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1.
Nature ; 2024 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-38885695

RESUMEN

Oligosaccharides have myriad functions throughout biology.1,2 To investigate these functions requires multi-step chemical synthesis of these structurally complex molecules. With a dense concentration of stereocentres and hydroxyl groups, oligosaccharide assembly through O-glycosylation requires simultaneous control of site-, stereo-, and chemoselectivities3,4. Chemists have traditionally relied on protecting group manipulations for this purpose,5-8 adding a lot of synthetic work. Here, we report a glycosylation platform that enables selective coupling between unprotected or minimally protected donor and acceptor sugars, producing 1,2-cis-O-glycosides in a catalyst-controlled, site-selective manner. Radical-based activation9 of allyl glycosyl sulfones forms glycosyl bromides. A designed aminoboronic acid catalysts bring this reactive intermediate close to an acceptor through a network of noncovalent hydrogen bonding and reversible covalent B-O bonding interactions, allowing precise glycosyl transfer. The site of glycosylation can be switched with different aminoboronic acid catalysts by affecting their interaction modes with substrates. The method accommodates a wide range of sugar types, amenable to preparing naturally occurring sugar chains and pentasaccharides containing 11 free hydroxyls. Experimental and computational studies provide insights into the origin of selectivity outcomes.

2.
Chem Rev ; 123(16): 9940-9981, 2023 08 23.
Artículo en Inglés | MEDLINE | ID: mdl-37561162

RESUMEN

A survey of protein databases indicates that the majority of enzymes exist in oligomeric forms, with about half of those found in the UniProt database being homodimeric. Understanding why many enzymes are in their dimeric form is imperative. Recent developments in experimental and computational techniques have allowed for a deeper comprehension of the cooperative interactions between the subunits of dimeric enzymes. This review aims to succinctly summarize these recent advancements by providing an overview of experimental and theoretical methods, as well as an understanding of cooperativity in substrate binding and the molecular mechanisms of cooperative catalysis within homodimeric enzymes. Focus is set upon the beneficial effects of dimerization and cooperative catalysis. These advancements not only provide essential case studies and theoretical support for comprehending dimeric enzyme catalysis but also serve as a foundation for designing highly efficient catalysts, such as dimeric organic catalysts. Moreover, these developments have significant implications for drug design, as exemplified by Paxlovid, which was designed for the homodimeric main protease of SARS-CoV-2.


Asunto(s)
COVID-19 , Humanos , SARS-CoV-2 , Polímeros
3.
Circulation ; 147(17): 1264-1276, 2023 04 25.
Artículo en Inglés | MEDLINE | ID: mdl-36866664

RESUMEN

BACKGROUND: Concerns have been raised about the long-term performance of aortic stent grafts for the treatment of abdominal aortic aneurysms, in particular, unibody stent grafts (eg, Endologix AFX AAA stent grafts). Only limited data sets are available to evaluate the long-term risks related to these devices. The SAFE-AAA Study (Comparison of Unibody and Non-Unibody Endografts for Abdominal Aortic Aneurysm Repair in Medicare Beneficiaries Study) was designed with the Food and Drug Administration to provide a longitudinal assessment of the safety of unibody aortic stent grafts among Medicare beneficiaries. METHODS: The SAFE-AAA Study was a prespecified, retrospective cohort study evaluating whether unibody aortic stent grafts are noninferior to non-unibody aortic stent grafts with respect to the composite primary outcome of aortic reintervention, rupture, and mortality. Procedures were evaluated from August 1, 2011, through December 31, 2017. The primary end point was evaluated through December 31, 2019. Inverse probability weighting was used to account for imbalances in observed characteristics. Sensitivity analyses were used to evaluate the effect of unmeasured confounding, including assessment of the falsification end points heart failure, stroke, and pneumonia. A prespecified subgroup included patients treated from February 22, 2016, through December 31, 2017, corresponding to the market release of the most contemporary unibody aortic stent grafts (Endologix AFX2 AAA stent graft). RESULTS: Of 87 163 patients who underwent aortic stent grafting at 2146 US hospitals, 11 903 (13.7%) received a unibody device. The average age of the total cohort was 77.0±6.7 years, 21.1% were female, 93.5% were White, 90.8% had hypertension, and 35.8% used tobacco. The primary end point occurred in 73.4% of unibody device-treated patients versus 65.0% of non-unibody device-treated patients (hazard ratio, 1.19 [95% CI, 1.15-1.22]; noninferior P value of 1.00; median follow-up, 3.4 years). Falsification end points were negligibly different between groups. In the subgroup treated with contemporary unibody aortic stent grafts, the cumulative incidence of the primary end point occurred in 37.5% of unibody device-treated patients and 32.7% of non-unibody device-treated patients (hazard ratio, 1.06 [95% CI, 0.98-1.14]). CONCLUSIONS: In the SAFE-AAA Study, unibody aortic stent grafts failed to meet noninferiority compared with non-unibody aortic stent grafts with respect to aortic reintervention, rupture, and mortality. These data support the urgency of instituting a prospective longitudinal surveillance program for monitoring safety events related to aortic stent grafts.


Asunto(s)
Aneurisma de la Aorta Abdominal , Implantación de Prótesis Vascular , Procedimientos Endovasculares , Humanos , Femenino , Anciano , Estados Unidos , Anciano de 80 o más Años , Masculino , Prótesis Vascular , Implantación de Prótesis Vascular/efectos adversos , Estudios Retrospectivos , Estudios Prospectivos , Resultado del Tratamiento , Procedimientos Endovasculares/efectos adversos , Medicare , Stents , Diseño de Prótesis
4.
J Org Chem ; 89(7): 5060-5068, 2024 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-38525894

RESUMEN

Radical cyclization has been demonstrated to be an efficient method to access functionalized heterocycles from easily accessible raw materials. Described herein is the development of a photocatalytic proton-coupled electron transfer (PCET) strategy for the synthesis of isoquinoline-1,3-diones using readily prepared naphthalimide (NI)-based organic photocatalysts. The process features free metal-complex photocatalysts, acids, and mild reaction conditions. This mild radical cyclization protocol has a broad substrate scope and can be effectively applied to a variety of medicinally relevant substrates. Furthermore, control experiments were conducted to elucidate the mechanism of this visible light-induced methodology.

5.
Molecules ; 29(8)2024 Apr 14.
Artículo en Inglés | MEDLINE | ID: mdl-38675603

RESUMEN

Due to boron's metalloid properties, aromatic boron reagents are prevalent synthetic intermediates. The direct borylation of aryl C-H bonds for producing aromatic boron compounds offers an appealing, one-step solution. Despite significant advances in this field, achieving regioselective aryl C-H bond borylation using simple and readily available starting materials still remains a challenge. In this work, we attempted to enhance the reactivity of the electron-donor-acceptor (EDA) complex by selecting different bases to replace the organic base (NEt3) used in our previous research. To our delight, when using NH4HCO3 as the base, we have achieved a mild visible-light-mediated aromatic C-H bond borylation reaction with exceptional regioselectivity (rr > 40:1 to single isomers). Compared with our previous borylation methodologies, this protocol provides a more efficient and broader scope for aryl C-H bond borylation through the use of N-Bromosuccinimide. The protocol's good functional-group tolerance and excellent regioselectivity enable the functionalization of a variety of biologically relevant compounds and novel cascade transformations. Mechanistic experiments and theoretical calculations conducted in this study have indicated that, for certain arenes, the aryl C-H bond borylation might proceed through a new reaction mechanism, which involves the formation of a novel transient EDA complex.

6.
Angew Chem Int Ed Engl ; : e202409332, 2024 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-38887822

RESUMEN

Described herein is a dirhodium(II)-catalyzed silylation of propargyl esters with hydrosilanes, using tertiary amines as axial ligands. By adopting this strategy, a range of versatile and useful allenylsilanes can be achieved with good yields. This reaction not only represents a SN2'-type silylation of the propargyl derivatives bearing a terminal alkyne moiety to synthesize allenylsilanes from simple hydrosilanes, but also represents a new application of dirhodium(II) complexes in catalytic transformation of carbon-carbon triple bond. The highly functionalized allenylsilanes that are produced can be transformed into a series of synthetically useful organic molecules. In this reaction, an intriguing ON-OFF effect of the amine ligand was observed. The reaction almost did not occur (OFF) without addition of Lewis base amine ligand. However, the reaction took place smoothly (ON) after addition of only catalytic amount of amine ligand. Detailed mechanistic studies and density functional theory (DFT) calculations indicate that the reactivity can be delicately improved by the use of tertiary amine. The fine-tuning effect of the tertiary amine is crucial in the formation of the Rh-Si species via a concerted metalation deprotonation (CMD) mechanism and facilitating ß-oxygen elimination.

7.
BMC Genomics ; 24(1): 163, 2023 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-37013486

RESUMEN

BACKGROUND: Epithelium-mesenchymal interactions are involved in odontogenic processes. Previous studies have focused on the intracellular signalling regulatory network in tooth development, but the functions of extracellular regulatory molecules have remained unclear. This study aims to explore the gene profile of extracellular proteoglycans and their glycosaminoglycan chains potentially involved in dental epithelium-mesenchymal interactions using high-throughput sequencing to provide new understanding of early odontogenesis. RESULTS: Whole transcriptome profiles of the mouse dental epithelium and mesenchyme were investigated by RNA sequencing (RNA-seq). A total of 1,281 and 1,582 differentially expressed genes were identified between the dental epithelium and mesenchyme at E11.5 and E13.5, respectively. Enrichment analysis showed that extracellular regions and ECM-receptor interactions were significantly enriched at both E11.5 and E13.5. Polymerase chain reaction analysis confirmed that the extracellular proteoglycan family exhibited distinct changes during epithelium-mesenchymal interactions. Most proteoglycans showed higher transcript levels in the dental mesenchyme, whereas only a few were upregulated in the epithelium at both stages. In addition, 9 proteoglycans showed dynamic expression changes between these two tissue compartments. Gpc4, Sdc2, Spock2, Dcn and Lum were expressed at higher levels in the dental epithelium at E11.5, whereas their expression was significantly higher in the dental mesenchyme at E13.5, which coincides with the odontogenic potential shift. Moreover, the glycosaminoglycan biosynthetic enzymes Ext1, Hs3st1/5, Hs6st2/3, Ndst3 and Sulf1 also exhibited early upregulation in the epithelium but showed markedly higher expression in the mesenchyme after the odontogenic potential shift. CONCLUSION: This study reveals the dynamic expression profile of extracellular proteoglycans and their biosynthetic enzymes during the dental epithelium-mesenchymal interaction. This study offers new insight into the roles of extracellular proteoglycans and their distinct sulfation underlying early odontogenesis.


Asunto(s)
Odontogénesis , Diente , Ratones , Animales , Epitelio/metabolismo , Odontogénesis/genética , Proteoglicanos/genética , Proteoglicanos/metabolismo , Transducción de Señal , Glicosaminoglicanos/metabolismo
8.
Ann Surg Oncol ; 30(5): 2757-2764, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-36774436

RESUMEN

BACKGROUND: Our study aimed to compare the short-term outcomes between robot-assisted segmentectomy (RAS) and video-assisted segmentectomy (VAS) for small pulmonary nodules. METHODS: The study included of 299 segmentectomies (132 RAS and 167 VAS procedures) for small pulmonary nodules between June 2018 and November 2021. The patients were divided into two groups: the RAS group and the VAS group. Propensity score-matching (PSM) analysis was performed to minimize bias. A logistic regression model was performed to identify the independent risk factors associated with complications. RESULTS: Before PSM, the following clinical variables were not balanced: age (P = 0.004), tumor size (P < 0.001), forced expiratory volume for 1 s (FEV1), and FEV1 percentage (P < 0.001). The patients with RAS had a shorter operative time (P = 0.014), less blood loss, a shorter postoperative hospital stay, less use of strong opioids, less drainage on postoperative day 1, and less postoperative total drainage, but more cost (all P < 0.001). Conversion to open surgery was performed for two patients in the VAS group but none in the RAS group. After PSM, 53 pairs were successfully matched. The data again suggested that the patients with RAS had less blood loss, a shorter postoperative hospital stay, and less use of strong opioids, but more cost (all P < 0.001). The operation time also was shorter in the RAS group, with a borderline statistically significant P value (0.053). CONCLUSIONS: In our study, RAS had better short-term outcomes than VAS, indicating a safer and more efficient technique than VAS.


Asunto(s)
Nódulos Pulmonares Múltiples , Robótica , Humanos , Neumonectomía/métodos , Puntaje de Propensión , Mastectomía Segmentaria , Cirugía Torácica Asistida por Video/efectos adversos , Estudios Retrospectivos
9.
Vasc Med ; 28(6): 564-570, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37638877

RESUMEN

BACKGROUND: Persons living with human immunodeficiency virus (HIV, PLWH) have an increased risk of peripheral artery disease (PAD) in comparison to the general population. However, a gap remains in understanding optimal management for this condition. This study assesses longitudinal outcomes associated with peripheral endovascular intervention (PVI) for PAD among PLWH. METHODS: All Medicare fee-for-service patients undergoing femoropopliteal artery PVI between April 1, 2015 and December 31, 2018 were identified and stratified by HIV serostatus. The primary outcome was major adverse limb events (MALE), defined as major amputation or arterial embolism/thrombosis following an index procedure. The subdistribution hazard was used to evaluate the association between HIV serostatus and MALE, accounting for the competing risk of death. Results were adjusted for sociodemographics and major comorbidities. RESULTS: Of 168,553 patients who underwent PVI, 357 (0.21%) were PLWH. The average age was 77.0 ± 7.6 years; 80.3% had hypertension, 70.3% had hyperlipidemia, and 24.6% had tobacco use disorder. Compared to those without HIV, PLWH were younger and had a higher burden of cardiovascular risk factors. MALE were substantially more frequent among PLWH, with a cumulative incidence of 24.6%, compared to 14.5% among those without HIV. The adjusted subdistribution hazard ratio was 1.26 (95% CI 1.00-1.58, p = 0.05). The use of guideline-directed statin therapy was low in both groups in the 90 days following revascularization (57.9% in PLWH vs 58.1% in those without HIV, p = 0.95). CONCLUSION: Among US Medicare beneficiaries, PLWH had poorer long-term outcomes following PVI. Greater attention to the management of symptomatic PAD is warranted for the HIV population, particularly following revascularization.


Asunto(s)
Procedimientos Endovasculares , Infecciones por VIH , Enfermedad Arterial Periférica , Anciano , Humanos , Estados Unidos/epidemiología , Anciano de 80 o más Años , VIH , Factores de Riesgo , Resultado del Tratamiento , Estudios Retrospectivos , Medicare , Enfermedad Arterial Periférica/diagnóstico , Enfermedad Arterial Periférica/epidemiología , Enfermedad Arterial Periférica/terapia , Infecciones por VIH/diagnóstico , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/epidemiología , Procedimientos Endovasculares/efectos adversos
10.
Pacing Clin Electrophysiol ; 46(3): 242-250, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36530151

RESUMEN

AIMS: Frailty is associated with increased morbidity and mortality in patients undergoing left atrial appendage closure (LAAC). This study aimed to compare the performance of two claims-based frailty measures in predicting adverse outcomes following LAAC. METHODS: We identified patients 66 years and older who underwent LAAC between October 1, 2016, and December 31, 2019, in Medicare fee-for-service claims. Frailty was assessed using the previously validated Hospital Frailty Risk Score (HFRS) and Kim Claims-based Frailty Index (CFI). Patients were identified as frail based on HFRS ≥5 and CFI ≥0.25. RESULTS: Of the 21,787 patients who underwent LAAC, frailty was identified in 45.6% by HFRS and 15.4% by CFI. There was modest agreement between the two frailty measures (kappa 0.25, Pearson's correlation 0.62). After adjusting for age, sex, and comorbidities, frailty was associated with higher risk of 30-day mortality, 1-year mortality, 30-day readmission, long hospital stay, and reduced days at home (p < .01 for all) regardless of the frailty measure used. The addition of frailty to standard comorbidities significantly improved model performance to predict 1-year mortality, long hospital stay, and reduced days at home (Delong p-value < .001). CONCLUSION: Despite significant variation in frailty detection and modest agreement between the two frailty measures, frailty status remained highly predictive of mortality, readmissions, long hospital stay, and reduced days at home among patients undergoing LAAC. Measuring frailty in clinical practice, regardless of the method used, may provide prognostic information useful for patients being considered for LAAC, and may inform shared decision-making in this population.


Asunto(s)
Apéndice Atrial , Fibrilación Atrial , Procedimientos Quirúrgicos Cardíacos , Fragilidad , Accidente Cerebrovascular , Humanos , Anciano , Estados Unidos/epidemiología , Recién Nacido , Apéndice Atrial/cirugía , Medicare , Procedimientos Quirúrgicos Cardíacos/métodos , Comorbilidad , Fibrilación Atrial/complicaciones , Accidente Cerebrovascular/etiología
11.
BMC Surg ; 23(1): 330, 2023 Oct 27.
Artículo en Inglés | MEDLINE | ID: mdl-37891506

RESUMEN

BACKGROUND: Both video-assisted thoracoscopic surgery (VATS) thymectomy and robot-assisted thoracoscopic surgery (RATS) thymectomy have been suggested as technically sound approaches for early-stage thymic epithelial tumors. However, the choice of VATS or RATS thymectomy for large and advanced thymic epithelial tumors remains controversial. In this study, the perioperative outcomes of VATS and RATS thymectomy were compared in patients with large thymic epithelial tumors (size ≥5.0 cm). METHODS: A total of 113 patients with large thymic epithelial tumors who underwent minimally invasive surgery were included. Sixty-three patients underwent RATS, and 50 patients underwent VATS. Patient characteristics and perioperative variables were compared. RESULTS: Compared with the VATS group, the RATS group experienced a shorter operation time (median: 110 min vs.130 min; P < 0.001) and less blood loss (30.00 ml vs. 100.00 ml, P < 0.001). No patients in the RATS group needed conversion to open surgery, but in the VATS series, five patients required conversion to open procedures (0% vs. 14.29%, P = 0.054). The rate of concomitant resection in the RATS group was similar to that in the VATS group (11.43% vs. 5.71%; P = 0.673). There was no significant difference between the two groups in the duration of chest tube (P = 0.587), postoperative complications (P = 1.000), and the duration of postoperative hospital stay (P = 0.141). CONCLUSION: For large thymic epithelial tumors, RATS thymectomy can be performed safely and effectively in a radical fashion. Due to the advanced optics and precise instrument control, concomitant resections can be easily achieved in larger thymic epithelial tumors using the robotic approach.


Asunto(s)
Neoplasias Glandulares y Epiteliales , Robótica , Neoplasias del Timo , Humanos , Timectomía/métodos , Cirugía Torácica Asistida por Video/métodos , Estudios Retrospectivos , Neoplasias del Timo/cirugía , Neoplasias del Timo/patología , Neoplasias Glandulares y Epiteliales/cirugía
12.
Angew Chem Int Ed Engl ; 62(33): e202303075, 2023 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-37202371

RESUMEN

A highly enantioselective catalytic system for exo-Diels-Alder reactions was developed based on the newly discovered bispyrrolidine diboronates (BPDB). Activated by various Lewis or Brønsted acids, BPDB can catalyze highly stereoselective asymmetric exo-Diels-Alder reactions of monocarbonyl-based dienophiles. When 1,2-dicarbonyl-based dienophiles are used, the catalyst can sterically distinguish between the two binding sites, which leads to highly regioselective asymmetric Diels-Alder reactions. BPDB can be prepared as crystalline solids on a large scale and are stable under ambient condition. Single-crystal X-ray analysis of the structure for acid-activated BPDB indicated that its activation involves cleavage of a labile B←N bond.

13.
J Am Chem Soc ; 144(47): 21800-21807, 2022 11 30.
Artículo en Inglés | MEDLINE | ID: mdl-36383694

RESUMEN

Palladium-catalyzed carbonylation reactions are efficient methods for synthesizing valuable molecules. However, realizing a carbonylation with excellent yield and chemo-, regio-, and enantioselectivities by classical low-valent palladium catalysis is highly challenging. Herein, we describe an enantioselective carbonylation reaction using a high-valent palladium catalysis strategy and employing a chiral sulfoxide phosphine (SOP) ligand. This double aminocarbonylation reaction begins with the formation of a carbamoylpalladium(II) species, which undergoes enantioselective oxidative addition with a cyclic diaryliodonium salt to generate a palladium(IV) intermediate, followed by a second CO insertion and reductive elimination. The mechanism has been illustrated with experimental and computational studies.


Asunto(s)
Paladio , Sulfóxidos , Estereoisomerismo , Catálisis , Ligandos
14.
Cancer ; 128(4): 708-718, 2022 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-35076939

RESUMEN

BACKGROUND: Circulating tumor DNA (ctDNA) has emerged as a noninvasive biomarker for dynamically monitoring tumors. However, published data on perioperative ctDNA in patients with operable non-small cell lung cancer (NSCLC) are currently limited. METHODS: This prospective study recruited 123 patients with resectable stage I to IIIA NSCLC. Preoperative and postoperative plasma samples and tumor tissue samples were subjected to next-generation sequencing with a panel of 425 cancer-related genes. Peripheral blood samples were collected before surgery, postoperatively within 1 month, and every 3 to 6 months for up to 3 years. RESULTS: After 4 exclusions, 119 eligible patients were enrolled from June 2016 to February 2019. Presurgical ctDNA was detectable in 29 of 117 patients (24.8%) and was associated with inferior recurrence-free survival (RFS; hazard ratio [HR], 2.42; 95% CI, 1.11-5.27; P = .022) and inferior overall survival (OS; HR, 5.54; 95% CI, 1.01-30.35; P = .026). Similarly, ctDNA was detected in 12 of 116 first postsurgical samples (10.3%) and was associated with shorter RFS (HR, 3.04; 95% CI, 1.22-7.58; P = .012). During surveillance after surgery, longitudinal ctDNA-positive patients (37 of 119; 31.1%) had significantly shorter RFS (HR, 3.46; 95% CI, 1.59-7.55; P < .001) and significantly shorter OS (HR, 9.99; 95% CI, 1.17-85.78; P = .010) in comparison with longitudinal ctDNA-negative patients. Serial ctDNA detection preceded radiologic disease recurrence by a median lead time of 8.71 months. CONCLUSIONS: These results suggest that perioperative ctDNA analyses can predict recurrence and survival, and serial ctDNA analyses can identify disease recurrence/metastasis earlier than routine radiologic imaging in patients with resectable NSCLC. LAY SUMMARY: The utility of serial circulating tumor DNA (ctDNA) monitoring for predicting disease recurrence and survival for early-stage non-small cell lung cancer (NSCLC) has not been well characterized. The detection of ctDNA before and after surgery is associated with the identification of a high risk of disease recurrence and long-term patient outcomes for resectable NSCLC. Perioperative ctDNA analyses identify disease recurrence earlier than routine radiologic imaging. ctDNA analyses can detect minimal residual disease for resectable NSCLC and thus can facilitate early intervention.


Asunto(s)
Biomarcadores de Tumor , Carcinoma de Pulmón de Células no Pequeñas , ADN Tumoral Circulante , Neoplasias Pulmonares , Biomarcadores de Tumor/sangre , Carcinoma de Pulmón de Células no Pequeñas/sangre , Carcinoma de Pulmón de Células no Pequeñas/cirugía , ADN Tumoral Circulante/sangre , Humanos , Neoplasias Pulmonares/sangre , Neoplasias Pulmonares/cirugía , Recurrencia Local de Neoplasia/sangre , Recurrencia Local de Neoplasia/patología , Pronóstico , Estudios Prospectivos
15.
Opt Express ; 30(7): 10293-10305, 2022 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-35473000

RESUMEN

We proposed and experimentally demonstrated a low loss modified Bezier bend for silicon and silicon nitride photonic integrated circuits. Both simulation and experimental results confirm that the modified Bezier bend can effectively reduce the bend loss for silicon and silicon nitride platform. At a bend radius of 1 µm, the reduction of bend loss from 0.367 dB/90° of circular bend and 0.35 dB/90° of traditional Bezier bend to 0.117 dB/90° of modified Bezier bend for silicon platform was experimentally demonstrated. For a 12-µm radius silicon nitride bend, the bend loss reduction from 0.65 dB/90° of circular bend and 0.575 dB/90° of traditional Bezier bend to 0.32 dB/90° was achieved. The proposed modified Bezier bend design can also be applied to other material systems, such as InP, LN, GaAs, etc., to effectively reduce the bend waveguide loss.

16.
Stat Med ; 41(18): 3449-3465, 2022 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-35673849

RESUMEN

Routinely-collected health data can be employed to emulate a target trial when randomized trial data are not available. Patients within provider-based clusters likely exert and share influence on each other's treatment preferences and subsequent health outcomes and this is known as dissemination or spillover. Extending a framework to replicate an idealized two-stage randomized trial using routinely-collected health data, an evaluation of disseminated effects within provider-based clusters is possible. In this article, we propose a novel application of causal inference methods for dissemination to retrospective cohort studies in administrative claims data and evaluate the impact of the normality of the random effects distribution for the cluster-level propensity score on estimation of the causal parameters. An extensive simulation study was conducted to study the robustness of the methods under different distributions of the random effects. We applied these methods to evaluate baseline prescription for medications for opioid use disorder among a cohort of patients diagnosed with opioid use disorder and adjust for baseline confounders using information obtained from an administrative claims database. We discuss future research directions in this setting to better address unmeasured confounding in the presence of disseminated effects.


Asunto(s)
Trastornos Relacionados con Opioides , Causalidad , Estudios de Cohortes , Bases de Datos Factuales , Humanos , Trastornos Relacionados con Opioides/diagnóstico , Trastornos Relacionados con Opioides/tratamiento farmacológico , Trastornos Relacionados con Opioides/epidemiología , Estudios Retrospectivos
17.
J Org Chem ; 87(16): 10958-10966, 2022 08 19.
Artículo en Inglés | MEDLINE | ID: mdl-35901268

RESUMEN

Controlling the number of C-H bond activation is a long-standing challenge in organic synthesis. Recently, Yu's group demonstrated that in Pd-catalyzed alanine's arylation, pyridine-type ligands favor a mono-C-H bond activation, while quinoline-type ligands favor a di-C-H bond activation. To disclose the underlying principles, a theoretical study (density functional theory (DFT)) has been carried out. Our study indicates that a mono-ligand model, which is generally adopted in the community, does not reproduce the experimentally observed mono-/di-selectivity, while a bi-ligand model can rationalize the experimental observations well, including the observed diastereoselectivity in diarylation. The electron-rich pyridine-type ligands with less steric congestion can promote the C-H bond activation reaction of alanine derivatives. The quinoline-type ligands have a better π back-donation interaction with the metal, which makes a more active C-H bond activation than the pyridine-type ligands for this reaction. This bi-ligand model, which is a necessity, allows the understanding and future design of a dual ligand effect in C-H bond activation.


Asunto(s)
Paladio , Quinolinas , Alanina , Catálisis , Ligandos , Paladio/química , Piridinas
18.
Crit Care ; 26(1): 252, 2022 08 22.
Artículo en Inglés | MEDLINE | ID: mdl-35996150

RESUMEN

Pulmonary microbial diversity may be influenced by biotic or abiotic conditions (e.g., disease, smoking, invasive mechanical ventilation (MV), etc.). Specially, invasive MV may trigger structural and physiological changes in both tissue and microbiota of lung, due to gastric and oral microaspiration, altered body posture, high O2 inhalation-induced O2 toxicity in hypoxemic patients, impaired airway clearance and ventilator-induced lung injury (VILI), which in turn reduce the diversity of the pulmonary microbiota and may ultimately lead to poor prognosis. Furthermore, changes in (local) O2 concentration can reduce the diversity of the pulmonary microbiota by affecting the local immune microenvironment of lung. In conclusion, systematic literature studies have found that invasive MV reduces pulmonary microbiota diversity, and future rational regulation of pulmonary microbiota diversity by existing or novel clinical tools (e.g., lung probiotics, drugs) may improve the prognosis of invasive MV treatment and lead to more effective treatment of lung diseases with precision.


Asunto(s)
Pulmón , Microbiota , Respiración Artificial , Humanos , Pulmón/microbiología , Respiración Artificial/efectos adversos , Lesión Pulmonar Inducida por Ventilación Mecánica/epidemiología
19.
Appl Opt ; 61(1): 84-90, 2022 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-35200809

RESUMEN

Single-mode lasing for small size semiconductor laser is significantly important in the on-chip optical signal processing, data storage, and dense optical integrated systems. This paper presents new, to the best of our knowledge, single-mode quantum well microlasers by distributing periodical strain along the longitudinal laser cavity. The quantum transmission line modeling (Q-TLM) method is employed to establish the model for strained microlasers. The dynamic output of quantum well microlasers with longitudinal periodical strain (LPS) distribution is analyzed in the time and frequency domains, and it is found that the introduction of LPS significantly improves the single-mode output of quantum well microlasers by increasing the side mode suppression ratio (SMSR) from 8.44 to 28.29 dB. The study results confirm that well-controlled periodical strain along the longitudinal laser cavity provides an alternative routine for realizing single-mode lasing by strain engineering.

20.
Oral Dis ; 28(8): 2139-2148, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-33772986

RESUMEN

Treatment of oral squamous cell carcinoma remains a challenge due to a high incidence of treatment resistance, which is followed by tumor recrudescence and metastasis to the lymph nodes. Thus, it is important to explore novel inhibitors of OSCC. Here, we aimed to identify drugs that may cooperate with histone deacetylase inhibitors to reverse the EMT, inhibit EMT and cell migration and invasion, and contribute to therapeutic efficacy. We found that treatment with 4sc-202 potently reversed the EMT and thereby inhibited cell migration and invasion in vitro, in part by inducing expression of the FoxO1 tumor-suppressor gene. Furthermore, 4sc-202 also synergized with Ink-128 to inhibit tumor migration and invasion in vitro. Mechanistically, 4sc-202 induced FoxO1 expression, whereas Ink-128 promoted nuclear translocation of FoxO1. Our findings indicated that FoxO1 might reverse the EMT by interacting with Twist1 in OSCC. In conclusion, we identified an effective combination therapy involving class I histone deacetylase and mammalian target of rapamycin complex 1/2 inhibition that effectively blocked the EMT of tumor cells by upregulating FoxO1 expression to inhibit Twist1 transcription. These data have implications for developing new targets for early diagnosis and treatment of OSCC.


Asunto(s)
Carcinoma de Células Escamosas , Neoplasias de Cabeza y Cuello , Neoplasias de la Boca , Benzamidas/farmacología , Benzamidas/uso terapéutico , Carcinoma de Células Escamosas/patología , Línea Celular Tumoral , Movimiento Celular/genética , Transición Epitelial-Mesenquimal/genética , Inhibidores de Histona Desacetilasas/farmacología , Inhibidores de Histona Desacetilasas/uso terapéutico , Histona Desacetilasas/uso terapéutico , Humanos , Tinta , Neoplasias de la Boca/patología , Recurrencia Local de Neoplasia , Serina-Treonina Quinasas TOR
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