Adsorptive removal of phenol from aqueous solution with zeolitic imidazolate framework-67.

ZIF-67(zinc-methylimidazolate framework-67), one of the zeolitic imidazolate frameworks (ZIFs), was used for the removal of phenol from aqueous solutions via adsorption and shows high adsorption capacity for phenol. The thermodynamic and kinetic adsorption behavior of ZIF-67 for phenol in water with concentration ranging from 50 to 300 ppm were investigated in a batch reactor and a ZIF-67 packed column, respectively. The effects of pH, contact time, zeta potential of the adsorbent and temperature on the adsorption behavior were evaluated, and the results demonstrated that the adsorption is primarily brought about by a specific favorable interaction (electrostatic interaction) between phenol and ZIF-67 surface. The suitability of the Langmuir adsorption model to the equilibrium data was investigated for each phenol-adsorbent system, which the results showed that the equilibrium data for all the phenol-sorbent systems fitted the Langmuir model. Thermodynamic parameters such as Gibbs free energy are calculated from the experimental data at different temperatures. The adsorbent could be perfectly regenerated at 120 °C with little loss in the adsorption ability.

Star1 gene mutation reveals the essentiality of 11-ketotestosterone and glucocorticoids for male fertility in Nile Tilapia (Oreochromis niloticus).

Steroidogenic acute regulatory protein (Star) plays an essential role in the biosynthesis of corticosteroids and sex steroids by mediating the transport of cholesterol from the outer to the inner membrane of mitochondria. Two duplicated Star genes, namely star1 and star2, have been identified in non-mammalian vertebrates. To investigate the roles of star genes in fish steriodogenesis, we generated two mutation lines of star1-/- and star1-/-/star2-/- in Nile tilapia (Oreochromis niloticus). Previous studies revealed that deficiency of star2 gene caused delayed spermatogenesis, sperm apoptosis and sterility in male tilapia. Our present data revealed that mutation of star genes impaired male fertility. Disordered seminiferous lobules and spermatic duct obstruction were found in the testis of both types of mutants. Moreover, significant decline in semen volume, sperm abnormality and impaired fertility were also detected in star1-/- and star1-/-/star2-/- males. In star1-/- male fish, lipid accumulation, up-regulation of steroidogenic enzymes, and significant decline of androgens were found. Additionally, hyperplasic interrenal cells, elevated steroidogenic gene expression level and decline of serum glucocorticoids were detected in star1 mutants. Intriguingly, either 11-KT or cortisol supplementation successfully rescued the impaired fertility of the star1-/- mutants. Taken together, these results further indicate that Star1 might play critical roles in the production of both 11-KT and glucocorticoids, which are indispensable for the maintenance of male fertility in fish.

Cyp17a2 is involved in testicular development and fertility in male Nile tilapia, Oreochromis niloticus.

Background: Steroid hormones play an essential role in many reproductive processes of vertebrates. Previous studies revealed that teleost-specific Cyp17a2 (cytochrome P450 family 17 subfamily a 2) might be required for the production of cortisol in the head-kidney and 17α,20ß-dihydroxy-4-pregnen-3-one (DHP) in ovary during oocyte maturation. However, the role of Cyp17a2 in male reproduction remains to be largely unknown. The aim of this study was to explore the essentiality of cyp17a2 gene in male steroidogenesis, spermatogenesis, and male fertility. Methods: A homozygous mutation line of cyp17a2 gene was constructed in tilapia by CRISPR/Cas9 gene editing technology. The expression level of germ cell and meiosis-related genes and steroidogenic enzymes were detected by qRT-PCR, IHC, and Western blotting. EIA and LC-MS/MS assays were used to measure the steroid production levels. And sperm quality was examined by Sperm Quality Analyzer software. Results: In this study, cyp17a2 gene mutation resulted in the significant decline of serum DHP and cortisol levels. On the contrary, significant increases in intermediate products of cortisol and DHP were found in cyp17a2-/- male fish. The deficiency of cyp17a2 led to the arrest of meiotic initiation in male fish revealing as the reduction of the expression of germ cell-related genes (vasa, piwil, oct4) and meiosis-related genes (spo11 and sycp3) by 90 dah. Afterwards, spermatogenesis was gradually recovered with the development of testis in cyp17a2-/- males, but it showed a lower sperm motility and reduced fertility compared to cyp17a2+/+ XY fish. Deletion of cyp17a2 led to the abnormal upregulation of steroidogenic enzymes for cortisol production in the head-kidney. Moreover, unaltered serum androgens and estrogens, as well as unchanged related steroidogenic enzymes were found in the testis of cyp17a2-/- male fish. Conclusion: This study proved that, for the fist time, Cyp17a2 is indispensable for cortisol and DHP production, and cyp17a2 deficiency associated curtailed meiotic initiation and subfertility suggesting the essentiality of DHP and cortisol in the male fertility of fish.

Acupuncture for Post-Stroke Cognitive Impairment: An Overview of Systematic Reviews.

Background: Post-stroke cognitive impairment (PSCI) is one of the most common complications after stroke. In recent years, as a complementary alternative therapy, many systematic reviews (SRs) and meta-analysis (MAs) have reported the efficacy and safety of acupuncture in improving cognitive function in patients with PSCI, but the quality of evidence is unknown and therefore needs to be evaluated comprehensively. Aim: We aimed to evaluate the SRs of acupuncture for patients with PSCI, to summarize the evidence quality of SRs to provide scientific evidence. Methods: We searched for relevant SRs and MAs in seven databases up to March 22, 2022. Two reviewers independently completed literature retrieval, screening, and data extraction. We used A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR 2) to evaluate the methodological quality; the Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool to determine the strength of evidence; and the ROBIS tool to assess RoB. Results: We identified 14 SRs. The methodological quality of all SRs was low (2/14) or very low (12/14). GRADE results showed 13 were moderate quality (26%), 5 were low quality (10%), and 32 were very-low quality (64%). RoB showed that one SR had a low risk and 13 had a high risk. Moderate quality results showed that combined acupuncture therapy was superior to western medicine or cognitive rehabilitation training in improving cognitive function, the total response rate, and the daily living ability of patients with PSCI. Conclusion: Based on the evidence, acupuncture appears to be effective and safe in improving cognitive function for patients with PSCI, but the overall quality of SRs is not high. High-quality randomized controlled trials are needed to confirm the effectiveness and safety of acupuncture on the cognitive function of patients with PSCI. Systematic Review Registration: PROSPERO CRD42022315441.

Chinese herbal medicine xuebijing injection for acute pancreatitis: An overview of systematic reviews.

Background: At present, a number of systematic reviews (SRs) on Xuebijing injection (a patent in China) in the treatment of acute pancreatitis (AP) or severe acute pancreatitis (SAP) have been published. However, the quality of evidence is uneven and has not been comprehensively evaluated. Aim: We evaluated the efficacy of Xuebijing injection for AP/SAP through an overview of SR, and to provide a scientific basis for its effectiveness and safety. Methods: We searched Cochrane Library, Embase, PubMed, SinoMed, CNKI, Wanfang, and VIP comprehensively. The retrieval period from inception to 30 November 2021, and the two reviewers independently complete the literature retrieval, data extraction and evaluation. The Assessing the Methodological Quality of Systematic Reviews 2 (AMSTAR-2) and the Preferred Reporting Item for Systematic Review and Meta-analysis (PRISMA) were used to evaluate the methodological quality and reporting quality of the SRs, respectively. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) tool was used to evaluate the quality grading of outcomes and the risk of bias in SRs was evaluated by ROBIS Tool. Finally, the RCTs involved in SRs were synthesized. Stata15.1 was used for quantitative analysis of total effectiveness rate, time until relief of abdominal pain, time until relief of abdominal distension, and serum amylase level. Results: Nine eligible SRs were included, including 92 RCTs and 6,837 participants. The quality of SRs was relatively good, and the manuscript structures were relatively complete. However, the methodological quality of SRs was low or critically low. RoB rated 5 SRs as low risk of bias and 4 SRs as high risk of bias. In GRADE, a total of 47 results were included in the 9 SRs, of which 5 results (10.64%) were moderate quality, 22 results (46.81%) were low quality, and 20 results (42.55%) were very low quality. The results of data synthesis showed that Xuebijing injection combined treatment increased the total effectiveness rate of AP patients (RR = 1.19, 95% CI 1.17-1.23, p < 0.0001), and there was no heterogeneity between studies (I2 = 0.0%, p = 0.589). Compared with the control group, Xuebijing injection group shortened the abdominal pain and distension relief time in AP patients (WMD = -1.69, 95% CI -1.88--1.50, p < 0.0001; WMD = -1.48, 95% CI -1.74--1.23, p < 0.0001), with high heterogeneity (I2 = 84.3%, p = 0.000; I2 = 72.2%, p = 0.000). Serum amylase level was also reduced (WMD = -2.06, 95% CI -2.47--1.64, p < 0.0001), with significant heterogeneity (I2 = 71.6%, p = 0.000). A total of one SR reported adverse drug reaction (ADR), no ADRs were observed in the control group. Conclusion: Although the quality of the evidence is not high, it can still reflect the clinical value of Xuebijing injection as an analgesic and anti-inflammatory traditional Chinese medicine in the treatment of AP/SAP. Therefore, future clinical studies should focus on the long-term efficacy and adverse reactions of drugs. Systematic Review Registration: (website), identifier (registration number).

Tunable bandwidth of band-stop filter by metamaterial cell coupling in optical frequency.

In this paper we present a simulation study of nanostructures with unit cells of periodic coupled cut-wire pairs for band-stop properties in the optical frequency range. A band-stop filter with a broader stop band for space transmission is realized by making use of plasmon hybridization. The bandwidth of the filter is tunable over a large range from 56.6 to 182.2 THz by magnetic and electric couplings between adjacent unit cells. An equivalent RLC resonant circuit is proposed to analyze the origin of the coupling effects. The bandwidth tunability by the coupling effect provides good guidance for a metamaterial design that works in broadband frequencies.

Alloy nanoparticle plasmon resonance for enhancing broadband antireflection of laser-textured silicon surfaces.

In this paper, Ag-Au alloy nanoparticles (NPs) were fabricated by dewetting process to enhance the broadband antireflection performance of textured silicon surfaces. The alloy NPs presented a large range of shapes and sizes, which provided an average reflectance (AR) below 4% over the spectral range of 300~1200 nm, a decrease of ~50% and ~90% as compared to the corresponding monometallic NPs and the original flat Si surfaces, respectively. The superior broadband antireflection demonstrated by the alloy NPs are attributed to the enhanced light trapping by alloy nanoparticle plasmon resonance.

Cyp17a1 is Required for Female Sex Determination and Male Fertility by Regulating Sex Steroid Biosynthesis in Fish.

In teleost fish, sex steroids are involved in sex determination, sex differentiation, and fertility. Cyp17a1 (Cytochrome P450 family 17 subfamily A member 1) is thought to play essential roles in fish steroidogenesis. Therefore, to further understand its roles in steroidogenesis, sex determination, and fertility in fish, we constructed a cyp17a1 gene mutant in Nile tilapia (Oreochromis niloticus). In XX fish, mutation of the cyp17a1 gene led to a female-to-male sex reversal with a significant decline in 17ß-estradiol (E2) and testosterone (T) production, and ectopic expression of male-biased markers (Dmrt1 and Gsdf) in gonads from the critical window of sex determination. Sex reversal was successfully rescued via T or E2 administration, and ovarian characteristics were maintained after termination of E2 supplementation in the absence of endogenous estrogen production in cyp17a1-/- XX fish. Likewise, deficiencies in T and 11-ketotestosterone (11-KT) production in both cyp17a1-/- XX sex-reversed males and cyp17a1-/- XY mutants resulted in meiotic initiation delays, vas deferens obstruction and sterility due to excessive apoptosis and abnormal mitochondrial morphology. However, 11-KT treatment successfully rescued the dysspermia to produce normal sperm in cyp17a1-/- male fish. Significant increases in gonadotropic hormone (gth) and gth receptors in cyp17a1-/- mutants may excessively upregulate steroidogenic gene expression in Leydig cells through a feedback loop. Taken together, our findings demonstrate that Cyp17a1 is indispensable for E2 production, which is fundamental for female sex determination and differentiation in XX tilapia. Additionally, Cyp17a1 is essential for T and 11-KT production, which further promotes spermatogenesis and fertility in XY males.

Acupuncture for Relieving Abdominal Pain and Distension in Acute Pancreatitis: A Systematic Review and Meta-Analysis.

Background: Clinical evidence suggests that acupuncture is effective for relieving abdominal pain and distension in acute pancreatitis (AP). However, there is a lack of systematic reviews and meta-analyses that provide high-quality evidence of the efficacy and safety of acupuncture in this context. Aim: To assess the efficacy and safety of acupuncture for relieving abdominal pain and distension in AP. Methods: We searched the PubMed, Web of Science, Embase, Cochrane Library, CNKI, Wanfang, VIP, and China Biomedical Literature databases. Randomized controlled trials of acupuncture plus routine treatment (RT) vs. RT alone or RT plus sham/placebo acupuncture were included. Primary outcomes included total effectiveness rate, VAS scores for abdominal pain and distension, and time until relief of abdominal pain and distension. Secondary outcomes included time until recovery of bowel sound, time until first defecation, length of hospital stay, and APACHE II score. Results: Nineteen eligible original studies (n = 1,503) were included. The results showed that acupuncture in combination with RT had a significant advantage in terms of increasing the total effectiveness rate [risk ratio: 1.15; 95% confidence interval (CI): 1.06-1.24; P = 0.001]. Acupuncture also reduced the VAS score for abdominal pain [weighted mean difference (WMD): -1.45; 95% CI: -1.71 to -1.19; P < 0.0001] and the VAS score for abdominal distension (WMD: -0.71; 95% CI: -1.04 to -0.37; P < 0.0001) in patients with AP. Other results also showed the efficacy of acupuncture. One study reported adverse events after acupuncture. Conclusion: Acupuncture in combination with RT has a better effect than RT alone for relieving abdominal pain and distension in AP. More rigorous studies are needed to confirm this result. Systematic Review Registration: PROSPERO CRD42019147503 (https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=147503).

Acupuncture for heart failure: a Bayesian network systematic review and meta-analysis protocol.

BACKGROUND: Heart failure (HF) is the final stage of cardiovascular disease development, and clinical studies on acupuncture for the treatment of HF are increasing. However, the efficacy and safety of these acupuncture methods are unclear. The purpose of this study is to conduct a meta-analysis of the relevant randomized controlled trials (RCTs) to explain their efficacy and safety through high-quality evidence. METHODS: The databases of the Cochrane Library, PubMed, Web of Science, SinoMed, China National Knowledge Infrastructure (CNKI), Wan-fang, and VIP will be searched from inception date to June 2021. The search will not be restricted by language. This study will include RCTs of various acupuncture methods for HF. Study selection, data extraction, and research quality assessments will be conducted independently by two researchers. The primary outcome is the efficacy rate and heart function, the secondary outcomes are quality of life scores, rehospitalization, and adverse reactions/events. The software RevMan 5.3 and Aggregate Data Drug Information System (ADDIS) will be used for network meta-analysis (NMA). Risk of bias, meta-regression, subgroup analysis, and sensitivity analysis will be performed, and the quality of evidence will be assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework. DISCUSSION: This study will confirm the efficacy and safety of acupuncture in improving the clinical symptoms and heart function of HF, or elucidate which method of acupuncture is better suited to this purpose.

Rln3a is a prerequisite for spermatogenesis and fertility in male fish.

The essential roles of Relaxin3 (RLN3) in energy homeostasis had been well investigated, while the mechanisms of RLN3 regulating reproduction remain to be elusive in mammals. Although two rln3 paralogues have been characterized in several teleosts, their functions still remain largely unknown. In this study, two paralogous rln3 genes, represented as rln3a and rln3b, were identified from the testis of Nile tilapia (Oreochromis niloticus). Rln3a was dominantly expressed in testis, while the most abundant rln3b expression was in brain. In situ hybridization demonstrated that rln3a is abundantly expressed in the Leydig cells of the testis. To understand the role of Rln3 in the testicular development, homologous null-rln3a gene mutant line was constructed by CRISPR/Cas9 technology. Morphological observation demonstrated that null mutation of rln3a gene caused testicular hypertrophy and a significant increase of GSI. However, a significant decrease of spermatogenic cells at different phases, i.e. spermatogonia, spermatocytes, spermatids and sperms was found. Silencing of rln3a gene repressed the expression of key genes in germ cell and Leydig cell. Deficiency of Rln3a led to the significant decrease of 11-KT production, which stimulated the up-regulation of both FSH and LH production in the pituitary via a negative feedback manner possibly. Mutation of rln3a in XY fish led to the hypogonadism with sperm deformation, significant decrease of fertility, and sperm motility, revealing as the high mortality of the offspring obtained by crossing the wild type female and rln3a-/- XY fish. Interestingly, recombinant human RLN3 injection significantly enhanced the sperm motility in rln3a-/- XY fish. Moreover, hCG treatment stimulated the expression of steroidogenic enzyme genes and 11-KT production, which were repressed by rln3a mutation in XY fish. Taken together, this study, for the first time by using a gene knockout model, proved that Rln3a is an indispensable mediator for androgen production in testis via HPG axis, and plays an essential role in spermatogenesis, sperm motility and male fertility in fish.

Rapid glucose detection by surface enhanced Raman scattering spectroscopy.

An approach to reject stray light and improve glucose adsorption was presented. With a self-assembled monolayer (SAM) and a confocal optical configuration applied in this approach, the adsorption and signal to noise ratio (SNR) have been improved respectively. Our experimental results demonstrated that the surface enhanced Raman scattering (SERS) spectroscopy with 9 feature peaks for 100 mM aqueous glucose is successfully obtained in a dry environment in response time as fast as 40 s only. This approach could improve glucose detection in response time and sensitivity effectively in atmosphere environment.

5-Hydroxytryptamine and Dopamine Neurons in the Cerebellum of the New-Hatching Yangtze Alligator Alligator sinensis.

Nissl and immunohistochemical staining methods were used to morphologically characterize the cerebellum of the new-hatching Yangtze alligator, and the cerebellar histological structure and the distribution profiles of 5-hydroxytryptamine (5-HT) and dopamine (DA) neurons were investigated for the first time. The results of cerebellar histological structure showed that there was a ventriculus cerebelli in the cerebellum of the new-hatching Yangtze alligator, the surface of the cerebellar cortex was not very smooth, the cerebellar cortex could be divided into four layers, which include external granular layer, molecular layer, Purkinje cell layer and granular layer, Purkinje cell layer could be characterized specially by multilayer, two cerebellar nuclei termed as the nucleus cerebelli lateralis and the nucleus cerebelli medialis were found in the cerebellar medulla. 5-hydroxytryptamine-immunoreactive (5-HT-IR) and dopamine-immunoreactive (DA-IR) neurons and fibers distributed widely in the cerebellum. The structures and profiles of 5-HT-IR and DA-IR neurons and fibers in the cerebellum of the Yangtze alligator were similar to that reported in other reptiles, but also had some specific features. The abundance of 5-HT and DA in cerebellum suggested that these highly conserved neurotransmitters would play important roles in motor control. Anat Rec, 302:861-868, 2019. © 2018 Wiley Periodicals, Inc.

Nuclear progestin receptor (Pgr) knockouts resulted in subfertility in male tilapia (Oreochromis niloticus).

It was documented that 17α, 20ß-dihydroxy-4-pregnen-3-one (DHP), a fish specific progestin, might play critical roles in spermatogenesis, sperm maturation and spermiation partially through activating nuclear receptor (Pgr). However, no direct evidence is available to demonstrate the functions of DHP in fish spermatogenesis. To further elucidate the roles of DHP in teleosts, we generated a pgr homozygous mutant line in XY Nile tilapia (Oreochromis niloticus). Pgr gene mutation resulted in the development of a smaller, thinner testis and a lower GSI compared with normal testis. Pgr gene knockout led to irregular arrangement of spermatogenic cysts, decline of sperm count and sperm motility. Significant decrease of spermatocytes and spermatozoa was observed, which was further proved by the PCNA and Ph3 staining. Real-time PCR analysis demonstrated that mutation of pgr gene resulted in a significant up-regulation of steroidogenesis-related genes of cyp17a, cyp11b2, StAR, scc, 20ß-HSD, and sf1, and down-regulation of fshb, fshr, oct4, sycp3, cdk1, prm, cyclinB1, cyclinB2 and cdc25 genes. Furthermore, both Immunohistochemistry and Western blotting experiments revealed a remarkable increase of Cyp17a1, Cyp17a2 and Cyp11b2 expressions in the pgr-/- testis. EIA measurement showed that an evident increase of 11-KT level was found in the pgr-/- XY fish. There was a significant increase in the mortality of offspring when crossing pgr-/- XY fish with wild type XX fish. Increased TUNEL staining and enhanced apoptosis maker gene (bax) expressions were also observed. Taken together, our data suggested that DHP-activated physiology via pgr is crucial for the fertility in the XY tilapia.

Mechanism of photoisomerization of 1-naphthyl-2-phenylethylenes in organic glasses.

Photoisomerization reactions of cis isomers of 1-beta-naphthyl-2-phenylethylene, an o-methylated homolog and 1-alpha-naphthyl-2-phenylethylene in organic glasses at liquid nitrogen temperature were studied. Reactions were followed by changes in UV-absorption spectra of the irradiated samples. Formation of an unstable trans-photoproduct was detected only with the o-methylated homolog. The results are consistent with high regioselective Hula-twist photoisomerization at the benzylic sites of the three compounds examined. Calculated data on relative energies of the conformers of both the cis and the trans isomers are in agreement with the suspected conformational population of the starting materials and the photoproducts.

Mechanisms of photoisomerization of polyenes in confined media: from organic glasses to protein binding cavities.

Photochemical reactivities of model organic systems (stilbene and diphenylbutadiene) in organic glasses were first examined and compared with those in solution and in organized media. These observations were in turn compared with reactivities of polyene chromophores in protein binding cavities (specifically PYP, rhodopsin and bacteriorhodopsin). The obvious conclusion is that the preference for the most volume-conserving Hula-twist mechanism isomerization in organic glasses is because of the close interaction between the guest and the host molecules. In organized media (zeolites, crystals and protein binding cavities), the residual empty space coupled with any specific guest-host interactions that are characteristic of a given system, could lead to involvement of the more volume-demanding one-bond-flip (i.e. torsional relaxation) or bicycle-pedal or an extended HT process in photoisomerization.

Spectroscopic and computational studies on the coordination-driven self-assembly complexes (ZnL)2 and (NiL)2 [L= bis(2,4-dimethyldipyrrin-3-yl)methane].

FT-IR, FT-Raman and electronic absorption spectroscopies were utilized in conjunction with density functional theory (DFT) calculations to investigate the ground and excited states of self-assembled dinuclear dimeric helicates (ZnL)2 and (NiL)2 [L = bis(2,4-dimethyldipyrrin-3-yl)methane]. These studies afford a detailed description of the ground-state geometric and electronic structures of (ZnL)2 and (NiL)2 and provide a comparison with similar geometrical metal-porphyrins. The results demonstrate that enlarging the basis set used in the DFT calculations results in an obvious alteration of the calculated bond lengths but negligible alteration of the calculated bond angles. The predicted spectra are in good agreement with the experimental ones with the deviations generally less than 30 cm(-1). In comparison with vibrational spectra of metal-porphyrins, the breathing vibration of the pyrrole ring is shifted by over 100 cm(-1) toward higher wavenumber due to local conjugation of molecular geometry. Time-dependent density functional theory (TD-DFT) provides a good description of the excitation energy. Because of the break in symmetry, the absorption band (corresponding to the Q-band of porphyrin) of (ZnL)2 and (NiL)2 is no longer weak. Local conjugation makes the absorption wavelength of (NiL)2 and (ZnL)2 shift to the blue compared with those of NiP and ZnP.

Stilbene analogs in Hula-twist photoisomerization.

Photoisomerization of several cis- or Z-stilbene analogs and two E-analogs in low temperature organic glasses was examined. From a mechanistic view-point, the compounds can be divided into three types: (i) those giving identical Hula-twist (HT) and one-bond-flip (OBF) products, (ii) those giving a single HT product that is different (hence distinguishable) from the OBF product and (iii) those showing two distinct HT processes but only one OBF process. Examples for all three types of analogs are provided emphasizing the most informative Type-II (stilbene analogs with identical but unsymmetrically substituted phenyl rings), including linear as well as conformationally constrained compounds. Conditions necessary for establishing HT and OBF processes are defined. Proper choice and design of model systems are essential for establishing or eliminating HT mechanism(s) of isomerization.

Photophysical properties of diphenyl-2,3-dihydroxychlorin and diphenylchlorin.

The photophysical properties of 5,15-diphenyl-2,3-dihydroxychlorin (DPCOH) and 5,15-diphenyl-chlorin (DPC) in organic solution were studied. Absorption, fluorescence, triplet state and photobleaching experiments are reported. The ground states of both compounds show strong absorbance in red region (lambda = 638 nm, epsilon = 35,000 M(-1) cm(-1) and lambda = 645 nm, epsilon = 42,000 M(-1) cm(-1), respectively) and the singlet excited states show low fluorescence quantum yields of 0.0802 and 0.150 in benzene and the lifetimes are 7.38 and 10.18 ns, respectively. Absorption spectra of the triplet states were also measured and they have nearly the same triplet state lifetimes of 53 micros (DPCOH) and 50 micros (DPC). The triplet quantum yields are 0.82 and 0.75, respectively. The data of photobleaching quantum yields show that the presence of oxygen does not significantly affect the photobleaching. All the results demonstrate that both diphenylchlorines are good candidates for second-generation photosensitizer in photodynamic therapy.