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Cu ions in waste water can be removed by ferrite treatment, but the reduction of Cu2+ by Fe2+ and the mechanism of Cu+-ferritization are not made clear.In this paper, the authors studied the behavior of Cu2+ and Fe3+ in the ferrite treatment with chemical analysis and X-ray diffraction and the dissolution of Cu from products obtained by the ferrite treatment. Cu2+ was almost reduced to Cu+ before aeration and Cu+ existed as Cu2O. But Cu2O in the suspension was oxidized to CuO after the oxidation of Fe2+, and CuO is easy to dissolve in acidic condition.

Effects of θe, needed for Fe (II) oxidation with air, initial molar ratio Fe2+/M2+ (M : Zn, Cd and Mn) and reaction temperature on ferritization of heavy metal ions were studied by stability of heavy metal, obtained by leaching test of ferrite suspension at pH 3-3.5, and yield of Fe3O4 (3·Fe2+/Total-Fe).θe≥1.5 h, θe is controled by the conditions of aeration and mixing speed, the stability and the yield of Fe3O4 were not effected by θe, but they were increased with Fe2+/M2+ and reaction temperature.Sedimentation of these ferrites was also studied for the separation of sludge from the treated water. Settling velocity of ferrite became faster, when the ratio of spinnel formation is over 0.5-0.6.

A VUV (vacuum-UV) three-photon hot molecule reaction is demonstrated in this study for gaseous triphenylmethane (TPM). A TPM radical was derived from vibrationally hot TPM, which sequentially absorbed the second and third photons within a laser pulse. In the condensed phase, TPM radical was formed by the deprotonation of a cation radical, which was formed by the two-photon ionization. The multiphoton reaction via a hot molecule is a special case which can produce a neutral radical directly. This study also shows that more than two high-energy photons (VUV) can be absorbed and accumulated as vibrational energy. It should be emphasized that an internal conversion is not a useless photophysical process, but a very interesting process for forming an important intermediate in multiphoton laser chemistry.

Chromated copper arsenate, which is used worldwide as a wood preservative, can adversely affect human health. Accumulating evidence suggests that chromium (Cr) and arsenic (As) can potentially disrupt the redox balance and cause respiratory diseases and cancer in humans. The present study was designed to determine the combined toxic effects of these metals in the lungs and to clarify the specific molecules that are stimulated by combined exposure to both metals. Male C57BL/6J mice were intratracheally instilled with arsenate [As(V)], hexavalent chromium [Cr(VI)], or a combination of both metals. Mice were sacrificed 2 days after treatment to collect bronchoalveolar lavage fluid and lung tissue samples. Inflammation, cytotoxicity, apoptosis, and oxidative stress markers were measured. Our results indicated that administration of Cr(VI) alone or in combination with As(V) induced neutrophil-dominant inflammation as well as phosphorylation of mitogen-activated protein kinases; effects of treatment with As(V) alone were comparatively less potent. By analyzing the production of interleukin-6 and activity of lactate dehydrogenase and caspase, we confirmed that co-treatment intensified pulmonary injury and that it was accompanied by oxidative stress, as confirmed by marked increases in the production of reactive oxygen species, reduced glutathione content, and thioredoxin reductase (TRXRD) activity. Expressed mRNA levels of heme oxygenase-1, glutamylcysteine ligase, glutathione peroxidase 2, thioredoxin (TRX) 1, and TRXRD1 were also enhanced by co-treatment, whereas treatment with As(V) alone reduced the mRNA expression level of TRX2. Our data suggest that co-treatment with As(V) exacerbated Cr(VI)-induced pulmonary injury and that this effect may be exerted through a disruption in the balance among several antioxidant genes.

Molecular ions of alkylphenols and cyclohexane were found to be produced more effectively with longer wavelength excitation. The cation resonance would enhance the fragmentation in femtosecond ionization of the organic molecules.

Removal of binder materials used in manufacturing ceramic green body was studied in the environment of supercritical C0 2 with/without some organic entrainers. Lighter organic binder materials (higher alcohols and higher fatty acids) were extracted, but not the heavier organic binder materials. Values of diffusion parameter for the lighter organic materials were determined. When ethanol, methylene chloride, or n -hexane were added as entrainers in SC-CO 2 , the diffusion parameter of the lighter materials became considerably larger compared to the case without the entrainers.

While several skin sensitization tests have been developed and are available as regulatory toxicity tests at present, no such tests for the airway have been established. We have been developing an animal model by introducing an elicitation phase into the mouse IgE test (MIGET) for assessment of agricultural chemicals with airway sensitization potential. In the current study, trimellitic anhydride (TMA), a representative low molecular weight (LMW) airway sensitizer, was examined for its sensitization potential in our mouse model. Mice were epicutaneously sensitized to TMA on Days 0 and 7, followed by an inhalation challenge with TMA dust at high or low concentration on Day 14. Groups of different sensitization route including inhalation were established for comparison of effectiveness of immunization. Non-sensitized animals challenged with TMA dust served as controls. An ovalbumin-sensitized and -challenged animals constituted a reference group (OVA). Enhanced pause (Penh) was measured as an indicator of airflow disturbance by using a restrained flow whole body plethysmograph. The high TMA concentration group exhibited an augmented Penh, elevated IgE values, and pronounced influx of eosinophils into their BAL fluid and minor infiltration of inflammatory cells including eosinophils into the lung. The low TMA concentration group also exhibited elevated IgE values and a less frequent occurrence of minor lung inflammation, but these were not accompanied by any positive responses in Penh and BAL fluid. Almost all mice in the other immunization route groups exhibited negative responses for any parameter examined. The OVA group showed no changes in breathing pattern during the inhalation challenge despite presenting a high total serum IgE value. These results suggest that this mouse model may be useful for assessment of airway sensitization potential of agrochemicals, but by way of epicutaneous sensitization.

Desorption of C 60 + and its dimer cation was investigated on irradiation with nonresonant femtosecond laser pulses at 1.4 μm. Ionization of solid C 60 revealed strikingly different features, such as the absence of multiply charged molecular ions, the emission of C + at low laser intensity, C 2 attachments, delayed ionization, and dimer cation formation, as compared with the gas phase experiments. The large kinetic energy distribution of ions found in this study indicated that the desorption process was mainly driven by an electrostatic mechanism rather than by thermal, photochemical, or volume expansion mechanisms. Singly charged C 60 emission by a Coulomb explosion due to the high density of C 60 + is suggested.

A new scheme for phase control of optical components with laser ablation has been developed. One can ablate the surface shape of optical plastic material coated on a glass plate by using 193-nm laser light to control the transmission wave front. The surface shape is monitored in situ and corrected to attain the desired aberration level. The irradiation fluence is approximately 40 mJ/cm(2), and the ablation depth/pulse is approximately 0.01 microm/pulse for UV-cured resin. A wave-front aberration of 3.0 lambda is reduced to 0.17 lambda for flat surface shaping. For spherical surface generation, an aberration of 2.5 lambda is reduced to 0.2 lambda. The increase in surface roughness is kept within acceptable levels.

Laser photochemistry of lanthanid and actinideions in solution is briefly reviewed. A typical example is the photoreduction of Eu3+ in aqueous solution. A nanosecond laser photolysis techniquewas applied to this reaction. The reduction yield was found to be several percent. Detailed studies on these metal ions will provide new methods for nuclear reprocessing.

セラミックス成形体中に含まれるバインダーの低分子系有機物は超臨界炭酸ガスにより除去できることが分かった.その低分子系有機物の成形体中有効拡散係数は, 圧力19.6MPa, 温度333～353Kの範囲においては温度やその低分子系有機物の含有量に依存し, (2～3.5) ×10-10m2/sであった.超臨界炭酸ガス処理中での成形体中に残留する低分子系有機物の量について実測値と理論計算値との一致は良好であった.

Ionization of organic molecules irradiated with intense infrared femtosecond pulses is explained from the perspective of intact molecular ion formation. Although fragmentation is more suppressed in general by femtosecond pulse excitation than pico- and nanosecond pulse excitations, molecules are still often heavily fragmented. Among the excitation parameters affecting ionization and fragmentation processes, excitation wavelengths and pulse durations at a fixed laser intensity have been found to drastically change ionization patterns. Intact molecular ions are produced when the wavelengths are non-resonant with the electronic levels of cations, whereas fragmentation proceeds to a large extent when the wave length is resonant with the electronic transitions. An ultimately short pulse presumably leads to the formation of fragment-free ions. Time-of-flight spectra of femtosecond pulse ionization of cyclohexadiene isomers, 2,3-dimethyl-1,3-butadiene, naphthalene, anthracene, and dioxin are presented. The great advantage of femtosecond laser mass spectrometry (FLMS) for the intact molecular ion formation is shown by referring briefly to the results obtained for dioxin. Some details of the experimental methods, such as a method of estimating irradiation intensity, are described.

This study aimed to clarify and compare the awareness and perceptions of the specialized inpatient palliative care service. A cross-sectional questionnaire survey was performed on the general population selected by stratified two-stage random sampling (n=2,548) and bereaved families who actually received specialized inpatient palliative care at 12 palliative care units (PCUs) in Japan (n=513). The respondents reported their awareness and perceptions of PCUs. Thirty-eight percent of the general population answered that they had "considerable" or "moderate" knowledge of PCUs, but 24% answered that they had "no" knowledge. Bereaved families who received PCU care (PCU-bereaved families) were likely to have better perceptions of PCUs than the general population: "alleviates pain" (68% of the general population and 87% of PCU-bereaved families agreed), "provides care for families" (67% and 86%, respectively), and "provides compassionate care" (67% and 87%, respectively). Both groups, however, expressed concerns about PCUs: "a place where people only wait to die" (30% and 40%, respectively) and "shortens the patient's life" (8% and 17%, respectively). These perceptions were associated with overall satisfaction with received care, and differed among the 12 PCUs. In conclusion, public awareness of PCUs was insufficient in Japan. Although PCU-bereaved families were generally likely to have better perceptions of PCUs than the general population, both groups shared concerns that a PCU was a place where people only wait to die. To facilitate appropriate use of specialized palliative care services, more efforts to inform the general population about the actual palliative care system are needed. In addition, the role of PCUs might be reconsidered in terms of the continuum of cancer care.

The ring-cleavage reactions of a series of benzocycloalkenes were studied using an ArF excimer laser. Product formation was significantly suppressed in the presence of nitrogen; therefore, the presence of vibrationally excited states (hot molecules), as intermediates, was indicated. The product of highly strained benzocyclobutene was linearly proportional to the laser fluence, whereas those of benzocyclopentene and benzocyclohexene were proportional to the square of the laser fluence in the presence of nitrogen. These phenomena cannot be understood as photochemical bond cleavage in the electronic excited state, but instead appear to be the result of single- and two-photon reactions of hot molecules. The dissociation rate constants were evaluated by a statistical rate theory under the assumption that the reaction occurred from the hot molecule. The reaction rate of highly strained benzocyclobutene was predicted to be faster than the collisional rate with foreign gas, even if it had vibrational energy equivalent to one photon; however, the reaction rates of less strained benzocyclohexene were expected to compete with the collisional rate when the vibrational energy was equivalent to two photons. Benzocyclopentene was an intermediate case and showed both single- and two-photon reactions. The dissociation rate constant of 1.4 x 10(6) s(-1) was successfully obtained from benzocyclopentene under collision-free conditions. This value was in fair agreement with the calculated value. The different dissociation rate constants of the molecules were well-explained in terms of the strain energy. Although the strain energy varies in a wide range (10-130 kJ mol(-1)), the simple model of the calculations reproduced the observed values of the CH2-CH2 bond dissociation in strained benzocycloalkenes.

A two-generation reproductive toxicity study was conducted with 2,4-dichlorophenol (2,4-DCP), an agent suspected of exerting endocrine disrupting effects. Wistar-Hannover rats, 24/sex/group, were given diet containing 2,4-DCP at dose levels of 0, 500, 2000 or 8000 ppm to examine the potential effects of the test substance on parental animals and their offspring over 2 successive generations. Neither clear systemic nor reproductive toxicity of 2,4-DCP was apparent in the 500 ppm group. In the 2000 ppm group, mean body weight gain and food consumption of females were lowered significantly during the treatment period. Effects on body weights and food consumption were more serious in the 8000 ppm group, both males and females being significantly affected. Reproductive effects of the test substance were also observed in the 2000 and 8000 ppm groups dose-dependently. Observations included significantly increased uterine weights of F1 and/or F2 female weanlings and reduced numbers of implantation sites and live births of F1 parental females. These results suggest that 2,4-DCP has weak reproductive toxicity, possibly based on endocrine activity. However, the basic mechanisms for apparent estrogenic effects of 2,4-DCP remain to be elucidated.

The photoreduction mechanism of Sm3+ to Sm2+ was studied using a KrF excimer laser. Reduction occurred via a one-photon process (different from previous suggestions). The reduction yield was 0.34 ± 0.09 in a methanol solution of 18-crown-6 with Sm3+. The oxidized solvent (*CH2OH radical) was observed in the transient spectrum.

Background Communication about the ending of anticancer treatment and transition to palliative care is a difficult task for oncologists. The primary aims of this study were to clarify family-reported degree of emotional distress and the necessity for improvement in communication methods when communicating about the ending of anticancer treatment, and to identify factors contributing to the levels of emotional distress and the necessity for improvement. Methods A multi-center questionnaire survey was conducted on 630 bereaved family members of cancer patents who received specialized palliative care in Japan. A total of 318 responses were analyzed (effective response rate, 62%). Results Thirty-nine percent of the bereaved family members reported that they were ‘very distressed’ in receiving information about the ending of anticancer treatment, and 19% reported ‘considerable’ or ‘much’ improvement was necessary in the communication methods. High-level emotional distress was significantly associated with younger patient age, female family gender, the experience of the physician stating she/he could do nothing for the patient, the physician's unwillingness to explore their feelings, and prognostic disclosure of definite survival periods without probabilities or ranges. High levels of perceived necessity for improvement in the communication methods were significantly associated with the experience of the physician stating she/he could do nothing for the patient, physicians not explaining treatment goals in specific terms, physicians not pacing the explanation with the state of family preparation, physicians not being knowledgeable about the most advanced treatments, and the atmosphere not being relaxing enough to ask questions. Conclusions In receiving the information about ending anticancer treatment, a considerable number of families experienced high levels of emotional distress and felt a need for improvement of the communication methods. The strategies to alleviate family distress could include: (i) assuring that physicians will do their best to achieve specific goals, without saying that they can do nothing for the patient; (ii) providing information, including estimated prognosis, in careful consideration of families' preparation and the uncertainty for each patient; (iii) exploring families' emotions and providing emotional support; (iv) acquiring knowledge about advanced treatments; and (v) making the atmosphere relaxing enough to allow families to ask questions.

Ecotoxicological hazards of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (p, p′-DDT) were investigated by a one-generation reproduction study using Japanese quail (Coturnix coturnix japonica) under an Organization for Economic Co-operation and Development (OECD) draft new test guideline 206 following acute and subchronic toxicity studies. In the subchronic feeding toxicity study, tremors, convulsions, and deaths were observed with a clear sex difference, males being more susceptible than females. The estimated total number of sperm tended to decrease in a dose-dependent manner at the end of 6-week treatment. In the one-generation reproduction study conducted at dose levels of 0, 6, 30, and 150 ppm, the estimated total number of sperm tended to decrease in a dose-dependent manner with a significant difference at 150 ppm. Tremors were observed in the majority of hatchlings in the 150 ppm group and at lower incidences in the 30 ppm group. Significantly high mortality rate in chicks persisted from treatment week 3–6 in the 150 ppm group and at treatment weeks 4 and 5 in the 30 ppm group. Despite of these severe adverse effects of p,p′-DDT on hatchlings and chicks, fertilization, egg laying, eggshell thickness or embryonic development was hardly impaired by p, p′-DDT or its metabolites. From these results, it appears that the OECD draft new avian one-generation reproduction test guideline is effective for ecological hazard assessment of chemicals.

Coulomb explosions of benzene induced by an intense femtosecond laser field were examined in the present study by time-of-flight (TOF) mass spectrometry at laser intensities of 8.0/spl times/10/sup 16/ W cm/sup -2/, with a pulse width of 120 fs. The multiply charged ions of C/sup q+/ (q=1/spl sim/4) and H/sup +/ were detected and their energies were determined to be distributed in the range of 0/spl sim/120 eV. The explosions were concluded to be anisotropic because the kinetic energies of multiply charged carbon ions are high parallel to the laser electric field. Molecular dynamics (MD) simulations, including the effects of tunnel ionization, electron recombination, and the spatial configuration of benzene for laser electric fields were performed to elucidate the kinetic-energy distributions and explosion dynamics. The simulations suggest that the charge-hopping mechanism enhances ionization, finally leading to an anisotropic explosion. Furthermore, we have found that the time profiles of the hopping greatly depend on the spatial configurations in the case of the benzene.

Parent ions of pentachlorobenzene and pentachlorophenol have been detected as a major product in a laser intensity region less than 1/spl times/10/sup 14/ W cm/sup -2/ and that the mechanism is explained in terms of non-resonant multiphoton ionization.

Photoreduction yields of Eu3+ to Eu2+ in aqueous and alcoholic solutions were determined. The highest quantum yields were found to be 0.97 ± 0.16 for EuCl3 in methanol under 308 nm excitation and 0.94 ± 0.17 in 2-propanol under 248 nm excitation. The lowest quantum yield was 0.12 ± 0.02 for Eu(ClO4)3 in aqueous solution under 193 nm excitation. The high photoreduction yields for EuCl3 indicate that Cl' reacts efficiently with neighbouring alcohols. The yield was found to depend on the excitation wavelength for EuCl3 in methanol solution.

Summary form only given. In diatomic molecules, Coulomb explosion has been found to begin at a critical internuclear distance larger than R/sub e/. and in clusters an isotropic explosion with MeV particles have been observed. Benzene can be classified as an intermediate case between two- to three-atom molecules and large clusters' The present results show that the explosion is anisotropic and has no clear critical structure.

C 60 vapor was irradiated with an intense femtosecond laser pulse (1 × 10 16 W/cm 2 in 120 fs at a wavelength of 800 nm). Multiply charged carbon ions, up to C 4+ , were detected in the time-offlight spectra We have measured both energy and angular distributions with respect to the laser polarization direction for ions with different charge number. The kinetic energy of ions are distributed above 1 keV. The angular distribution measurement shows that the highly charged ions of C 3+ and C 4+ are mostly distributed in the direction parallel to the laser polarization, and the C + ions are slightly distributed in the direction perpendicular to it. These observations clearly indicate that an anisotropic explosion takes place. The average energy of ions with the different charge number is found to be proportional to the square ofthe charge number, while the maximum energy is proportional to the charge number. Classical molecular dynamics simulations have been successfully carried out reproducing not only the energy spectra but also the angular distributions of ions. The simulations suggest that the most crucial process forthe anisotoropic Coulomb explosion of C 60 is not the electron impact ionization, but the cascade hopping of electrons.

The five and possibly seven-photon fluorescence was observed for organic molecules in solution for the first time. A high-intensity laser enabled us to measure the properties of the high and any-order processes, and the emission could be directly visualized by the eye. These results showed that the common two-photon microscope could be upgraded to the higher order multiphoton microscope by choosing suitable excitation wavelengths. The multiphoton absorption cross sections differed by a factor of 10(33) as the order of the multiphoton process increased.

A new method for figuring the surface profile of optical plastics for precise optics using short wavelength laser light have been proposed. The surface of the optical plastic coated on the glass substrate is ablated by ArF laser light on the interferometer. The surface profile is measured simultaneously with the ablative figuring. The ablation rate of PMMA is 0.003 μm per pulse at an energy density of 58 mJ/cm2.

EuO (Europium(II) oxide) nanocrystals are prepared under irradiation by means of an ArF excimer laser. The formation of EuO nanocrystals with the clear lattice fringes was confirmed by TEM image. The crystal growth was monitored by the emission spectra.

We have developed a new technique for detecting the concentration of Cl in aqueous solution. The concentration of CF is determined by measuring the absorbance of C12 which is formed by ArF laser irradiation. The absorption maximum of C12 is located at 340 nm. A linear relationship between the absorbance and the concentration on a log-log scale was confirmed. The detection limit of 1x10-5 M has been achieved. This method is applicable to real-time and in-line measurement, and to other halogen ions.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The C-H bond in the methyl group of toluene, p-xylene, and mesitylene dissociates to the corresponding radicals from the hot molecules with internal energy of 8 eV. The dissociation rate constants were measured by the method of nanosecond laser photolysis. These rate constants can be predicted by a statistical theory on the basis of those measured by 193 nm irradiation. The C-C bond in paracyclophane was found to dissociate by two photons at 193 nm.

A 5 kpps copper vapor laser (CVL) switched by semiconductors has been demonstrated for the first time. The solid state power exciter consists of static induction (SI) thyristors and two stage magnetic pulse compression circuits with saturable inductors. The maximum electric efficiency was 67%. The exciter showed the high transfer efficiency in the input energy range of 2.9kW to 6.5kW by optimizing the reset currents for saturable inductors. The average laser power was 21W at a 5kpps repetition rate. An overall system jitter for synchronization was successfully reached down to a very small value of +/- 2.5ns.

Effectively luminescent organic polymers were successfully fabricated by incorporating deuterated hexafluoroacetylacetonato Nd(III) or Eu(III) complex and DMSO-d6 in polyalkylmethacrylate matrices with low percentage of H atoms.

Methane derivatives of CH(3)-X (X: H, F, Cl, Br, I, and CN) were ionized and fragmented by an intense femtosecond laser with a 40 fs pulse at 0.8 microm in intensities of 10(13)-10(15) W cm(-2). The curves of the ionization yields of CH(3)-X versus laser intensities have been found to be fitted with an atomic ionization theory (the theory of Perelomov, Popov, and Terent'ev) that has been established to reproduce experimental results well for rare gas atoms. The saturation intensities have been reproduced within a factor of 1.6 of the calculated ones. For molecules with low ionization potentials such as amines, another atomic ionization theory (the theory of Ammosov, Delone, and Krainov) reproduced the saturation intensities. The atomiclike ionization behavior of molecules indicates that the fragmentation occurs after the ionization. The fragmentation mechanisms after the ionization of some molecular ions are discussed.

The authors investigated Coulomb explosions of ethynylbenzenes under intense femtosecond laser fields. Deuteration on the edge of the triple bond gave information about specific fragment emissions and the contribution of hydrogen migration. Some fragments not resulting from migration were emitted in the direction of laser polarization. These were ethynyl fragment ions (D(+), CD(+), C(2)D(+), and C(3)D(+)). Although two bonds have to be cleaved to produce C(3)D(+), the rigid character of the triple bond was maintained in the Coulomb explosion process. In contrast, fragment ions, which are formed after single or double hydrogen migration, showed isotropic emissions with distinct kinetic energies. The character of the substituents has been found to hold even under strong laser light fields where violent fragmentation took place. The ethynyl parts were emitted like bullets from the molecular frame of ethynylbenzene despite the explosion into pieces of the main body of benzene ring.

The authors compared circularly and linearly polarized lights in the ionization and fragmentation of anthracene, using 800 nm femtosecond laser pulses at intensities of 10(13)-10(15) W cm-2. Singly and doubly charged intact molecular ions as well as numerous fragment ions were observed in the mass spectra, which were investigated as a function of laser intensity and polarization. At comparable intensities above the saturation threshold for complete ionization, the fragmentation pathways are enhanced with a circularly polarized field compared to a linearly polarized field. Resonant excitation of the molecular cation through the 2Au--2Bg transition is proposed to be the initial step to ion fragmentation. The circularly polarized field interacts with a larger fraction of the randomly oriented molecules than the linearly polarized field, and this is considered to be the reason for the enhanced fragmentation brought about by circularly polarized light.

Photosensitized luminescence of Nd3+ in solution was successfully observed for the first time by coordinating the metal cation with deuterated 4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-pentadecafluoro-1-pentafluorophenyl-1,3-decanedione as a ligand with a low vibrational chromophore.

Water was photoionized through a one-photon process upon 193 nm laser irradiation. The quantum yield of photoionization was a few percent. Multiphoton ionization was not observed in this work, up to the laser fluence of 1.6 J/cm2.

Gaseous benzene and benzene‐d6 have been photolyzed with a 158 nm laser. Transient species have been found to have decay rate constants (2.2±0.2)×107 s−1 and (0.7±0.2)×107 s−1, respectively. These rates are explained in terms of the C–H/C–D dissociation by the hot molecule mechanism.

Photo-oxidation of water in a system consisting of perfluorinated p-terphenyl (F-OPP-3) as a photosensitizer, O2 as an oxidative quencher and benzene as a hydroxyl radical scavenger is mechanistically studied by laser flash photolysis and γ-ray and pulse radiolysis. The radical cation of F-OPP-3 (F-OPP-3˙+) is formed via the oxidative quenching of its excited singlet state by O2. The decay of F-OPP-3˙+ observed in transient spectroscopy is enhanced by the addition of water to the system, indicating that F-OPP-3˙+ plays a crucial role in the one-electron oxidation of water.