Faced with large humanitarian emergencies like the earthquakes in Haiti and Japan, aid agencies have to decide how to collect money for their relief work. They can either decide to establish a special fund for the emergency and allow for earmarked donations or they can only allow for unearmarked donations. In this paper, we analyze impacts of this decision on donors, aid agencies, and policy makers. To this end, we compare two prevalent fundraising modes using optimization models: fundraising with the option of earmarking donations and fundraising without an earmarking option. In the earmarked case, we consider a new fundraising challenge, excessive funds raised for certain disaster relief projects. We find that desirable fundraising modes for donors, aid agencies, and policy makers differ depending on levels of several parameters, including an aid agency’s utility of a dollar raised, the fundraising cost factor, and donors’ unit utility of donations. Allowing for earmarking leads to a lower overall fundraising cost percentage. For emergencies with strong media attention and donor interest, allowing for earmarking of donations is likely to reduce fundraising activities of organizations with low fundraising costs, while it is likely to encourage fundraising activities among organizations with high fundraising costs. 相似文献
We have developed a novel method to induce spontaneous hyaline cartilage regeneration in vivo for a large osteochondral defect by implanting a plug made from a double‐network hydrogel composed of poly(2‐acrylamido‐2‐methylpropanesulfonic acid) and poly(N,N′‐dimethylacrylamide) at the bottom of the defect, leaving the cavity vacant. In cells regenerated in the treated defect, type‐2 collagen, Aggrican, and SOX9 mRNAs were highly expressed and the regenerated matrix was rich in proteoglycan and type‐2 collagen at 4 weeks. This fact gave a significant modification to the commonly established concept that hyaline cartilage tissue cannot regenerate in vivo. This study prompted an innovative strategy in the field of joint surgery to repair an osteochondral defect using an advanced, high‐function hydrogel.
Several organosilicon compounds bearing a 2-(phenylazo)phenyl group were synthesized from the corresponding chlorosilanes and 2-lithioazobenzene prepared by halogen-lithium transmetalation of 2-iodoazobenzene. Their structures were determined by (1)H, (13)C, (19)F, and (29)Si NMR spectra, UV-vis spectra, and X-ray crystallographic analyses. In the UV-vis spectra, silyl groups caused red shifts of both the n-pi and pi-pi transitions of the azo group compared with the transitions of the unsubstituted azobenzene. The E-isomers of the fluorosilanes showed an intramolecular interaction between a nitrogen atom of the azo group and the silicon atom, leading their intermediate structures between a distorted trigonal bipyramidal structure and a tetrahedral structure around the silicon atoms, which were revealed by the X-ray crystallographic analyses and the NMR spectra. On the other hand, silanes without fluorine atoms showed tetrahedral structures in the absence of such an interaction. The photoirradiation of the E-isomers of the fluorosilanes afforded reversibly the corresponding Z-isomers in good yields. The silicon atoms of the Z-isomers were found to be tetracoordinate in the absence of Si-N interactions by the (29)Si NMR spectra. The coordination numbers of the silicon atom of the fluorosilanes were reversibly switched between four and five by photoirradiation. These properties were compared to those of a tetrafluoro[2-(phenylazo)phenyl]silicate. 相似文献
Suramin is an activator of ryanodine receptors and competitively binds to the calmodulin-binding site. In addition, S100A1 and calmodulin compete for the same binding site on ryanodine receptors. We therefore studied the effects of suramin on protein phosphatase 5 (PP5) and S100-activated PP5. In the absence of S100 proteins, suramin bound to the tetratricopeptide repeat (TPR) domain of PP5 and activated the enzyme in a dose-dependent manner. In the presence of S100A2/Ca2+, lower concentrations of suramin dose-dependently inhibited PP5 activity as an S100 antagonist, whereas higher concentrations of suramin reactivated PP5. Although the C-terminal fragment of heat shock protein 90 (HspC90) also weakly activated PP5, the binding site of suramin and HspC90 may be different, and addition of suramin showed no clear effect on the phosphatase activity of PP5. Similar biphasic effects of suramin were observed with S100A1-, S100B- or S100P-activated PP5. However, the inhibitory effects of lower concentrations of suramin on S100A6-activated PP5 are weak and high concentrations of suramin further activated PP5. SPR and the cross-linking study showed inhibition of the interaction between S100 protein and PP5 by suramin. Our results revealed that suramin is a novel PP5 activator and modulates S100-activated PP5 activity by competitively binding to the TPR domain. 相似文献
Periodontal disease is a serious dental problem because it does not heal naturally and leads to tooth loss. In periodontal disease, inflammation at periodontal tissue is thought as predominant, and its effect against tooth itself remains unclear. In this study, we applied matrix-assisted laser desorption/ionization imaging mass spectrometry (IMS) to teeth for the first time. By comparing anatomical structure of tooth affected with periodontal disease with normal ones, we analyzed traces of the disease on tooth. We found signals characteristic of enamel, dentin, and dental pulp, respectively, in mass spectra obtained from normal teeth. Ion images reconstructed using these signals showed anatomical structures of the tooth clearly. Next, we performed IMS upon teeth of periodontal disease. Overall characteristic of the mass spectrum appeared similar to normal ones. However, ion images reconstructed using signals from the tooth of periodontal disease revealed loss of periodontal ligament visualized together with dental pulp in normal teeth. Moreover, ion image clearly depicted an accumulation of signal at m/z 496.3 at root surface. Such an accumulation that cannot be examined only from mass spectrum was revealed by utilization of IMS. Recent studies about inflammation revealed that the signal at m/z 496.3 reflects lyso-phosphatidylcholine (LPC). Infiltration of the signal is statistically significant, and its intensity profile exhibited the influence has reached deeply into the tooth. This suggests that influence of periodontal disease is not only inflammation of periodontal tissue but also infiltration of LPC to root surface, and therefore, anti-inflammatory treatment is required besides conventional treatments. 相似文献
We observed changing supramolecular structures of stilbene-α-cyclodextrin (StiO-α-CD) by photoirradiation and migration. Stilbene derivatives show photoinduced isomerization under irradiation with λ = 340 nm to give 2-cis-StiO-α-CD and with λ = 254 nm to give 2-trans-StiO-α-CD. Photoisomerization of StiO-α-CD shows the photostationary state during 30 min. 2D NMR and diffusion coefficient studies revealed that 2-trans-StiO-α-CD forms a double-threaded dimer but 2-cis-StiO-α-CD changes to a supramolecular oligomer by photoirradiation. We found that the mutual migration of a stilbene group (StiO) on α-CD occurs under neutral conditions. The StiO group of α-CD (StiO-α-CD) moves between the C2 and C3 positions on the secondary hydroxyl group of StiO-α-CD (the wider rim of α-CD) to give 3-trans-StiO-α-CD. 3-trans-StiO-α-CD forms a supramolecular oligomer, whereas 3-cis-StiO-α-CD changes to a double-threaded dimer, indicating that 3-StiO-α-CDs gives the opposite results in the supramolecular structures of 2-StiO-α-CDs. The thermal isomerization (migration) is very slow. It takes about 300 h to reach the equilibrium state. Moreover, the migration rate constant (k(trans3→2)) of the trans-StiO group from the C3 position to the C2 position of α-CD is faster than k(trans2→3) from the C2 position to the C3 position of α-CD. On the other hand, k(cis2→3) of the cis-StiO group from the C2 position to the C3 position of α-CD is faster than k(cis3→2) from the C3 position to the C2 position, meaning k(cis2→3) > k(cis3→2), which is the opposite result for k(trans3→2) > k(trans2→3). The formation of a stable double-threaded dimer would suppress the migration of the StiO group of StiO-α-CDs in aqueous solutions. 相似文献
We are developing a high-resolution small angle neutron scattering instrument for very cold neutrons (VCN). Our concept includes a magnetic lens for focusing of the beam at the detector plane. The lens consists of one permanent-magnet sextupole array rotating outside another stationary sextupole array, to focus a pulsed white beam of neutrons. Thus the instrument operates in time of flight mode. The prototype magnetic lens has a bore of 15 mm diameter and length of 66 mm, producing a magnetic field gradient oscillating from 1.5×104 to 5.9×104 T/m2, with frequency ≤25 Hz. A torque-canceling magnet around the lens suppresses the torque of rotation from the outer array to 1/3.We have demonstrated the performance of the lens, over wavelength range from 30 to 48 Å, on the PF2-VCN beam line at the Institut Laue-Langevin, France. The focused beam image was the same size as the source, without chromatic aberration, with focal length of 1.14 m. We also studied the performance of this configuration for high-resolution SANS, in a compact geometry (just 5 m long). The measurable q range of this system was 0.009 Å−1≤q≤0.3 Å−1 or 0.004 Å−1≤q≤0.08 Å−1 for sample to detector distances of 100 and 465 mm, respectively. Here, we present the results of our lens characterization study along with the SANS results on a tri-block copolymer (F127 Pluronic) and on a stretched polymer blend (with the Shish-Kebab structure). 相似文献
The nature of the chiral phase transition in lattice QCD is studied for the cases of 2, 3 and 6 flavors with degenerate Wilson quarks, mainly on a lattice with the temporal direction extensionNt=4. We find that the chiral phase transition is continuous for the case of 2 flavors, while it is of first order for 3 and 6 flavors. 相似文献