Increase In VE Research Articles

The pontine Kölliker-Fuse nucleus is important for reduced post-inspiratory airflow elicited by stimulation of the ventral respiratory parafacial region.

Considering that the retrotrapezoid nucleus/respiratory parafacial region (RTN/pFRG) would be an important center in the central nervous system involved in the maintenance and modulation of respiratory activity, we hypothesized that neurons in this nucleus would also be involved in the postinspiratory phase of the respiratory cycle through a connection with the pontine Kölliker-Fuse (KF) region. Here we performed pharmacogenetic manipulation (AAV-hM3D(Gq)-mCherry or AAV-hM4D(Gi)-mCherry) in VGlut2-cre, Ai6 conscious mice to evaluate breathing parameters through whole body plethysmography under baseline conditions (normoxia: FiO2 = 0.21) or under hypercapnia or hypoxia challenges (FiCO2 = 0.07 or FiO2 = 0.08). Under normoxia, selective stimulation of RTN/pFRG resulted in a smaller increase in VE (1,272 ± 102.5, vs. RTN/pFRG stimulation: 1,878 ± 122.1 ml/kg/min), due to a smaller increase in VT (5.4 ± 0.35, vs. RTN/pFRG stimulation: 7.77 ± 0.21 ml/kg) without changing fR in a condition of KF inhibition. However, inhibition of the VGlut2 neurons in the KF did affect the TE1 produced by selective activation of RTN/pFRG (119.9 ± 2.53, vs. RTN/pFRG stimulation: 104 ± 2.46 ms). Both the hypercapnia and hypoxia ventilatory response were reduced after inhibition of VGlut2-expressing KF neurons. Therefore, consistent with anatomical projections RTN/pFRG neurons regulate lung ventilation by controlling all aspects of breathing, i.e breathing frequency, inspiration, postinspiration and active expiration. All the modulation seems to be dependent on the integrity of the glutamatergic neurons in the KF region.

Effectiveness of a dose-graded aerobic exercise regimen on cardiopulmonary fitness and physical performance in pediatric survivors of acute lymphoblastic leukemia: a randomized clinical trial.

To determine whether a 12-week supervised dose-graded aerobic exercise (D-GAE) training, when implemented in conjunction with traditional rehabilitation, could help pediatric survivors of acute lymphoblastic leukemia (ALL) enhance their cardiopulmonary capacity and improve their physical performance. Fifty-eight pediatric survivors of ALL (age 13.78 ± 2.47years; boys 60.34%) were assigned at random to either undergo the D-GAE in addition to the traditional physical rehabilitation (D-GAE group; n = 29) or the traditional physical rehabilitation solely (control group; n = 29). The cardiopulmonary fitness (peak oxygen uptake (VO2peak), ventilatory equivalent (VEq/VO2), minute ventilation (VE, L/min), oxygen pulse (O2P), maximum heart rate (HRmax), 1-min heart rate recovery (HRR1), and respiratory exchange ratio (RER)) and physical performance (6-min walk test (6-MWT), timed up and down stairs (TUDS), and 4 × 10-m shuttle run test (4 × 10mSRT)) were assessed on the pre- and post-intervention occasions. The mixed-model ANOVA revealed a meaningful increase of VO2peak (P = .002), VE (P = .026), O2P (P = .0009), HRmax (P = .004), and HRR1 (P = .011), and reduction of VEq/VO2 (P = .003) and RER (P = .003) in the D-GAE group compared with the control group. Besides, the analysis detected a favorable increase in the physical performance for the D-GAE group (6-MWT (P = .007), TUDS (P < .001), 4 × 10mSRT (P = .009)). A 12-week D-GAE program in conjunction with traditional rehabilitation holds promise in enhancing cardiopulmonary fitness and improving the physical performance of pediatric survivors of ALL. Clinicians and physical rehabilitation professionals can, therefore, integrate the D-GAE into the traditional rehabilitation protocols for such a patient population to optimize their cardiopulmonary fitness and physical function, while also facilitating a gradual transition to practice and adaption. The favorable outcomes of this study bolster the inclusion of D-GAE as a crucial element in the care and rehabilitation of pediatric survivors of ALL. By embracing these findings, healthcare professionals and oncologists can contribute to mitigating the long-term cardiopulmonary and physical complications associated with cancer treatments and fostering a state of enhanced well-being and increased physical activity among survivors.

Postnatal Development of the Purinergic Signaling System in the preBötzinger Complex; Implications for the Hypoxic Ventilatory Response

The hypoxic ventilatory response (HVR) comprises a carotid body‐mediated increase in ventilation followed by a secondary, CNS‐mediated decrease, the hypoxic respiratory depression (HRD), that is larger and potentially life‐threatening in newborn mammals. The mechanisms responsible for the greater HRD in newborns are unknown, but purinergic signaling via P2 and P1 receptor (R) mechanisms helps shape this 2° phase. Shortly after the 1° increase in ventilation, astrocytes release ATP in the preBötzinger Complex (preBötC, site of inspiratory rhythm generation), which stimulates breathing via P2Y1Rs and attenuates the HRD. Extracellular ATP (ATPe) is degraded to adenosine (ADOe), which inhibits breathing and is implicated in the HRD. Thus, the impact of ATP on the HVR is determined by the balance between the actions of ATP and ADOe, that could change developmentally and contribute to the greater HRD of newborns. Our goal was to characterize how the many factors that determine the balance between ATP and ADOe signaling change during development, including: P2Y1Rs; ADO A1Rs; ectonucleotidases (ECTOs) that degrade ATPe to ADOe; ADOe clearance by equilibrative nucleoside transporters (ENTs) via transmembrane transport of ADO down its concentration gradient; and ADO kinase (ADK), which is not mature in the cortex until postnatal day (P) 14, but facilitates ADOe clearance by converting ADOi into AMP so that ADOi&lt;ADOe. We used rhythmic preBötC slice preparations to characterize developmental changes in: i) the effects of P2Y1R and ADOR signaling on preBötC rhythm; ii) ECTO activity; and iii) the impact of ENTs and ADK on baseline preBötC rhythm and preBötC responses to ATP and ADO that were locally injected to simulate hypoxia. iv) In vivo head‐out plethysmography was used to assess the role of ADOe clearance mechanisms in shaping the developing HVR.i) The frequency (freq) increase evoked by ATP in the preBötC doubled between P0‐6 and P9‐12, but the P2Y1R agonist MRS 2365‐evoked increase did not change. The A1R inhibition of freq was of similar magnitude but greater duration at P0‐6 compared to P9‐12. ii) ECTO activity, assessed by incubating preBötC tissue in ATP and measuring PO4, was greater at P9‐12. iii) The ADO freq inhibition was 2‐fold longer in ENT knockout mice compared to WT mice at all ages. ADK inhibition (ABT 702) inhibited baseline freq only at P9‐12. iv) Knockout of ENTs blunted the freq response to hypoxia (10% O2) in vivo, but increased the VT response at all ages. Introduction of constitutively active ADK into the brain produced P0‐2 ADKtg mice that responded to hypoxia with an adult‐like, sustained increase in VE/VO2; P0‐2 WT C57BL6 did not respond to hypoxia. This difference disappeared by P6‐8. Surprisingly, the mature HVR of P0‐2 ADKtg mice reflected a greater hypoxic depression of VO2, not a greater increase in VE.Data suggest preBötC sensitivity to P2Y1 and A1Rs does not change, while ECTO activity increases developmentally. ADO actions are prolonged in P0‐6 mice, suggesting that ADOe clearance mechanisms mature postnatally. ENTs appear to play a similar role from birth, which may involve clearing ADOe from the preBötC during hypoxia. ADK maturation also appears important in the development of an adaptive HVR. However, the role of ADK in modulating VE vs metabolic responses to hypoxia remains to be elucidated.

Impact of ageing and pregnancy on the minute ventilation/carbon dioxide production response to exercise.

Ventilatory efficiency can be evaluated using the relationship between minute ventilation (V'E) and the rate of CO2 production (V'CO2 ). In accordance with the modified alveolar ventilation equation, this relationship is determined by changes in dead space volume (V D) and/or the arterial CO2 tension (P aCO2 ) equilibrium point. In this review, we summarise the physiological factors that may account for normative ageing and pregnancy induced increases in V'E/V'CO2 during exercise. Evidence suggests that age-related increases in V D and pregnancy-related decreases in the P aCO2 equilibrium point are mechanistically linked to the increased V'E/V'CO2 during exercise. Importantly, the resultant increase in V'E/V'CO2 (ratio or slope), with normal ageing or pregnancy, remains below the critical threshold for prognostic indication in cardiopulmonary disease, is not associated with increased risk of adverse health outcomes, and does not affect the respiratory system's ability to fulfil its primary role of eliminating CO2 and maintaining arterial oxygen saturation during exercise.

The effect of counter-ion substitution on poly(phthalazinone ether ketone) amphoteric ion exchange membranes for vanadium redox flow battery

The study proposed a novel method to prepare poly(phthalazinone ether ketone) amphoteric ion exchange membranes (Q/S-M) with both increased efficiency and chemical stability for vanadium redox flow battery (VRB) applications. Q/S-M membranes were obtained after the successive amination and acidification process of blend base membranes prepared from brominated poly(phthalazinone ether ketone) (BPPEK) and sulfonated poly(phthalazinone ether ketone) substituted by counter-ions (SPPEK-M), where M was defined as counter-ions: Li+, Na+ and K+. The study analyzed the effect of counter-ion size on properties of Q/S-M membranes, which were compared with those for Q/S membrane obtained from BPPEK and SPPEK in acid form. Q/S and Q/S-M membranes maintained the same composition of ionic groups. The Q/S-M membranes induced by bigger counter-ion size showed the increasing of water content and ion diffusion rate, which was higher than that of Q/S membrane. Related to Q/S membrane, Q/S–K membrane possessed almost half area resistance (0.67 Ω cm2 vs 1.43 Ω cm2), and the value was close to that of Nafion115. Q/S-M membranes exhibited a 96.0–98.8% decrease in VO2+ permeability over Nafion115. Q/S–K membrane displayed a 6.5% increase in VE and correspondingly a 6.2% increase in EE over Q/S membrane, maintaining superior EE than Nafion115 (89.7% vs 86.5%). The ex-situ degradation test in VO2+ solutions indicated that despite close EE, Q/S–K membrane showed superior chemical stability over amphoteric ion exchange membranes (AIEMs) in our previous works. There was no obvious efficiency decay of Q/S–K membrane during 100-cycles test, indicating the good duration in operating VRB.

Plaučių navikų ilgosios ašies ir tūrių pokyčio palyginimas vertinant atsaką į gydymą

Plečiantis plaučių vėžio (PV) gydymo metodams ir galimybėms, kasdienėje klinikinėje praktikoje vis dažniau susiduriama su taikomų naviko atsako į gydymą vertinimo metodikų ribotumo ir tobulinimo klausimais. Standartizuota solidinių navikų atsako vertinimo metodika RECIST (angl. Response Evaluation Criteria in Solid Tumours) 1.1 ne visais atvejais gali užtikrinti ankstyvą progresuojančios ligos nustatymą. Tyrimo tikslas. Išanalizuoti išmatuojamų navikų matmenų ir tūrių pokyčių skirtumus, vertinant PV atsaką į gydymą kompiuterinės tomografijos (KT) vaizduose. Tyrimo metodai. Retrospektyviai įvertinti 2016–2019 m. įprastai atliktų KT tyrimų duomenys. Atrankos kriterijai: verifikuotas nesmulkių ląstelių PV, KT tyrimas atliktas prieš gydymą ir du KT tyrimai gydant; plaučiuose nustatytas bent vienas išmatuojamas navikinis darinys. Matuotas navikinio darinio ilgosios ašies matmuo (IA) ir tūris pagal elipsės (VT) ir sferos modelius (VS). Matavimai atlikti rankiniu ir pusiau automatiniu būdu, naudojant VitreaWorkstation™ CAD programinę įrangą. Dydžių pokyčiai vertinti remiantis RECIST 1.1 kategorijomis: progresuojanti liga (PL), dalinis atsakas ir stabili liga. Rezultatai. Tyrime analizuoti 125 pacientų duomenys. Išmatuoti 145 navikiniai dariniai ir įvertintas jų atsakas į gydymą. Nustatytas labai stiprus ryšys tarp IA ir VT prieš gydymą ir gydant (atitinkamai r=0,921, I r=0,937, II r=0,920). Vertinant VT pokyčius I ir II kontrolinių tyrimų vaizduose, PL nustatyta dažniau nei vertinant IA pokyčius, atitinkamai – 13,8 proc. ir 6,9 proc. Remiantis VT padidėjimu, I kontroliniame tyrime nustatytas PL dažnis 36,6 proc. (n=53) atitiko IA II kontroliniame tyrime nustatytą PL dažnį 35,9 proc. (n=52). Išvada. Nustatytas labai stiprus ryšys tarp naviko IA ir VT. Naviko VT padidėjimas gali būti jautresnis būdas įvertinti PL PV sergantiems pacientams.

Early Prediction of Treatment Response of Neuroendocrine Hepatic Metastases after Peptide Receptor Radionuclide Therapy with 90Y-DOTATOC Using Diffusion Weighted and Dynamic Contrast-Enhanced MRI.

The purpose of this study was to determine if parameters derived from diffusion-weighted (DW-) and dynamic contrast-enhanced (DCE-) magnetic resonance imaging (MRI) can help to assess early response to peptide receptor radionuclide therapy (PRRT) with 90Y-DOTATOC in neuroendocrine hepatic metastases (NET-HM). Twenty patients (10 male; 10 female; mean age: 59.2 years) with NET-HM were prospectively enrolled in this single-center imaging study. DW-MRI and DCE-MRI studies were performed just before and 48 hours after therapy with 90Y-DOTATOC. Abdominal SPECT/CT was performed 24 hours after therapy. This MRI imaging and therapy session was repeated after a mean interval of 10 weeks. Up to four lesions per patient were evaluated. Response to therapy was evaluated using metastasis sizes at the first and second therapy session as standard for comparison (regressive, stable, and progressive). DW-MRI analysis included the apparent diffusion coefficient (ADC) and parameters related to intravoxel incoherent motion (IVIM), namely, diffusion (D), perfusion fraction (f) and pseudo-diffusion (D∗). DCE-MRI analysis comprised Ktrans, ve and kep. For statistical analysis of group differences, one-way analysis of variance (ANOVA) and appropriate post hoc testing was performed. A total of 51 lesions were evaluated. Seven of 51 lesions (14%) showed size progression, 18/51 (35%) regression, and 26/51 (51%) remained stable. The lesion-to-spleen uptake ratio in SPECT showed a decrease between the two treatment sessions that was significantly stronger in regressive lesions compared with stable (p = 0.013) and progressive lesions (p = 0.021). ANOVA showed significant differences in mean ADC after 48 h (p = 0.026), with higher ADC values for regressive lesions. Regarding IVIM, highest values for D at baseline were seen in regressive lesions (p = 0.023). In DCE-MRI, a statistically significant increase in ve after 10 weeks (p = 0.046) was found in regressive lesions. No differences were observed for the transfer constants Ktrans and kep. Diffusion restriction quantified as ADC was able to differentiate regressive from progressive NET-HMs as early as 48 hours after PRRT. DW-MRI therefore may complement scintigraphy/SPECT for early assessment of response to PRRT. Assessment of perfusion parameters using IVIM and DCE-MRI did not show an additional benefit.

Use of the "Cool Fat Burner" in conjunction with drinking of cold water is associated with acute and minor increases in energy expenditure and fat metabolism in overweight men and women.

Exposure to cold is associated with increased energy expenditure to maintain thermal equilibrium. The Cool Fat Burner vest and Gut Buster are chilling devices used to induce shivering and increase calorie use. Drinking chilled water has a similar effect. Indirect calorimetry was performed on volunteers at rest with induced shivering. Eight men and 6 women with a mean age of 32.14+7.26 years were evaluated while wearing the Cool Fat Burner Vest and Gut Buster and drinking chilled water. Use of the chilling devices was associated with a significant increase in VO2, VT, VE, R, and EE. An over 20% increase in fat use as a fuel source was observed along with a 67% increase in EE. The energy expenditure during the final 30 minutes of shiver chilling was 74.6% above that of the RMR. Chilling induced significant increases in energy expenditure associated with a shift in energy source towards more fat tissue use. Indirect calorimetry evaluation of overweight subjects wearing a Cool Fat Burner vest and Gut Buster and drinking chilled water demonstrated significant increases in oxygen uptake and energy expenditure, and a shift in fuel utilization towards fat as the substrate of choice.

Dynamic contrast-enhanced (DCE) MRI derived kinetic perfusion indices may help predicting seizure control in single calcified neurocysticercosis

BackgroundThe factors responsible for seizure recurrence in patients with Solitary calcified neurocysticercosis (NCC) are not well understood. Blood brain barrier (BBB) breach may be associated with seizure recurrence. Dynamic contrast enhanced (DCE) MRI derived indices kep, ktrans and ve are useful in quantifying BBB permeability. In this study, we assessed the possible role of DCE-MRI and matrix metalloproteinases (MMP)-9 levels in predicting seizure recurrence. MethodsIn this prospective-observational study, patients with new-onset seizures and a solitary calcified NCC were included. DCE-MRI was done to quantify BBB integrity. DCE-MRI parameters were measured as kep, ktrans and ve. MMP-9 levels were estimated. Patients were followed for 1 year, when DCE-MRI and MMP-9 levels were repeated. Patients were classified into two groups on the basis of seizure recurrence, which was defined as the recurrence of an episode of seizure at least 1 week after the initiation of the anti-epileptic drugs. Logistic regression analysis was done. ResultsAt 1-year of follow up, 8 out of 32 patients had seizure recurrence. Baseline DCE-MRI derived kep (p = 0.015) and MMP-9 levels (p = 0.019) were significantly higher in the seizure “recurrence” group compared with the “no recurrence” group. On within-group analysis, a significant increase in kep (p = 0.012), ve (p = 0.012), and MMP-9 levels (p = 0.017) was observed in the seizure “recurrence” group while a decrease was seen in ve and MMP-9 levels in the “no recurrence” group. ConclusionHigher values of DCE-MRI indices and MMP-9 levels, with a corresponding trend in the follow-up, can be useful in predicting lesions with a higher propensity for seizure recurrence.

Fourier analysis of He 4471/Mg 4481 line profiles for separating rotational velocity and axial inclination in rapidly rotating B-type stars

While the effect of rotation on spectral lines is complicated in rapidly-rotating stars because of the appreciable gravity-darkening effect differing from line to line, it is possible to make use of this line-dependent complexity to separately determine the equatorial rotation velocity (ve) and the inclination angle (i) of rotational axis. Although line-widths of spectral lines were traditionally used for this aim, we tried in this study to apply the Fourier method, which utilizes the unambiguously determinable first-zero frequency (sigma1) in the Fourier transform of line profile. Equipped with this technique, we analyzed the profiles of HeI 4471 and MgII 4481 lines of six rapidly-rotating (vesini~150-300km/s) late B-type stars, while comparing them with the theoretical profiles simulated on a grid of models computed for various combination of (ve, i). According to our calculation, sigma1 tends to be larger than the classical value for given vesini. This excess progressively grows with an increase in ve, and is larger for the He line than the Mg line, which leads to sigma1He > sigma1Mg. It was shown that ve and i are separately determinable from the intersection of two loci (sets of solutions reproducing the observed sigma1 for each line) on the ve vs. i plane. Yet, line profiles alone are not sufficient for their unique discrimination, for which photometric information (such as colors) needs to be simultaneously employed.

Measuring the Energy of Ventilation and Circulation during Human Walking using Induced Hypoxia

Energy expenditure (EE) during walking includes energy costs to move and support the body and for respiration and circulation. We measured EE during walking under three different oxygen concentrations. Eleven healthy, young, male lowlanders walked on a treadmill at seven gait speeds (0.67–1.83 m s−1) on a level gradient under normobaric normoxia (room air, 21% O2), moderate hypoxia (15% O2), and severe hypoxia (11% O2). By comparing the hypoxia-induced elevation in heart rate (HR [bpm]), ventilation (VE [L min−1]) with the change in energy expenditure (EE [W]) at each speed, we were able to determine circulatory and respiratory costs. In a multivariate model combining HR and VE, respiratory costs were 0.44 ± 0.15 W per each L min−1 increase in VE, and circulatory costs were 0.24 ± 0.05 W per each bpm increase in HR (model adjusted r2 = 0.97, p < 0.001). These VE costs were substantially lower than previous studies that ignored the contribution of HR to cardiopulmonary work. Estimated HR costs were consistent with, although somewhat higher than, measures derived from catheterization studies. Cardiopulmonary costs accounted for 23% of resting EE, but less than 5% of net walking costs (i.e., with resting EE subtracted).

Abstract P6-01-03: Trastuzumab-induced hypoxia changes in a HER2+ murine model of breast cancer

Abstract Introduction: The primary goal of this study is to quantitatively map the changes in perfusion and hypoxia in response to trastuzumab treatment through imaging and immunohistochemical studies in a murine model of HER2+ breast cancer. Correlating quantitative imaging data with pathological validation of vessel architecture will identify the temporal changes in vascular function, which will enable optimizing the order and timing of multi-modal (i.e., trastuzumab, chemo- and radiation) therapy, leading to significantly improved anticancer response. Experimental Design: Mice were implanted subcutaneously with BT474 breast cancer cells (1×107) and randomly assorted into groups: treated (10 mg/kg trastuzumab) or control (saline). After tumors reached ∼225 mm3, animals (n = 20) were imaged with dynamic contrast enhanced-MRI (7.0 T MRI) before treatment (day 0), and 24 hours after each treatment (day 1 and day 4). Pharmacokinetic parameters, Ktrans and ve, were extracted. Subgroups of animals were sacrificed for histology between days 0 through 7 (n = 36). Tumor sections were paraffin-embedded and stained with CA-IX, CD31, α-SMA, Ki67 and H&amp;E. Slides were scanned in high resolution (20×) and quantitatively analyzed with Leica SCN400 software. Another cohort of animals (n = 32) was utilized to identify longitudinal changes in functional vascular (Hoechst 33342) and hypoxia (pimonidazole) through immunofluorescence. Agents were injected prior to sacrifice between days 0 through 7 and tumors were immediately frozen for processing. Results: Treated tumors exhibited a significant increase in Ktrans (p = 0.03) on day 4 compared to controls, indicative of heightened vessel perfusion and/or permeability. Additionally on day 4, treated tumors exhibited a significant increase in ve (p = 0.01), the extravascular extracellular volume fraction, indicating increased cell death. Significant decreases in Ki67 proliferation staining (p = 0.02) and tumor volume at day 7 (p = 0.04) in the treated group confirmed tumor response to trastuzumab. Immunohistochemical analyses revealed treated tumors have a significant decrease in CD31 microvessel density staining (p = 0.01), with a simultaneous significant increase in α-SMA pericyte coverage staining (p = 0.05) on day 4; thus, there was an overall increase in the "vessel maturation index" (ratio of α-SMA to CD31 staining) compared to controls (p = 0.01). CA-IX staining demonstrated increased hypoxia in the control group compared to treated, showing significant increases on day 3 (p = 0.03) and day 7 (p = 0.002). Qualitative differences were noted between control and treated groups for both functional vasculature and pimonidazole hypoxia fluorescent staining. Conclusion: Increased intratumoral vascular delivery (Ktrans) with a simultaneous increase in vessel maturation (immunohistochemistry) are exhibited on day 4 post trastuzumab treatment. Additionally, decreased hypoxia is revealed in treated tumors compared to controls. Hypoxic tumor cells show resistance to both radiation and chemotherapy, therefore temporarily improving the tumor's functional vasculature and decreasing hypoxia during trastuzumab treatment has potential to enhance the effectiveness of these combination therapies. Citation Format: Sorace AG, Quarles CC, Yankeelov TE. Trastuzumab-induced hypoxia changes in a HER2+ murine model of breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-01-03.

Double product break point estimates ventilatory threshold in individuals with type 2 diabetes.

[Purpose] To verify the identification of the anaerobic threshold through the double product breakpoint (DPBP) method for individuals with type 2 diabetes. [Subjects and Methods] Nine individuals with T2D (7 females; age=63.2 ± 8.9 y) and 10 non-diabetic (ND) (7 females; age=58.3 ± 7.8 y) performed an incremental exercise test on a cycle ergometer. Heart rate (HR), blood pressure (BP) and expired gas were measured at the end of each stage. The ventilatory threshold (VT) and DPBP were considered as the exercise intensities above which an over proportional increases in VE and DP were observed in relation to increasing workload. [Results] No differences were observed between the workloads, HR and VO2 corresponding to the AT identified respectively by VT and DPBP. For the T2D, strong correlations between VT and DBPB workloads (r=0.853), HR (r=0.714), and VO2 (r=0.863) were found. These relationships were similar to those found for the control group (r=0.923; r=0.881; and r=0.863, respectively). [Conclusion] These results demonstrate that the DPBP enables for the prediction of AT and correlated well the VT in both the T2D and ND participants.

Effects of Exhaust Gas Dilution on the Laminar Burning Velocity of Real-World Gasoline Fuel Flame in Air

The effects of exhaust gas recirculation (EGR) on the laminar burning velocity of a commercial gasoline fuel-air mixture have been studied both numerically as well as experimentally at atmospheric pressure. The experiments have been performed using the heat flux burner method. For numerical simulation, a binary mixture of 95% iso-octane and 5% n-heptane (PRF95) is assumed to be the surrogate for the real world gasoline fuel. The numerical simulations have been carried out using a skeletal mechanism comprising of 171 species and 861 reactions for primary reference fuels. A correlation of laminar burning velocity of the commercial fuel is suggested based on experimental data for different EGR dilutions. The results show that the reduction in the laminar burning velocity caused by the EGR dilution can be recovered by the increase in the unburnt gas temperature. However, the rise in the unburnt gas temperature results in a trivial rise in the adiabatic flame temperature. The increase in the laminar burning ve...

Acute passive stretching alters ventilatory pattern during prolonged cycle exercise (882.2)

Passive stretching may induce the activation of receptors on the terminal end of group III and IV nerve fibers located within joints and muscles through mechanical and chemical stimuli. The aim of the study was to assess the effects of an acute bout of passive stretching on the ventilatory pattern during exercise. Maximum oxygen uptake (VO2max) was determined in nine participants who then performed a sustained cycle exercise of high intensity (85% of VO2max, W85) up to exhaustion, with and without previous stretching administration (on different days, in random order). During the tests metabolic and respiratory parameters were recorded breath‐by‐breath. Time to exhaustion in the W85 test was significantly shorter (−29%) with stretching. During the first 12 minutes of exercise the following parameters were significantly higher with stretching than without: VO2 (+4%), VE (+9%), respiratory muscle power (+16%) and respiratory muscle VO2 (+13%). The increase in VE was accompanied mainly by an increase in respiratory frequency rather than in tidal volume. Stretching altered the respiratory and metabolic response to exercise Whether the higher VE during exercise after stretching is a consequence of higher muscle afferent activation or higher metabolic rate, though, requires further investigation., but its effects on VE need further investigation.

Niche construction and Dreaming logic: aboriginal patch mosaic burning and varanid lizards ( Varanus gouldii ) in Australia

Anthropogenic fire is a form of ecosystem engineering that creates greater landscape patchiness at small spatial scales: such rescaling of patch diversity through mosaic burning has been argued to be a form of niche construction, the loss of which may have precipitated the decline and extinction of many endemic species in the Western Desert of Australia. We find evidence to support this hypothesis relative to one keystone species, the sand monitor lizard (Varanus gouldii). Paradoxically, V. gouldii populations are higher where Aboriginal hunting is most intense. This effect is driven by an increase in V. gouldii densities near successional edges, which is higher in landscapes that experience extensive human burning. Over time, the positive effects of patch mosaic burning while hunting overwhelm the negative effects of predation in recently burned areas to produce overall positive impacts on lizard populations. These results offer critical insights into the maintenance of animal communities in the desert, supporting the hypothesis that the current high rate of endemic species decline among small animals may be linked to the interaction between invasive species and mid-century removal of Aboriginal niche construction through hunting and patch mosaic burning.

Validity of reporting oxygen uptake efficiency slope from submaximal exercise using respiratory exchange ratio as secondary criterion.

Background. Oxygen uptake efficiency slope (OUES) is a reproducible, objective marker of cardiopulmonary function. OUES is reported as being relatively independent of exercise intensity. Practical guidance and criteria for reporting OUES from submaximal tests has not been established. Objective. Evaluate the use of respiratory exchange ratio (RER) as a secondary criterion for reporting OUES. Design. 100 healthy volunteers (53 women) completed a ramped treadmill protocol to exhaustive exercise. OUES was calculated from data truncated to RER levels from 0.85 to 1.2 and compared to values generated from full test data. Results. Mean (sd) OUES from full test data and data truncated to RER 1.0 and RER 0.9 was 2814 (718), 2895 (730), and 2810 (789) mL/min per 10-fold increase in VE, respectively. Full test OUES was highly correlated with OUES from RER 1.0 (r = 0.9) and moderately correlated with OUES from RER 0.9 (r = 0.79). Conclusion. OUES values peaked in association with an RER level of 1.0. Sub-maximal OUES values are not independent of exercise intensity. There is a significant increase in OUES value as exercise moves from low to moderate intensity. RER can be used as a secondary criterion to define this transition.

Non-linear coupling voltage of split-gate flash memory cells with additional top coupling gate

The study presents the dependence of floating gate (FG) coupling potential, V FG on the source line (SL) programming voltage, V SL of the split-gate flash memory cells with an additional top coupling gate above FG, called the `SG-TCG` cells. The mathematical analysis shows non-linear V FG against V SL behaviour of SG-TCG cells depending on the operation region of FG-MOSFETs. It is found that as the value of V SL increases, the value of V FG initially increases steeply, then gradually and finally, linearly with a lower slope. This anomalous V FG against V SL behaviour is because of the potential drop in the bulk of FG-MOSFETs by the applied V SL . The mathematical analysis, also, shows SL coupling factor (κ SL ) roll-off because of the increase in the FG-MOSFETs body potential with the increase in V SL . In addition, κ SL is shown to approach a constant value in the saturation region of FG-MOSFETs where V FG is less susceptible to supply voltage fluctuation. The mathematical analysis agrees very well with the numerical device simulation. The study, clearly, shows that in order to achieve higher shift in programme cell threshold voltage and reduce performance variability owing to supply voltage fluctuation, the target programming bias V SL of nanoscale SG-TCG cells must be higher than the saturation voltage of FG-MOSFETs.

Breath-Hold Diving

Extensive breath-hold (BH) diving imposes high pulmonary stress by performing voluntary lung hyperinflation maneuvers (glossopharyngeal insufflation, GI), hyperinflating the lung up to 50% of total lung capacity. Breath-hold durations of up to 10 min without oxygen support may also presume cerebral alterations of respiratory drive. Little is known about the long-term effects of GI onto the pulmonary parenchyma and respiratory adaptation processes in this popular extreme sport. Lung function assessments and subsequent measures of pulmonary static compliance were obtained for 5 min after GI in 12 elite competitive breath-hold divers (BHD) with a mean apnea diving performance of 6.6 yr. Three-year follow-up measurements were performed in 4 BHD. Respiratory drive was assessed in steady-state measurements for 6% and 9% CO2 in ambient air. Short-term pulmonary stress effects for static compliance during GI (13.75 L·kPa) could be confirmed in these 12 divers without exhibiting permanent changes to the lungs' distensibility (7.41 L·kPa) or lung function parameters as confirmed by the follow-up measurements and for 4 BHD after 3 yr (P>0.05). Respiratory drive was significantly reduced in these BHD revealing a characteristic breathing pattern with a significant increase in VE and mouth occlusion pressure (P0.1) between free breathing and 6% CO2, as well as between 6% CO2 and 9% CO2 (all P<0.001). BH diving with performance of GI does not permanently alter pulmonary distensibility or impair ventilatory flows and volumes. A blunted response to elevated CO2 concentrations could be demonstrated, which was supportive of the hypothesis that CO2 tolerance is a training effect due to BH diving rather than being an inherited phenomenon.

Aerobic and anaerobic threshold of Japanese male adults.

Aerobic threshold (AerT) and anaerobic threshold (AnT) were determined in 20 non-athletes (physical education majors) and 10 athletes (varsity athletes), aged 20.8-31.5 years, during incremental exercise on the cycle ergometer; workloads were increased by 0.25 Kp every 3 minutes at 50 rpm. AerT was determined using selected respiratory gas exchange parameters, i.e., non-linear increase in VE and VCO2, and peak VO2 . VE-1. AnT was estimated from break-away VE and the onset of decrease in FECO2. The reliability of the testing procedure was studied separately on 24 physical education majors. VO2 max was measured during another incremental exercise on the cycle ergometer. The mean values of VO2 max for non-athletes and athletes were 3.17 l/min (48.1 ml/kg . min) and 3.64 l/min (54.7 ml/kg . min), respectively. The test-retest correlation coefficients were 0.961 for VO2-AerT and 0.786 for VO2-AnT. The mean values of VO2-AerT and %AerT were 1.62 l/min and 51.0% for non-athletes, and 2.23 l/min and 61.9% for athletes. The mean values of VO2-AnT and %AnT were 2.09 l/min and 66.3% for non-athletes, 2.49 l/min and 69.2% for athletes.