Age-adjusted 5-factor modified frailty index as a valuable tool for patient selection in bilateral simultaneous total knee arthroplasty.

Although bilateral simultaneous total knee arthroplasty (BSTKA) is an effective treatment for bilateral knee osteoarthritis, safety concerns and lack of precise patient selection criteria persist. The purpose of this retrospective study was to determine the complication rate and the role of frailty in patient selection for BSTKA. We analyzed data from 434 patients who underwent BSTKA between February 2012 and January 2021, examining demographic factors and preoperative blood test results. Complications occurred in 77 patients (18%), with anemia requiring transfusion being the most common (26 patients, 5.9%). In the univariate analysis, age ≥ 75 years, age-adjusted Charlson Comorbidity Index ≥ 5, age-adjusted 5-factor modified Frailty Index (aamFI-5) ≥ 3, hemoglobin ≤ 11.0 g/dL, albumin ≤ 3.5 g/dL, estimated glomerular filtration rate < 45 ml/dl/1.73 m2, and D-dimer ≥ 2.0 µg/mL contributed to postoperative complications (p < 0.05). Multivariate analysis identified aamFI-5 ≥ 3 as an independent risk factor (p = 0.002). Our findings underscore the practical utility of aamFI-5 in predicting complications after BSTKA, providing valuable guidance to surgeons in the selection of BSTKA candidates and ultimately improving clinical outcomes.

Adjacent vertebral fractures in the lumbar and thoracic spine after balloon kyphoplasty: A finite element analysis.

The purpose of the present study was to mechanically verify after vertebral augmentation (AVA) scores using a finite element method (FEM) with accurate material constants of balloon kyphoplasty (BKP) cement. Representative cases with AVA scores of 1 (case 1), 3 (case 2), and 5 (case 3) among patients with vertebral body fractures who underwent BKP were analyzed. A FEM model consisting of 5 vertebral bodies was created, including the injured vertebral body in each case. The amount of displacement for each load (up to 4000 N) between the upper and lower vertebral bodies of each model was measured. Young modulus of the BKP cement was calculated from actual measurements using the EZ-Test EZ-S (Shimadzu Corporation, Kyoto, Japan). In all cases, the number of shell elements (209,296-299,876), solid elements (1913,029-2417,671), and nodes (387,848-487,756) were similar, indicating that FEM modeling was comparable among the cases. Young modulus of BKP cement, calculated using EZ-Test EZ-S, was 572 MPa. Fractures were detected by compressive forces of 3300 N (upper) and 3300 N (lower), 3000 N (upper) and 3100 N (lower), and 1200 N (upper) and 1200 N (lower) in cases 1, 2, and 3, respectively. The AVA scoring system was mechanically verified using the accurate material constants of BKP cement. A multicenter survey and external validation are therefore required for the clinical implementation of the AVA score.

The first case of methotrexate-associated lymphoproliferative disorder in the sacrum: a case report.

Methotrexate (MTX) is a drug used for treating rheumatoid arthritis. Recently, the reported incidence of methotrexate-associated lymphoproliferative disease (MTX-LPD) has increased, especially in Japan. Extranodal involvement is observed in half of MTX-LPD cases. However, only a few spinal lesions have been reported, with none in the sacrum. Additionally, Epstein-Barr virus (EBV) infection has also been implicated in the pathogenesis of MTX-LPD. Herein, we describe the case of a 74-year-old woman with MTX-LPD in the sacral spine who complained of severe back pain and nocturnal pain. Radiographs revealed a tumour on the right wing of the sacrum and a positive EBV immunoglobulin G antibody titre. MTX-LPD was suspected based on imaging findings and a history of MTX administration. A pathological examination was performed on the CT-guided biopsy specimen. The histopathological diagnosis was MTX-LPD, and MTX was discontinued. Three months after MTX administration ended, the tumour tended to shrink, and 1 year later, significant tumour shrinkage was observed. This experience suggests that MTX-LPD can be treated by discontinuing MTX administration. Therefore, early and accurate diagnosis is required, as is avoiding unnecessary treatment such as surgery. MTX-LPD should be considered, especially in spinal origin tumours in EBV-infected patients on MTX.

Understanding the reaction mechanism and kinetics of photocatalytic oxygen evolution on CoOx-loaded bismuth vanadate.

Photocatalytic water splitting for green hydrogen production is hindered by the sluggish kinetics of oxygen evolution reaction (OER). Loading a co-catalyst is essential for accelerating the kinetics, but the detailed reaction mechanism and role of the co-catalyst are still obscure. Here, we focus on cobalt oxide (CoOx) loaded on bismuth vanadate (BiVO4) to investigate the impact of CoOx on the OER mechanism. We employ photoelectrochemical impedance spectroscopy and simultaneous measurements of photoinduced absorption and photocurrent. The reduction of V5+ in BiVO4 promotes the formation of a surface state on CoOx that plays a crucial role in the OER. The third-order reaction rate with respect to photohole charge density indicates that reaction intermediate species accumulate in the surface state through a three-electron oxidation process prior to the rate-determining step. Increasing the excitation light intensity onto the CoOx-loaded anode improves the photoconversion efficiency significantly, suggesting that the OER reaction at dual sites in an amorphous CoOx(OH)y layer dominates over single sites. Therefore, CoOx is directly involved in the OER by providing effective reaction sites, stabilizing reaction intermediates, and improving the charge transfer rate. These insights help advance our understanding of co-catalyst-assisted OER to achieve efficient water splitting.

Highly selective CO2 electrolysis in aqueous media by a water-soluble cobalt dimethyl-bipyridine complex.

A water-soluble Co complex with dimethyl-bipyridine ligands reduced CO2 to CO electrochemically with almost 100% selectivity at -0.80 V vs. NHE in an aqueous medium (pH 6.8) without an organic solvent. The reaction overpotential was 270 mV. A possible CO formation mechanism was discussed based on experiments and calculations.

CH4 Synthesis from CO2 and H2O of an Electron Source over Rh-Ru Cocatalysts Loaded on NaTaO3:Sr Photocatalysts.

CO2 reduction as an artificial photosynthetic system is a promising technology to produce green energies and chemicals because it uses light energy to convert H2O and CO2 into valuable products such as CO, HCOOH, CH3OH, CH4, and preferably higher hydrocarbons. In photocatalytic reduction, water should be used as hydrogen and electron sources for CO2 reduction. Moreover, CH4 formation is an attractive and challenging topic because of the eight-electron-reducing product of CO2. Herein, we report the development of a new Rh-Ru cocatalyst decorated on an alkaline earth-doped NaTaO3 surface for the photocatalytic CO2 reduction to form CH4 using water as an electron donor. CH4 was obtained by a photocatalytic "uphill" reaction of CO2 reduction using Rh-Ru cocatalyst-loaded NaTaO3:Sr, water, and CO2 in an aqueous suspension system. About 10% of a selectivity (electronic efficiency) was obtained for CH4 formation under ambient conditions accompanied with O2 evolution of the oxidation product of H2O.

Carbon Nitride Loaded with an Ultrafine, Monodisperse, Metallic Platinum-Cluster Cocatalyst for the Photocatalytic Hydrogen-Evolution Reaction.

For the realization of a next-generation energy society, further improvement in the activity of water-splitting photocatalysts is essential. Platinum (Pt) is predicted to be the most effective cocatalyst for hydrogen evolution from water. However, when the number of active sites is increased by decreasing the particle size, the Pt cocatalyst is easily oxidized and thereby loses its activity. In this study, a method to load ultrafine, monodisperse, metallic Pt nanoclusters (NCs) on graphitic carbon nitride is developed, which is a promising visible-light-driven photocatalyst. In this photocatalyst, a part of the surface of the Pt NCs is protected by sulfur atoms, preventing oxidation. Consequently, the hydrogen-evolution activity per loading weight of Pt cocatalyst is significantly improved, 53 times, compared with that of a Pt-cocatalyst loaded photocatalyst by the conventional method. The developed method is also effective to enhance the overall water-splitting activity of other advanced photocatalysts such as SrTiO3 and BaLa4 Ti4 O15 .

Examination of photocatalytic Z-scheme system for overall water splitting with its electronic structure.

Although the solar-to-hydrogen (STH) conversion efficiency of a photocatalytic Z-scheme system for overall water-splitting with a solid-state electron mediator composed of a hydrogen evolution cocatalyst (HEC) nanoparticles/hydrogen evolution photocatalyst (HEP) particle layer with an Rh,La-codoped SrTiO3/conductor with an Au/oxygen evolution photocatalyst (OEP) particle layer with Mo-doped BiVO4/oxygen evolution cocatalyst (OEC) nanoparticles reached the highest value (1.1%) in 2016, it was still insufficient for practical application, resulting in a proposal in a previous paper to develop HEP and OEP particles with longer wavelength absorption edges. While progress has been rather slow since then, the Z-scheme system has been analyzed in this paper from a new point of view, i.e., the electronic structure of the system on the basis of solid-state physics, in order to seek for new ideas to enhance its STH conversion efficiency. In addition to the proposal in the previous paper, new ideas in this paper include the formation of a built-in potential to enhance electron (positive hole) transfer from the HEP (OEP) to the HEC (OEC) by putting positive (negative) charges on the HEC (OEC) nanoparticles, enhancement of the reduction (oxidation) of water by an electron (a positive hole) transferred from the HEP (OEP) to the HEC (OEC) by using the quantum-size effect of HEC and OEC nanoparticles, enhancement of the transfer of a photo-created positive hole (electron) from the HEP (OEP) to the conductor by controlling the Schottky barrier between them, and enhancement of the movement of electronic charge carriers together with depression of their recombination in highly doped HEP and OEP particles by the use of ionic relaxation processes in the particles.

Photocatalytic Overall Water Splitting Under Visible Light Enabled by a Particulate Conjugated Polymer Loaded with Palladium and Iridium.

Polymer photocatalysts have received growing attention in recent years for photocatalytic hydrogen production from water. Most studies report hydrogen production with sacrificial electron donors, which is unsuitable for large-scale hydrogen energy production. Here we show that the palladium/iridium oxide-loaded homopolymer of dibenzo[b,d]thiophene sulfone (P10) facilitates overall water splitting to produce stoichiometric amounts of H2 and O2 for an extended period (>60 hours) after the system stabilized. These results demonstrate that conjugated polymers can act as single component photocatalytic systems for overall water splitting when loaded with suitable co-catalysts, albeit currently with low activities. Transient spectroscopy shows that the IrO2 co-catalyst plays an important role in the generation of the charge separated state required for water splitting, with evidence for fast hole transfer to the co-catalyst.

CO2 Reduction Using Water as an Electron Donor over Heterogeneous Photocatalysts Aiming at Artificial Photosynthesis.

Photocatalytic and photoelectrochemical CO2 reduction of artificial photosynthesis is a promising chemical process to solve resource, energy, and environmental problems. An advantage of artificial photosynthesis is that solar energy is converted to chemical products using abundant water as electron and proton sources. It can be operated under ambient temperature and pressure. Especially, photocatalytic CO2 reduction employing a powdered material would be a low-cost and scalable system for practical use because of simplicity of the total system and simple mass-production of a photocatalyst material.In this Account, single particulate photocatalysts, Z-scheme photocatalysts, and photoelectrodes are introduced for artificial photosynthetic CO2 reduction. It is indispensable to use water as an electron donor (i.e., reasonable O2 evolution) but not to use a sacrificial reagent of a strong electron donor, for achievement of the artificial photosynthetic CO2 reduction accompanied by ΔG > 0. Confirmations of O2 evolution, a ratio of reacted e- to h+ estimated from obtained products, a turnover number, and a carbon source of a CO2 reduction product are discussed as the key points for evaluation of photocatalytic and photoelectrochemical CO2 reduction.Various metal oxide photocatalysts with wide band gaps have been developed for water splitting under UV light irradiation. However, these bare metal oxide photocatalysts without a cocatalyst do not show high photocatalytic CO2 reduction activity in an aqueous solution. The issue comes from lack of a reaction site for CO2 reduction and competitive reaction between water and CO2 reduction. This raises a key issue to find a cocatalyst and optimize reaction conditions defining this research field. Loading a Ag cocatalyst as a CO2 reduction site and NaHCO3 addition for a smooth supply of hydrated CO2 molecules as reactant are beneficial for efficient photocatalytic CO2 reduction. Ag/BaLa4Ti4O15 and Ag/NaTaO3:Ba reduce CO2 to CO as a main reduction reaction using water as an electron donor even in just water and an aqueous NaHCO3 solution. A Rh-Ru cocatalyst on NaTaO3:Sr gives CH4 with 10% selectivity (Faradaic efficiency) based on the number of reacted electrons in the photocatalytic CO2 reduction accompanied by O2 evolution by water oxidation.Visible-light-responsive photocatalyst systems are indispensable for efficient sunlight utilization. Z-scheme systems using CuGaS2, (CuGa)1-xZn2xS2, CuGa1-xInxS2, and SrTiO3:Rh as CO2-reducing photocatalyst, BiVO4 as O2-evolving photocatalyst, and reduced graphene oxide (RGO) and Co-complex as electron mediator or without an electron mediator are active for CO2 reduction using water as an electron donor under visible light irradiation. These metal sulfide photocatalysts have the potential to take part in Z-scheme systems for artificial photosynthetic CO2 reduction, even though their ability to extract electrons from water is insufficient.A photoelectrochemical system using a photocathode is also attractive for CO2 reduction under visible light irradiation. For example, p-type CuGaS2, (CuGa)1-xZn2xS2, Cu1-xAgxGaS2, and SrTiO3:Rh function as photocathodes for CO2 reduction under visible light irradiation. Moreover, introducing a conducting polymer as a hole transporter and surface modification with Ag and ZnS improve photoelectrochemical performance.

Photocatalytic CO2 Reduction Using Water as an Electron Donor under Visible Light Irradiation by Z-Scheme and Photoelectrochemical Systems over (CuGa)0.5ZnS2 in the Presence of Basic Additives.

We demonstrated photocatalytic CO2 reduction using water as an electron donor under visible light irradiation by a Z-scheme photocatalyst and a photoelectrochemical cell using bare (CuGa)0.5ZnS2 prepared by a flux method as a CO2-reducing photocatalyst. The Z-scheme system employing the bare (CuGa)0.5ZnS2 photocatalyst and RGO-(CoOx/BiVO4) as an O2-evolving photocatalyst produced CO of a CO2 reduction product accompanied by H2 and O2 in a simple suspension system without any additives under visible light irradiation and 1 atm of CO2. When a basic salt (i.e., NaHCO3, NaOH, etc.) was added into the reactant solution (H2O + CO2), the CO formation rate and the CO selectivity increased. The same effect of the basic salt was observed for sacrificial CO2 reduction using SO32- as an electron donor over the bare (CuGa)0.5ZnS2 photocatalyst. The selectivity for the CO formation of the Z-schematic CO2 reduction reached 10-20% in the presence of the basic salt even in an aqueous solution and without loading any cocatalysts on the (CuGa)0.5ZnS2 metal sulfide photocatalyst. It is notable that CO was obtained accompanied by reasonable O2 evolution, indicating that water was an electron donor for the CO2 reduction. Moreover, the present Z-scheme system also showed activity for solar CO2 reduction using water as an electron donor. The bare (CuGa)0.5ZnS2 powder loaded on an FTO glass was also used as a photocathode for CO2 reduction under visible light irradiation. CO and H2 were obtained on the photocathode with 20% and 80% Faradaic efficiencies at 0.1 V vs RHE, respectively.

Highly crystalline Na0.5Bi0.5TiO3 of a photocatalyst valence-band-controlled with Bi(III) for solar water splitting.

Na0.5Bi0.5TiO3 (BG 3.1 eV) with a valence band formed by Bi(iii) was found as a new photocatalyst for solar water splitting. The water splitting activity of highly crystalline Na0.5Bi0.5TiO3 synthesized by a flux method was much higher than that of the samples synthesized by a solid-state reaction. The optimized RhCr2Ox(0.1 mol%)/Na0.5Bi0.5TiO3/CoOOH(0.02 mol%) gave a 5.1% apparent quantum yield at 350 nm and split water even under simulated sunlight irradiation with a 0.05% solar to hydrogen energy conversion efficiency. We have successfully achieved solar water splitting using a one-step photoexcitation type photocatalyst valence-band-controlled with Bi(iii).

In situ photoacoustic analysis of near-infrared absorption of rhodium-doped strontium titanate photocatalyst powder.

Near-infrared absorption of strontium titanate (SrTiO3) doped with rhodium (Rh) was investigated by photoacoustic (PA) Fourier transform infrared spectroscopy. In the absence of an electron acceptor and the presence of a hole scavenger, the largest absorption change in the Rh valence state from tetravalent to trivalent was observed in Rh-doped SrTiO3 prepared at 1473 K, which showed the highest activity for hydrogen evolution. PA measurements revealed the effective redox cycle mechanism between tetravalent and trivalent Rh ions in Rh-doped SrTiO3.

Denaturation of Lysozyme with Visible-light-responsive Photocatalysts of Ground Rhodium-doped and Ground Rhodium-antimony-co-doped Strontium Titanate.

Protein denaturants play an important role in medical and biological research, and development of new denaturants is widely explored to study aging and various diseases. In this research, we treated lysozyme, a model protein, with photocatalysts of ground Rh-doped SrTiO3 (g-STO:Rh) and ground Rh-Sb-co-doped SrTiO3 (g-STO:Rh/Sb) under visible light irradiation to explore the potential of those photocatalysts as denaturants. SDS-PAGE showed that photocatalysis with g-STO:Rh induced the fragmentation of lysozyme into unidentifiable decomposition products. BCA and Bradford protein assays indicated that the peptide bonds and basic, aromatic and N-terminal amino acid residues in lysozyme were denaturated by g-STO:Rh photocatalysis. The denaturation of those amino acids, as quantified by the decreased solubility of lysozyme, was estimated to be more severe by Bradford protein assay than by BCA protein assay. Circular dichroism (CD) spectra of lysozyme revealed that the secondary structure was denatured by g-STO:Rh photocatalysis, indicating that g-STO:Rh photocatalysis is especially effective against the amino acid residues that form the secondary structure via hydrogen bonds. Furthermore, the lytic activity of lysozyme was reduced by g-STO:Rh photocatalysis, owing to denaturation of the enzyme. The visible-light-responsive photocatalyst of g-STO:Rh/Sb accelerates the oxidation reaction and has stronger oxidizing power than g-STO:Rh. Lysozyme was denatured more quickly by g-STO:Rh/Sb photocatalysis than by g-STO:Rh according to analysis by SDS-PAGE, CD spectroscopy, BCA and Bradford protein assays, and lytic activity. These results suggest that higher photocatalytic activity induces more significant denaturation of lysozyme, implying that the main factor of photocatalytic denaturation of lysozyme is oxidation. It should be noted that, as far as we know, this is the first report for denaturation of protein using visible-light-responsive photocatalyst.

α-Helical Peptide-Gold Nanoparticle Hybrids: Synthesis, Characterization, and Catalytic Activity.

BACKGROUND: Gold nanoparticles are promising nanomaterials for catalytic reactions, sensing/imaging systems, photonic/plasmonic devices, and electronics because of their unique physical and chemical properties. To date, significant catalytic activities of gold nanoparticles have been reported for reactions such as carbon monooxide oxidation and 4-nitrophenol reduction, and diverse gold nanoparticle morphologies such as nanospheres, wires, rods, and cubes have been achieved using a variety of capping/stabilizing organic molecules. However, there are few reports on the simultaneous assembly of peptides forming secondary structures and metallic nanoparticles into peptide-metallic particle hybrids under mild aqueous conditions and demonstration of their use as catalysts. Furthermore, the gold nanoribbon surfaces are covered with ß-sheet structures, disrupting the access of substrates to the active sites, thereby possibly inhibiting their catalytic activity. OBJECTIVES: The main objective of this study is design, synthesis, and characterization of peptidegold nanoparticle hybrids that are prepared by an α-helical conformation of a template and examination of the catalytic activities of the hybrids. METHODS: We here report (i) the design, synthesis, and characterization of a new template peptide, RU025, that tends to form an α-helical conformation and self-assembles into network nanoarchitectures in aqueous solution through possibly hydrophobic and electrostatic interactions, (ii) the characterization of gold seed crystals synthesized by mixing RU025 and HAuCl4, (iii) the characterization of peptide-gold nanoparticle hybrids directed by crystal growth with NaBH4 and the dependence on the conditions used for nucleation, and (iv) the catalytic activities of the hybrids towards the reduction of 4-nitrophenol to 4-aminophenol in the presence of excess NaBH4. RESULTS: We demonstrated the design, synthesis, and characterization of a new template peptide, RU025, that tends to form an α-helical conformation and self-assembles into network nanoarchitectures in aqueous solution. Gold seed crystals were synthesized by mixing RU025 and HAuCl4 in a 1:2 molar ratio, followed by further reduction of the gold seed crystals with NaBH4. This reaction afforded worm-like gold nanoparticles embedded in the peptide self-assemblies. The peptide-gold nanoparticle hybrids exhibited catalytic activities for the Langmuir-Hinshelwood type reduction of 4-nitrophenol to 4-aminophenol in the presence of excess NaBH4, with an activation energy of 33 kJ mol-1. CONCLUSION: The size and morphology of gold nanoparticles can be tuned in the nanometer range by altering the peptide concentration relative to HAuCl4 and by changing the nucleation time. This method for constructing peptide-metallic nanoparticle hybrids, in which metallic nanoparticles are dispersed in the peptide self-assemblies, provides highly reactive catalysts.

Efficient photocatalytic degradation of gaseous acetaldehyde over ground Rh-Sb co-doped SrTiO3 under visible light irradiation.

A visible-light-responsive Rh-Sb co-doped SrTiO3 photocatalyst (STO:Rh,Sb) via a solid-state reaction was successfully developed, following pulverization by using ball-milling. The prepared STO:Rh,Sb exhibited a large surface area and showed efficient photocatalytic degradation of acetaldehyde. The photocatalytic activity of STO:Rh,Sb ground for 60 min exceeded that of STO:Rh ground for 60 min (photocatalyst doped without antimony), indicating that doped antimony plays an important role in suppressing the Rh4+, which works as a recombination center, in STO:Rh,Sb. Furthermore, the photocatalytic performance of STO:Rh,Sb ground for 60 min was sustained over 3 cycles, confirming the chemical stability of the photocatalyst. Therefore, ground STO:Rh,Sb has the potential to be applied to environmental remediation under visible light irradiation.

Selective Inactivation of Bacteriophage in the Presence of Bacteria by Use of Ground Rh-Doped SrTiO3 Photocatalyst and Visible Light.

Bacteriophage (denoted as phage) infection in the bacterial fermentation industry is a major problem, leading to the loss of fermented products such as alcohol and lactic acid. Currently, the prevention of phage infection is limited to biological approaches, which are difficult to apply in an industrial setting. Herein, we report an alternative chemical approach using ground Rh-doped SrTiO3 (denoted as g-STO:Rh) as a visible-light-driven photocatalyst. The g-STO:Rh showed selective inactivation of phage without bactericidal activity when irradiated with visible light (λ > 440 nm). After inactivation, the color of g-STO:Rh changed from gray to purple, suggesting that the Rh valence state partially changed from 3+ to 4+ induced by photocatalysis, as confirmed by diffuse reflectance spectroscopy. To study the effect of the Rh4+ ion on phage inactivation under visible-light irradiation, the survival rate of phage for g-STO:Rh was compared to that for ground Rh,Sb-codoped SrTiO3 (denoted as g-STO:Rh,Sb), where the change of Rh valence state from 3+ to 4+ is almost suppressed under visible-light irradiation due to charge compensation by the Sb5+ ion. Only g-STO:Rh effectively inactivated phage, which indicated that Rh4+ ion induced by photocatalysis particularly contributed to phage inactivation under visible-light irradiation. These results suggested that g-STO:Rh has potential as an antiphage material in bacterial fermentation.

Sporicidal performance induced by photocatalytic production of organic peroxide under visible light irradiation.

Bacteria that cause serious food poisoning are known to sporulate under conditions of nutrient and water shortage. The resulting spores have much greater resistance to common sterilization methods, such as heating at 100 °C and exposure to various chemical agents. Because such bacteria cannot be inactivated with typical alcohol disinfectants, peroxyacetic acid (PAA) often is used, but PAA is a harmful agent that can seriously damage human health. Furthermore, concentrated hydrogen peroxide, which is also dangerous, must be used to prepare PAA. Thus, the development of a facile and safe sporicidal disinfectant is strongly required. In this study, we have developed an innovative sporicidal disinfection method that employs the combination of an aqueous ethanol solution, visible light irradiation, and a photocatalyst. We successfully produced a sporicidal disinfectant one hundred times as effective as commercially available PAA, while also resolving the hazards and odor problems associated with PAA. The method presented here can potentially be used as a replacement for the general disinfectants employed in the food and health industries.

Different hollow and spherical TiO2 morphologies have distinct activities for the photocatalytic inactivation of chemical and biological agents.

The inactivation of Escherichia coli and Qß phage was examined following their photocatalytic treatment with TiO2 hollows and spheres that had been prepared by electrospray, hydrothermal treatment, and calcination. The crystal structures of the hollows and spheres were assigned to TiO2 anatase, and the surface areas of the hollows and spheres were determined to be 91 and 79 m(2) g(-1), respectively. Interestingly, TiO2 spheres exhibited higher anti-pathogen performance than TiO2 hollows, a difference we ascribe to the prevention of light multi-scattering by microorganisms covering the surfaces of the TiO2 particles. The photocatalytic decomposition of dimethyl sulfoxide (DMSO) in the presence of TiO2 hollows and spheres was examined in order to study the dependence of photocatalytic activity on TiO2 morphology for the size scale of the reactants. TiO2 hollows provided greater photocatalytic decomposition of DMSO than did TiO2 spheres, in contrast to the pattern seen for pathogen inactivation. Fabrication of photocatalysts will need to vary depending on what substance (e.g., organic compound or biological agent) is being targeted for environmental remediation.