1,687 research outputs found
Effect of co-administration of alendronate and allan sodium phosphate for the management of osteoporosis
Purpose: To study the therapeutic effect of combination of alendronate and allan sodium phosphate on osteoporosis.Methods: Patients diagnosed with osteoporosis (100) were randomly assigned to control and study groups (50 subjects/group). The control group received conventional calcium treatment (calcium carbonate D3) after surgery. They consisted of 21 males and 29 females aged 62 to 78 years. The observation group consisted of 22 males and 28 females aged 63 to 77 years (mean age = 68.90 ± 6.43 years), and were treated with sodium alendronate and allan sodium phosphate. Bone mineral density (BMD), bone pain score, clinical effectiveness and levels of calcium, phosphorus, osteocalcin, collagen N-terminal peptide (NTX) and urinary calcium/creatinine were determined using ELISA kits.Results: After 1 year of treatment, lumbar vertebral and femoral neck BMD significantly increased in both groups. The study group had significantly higher BMD than the controls (p < 0.05). Blood calcium levels increased significantly after 1 year in both groups. The treatment led to a higher level of osteocalcin in the study group than in the control group (p < 0.05). However, the treatment brought about significantly lower NTX level in the study group than in controls.Conclusion: The results indicate that combined administration of sodium alendronate and allan sodium phosphate is effective for the treatment of osteoporosis.Keywords: Osteoporosis, Allan sodium phosphate, Alendronate, Apoptosis-related factors, Calciu
Transition of stoichiometricSr2VO3FeAs to a superconducting state at 37.2 K
The superconductor Sr4V2O6Fe2As2 with transition temperature at 37.2 K has
been fabricated. It has a layered structure with the space group of p4/nmm, and
with the lattice constants a = 3.9296Aand c = 15.6732A. The observed large
diamagnetization signal and zero-resistance demonstrated the bulk
superconductivity. The broadening of resistive transition was measured under
different magnetic fields leading to the discovery of a rather high upper
critical field. The results also suggest a large vortex liquid region which
reflects high anisotropy of the system. The Hall effect measurements revealed
dominantly electron-like charge carriers in this material. The
superconductivity in the present system may be induced by oxygen deficiency or
the multiple valence states of vanadium.Comment: 5 pages, 4 figure
Superconductivity at 15.6 K in Calcium-doped Tb_{1-x}Ca_xFeAsO: the structure requirement for achieving superconductivity in the hole-doped 1111 phase
Superconductivity at about 15.6 K was achieved in Tb_{1-x}Ca_xFeAsO by
partially substituting Tb^{3+} with Ca^{2+} in the nominal doping region x =
0.40 \sim 0.50. A detailed investigation was carried out in a typical sample
with doping level of x = 0.44. The upper critical field of this sample was
estimated to be 77 Tesla from the magnetic field dependent resistivity data.
The domination of hole-like charge carriers in the low-temperature region was
confirmed by Hall effect measurements. The comparison between the calcium-doped
sample Pr_{1-x}Ca_xFeAsO (non-superconductive) and the Strontium-doped sample
Pr_{1-x}Sr_xFeAsO (superconductive) suggests that a lager ion radius of the
doped alkaline-earth element compared with that of the rare-earth element may
be a necessary requirement for achieving superconductivity in the hole-doped
1111 phase.Comment: 7 pages, 7 figure
Doping effect of Cu and Ni impurities on the Fe-based superconductor Ba0.6K0.4Fe2As2
Copper and Nickel impurities have been doped into the iron pnictide
superconductor Ba0.6K0.4Fe2As2. Resistivity measurements reveal that Cu and Ni
impurities suppress superconducting transition temperature T_c with rates of
\Delta T_c/Cu-1% = -3.5 K and \Delta T_c/Ni-1% = -2.9 K respectively.
Temperature dependence of Hall coefficient R_H of these two series of samples
show that both Cu-doping and Ni-doping can introduce electrons into
Ba0.6K0.4Fe2As2. With more doping, the sign of R_H gradually changes from
positive to negative, while the changing rate of Cu-doped samples is much
faster than that of Ni-doped ones. Combining with the results of
first-principles calculations published previously and the non-monotonic
evolution of the Hall coefficient in the low temperature region, we argue that
when more Cu impurities were introduced into Ba0.6K0.4Fe2As2, the removal of
Fermi spectral weight in the hole-like Fermi surfaces is much stronger than
that in the electron-like Fermi surfaces, which is equivalent to significant
electron doping effect. DC magnetization and the lattice constants analysis
reveal that static magnetic moments and notable lattice compression have been
formed in Cu-doped samples. It seems that the superconductivity can be
suppressed by the impurities disregard whether they are magnetic or nonmagnetic
in nature. This gives strong support to a pairing gap with a sign reversal,
like S^\pm. However, the relatively slow suppression rates of T_c show the
robustness of superconductivity of Ba0.6K0.4Fe2As2 against impurities, implying
that multi-pairing channels may exist in the system.Comment: 7 pages, 7 figure
k-semistratifiable spaces and expansions of set-valued mappings
[EN] In this paper, the concept of k-upper semi-continuous set-valued mappings is introduced. Using this concept, we give characterizations of k-semistratifiable and k-MCM spaces, which answers a question posed by Xie and Yan.Yan, P.; Hu, X.; Xie, L. (2018). k-semistratifiable spaces and expansions of set-valued mappings. Applied General Topology. 19(1):145-153. doi:10.4995/agt.2018.7883SWORD14515319
Effect of sidewall on the flame extension characteristics beneath a ceiling induced by carriage fire in a channel
Laboratory tests were firstly conducted in a reduced scale channel to investigate the conditions for flame ejections when the carriage was at the centre of the channel. The ejected flames were recorded by two cameras and the temperature inside the enclosure and on the ceiling were measured. The lower critical heat release rate (HRR) which would result in intermittent flame ejection and upper critical HRR which would lead to continuous external flame were analysed with regards to their variations with the ventilation factor. Correlations for the longitudinal and transverse flame extension lengths and flame extension area beneath the ceiling were proposed. Subsequently further experimental investigations were conducted to study the effect of sidewall constraint on flame extension by changing the position of the carriage along the transverse direction to vary the distance between the sidewall and the carriage opening, which was also systematically varied. With the decrease of the sidewall-to-opening distance, the longitudinal flame extension length was found to increase whereas the transverse flame extension length decreased. The changes are most significant when sidewall-to-opening distance was relatively small. These trends are different from those observed in previous wall-attached fires or corner fires in channels, where the flame extension length beneath the ceiling firstly increased with the decrease of sidewall-source distance, and then decreased slightly when the fire source was attached to the wall. New correlations were proposed to account for the effect of sidewall-to-opening distance for longitudinal and transverse flame extension lengths under the ceiling. They captured well the measurements for all the present cases and some published cases not used in their derivation, demonstrating the potential for fire safety engineering applications
(Sr_3Sc_2O_5)Fe_2As_2 as a possible parent compound for FeAs-based superconductors
A new compound with the FeAs-layers, namely (Sr_3Sc_2O_5)Fe_2As_2
(abbreviated as FeAs-32522), was successfully fabricated. It has a layered
structure with the space group of I4/mmm, and with the lattice constants a =
4.069 and c = 26.876 . The in-plane Fe ions construct a square
lattice which is close to that of other FeAs-based superconductors, such as
REFeAsO (RE = rare earth elements) and (Ba,Sr)Fe_2As_2. However the inter
FeAs-layer spacing in the new compound is greatly enlarged. The temperature
dependence of resistivity exhibits a weak upturn in the low temperature region,
but a metallic behavior was observed above about 60 K. The magnetic
susceptibility shows also a non-monotonic behavior. Interestingly, the
well-known resistivity anomaly which was discovered in all other parent
compounds, such as REFeAsO, (Ba,Sr)Fe_2As_2 and (Sr,Ca,Eu)FeAsF and associated
with the Spin-Density-Wave (SDW)/structural transition has not been found in
the new system either on the resistivity data or the magnetization data. This
could be induced by the large spacing distance between the FeAs-planes,
therefore the antiferromagnetic correlation between the moments of Fe ions in
neighboring FeAs-layers cannot be established. Alternatively it can also be
attributed to the self-doping effect between Fe and Sc ions. The Hall
coefficient R_H is negative but strongly temperature dependent in wide
temperature region, which indicates the dominance of electrical conduction by
electron-like charge carriers and probably a multi-band effect or a spin
related scattering effect. It is found that the magnetoresistance cannot be
described by the Kohler's rule, which gives further support to above arguments.Comment: 5 pages, 5 figures, some contents added, and one figure adde
- …