The effect of two β-alanine dosing strategies on 30-minute rowing performance: a randomized,controlled trial

Background

β-alanine (βA) supplementation has been shown to increase intramuscular carnosine content and subsequent high-intensity performance in events lasting <?4?minutes (min), which may be dependent on total, as opposed to daily, dose. The ergogenic effect of βA has also been demonstrated for 2000-m rowing performance prompting interest in whether βA may be beneficial for sustained aerobic exercise. This study therefore investigated the effect of two βA dosing strategies on 30-min rowing and subsequent sprint performance.

Methods

Following University Ethics approval, twenty-seven healthy, male rowers (age: 24?±?2?years; body-height: 1.81?±?0.02?m; body-mass: 82.3?±?2.5?kg; body-fat: 14.2?±?1.0%) were randomised in a double-blind manner to 4?weeks of: i) βA (2.4?g·d^??1, βA1); ii) matched total βA (4.8?g on alternate days, βA2); or iii) cornflour placebo (2.4?g·d^??1, PL). Participants completed a laboratory 30-min rowing time-trial, followed by 3x30-seconds (s) maximal sprint efforts at days 0, 14 and 28 (T1-T3). Total distance (m), average power (W), relative average power (W·kg^??1), cardio-respiratory measures and perceived exertion were assessed for each 10-min split. Blood lactate ([La-]_b mmol·L^??1) was monitored pre-post time-trial and following maximal sprint efforts. A 3-way repeated measures ANOVA was employed for main analyses, with Bonferonni post-hoc assessment (P?≤?0.05).

Results

Total 30-min time-trial distance significantly increased from T1-T3 within βA1 only (7397?±?195?m to 7580?±?171?m, P?=?0.002, ?p²?=?0.196), including absolute average power (194.8?±?18.3?W to 204.2?±?15.5?W, P?=?0.04, ?p²?=?0.115) and relative average power output (2.28?±?0.15?W·kg^??1 to 2.41?±?0.12?W·kg^??1, P?=?0.031, ?p²?=?0.122). These findings were potentially explained by within-group significance for the same variables for the first 10?min split (P?≤?0.01), and for distance covered (P?=?0.01) in the second 10-min split. However, no condition x time interactions were observed. No significant effects were found for sprint variables (P?>?0.05) with comparable values at T3 for mean distance (βA1: 163.9?±?3.8?m; βA2: 161.2?±?3.5?m; PL: 162.7?±?3.6?m), average power (βA1: 352.7?±?14.5?W; βA2: 342.2?±?13.5?W; PL: 348.2?±?13.9?W) and lactate (βA1: 10.0?±?0.9?mmol·L^??1; βA2: 9.2?±?1.1?mmol·L^??1; PL: 8.7?±?0.9?mmol·L^??1).

Conclusions

Whilst daily βA may confer individual benefits, these results demonstrate limited impact of βA (irrespective of dosing strategy) on 30-min rowing or subsequent sprint performance. Further investigation of βA dosage >?2.4?g·d^??1 and/or chronic intervention periods (>?4–8?weeks) may be warranted based on within-group observations.

     

The effect of Nd:YAG laser irradiation on root surface: shear-bond strength and SEM–EDX study

To investigate the effects of Nd:YAG laser and 17% EDTA treatment on root-dentin mineral content using scanning electron microscope–energy dispersive X-ray spectroscopy (SEM–EDX) and on shear-bond strength of epoxy-resin-based sealer (AH Plus) to root dentin. Twelve extracted premolars were decoronated and roots were sectioned, so that 24 two-root halves were obtained. Element levels of each half were examined by SEM/EDX, and AH Plus build-ups were created. After shear-testing, the test surfaces were reground and subjected to a 5.25% NaOCl. Two subgroups were created according to the surface treatment (n = 12): G1, with 17% EDTA for 5 min; G2, with the Nd:YAG laser. The element level analysis and shear-bond strength test were repeated for each half; the data were recorded (MPa) and analyzed (paired samples t-test). The EDTA treatment increased the O, C, Ca/P ratio (p < 0.001), decreased Ca, P content (p = 0.000), but did not change Na, Mg content (p > 0.05). The Nd:YAG laser increased O, Ca/P ratio (p < 0.001), and decreased the Ca, P content (p = 0.000). The C, Mg, Na content did not change with the Nd:YAG laser (p > 0.05). Both 17% EDTA and Nd:YAG laser had an effect on the mineral content of roots. The 17% EDTA treatment decreased the shear-bond strength of AH Plus to root dentin (p = 0.000); however, the Nd:YAG laser did not affect the bond strength (p = 0.238). Thus, an Nd:YAG laser can be used for disinfection of the root canal when AH Plus is used as a sealer.     

The effect of metal–solvent properties on the alteration of specific zones on a carbon phase diagram

In this work Fe–Sb and Fe–Ge alloys (up to 10 wt.% Sb, Ge) were used as a solvent-catalyst for diamond synthesis at pressures of 5–6 GPa and temperatures of 1800–1900 K. Carbon solubility, capillary properties and synthesis performance of alloys were investigated. When using alloys with additive content up to 10 wt.%, rapid graphite to diamond transformation was observed. In spite of identical P,T-conditions and identical composition of a solvent–catalyst, different crystal morphology on the top and on the bottom sides of a diamond polycrystalline layer was formed, although their habit type {111} was identical. Thermodynamic and kinetic aspects of these phenomena are discussed.     

The effect of Stone–Thrower–Wales defects on mechanical properties of graphene sheets – A molecular dynamics study

The mechanical properties of graphene may be strongly affected by defects. In our work, the effects of the orientation and tilting angles of Stone–Thrower–Wales (STW, 5-7-7-5) defects on the mechanical properties of graphene have been investigated based on molecular dynamics simulations. When there is one centred STW defect including STW-1 defect and STW-2 defect, our study reveals that the orientation with respect to the chirality governs the mechanical properties of graphene. For STW-1 defective graphene, the strength of the armchair direction is much lower than that of zigzag direction. While the circumstance for STW-2 defective graphene is opposite, the strength of the armchair direction is much higher than the strength of the zigzag direction. Furthermore, when there is more than one STW defect, the mechanical properties of graphene depends on the tilting angle of STW defects. The breaking strength of graphene decreases with the increasing tilting angle. Our present work could provide significant insights into the effect of STW defects on the mechanical properties of graphene.     

The effect of a graphite addition on oxidation of ZrB2–SiC in air at 1500 °C

Dense ZrB₂ containing 15 vol.% SiC and 15 vol.% graphite was exposed to flowing air at 1500 °C. A layered scale structure developed that consisted of (1) a uniform SiO₂-rich layer on the surface, (2) a layer of ZrO₂ and SiO₂, (3) a layer of ZrO₂ (4) a partially oxidized layer composed of porous ZrB₂, ZrO₂, and graphite, and (5) unaffected ZrB₂–SiC–C. A thermodynamic model based on volatility diagrams and consistent with the experimental observations was constructed to explain the development of the layered structure. Oxidation behavior was consistent with passive oxidation and formation of a protective surface layer. Analysis indicated that it may not be possible to form a protective surface layer without actively oxidizing SiC and producing a porous partially oxidized layer between the outer protective layer and the underlying unoxidized material.     

The effect of water on the behaviour of alumina–paraffin suspensions for low-pressure injection moulding (LPIM)

The properties of ceramic powder–paraffin suspensions for low-pressure injection moulding (LPIM) is of critical importance to the successful production of high quality ceramic parts. Due to the high hygroscopicity of fine alumina powder, water introduced into the suspension at any stage of the production prior to sintering, may significantly influence its rheological behaviour and hence determine the process parameters as well as the properties of the sintered ceramics. In the industrial environment humidity cannot easily be avoided. Its effect is usually detrimental — it causes flocculation, which is usually the source of defects in sintered ceramics. However, according to the results of the present work, the effect can also be put to good use. Penetration of water into the as-moulded green parts facilitates binder removal and prevents defect formation during this processing step.     

The effect of rippled graphene sheet roughness on the adhesive characteristics of a collagen–graphene system

A great amount of effort has been made in order to reach a more precise understanding of the adhesion phenomenon that happens as a vital component of several biological systems. Therefore, a firm understanding of the important factors that influence this phenomenon is of special importance in triggering the adhesive characteristics of different biological, bio-inspired and synthetic materials in fields such as tissue engineering.In this study the adhesive characteristics of a multi-material system consisting of the frequently used synthetic material, graphene, in the form of armchair-configuration sheets, and an important biological filament which is type 1 Collagen consisting of 3 alpha helices, has been studied in detail. The main emphasis of this study is placed on understanding the effects of the roughness characteristics of the inorganic elements which are the graphene sheets on the overall adhesive features of the system which are quantified within the framework of two main criteria: adhesion energy and peeling force. At first, the methodology used in order to obtain graphene sheets with various roughness values is described in detail. The abovementioned criteria are then evaluated through Molecular Dynamics (MD) modeling of the system in the NAMD simulation software environment and various simulation scenarios are studied.     

Clinical and biochemical effects of a combination botanical product (ClearGuard™) for allergy: a pilot randomized double-blind placebo-controlled trial

Background  

Botanical products are frequently used for treatment of nasal allergy. Three of these substances, Cinnamomum zeylanicum, Malpighia glabra, and Bidens pilosa, have been shown to have a number of anti-allergic properties in-vitro. The current study was conducted to determine the effects of these combined ingredients upon the nasal response to allergen challenge in patients with seasonal allergic rhinitis.     

The effects of EPA and DHA enriched fish oil on nutritional and immunological markers of treatment naïve breast cancer patients: a randomized double-blind controlled trial

Background

We evaluated the effects of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids enriched fish oil (FO) on nutritional and immunological parameters of treatment naïve breast cancer patients.

Methods

In a randomized double blind controlled trial, the FO group (FG) patients were supplemented with 2 g/ day of FO concentrate containing 1.8 g of n-3 fatty acids during 30 days. The placebo group (PG) received 2 g/ day of mineral oil. At baseline and after the intervention, plasma levels of n-3 fatty acids, dietary intake, weight, body composition, biochemical and immunological markers were assessed.

Results

At the end of the intervention period, no between group differences were observed regarding anthropometric parameters. There was a significant increase in the plasma phospholipid EPA (p = 0.004), DHA (p = 0.007) of the FG patients. In FG patients the percentages of peripheral blood CD4⁺ T lymphocytes and serum high sensitivity C-reactive protein (hsCRP) levels were maintained while in PG patients there was a significant increase in hsCRP (p = 0.024). We also observed a significant reduction in the percentage of CD4⁺ T lymphocytes in the peripheral blood (p = 0.042) of PG patients. No changes in serum proinflammatory cytokine and prostaglandin E₂ levels were observed.

Conclusions

Supplementation of newly diagnosed breast cancer patients with EPA and DHA led to a significant change in the composition of plasma fatty acids, maintained the level of CD4⁺ T cells and serum levels of hsCRP, suggestive of a beneficial effect on the immune system and less active inflammatory response.

Trial registration

Brazilian Clinical Trials Registry (REBEC): RBR-2b2hqh. Registered 29 April 2013, retrospectively registered.

     

The milling effect of a new horizontal attrition milling in the production of (Ti0.7,W0.3)C–Ni cermet

The mechanical alloying (MA) method is a powerful and practical process to fabricate advanced materials with unique properties. Developing an effective milling process to produce high-quality powder suitable for scale-up is one of the main issues for the MA method. This study introduces a new high energy ball milling technique, the horizontal attrition ball milling (HAM). The milling effect of the HAM is superior to that of the conventional planetary and attrition milling techniques in the size reduction of particles (fragmentation) and the impact of milling (mechanical strength). The ultrafine (Ti_0.7,W_0.3)C–Ni cermet powders can be obtained by the HAM since (Ti_0.7,W_0.3)C particle growth is effectively inhibited during the carbothermal reduction. Sintered (Ti_0.7,W_0.3)C–Ni cermet by the HAM has excellent mechanical properties (hardness and fracture toughness). This study demonstrates that the newly designed HAM is a practical method for synthesizing ultrafine ceramic and composite powders appropriate to produce structural ceramics and composites that have excellent mechanical properties.     

The effect of boron containing frits on the anorthite formation temperature in kaolin–wollastonite mixtures

In order to investigate the effect of boron containing frits on anorthite formation temperature in kaolin–wollastonite mixture, four different frit compositions containing boron were prepared according to Seger formulas. One of these compositions also contained lead. Four different batches composed of 40 mass% kaolin, 40 mass% wollastonite and 20 mass% frit were prepared. The linear dilatometric (LD) curves of the batches were determined and subsequently the firing schedule (FS) curves were obtained from the LD curves. Cylindrical pellets prepared from each of the batches were fired in an especially designed furnace up to respectively 950, 975, 1000, 1025, 1050 °C. The firing period including the cooling process was adjusted to 210 min. The variation of the bulk densities of the products as a function of temperature were examined. X-ray diffraction (XRD) patterns of the products were also determined and it was observed that the minimum anorthite formation temperature was 1000 °C. Since it was known that with batches not containing any frit, the minimum anorthite formation temperature was 1100 °C, it was understood that leaded or unleaded boron containing frits decreased the anorthite formation temperatures around 100 °C.     

The impact of molecular weight on microstructure and charge transport in semicrystalline polymer semiconductors–poly(3-hexylthiophene), a model study

Electronic properties of organic semiconductors are often critically dependent upon their ability to order from the molecular level to the macro-scale, as is true for many other materials attributes of macromolecular matter such as mechanical characteristics. Therefore, understanding of the molecular assembly process and the resulting solid-state short- and long-range order is critical to further advance the field of organic electronics. Here, we will discuss the structure development as a function of molecular weight in thin films of a model conjugated polymer, poly(3-hexylthiophene) (P3HT), when processed from solution and the melt. While focus is on the microstructural manipulation and characterization, we also treat the influence of molecular arrangement and order on electronic processes such as charge transport and show, based on classical polymer science arguments, how accounting for the structural complexity of polymers can provide a basis for establishing relevant processing/structure/property-interrelationships to explain some of their electronic features. Such relationships can assist with the design of new materials and definition of processing protocols that account for the molecular length, chain rigidity and propensity to order of a given system.     

The deactivation study of Co–Ru–Zr catalyst depending on supports in the dry reforming of carbon dioxide

Carbon dioxide reforming of methane was performed over Co–Ru–Zr catalyst (0.4 wt% Ru added, calcined at 400 °C) with different supports (SiO₂, γ-Al₂O₃ and MgO) in order to study their deactivation. The Co–Ru–Zr/γ-Al₂O₃ showed the highest activity at first, but severe deactivation was observed due to carbon deposition. Co–Ru–Zr/MgO exhibited low activity because of its low specific surface area. However, the high conversions could be obtained in Co–Ru–Zr/SiO₂, and activity was kept almost constantly for 500 h reaction. The characteristics of the catalysts, before and after the reaction, were investigated employing BET, XRD, TPR, TGA-DTA and TEM.     

The effect of Al–O substitution for Si–N on the luminescence properties of YAG:Ce phosphor

The present paper describes the effect of various Si–N substitution degree on the crystal structure and optical properties of yellow YAG:Ce phosphor commonly used with combination of InGaN in white LEDs. It has been found that the course of silicon/nitrogen YAG:Ce garnet doping as well as formation of the liquid phase and its chemical composition controlled formation of the side phase besides YAG:Ce. Substitution of Al–O for Si–N chemical bonds according to the general formula Y_2.94Ce_0.06Al_(5?x)Si_xO_(12?x)N_x was confirmed by changes of the unit cell parameter and formation of the Si–N bonds as detected by FT-IR studies. Formation of the nitrogen ligand in cerium arrangement resulted in a red shift in emission spectrum of trivalent cerium if nominal x value was in the range of 0.2–0.3. Above x = 0.3 only decrease of emission intensity was observed because of the secondary phase precipitation but further solution of Si–N in YAG:Ce crystal lattice cannot be excluded.     

A randomized controlled trial of the effect of fish oil supplementation in late pregnancy and early lactation on the n−3 fatty acid content in human breast milk

The aim of this research was to investigate the effect of fish oil supplementation, in the third trimester of pregnancy and early lactation period of healthy pregnant Danish women. Forty-four pregnant women were randomly allocated to fish oil supplementation (1.3 g EPA and 0.9 g DHA per day) from week 30 of gestation (FO-group) or to a control regimen (olive oil or no oil; controls). The FO-group was randomly subdivided into women stopping fish oil supplementation at delivery [FO(pregn)], and women continuing supplementation for an, additional 30 d [FO(pregn/lact)]. Thirty-six women agreed to collect milk samples at days 4, 16, and 30 postpartum. The FA composition of the milk samples was determined by GLC. At days 4, 16, and 30 in lactation, FO(pregn/lact) women (n=12) had, respectively 2.3 (P=0.001), 4.1 (P=0.001), and 3.3 (P=0.001) times higher mean contents of LCPUFA(n−3) in their breast milk compared with controls (n=13), and 1.7 (P=0.005), 2.8 (P=0.001), and 2.8 (P=0.001), times higher LCPUFA(n−3) contents, respectively, at these days compared with FO(pregn) women (n=11). The latter group did not differ significantly from controls with regard to LCPUFA(n−3) content in the breast milk. Similar results were obtained when analyzing separately for effects on the milk content of DHA. Dietary supplementation with 2.7 g LCPUFA(n−3) per day from week 30 of gestation and onward more than tripled the LCPUFA(n−3) content in early breast milk; supplementation limited to pregnancy only was much less effective.     

The effect of scale and interfacial tension on liquid–liquid dispersion in in-line Silverson rotor–stator mixers

The effect of scale, processing conditions, interfacial tension and viscosity of the dispersed phase on power draw and drop size distributions in three in-line Silverson rotor–stator mixers was investigated with the aim to determine the most appropriate scaling up parameter. The largest mixer was a factory scale device, whilst the smallest was a laboratory scale mixer. All the mixers were geometrically similar and were fitted with double rotors and standard double emulsor stators. 1 wt.% silicone oils with viscosities of 9.4 mPa s and 339 mPa s in aqueous solutions of surfactant or ethanol were emulsified in single and multiple pass modes. The effect of rotor speed, flow rate, dispersed phase viscosity, interfacial tension and scale on drop size distributions was investigated.     

The influence of the mixed alkaline earth effect on the structure and properties of (Ca,Mg)–Si–Al–O–N glasses

Alkaline earth oxynitride glasses of (Ca, Mg)–Si–Al–O–N with different CaO/(CaO + MgO) molar ratios (0, 0.25, 0.5, 0.75, and 1) were successfully prepared using the sol-gel method, and their structural compositions were characterised by Raman and FT-IR techniques. The glass dynamic properties of thermal expansion coefficient, glass transition temperature (T_g), and static properties of density, molar volume, Vickers hardness and compressive strength were systematically measured and analysed. The results showed that the static properties exhibited an overall regular change as the CaO/(CaO + MgO) ratio gradually increased, while the dynamic properties had an obvious mixed alkaline earth effect, which represented the appearance of an extreme value point in CaO/(CaO + MgO) mole ratios of 0.25 and 0.75, respectively. The typical thermal expansion coefficient and T_g of mixed alkaline earth oxynitride glasses deviated far from the linear connection between single alkaline earth oxynitride glasses. Raman spectra and infrared spectra revealed that the ratio value of the Q³/(Q²+Q⁴) decreased (Qⁿ: n = no. of bridging anions joining SiO₄ tetrahedra) in the mixed alkaline earth oxynitride glasses with increasing the amount of Ca, confirming that Ca decreased the crosslinking between individual tetrahedra via the transformation of Q³ species into Q² and Q⁴ species.     

The effect of compositional changes on the crystallization behaviour and mechanical properties of diopside–wollastonite glass-ceramics in the SiO2–CaO–MgO (Na2O) system

The crystallization process of ternary system SiO₂–CaO–MgO (Na₂O) was investigated by DTA, XRD and SEM techniques and by strength measurements. The ability of Cr₂O₃+Fe₂O₃ as nucleating agents in inducing bulk nucleation via formation of a spinel phase was proved. Wollastonite and diopside are two major phases that were identified after two-stage heat treatment. The spherulitic growth morphology was observed by SEM. At high growth temperatures for long times the recrystallization process was observed too. The kinetic parameters, such as activation energy and Avrami exponent, were calculated by Kissinger equation.     

An ultrasonic study on ternary xPbO–(45-x)CuO–55B2O3 glasses

A series of xPbO–(45-x)CuO–55B₂O₃ glasses (5 ≤ x ≥ 40 mol %) were prepared by the melt-quenching technique. The X-ray diffraction (XRD) patterns of the prepared glasses are found to have amorphous structure. An extensive ultrasonic study has been made to explore the structural role of PbO and CuO in the borate network. Various elastic properties were calculated from the measured data of density and ultrasonic velocity. Ultrasonic velocity and elastic moduli revealed broad humps at about 20 mol % PbO, which are attributed to the borate anomaly. Below 20 mol % PbO, all Pb²⁺ ions are considered to be entering the borate network as a glass modifier. This results in the transforms the borate network from an open structure to a denser three-dimensional structure due to BO₃ → BO₄ conversion. Beyond 20 mol, addition of PbO results in the formation of metaborate, pyroborate, and orthoborate units with NBOs. This weakness the glass structure and decrease both ultrasonic velocity and elastic moduli. The elastic properties were predicted and quantitatively analyzed by taking into account the effect of boron coordination number on the compositional and structural parameters involved in Makishima–Mackenzie's theory, ring deformation model and bond compression model. An excellent agreement between the computed theoretical and experimental elastic moduli, micro-harness and Poisson's ratio was achieved for majority of samples.