1,888 research outputs found
Monitoring serum insulin-like growth factor-I (IGF-I), IGF binding protein-3 (IGFBP-3), IGF-I/IGFBP-3 molar ratio and leptin during growth hormone treatment for disordered growth
OBJECTIVE: Serum IGF-I levels are monitored during
GH replacement treatment in adults with GH defi-
ciency (GHD) to guide GH dose adjustment and to
minimize occurrence of GH-related side-effects. This
is not routine practice in children treated with GH. The
aim of this study was to evaluate changes in (1) serum
IGF-I, IGFBP-3 and IGF-I/IGFBP-3 molar ratio, and (2)
serum leptin, an indirect marker of GH response,
during the first year of GH treatment in children with
disordered growth.
DESIGN: An observational prospective longitudinal
study with serial measurements at five time points
during the first year of GH treatment was carried out.
Each patient served as his/her own control.
PATIENTS The study included 31 patients, grouped
as (1) GHD (n=20) and (2) non-GHD (Turner syndrome
n=7; Noonan syndrome n=4), who had not previously
received GH treatment.
MEASUREMENTS: Serum IGF-I, IGFBP-3 and leptin
levels were measured before treatment and after
6 weeks, 3 months, 6 months and 12 months of GH
treatment, with a mean dose of 0.5 IU/kg/wk in GHD
and 0.7 IU/kg/wk in non-GHD groups. IGF-I, IGFBP-3
and the calculated IGF-I/IGFBP-3 molar ratio were
expressed as SD scores using reference values from
the local population.
RESULTS: In the GHD group, IGF-I SDS before treatment was lower compared with the non-GHD (-5.4 ± 2.5 vs. -1.8 ± 1.0; P < 0.001). IGF-I (-1.8 SDS ± 2.2) and IGFBP-3 (-1.1 SDS ± 0.6) levels and their molar ratios were highest at 6 weeks and remained relatively constant thereafter. In the non-GHD group, IGF-I levels increased throughout the year and were maximum at 12 months (0.3 SDS ± 1.4) while IGFBP-3 (1.1 SDS ± 0.9) and IGF-I/IGFBP-3 molar ratio peaked at 6 months. In both groups, IGF-I SDS and IGF-I/IGFBP-3 during treatment correlated with the dose of GH expressed as IU/m2/week (r-values 0.77 to 0.89; P = 0.005) but not as IU/kg/week. Serum leptin levels decreased significantly during GH treatment in the GHD (median before treatment 4.0 g/l; median after 12 months treatment 2.4 g/l; P = 0.02) but not the non-GHD (median before treatment 3.0 g/l; median after 12 months treatment 2.6 g/l). In the GHD group, serum leptin before treatment correlated with 12 month change in height SDS (r = 0.70, P = 0.02).
CONCLUSIONS: The pattern of IGF-I, IGFBP-3 and
their molar ratio during the first year of GH treatment
differed between the GHD and non-GHD groups. Calculation
of GH dose by surface area may be preferable
to calculating by body weight. As a GH dose-dependent
increase in serum IGF-I and IGF-I/IGFBP-3 may
be associated with adverse effects, serum IGF-I and
IGFBP-3 should be monitored routinely during longterm
GH treatment. Serum leptin was the only variable
that correlated with first year growth response in
GHD
Comparative Phytonutrients Analysis and Proximate Constituents of few Accessions of Nigerian and Indian Eggplant (Solanum species)
Vegetable plants contain appreciable amount of bioactive components that may provide desirable well-being merits beyond primary nutrition. It also provide major role in preventing numerous chronic diseases. Therefore, this study compared the morphological, nutritional and phytonutrients parameters of some accessions of Nigerian and Indian Eggplants in a Completely Randomized design model. The Nigerian accessions are namely: NG/MR/MAY/09/007; NGB01309 and NHGB/09/136 collected from NACGRAB, Ibadan, Nigeria while the Indian accessions are NISHA improved and PINK collected from Authorized Agency, India. The results revealed a significant difference in the germination percentage with Indian species recorded between 80 and 90% as against between 50 and 70% noted for Nigerian species. Average plant height at 90 days for India samples was 33cm, 30cm for Nisha and Pink respectively while Nigerian samples was significantly high in height (48.3cm, 21cm and 36.3cm for NG/MR/MAY/09/007, NGB01309 and NHGB/09/136 respectively). With the exception of NGB01309 other Nigerians samples were superior (P<0.05) to the Indian sample. The phytochemicals of the leaves and fruits (Flavonoid, Cardiac glycosides, Alkaloids, Saponins, Tannins and Phytates) reported herein was greater in all Nigerian samples. Nutritionally, the Indian samples were superior in all the parameters (% Starch, Protein and Crude fibre) examined. The availability of more phytonutrients in Nigerian accession relates to more and better prevention of cardiovascular, stroke, Alzheimer and cancer diseases as well as ageing. In conclusion the accessions showed their potentials as a good source for use as nutraceuticals so as to promote general health, control symptoms and check malignant diseases. Keywords: Solanum species, phytochemicals, morphology, nutritional valu
Numerical computation of tyre radiaion noise: a comparative study of different techniques
Increasingly stringent noise regulations concerning automotive vehicles particularly in Europe are forcing Tyre manufacturers as well as the automotive manufacturers to reduce radiated noise. With the future moving towards electric/hybrid vehicles, the ever present tyre noise will become more dominant. Even in the case of automotive engines running on fossil fuels, tyre noise dominates above speeds of 40 Km/h. Understanding the causes of tyre noise is the first step towards finding engineering solutions to reduce it. Numerical modelling can help the tyre engineer in understanding the causes of tyre-road noise with a design tool.
In the present work, the noise radiated by the tyre surface is computed numerically using three different computational techniques. Both the time domain approach and the frequency domain approaches are used and the results are compared. The input structural vibrations are computed in ABAQUS (Ref. 1) and the results are then imported to LMSVirtual.Lab (Ref. 2) for further acoustic computations. As the main focus of this work is on the acoustic computations, only a brief description of the process involved in the structural vibration calculations is provided. In the present work, the “Horn effect” is inherently captured in the acoustic simulations. Two model tyres, viz., with tread pattern and with circumferential grooves is evaluated. The presence of tread leads to the phenomenon of stick slip and stick snap mechanisms contributing to the overall tyre noise. In addition, the motion of air through the grooves causes air pumping noise.
It is to be noted that the structural vibration computations were performed on a rotating tyre that translated on a stationary road. In other words, the tyre underwent rotational as well as translational displacement. The acoustic computations are however performed on a stationary tyre model. One of the challenges addressed in the present work is the conversion of transient vibration results on a stationary acoustic mesh. The surface accelerations, required as boundary conditions, are converted to the frequency domain by the Fast Fourier Transformation for the Harmonic computations. The details of the structural models as well as the acoustic models and a short description of the techniques used in the computations of the radiated noise are described in the next section
Ferromagnetic/III-V semiconductor heterostructures and magneto-electronic devices
The interface magnetic and electronic properties of two Fe/III-V semiconductor systems, namely Fe/GaAs and Fe/InAs, grown at room temperature have been studied. A "magnetic interface", which is essential for the fabrication of magneto-electronic (ME) devices, was realized in both Fe/GaAs and Fe/InAs systems with suitable substrate processing and growth conditions. Furthermore, Fe/InAs was shown to have favorable interface electronic properties as Fe forms a low resistance ohmic contact on InAs. Two prototypes of ME device based on Fe/InAs are also discussed
Decoherence in rf SQUID Qubits
We report measurements of coherence times of an rf SQUID qubit using pulsed
microwaves and rapid flux pulses. The modified rf SQUID, described by an
double-well potential, has independent, in situ, controls for the tilt and
barrier height of the potential. The decay of coherent oscillations is
dominated by the lifetime of the excited state and low frequency flux noise and
is consistent with independent measurement of these quantities obtained by
microwave spectroscopy, resonant tunneling between fluxoid wells and decay of
the excited state. The oscillation's waveform is compared to analytical results
obtained for finite decay rates and detuning and averaged over low frequency
flux noise.Comment: 24 pages, 13 figures, submitted to the journal Quantum Information
Processin
Nonlinear Transport in a Quantum Point Contact due to Soft Disorder Induced Coherent Mode Mixing
We show that the coherent mixing of different transverse modes, due to
forward scattering of carriers by soft impurity- or boundary potentials leads
to a nonlinear, asymmetric current response of quantum point contacts (QPC).
The oscillating contribution to the current is sensitive both to driving
voltage and to gate voltage in direct analogy to the electrostatic
Aharonov-Bohm effect.
Our calculations are in a good agreement with recent experimental data
showing small-scale conductivity nonlinearities and asymmetry in QPC.Comment: 4 pages, 2 figures (availiable upon request), REVTEX, Applied Physics
Report 93-4
Bias and temperature dependence of the 0.7 conductance anomaly in Quantum Point Contacts
The 0.7 (2e^2/h) conductance anomaly is studied in strongly confined, etched
GaAs/GaAlAs quantum point contacts, by measuring the differential conductance
as a function of source-drain and gate bias as well as a function of
temperature. We investigate in detail how, for a given gate voltage, the
differential conductance depends on the finite bias voltage and find a
so-called self-gating effect, which we correct for. The 0.7 anomaly at zero
bias is found to evolve smoothly into a conductance plateau at 0.85 (2e^2/h) at
finite bias. Varying the gate voltage the transition between the 1.0 and the
0.85 (2e^2/h) plateaus occurs for definite bias voltages, which defines a gate
voltage dependent energy difference . This energy difference is
compared with the activation temperature T_a extracted from the experimentally
observed activated behavior of the 0.7 anomaly at low bias. We find \Delta =
k_B T_a which lends support to the idea that the conductance anomaly is due to
transmission through two conduction channels, of which the one with its subband
edge \Delta below the chemical potential becomes thermally depopulated as the
temperature is increased.Comment: 9 pages (RevTex) with 9 figures (some in low resolution
3D-HST+CANDELS : the evolution of the galaxy size-mass distribution since z=3
Spectroscopic+photometric redshifts, stellar mass estimates, and rest-frame colors from the 3D-HST survey are combined with structural parameter measurements from CANDELS imaging to determine the galaxy size-mass distribution over the redshift range 0 < z < 3. Separating early- and late-type galaxies on the basis of star-formation activity, we confirm that early-type galaxies are on average smaller than late-type galaxies at all redshifts, and we find a significantly different rate of average size evolution at fixed galaxy mass, with fast evolution for the early-type population, R eff∝(1 + z)–1.48, and moderate evolution for the late-type population, R eff∝(1 + z)-0.75Peer reviewedFinal Accepted Versio
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