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1.
Immunity ; 49(2): 326-341.e7, 2018 08 21.
Artículo en Inglés | MEDLINE | ID: mdl-30054204

RESUMEN

The maintenance of appropriate arterial tone is critically important for normal physiological arterial function. However, the cellular and molecular mechanisms remain poorly defined. Here, we have shown that in the mouse aorta, resident macrophages prevented arterial stiffness and collagen deposition in the steady state. Using phenotyping, transcriptional profiling, and targeted deletion of Csf1r, we have demonstrated that these macrophages-which are a feature of blood vessels invested with smooth muscle cells (SMCs) in both mouse and human tissues-expressed the hyaluronan (HA) receptor LYVE-l. Furthermore, we have shown they possessed the unique ability to modulate collagen expression in SMCs by matrix metalloproteinase MMP-9-dependent proteolysis through engagement of LYVE-1 with the HA pericellular matrix of SMCs. Our study has unveiled a hitherto unknown homeostatic contribution of arterial LYVE-1+ macrophages through the control of collagen production by SMCs and has identified a function of LYVE-1 in leukocytes.


Asunto(s)
Colágeno/metabolismo , Glicoproteínas/metabolismo , Receptores de Hialuranos/metabolismo , Macrófagos/metabolismo , Músculo Liso Vascular/citología , Miocitos del Músculo Liso/metabolismo , Rigidez Vascular/fisiología , Animales , Aorta/fisiología , Femenino , Glicoproteínas/genética , Humanos , Ácido Hialurónico/metabolismo , Masculino , Metaloproteinasa 9 de la Matriz/metabolismo , Proteínas de Transporte de Membrana , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Receptores de Factor Estimulante de Colonias de Granulocitos y Macrófagos/genética
2.
Chemistry ; 30(15): e202303949, 2024 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-38116910

RESUMEN

Reaction of the 1,2-disilylenes {(DipAr Am)Si}2 (DipAr Am=[(NDip)2 CAr]- , Dip=2,6-diisopropylphenyl, Ar=4-C6 H4 But (Ar') 1 a or Ph 1 b) and two abnormal N-heterocyclic silylenes, (DipAr Am)SiOCSi{(NDip)2 CAr} (Ar=Ar' 3 a or Ph 3 b) with N2 O led to formation of unprecedented examples of uncoordinated silicon analogues of carboxylic acid anhydrides, (DipAr Am)(O=)SiOSi(=O)(DipAr Am) (Ar=Ar' 2 a or Ph 2 b). Both compounds have been fully characterized, and the mechanism of formation of one explored using DFT calculations. Reduction of sila-acid anhydride 2 a with a dimagnesium(I) compound, [{(Mes Nacnac)Mg}2 ] (Mes Nacnac=[(MesNCMe)2 CH]- , Mes=mesityl), led to the one-electron reduction of the anhydride and formation of a magnesium complex of a sila-acid anhydride radical anion [(Mes Nacnac)Mg{(OSi(DipAr' Am)}2 O] 5. A combination of EPR spectroscopic studies and DFT calculations reveal the unpaired electron to largely reside on one of the amidinate ligands of the complex.

3.
J Org Chem ; 89(13): 9405-9419, 2024 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-38865165

RESUMEN

A new method for the preparation of the underrepresented 1,5-dimethyl-6-thioverdazyl radicals has been developed employing Lawesson's reagent (LR). The synthetic route involves the direct thionation of the carbonyl group of the corresponding dialkylbishydrazone followed by cyclization to give the tetrazinanthione verdazyl precursor on a gram scale. Subsequent oxidation yields the 6-thioverdazyl radical. It was determined that thionation of substrates containing electron-withdrawing groups in the ortho- or para-positions was high yielding. In contrast, for the parent phenyl group or substrates bearing weakly electron-donating substituents, thionation efficiency was significantly reduced. This could be overcome by utilizing partial in situ cyclization, which occurs during work up, to generate the tetrazinanthione directly via a one-pot synthesis. Density functional theory suggests that the LR fragment interacts with the carbonyl prior to cycloaddition and subsequent to cycloreversion, leading to the thiocarbonyl. The electronic nature of the radical is characterized with electron paramagnetic resonance as well as the first report of 6-thioverdazyl redox properties.

4.
Neurourol Urodyn ; 43(1): 81-87, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37767698

RESUMEN

OBJECTIVE: To establish a normal reference value of postvoid residual (PVR) urine volume in "healthy" adults. METHODS: Adults were recruited to undergo uroflowmetry and PVR. Those with neurological disorders, malignancy, diabetes, known lower urinary tract dysfunction, and urinary tract infection within the previous 3 months, were excluded from the study. Constipation was defined as Rome IV ≥ 2. RESULTS: Of the 883 adults enrolled in this study, 194 (22.3%) did not complete the questionnaires or perform the uroflowmetry, 103 (11.7%) met ≥1 exclusion criteria and thus were excluded. In addition, 30 and 38 uroflowmetry were excluded due to artifacts and low bladder volume (BV) (<100 mL), respectively. Finally, 515 uroflowmetry and PVR data from adults aged 36-89 (mean: 59.0 ± 9.5) were examined. There was a significant nonlinear relationship between BV and PVR (p < 0.05), with PVR significantly increased when BV was around 528 mL. Women had lower PVR than men (p < 0.05). PVR also increased as the International Prostatic Symptom Score (IPSS) increased. PVR was unaffected by age and functional constipation. A multivariate analysis revealed that BV (p < 0.05) and IPSS (p < 0.05) had significant influence on PVR, but age, gender, and Rome IV score did not. The 90th and 95th percentiles of PVR for men were 73.2 mL (25% of BV) and 102.6 mL (30% of BV), respectively, while for women they were 60.5 mL (21% of BV) and 93.8 mL (27% of BV), respectively. CONCLUSION: Women had lower PVR than men. The 90th percentile or 95th percentile of normal adults' PVR may serve as the upper limit of normal PVR, and readings above this level may necessitate additional evaluation and treatment. Further studies are required to substantiate these recommendations.


Asunto(s)
Retención Urinaria , Infecciones Urinarias , Masculino , Adulto , Humanos , Femenino , Vejiga Urinaria , Urodinámica , Estreñimiento
5.
J Vasc Res ; 60(3): 137-147, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37285812

RESUMEN

N-methyl-D-aspartate (NMDA) receptors were found to be dysfunctional in hypertensive rats. Methyl palmitate (MP) has been shown to diminish the nicotine-induced increase in blood flow in the brainstem. The aim of this study was to determine how MP modulated NMDA-induced increased regional cerebral blood flow (rCBF) in normotensive (WKY), spontaneously hypertensive (SHR), and renovascular hypertensive (RHR) rats. The increase in rCBF after the topical application of experimental drugs was measured using laser Doppler flowmetry. Topical NMDA application induced an MK-801-sensitive increase in rCBF in anesthetized WKY rats, which was inhibited by MP pretreatments. This inhibition was prevented by pretreatment with chelerythrine (a PKC inhibitor). The NMDA-induced increase in rCBF was also inhibited by the PKC activator in a concentration-dependent manner. Neither MP nor MK-801 affected the increase in rCBF induced by the topical application of acetylcholine or sodium nitroprusside. Topical application of MP to the parietal cortex of SHRs, on the other hand, increased basal rCBF slightly but significantly. MP enhanced the NMDA-induced increase in rCBF in SHRs and RHRs. These results suggested that MP had a dual effect on the modulation of rCBF. MP appears to play a significant physiological role in CBF regulation.


Asunto(s)
Hiperemia , Hipertensión , Ratas , Animales , N-Metilaspartato/toxicidad , Ratas Endogámicas WKY , Ratas Endogámicas SHR , Maleato de Dizocilpina/farmacología , Hipertensión/inducido químicamente , Receptores de N-Metil-D-Aspartato/fisiología
6.
Exp Dermatol ; 32(8): 1246-1252, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-36779689

RESUMEN

Generalised pustular psoriasis (GPP) is a rare and severe form of pustular psoriasis. It is defined by persisting or relapsing macroscopically visible sterile primary pustules occurring on non-acral skin and not within psoriasis plaques. Due to its rarity, there is a lack of randomised controlled trials on GPP and its associated gastrointestinal (GI) and liver disorders. In this article, we present a review of the GI and hepatic disorders associated with GPP. GPP is known to be associated with extracutaneous manifestations such as neutrophilic cholangitis. Abnormal liver function tests are reported in up to 90% of patients with GPP upon diagnosis. Less commonly, pancreatitis and gastrointestinal bleeding have been attributed to GPP. While a psoriasis registry with 7.5% prevalence of pustular psoriasis reported an association with viral hepatitis B and C, the true relationship remains to be elucidated as hepatitis B is endemic in Asia where GPP prevalence is higher. Common genetic mutations between GPP and conditions such as hepatocellular carcinoma and inflammatory bowel disease have been identified, explaining their possible associations and providing answers to potential therapeutic options for these conditions. A lack of recognition of these association may result in unnecessary withdrawal of efficacious and definitive drugs for the treatment of GPP. Understanding the characteristics of the associated GI and hepatic disorders will have important implications for targeting the appropriate therapeutics.


Asunto(s)
Psoriasis , Enfermedades Cutáneas Vesiculoampollosas , Humanos , Psoriasis/tratamiento farmacológico , Enfermedad Aguda , Hígado
7.
Chemistry ; 29(23): e202300135, 2023 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-36725683

RESUMEN

The aryl ketones, 9-fluorenone (fluor), 9-xanthenone (xanth) and 9,10-anthraquinone (anth), were reacted with ß-diketiminato dimagnesium(I) compounds, [{(Ar Nacnac)Mg}2 ] (Ar Nacnac=[HC(MeCNAr)2 ]- , Ar=mesityl (Mes) or 2,6-diisopropylphenyl (Dip)). This gave stable magnesium ketyl complexes which are monomeric, [(Ar Nacnac)(DMAP)Mg(fluor⋅)] (Ar=Mes or Dip, DMAP=4-dimethylaminopyridine) and [(Mes Nacnac)Mg(xanth⋅)(xanth)]; dimeric, [{(Mes Nacnac)Mg(µ-fluor⋅)}2 ], or tetrameric, [{(Dip Nacnac)Mg(µ-anth⋅)}4 ]. In contrast, di-2-pyridylketone (OCPy2 ) is doubly reduced with [{(Xyl Nacnac)Mg}2 ] (Xyl=xylyl) to give a diamagnetic alkoxy/amido complex, [{(Xyl Nacnac)Mg}2 (µ-OCPy2 )]. These complexes have been characterized by X-ray crystallography, and in three cases, EPR spectroscopy. Regioselective C-C hetero-coupling reactions between magnesium ketyls and phenanthroline (phen) have yielded the alkoxy compounds, [(Mes Nacnac)Mg(OCR2 -2-phen)] (OCR2 =xanth, OCPh2 or OC(Ph)(2-Me-Ph)). In addition, homo- C-C couplings of the enones, chalcone (chalc) and dibenziylideneactetone (DBA), using magnesium(I) reducing agents, have afforded dimagnesium enolates, [{(Ar Nacnac)(THF)Mg}2 (µ-chalc2 )] (Ar=Mes or Xyl) and [{(Dip Nacnac)(THF)Mg}2 (µ-DBA2 )]. A pinacol coupling reaction between [{(Dip Nacnac)Mg}2 ] and 2-adamantanone (OAd) yielded [{(Dip Nacnac)(OAd)Mg}2 (µ-OAd2 )], presumably via a ketyl intermediate. This study further highlights the utility magnesium(I) compounds have as selective reducing agents in organic transformations.

8.
Virol J ; 20(1): 176, 2023 08 07.
Artículo en Inglés | MEDLINE | ID: mdl-37550752

RESUMEN

SARS-CoV-2 is a zoonotic betacoronavirus that was first reported at the dawn of 2019 in Wuhan, China and has since spread globally, causing an ongoing pandemic. Anthroponotic transmission was reported early, with confirmed infections reported in 26 species to date, including dogs and cats. However, there is a paucity of reports on the transmission of SARS-CoV-2 to companion animals, and thus, we aimed to estimate the seroprevalence of SARS-CoV-2 in dogs and cats in Sarawak, Malaysia. From August 2022 to 2023, we screened plasma samples of 172 companion animals in Sarawak, Malaysia, using a species-independent surrogate virus neutralization test. Our findings revealed the presence of neutralizing antibodies of SARS-CoV-2 in 24.5% (27/110) of dogs and 24.2% (15/62) of cats. To the best of our knowledge, this is the first report of the seroprevalence of SARS-CoV-2 in companion animals in Malaysia. Our findings emphasize the need for pet owners to distance themselves from their pets when unwell, and a strategy must be in place to monitor SARS-CoV-2 in companion animals to assess the potential impact of the virus on companion animals.


Asunto(s)
COVID-19 , Enfermedades de los Gatos , Enfermedades de los Perros , Animales , Gatos , Perros , SARS-CoV-2 , COVID-19/epidemiología , COVID-19/veterinaria , Mascotas , Malasia/epidemiología , Enfermedades de los Gatos/epidemiología , Estudios Seroepidemiológicos , Enfermedades de los Perros/epidemiología
9.
Brain Cogn ; 168: 105970, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-37086556

RESUMEN

Work on multiple-system theories of cognition mostly focused on the systems themselves, while limited work has been devoted to understanding the interactions between systems. Generally, multiple-system theories include a model-based decision system supported by the prefrontal cortex and a model-free decision system supported by the striatum. Here we propose a neurobiological model to describe the interactions between model-based and model-free decision systems in category learning. The proposed model used spiking neurons to simulate activity of the hyperdirect pathway of the basal ganglia. The hyperdirect pathway acts as a gate for the response signal from the model-free system located in the striatum. We propose that the model-free system's response is inhibited when the model-based system is in control of the response. The new model was used to simulate published data from young adults, people with Parkinson's disease, and aged-matched older adults. The simulation results further suggest that system-switching ability may be related to individual differences in executive function. A new behavioral experiment tested this model prediction. The results show that an updating score predicts the ability to switch system in a categorization task. The article concludes with new model predictions and implications of the results for research on system interactions.


Asunto(s)
Aprendizaje , Enfermedad de Parkinson , Adulto Joven , Humanos , Anciano , Aprendizaje/fisiología , Cognición/fisiología , Ganglios Basales/fisiología , Función Ejecutiva/fisiología , Corteza Prefrontal/fisiología
10.
Adv Health Sci Educ Theory Pract ; 28(1): 107-126, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-35904693

RESUMEN

Interpreting radiographic lesions on dental radiographs is a challenging process especially for novice learners, and there is a lack of tools available to support this diagnostic process. This study introduced dental students to two diagnostic aids with contrasting reasoning approaches-ORAD DDx, which uses an analytic, forward reasoning approach, and a Radiographic Atlas, which emphasizes a non-analytic, backward reasoning approach. We compared the effectiveness of ORAD DDx and the Atlas in improving students' diagnostic accuracy and their ability to recall features of radiographic lesions. Participants (99 third-year dental students) were assigned to ORAD DDx, Atlas and Control groups. In the pre-test and post-test, participants provided their diagnosis for eight types of radiographic lesions. All groups also completed a Cued Recall Test. Feedback about ORAD DDx and the Atlas was collected. Results indicated that the Atlas was more effective than ORAD DDx in improving diagnostic accuracy (Estimated marginal mean difference = 1.88 (95% CI 0.30-3.46), p = 0.014, Cohen's d = 0.714). Participants in the Atlas group also outperformed the Control group in the recall of the lesions' radiographic features (Estimated marginal mean difference = 3.42 (95% CI 0.85-5.99), p = 0.005, Cohen's d = 0.793). Students reported that both ORAD DDx and Atlas increased their confidence and decreased the mental effort required to develop differential diagnosis (p ≤ 0.001). This study demonstrates the effectiveness of a non-analytic approach in interpreting dental radiographs among novice learners through the novel use of diagnostic aids.


Asunto(s)
Diclorodifenil Dicloroetileno , Estudiantes de Odontología , Humanos , Señales (Psicología) , Diagnóstico Diferencial , Recuerdo Mental
11.
Int J Mol Sci ; 24(8)2023 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-37108139

RESUMEN

The present study aimed to investigate the acute effects and the mechanism of ketamine on nicotine-induced relaxation of the corpus cavernosum (CC) in mice. This study measured the intra-cavernosal pressure (ICP) of male C57BL/6 mice and the CC muscle activities using an organ bath wire myograph. Various drugs were used to investigate the mechanism of ketamine on nicotine-induced relaxation. Direct ketamine injection into the major pelvic ganglion (MPG) inhibited MPG-induced increases in ICP. D-serine/L-glutamate-induced relaxation of the CC was inhibited by MK-801 (N-methyl-D-aspartate (NMDA) receptor inhibitor), and nicotine-induced relaxation was enhanced by D-serine/L-glutamate. NMDA had no effect on CC relaxation. Nicotine-induced relaxation of the CC was suppressed by mecamylamine (a non-selective nicotinic acetylcholine receptor antagonist), lidocaine, guanethidine (an adrenergic neuronal blocker), Nw-nitro-L-arginine (a non-selective nitric oxide synthase inhibitor), MK-801, and ketamine. This relaxation was almost completely inhibited in CC strips pretreated with 6-hydroxydopamine (a neurotoxic synthetic organic compound). Ketamine inhibited cavernosal nerve neurotransmission via direct action on the ganglion and impaired nicotine-induced CC relaxation. The relaxation of the CC was dependent on the interaction of the sympathetic and parasympathetic nerves, which may be mediated by the NMDA receptor.


Asunto(s)
Ketamina , Nicotina , Masculino , Ratones , Animales , Nicotina/farmacología , Ketamina/farmacología , Ácido Glutámico/farmacología , N-Metilaspartato/farmacología , Maleato de Dizocilpina/farmacología , Ratones Endogámicos C57BL , Pene/inervación , Serina/farmacología , Óxido Nítrico/farmacología
12.
J Infect Dis ; 225(7): 1129-1140, 2022 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-34888688

RESUMEN

BACKGROUND: The magnitude and durability of immune responses to coronavirus disease 2019 (COVID-19) mRNA vaccines remain incompletely characterized in the elderly. METHODS: Anti-spike receptor-binding domain (RBD) antibodies, angiotensin-converting enzyme 2 (ACE2) competition, and virus neutralizing activities were assessed in plasma from 151 health care workers and older adults (range, 24-98 years of age) 1 month following the first vaccine dose, and 1 and 3 months following the second dose. RESULTS: Older adults exhibited significantly weaker responses than younger health care workers for all humoral measures evaluated and at all time points tested, except for ACE2 competition activity after 1 vaccine dose. Moreover, older age remained independently associated with weaker responses even after correction for sociodemographic factors, chronic health condition burden, and vaccine-related variables. By 3 months after the second dose, all humoral responses had declined significantly in all participants, and remained significantly lower among older adults, who also displayed reduced binding antibodies and ACE2 competition activity towards the Delta variant. CONCLUSIONS: Humoral responses to COVID-19 mRNA vaccines are significantly weaker in older adults, and antibody-mediated activities in plasma decline universally over time. Older adults may thus remain at elevated risk of infection despite vaccination.


Asunto(s)
Vacunas contra la COVID-19 , COVID-19 , Anciano , Anticuerpos Neutralizantes , Anticuerpos Antivirales , COVID-19/prevención & control , Humanos , Inmunidad Humoral , Lactante , ARN Mensajero , SARS-CoV-2 , Vacunas Sintéticas , Vacunas de ARNm
13.
J Infect Dis ; 226(6): 983-994, 2022 09 21.
Artículo en Inglés | MEDLINE | ID: mdl-35543278

RESUMEN

BACKGROUND: Third coronavirus disease 2019 (COVID-19) vaccine doses are broadly recommended, but immunogenicity data remain limited, particularly in older adults. METHODS: We measured circulating antibodies against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein receptor-binding domain, ACE2 displacement, and virus neutralization against ancestral and omicron (BA.1) strains from prevaccine up to 1 month following the third dose, in 151 adults aged 24-98 years who received COVID-19 mRNA vaccines. RESULTS: Following 2 vaccine doses, humoral immunity was weaker, less functional, and less durable in older adults, where a higher number of chronic health conditions was a key correlate of weaker responses and poorer durability. One month after the third dose, antibody concentrations and function exceeded post-second-dose levels, and responses in older adults were comparable in magnitude to those in younger adults at this time. Humoral responses against omicron were universally weaker than against the ancestral strain after both the second and third doses. Nevertheless, after 3 doses, anti-omicron responses in older adults reached equivalence to those in younger adults. One month after 3 vaccine doses, the number of chronic health conditions, but not age, was the strongest consistent correlate of weaker humoral responses. CONCLUSIONS: Results underscore the immune benefits of third COVID-19 vaccine doses, particularly in older adults.


Asunto(s)
Vacunas contra la COVID-19 , COVID-19 , Anciano , Enzima Convertidora de Angiotensina 2 , Anticuerpos Neutralizantes , Anticuerpos Antivirales , COVID-19/prevención & control , Humanos , ARN Mensajero , SARS-CoV-2 , Glicoproteína de la Espiga del Coronavirus , Vacunas Sintéticas , Vacunas de ARNm
15.
Clin Exp Ophthalmol ; 50(1): 50-61, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34714583

RESUMEN

BACKGROUND: Prognostic cytological and molecular features of uveal melanoma have been well researched and are essential in management. Samples can be obtained in vivo through fine needle aspirate biopsy, vitrector cutter, forceps or post-enucleation for off-site testing. This study aims to examine cytological and chromosome microarray yields of these samples. METHODS: A retrospective cohort analysis of 119 uveal melanoma biopsies submitted to our laboratory. Samples included those taken in vivo (n = 57) and post-enucleation (n = 62). Patient and tumour features were collected including age, sex, primary tumour location, basal diameter and tumour height. Prognostic outcomes measured include cell morphology, chromosomal status and immunohistochemistry. RESULTS: Post-enucleation biopsies accounted for just over half of our samples (52%). Post-enucleation samples had a more successful genetic yield than in vivo biopsies (77% vs. 50%, p = 0.04) though there was no difference for cytological yields. There was no difference in cytological or microarray yields between instruments. The vitrector biopsy group had the smallest tumour thickness (5 mm vs. 10 mm [fine-needle aspirate biopsy], p = 0.003). There was a strong correlation between monosomy 3, BAP1 aberrancy and epithelioid cell type in post-enucleation samples (Tb  = 0.742, p = 0.005). However, epithelioid morphology was not associated with either monosomy 3 (p = 0.07) or BAP1 aberrancy (p = 0.24) for in vivo biopsies. CONCLUSIONS: All three biopsy instruments provide similar cytological yields as post-enucleation sampling, although post-enucleation samples had a more successful chromosome microarray yield. Epithelioid cytomorphology alone is insufficient for prognostication in in vivo biopsies, immunohistochemistry would be a useful surrogate test.


Asunto(s)
Neoplasias de la Úvea , Biopsia con Aguja Fina , Humanos , Melanoma , Monosomía , Pronóstico , Estudios Retrospectivos , Medición de Riesgo , Neoplasias de la Úvea/diagnóstico , Neoplasias de la Úvea/genética , Neoplasias de la Úvea/metabolismo
16.
Nano Lett ; 21(12): 5167-5172, 2021 06 23.
Artículo en Inglés | MEDLINE | ID: mdl-34096315

RESUMEN

Indium arsenide quantum dots, which typically emit in the near-infrared, have been utilized in various optoelectronics and biomedical applications, such as covert illumination, optical communication, and deep-tissue imaging. While theory predicts that further quantum confinement through size reduction could enable visible light emission, systems with larger optical bandgaps have not been realized. Here, we report a method of preparing highly luminescent, visible-light-emitting In(Zn)As/ZnSe/ZnS QD, using a low-temperature nanocluster synthesis approach. Each QD contains an ultraconfined In(Zn)As nanocluster and fluoresces at tunable wavelengths between 538 and 640 nm with a high photoluminescence quantum efficiency of 58%. We confirm, through DFT and spectroscopic analysis, that the strong confinement effects in the few-atom-wide In(Zn)As nanoclusters are responsible for the significant spectral shift from the near-infrared to the visible region. These findings suggest that broader-than-expected optical tuning may now be achievable in other quantum-confined semiconductor systems, which could lead to a wider scope of functional applications in optoelectronics.


Asunto(s)
Arsenicales , Puntos Cuánticos , Indio , Luminiscencia
17.
J Tissue Viability ; 31(3): 531-536, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35718595

RESUMEN

AIM: To analyze differences in re-epithelization, exudate absorbency, ease and pain on dressing removal between ALLEVYN™ Non-Adhesive and Betaplast™ N. METHODOLOGY: Patients admitted to the general ward undergoing split skin grafting were recruited. Allevyn and Betaplast were applied on the donor site. Exudate absorption was assessed daily using an absorbency grading chart. Dressing change was done on post-operative day five. Ease of dressing removal and pain score using the Wong-Baker Pain Scale was assessed. The percentage of re-epithelization for each dressing was assessed. RESULTS: 30 patients were recruited. There was a statistically significant difference in exudate absorption on post-operative day 3 (z = -2.006, p = 0.045, T = 236) and post-operative day 4 (z = -2.026, p = 0.0143, T = 188), pain score (z = -2.861, p = 0.004, T = 180), ease of removal (z = -2.668, p = 0.008, T = 126) and re-epithelization (z = -2.566, p = 0.009, T = 336) between Betaplast and Allevyn. CONCLUSION: Betaplast may have faster re-epithelization, better exudate absorption, and is easier to remove while minimizing discomfort as compared to Allevyn.


Asunto(s)
Poliuretanos , Trasplante de Piel , Vendajes , Humanos , Dolor , Poliuretanos/uso terapéutico , Estudios Prospectivos , Cicatrización de Heridas
18.
Eur J Dent Educ ; 26(3): 506-515, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34813667

RESUMEN

INTRODUCTION: The COVID-19 pandemic has necessitated an unprecedented shift from face-to-face teaching to e-learning. Previous surveys revealed the negative impact of COVID-19 on dental education and the physical and psychological well-being of dental students. This qualitative study aimed to investigate the perspectives of dental educators towards e-learning during the pandemic and the impact of this experience on their future adoption of e-learning. MATERIALS AND METHODS: Semi-structured interviews with dental educators from the National University of Singapore were conducted over Zoom. Audio recordings were transcribed verbatim and subjected to thematic analysis. Data saturation was reached. Consolidated criteria for reporting qualitative research (COREQ) was followed. RESULTS: Fifteen out of 22 (68%) eligible dental educators were interviewed. Educators had minimal prior e-learning experience. They encountered difficulties in engaging students, assessing students' understanding and adapting their teaching. A practical challenge was to ensure the well-rounded training of competent dentists with adequate patient-interaction skills through e-learning. Self-motivation of the audience, class size, type of teaching and complexity of the material were perceived as factors influencing the suitability of the e-learning format. Educators reported an increased confidence after this emergency e-learning experience. Some considered sustaining or expanding e-learning in their future teaching practice and highlighted the need for continued investment and institutional support, training on the pedagogy of e-learning modalities and curriculum redesign to accommodate blended learning approaches. CONCLUSIONS: Although the shift to e-learning during the COVID-19 pandemic presented a myriad of challenges, dental educators gained experience and confidence which may accelerate the pace of future e-learning adoption and innovation.


Asunto(s)
COVID-19 , Instrucción por Computador , Educación en Odontología , Humanos , Aprendizaje , Pandemias
19.
Angew Chem Int Ed Engl ; 61(21): e202201248, 2022 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-35266609

RESUMEN

An isostructural series of heavy Group 14 E(I) radical anions (Ge, Sn, Pb), stabilized by a bulky xanthene-based diamido ligand are reported. The radical anions were synthesised by the one-electron reduction of their corresponding E(II) precursor complexes with sodium naphthalenide in THF, yielding the radical anions as charge-separated sodium salts. The series of main group radicals have been comprehensively characterized by EPR spectroscopy, X-ray crystallography and DFT analysis, which reveal that in all cases, the spin density of the unpaired electron almost exclusively resides in a p-orbital of π symmetry located on the Group 14 center.

20.
BMC Womens Health ; 21(1): 298, 2021 08 16.
Artículo en Inglés | MEDLINE | ID: mdl-34399742

RESUMEN

BACKGROUND: The formation of a uterine artery pseudoaneurysm is rare and isolated cases have been reported in the existing literature following caesarean sections, curettages and cone biopsies. There has been no report of pseudoaneurysm formation following a loop electrosurgical excision procedure. Vaginal bleeding could potentially be life threatening if this diagnosis is not considered following cervical instrumentation or surgery. Management options range from haemostatic sutures, image-guided embolisation to surgical repair. We report the diagnosis and management of a case of uterine artery pseudoaneurysm after a loop electrosurgical excision procedure. CASE PRESENTATION: A 37-year-old woman was diagnosed with cervical intraepithelial neoplasia grade 3 (CIN3) and underwent a therapeutic loop electrosurgical excision procedure. One month after the procedure, the patient presented to the emergency department with repeated episodes of sudden-onset heavy vaginal bleeding associated with hypotension and syncope. A computed tomography angiogram was performed, which demonstrated a pseudoaneurysm of the right uterine artery. Following the diagnosis, image-guided embolisation was performed successfully. Post-embolisation angiograms showed successful embolisation of the pseudoaneurysm and the patient had no further episodes of bleeding. CONCLUSIONS: Loop electrosurgical excision procedures are generally safe but rarely, can be complicated by the formation of uterine artery pseudoaneurysms. The depth of the loop electrosurgical excision procedure and vascular anatomy should be considered to prevent such complications. A computed tomography angiogram appears to be ideal for diagnosis. Image-guided embolisation is safe and effective as a therapeutic measure, with minimal morbidity.


Asunto(s)
Aneurisma Falso , Neoplasias del Cuello Uterino , Adulto , Aneurisma Falso/diagnóstico por imagen , Aneurisma Falso/etiología , Aneurisma Falso/cirugía , Electrocirugia/efectos adversos , Femenino , Humanos , Embarazo , Arteria Uterina/diagnóstico por imagen , Arteria Uterina/cirugía , Neoplasias del Cuello Uterino/cirugía , Hemorragia Uterina/etiología
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