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OBJECTIVE: To investigate the impact of response to induction chemotherapy (IC) on survival outcomes in patients with locally advanced nasopharyngeal carcinoma (LANPC) and evaluate the efficacy of adding nimotuzumab to concurrent chemoradiotherapy (CCRT) based on different responses to IC. METHODS: We retrospectively included patients with stage III-IVA NPC who underwent IC with and without nimotuzumab during CCRT. Statistical analysis included the chi-square test, propensity score matching, Kaplan-Meier survival analysis, and Cox proportional hazards model. RESULTS: Among 383 identified patients, 216 (56.4%) received nimotuzumab during CCRT, while 167 (43.6%) did not. Following IC, 269 (70.2%) patients showed a complete response (CR) or partial response (PR), and 114 (29.8%) had stable disease (SD) or progressive disease (PD). The response to IC independently influenced disease-free survival (DFS) and overall survival (OS). Patients achieving CR/PR demonstrated significantly higher 3-year DFS (80.3% vs. 70.6%, P = 0.031) and OS (90.9% vs. 83.2%, P = 0.038) than those with SD/PD. The addition of nimotuzumab during CCRT significantly improved DFS (P = 0.006) and OS (P = 0.037) for CR/PR patients but not for those with SD/PD. CONCLUSIONS: This study emphasizes the importance of IC response in LANPC and highlights the potential benefits of nimotuzumab during CCRT for improving survival outcomes in CR/PR patients. Tailored treatment approaches for SD/PD patients warrant further investigation.
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Anticuerpos Monoclonales Humanizados , Quimioradioterapia , Quimioterapia de Inducción , Carcinoma Nasofaríngeo , Neoplasias Nasofaríngeas , Humanos , Masculino , Femenino , Carcinoma Nasofaríngeo/terapia , Carcinoma Nasofaríngeo/mortalidad , Carcinoma Nasofaríngeo/tratamiento farmacológico , Carcinoma Nasofaríngeo/patología , Quimioradioterapia/métodos , Quimioterapia de Inducción/métodos , Persona de Mediana Edad , Anticuerpos Monoclonales Humanizados/uso terapéutico , Anticuerpos Monoclonales Humanizados/administración & dosificación , Estudios Retrospectivos , Neoplasias Nasofaríngeas/terapia , Neoplasias Nasofaríngeas/mortalidad , Neoplasias Nasofaríngeas/patología , Neoplasias Nasofaríngeas/tratamiento farmacológico , Adulto , Anciano , Estadificación de Neoplasias , Resultado del Tratamiento , Estimación de Kaplan-Meier , Antineoplásicos Inmunológicos/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Supervivencia sin Enfermedad , Adulto JovenRESUMEN
To construct an artificial intelligence system with high efficient information integration and computing capability like the human brain, it is necessary to realize the biological neurotransmission and information processing in artificial neural network (ANN), rather than a single electronic synapse as most reports. Because the power consumption of single synaptic event is â¼10 fJ in biology, designing an intelligent memristors-based 3D ANN with energy consumption lower than femtojoule-level (e.g., attojoule-level) and faster operating speed than millisecond-level makes it possible for constructing a higher energy efficient and higher speed computing system than the human brain. In this paper, a flexible 3D crossbar memristor array is presented, exhibiting the multilevel information transmission functionality with the power consumption of 4.28 aJ and the response speed of 50 ns per synaptic event. This work is a significant step toward the development of an ultrahigh efficient and ultrahigh-speed wearable 3D neuromorphic computing system.
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DYRK1A is considered a potential cancer therapeutic target, but the role of DYRK1A in NSCLC oncogenesis and treatment requires further investigation. In our study, high DYRK1A expression was observed in tumour samples from patients with lung cancer compared with normal lung tissues, and the high levels of DYRK1A were related to a reduced survival time in patients with lung cancer. Meanwhile, the DYRK1A inhibitor harmine could suppress the proliferation of NSCLC cells compared to that of the control. As DYRK1A suppression might be effective in treating NSCLC, we next explored the possible specific molecular mechanisms that were involved. We showed that DYRK1A suppression by siRNA could suppress the levels of EGFR and Met in NSCLC cells. Furthermore, DYRK1A siRNA could inhibit the expression and nuclear translocation of STAT3. Meanwhile, harmine could also regulate the STAT3/EGFR/Met signalling pathway in human NSCLC cells. AZD9291 is effective to treat NSCLC patients with EGFR-sensitivity mutation and T790âM resistance mutation, but the clinical efficacy in patients with wild-type EGFR remains modest. We showed that DYRK1A repression could enhance the anti-cancer effect of AZD9291 by inducing apoptosis and suppressing cell proliferation in EGFR wild-type NSCLC cells. In addition, harmine could enhance the anti-NSCLC activity of AZD9291 by modulating STAT3 pathway. Finally, harmine could enhance the anti-cancer activity of AZD9291 in primary NSCLC cells. Collectively, targeting DYRK1A might be an attractive target for AZD9291 sensitization in EGFR wild-type NSCLC patients.
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Acrilamidas/farmacología , Compuestos de Anilina/farmacología , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Neoplasias Pulmonares/tratamiento farmacológico , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-met/metabolismo , Factor de Transcripción STAT3/metabolismo , Apoptosis/efectos de los fármacos , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Resistencia a Antineoplásicos/efectos de los fármacos , Receptores ErbB/metabolismo , Humanos , Neoplasias Pulmonares/metabolismo , Transducción de Señal/efectos de los fármacos , Quinasas DyrKRESUMEN
A series of Pt(II)-Schiff base complexes were synthesized as triplet sensitizers for the purpose of tuning the singlet and triplet energy levels so as to minimize energy loss during triplet-triplet annihilation (TTA) upconversion (UC). A deep-red to blue TTA-UC was achieved with an unprecedentedly large anti-Stokes shift of 1.08 eV. UC quantum yields of up to 21% (with a theoretical maximum efficiency of 50%) were observed in solution. The complexes also showed efficient UC emission in air-saturated hydrogels with a UC quantum yield up to 14.8%, which is much higher than the highest previously reported value. The low threshold excitation intensity provided by the present system offers promising potential for application in terrestrial solar energy conversion.
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Stereoisomeric ß-cyclodextrin (CD) dimers linked with a sulfur atom or an arene spacer were designed to create a tethered dual CD capsule for precisely manipulating the regio- and enantioselectivities of the photocyclodimerization of 2-anthracenecarboxylate (AC) to four stereoisomeric classical 9,10:9',10'-cyclodimers and two nonclassical 5,8:9',10'-cyclodimers. Among the dimeric CD hosts prepared, exo-3-thia-ß-CD dimer formed 1:1 and 1:2 host-guest complexes with AC in aqueous solutions, the former of which hindered but the latter facilitated the AC photocyclodimerization with regio- and enantioselectivities much higher than those obtained with native ß-CD or the rest of the ß-CD dimers. The stereochemical outcomes turned out to be highly sensitive to and hence critically manipulable by the linking position and configuration of the connected saccharide units and the linker length, as well as the external variants, such as temperature, pH, and added salt. Eventually, the photocyclodimerization of AC mediated by the dimeric ß-CD host gave enantiopure syn-head-to-tail-9,10:9',10'-cyclodimer in 97-98% yield in a pH 5.1 buffer solution at 0.5 °C and also in an aqueous CsCl solution at -20 °C.
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Visible-light-driven photocatalytic supramolecular enantiodifferentiating dimerization of 2-anthracenecarboxylic acid (AC) through triplet-triplet annihilation (TTA), mediated by the Schiff base Pt(II) complex (Pt-1, Pt-2, and Pt-3) was studied. The host concentration and the temperature effects on the stereoselectivity were comprehensively investigated. Increasing the concentration of sensitizers/hosts significantly enhanced the conversion of the photoreaction but led to reduced enantioselectivities of the chiral photodimers 2 and 3 when the photoreaction was triggered by a 532 nm laser, which was in contrast with the results obtained by direct irradiation of AC with a 365 nm light-emitting diode (LED) lamp, due to the aggregation of the sensitizer/host in water. The cyclization of AC through triplet-triplet annihilation displayed significant temperature dependency when Pt-3 was employed as the sensitizer/host. Increasing the temperature from 0 °C to 30 °C with 5% equiv. of Pt-3 led to a great increase of the ee of 2 from 2.1% to 31.6%. However, hardly any temperature dependency was observed when the photodimerization was mediated by other sensitizers and/or hosts, or the photoreaction was triggered directly with a 365 nm LED lamp.
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Antracenos/química , Ácidos Carboxílicos/química , Ciclodextrinas/química , Dimerización , Calor , Procesos Fotoquímicos , CiclizaciónRESUMEN
Hypoxia promotes HCC progression and therapy resistance, and there is no systemic treatment for HCC patients after sorafenib resistance. Thus, it is urgent to develop potential therapeutic regimens for HCC patients by targeting hypoxia signaling. In this study, we showed that evodiamine might be a potential therapeutic medicine for HCC by suppressing HIF-1α. In addition, evodiamine could sensitize the anti-HCC effect of vorinostat in HCC cells under hypoxia. Furthermore, evodiamine plus vorinostat accelerated the degradation of HIF-1α in HCC cells under hypoxia. In general, evodiamine might be a potential therapeutic candidate for HCC patients, and evodiamine combining with vorinostat might be an attractive chemotherapy strategy for HCC treatment.
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Antineoplásicos/farmacología , Carcinoma Hepatocelular/tratamiento farmacológico , Ácidos Hidroxámicos/farmacología , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Hipoxia/tratamiento farmacológico , Neoplasias Hepáticas/tratamiento farmacológico , Quinazolinas/farmacología , Antineoplásicos Fitogénicos/farmacología , Apoptosis/efectos de los fármacos , Carcinoma Hepatocelular/complicaciones , Carcinoma Hepatocelular/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Regulación hacia Abajo/efectos de los fármacos , Sinergismo Farmacológico , Humanos , Hipoxia/complicaciones , Hipoxia/metabolismo , Subunidad alfa del Factor 1 Inducible por Hipoxia/análisis , Neoplasias Hepáticas/complicaciones , Neoplasias Hepáticas/metabolismo , VorinostatRESUMEN
Water-soluble 9,10-diphenylanthracene-modified γ-cyclodextrin derivatives A1 and A2, in which the γ-cyclodextrin unit serves as a molecular host for a binding sensitizer, and the 9,10-diphenylanthracene moiety plays a role as an emitter/annihilator, were synthesized to investigate the supramolecular triplet-triplet annihilation (TTA) upconversion in aqueous solution. Both A1 and A2 readily aggregate and form nanoscale assemblies in water as a combined result of host-guest complexation and π-π stacking among the 9,10-diphenylanthracenes. The aggregation behavior of the supramolecular emitters was fully characterized by using a diversity of methods, including dynamic light scattering (DLS), SEM, NMR, fluorescence, and circular dichroism studies. Fluorescence spectroscopic analysis reveals that the emitters have high fluorescence quantum yields in water (82 and 90 % for A1 and A2, respectively), thus demonstrating that aggregation does not quench the fluorescence. By using a coordinated ruthenium sensitizer, a high TTA upconversion quantum yield of up to 6.9 % was observed for this supramolecular TTA system, which is significantly higher than the value (<0.5 %) obtained with nonassembled emitters in organic solvent and in contrast to the fact that TTA upconversion emission in aqueous solution is usually low or negligible. We ascribe the strong TTA upconversion emission in the present supramolecular assembly system to an efficient TTA process, which is facilitated along the stacked emitters by triplet energy migration and improved triplet-triplet energy transfer through host-guest complexation.
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The purpose of this study was to investigate the relationship between circulating cytokines and liver function and prognosis of patients with advanced hepatocellular carcinoma (HCC) treated with radiotherapy combined with tislelizumab and anlotinib. The liver function indexes and pre-treatment levels of cytokines in 47 patients were measured by chemical method and flow cytometry. The median follow-up was 23.1 months. The objective response and the disease control rates were 46.8% and 68.1%, while overall survival (OS) and progression-free survival (PFS) were 12.6 and 11.4 months, respectively. Adverse events (2.1%) were grade 3-4. In addition to stage, intrahepatic metastasis and Child-Pugh score, pre-treatment interleukin-6 (IL-6) was the main cytokine affecting OS and PFS (p < 0.05). The OS (14.63 pg/mL as cutoff value) and PFS (9.85 pg/mL as cutoff value) of patients with low IL-6 levels exceeded those with high levels (21.0 and 6.9, 15.8 and 10.0 months, respectively). The risks of death and disease progression were reduced by 63.0% (HR = 0.37, 95% CI: 0.19-0.72) and 43.0% (HR = 0.57, 95% CI: 0.22-1.47), respectively. Pre-treatment IL-6 levels may be a simple and effective prognostic indicator for patients with advanced HCC treated with radiotherapy combined with immunotargeted therapy.
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Anticuerpos Monoclonales Humanizados , Carcinoma Hepatocelular , Citocinas , Indoles , Neoplasias Hepáticas , Quinolinas , Humanos , Carcinoma Hepatocelular/tratamiento farmacológico , Carcinoma Hepatocelular/radioterapia , Carcinoma Hepatocelular/mortalidad , Carcinoma Hepatocelular/patología , Neoplasias Hepáticas/radioterapia , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/mortalidad , Masculino , Femenino , Persona de Mediana Edad , Quinolinas/uso terapéutico , Quinolinas/administración & dosificación , Anticuerpos Monoclonales Humanizados/uso terapéutico , Anticuerpos Monoclonales Humanizados/administración & dosificación , Anciano , Indoles/uso terapéutico , Indoles/administración & dosificación , Pronóstico , Citocinas/sangre , Adulto , Interleucina-6/sangre , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversosRESUMEN
BACKGROUND: To investigate the prevalence and predictive factors of xerostomia during induction chemotherapy (IC) in patients with nasopharyngeal carcinoma (NPC). METHODS: We prospectively enrolled NPC patients who received IC between October 2020 and October 2021. The Visual Analogue Scale (VAS) and Xerostomia Inventory (XI) were used to evaluate the condition of xerostomia. The volume of the submandibular gland (SMG) was also calculated before and after IC. RESULTS: Fifty-two patients were enrolled in this study. Of these patients, 32.7% (n = 17) experienced xerostomia before IC. There were 32 (61.5%) patients suffered from xerostomia after IC, including 21 (40.4%) patients with newly diagnosed xerostomia after IC and 11 (21.1%) patients complained their xerostomia aggravated in those with xerostomia before IC. The median XI scores increased from 11 (standard deviation [SD], 2.930) to 18 (SD 3.995), 16 (SD 3.605), and 17 (SD 4.331) after the first, second, and third cycles of IC, respectively. The median score of VAS also increased from 0 to 4 during the following three cycles of IC. In those with IC-related xerostomia, the SMG volume after IC was significantly decreased compared with those without IC-related xerostomia (P = 0.001). The reduction of the SMG volume after IC was the independent risk factor for xerostomia (P = 0.002). CONCLUSION: Approximately two-thirds of NPC patients suffered from IC-related xerostomia and patients with a reduction of SMG volume after IC had a higher risk of xerostomia.
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Neoplasias Nasofaríngeas , Xerostomía , Humanos , Carcinoma Nasofaríngeo/patología , Neoplasias Nasofaríngeas/tratamiento farmacológico , Neoplasias Nasofaríngeas/complicaciones , Quimioterapia de Inducción/efectos adversos , Xerostomía/inducido químicamente , Xerostomía/epidemiología , Glándula Submandibular/patologíaRESUMEN
BACKGROUND: Thyroid hormones (THs) and thyroid-stimulating hormone (TSH) seem to show high potential in predicting the clinical death outcome of patients admitted to the intensive care unit (ICU). However, diverse studies on this topic are conflicting. METHODS: A search was conducted by two investigators involved in this research in the PubMed, Embase, and Cochrane databases (all last launched on July 12, 2021). The quality of the included studies was evaluated using the Newcastle-Ottawa Quality Assessment Scale (NOS). Subgroup analyses were performed to determine the sources of heterogeneity. Sensitivity and publication bias analyses were also assessed. RESULTS: A total of 27 studies (4970 participants) were included based on the eligibility criteria. Compared with survivors, nonsurvivors were found to have lower levels of THs (T3, T4, fT3, and fT4), whereas no significant difference was found in TSH levels (13 studies for T3: standardized mean differences [SMD], -0.78; 95% CI, -1.36 to -0.20; I2 = 96%; p = 0.008; 11 studies for T4: SMD = -0.79; 95% CI, -1.31 to -0.28; I2 =95%; p = 0.0002; 14 studies for fT3: SMD = -0.76; 95% CI, -1.21 to -0.32; I2 = 95%; p = 0.0008; 17 studies for fT4: SMD = -0.60; 95% CI, -0.99 to -0.22; I2 = 95%; p = 0.002; 20 studies for TSH: SMD = 0.00; 93% CI, -0.29 to 0.29; I2 = 93%; p = 0.98). CONCLUSION: Nonsurvivors were associated with lower levels of THs (T3, T4, fT3, and fT4) than survivors. THs show great application potential in predicting ICU patients' death outcomes and improving already widely used prognostic scores in the ICU (ie, Acute Physiological and Chronic Health Evaluation [APACHE] II and Therapeutic Intervention Scoring System).
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Tirotropina , Tiroxina , Adulto , Hospitalización , Humanos , Unidades de Cuidados Intensivos , Hormonas TiroideasRESUMEN
The low quantum efficiency in the solid phase and the highly efficient quenching by oxygen are two major weaknesses limiting the practical applications of triplet-triplet annihilation (TTA) upconversion (UC). Herein, we report an organic-inorganic hybrid nanocomposites fabricated by self-assembly of LAPONITE® clay and poly(N-vinyl-2-pyrrolidone) (PVP), which serves as excellent matrix for solid-state TTA-UC even in air. In the hybrid hydrogel doped by TTA-UC components, the anionic acceptors are arranged in an ordered manner at the nano-disk edge through electrostatic attraction, which avoids haphazard accumulation of the acceptors and allows for highly efficient inter-acceptor triplet energy migration. Moreover, the entangled PVP could not only protect the triplet excitons from oxygen quenching but even proactively eliminate oxygen by photoirradiation. Significantly, the dried gel prepared by completely removing water from the hydrogel gave absolute UC quantum efficiencies of up to 23.8% (out of a 50% maximum), which is the highest TTA-UC efficiency obtained in the solid state. The dried gels are readily made into powder by grinding with maintained UC emissions, making them convenient for application to information encryption and anti-counterfeiting security by virtue of the high UC quantum efficiency and insensitivity to oxygen.
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Nanocompuestos , Arcilla , Hidrogeles , OxígenoRESUMEN
Photochemical methods are increasingly being used in organic synthesis. They are especially useful for preparing many compounds that are not readily accessible through thermal or enzymatic reactions. The supramolecular strategy has proved highly promising in recent years for manipulating the stereochemical outcome of chiral photoreactions through relatively strong and long-lasting noncovalent interactions in both ground and excited states. Among the numerous chiral photochemical reactions, photocyclodimerization of 2-anthracenecarboxylate (AC) is the most comprehensively studied supramolecular chiral photoreaction and has essentially become a benchmark reaction for evaluating supramolecular photochirogenesis. Cyclodextrin (CD) derivatives were the earliest and are the most widely applied chiral host for mediating photoreactions. Herein, we use CD-mediated photocyclodimerization of AC as an example to introduce the operation process of supramolecular chiral photoreactions. The protocol includes the following contents: (i) the preparation, purification and characterization of ß-CD derivatives; (ii) methods for investigating the host-guest inclusion behavior between AC and ß-CD derivatives; (iii) the photochemical reaction operation flow under different solvent and temperature conditions; (iv) chiral high-performance liquid chromatography (HPLC) analyses of the product distribution and enantioselectivity. The protocol is introduced by using representative examples of the synthesis of ß-CD derivatives and the manipulation of environmental factors that give excellent regio- and enantioselectivities in the photocyclodimerization of AC. The synthesis and purification of ß-CD derivatives require 3-5 d of work. The photoirradiation of AC with ß-CD derivatives can be done within 1 h. The product analysis requires 5 h.
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Ciclodextrinas , Estereoisomerismo , Dimerización , CiclizaciónRESUMEN
Purpose: To assess the causes of death (COD) and long-term survival after nasopharyngeal carcinoma (NPC) diagnosis. Methods: Using linked data from the Surveillance, Epidemiology, and End Results program, patients with NPC diagnosed from 1990 to 2010 and followed up >5 years were identified. Chi-squared test, the Kaplan-Meier method, and the Cox proportional hazard model were used for analyses. Results: Among the 3,036 long-term NPC survivors, 1,432 survived for >5-10 years and 1,604 survived for >10 years. The most common COD was primary NPC (36.9%), followed by other causes (28.7%), other cancers (15.3%), cardiac disease (12.9%), and non-malignant pulmonary disease (6.2%). With a median follow-up of 125 months, deaths from NPC decreased with increasing time from diagnosis, while death because of cardiac disease and other causes increased. In those aged <50 years, death due to NPC remained the main COD over time, while cardiopulmonary disease-related death was the leading COD in patients aged ≥50 years. In White patients, death due to NPC decreased, and death due to cardiac disease increased over time. Death from NPC remained significant in Black and Asian patients even 15 years after the diagnosis of NPC, while death due to cardiac disease significantly increased after 9 years of diagnosis in Black patients. Multivariate analyses showed that the independent factors associated with inferior NPC-specific survival were older age, Asians, American Indian/Alaska Native, regional stage, distant stage, and diagnosis in the early years. Conclusions: The probability of death from primary NPC remains significant even 15 years after the NPC diagnosis. Our study advocates continued surveillance for NPC survivors beyond the traditional 5 years. Individualized follow-up strategies are required for patients with NPC of different ages and races.
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Cardiopatías , Neoplasias Nasofaríngeas , Causas de Muerte , Humanos , Carcinoma Nasofaríngeo/patología , Neoplasias Nasofaríngeas/patología , SobrevivientesRESUMEN
Singlet chiral photocatalysis is highly challenging. Herein, we report fluorescence resonance energy transfer (FRET)-based chiral photocatalysis with γ-cyclodextrin (CD)-grafted lanthanide-doped upconverted nanoparticles (UCNP). The CD-modified UCNP strongly emits in the UV wavelength region upon excitation with a 980 nm laser, which selectively sensitizes the photosubstrates complexed by CD on the surface of UCNP through FRET. Therefore, enantiodifferentiating photocyclodimerization of anthracene or naphthalene derivatives sensitized by the CD-modified UCNP gives photoproducts in good enantioselectivity even in the presence of a catalytic amount of CD-modified UCNP. Moreover, the photocatalysts are readily separated and could be reused for at least six cycles without decreasing the enantioselectivity.
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Several sulfoxide- and sulfone-bridged ß-cyclodextrin (CD) dimers were synthesized for mediating the enantiodifferentiating [4+4] photocyclodimerization of 2-anthracenecarboxylic acid (AC). The complexation behavior of these chiral hosts with AC was investigated by UV-vis, circular dichroism, fluorescence, and NMR spectroscopies and certified the formation of 1 : 1 and 1 : 2 host-guest complexes. The product distribution and enantioselectivity of the photoreaction turned out to be a critical function of the chemical structure of bridged CDs. Comparing to the sulfur-bridged 2AX -3GX ß-CD dimer 7, the conversion of the photolyzes with sulfoxide-bridged was significantly improved, and the ee of cyclodimer 2 was remarkably increased from -82.8% with 7 to -96.7% with the sulfoxide-bridged 2AX -3GX ß-CD dimer 8. The relative yields and ee values of the slipped cyclodimers 5 and 6 were greatly enhanced in the presence of 6â M CsCl. The reaction selectivity is susceptible to the pH variation of the aqueous buffer solution, demonstrating that the supramolecular photochirogenesis is controlled by multidimensional factors, including the chemical structure of the chiral host, solvent, and pH conditions.
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Antracenos/química , Ácidos Carboxílicos/química , beta-Ciclodextrinas/química , Dimerización , Concentración de Iones de Hidrógeno , Sustancias Macromoleculares/síntesis química , Sustancias Macromoleculares/química , Estructura Molecular , Procesos Fotoquímicos , Solventes/química , EstereoisomerismoRESUMEN
Tri-cavity hosts consisting of one pillar[5]arene (P5) sandwiched by two ß-cyclodextrins (CDs) were synthesized, and their diastereoseparation was successfully accomplished. Photocyclodimerization of 2-anthracenecarboxylate with these hybrid hosts demonstrated the critical dependence of stereoselectivity on the absolute configuration of the central P5 and the conjugating positions on the ß-CD, and gave the non-classical HT photodimers in up to 87% ee.
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Several γ-cyclodextrin (γ-CDx) derivatives were used as chiral hosts for the photocyclodimerization of 2-anthracenecarboxylic acid (AC). The effect of pH on photoreactivity and stereochemical outcome of photoproducts was investigated. Upon changing the solution pH, the stereochemical outcome of HH cyclodimer 3 was inverted from 25.2% to -64.4% and 41.2% to -76.2%, respectively, in the photocyclodimerization of AC mediated by bis-quinoline-modified γ-CDx 7 and its N-methylated derivative 8.
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The design and development of specific recognition and sensing systems for biologically important anionic species has received growing attention in recent years, as they play significant roles in biology, pharmacy, and environmental sciences. Herein, a new supramolecular sensing probe L1 was developed for highly selective differentiation of nucleotides. L1 displayed extremely marked absorption and emission differentiation upon binding with nucleotide homologs of AMP, ADP, and ATP, due to the divergent spatial orientations of guests upon binding, which allowed for a naked-eye colorimetric differentiation for nucleotides. A differentiating mechanism was unambiguously rationalized by using various spectroscopic studies and theoretical calculations. Furthermore, we successfully demonstrated that L1 can be applied to the real-time monitoring of the enzyme-catalyzed phosphorylation/dephosphorylation processes and thus demonstrated an unprecedented visualizable strategy for selectively differentiating the structurally similar nucleotides and real-time monitoring of biological processes via fluorescent and colorimetric changes.
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An amendment to this paper has been published and can be accessed via a link at the top of the paper.