Monolayer Modification of Spherical Amorphous Silica by Clay Nanosheets.

Clay-silica nanocomposite materials (CSiN) were prepared by an electrostatic interaction between negatively charged clay nanosheets and positively charged spherical silica, which was modified with an alkyl ammonium group by silane coupling. By optimization of the preparation conditions, 84% coverage of the silica surface by the clay nanosheets was achieved. Adsorption experiments using cationic porphyrin dyes on the CSiN revealed that the clay nanosheet covers the spherical silica as a single layer and does not detach from the silica surface under aqueous conditions. In addition, it turned out that the cationic porphyrin dye did not penetrate the space between the silica surface and the clay nanosheet. Porphyrin molecules were adsorbed only at the outer surface of the clay nanosheet without molecular aggregation even under the high-density adsorption conditions. By combining spherical silica and clay nanosheets, it is possible to prepare novel hybrid materials where the surface can act as a unique adsorption field for dyes.

Structural Transformation of Azonia[5]helicene Photoproduct via Reaction Field Function of Layered Inorganic Material.

In an attempt to generalize "on surface synthesis", which has unique potential in the area of organic synthesis, the focus was placed on layered silicates having a highly flat surface. The photoreaction of (±)-13-bromo-6a-azonia[5]helicene (AHHBr) and (±)-2-bromo-13-methyl-6a-azonia[5]helicene (AHBrMe) in solution and within the layers was examined. In the case of AHBrMe, the photoproduct was different from that in solution. 1H nuclear magnetic resonance (NMR), Fourier transform-infrared spectroscopy (FT-IR), and electrospray ionization-mass spectrometry (ESI-MS) measurements revealed that the photoproduct obtained within the layers was a benzo-perylene molecule with a completely flat lactone structure (AL). This study is the first example of the successful conversion of a chemical reaction path due to the steric effect of the flat surface of layered silicate.

Effect of remotely connected trialkyl ammonium groups on the dye molecules in the photochemical behavior on the clay nanosheet.

The enhanced emission properties of several cationic dye molecules on the clay surface established as a result of the strong electrostatic interaction and associated molecular flattening leading to either the suppression of non-radiative deactivation processes or the improvement of radiative deactivation processes has been verified, and it is known as surface-fixation induced emission (S-FIE). Here, the differences in the S-FIE properties as well as the self-fluorescence quenching behavior of the dimidium and propidium dyes were compared. Propidium differs from dimidium by the substitution of a propyl (diethyl methylammonium) group at the 5th position instead of the methyl group in dimidium. So, the differences induced by this substitution, which is not even in conjugation with the chromophore part of the dye molecule show a significant impact on the adsorption strength, S-FIE properties, and self-fluorescence quenching behavior. In propidium and dimidium, the suppression of knr was the key factor for emission enhancement on the clay surface. Interestingly, the alkylammonium cation group in the Propidium helped for better adsorption strength as well as to reduce the self-fluorescence quenching behavior on the clay surface as compared to the dimidium. Since the trialkylammonium cation was not in conjugation with the core structure of the molecule and located at a specific distance, it did not interrupt the flattening of the molecule on the clay surface. These results could be beneficial in the construction of efficient photochemical reaction systems, where the molecule having low adsorption strengths can be modified by alkyl ammonium cations, which will not affect molecular planarization.

Fluorescence enhancement of benzimidazolium derivative on clay nanosheets by surface-fixation induced emission (S-FIE).

The photophysical behaviors of benzimidazolium derivative [4-(1,3-dimethylbenzimidazol-3-imu-2-yl)-N, N-diphenylaniline (2-(4-(diphenylamino)phenyl)-1,3-dimethyl-1H-benzo[d]imidazol-3-ium)] (BID) in water, organic solvents and on synthetic saponite were investigated. The fluorescence quantum yield (Φf) of BID was 0.91 on the saponite surface under the optimal condition, while that in water was 0.010. Such fluorescence enhancement on the inorganic surface is called "surface-fixation induced emission (S-FIE)". This fluorescence enhancement ratio for BID is significantly high compared to that of conventional S-FIE active dyes. From the values of Φf and the excited lifetime, the non-radiative deactivation rate constant (knr) and radiative deactivation rate constant (kf) of BID on the saponite surface and in water were determined. Results showed that the factors for fluorescence enhancement were both the increase of kf and the decrease of knr on the saponite surface; especially, knr decreased by more than two orders due to the effect of nanosheets.

Effects of Clay Nanosheets on the Photostability of Cationic Porphyrin.

The photodecomposition behavior of cationic porphyrin ZnTMAP4+ (zinc tetrakis-(N,N,N-trimethylanilinium-4-yl) porphyrin) in water and complexed with clay nanosheets was investigated by light irradiation to the Soret band of ZnTMAP4+. The decomposition of ZnTMAP4+ was observed by UV-visible absorption spectroscopy. While the decomposition quantum yield (ϕdec) was 3.4 × 10-4 in water, that was 9.4 × 10-7 on the exfoliated clay nanosheets. It was revealed that the photostability of ZnTMAP4+ was stabilized by the complex formation with clay. When ZnTMAP4+ was intercalated between the stacked clay nanosheets, ϕdec was further decreased to 4.9 × 10-7. The photostability increased by 361 times and 693 times for the exfoliated and stacked state, respectively. These results indicate that the flat clay surface has the potential to control intra- and intermolecular photochemical reactions.

Association between postoperative hypotension and acute kidney injury after noncardiac surgery: a historical cohort analysis.

PURPOSE: The extent to which postoperative hypotension contributes to renal injury remains unclear, much less what the harm thresholds might be. We therefore tested the primary hypothesis that there is an absolute hypotensive arterial pressure threshold for acute kidney injury during the initial seven days after noncardiac surgery. METHODS: We conducted a single-centre historical cohort analysis of adults who had noncardiac surgery and had creatinine recorded preoperatively and postoperatively. Our exposure was the lowest postoperative mean arterial pressure, defined as the average of the three lowest postoperative pressure measurements. Our primary analysis was the association between the lowest mean arterial pressure and acute kidney injury, defined according to Kidney Disease: Improving Global Outcomes initiative criteria. Our analysis was adjusted for potentially relevant confounding factors including intraoperative hypotension. RESULTS: Among 64,349 patients analyzed, 2,812 (4.4%) patients had postoperative acute kidney injury. Each 5-mm Hg decrease in the lowest mean arterial pressure was associated with a 28% (97.5% confidence interval [CI], 23 to 32; P < 0.001) increase in the odds of acute kidney injury for lowest mean arterial pressures < 80 mm Hg. Higher lowest pressures were not associated with acute kidney injury (odds ratio, 1.08; 97.5% CI, 0.99 to 1.17; P = 0.04) for each 5-mm Hg decrease in the lowest mean arterial pressure. CONCLUSION: Postoperative hypotension, defined as the lowest postoperative mean arterial pressure < 80 mm Hg, was associated with acute kidney injury after noncardiac surgery. A prospective trial will be required to determine whether the observed association is causal and thus amenable to modification.

RéSUMé: OBJECTIF: Nous ne savons pas dans quelle mesure l'hypotension postopératoire contribue aux lésions rénales, et nous connaissons encore moins les seuils de lésion. Nous avons donc testé l'hypothèse primaire selon laquelle il existerait un seuil absolu de tension artérielle hypotensive pour l'insuffisance rénale aiguë au cours des sept premiers jours suivant une chirurgie non cardiaque. MéTHODE: Nous avons mené une analyse de cohorte historique monocentrique auprès d'adultes ayant bénéficié d'une chirurgie non cardiaque et pour lesquel·les les taux de créatinine avant et après l'opération avaient été enregistrés. Notre exposition était la tension artérielle moyenne postopératoire la plus basse, définie comme la moyenne des trois mesures de tension postopératoire les plus basses. Notre analyse principale a porté sur l'association entre la tension artérielle moyenne la plus basse et l'insuffisance rénale aiguë, définies selon les critères de l'initiative KDIGO (Kidney Disease: Improving Global Outcomes). Notre analyse a été ajustée pour tenir compte des facteurs de confusion potentiellement pertinents, notamment de l'hypotension peropératoire. RéSULTATS: Parmi les 64 349 patient·es analysé·es, 2812 (4,4 %) ont présenté une insuffisance rénale aiguë postopératoire. Chaque diminution de 5 mm Hg de la tension artérielle moyenne la plus faible était associée à une augmentation de 28 % (intervalle de confiance [IC] de 97,5 %, 23 à 32; P < 0,001) des risques d'insuffisance rénale aiguë pour les tensions artérielles moyennes les plus faibles < 80 mm Hg. Des tensions les plus faibles plus hautes n'ont pas été associées à une insuffisance rénale aiguë (rapport de cotes, 1,08; IC 97,5 %, 0,99 à 1,17; P = 0,04) pour chaque diminution de 5 mm Hg de la tension artérielle moyenne la plus faible. CONCLUSION: L'hypotension postopératoire, définie comme la tension artérielle moyenne postopératoire < 80 mm Hg la plus basse, a été associée à une insuffisance rénale aiguë après une chirurgie non cardiaque. Une étude prospective sera nécessaire pour déterminer si l'association observée est causale et donc susceptible d'être modifiée.

Intra-operative hypertension and myocardial injury and/or mortality and acute kidney injury after noncardiac surgery: A retrospective cohort analysis.

BACKGROUND: Whether intra-operative hypertension causes postoperative complications remains unclear. OBJECTIVE: We sought to assess whether there is an absolute systolic hypertensive threshold associated with increased odds of a composite of postoperative myocardial injury and mortality, and acute kidney injury. DESIGN: A retrospective cohort analysis using an electronic medical record registry. SETTING: The Cleveland Clinic Main Campus, Cleveland, Ohio, USA, between January 2005 and December 2018. PATIENTS: A total of 76 042 adults who had inpatient noncardiac surgery lasting at least an hour, creatinine recorded preoperatively and postoperatively, and had an available clinic blood pressure within 6 months before surgery. MAIN OUTCOME MEASURES: Univariable smoothing and multivariable logistic regression were used to estimate the probability of each outcome as a function of the highest intra-operative pressure for a cumulative 5, 10, or 30 min. We further assessed whether the relationships between intra-operative hypertension and each outcome depended on baseline systolic blood pressure. RESULTS: The composite of myocardial injury and mortality was observed in 1.9%, and acute kidney injury in 4.5% of patients. After adjustment for confounders, there was little or no relationship between systolic pressure and either outcome over the range from 120 to 200 mmHg. There were also no obvious change points or thresholds above which odds of each outcome increased. And finally, there was no interaction with preoperative clinic blood pressure. CONCLUSIONS: There was no clinically meaningful relationship between intra-operative systolic pressure and the composite of myocardial injury and mortality, or acute kidney injury, over the range from 120 and 200 mmHg.

"In-water" Dehydration Reaction of an Aromatic Diol on an Inorganic Surface.

The effect of a synthetic saponite surface on the "in-water" dehydration reaction of diol was examined using 4-formyl-1-methylquinolinium salt (MQu+) as a substrate. The equilibrium between aldehyde (MQu+-Aldehyde) and diol (MQu+-Diol) was affected by the surrounding environment. The equilibrium behavior was observed by 1H nuclear magnetic resonance (NMR) and UV-vis absorption measurements. Although MQu+ was completely in the form of MQu+-Diol in water, the equilibrium almost shifted to the MQu+-Aldehyde side when MQu+ was adsorbed on the saponite surface in water. In addition, the MQu+-Aldehyde ratio depended on the negative charge density of saponite. The factors that determine MQu+-Aldehyde: MQu+-Diol ratio were discussed from the thermodynamic analysis of the system. These data indicate that the electrostatic interaction between the charged saponite surface and MQu+ stabilized the aldehyde side enthalpically and destabilized it entropically. The major reason for these results is considered to be the difference in adsorption stabilization between MQu+-Aldehyde and MQu+-Diol on saponite surfaces.

Performance of the Hypotension Prediction Index with non-invasive arterial pressure waveforms in non-cardiac surgical patients.

An algorithm derived from machine learning uses the arterial waveform to predict intraoperative hypotension some minutes before episodes, possibly giving clinician's time to intervene and prevent hypotension. Whether the Hypotension Prediction Index works well with noninvasive arterial pressure waveforms remains unknown. We therefore evaluated sensitivity, specificity, and positive predictive value of the Index based on non-invasive arterial waveform estimates. We used continuous hemodynamic data measured from ClearSight (formerly Nexfin) noninvasive finger blood pressure monitors in surgical patients. We re-evaluated data from a trial that included 320 adults ≥ 45 years old designated ASA physical status 3 or 4 who had moderate-to-high-risk non-cardiac surgery with general anesthesia. We calculated sensitivity and specificity for predicting hypotension, defined as mean arterial pressure ≤ 65 mmHg for at least 1 min, and characterized the relationship with receiver operating characteristics curves. We also evaluated the number of hypotensive events at various ranges of the Hypotension Prediction Index. And finally, we calculated the positive predictive value for hypotension episodes when the Prediction Index threshold was 85. The algorithm predicted hypotension 5 min in advance, with a sensitivity of 0.86 [95% confidence interval 0.82, 0.89] and specificity 0.86 [0.82, 0.89]. At 10 min, the sensitivity was 0.83 [0.79, 0.86] and the specificity was 0.83 [0.79, 0.86]. And at 15 min, the sensitivity was 0.75 [0.71, 0.80] and the specificity was 0.75 [0.71, 0.80]. The positive predictive value of the algorithm prediction at an Index threshold of 85 was 0.83 [0.79, 0.87]. A Hypotension Prediction Index of 80-89 provided a median of 6.0 [95% confidence interval 5.3, 6.7] minutes warning before mean arterial pressure decreased to < 65 mmHg. The Hypotension Prediction Index, which was developed and validated with invasive arterial waveforms, predicts intraoperative hypotension reasonably well from non-invasive estimates of the arterial waveform. Hypotension prediction, along with appropriate management, can potentially reduce intraoperative hypotension. Being able to use the non-invasive pressure waveform will widen the range of patients who might benefit.Clinical Trial Number: ClinicalTrials.gov NCT02872896.

Unique Enzyme Activity of Peroxidase on a Clay Nanosheet.

The adsorption behavior and enzyme activity of horseradish peroxidase (HRP) was examined on a synthetic clay nanosheet, whose surface is flat at the atomic level and is negatively charged. The results showed that HRP is adsorbed effectively (adsorption equilibrium constant, K = 1.61 × 107 L mol-1) and that the structure of HRP was altered on the clay surface. The enzyme activity of HRP on the clay surface was evaluated by using H2O2 and tert-BuOOH as a substrate. As a result, HRP on the clay surface was able to work for tert-BuOOH, while HRP in solution did not show any activity. In addition, HRP on SSA showed reactivity even under the high-temperature conditions. These results indicate that the clay nanosheet can be a unique modifier for enzyme activity of HRP.

Hypotension Prediction Index for Prevention of Hypotension during Moderate- to High-risk Noncardiac Surgery.

BACKGROUND: The Hypotension Prediction Index is a commercially available algorithm, based on arterial waveform features, that predicts hypotension defined as mean arterial pressure less than 65 mmHg for at least 1 min. We therefore tested the primary hypothesis that index guidance reduces the duration and severity of hypotension during noncardiac surgery. METHODS: We enrolled adults having moderate- or high-risk noncardiac surgery with invasive arterial pressure monitoring. Participating patients were randomized to hemodynamic management with or without index guidance. Clinicians caring for patients assigned to guidance were alerted when the index exceeded 85 (range, 0 to 100) and a treatment algorithm based on advanced hemodynamic parameters suggested vasopressor administration, fluid administration, inotrope administration, or observation. Primary outcome was the amount of hypotension, defined as time-weighted average mean arterial pressure less than 65 mmHg. Secondary outcomes were time-weighted mean pressures less than 60 and 55 mmHg. RESULTS: Among 214 enrolled patients, guidance was provided for 105 (49%) patients randomly assigned to the index guidance group. The median (first quartile, third quartile) time-weighted average mean arterial pressure less than 65 mmHg was 0.14 (0.03, 0.37) in guided patients versus 0.14 (0.03, 0.39) mmHg in unguided patients: median difference (95% CI) of 0 (-0.03 to 0.04), P = 0.757. Index guidance therefore did not reduce amount of hypotension less than 65 mmHg, nor did it reduce hypotension less than 60 or 55 mmHg. Post hoc, guidance was associated with less hypotension when analysis was restricted to episodes during which clinicians intervened. CONCLUSIONS: In this pilot trial, index guidance did not reduce the amount of intraoperative hypotension. Half of the alerts were not followed by treatment, presumably due to short warning time, complex treatment algorithm, or clinicians ignoring the alert. In the future we plan to use a lower index alert threshold and a simpler treatment algorithm that emphasizes prompt treatment.

Anisotropic energy transfer in a clay-porphyrin layered system with environment-responsiveness.

The adsorption orientation behavior of tetrakis(1-methylpyridinium-3-yl)porphyrin (m-TMPyP) and tetrakis(1-methylpyridinium-4-yl)porphyrin (p-TMPyP) on the clay monolayer prepared by the Langmuir Blodgett (LB) technique was investigated using the absorption and dichroic spectra obtained on a waveguide. It was revealed that the orientation of m-TMPyP and p-TMPyP on the clay monolayer, that is parallel and tilted with respect to the clay surface, depends on the surrounding environments such as water and N,N-dimethylformamide (DMF). The anisotropic photochemical energy transfer between m-TMPyP as a donor and p-TMPyP as an acceptor in the layered system was investigated in water and in DMF-water (9/1 (v/v)) by a fluorescence observation. As a result, while energy transfer efficiency (ηET) was 60% for the parallel-parallel orientation in water, that was 10% for the tilted-tilted orientation in DMF-water (9/1 (v/v)). The major factor for the change of ηET could be a change of the distance between m-TMPyP and p-TMPyP, and the J value that is a parameter for spectral overlap between energy donor's fluorescence and acceptor's absorption.

Which types of clay minerals fix cesium ions effectively? the "cavity-charge matching effect".

How can radioactive Cs+ ions be removed from aqueous solution? From this perspective, the adsorption of Cs+ was investigated by using five types of clay minerals possessing different charge exchange capacities. The fixation ability for Cs+ depended on the charge exchange capacity of the clay minerals. Phlogopite and vermiculite, where the number of charges is almost equal to half the number of siloxane ditrigonal cavities in the structure, exhibited a strong Cs+ fixation ability among these clay minerals. In these clay minerals, effective interlayer collapse, which leads to quasi-irreversible adsorption of Cs+, is expected from the introduction of Cs+ into the layer space. This is named the "cavity-charge matching effect". This study clarifies why only phlogopite and vermiculite can fix Cs+ quite strongly among various types of clay minerals. These findings are beneficial for removing radioactive Cs+ ions from the environment using clay minerals through the cavity-charge matching effect.

Factors for the emission enhancement of dimidium in specific media such as in DNA and on a clay surface.

Dimidium (3,8-diamino-5-methyl-6-phenylphenanthridinium: NH2PhP) is a well-known fluorophore as a DNA probe, although its fluorescence enhancement mechanism is not clear. In this study, we investigated the fluorescence enhancement mechanism of NH2PhP on a clay surface by observing the fluorescence behavior. Four systematically selected phenanthridinium derivatives (PDs): NH2PhP, 3,8-bisdimethylamino-5-methyl-6-phenylphenanthridinium (NMe2PhP), 5-methyl-6-phenylphenanthridinium (PhP) and 5-methylphenanthridinium (P) and synthetic clay were used as guest and host materials, respectively. It was revealed that the suppression of hydrogen bonding with water (N-HOH or NH-OH2) is the dominant factor for the fluorescence enhancement on the clay surface for NH2PhP and NMe2PhP. In addition, judging from the fluorescence enhancement for NH2PhP, NMe2PhP and PhP and no fluorescence enhancement for P on the clay surface, the suppression of rotation of the phenyl ring was indicated to make a partial contribution to the fluorescence enhancement mechanism. Because the fluorescence enhancement behavior was quite similar on the clay surface and in DNA, the obtained results afford an important clue to discuss the fluorescence enhancement mechanism of NH2PhP in DNA.

Optical Humidity Sensing Using Transparent Hybrid Film Composed of Cationic Magnesium Porphyrin and Clay Mineral.

A transparent hybrid film composed of cationic magnesium porphyrin and clay mineral was developed, and its chromic behavior depending on relative humidity (RH) was investigated. The hybrid film was obtained via intercalation of magnesium porphyrin into clay film; magnesium porphyrin was intercalated into the interlayer spaces of the clay mineral without aggregation. The absorption spectra of the hybrid film showed red shifts compared to the aqueous solution of magnesium porphyrin because of the π-conjugated system extension with coplanarization of the meso-substituted pyridinium group and porphyrin ring. The absorption maximum of the hybrid film was gradually shifted to a shorter wavelength, and the color of the hybrid film was changed with increasing RH. The X-ray diffraction measurement suggested that the basal space of clay was expanded with increasing RH, indicating that the interlayer space of clay was expanded by water adsorption, and the spectral shift was induced by the change in coplanarization degree between the porphyrin ring and meso-substituted pyridinium groups.

Photoluminescence by Intercalation of a Fluorescent ß-Diketone Dye into a Layered Silicate.

A ß-diketone dye was packed into the two-dimensional nanospace of a synthetic smectite (Sumecton SA), which is a cation-exchangeable layered silicate, to induce strong emission owing to molecular packing of the dye. An emissive dye, 1-(4-methoxyphenyl)-3-(4-pyridyl)-1,3-propandione, was prepared through a Claisen condensation reaction; the dye exhibited aggregation-induced emission, which is enhanced emission owing to clustering of molecules to form aggregates in poor solvents or in the solid state. The dye was nonemissive in solution. However, strong green emission was observed because of the restriction of molecular motion when the protonated dye was accommodated into the interlayer nanospace of the silicate layers through cation-exchange reactions. The restricted motion was confirmed by the smaller nonradiative relaxation rate constant obtained by time-resolved luminescence and quantum yield measurements. A moderate dye packing (0.11 mmol/g) in the interlayer space is important to obtain enhanced emission, whereas the intercalation of a large amount of dye (0.27 mmol/g) resulted in concentration quenching. Therefore, the interlayer space of the layered silicate used here was responsible for the strong emission because of moderate packing of the accommodated ß-diketones.

Supramolecular Surface Photochemistry: Cascade Energy Transfer between Encapsulated Dyes Aligned on a Clay Nanosheet Surface.

Three coumarin derivatives (7-propoxy coumarin, coumarin-480, and coumarin-540a, 2, 3, and 4, respectively) having different absorption and emission spectra were encapsulated within a water-soluble organic capsule formed by the two positively charged ammonium-functionalized cavitand octaamine (OAm, 1). Guests 2, 3, and 4 absorb in ultraviolet, violet, and blue regions and emit in violet, blue, and green regions, respectively. Energy transfer between the above three coumarin@(OAm)2 complexes assembled on the surface of a saponite clay nanosheet was investigated by steady-state and time-resolved emission techniques. Judging from their emission and excitation spectra, we concluded that the singlet-singlet energy transfer proceeded from 2 to 3, from 2 to 4, and from 3 to 4 when OAm-encapsulated 2, 3, and 4 were aligned on a clay surface as two-component systems. Under such conditions, the energy transfer efficiencies for the paths 2* to 3, 2* to 4, and 3* to 4 were calculated to be 33, 36, and 50% in two-component systems. When all three coumarins were assembled on the surface and 2 was excited, the energy transfer efficiencies for the paths 2* to 3, 2* to 4, and 3* to 4 were estimated to be 32, 34, and 33%. A comparison of energy transfer efficiencies of the two-component and three-component systems revealed that excitation of 2 leads to emission from 4. Successful merging of supramolecular chemistry and surface chemistry by demonstrating novel multi-step energy transfer in a three-component dye encapsulated system on a clay surface opens up newer opportunities for exploring such systems in an artificial light-harvesting phenomenon.

Room temperature phosphorescence from a guest molecule confined in the restrictive space of an organic-inorganic supramolecular assembly.

Stable room-temperature phosphorescence of guest aromatic molecules was achieved by the effective suppression of oxygen quenching. The organic capsule (first wall) suppressed static oxygen quenching by enclosing a guest molecule, and dynamic quenching via the capsule opening-closing process was well suppressed and manipulated by the intercalation of this capsule into the restrictive space between clay nanosheets (second wall).

Sequential energy and electron transfer in a three-component system aligned on a clay nanosheet.

To achieve the goal of energy transfer and subsequent electron transfer across three molecules, a phenomenon often utilized in artificial light harvesting systems, we have assembled a light absorber (that also serves as an energy donor), an energy acceptor (that also serves as an electron donor) and an electron acceptor on the surface of an anionic clay nanosheet. Since neutral organic molecules have no tendency to adsorb onto the anionic surface of clay, a positively charged water-soluble organic capsule was used to hold neutral light absorbers on the above surface. A three-component assembly was prepared by the co-adsorption of a cationic bipyridinium derivative, cationic zinc porphyrin and cationic octaamine encapsulated 2-acetylanthracene on an exfoliated anionic clay surface in water. Energy and electron transfer phenomena were monitored by steady state fluorescence and picosecond time resolved fluorescence decay. The excitation of 2-acetylanthracene in the three-component system resulted in energy transfer from 2-acetylanthracene to zinc porphyrin with 71% efficiency. Very little loss due to electron transfer from 2-acetylanthracene in the cavitand to the bipyridinium derivative was noticed. Energy transfer was followed by electron transfer from the zinc porphyrin to the cationic bipyridinium derivative with 81% efficiency. Analyses of fluorescence decay profiles confirmed the occurrence of energy transfer and subsequent electron transfer. Merging the concepts of supramolecular chemistry and surface chemistry we realized sequential energy and electron transfer between three hydrophobic molecules in water. Exfoliated transparent saponite clay served as a matrix to align the three photoactive molecules at a close distance in aqueous solutions.

[Surgical Resection for Carcinoma Arising from the Remnant Intrapancreatic Bile Duct after Excision of a Congenital Choledochal Cyst - A Case Report].

A 77-year-old woman presented with a high fever. She had a history of resection of the extrahepatic bile duct, cholecystectomy, and hepaticojejunostomy for a congenital choledochal cyst, 23 years previously. Computed tomography showed a tumor measuring 90mm behind the head of the pancreas. This tumor appeared to invade the duodenum and pancreas, although swollen lymph nodes and distant metastasis were not detected. The patient was diagnosed with a carcinoma arising from the intrapancreatic remnant bile duct. A subtotal stomach-preserving pancreaticoduodenectomy and regional lymphadenectomy were performed. The patient remains alive and well with no evidence of disease 11 months after resection.