Ischemic time by the intermittent occlusion of hepatic inflow (Pringle’s maneuver) influences surgical outcome after hepatectomy

Background: Intermittent occlusion of hepatic inflow, so-called Pringle’s maneuver, is a useful technique to control intraoperative bleeding; however, it can lead to ischemia-reperfusion injury. We examined the influence of ischemic time on surgical factors, posthepatectomy liver function and morbidity. Methods: The clinical records of 296 patients who underwent an elective hepatectomy for liver disease between 2004 and 2013 were retrospectively examined. Univariate and multivariate analyses of clinicopathological and surgical factors associated withhepatic-inflow occlusion time were performed. Results: The mean and median times of total hepatic-inflow occlusion were 47±23 minutes (5-173 mL) and 45 minutes, respectively. The occlusion time was significantly correlated with increased indocyanine-green retention rate, total operation time, amount of blood loss or red cell transfusion, postoperative morbidity and hospital stay (each p<0.05). Blood loss upon the use of occlusion tended to be lower than that in its absence (568±602 mL vs. 887±841 mL) (p=0.075). The occlusion time was shorter in limited resection and longer in central bi-segmentectomy or sectionectomy (p<0.05). The occlusion time was significantly correlated with the maximum alanine aminotransferase level (r=0.291, p<0.01). The predictive cut-off value of occlusion time for these correlated parameters ranged between 45 and 46.5 minutes (p<0.05). Hepatic-inflow occlusion was not associated with morbidity in cirrhosis. Conclusion: A longer ischemic time induced increased blood loss or related transfusion, operating time, postoperative liver injury, complication rate and duration of hospital stay

Rational Design of TADF Polymers Using a Donor–Acceptor Monomer with Enhanced TADF Efficiency Induced by the Energy Alignment of Charge Transfer and Local Triplet Excited States

The photophysics of thermally activated delayed fluorescence (TADF) in phenothiazine-dibenzothiophene-S,S-dioxide (PTZ-DBTO2) molecule is investigated in detail. First, it is shown that the proximity of local triplet excited states (3LE), e.g., 3D or 3A, above or below the DA charge transfer states (CT) is crucial for the efficiency of the TADF mechanism in PTZ-DBTO2. This TADF emitter is then used as a monomer unit to design polymer materials with efficient TADF. The reverse intersystem crossing mechanism (RISC) that supports TADF is able to compete with internal conversion and triplet–triplet annihilation (TTA) in the polymer chains and generates efficient TADF emission in the polymer pristine films. Prototype devices with PTZ-DBTO2 dispersed in 4,4′-bis(N-carbazolyl)-2,2′-biphenyl (CBP) host give excellent performance with EQE of ≈22% at low luminance (<100 cd m−2), for 100 cd m−2 the EQE is 19.4%. In the case of solution processed devices, using the novel TADF polymers, the performance is much lower, EQE ≈3.5% at 100 cd m−2, which is still the highest value for a polymer TADF system at useful brightness, yet reported. This results from a combination of weak charge transport properties in these materials and device fabrication methods that require further improvement. Nevertheless, these results pave the way to explore TADF in polymer light emitting diodes (PLEDs), using less costly deposition methods, such as spin-coating and inkjet printing, which are more appropriate for large area deposition

Relationship between serum ghrelin level and physiology in patients who underwent hepatectomy and pancreatectomy

Aim: Ghrelin is a peptide that is secreted from the stomach and plays a role in appetite, weight gain, and skeletal muscle composition.In the present clinical study, we examined the relationship between ghrelin level and physiology in patients who had undergone major liver and pancreas surgery. Methods: Serum ghrelin level was measured before and after hepatectomy and pancreatectomy. The relationships between nutritional status and postoperative alterations of parameters including the ghrelin level were examined. Results: In 32 patients, the preoperative plasm acyl- (AG) or des-acyl-ghrelin (DAG) and AG/DAG ratio were not significantly different based on gender, type of operation, age and each disease. AG tended to be correlated with the respiration quotient but this was not statistically significant (p=0.08). AG was significantly negatively correlated with hemoglobin and albumin levels. The postoperative plasma ghrelin level was significantly decreased at day 1 in comparison with preoperative levels (p<0.05) and recovered to preoperative levels at day 3. There were no significant differences between hepatectomy and pancreatectomy groups, with no changes of postoperative metabolic parameters. Conclusions: Although serum ghrelin level was transiently decreased, this level was immediately recovered and not influencedby the surgical procedures or its invasiveness

Dibenzo[a,j]phenazine-Cored Donor-Acceptor-Donor Compounds as Green-to-Red/NIR Thermally Activated Delayed Fluorescence Organic Light Emitters

A new family of thermally activated delayed fluorescence (TADF) emitters based on U-shaped D-A-D architecture with a novel accepting unit has been developed. All investigated compounds have small singlet-triplet energy splitting (E-ST) ranging from 0.02 to 0.20eV and showed efficient TADF properties. The lowest triplet state of the acceptor unit plays the key role in the TADF mechanism. OLEDs fabricated with these TADF emitters achieved excellent efficiencies up to 16% external quantum efficiency (EQE)

Effects of photodynamic therapy using talaporfin sodium (Laserphyrin® ) on wound healing in an animal model

Background: Photodynamic therapy (PDT) is an effective laser treatment for locally advanced carcinoma and is promising as neoadjuvant chemotherapy before surgery. The aim of this study was to clarify the adverse effects of PDT using a photosensitizer, talaporfin sodium (Laserphyrin®), for wound healing.Methodology: For PDT, a laser light with a wavelength of 660 nm and a frequency of 10 Hz with a total energy fluency of60 J/cm2 was used. Macroscopic and histological findings of wound healing after PDT were examined in vivo (4-week-old male BALB/c mice).Results: In Model 1, in which skin was cut at 0, 3, 7 days after PDT (n=3, each), wounds were similarly healed 7 days after cutting in all groups, and regenerating epithelium and the number of fibroblasts on histological findings were not different. In Model 2, in which skin defects were created before or after PDT, the size of the defects was larger at day 7 in the groups with skin defects before or after PDT in comparison with groups with no PDT.However, macroscopic wound healing at day 14 was complete in all groups and there were no significant differences among the groups by this point. Histological findings of skin defects at day 14 showed no significant difference in terms of regenerating epithelium and number of fibroblasts in each group with or without PDT.Conclusions: PDT did not influence wound healing and can be safely applied before surgical therapy

Pancreatic Duct-to-mucosa versus Invagination or Complete External Drainage Anastomosis in Case of Small Pancreatic Duct after Pancreaticoduodenectomy: Comparative Historical Review

After pancreaticoduodenectomy (PD), pancreatic duct-to-mucosa anastomosis (PDM) has been usually applied which may prevent risk of pancreatic fistula (PF). In cases with a small pancreatic duct, however, PDM is difficult to complete. Procedures involving the invagination (IV) or complete external tube drainage (CED) are supposed to be alternative options for anastomosis. We retrospectively compared clinical results between PDM and IV or CED in 104 patients with a tiny pancreatic duct who underwent PD. The 77 patients undergoing PDM (the control group) and 27 patients undergoing other procedures, including 19 for CED and 8 for IV, were comparatively examined. Fatty pancreas was commonly observed in CED group. Pancreaticojejunostomy was significantly more frequently applied in CED group, and the operating time in the IV group was significantly longer than in control group (p<0.05). The anastomotic time in CED group tended to be shorter than those in control and IV groups (18 versus 29 and 37 min). The incidences of PF were not significantly different among groups (31% in control, 47% inCED and 14% in IV, respectively); however, a grade B or C level of PF was not observed in the IV group. PDM is often difficult to achieve and inadequate suturing may injure the pancreatic parenchyma in cases of very small pancreatic duct. Re-evaluation of the CED or IV procedure as an alternative option was suggested to be warranted

Benzene substituted with bipyridine and terpyridine as electron-transporting materials for organic light-emitting devices

New electron-transporting materials for organic light-emitting devices (OLEDs) based on trisubstituted benzene with both bipyridine and terpyridine, 1,3-bisbipyridyl-5-terpyridylbenzene (BBTB) and 1-bipyridyl-3,5-bisterpyridylbenzene (BTBB), were developed. Glass transition temperatures of BBTB and BTBB were 93 degrees C and 108 degrees C, respectively, and BTBB was completely amorphous with no melting point. Electron mobilities of BTBB exceeded the order of 10(-4) cm(2) V-1 s(-1), while those of BBTB were very high and reached 10(-3) cm(2) V-1 s(-1) at an electric field of approximately 500 kV cm(-2). These high mobilities contributed to a low voltage operation. For example, in the case of the conventional aluminum trisquinolinol (Alq)-based fluorescent OLED with BTBB, current densities of 3.5 mA cm(-2) and 100 mA cm(-2) were reached at voltages of 3.0 V and 4.5 V, respectively. In addition, ionization potentials of BBTB (6.33 eV) and BTBB (6.50 eV) were sufficiently large to confine holes in common emissive layers.ArticleJOURNAL OF MATERIALS CHEMISTRY. 22(14):6765-6773 (2012)journal articl

Charge-tunnelling and self-trapping: common origins for blinking, grey-state emission and photoluminescence enhancement in semiconductor quantum dots

Understanding instabilities in the photoluminescence (PL) from light emitting materials is crucial to optimizing their performance for different applications. Semiconductor quantum dots (QDs) offer bright, size tunable emission, properties that are now being exploited in a broad range of developing technologies from displays and solar cells to biomaging and optical storage. However, instabilities such as photoluminescence intermittency, enhancement and bleaching of emission in these materials can be detrimental to their utility. Here, we report dielectric dependent blinking, intensity-“spikes” and low-level, “grey”-state emission, as well as PL enhancement in ZnS capped CdSe QDs; observations that we found consistent with a charge-tunnelling and self-trapping (CTST) description of exciton-dynamics on the QD–host system. In particular, modulation of PL in grey-states and PL enhancement are found to have a common origin in the equilibrium between exciton charge carrier core and surface-states within the CTST framework. Parameterized in terms of size and electrostatic properties of the QD and its nanoenvironment, the CTST offers predictive insight into exciton-dynamics in these nanomaterials

Room temperature triplet state spectroscopy of organic semiconductors

Organic light-emitting devices and solar cells are devices that create, manipulate, and convert excited states in organic semiconductors. It is crucial to characterize these excited states, or excitons, to optimize device performance in applications like displays and solar energy harvesting. This is complicated if the excited state is a triplet because the electronic transition is ‘dark’ with a vanishing oscillator strength. As a consequence, triplet state spectroscopy must usually be performed at cryogenic temperatures to reduce competition from non-radiative rates. Here, we control non-radiative rates by engineering a solid-state host matrix containing the target molecule, allowing the observation of phosphorescence at room temperature and alleviating constraints of cryogenic experiments. We test these techniques on a wide range of materials with functionalities spanning multi-exciton generation (singlet exciton fission), organic light emitting device host materials, and thermally activated delayed fluorescence type emitters. Control of non-radiative modes in the matrix surrounding a target molecule may also have broader applications in light-emitting and photovoltaic devices.United States. Dept. of Energy. Center for Excitonics (Award DE-SC0001088