Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 51
Filtrar
1.
Beilstein J Org Chem ; 20: 672-674, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38590539
5.
Mater Horiz ; 10(11): 5087-5098, 2023 Oct 30.
Artículo en Inglés | MEDLINE | ID: mdl-37681478

RESUMEN

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is a material that has become ubiquitous in the field of organic electronics. It is most commonly used as a hole transport layer (HTL) in optoelectronic devices and can be purchased commercially in various formulations with different properties. Whilst it is a most convenient material to work with, there are stability issues associated with PEDOT:PSS that are detrimental to device stability and these are due to the acidic nature of the PSS component. In this paper, we present a molecular, non-acidic alternative to PEDOT:PSS. The parent structure is composed of a quater(3,4-ethylenedioxythiophene) unit capped either side of the short chain with two pyridine units. This compound, termed (BEDOTPy)2, can be prepared chemically and electrochemically to give doped materials with a choice of counteranions. Further functionalisation via quaternisation at the nitrogen atoms allows for modification of solubility and film-forming properties. The conductivity of the doped samples can reach up to 3.75 S cm-1. The materials are non-acidic and are therefore attractive alternatives to PEDOT:PSS for device applications. We demonstrate an OLED device using the compound (BEDOTPy-EtOH-I)2PF6 as an HTL, and compare the device performance to one made with PEDOT:PSS. Due to the non-acidic nature of the molecular material, the corresponding OLED device does not show a drop in luminance over time, whereas a loss of performance is observed for the device containing PEDOT:PSS over a short period. These results are presented to introduce the parent compound (BEDOTPy)2 as an attractive alternative to PEDOT:PSS, which can be easily modified chemically to provide a plethora of potential compounds with tunable properties.

6.
Adv Mater ; : e2302259, 2023 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-37086184

RESUMEN

The field of synthetic metals is, and remains, highly influential for the development of organic semiconductor materials. Yet, with the passing of time and the rapid development of conjugated materials in recent years, the link between synthetic metals and organic semiconductors is at risk of being forgotten. This review reflects on one of the key concepts developed in synthetic metals - heteroatom interactions. The application of this strategy in recent organic semiconductor materials, small molecules and polymers, is highlighted, with analysis of X-ray crystal structures and comparisons with model systems used to determine the influence of these non-covalent short contacts. The case is made that the wide range of effective heteroatom interactions and the high performance that has been achieved in devices from organic solar cells to transistors is testament to the seeds sown by the synthetic metals research community.

7.
Beilstein J Org Chem ; 18: 944-955, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35965856

RESUMEN

A novel π-conjugated molecule, EtH-T-DI-DTT is reported, which is fused, rigid, and planar, featuring the electron-rich dithieno[3,2-b:2',3'-d]thiophene (DTT) unit in the core of the structure. Adjacent to the electron-donating DTT core, there are indenone units with electron-withdrawing keto groups. To enable solubility in common organic solvents, the fused system is flanked by ethylhexylthiophene groups. The material is a dark, amorphous solid with an onset of absorption at 638 nm in CH2Cl2 solution, which corresponds to an optical gap of 1.94 eV. In films, the absorption onset wavelength is at 701 nm, which corresponds to 1.77 eV. An ionisation energy of 5.5 eV and an electron affinity of 3.3 eV were estimated by cyclic voltammetry measurements. We have applied this new molecule in organic field effect transistors. The material exhibited a p-type mobility up to 1.33 × 10-4 cm2 V-1 s-1.

8.
AME Case Rep ; 6: 4, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35128312

RESUMEN

The coexistence of alpha- and beta-thalassemia is not uncommon and neither is a single thalassemia subtype with a hemochromatosis H63D mutation, however the inheritance of all three diseases together has yet to be reported. We present this rare case of co-inherited alpha-thalassemia minor and beta-thalassemia minor initially misdiagnosed as iron deficiency anemia (IDA) in a reproductive aged female with a heterozygous H63D mutation. In our case report, a 27-year-old, Asian female presented with excessive lethargy and fatigue for the past 10 months. A year ago, she was prescribed Ferrous Sulfate 325 mg daily supplementation due to a suspicion of IDA secondary to a history of heavy menstruations. Although her reports displayed a low mean corpuscular volume (MCV) anemia, the patient declined therapy at that time due to abnormal labs, specifically regarding her urine and liver that subsequently lead to a hemochromatosis, heterozygous H63D diagnosis following genetic testing. Subsequently, the patient's anemia presenting in the setting of normal ferritin, high iron saturation, and elevated A2 fraction was most likely in accordance to carrying the alpha-thalassemia minor, beta-thalassemia minor, and heterozygous H63D gene mutations. Genetic testing further clarified two of the four alpha-globin genes were deleted, alpha3.7 and alpha4.2, consistent with alpha-thalassemia trait and a heterozygous, frameshift mutation of c.27dupG on the hemoglobin subunit beta (HBB) gene associated with beta-thalassemia minor. The initial diagnosis of IDA was inaccurate following the iron studies displaying normal ferritin levels. This is the first report of combined alpha- and beta-thalassemia with a hemochromatosis H63D mutation. Although the clinical presentation of our patient and laboratory values are stable, the course of inheriting all three diseases together is unknown and may inflate the risk of future complications beyond reported studies. Frequent monitorization of hemoglobin and iron studies will be conducted to follow this rare presentation and prevent life-threating iron overload.

9.
Ann Jt ; 7: 26, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-38529128

RESUMEN

Objective: To describe and discuss the purposed mechanism of mesenchymal stem cells (MSCs) and their effect as a potential therapeutic in osteoarthritis (OA). Background: OA is a chronic, degenerative joint disease affecting millions worldwide. Traditional management, including physical therapy, anti-inflammatories, intra-articular injections, and surgical procedures are directed towards symptom control rather than disease modification. In light of a better understanding that low-grade inflammation disrupts articular cartilage homeostasis in OA, application of MSCs as a form of regenerative medicine has emerged with the goal to provide symptomatic relief as well as reverse the articular cartilage damage seen in OA. Methods: PubMed was searched using terms 'osteoarthritis', 'mesenchymal stem cell', 'regenerative medicine', 'chondrocyte', and 'articular cartilage' available from 2006 through May 2021. Conclusions: The use of MSC therapy for articular cartilage regeneration through direct tissue growth, differentiation, and inflammation modulations for the treatment of OA is promising. MSCs migrate to injured sites, inhibit pro-inflammatory pathways, and promote tissue repair by releasing paracrine signals and differentiating into specialized chondrocytes. Multiple clinical trials have displayed a significant improvement in both pain and joint function, inflammatory cell reduction within a joint, and articular cartilage growth as well as patient safety. However, high quality evidence supporting the beneficial role of MSCs is lacking due to the limited number of studies, small populations tested, and the use of various derivatives. Although limited, current evidence suggests MSCs are a potential therapeutic in OA and provides a great foundation for further research.

10.
Nat Nanotechnol ; 16(3): 313-317, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33288949

RESUMEN

To rival the performance of modern integrated circuits, single-molecule devices must be designed to exhibit extremely nonlinear current-voltage (I-V) characteristics1-4. A common approach is to design molecular backbones where destructive quantum interference (QI) between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) produces a nonlinear energy-dependent tunnelling probability near the electrode Fermi energy (EF)5-8. However, tuning such systems is not straightforward, as aligning the frontier orbitals to EF is hard to control9. Here, we instead create a molecular system where constructive QI between the HOMO and LUMO is suppressed and destructive QI between the HOMO and strongly coupled occupied orbitals of opposite phase is enhanced. We use a series of fluorene oligomers containing a central benzothiadiazole10 unit to demonstrate that this strategy can be used to create highly nonlinear single-molecule circuits. Notably, we are able to reproducibly modulate the conductance of a 6-nm molecule by a factor of more than 104.

11.
Chemistry ; 26(44): 9879-9882, 2020 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-32484600

RESUMEN

In this work, self-assembled amino-acid appended perylene bisimides (PBIs) have been studied that when processed into thin films change their resistivity in response to being bent. The PBIs assemble into structures in water and form thin films upon drying. These normally delicate thin films can be tolerant to bending, depending on the aggregates they form. Furthermore, the films then reversibly change their resistivity in response to this mechanical stimulus. This change is proportional to the degree of bending of the film giving them the potential to be used quantitatively to measure mechanical movement, such as in wearable devices.

12.
J Allied Health ; 48(4): 237-247, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31800653

RESUMEN

The practice models, interdisciplinary team functions, intersecting competencies, economies, and settings of contemporary healthcare are all in flux, demanding that educators reconsider traditional health professions clinical education models and partnerships. The Association of Schools Advancing Health Professions (ASAHP) and Allied Health (AH) deans, collectively and individually, must determine the priorities and strategies to advance AH education. This paper offers five recommendations that stem from a review of literature pertaining to current changes in the healthcare sector and higher education that challenge the availability of AH clinical education. Vetted by AH educators and health system representatives, the recommendations subsume proactive strategies that target factors affecting learning in the clinical environment and aim to meet the needs of patients/clients, employers, students, and educators. The recommendations are: 1) Develop meaningful strategic partnerships with healthcare organizations; 2) Assess and integrate interprofessional competencies for efficient and effective interprofessional practice (IPP); 3) Incorporate effective use of healthcare technology into AH education and practice; 4) Advocate within and among healthcare systems, higher education leadership, accreditation and professional organizations, and governmental agencies to foster and support IPP competencies and effective cross-discipline referrals; 5) Drive excellence in clinical education through promotion of research and scholarly activity.


Asunto(s)
Empleos Relacionados con Salud/educación , Educación Profesional/métodos , Comités Consultivos , Educación Profesional/organización & administración , Práctica Clínica Basada en la Evidencia/educación , Humanos , Comunicación Interdisciplinaria , Modelos Educacionales , Grupo de Atención al Paciente
13.
Beilstein J Org Chem ; 14: 2186-2189, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30202470

RESUMEN

A novel methodology towards fabrication of multilayer organic devices, employing electrochemical polymer growth to form PEDOT and PEDTT layers, is successfully demonstrated. Moreover, careful control of the electrochemical conditions allows the degree of doping to be effectively altered for one of the polymer layers. Raman spectroscopy confirmed the formation and doped states of the PEDOT/PEDTT bilayer. The electrochemical deposition of a bilayer containing a de-doped PEDTT layer on top of doped PEDOT is analogous to a solution-processed organic semiconductor layer deposited on top of a PEDOT:PSS layer without the acidic PSS polymer. However, the poor solubility of electrochemically deposited PEDTT (or other electropolymerised potential candidates) raises the possibility of depositing a subsequent layer via solution-processing.

14.
Biomed Sci Instrum ; 54(1): 308-316, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30853730

RESUMEN

The compositional balance and distribution of trace metals/elements in various body tissues are essential key players in tissue and cellular homeostasis. Low Zn levels as well as overexpression of metalothioneins were implicated in the development and progression of various cancers including the prostate. Nonetheless, wider elemental profiles that relate cancer and normal phenotypes with regards to metal homeostasis were not well elucidated in the literature. Moreover, laboratory animals are currently used as accepted models for studying cancer but the level of their representation of actual cancer tissues was not clear. This study is attempting to assess the relevance of animal models currently in use, as surrogates for cancer and establish their relationship to actual normal and cancer tissues from humans. The major focus of this study was to investigate the differential relationship of metal concentrations and profiles in cancer and normal tissues from cadavers of humans and their comparison to established animal models representing organ cancers. The working hypothesis was that elemental/metal concentrations and profiles seen in post mortem will show significant differences between normal and cancer-derived tissues as well as between various tissue types in humans, rats, and dogs. This study also establishes critical elemental/metal profiles that may be relevant in providing correlations with the development of three major cancers. Normal human and tumor tissues of cadaverous lung, breast, and liver used in this study were obtained from US Biomax Company and relevant animal models (Sprague-dawley and Brown Norwegian rats as well as dogs; were obtained from Jackson Laboratories and the Mississippi State Veterinary Laboratory in Pearl, MS), to analyze for elements and test the hypothesis. Tissue samples were prepared using standardized digestion procedures necessary for use with the Inductively Coupled Plasma-Atomic Emission mass Spectrometry (ICP-MS) to determine the concentrations and profiles of 21 elements including Ag, Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Na, Ni, Pb, Sb, Se, Sr, Tl, V, and Zn. Our data supports the notion that metal/elemental homeostasis is essential for normal tissue function and that elemental variations in content, distributions, and ranking are tissue specific as well as carcinoma and species-specific. Analysis of data showed significant variations in elemental content and distribution profiles/ranking between animal models and actual human tissues consistent with the hypothesis. It is concluded that elemental homeostasis is essential for normal tissue function and that shifts in their distribution and content are essential in determining the use of animal models as surrogates for studying cancer. These results are promising and warrant further studies to confirm the relevance of animal models in relation to their use as pre-clinical tools for examining targeted cancer therapeutics.

15.
Biomed Sci Instrum ; 53: 120-127, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29033472

RESUMEN

The paradoxical role of retinoic acid (All Trans Retinoic Acid; ATRA) in the development of allergic and/or inflammatory complications in contrast to a therapeutic modality for lung pathology is not well understood or established in the literature. As well, the role of Citral (inhibitor of retinoid function; a non-toxic chemical that exists in two forms (diethyl; C1 or cis-trans dimethyl; C2), in the reversal of retinoic acid, ovalbumin and allergic mold spore pathophysiology is also not well ascertained under an in vivo setting. Therefore, it is hypothesized that exposure of F344 lung tissues to supra-physiologic levels of retinoic acid, ovalbumin and mold spores individually or in combination with each other will lead to inflammatory tissue pathology and that Citral 1 and 2 will reverse or ameliorate the related pathological damage to lung tissues. Even though ovalbumin and retinoic acid have been previously applied through intra-tracheal route in cancer prevention and immunological research, the objective of this study was to evaluate the histopathological implications of such exposure in vivo. This IACUC approved in vivo study used Fischer 344 rats (n = 80 ; 229 to 273g), which were randomly assigned to controls as well as ovalbumin and mold-sensitized treatment groups (0.80 mg/kg and 1×109 mold spores combined from 4 strains/100 µl intra-tracheal; all others were dosed by intra-peritoneal injection at days 1 and 7 with 80 mg/kg each of ATRA as well as 20 and 50 mg/kg each of Citrals 1 or 2 individually or in combination to represent all four chemicals and mold spores treatments. Positive and negative controls for each treatment were also included in the study. Animals were housed in rat cages at the JSU Research Animal Core Facilities and were placed on a 12:12 light-dark cycle. A standard rodent diet and water access were provided ad libidum. All animals were sacrificed on day 21 and lung tissues were processed for histopathology. Slides were prepared and were digitized for comparison of tissues pathology. Results showed that exposure of the F344 rats to ovalbumin and ATRA showed various levels of lung tissue damage that was ameliorated by Citral 2 in combination. Mold and ATRA exposure caused various levels of lung tissue damage that was reversed by C1 in combination with each other. Taken together, the study showed that there are variable pathologic inflammatory responses from the interaction of ovalbumin, Citrals, mold spores and retinoic acid, and that the addition of Citrals have reversed lung tissue pathologies. These findings warrants further investigation as to the actual role of these interactions in relation to acute/chronic lung disease and the possibility of reversing retinoid-mediated pathologies in the Fisher rat model.

16.
Biomed Sci Instrum ; 53: 320-327, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29033473

RESUMEN

The role of retinoic acid (All Trans Retinoic Acid; ATRA) in the development of hypervitaminosis A pathophysiology is not well understood or established in the literature. As well, the role of Citral (inhibitor of retinoid function; a non-toxic chemical that exists in two forms (diethyl; C1 or cis-trans dimethyl; C2).) in the reversal of pathophysiological implications is also not ascertained under an in vivo setting. Therefore, it is hypothesized that ovalbumin exposure will sensitize the body to supra-physiologic levels of retinoic acid leading to a negative pathophysiological impact and that Citrals 1 and 2 will reverse or ameliorate the related damage to the body's pathophysiology. Even though ovalbumin and retinoic have been previously applied through intra-tracheal route in cancer prevention and immunological research, the objective of this study was to evaluate their interaction as a remedy for hypervitaminosis A. This IACUC approved in vivo study used Fischer 344 rats (n = 80 ;229 to 273g), which were randomly assigned to controls as well as ovalbumin and mold-sensitized treatment groups (0.80 mg/kg and 1X109 mold spores combined from 4 strains/100 µl intra-tracheal; all others were dosed by intra-peritoneal injection at days 1 and 7 with 80 mg/kg each of ATRA as well as 20 and 50 mg/kg each of Citrals 1 or 2 individually or in combination to represent all four chemicals and mold spores treatments.. Positive and negative controls for each treatment were also included in the study. Animals were housed in rat cages at the JSU Research Animal Core Facilities and were placed on a 12:12 light dark cycle. A standard rodent diet and water access were provided ad-libidum. Rat weights were recorded on day 1 and 21, all animals were sacrificed on day 21 and blood was collected and processed for hematological parameters. Results showed that even though C1 and C2 were not toxic individually, their combination at high dosing was lethal. Exposure of ovalbumin-sensitized rats to ATRA showed various levels of weight losses and negative hematological implications that were ameliorated by exposure to Citrals at various combinations with retinoic acid. Taken together, the study showed that there are variable pathophysiological responses from the interaction of ovalbumin, mold spores and retinoic acid and that Citrals were found to be individually effective in reversing health-related pathophysiologies. These findings warrants further investigations as to the actual role of these interactions in relation to acute pathophysiologic health implications and the possibility of reversing hypervitaminosis A-mediated health-related impacts.

17.
Biomed Sci Instrum ; 52: 104-111, 2016 04.
Artículo en Inglés | MEDLINE | ID: mdl-28603320

RESUMEN

The impact of retinoic acid (All Trans Retinoic Acid; ATRA) and Mold spores (MLD) in the development of lung pathology and in vivo tissue remodeling have not been well established in the literature. In addition, the role of citral (inhibitor of retinoid function) in the improvement of lung pathology has not been ascertained in animal studies. Therefore, it is hypothesized that ATRA and Mold (MLD) exposure will sensitize lung tissues leading to lung tissue pathology and that Citrals (C1 and C2) will reverse, ameliorate or improve the associated pathological damage to lung tissues. The study used an IACUC approved between-subject in vivo randomized split plot factorial design (F344 rat model; N=40). Animals were exposed to seven different treatments including untreated control, MLD, ATRA, Citrals (C1 and C2) and their MLD combinations (MLD+ ATRA+ C1, and MLD+ ATRA+ C2) by intra-peritoneal route. Rat weight and blood data were collected on Days 1 and 21, all animals were sacrificed on day 21, and lung tissues were processed for histopathology. Results from weight and blood data (ANOVA and Duncan) as well as from histopathological analyses supported the findings that exposure of F344 rats to MLD combinations with ATRA and Citrals showed various levels of lung tissue damage that were impacted by either C1 or C2 exposure. This promising study showed impressive responses on the interaction of MLD, Citrals, and ATRA as related to their impact on associated lung tissue pathologies.

18.
J Miss Acad Sci ; 60(Suppl 1): 279-283, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26321773

RESUMEN

ß-estradiol is the most potent estrogen of a group of endogenous estrogen steroids which includes estrone and estriol. This steroid hormone is the most potent natural estrogen, produced mainly by the ovary, placenta, and in smaller amounts by the adrenal cortex, and the male testes. Although ß-estradiol protects the renal and cardiovascular systems, the mechanisms involved remain unclear. In this research, we performed the MTT [3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay to evaluate the effect of ß-estradiol on human T-lymphoma (Jurkat) cells upon 24 and 48 hours, respectively. Lipid peroxidation assay was also performed to estimate the levels of malondialdehyde (MDA) production in ß-estradiol-treated cells. The results of MTT assay demonstrated that low, physiological levels of ß-estradiol induce cellular proliferation in Jurkat T-cells. At higher dose of exposure, ß-estradiol decreases the viability of Jurkat T-cells compared to the control cells. Data generated from lipid peroxidation assay resulted in a significant increase (p < 0.05) in MDA production in ß-estradiol treated sample. Upon 48 h of exposure, MDA concentrations in the sample [µM] (mean ±SE, n = 3) compared to untreated control were 4.9 ± 1.7, 8.1 ± 1,6 11.5 ± 2.2, 21.1 ± 2.3, 19.5 ± 1.4, and 21.5 ± 2.6 in 0, 1, 2, 4, 8, and 16 µM ß-estradiol, respectively. In summary, findings from this study demonstrated that high dose of ß-estradiol is cytotoxic to Jurkat T-cells. This cytotoxicity is found to be associated with oxidative stress.

19.
Beilstein J Org Chem ; 11: 1148-54, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26199671

RESUMEN

Two novel tetrathiafulvalene (TTF) containing compounds 1 and 2 have been synthesised via a four-fold Stille coupling between a tetrabromo-dithienoTTF 5 and stannylated thiophene 6 or thiazole 4. The optical and electrochemical properties of compounds 1 and 2 have been measured by UV-vis spectroscopy and cyclic voltammetry and the results compared with density functional theory (DFT) calculations to confirm the observed properties. Organic field effect transistor (OFET) devices fabricated from 1 and 2 demonstrated that the substitution of thiophene units for thiazoles was found to increase the observed charge transport, which is attributed to induced planarity through S-N interactions of adjacent thiazole nitrogen atoms and TTF sulfur atoms and better packing in the bulk.

20.
Biomed Sci Instrum ; 51: 135-42, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25996710

RESUMEN

Demineralized bone matrix protein (DBM) was considered highly effective in stimulating bone healing. The objective of the study was to explore the use of tricalcium phosphate (TCP) delivery system to continuously deliver DBM in an osteoporotic condition and to evaluate changes in bone density and preservation of the spine. Ovariectomized Sprague Dawley rats were divided into three equal groups (n=16 per group). Animals in group I served as control, animals in groups II and III were surgically implanted with either empty (SHAM) or DBM filled TCP implants adjacent to L4/L5. Eight animals from each group were euthanized at 2 and 8 weeks post implantation. Femurs were evaluated for changes in density, and the lumbar spine was evaluated for changes in the endplate. Results of this study revealed (1) TCP implants were capable of delivering DBM for long duration, (2) use of sustained delivery of DBM did not induce untoward effects in the vital organs or in the uterus, fallopian tubes, or vaginal tissues, (3) DBM had no effect on chondrocyte differentiation in the spine, and (4) DBM did not increase bone density in osteoporotic female rats.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...