N-doped TiO
2
nanoparticles have been prepared by continuous or batch treatment of the colloidal TiO
2
nanoparticles under hydrothermal conditions with formamide, nitric acid, ammonia or ...triethylamine. The optical absorption tail of the obtained photocatalysts near the band gap extended to the visible region around
λ
= 500 nm. The efficiency of nitrogen doping was strongly dependent on the kind of nitrogen compounds, treatment method as well as treatment temperature. The most effective N-doping could be accomplished by the batch treatment with a small amount of triethylamine, which showed the efficient photocatalytic activity for both the reduction of Ag
+
ions and the degradation of methylene blue under visible light irradiation.
The monolayer assemblies incorporating the J-aggregates of oxacyanine dye, N,N‘-dioctadecyloxacyanine perchlorate (S9), and thiacyanine dye, N,N‘-dioctadecylthiacyanine perchlorate (S11), S9(J) + ...S11(J), have been fabricated by the Langmuir−Blodgett (LB) technique. The mole fraction X of S11, X = S11/(S9 + S11), was varied from 0 to 1. Steady-state absorption spectra, fluorescence spectra, and picosecond fluorescence decay curves of the monolayer assemblies have been measured. Spectroscopic properties of the monolayer assemblies incorporating the individual dye aggregates, S9 J-aggregate (S9(J), X = 0) or S11 J-aggregate (S11(J), X = 1), are characterized by a distinct J-band and resonance fluorescence at λab = 403 nm and λem = 403 nm for S9(J) and λab = 456 nm and λem = 463 nm for S11(J). On the other hand, absorption spectra of the S9(J) + S11(J) assemblies for X = 0.1−0.9 display two absorption bands, a shorter wavelength one and a longer wavelength one, whose peak positions are blue-shifted from those of the corresponding J-bands of the S9 J-aggregate and the S11 J-aggregate, respectively. Furthermore, fluorescence spectra are characterized by a single band (longer wavelength fluorescence) which is somewhat blue-shifted from the resonance fluorescence of the S11 J-aggregate. The fluorescence lifetimes of the S11 J-aggregate and isolated S11 molecules in LB films appear to be τ = 110 and 1900 ps, respectively, while the fluorescence lifetime of the longer wavelength fluorescence of the S9(J) + S11(J) assemblies takes practically a constant value of τ = 170−180 ps for X = 0.2−0.8. These observations would indicate that S9 and S11 molecules in the S9(J) + S11(J) assembly can form a specific mixed aggregate distinct from the individual S9 and S11 J-aggregates. From detailed considerations of the former works on luminescence properties of the S9 J-aggregate doped with isolated S11 molecules, as well as the mosaic-type mixed J-aggregate (M-aggregate) composed of a certain thiacyanine dye, 3,3‘-disulfopropyl- 5,5‘-dichlorothiacyanine sodium salt, and thiacarbocyanine dye, meso-substituted 3,3‘-disulfopropyl-5,5‘-dichlorothiacarbocyanine potassium salt, it is suggested that S9 and S11 can form a homogeneous aggregate of the persistence type (HP-aggregate). The HP-aggregate is distinguished from the M-aggregate because it is characterized by homogeneous mixing of two component dyes and persistence of two absorption bands.
Formation and aggregation of photolytic silver nanoparticles at the surface of silver salt of carboxymethylcellulose films (CMCAg films) have been investigated. Detailed X-ray photoelectron ...spectroscopy (XPS) study and field emission type scanning electron microscopy (FE-SEM) observation have been carried out to characterize silver nanoparticles at the film surface. When the CMCAg films were irradiated with UV light in wet air at room temperature for 30-60 min, silver nanoparticles of ca. 10 nm size were formed at the irradiated surface. According to the FE-SEM observation, the growth of the particle diameter and aggregation of nanoparticles took place after prolonged irradiation, and finally, the irradiated side of the film surface was densely covered with the silver nanoparticles of ca. 35 nm size. Chemical composition analysis by the XPS measurements has confirmed the increase in the atomic concentration of silver with irradiation time. It is suggested that silver atoms and clusters can move in the film and precipitate at the irradiated surface.PUBLICATION ABSTRACT
The monolayer assemblies incorporating two kinds of unsymmetric merocyanine dye aggregates (MC(X)/MC(Y), X = O, S, Se) have been fabricated by the Langmuir–Blodgett technique. The absorption spectra ...of the Langmuir–Blodgett films were measured in wide temperature range of
T
=
6.0–293
K. The absorption spectra of the MC(O)/MC(S) and the MC(O)/MC(Se) assemblies bear two absorption bands which are assigned to the MC(O) aggregate and the MC(S) J-aggregate or the MC(Se) J-aggregate, respectively. In contrast, the absorption spectrum of the MC(S)/MC(Se) assembly shows a single absorption band of the mixed J-aggregate. From detailed considerations of the low-energy tail of absorption spectra based on the Urbach–Martienssen rule, together with other spectroscopic properties, it is concluded that the MC(O)/MC(S) or the MC(O)/MC(Se) assembly forms a mosaic aggregate. The MC(S)/MC(Se) assembly can form high-quality homogeneous aggregate of amalgamation type.
The photoreduction of Ag
+ ions at the surface of colloidal TiO
2 nanoparticles has been investigated. Irradiation of an aqueous solution containing TiO
2 and Ag
+ ions with near-UV light brings ...about the growth of a sharp absorption band of colloidal silver in absorption spectrum. The photoreduction of Ag
+ ions by TiO
2 is optically sensitized by a simple cyanine dye, 3,3′-disulfopropyl-5,5′-dichloro-thiacyanine sodium salt (TC). TC molecules are adsorbed at the surface of TiO
2 nanoparticles in the form of the J-aggregate (JA). Visible-light irradiation of the solution containing TiO
2, Ag
+ ions, and TC causes the growth of a broad absorption band of the colloidal silver and the decrease of whole absorption bands of TC. Experimental results have been interpreted in terms of electronic energy levels of the colloidal silver and the TC aggregate, as well as energy bands of TiO
2. In the sensitized photoreduction, TiO
2 could play the role of a medium to facilitate efficient electron transfer from the excited TC aggregate to Ag
+ ions adsorbed at the surface.
The clinical outcomes of balloon kyphoplasty (BKP) for split-type osteoporotic vertebral fractures (OVF) are poor. These may be owing to the vertebral body bifurcating anteriorly and posteriorly when ...a load is applied and the filled cement being unstable. We report the usefulness of BKP combined with pediculoplasty using cannulated screws (vertebra-pediculoplasty) for OVF with a risk of cement dislodgement.
Between April 2020 and February 2021, this surgery was performed on 10 patients with split-type and delayed-union OVF. The diagnosis was made using imaging findings on preoperative computed tomography or intraoperative images during balloon inflation. Early postoperative ambulatory rehabilitation was performed, and clinical outcomes were evaluated.
Early pain relief was obtained in all patients. The stability of the fractured vertebrae was demonstrated using both supine and seated radiographs from the early postoperative period, and good clinical results were obtained. The cement in this surgery was stabilized using a cannulated screw in the vertebral body, anteroposteriorly, and craniocaudally. The cement mass integrated with the cannulated screw was stabilized with the vertebral lamina and pedicle as a stopper.
Vertebra-pediculoplasty could be an effective method for managing OVF with a high risk of cement dislodgement, which has been difficult to treat using conventional BKP.
The layer-by-layer alternate assemblies incorporating two kinds of cyanine dyes have been fabricated by alternately adsorbing a cationic polyelectrolyte and anionic cyanine dyes on the quartz plate. ...A thiacyanine dye (dye I) was employed as the donor and two kinds of thiacarbocyanine dye having a meso-alkyl groupm-ethyl (dye II), m-methyl (dye III)as the acceptor. The mole fraction of the acceptor in the mixed J-aggregate, χ, was varied from 0 to 1. It is confirmed that these dye combinations form the mixed J-aggregate in the alternate assemblies. From steady-state fluorescence spectra of the molecular assemblies, excitation energy transfer from the donor J-aggregate to the acceptor J-aggregate is observed, whose kinetics obeys the Stern−Volmer relationship. The experimentally determined rate constant of energy transfer, k ET, is fairly large, indicating efficient energy transfer due to exciton migration through the donor J-aggregate. The relative fluorescence quantum yield and the fluorescence lifetime of the acceptor aggregate decrease with increasing χ, implying the considerable self-quenching of acceptor fluorescence. The relative change of the coherent size of the dye II aggregate has been estimated from the J-band line width and the radiative decay rate constant. It is found that the coherent size of the dye II aggregate is increased by a factor of 4−5 with increasing χ from 0.008 to 1.
Abstract
This case report describes a 13-year-old female patient with adolescent idiopathic scoliosis (AIS) and flat back who experienced progressive kyphotic deformity after implant removal despite ...obtaining physiological alignment postoperatively. The patient underwent multiple surgeries, and a late-developing infection complicated her treatment course. Despite hard bracing to prevent kyphotic change, the kyphosis progressed to 74° within a year after implant removal, leading to a decrease in patient height and back pain. Revision surgery was eventually necessary. Possible factors for the kyphotic progression include injury to paraspinal back muscles due to multiple surgeries or insufficient bony fusion from late-developing infection. This case highlights the importance of thorough evaluation and follow-up for optimal patient outcomes after implant removal in AIS patients, particularly those with flat back.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
UV absorption spectra of benzene have been measured over the wide range of temperature and pressure from the ambient state to the supercritical state (
T
=
400 °C and
P
=
40 MPa). The analysis of the ...spectral shift of benzene in water relative to that in the gas indicates that at
T
=
380 and 390 °C the local solvent density around benzene is likely to be depressed below the bulk density for densities near the critical density. It is found that π-hydrogen bond between benzene and water becomes evident with lowering temperature below
T
=
340 °C.
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