Are Rotations and Translations of Head Posture Related to Gait and Jump Parameters?

This study assessed the relationship between head posture displacements and biomechanical parameters during gait and jumping. One hundred male and female students (20 ± 3 yrs) were assessed via the PostureScreen Mobile® app to quantify postural displacements of head rotations and translations including: (1) the cranio-vertebral angle (CVA) (°), (2) anterior head translation (AHT) (cm), (3) lateral head translation in the coronal plane (cm), and (4) lateral head side bending (°). Biomechanical parameters during gait and jumping were measured using the G-Walk sensor. The assessed gait spatiotemporal parameters were cadence (steps/min), speed (m/s), symmetry index, % left and right stride length (% height), and right and left propulsion index. The pelvic movement parameters were (1) tilt symmetry index, (2) tilt left and right range, (3) obliquity symmetry index, (4) obliquity left and right range, (5) rotation symmetry index, and (6) rotation left and right range. The jump parameters measured were (1) flight height (cm), (2) take off force (kN), (3) impact Force (kN), (4) take off speed (m/s), (5) peak speed (m/s), (6) average speed concentric phase (m/s), (7) maximum concentric power (kW), (8) average concentric power (kW) during the counter movement jump (CMJ), and (9) CMJ with arms thrust (CMJAT). At a significance level of p ≤ 0.001, moderate-to-high correlations (0.4 < r < 0.8) were found between CVA, AHT, lateral translation head, and all the gait and jump parameters. Weak correlations (0.2 < r < 0.4) were ascertained for lateral head bending and all the gait and jump parameters except for gait symmetry index and pelvic symmetry index, where moderate correlations were identified (0.4 < r < 0.6). The findings indicate moderate-to-high correlations between specific head posture displacements, such as CVA, lateral head translation and AHT with the various gait and jump parameters. These findings highlight the importance of considering head posture in the assessment and optimization of movement patterns during gait and jumping. Our findings contribute to the existing body of knowledge and may have implications for clinical practice and sports performance training. Further research is warranted to elucidate the underlying mechanisms and establish causality in these relationships, which could potentially lead to the development of targeted interventions for improving movement patterns and preventing injuries.

Effect of Different Foot Orthosis Inverted Angles on Walking Kinematics in Females with Flexible Flatfeet.

Background: Although the inverted technique was shown to be more effective compared to other orthotic designs for the treatment of flatfeet, the biomechanical mechanisms underlying the therapeutic effect of the inverted angle orthoses is still unclear. Therefore, the aim of this study was to examine the effect of different inverted angles of foot orthoses on walking kinematics in females with flexible flatfeet. Methods: Thirty-one female adults with flexible flatfeet aged 18-35 years old participated in this study. Kinematic data of the hip, knee, and ankle were collected via BTS motion-capture system during walking under three test conditions in random order: with shoes only; with 15° inverted orthoses; and with 25° inverted orthoses. Results: Compared to the shoes only condition, both the 15° and 25° inverted orthotic conditions significantly decreased the maximum ankle plantarflexion angle during loading response, maximum ankle dorsiflexion angle during mid-stance, maximum ankle external rotation angle, and maximum ankle internal rotation angle. The maximum ankle plantarflexion angle at toe-off showed a significant decrease with the 25° inverted angle orthosis compared to both the 15° inverted angle and shoes only conditions. No significant differences were found in the knee kinematic variables, maximum hip extension angle, and maximum hip adduction angle between test conditions. Conclusion: Using inverted orthoses at 15° and 25° inverted angles resulted in significant changes in ankle joint kinematics during walking in female adults with flexible flatfeet. A 25° inverted angle orthosis significantly decreased ankle plantarflexion during push-off, potentially impacting gait mechanics. This suggests that a smaller inverted angle may be more effective for managing flexible flatfeet in female adults.

A thiazolo[5,4-d]thiazole-bridged porphyrin organic framework as a promising nonlinear optical material.

Porphyrin-based porous organic frameworks are an important group of materials gaining interest due to their structural diversity and distinct opto-electronic properties. However, these materials are seldom explored for nonlinear optical (NLO) applications. In this work, we investigate a thiazolo[5,4-d]thiazole-bridged porous, porphyrin framework (Por-TzTz-POF) with promising NLO properties. The planar TzTz moiety coupled with integrated porphyrin units enables efficient π-conjugation and charge distribution in the Por-TzTz-POF resulting in a high nonlinear absorption coefficient (ß = 1100 cm GW-1) with figure of merit (FoM) σ1/σ0 = 5571, in contrast to analogous molecules and material counterparts e.g. metal-organic frameworks (MOFs; ß = ∼0.3-0.5 cm GW-1), molecular porphyrins (ß = ∼100-400 cm GW-1), graphene (ß = 900 cm GW-1), and covalent organic frameworks (Por-COF-HH; ß = 1040 cm GW-1 and FoM = 3534).

Nonlinear Optical Switching in Regioregular Porphyrin Covalent Organic Frameworks.

Covalent organic frameworks (COFs) have garnered immense scientific interest among porous materials because of their structural tunability and diverse properties. However, the response of such materials toward laser-induced nonlinear optical (NLO) applications is hardly understood and demands prompt attention. Three novel regioregular porphyrin (Por)-based porous COFs-Por-COF-HH and its dual metalated congeners Por-COF-ZnCu and Por-COF-ZnNi-have been prepared and present excellent NLO properties. Notably, intensity-dependent NLO switching behavior was observed for these Por-COFs, which is highly desirable for optical switching and optical limiting devices. Moreover, the efficient π-conjugation and charge-transfer transition in ZnCu-Por-COF enabled a high nonlinear absorption coefficient (ß=4470 cm/GW) and figure of merit (FOM=σ1 /σo , 3565) value compared to other state-of-the-art materials, including molecular porphyrins (ß≈100-400 cm/GW), metal-organic frameworks (MOFs; ß≈0.3-0.5 cm/GW), and graphene (ß=900 cm/GW).

Mass spectrometry in freeze-drying: Motivations for using a bespoke PAT for laboratory and production environment.

Mass Spectrometry has commonly been used in the semi-conductor industry where maintaining a clean environment with minimum contaminants under high vacuum is crucial for successful manufacturing. Since the technology's early usage for pharmaceutical manufacturing in the 1980 s, particularly in the freeze-drying environment, much has changed. The focus of the current work is aimed at asking some key questions regarding the maturity of the technology, its challenges and importance of having an application-specific instrument for quantitative process analyses applied to freeze-drying. Furthermore, we compare the use of mass spectrometers in early installations from the '80s with recent experiences of the technology in the production and laboratory environments comparing data from different MS technologies. In addition, the manuscript covers broad application of the technology towards detection of and sensitivity for analytes including silicone oil and Helium. It also explores the option of using MS in detecting water vapor and nitrogen concentration not just in primary drying, but also in secondary drying. The technology, when purpose built, has the potential for use as a robust, multi-purpose PAT tool in the freeze-drying laboratory and production environments.

Ultrashort vortex from a Gaussian pulse - An achromatic-interferometric approach.

The more than a century old Sagnac interferometer is put to first of its kind use to generate an achromatic single-charge vortex equivalent to a Laguerre-Gaussian beam possessing orbital angular momentum (OAM). The interference of counter-propagating polychromatic Gaussian beams of beam waist ωλ with correlated linear phase (ϕ 0 ≥ 0.025 λ) and lateral shear (y 0 ≥ 0.05 ωλ) in orthogonal directions is shown to create a vortex phase distribution around the null interference. Using a wavelength-tunable continuous-wave laser the entire range of visible wavelengths is shown to satisfy the condition for vortex generation to achieve a highly stable white-light vortex with excellent propagation integrity. The application capablitiy of the proposed scheme is demonstrated by generating ultrashort optical vortex pulses, its nonlinear frequency conversion and transforming them to vector pulses. We believe that our scheme for generating robust achromatic vortex (implemented with only mirrors and a beam-splitter) pulses in the femtosecond regime, with no conceivable spectral-temporal range and peak-power limitations, can have significant advantages for a variety of applications.

Carbon isotope analysis of dissolved organic carbon in fresh and saline (NaCl) water via continuous flow cavity ring-down spectroscopy following wet chemical oxidation.

This work examines the performance and limitations of a wet chemical oxidation carbon analyser interfaced with a cavity ring-down spectrometer (WCO-CRDS) in a continuous flow (CF) configuration for measuring δ(13)C of dissolved organic carbon (δ(13)C-DOC) in natural water samples. Low-chloride matrix (<5 g Cl/L) DOC solutions were analysed with as little as 2.5 mg C/L in a 9 mL aliquot with a precision of 0.5 ‰. In high-chloride matrix (10-100 g Cl/L) DOC solutions, bias towards lighter δ(13)C-DOC was observed because of incomplete oxidation despite using high-concentration oxidant, extended reaction time, or post-wet chemical oxidation gas-phase combustion. However, through a combination of dilution, chloride removal, and increasing the oxidant:sample ratio, high-salinity samples with sufficient DOC (>22.5 µg C/aliquot) may be analysed. The WCO-CRDS approach requires more total carbon (µg C/aliquot) than conventional CF-isotope ratio mass spectrometer, but is nonetheless applicable to a wide range of DOC concentration and water types, including brackish water, produced water, and basinal brines.

Spontaneous rupture of a posttraumatic aneurysm of the axillary artery-a rare cause of hemorrhagic shock in children.

Posttraumatic aneurysms of the axillary artery are extremely scarce. In pediatrics, no similar case has been described. Injuries of axillary artery are often associated with ischemic complications, whereas the bleeding risks are not well documented. We report the case of a 5-year-old boy who was admitted with a scapular pulsatile lump 2 weeks after a domestic accident. During his stay, he suddenly presented a hemorrhagic shock. The patient was immediately admitted to the operating room to undergo surgical hemostasis and was then transferred to intensive care unit to stabilize his vital functions. This case shows the possibility of spontaneous and life-threatening acute bleeding of posttraumatic aneurysms of the axillary artery.

Dynamics of adipose tissue development by 2H2O labeling.

Adipose tissue development undergoes remodeling in terms of newly synthesized cells (hyperplasia) and newly synthesized lipids that accumulate in adipocytes (hypertrophy). Synthesis and/or breakdown rates of adipose cells and lipids follow a continuous and dynamic pattern, e.g., during obesity development. This chapter describes a unique in vivo method to measure the dynamics of adipose tissue growth using 2H2O labeling and mass spectrometry analyses. The approach uses 2H2O as a metabolic tracer to label the adipose tissue components such as the triglycerides (TG), the fatty acids, and the genomic DNA. Deuterium from 2H2O incorporates in the C-H bonds of glycerol moiety of TG through glyceroneogenesis as well as in palmitate moiety through de novo lipogenesis (DNL). Deuterium also incorporates into DNA through the de novo nucleoside synthesis pathway. The labeled water, 2H2O, is administrated intraperitoneally and/or orally in rodents or in humans for a defined duration and biopsies are collected at the end of the labeling period. We describe the procedure to extract, isolate, and purify the adipose components (TG-glycerol, TG-palmitate, and genomic DNA) and the derivation procedure to analyze the isotopic 2H-enrichment of these components by gas chromatography/mass spectrometry. The calculation principles are described to obtain the fractional and absolute synthesis rates of TG, of DNL, and of DNA measured in the adipose tissues. The method is nonradioactive, nonhazardous, accurate, reproducible, and very sensitive. We present recent in vivo data on the ontogeny of adipose tissue growth dynamics in young and adult obese Zucker rats compared with lean Zucker rats.

High-precision optical measurements of 13C/12C isotope ratios in organic compounds at natural abundance.

A continuous-flow cavity ring-down spectroscopy (CRDS) system integrating a chromatographic separation technique, a catalytic combustor, and an isotopic (13)C/(12)C optical analyzer is described for the isotopic analysis of a mixture of organic compounds. A demonstration of its potential is made for the geochemically important class of short-chain hydrocarbons. The system proved to be linear over a 3-fold injection volume dynamic range with an average precision of 0.95 per thousand and 0.67 per thousand for ethane and propane, respectively. The calibrated accuracy for methane, ethane, and propane is within 3 per thousand of the values determined using isotope ratio mass spectrometry (IRMS), which is the current method of choice for compound-specific isotope analysis. With anticipated improvements, the low-cost, portable, and easy-to-use CRDS-based instrumental setup is poised to evolve into a credible challenge to the high-cost and complex IRMS-based technique.

Highly efficient analysis of underivatized carbohydrates using monolithic-silica-based capillary hydrophilic interaction (HILIC) HPLC.

A polyacrylamide (PAAm)-modified monolithic silica capillary column of increased phase ratio, 200T-PAAm, for hydrophilic interaction liquid chromatography (HILIC) was prepared. The column showed high separation efficiency, with a theoretical plate height H = 7-20 microm at a linear velocity, u = 1-7 mm/s. From a kinetic plot analysis, it was expected that the monolithic column could provide three times faster separation than particle-packed HILIC columns under a pressure limit at 20 MPa. HILIC coupled with electrospray ionization (ESI)-mass spectrometry (HILIC-ESI-MS) using the 200T-PAAm column was employed for the analysis of underivatized carbohydrates to achieve fast and efficient separations of mixtures containing mono-, di-, and trisaccharides within 5 min. Under single MS full scan mode, 200 pg of oligosaccharides was detected by the system. The limit of detection (LOD) of the LC-ESI-MS/MS system was determined using selected reaction monitoring (SRM) to be as low as 3.2 ng/mL (attomol level) for nonreducing saccharides. The system was successfully applied to the detection of disaccharides in extracts of plant, such as corn, soybean, and Arabidopsis thaliana.

Highly efficient monolithic silica capillary columns modified with poly(acrylic acid) for hydrophilic interaction chromatography.

Monolithic silica capillary columns for hydrophilic interaction liquid chromatography (HILIC) were prepared by on-column polymerization of acrylic acid on monolithic silica in a fused silica capillary modified with anchor groups. The products maintained the high permeability (K=5 x 10(-14)m(2)) and provided a plate height (H) of less than 10 microm at optimum linear velocity (u) and H below 20 microm at u=6mm/s for polar solutes including nucleosides and carbohydrates. The HILIC mode monolithic silica capillary column was able to produce 10000 theoretical plates (N) with column dead time (t(0)) of 20s at a pressure drop of 20 MPa or lower. The total performance was much higher than conventional particle-packed HILIC columns currently available. The gradient separations of peptides by a capillary LC-electrospray mass spectrometry system resulted in very different retention selectivity between reversed-phase mode separations and the HILIC mode separations with a peak capacity of ca. 100 in a 10 min gradient time in either mode. The high performance observed with the monolithic silica capillary column modified with poly(acrylic acid) suggests that the HILIC mode can be an alternative to the reversed-phase mode for a wide range of compounds, especially for those of high polarity in isocratic as well as gradient elution.

Calculating optimal modulation periods to maximize the peak capacity in two-dimensional HPLC.

Theoretical calculations are presented to optimize modulation period for maximum total peak capacity in comprehensive two-dimensional HPLC (2D-HPLC) taking into account the effect of modulation on the apparent peak capacity of the first-dimension (1D) separation. Results indicate that modulation periods are most favorable when they are adjusted to approximately 2.2-4 times the standard deviation of a 1D peak in order to avoid excessively short run times at the second dimension (2D). Data are presented that effective peak capacities of several thousand in 60 min can be expected for practical 2D-HPLC conditions, utilizing 1D gradient elution followed by 2D isocratic elution, that remain at approximately 50-70% of the theoretical maximum peak capacity. This work suggests that lower modulation frequencies and longer 2D separation times than previously proposed are favorable under realistic chromatographic conditions, alleviating some practical problems associated with 2D-HPLC.

Modified Ross procedure for dysplasic ascending aorta.

We present a modification of the Ross procedure, to help reduce the risk of late pulmonary artery wall dilatation. The strength of this modified technique is its composite graft construction, consisting of a pulmonary valve autograft inserted in a Dacron tube. This composite graft can be used either as a free graft or a mini-root implant.

Enzymatic decarboxylation of tyrosine and phenylalanine to enhance volatility for high-precision isotopic analysis.

We present a rapid and selective method to increase the volatility of tyrosine and phenylalanine without adding derivative C for high-precision gas chromatography-continuous-flow isotope ratio mass spectrometry (GCC-IRMS) based on enzymatic decarboxylation to yield alkylamines and evaluated for 15N isotopic integrity. Purified tyrosine and phenylalanine were converted to tyramine and phenethylamine by tyrosine and phenylalanine decarboxylases, respectively. GC separation was achieved using a thick stationary phase (5-microm) capillary column. Recoveries were 95 +/- 2%. The reproducibility of delta15N of tyramine and phenethylamine measured by GCC-IRMS averaged SD(delta15N) = 0.33 per thousand. The absolute differences between delta15N of amino acids measured by elemental analyzer-IRMS and the alkylamines measured by GCC-IRMS was not significant. Phenethylamine and tyramine prepared from a mixture of 18 amino acids were extracted by ethanol with 95% recovery, and analysis yielded clean chromatograms and equivalent precision. These data indicate that enzymatic decarboxylation of phenylalanine and tyrosine is a convenient method to increase their volatility for continuous-flow isotopic analysis without introducing extraneous C or significant isotopic fractionation.