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Tyrosyllysylthreonine (YKT) is a peptide structure that contains three different amino acids in its structure and has anticancer properties. The main purpose of this study is to reveal the structural interactions of the peptide and to increase the efficiency of the peptide with nanoformulation. For these purposes, YKT-loaded poly(ε-caprolactone) (PCL) nanoparticles (NPs) were synthesized using the double-emission precipitation method and the obtained NPs were characterized with a Zeta Sizer, UV-Vis, Fourier transform infrared-attenuated total reflection spectrometers, scanning electron microscopy, and transmission electron microscopy. The in vitro release profile of the peptide-loaded PCL NPs was determined. In molecular modeling studies, PCL, PCL-polyvinyl alcohol (PVA), and PCL-PVA-YKT systems were simulated in an aqueous medium by molecular dynamics simulations, separately. The information about the interactions between the YKT tripeptide and the epidermal growth factor and androgen, estrogen, and progesterone receptors were obtained with the molecular docking study. Additionally, the ADME profile of YKT was determined as a result of each docking study. In conclusion, tripeptide-based nanodrug development studies of the YKT tripeptide are presented in this study.
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Portadores de Fármacos , Nanopartículas , Portadores de Fármacos/química , Sistemas de Liberación de Medicamentos , Simulación del Acoplamiento Molecular , Nanopartículas/química , Péptidos/química , Poliésteres , Polietilenglicoles/química , Relación Estructura-ActividadRESUMEN
The aim of this study was to develop a novel nanosize drug candidate for cancer therapy. For this purpose, (S)-methyl 2-[(7-hydroxy-2-oxo-4-phenyl-2H-chromen-8-yl)methyleneamino]-3-(1H-indol-3-yl)propanoate (ND3) was synthesized by the condensation reaction of 8-formyl-7-hydroxy-4-phenylcoumarin with l-tryptophan methyl ester. Its controlled release formulation was prepared and characterized by different spectroscopic and imaging methods. The cytotoxic effects of ND3 and its controlled release formulation were evaluated against MCF-7 and A549 cancer cell lines, and it was found that both of them have a toxic effect on cancer cells. For drug design and process development, the molecular docking analysis technique helps to clarify the effects of some DNA-targeted anticancer drugs to determine the interaction mechanisms of these drugs on DNA in a shorter time and at a lower cost. By using the molecular docking analysis and DNA binding assays, the interaction between the synthesized compound and DNA was elucidated and non-binding interactions were also determined. To predict the pharmacokinetics, and thereby accelerate drug discovery, the absorption, distribution, metabolism, excretion and toxicity values of the synthesized compound were determined by in silico methods.
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Antineoplásicos/farmacología , Neoplasias de la Mama/tratamiento farmacológico , Cumarinas/farmacología , Diseño de Fármacos , Neoplasias Pulmonares/tratamiento farmacológico , Nanopartículas , Nanotecnología , Células A549 , Antineoplásicos/síntesis química , Antineoplásicos/farmacocinética , Neoplasias de la Mama/patología , Supervivencia Celular/efectos de los fármacos , Cumarinas/síntesis química , Cumarinas/farmacocinética , Preparaciones de Acción Retardada , Femenino , Humanos , Neoplasias Pulmonares/patología , Células MCF-7 , Simulación del Acoplamiento MolecularRESUMEN
OBJECTIVE: Craniopharyngiomas are one of the most challenging problems for neurosurgeons because of the high recurrence rates due to their localization and associated endocrinological disorders. This study reports the outcomes of surgeries and recurrence rates of 45 craniopharyngioma cases. METHOD: Patients who were diagnosed with craniopharyngioma in the authors' clinic between 1998 and 2016 evaluated retrospectively. RESULTS: A total of 45 patients (25 males and 20 females; age, 3-56 years) who had previously undergone surgery for craniopharyngioma were enrolled and followed up for 12 to 222 months (mean follow-up duration, 73.5â±â55.2 months). Among these, 25 were children (55.5%) with a mean age of 9.5â±â4.6 years and 20 were adults (45.5%) with a mean age of 37.2â±â12.7 years. A total of 39 (86.6%) patients underwent total tumor resection, while 6 (13.4%) underwent subtotal tumor removal. During 12 to 30 months of follow-up, the progression of residual tumor was recorded in 4 patients, 3 of whom underwent surgery and postoperative radiotherapy. Despite the total resection of tumor in their first surgery, 3 patients showed tumor recurrence during 15 to 34 months of the follow-up. CONCLUSION: Our findings suggest that the total resection of craniopharyngiomas, when possible, results in a favorable quality of life, with acceptable mortality and morbidity rates.
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Craneofaringioma , Adolescente , Adulto , Niño , Preescolar , Craneofaringioma/epidemiología , Craneofaringioma/cirugía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Adulto JovenRESUMEN
Background and aim: Malignant middle cerebral artery infarction (MMCAI) usually leads to brain edema that may result in transtentorial herniation and brainstem compression. The prognosis of MMCAI is generally poor. The aim of this study was to discuss our experience with surgical decompression for MMCAI, and determine the association between timing of craniectomy and neurological outcomes. Methods: We identified consecutive patients diagnosed with MMCAI who underwent decompressive craniectomy (DC). Clinical and demographic data were obtained from electronic medical records, including: age, sex, preoperative Glasgow Coma Scale (GCS) score, surgery timing, postoperative GCS scores, and modified Rankin Scale (mRS) scores. Results: This study included 27 stroke patients (aged 38â»80 years) operated within 72 h of the onset of neurological symptoms. Sixteen, five, and six patients underwent DC within 24 h, between 24 and 48 h, and after 48 h after onset of symptoms, respectively. Five patients died after the surgery. Patients who underwent DC within 24 h and 24â»48 h had better mean GCS scores than those who underwent DC after 48 h (p = 0.000, p = 0.015). In addition, patients who underwent DC within 24 h had better mean postoperative mRS scores (p = 0.000) than other patients. Patients older than 60 years had significantly lower GCS scores (p = 0.027) and higher mRS scores (p = 0.033) than younger patients. Conclusion: Our findings support that DC had satisfying outcomes in patients who underwent DC within 24 h. Older age and lower Glasgow Coma Scale scores among DC patients with MMCAI are associated with high morbidity and mortality.
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Craniectomía Descompresiva , Infarto de la Arteria Cerebral Media/cirugía , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Estudios Transversales , Femenino , Escala de Coma de Glasgow , Humanos , Infarto de la Arteria Cerebral Media/diagnóstico por imagen , Infarto de la Arteria Cerebral Media/mortalidad , Masculino , Persona de Mediana Edad , Tomografía Computarizada por Tomografía de Emisión de Positrones , Pronóstico , Estudios Retrospectivos , Factores de Tiempo , Resultado del TratamientoRESUMEN
AIM: To clarify whether unmasking of central sleep apnea during continuous positive airway pressure (CPAP) initiation can be identified from initial diagnostic polysomnography (PSG) in patients with heart failure with reduced ejection fraction (HFREF) and obstructive sleep apnea (OSA) MATERIALS AND METHODS: Forty-three consecutive patients with obstructive sleep apnea and central sleep apnea (OSA/CSA) in HFREF were matched with 43 HFREF patients with OSA and successful CPAP initiation. Obstructive apneas during diagnostic PSG were then analyzed for cycle length (CL), ventilation length (VL), apnea length (AL), time to peak ventilation (TTPV), and circulatory delay (CD). We calculated duty ratio (DR) as the ratio of VL/CL and mathematic loop gain (LG). RESULTS: While AL was similar, CL, VL, TTPV, CD, and DR was significantly longer in patients with OSA/CSA compared to those with OSA, and LG was significantly higher. Receiver operator curves identified optimal cutoff values of 50.2 s for CL (area under the curve (AUC) 0.85, 29.2 s for VL (AUC 0.92), 11.5 s for TTPV (AUC 0.82), 26.4 s for CD (AUC 0.79), and 3.96 (AUC 0.78)) respectively for LG to identify OSA/CSA. CONCLUSION: OSA/CSA in HFREF can be identified by longer CL, VL, TTPV, and CD from obstructive events in initial diagnostic PSG. The underlying mechanisms seem to be the presence of an increased LG.
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Insuficiencia Cardíaca/fisiopatología , Índice de Severidad de la Enfermedad , Apnea Central del Sueño/fisiopatología , Apnea Obstructiva del Sueño/fisiopatología , Volumen Sistólico , Adulto , Estudios de Casos y Controles , Presión de las Vías Aéreas Positiva Contínua/métodos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Polisomnografía/métodosRESUMEN
Antibodies play an important role in combating and controlling viral diseases such as influenza. Immunoglobulin Y (IgY) antibodies have several advantages such as a less invasive manufacturing process, ease of isolation, higher affinity compared with IgG antibodies, and cost-effectiveness. To date, although specific IgY production has been performed for different strains of influenza A, to the best of our knowledge, an IgY against the M2e peptide has not been produced. In the current study, IgY antibodies are produced, purified, and characterized using the M2e peptide sequence for the first time with the intent to apply them for the diagnosis of influenza A virus. Anti-M2e IgY antibodies are obtained from eggs using a two-step purification method. The activity and characterization of the antibodies are determined using an enzyme-linked immunosorbent assay, a nano-spectrophotometer, an SDS-Page assay, and a Western Blot analysis. Finally, anti-M2e IgY antibodies are conjugated to the latex nanoparticles, and the reaction between the influenza A virus and the nanoparticles is demonstrated using light microscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy. In conclusion, this study shows that anti-M2e IgY antibodies can contribute to the diagnosis, treatment, and prevention of the influenza A virus.
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Anticuerpos Antivirales , Pollos/inmunología , Inmunoglobulinas , Subtipo H1N1 del Virus de la Influenza A , Gripe Aviar/diagnóstico , Nanopartículas/química , Péptidos/inmunología , Proteínas Virales/inmunología , Animales , Anticuerpos Antivirales/química , Anticuerpos Antivirales/inmunología , Especificidad de Anticuerpos , Inmunoglobulinas/química , Inmunoglobulinas/inmunología , Subtipo H1N1 del Virus de la Influenza A/química , Subtipo H1N1 del Virus de la Influenza A/inmunología , Gripe Aviar/inmunología , Péptidos/química , Proteínas Virales/químicaRESUMEN
Graphite intercalation compounds (GICs) have attracted tremendous attention due to their exceptional properties that can be finely tuned by controlling the intercalation species and concentrations. Here, we report for the first time that potassium (K) ions can electrochemically intercalate into graphitic materials, such as graphite and reduced graphene oxide (RGO) at ambient temperature and pressure. Our experiments reveal that graphite can deliver a reversible capacity of 207 mAh/g. Combining experiments with ab initio calculations, we propose a three-step staging process during the intercalation of K ions into graphite: C â KC24 (Stage III) â KC16 (Stage II) â KC8 (Stage I). Moreover, we find that K ions can also intercalate into RGO film with even higher reversible capacity (222 mAh/g). We also show that K ions intercalation can effectively increase the optical transparence of the RGO film from 29.0% to 84.3%. First-principles calculations suggest that this trend is attributed to a decreased absorbance produced by K ions intercalation. Our results open opportunities for novel nonaqueous K-ion based electrochemical battery technologies and optical applications.
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The advancements in the capabilities of artificial sensory technologies, such as electronic/optical noses and tongues, have significantly enhanced their ability to identify complex mixtures of analytes. These improvements are rooted in the evolving manufacturing processes of cross-reactive sensor arrays (CRSAs) and the development of innovative computational methods. The potential applications in early diagnosis, food quality control, environmental monitoring, and more, position CRSAs as an exciting area of research for scientists from diverse backgrounds. Among these, plasmonic CRSAs are particularly noteworthy because they offer enhanced capabilities for remote, fast, and even real-time monitoring, in addition to better portability of instrumentation. Specifically, the synergy between the localized surface plasmon resonance (LSPR) of metallic nanoparticles (NPs) and CRSAs introduces advanced techniques such as LSPR, metal-enhanced fluorescence (MEF), surface-enhanced infrared absorption (SEIRA), surface-enhanced Raman scattering (SERS), and surface-enhanced resonance Raman scattering (SERRS) spectroscopies. This review delves into the importance and versatility of optical-CRSAs, especially those based on plasmonic materials, discussing recent applications and potential new research directions.
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Preservation of paper-based historical artifacts against deterioration due to the presence of bacteria and fungi colonies has been one of the major issues for the importance of protecting the cultural heritage of humankind. Advances in nanotechnology have enabled the implementation of nanomaterials for this purpose. In this work, calcium/chitosan nanoparticles (Ca/CS NPs) were prepared and well-characterized to investigate their potential as a novel approach for preserving paper-based documents. Following the fundamental characterizations, it was found that Ca/CS NPs are spherical nanoparticles with ~65 nm average size and homogenous dispersion (PdI: 0.2). Besides, minimum inhibition concentration results revealed that Ca/CS NPs show a superior antimicrobial effect against specific bacteria and fungi strains commonly found on paper documents compared to the effect of bare chitosan nanoparticles (CS NPs). After the deposition of Ca/CS NPs onto the paper the pH level was increased and stabilized, and only a limited amount of microbial colony formation was observed for up to 20 days. Moreover, molecular docking analysis provided a better insight into the antibacterial and antifungal activities of these nanoparticles. The antimicrobial activity of CS NPs and Ca/CS NPs was investigated through their interactions with E. coli DNA gyrase B and C. albicans dihydrofolate reductase. The binding modes and all possible interactions of active sites were confirmed by in silico molecular docking method. Collectively, our findings revealed that the formulated Ca/CS NPs are promising candidates for preserving paper documents.
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Antiinfecciosos , Quitosano , Nanopartículas , Antibacterianos/farmacología , Antiinfecciosos/farmacología , Calcio/farmacología , Quitosano/química , Quitosano/farmacología , Escherichia coli , Simulación del Acoplamiento Molecular , Nanopartículas/químicaRESUMEN
Rechargeable batteries provide crucial energy storage systems for renewable energy sources, as well as consumer electronics and electrical vehicles. There are a number of important parameters that determine the suitability of electrode materials for battery applications, such as the average voltage and the maximum specific capacity which contribute to the overall energy density. Another important performance criterion for battery electrode materials is their volume change upon charging and discharging, which contributes to determine the cyclability, Coulombic efficiency, and safety of a battery. In this work, we present deep neural network regression machine learning models (ML), trained on data obtained from the Materials Project database, for predicting average voltages and volume change upon charging and discharging of electrode materials for metal-ion batteries. Our models exhibit good performance as measured by the average mean absolute error obtained from a 10-fold cross-validation, as well as on independent test sets. We further assess the robustness of our ML models by investigating their screening potential beyond the training database. We produce Na-ion electrodes by systematically replacing Li-ions in the original database by Na-ions and, then, selecting a set of 22 electrodes that exhibit a good performance in energy density, as well as small volume variations upon charging and discharging, as predicted by the machine learning model. The ML predictions for these materials are then compared to quantum-mechanics based calculations. Our results reaffirm the significant role of machine learning techniques in the exploration of materials for battery applications.
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OBJECTIVES: Intradiscal ozone treatment is a minimally-invasive method that can be applied to patients who have low back pain and do not respond to conservative treatment. This retrospectively designed study aimed to evaluate its clinical efficacy, adverse effects, or complication rates. METHODS: Patients with lumbar degenerative disc disease (LDDD) who underwent intradiscal O2-O3 treatment between January 2016 and April 2018 were included in the study. Pain and disability levels were assessed at pre-injection, 1-month and 1-year post-injection periods using visual analog scale (VAS) and Oswestry Disability Index (ODI), respectively. RESULTS: A total of 520 patients (270 males and 250 females) with the mean age of 38.9±5.7 years included in the study. First-month and 1st-year post-injection VAS and ODI scores were significantly lower than pre-injection scores (p<0.001). Remarkable VAS score reduction (more than 50%) was found in 60.2% of patients at 1st month and in 52.9% of patients at the 1st year. No important side effects recorded. CONCLUSION: Intradiscal ozone therapy applied together with the epidural steroid treatment, one of the percutaneous application techniques for the treatment of low back pain related to LDDD, has successful outcomes, clinical efficacy, and low rate of side effects, and thus, is one of the methods that should be considered before surgery when appropriate patients.
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BACKGROUND: The diagnosis of conjunctival lymphoid tu-mors is straightforward when they present with a characteristic salmon-pink, pebbly, multinodular appearance. However, rarely a diffuse clinical presentation is encountered, and this may mimic chronic conjunctivitis of other etiologies. CASE REPORT: A 60-year-old man was referred to our clinic with bilateral conjunctival masses in May 2005. With the assumption of chlamydial conjunctivitis, without microbiological or histopathological evidence, tetracycline ointment and oral doxycycline 100 mg twice daily were prescribed. Although a partial response was achieved, 2 months after the treatment, the patient's complaints returned. On second referral to our clinic in March 2006, the patient was re-evaluated. He presented with bilateral conjunctival masses resembling conjunctival lymphoma, and a bilateral diagnostic biopsy was performed. Histopathological evaluation of the biopsy specimens revealed mucosa-associated lymphoid tissue (MALT) lymphoma. The patient received CVP chemotherapy (cyclophosphamide, vincristine, prednisolone). After 6 courses of chemotherapy, he achieved partial remission in both eyes. Currently, 28 months after CVP, sustained remission is obtained. CONCLUSIONS: In these cases, a high index of suspicion is required if one is to avoid a delay in diagnosis, and the importance of correct early diagnosis is obvious.
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Neoplasias de la Conjuntiva/diagnóstico , Conjuntivitis de Inclusión/diagnóstico , Linfoma de Células B de la Zona Marginal/diagnóstico , Neoplasias Primarias Múltiples/diagnóstico , Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Biopsia , Enfermedad Crónica , Conjuntiva/patología , Neoplasias de la Conjuntiva/tratamiento farmacológico , Neoplasias de la Conjuntiva/patología , Ciclofosfamida/administración & dosificación , Diagnóstico Diferencial , Estudios de Seguimiento , Humanos , Linfoma de Células B de la Zona Marginal/tratamiento farmacológico , Linfoma de Células B de la Zona Marginal/patología , Masculino , Persona de Mediana Edad , Neoplasias Primarias Múltiples/tratamiento farmacológico , Neoplasias Primarias Múltiples/patología , Prednisona/administración & dosificación , Inducción de Remisión , Vincristina/administración & dosificaciónRESUMEN
Epilobium is a medicinal plant; its extracts are widely used traditional medicine due to their broad range of pharmacological and therapeutic properties. Its most prominent feature is its therapeutic effects on prostatic diseases. The aim of this study is preparation of controlled release system of Epilobium parviflorum, and determination of its potential of anticancer applications. For this purpose, Epilobium parviflorum extract (EPE) loaded chitosan nanoparticles were prepared with ionic gelation method to increase the bioavailability of the extract. The nanoparticles were investigated in terms of size, zeta potential, polydispersity index, encapsulation efficiency, loading capacity and release profile. Besides, scanning electron microscopy (SEM) was used to observe the morphology of the nanoparticles. Moreover, Ames/Salmonella test was used to determine the mutagenicity of EPE, and it was shown that it had no mutagenic effect. It was found that EPE loaded chitosan nanoparticles were with 64.47 nm in average size, 0.168 PdI and 15.2 mV zeta potential. Encapsulation efficiency and loading capacity were found as 92.46% and 8%, respectively. Finally, DNA binding assay and in silico molecular docking studies were performed between EPE and DNA in order to contribute to design of plant based controlled release system for use in cancer therapy.
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Quitosano/química , Epilobium/química , Nanopartículas/química , Disponibilidad Biológica , Portadores de Fármacos/química , Simulación del Acoplamiento Molecular/métodos , Tamaño de la Partícula , Agua/químicaRESUMEN
BACKGROUND: Despite rapid diagnosis and aggressive neurosurgical intervention, acute subdural hematoma (ASDH) is a severe type of head injury that can result in high morbidity and mortality. Although surgical procedures, such as craniotomy and decompressive craniectomy (DC), can be effective, the preferred approach for treating an ASDH remains controversial. The aim of this report was to evaluate factors associated with mortality in patients with ASDH and determinants of outcome in those with ASDH who underwent DC. METHODS: The demographic details and clinical and radiological characteristics of a total of 93 patients with ASDH who underwent DC during a 60-month period from 2012 to 2017 were evaluated to determine the effect on mortality and any association with the Glasgow Coma Scale (GCS) score recorded on arrival. RESULTS: Sixty-five male and 28 female subjects with a mean age of 59.82+-19.49 years (range: 16-88 years) were included in the study. Sixteen patients (17.2%) died following the surgery. Older age (p=0.007) and lower GCS scores (p=0.022) were statistically significantly associated with the mortality rate. The mean hematoma thickness was 15.46+-5.73 mm, and the mean midline shift was 9.90+-4.84 mm. The mortality rate was positively correlated with an excessive midline shift (p=0.011; r=0.262) and age (p=0.022; r=0.237) in patients with ADSH. A midline shift of ≥10 mm and a hematoma thickness of ≥15 mm was significantly associated with mortality (p=0.014; p=0.039). The etiology of the trauma; comorbidities of subarachnoid, epidural, or intracranial hemorrhage; compression fractures; or contusions were not significantly correlated. CONCLUSION: The results indicated that there was a higher mortality rate among older patients and those with a GCS score of <6 on arrival. A midline shift of ≥10 mm and a hematoma thickness of ≥15 mm were significantly related to mortality. Our study supports the conclusion that DC may help prevent further midline shift and be associated with a lower mortality rate compared with a craniotomy.
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Craniectomía Descompresiva/mortalidad , Hematoma Subdural Agudo , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Hematoma Subdural Agudo/epidemiología , Hematoma Subdural Agudo/mortalidad , Hematoma Subdural Agudo/cirugía , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Adulto JovenRESUMEN
OBJECTIVES: In this study, we aimed to share the surgical approaches and clinical experiences of cranio-orbital tumors, which are surgically difficult anatomies. METHODS: A total of 22 orbital tumors with extraorbital-transcranial pathology between January 2004 and December 2017 were retrospectively reviewed. Information was obtained from hospital, operation and outpatient records for this study. Preoperative demographic data, ophthalmologic examination findings, clinical and radiological findings were recorded. All patients had cranial magnetic resonance and cranial computerised tomography examinations at this time. The location of the tumor, its size and its relation to neighboring structures were recorded in the light of these examinations. RESULTS: The lateral approach was performed in 12 cases. The lateral approach was performed with frontotemporal craniotomy. Because of the lateral inferior location of the tumor in three of 12 cases, zygoma osteotomy was added to classical osteotomy. In 10 cases, the anterior approach was applied and the frontal craniotomy was found sufficient in seven cases. In three cases subfrontal craniotomy was added to classical craniotomy. CONCLUSION: The findings obtained in this study suggest that high resection rates can be achieved with appropriate surgical intervention in orbital tumors requiring a transcranial surgical approach. The most important factor in surgical planning is the location of the tumor. The size of the tumor and the expectation of the percentage of surgical removal are the other important factors. In our series, it has reached high excision ratio in most cases with low complication rate, good visual field and eye movements results.
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Giant, partially-thrombosed basilar artery (BA) aneurysms are extraordinarily difficult to treat. Due to the high risk of rupture exclusion of these aneurysms from the circulation is imperative. In certain instances, direct clipping is unsuitable, and high-flow bypass and proximal parent vessel clip occlusion is required. We report a case of a recurrent partially-thrombosed giant BA apex aneurysm treated with endovascular stent-coiling through a previous radial artery bypass graft. Following the initial bypass and aneurysm trapping six years prior, the patient was neurologically stable until three months prior to admission when he developed new diplopia and left third nerve palsy. Imaging studies demonstrated interval enlargement of the thrombosed portion of the aneurysm and increased size in the filling portion of the aneurysm. In the present case, the existing radial artery bypass graft between left VA and left PCA permitted successful stent-assisted embolization of the recurrent BA aneurysm. To our knowledge, this is the first published case of endovascular stent-coiling of a BA aneurysm through a radial artery bypass graft. This novel technique can be a useful alternative for endovascular aneurysm treatment in these challenging lesions.
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Arteria Basilar/cirugía , Revascularización Cerebral/métodos , Embolización Terapéutica/métodos , Aneurisma Intracraneal/cirugía , Arteria Radial/cirugía , Arteria Basilar/diagnóstico por imagen , Revascularización Cerebral/instrumentación , Embolización Terapéutica/instrumentación , Humanos , Aneurisma Intracraneal/diagnóstico por imagen , Masculino , Microcirugia , Persona de Mediana Edad , Arteria Radial/diagnóstico por imagen , Stents , Resultado del TratamientoRESUMEN
Optical transparent and electrical conducting materials with broadband transmission are important for many applications in optoelectronic, telecommunications, and military devices. However, studies of broadband transparent conductors and their controlled modulation are scarce. In this study, we report that reversible transmittance modulation has been achieved with sandwiched nanocarbon thin films (containing carbon nanotubes (CNTs) and reduced graphene oxide (rGO)) via electrochemical alkali-ion intercalation/deintercalation. The transmittance modulation covers a broad range from the visible (450 nm) to the infrared (5 µm), which can be achieved only by rGO rather than pristine graphene films. The large broadband transmittance modulation is understood with DFT calculations, which suggest a decrease in interband transitions in the visible range as well as a reduced reflection in the IR range upon intercalation. We find that a larger interlayer distance in few-layer rGO results in a significant increase in transparency in the infrared region of the spectrum, in agreement with experimental results. Furthermore, a reduced plasma frequency in rGO compared to few-layer graphene is also important to understand the experimental results for broadband transparency in rGO. The broadband transmittance modulation of the CNT/rGO/CNT systems can potentially lead to electrochromic and thermal camouflage applications.
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COVID-19/metabolismo , COVID-19/mortalidad , Endotelio Vascular/enzimología , Óxido Nítrico/metabolismo , Envejecimiento , Proteínas de la Nucleocápside de Coronavirus/metabolismo , Femenino , Humanos , Hipertensión/complicaciones , Masculino , Modelos Teóricos , Estrés Oxidativo , Fosfoproteínas/metabolismo , Transducción de SeñalRESUMEN
We have investigated the stability, maximum intercalation capacity, and voltage profile of alkali metal intercalated hexagonal BC3 (MxBC3), for 0 < x ≤ 2 and M = Li, Na, and K. Our calculations, based on dispersion-corrected density functional theory, show that these intercalation compounds are stable with respect to BC3 and their bulk metal counterparts. Moreover, we found that among all MxBC3 considered, the maximum stable capacity corresponds to an x value of 1.5, 1, and 1.5 for Li, Na, and K, respectively. These values are associated with large gravimetric capacities of 572 mA h/g for Na and 858 mA h/g for Li and K. Importantly, we show that metal intercalated hexagonal BC3 has the advantage of a small open-circuit voltage variation of approximately 0.49, 0.12, and 0.16 V for Li, Na, and K, respectively. Our results suggest that BC3 can become a robust alternative to graphitic electrodes in metal ion batteries, thus encouraging further experimental work.