelvis and Thighs of Beginning Swimmers

The study aimed to experimentally verify the efficacy of wearing flotation aids to add buoyancy from the pelvis to the side of the thigh on the swimming performance of beginning swimmers who were capable of swimming around 25 meters at a time. The study recruited seven male university students who were members of the Physical Education Department and who lacked experience in specialized swimming instruction. The study found statistical difference in prone flotation between the use of flotation aids (7.27±1.92 sec) and without flotation aids (3.50±0.72 sec). During swimming for distance in a 5 min. swim test, we found statistical difference between the use of flotation aids (185.0±29.6 m) and without flotation aids (172.6±24.4 m). Moreover, no overall differences in stroke length and stroke rate were observed flotation and no flotation use

Experimental Study on Flow and Bank Erosion in Steep and Curved Trapezoidal Channels

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Effect of additional buoyancy swimsuits on performance of competitive swimmers

When in water, the Centers of Buoyancy (CoB) and Mass (CoM) of the human body are positioned cranially and caudally, respectively. With increasing distance between these centers, the sinking torque of the lower limbs increases, with a subsequent decrease in swimming performance due to increased drag. Objective: To clarify the effect of additional buoyancy swimsuits on swimming performance. Methods: The subjects were eight competitive male swimmers of mean ±SD age 21±2 years. Swimming performance was compared between Conventional (CS) and Additional Buoyancy Swimsuits (ABS). CoM and CoB were identified on land and in water, respectively, with the swimmers maintaining a horizontal posture. CoM was measured by the reaction board method. CoB was calculated as the force exerted in the vertical direction accompanied by changes in inspiratory volume. Swimming velocity and Blood Lactate (BL) concentration value during 200 m front crawl in trials at four different speeds (curve test) were recorded as swimming performance. Results: No significant difference in inspiratory volume was observed between CS and ABS (small effect size, d=0.28). The distance between CoM and CoB was significantly shorter for CS than ABS (p < 0.001; large effect size, d=1.08). Both swimming velocity at BL of 4 mmol·L-1 and maximal effort were significantly faster for ABS (p < 0.042; 0.008), with large effect size (d=0.91; 0.98). However, there was no significant difference in maximal BL between CS and ABS (small effect size, d=0.37). Conclusion: ABS improves swimming performance by streamlining the horizontal posture.This work is supported by the JSPS KAKENHI, grant number 16K01713.info:eu-repo/semantics/publishedVersio

How does 11-week detraining affect 11-12 years old swimmers’ biomechanical determinants and its relationship with 100 m freestyle performance?

The aim of this study was to analyse the detraining process that occurs during a season break, and its influence on the performance, anthropometrics, and biomechanics of young swimmers. The sample included 54 young swimmers (22 boys: 12.79 +/- 0.71 years; 32 girls: 11.78 +/- 0.85 years). Performance for the 100 m freestyle and anthropometric and biomechanical variables were evaluated as main determinants. Performance impaired significantly for boys (2.17%) and girls (1.91%). All anthropometric variables increased between moments of assessment for boys and girls. Overall, the boys enhanced all biomechanical variables during the detraining period, and girls showed mixed results. For both sexes, the stroke index was the variable with the highest increase (boys: Delta = 16.16%; d = 0.89; p = 0.001; girls: Delta = 19.51%; d = 1.06; p = 0.002). Hierarchical linear modelling showed that the height retained the amount of impairment in the performance. One unit of increase in the height (cm) led to less 0.41 s impairment in the performance. Present data indicated that during an 11-weeks detraining period, young swimmers impaired their performance, but the determinant factors showed an impaired relationship. This increase in the determinant factors is mainly related to the increase in the swimmers' anthropometrics. Moreover, the increase in height was responsible for retaining the performance impairment.This project was supported by National Funds through FCT -Portuguese Foundation for Science and Technology (UID/DTP/04045/2019), and the European Fund for regional development (FEDER) allocated by the European Union through the COMPETE 2020 Programme (POCI01-0145-FEDER-006969).info:eu-repo/semantics/publishedVersio

Comparison of swimming velocity between age-group swimmers through discrete variables and continuous variables by Statistical Parametric Mapping

The aim of this study was to compare the swimming velocity in frontcrawl between age-group swimmers using discrete variables against Statistical Parametric Mapping (SPM). The sample consisted of 30 young male swimmers divided into three groups (each with 10 swimmers) based on their age (group #1: 13.60 ± 0.84 years; group #2: 15.40 ± 0.32 years; group 3: 16.39 ± 0.69 years). Swimmers performed three maximal trials in front-crawl. The best performance was used for analysis. Comparison of swimming velocity between groups was analysed using discrete variables and as a continuous variable (SPM). As a discrete variable, the mean swimming velocity showed a significant difference between groups (p < 0.05). Moreover, when analysed by SPM, swimming velocity showed a significant difference (p = 0.021) between the ~ 44% and ~ 51% of the stroke cycle (transition of the propulsion phases between sides). Post-hoc comparison revealed a significant difference between group #1 and group #3 only in SPM analysis. Researchers, coaches, and practitioners should know that both measurement approaches can be used simultaneously. However, SPM offers more sensitive and accurate results about the swimmers’ stroke cycle.This work is supported by national funds (FCT – Portuguese Foundation for Science and Technology) under the project [UIDB/DTP/04045/2020]info:eu-repo/semantics/publishedVersio

The effect of the start and finish in the 50 m and 100 m freestyle performance in elite male swimmers

The aim of this study was to: (1) verify differences between swimmers of the same competitive level in variables related to the start and finish (50 m and 100 m freestyle); (2) verify if starting and finish variables are responsible for faster race time, and which starting variables are responsible for the start performance in such events. For the 50 m and 100 m freestyle race at the junior European Championships 2019, 86 and 88 male swimmers were analysed, respectively. A set of starting and finishing variables were used for analysis. Both races (50 m: p < 0.001; 100 m: p < 0.001) presented a significant level effect for the final race time. The same trend was observed for the start and finish performances. For both races, hierarchical linear modelling retained the 15 m mark time and finish speed as predictors. The 50 m start retained the reaction time and underwater speed, and the 100 m start retained the reaction time and the water break distance. This indicates the underwater phase of the start is of substantial importance to improve the 15 m mark time. Coaches and swimmers are advised to enhance the start underwater phase, and finish segments to improve the swimmers’ performance.This work was supported by the Fundação para a Ciência e a Tecnologia [UIDB/DTP/04045/2020].info:eu-repo/semantics/publishedVersio

Plasma Free Amino Acid Profiling of Five Types of Cancer Patients and Its Application for Early Detection

BACKGROUND: Recently, rapid advances have been made in metabolomics-based, easy-to-use early cancer detection methods using blood samples. Among metabolites, profiling of plasma free amino acids (PFAAs) is a promising approach because PFAAs link all organ systems and have important roles in metabolism. Furthermore, PFAA profiles are known to be influenced by specific diseases, including cancers. Therefore, the purpose of the present study was to determine the characteristics of the PFAA profiles in cancer patients and the possibility of using this information for early detection. METHODS AND FINDINGS: Plasma samples were collected from approximately 200 patients from multiple institutes, each diagnosed with one of the following five types of cancer: lung, gastric, colorectal, breast, or prostate cancer. Patients were compared to gender- and age- matched controls also used in this study. The PFAA levels were measured using high-performance liquid chromatography (HPLC)-electrospray ionization (ESI)-mass spectrometry (MS). Univariate analysis revealed significant differences in the PFAA profiles between the controls and the patients with any of the five types of cancer listed above, even those with asymptomatic early-stage disease. Furthermore, multivariate analysis clearly discriminated the cancer patients from the controls in terms of the area under the receiver-operator characteristics curve (AUC of ROC >0.75 for each cancer), regardless of cancer stage. Because this study was designed as case-control study, further investigations, including model construction and validation using cohorts with larger sample sizes, are necessary to determine the usefulness of PFAA profiling. CONCLUSIONS: These findings suggest that PFAA profiling has great potential for improving cancer screening and diagnosis and understanding disease pathogenesis. PFAA profiles can also be used to determine various disease diagnoses from a single blood sample, which involves a relatively simple plasma assay and imposes a lower physical burden on subjects when compared to existing screening methods

An unnatural base pair system for efficient PCR amplification and functionalization of DNA molecules

Toward the expansion of the genetic alphabet, we present an unnatural base pair system for efficient PCR amplification, enabling the site-specific incorporation of extra functional components into DNA. This system can be applied to conventional PCR protocols employing DNA templates containing unnatural bases, natural and unnatural base triphosphates, and a 3′→5′ exonuclease-proficient DNA polymerase. For highly faithful and efficient PCR amplification involving the unnatural base pairing, we identified the natural-base sequences surrounding the unnatural bases in DNA templates by an in vitro selection technique, using a DNA library containing the unnatural base. The system facilitates the site-specific incorporation of a variety of modified unnatural bases, linked with functional groups of interest, into amplified DNA. DNA fragments (0.15 amol) containing the unnatural base pair can be amplified 107-fold by 30 cycles of PCR, with <1% total mutation rate of the unnatural base pair site. Using the system, we demonstrated efficient PCR amplification and functionalization of DNA fragments for the extremely sensitive detection of zeptomol-scale target DNA molecules from mixtures with excess amounts (pmol scale) of foreign DNA species. This unnatural base pair system will be applicable to a wide range of DNA/RNA-based technologies

Highly specific unnatural base pair systems as a third base pair for PCR amplification

Toward the expansion of the genetic alphabet of DNA, we present highly efficient unnatural base pair systems as an artificial third base pair for PCR. Hydrophobic unnatural base pair systems between 7-(2-thienyl)imidazo[4,5-b]pyridine (Ds) and 2-nitro-4-propynylpyrrole (Px) were fine-tuned for efficient PCR, by assessing the amplification efficiency and fidelity using different polymerases and template sequence contexts and modified Px bases. Then, we found that some modifications of the Px base reduced the misincorporation rate of the unnatural base substrates opposite the natural bases in templates without reducing the Ds–Px pairing selectivity. Under optimized conditions using Deep Vent DNA polymerase, the misincorporation rate was extremely low (0.005%/bp/replication), which is close to that of the natural base mispairings by the polymerase. DNA fragments with different sequence contexts were amplified ∼1010-fold by 40 cycles of PCR, and the selectivity of the Ds–Px pairing was >99.9%/replication, except for 99.77%/replication for unfavorable purine-Ds-purine motifs. Furthermore, >97% of the Ds–Px pair in DNA survived in the 1028-fold amplified products after 100-cycle PCR (10 cycles repeated 10 times). This highly specific Ds–Px pair system provides a framework for new biotechnology

Comparison of performance of the 2016 ACR-EULAR classification criteria for primary Sjögren\u27s syndrome with other sets of criteria in Japanese patients

Objectives To compare the performance of the new 2016 American College of Rheumatology (ACR)-European League Against Rheumatism (EULAR) classification criteria for primary Sjögren\u27s syndrome (SS) with 1999 revised Japanese Ministry of Health criteria for diagnosis of SS (JPN), 2002 American-European Consensus Group classification criteria for SS (AECG) and 2012 ACR classification criteria for SS (ACR) in Japanese patients.Methods The study subjects were 499 patients with primary SS (pSS) or suspected pSS who were followed up in June 2012 at 10 hospitals in Japan. All patients had been assessed for all four criteria of JPN (pathology, oral, ocular, anti-SS-A/SS-B antibodies). The clinical diagnosis by the physician in charge was set as the ‘gold standard’.Results pSS was diagnosed in 302 patients and ruled out in 197 patients by the physician in charge. The sensitivity of the ACR-EULAR criteria in the diagnosis of pSS (95.4%) was higher than those of the JPN, AECG and ACR (82.1%, 89.4% and 79.1%, respectively), while the specificity of the ACR-EULAR (72.1%) was lower than those of the three sets (90.9%, 84.3% and 84.8%, respectively). The differences of sensitivities and specificities between the ACR-EULAR and other three sets of criteria were statistically significant (p<0.001). Eight out of 302 patients with pSS and 11 cases out of 197 non-pSS cases satisfied only the ACR-EULAR criteria, compared with none of the other three sets.Conclusions The ACR-EULAR criteria had significantly higher sensitivity and lower specificity in diagnosis of pSS, compared with the currently available three sets of criteria