Influence of Reduced Graphene Oxide and Carbon Nanotubes on the Structural, Electrical, and Photoluminescent Properties of Chitosan Films.

Chitosan is a biopolymer with unique properties that have attracted considerable attention in various scientific fields in recent decades. Although chitosan is known for its poor electrical and mechanical properties, there is interest in producing chitosan-based materials reinforced with carbon-based materials to impart exceptional properties such as high electrical conductivity and high Young's modulus. This study describes the synergistic effect of carbon-based materials, such as reduced graphene oxide and carbon nanotubes, in improving the electrical, optical, and mechanical properties of chitosan-based films. Our findings demonstrate that the incorporation of reduced graphene oxide influences the crystallinity of chitosan, which considerably impacts the mechanical properties of the films. However, the incorporation of a reduced graphene oxide-carbon nanotube complex not only significantly improves the mechanical properties but also significantly improves the optical and electrical properties, as was demonstrated from the photoluminescence studies and resistivity measurements employing the four-probe technique. This is a promising prospect for the synthesis of new materials, such as biopolymer films, with potential applications in optical, electrical, and biomedical bioengineering applications.

Can clinicopathological factors improve the prediction of metastasis to nonsentinel lymph nodes in patients with breast cancer?

INTRODUCTION: To determine whether clinicopathological characteristics can improve the prediction of metastasis to nonsentinel lymph nodes (NSLNs) over the use of only mRNA copy number in sentinel lymph node (SLN) biopsies. METHODS: This was a retrospective, observational study that included a total of 824 patients with T1-3 breast cancer who had clinically negative, ultrasound-negative axilla without evidence of metastasis and who underwent one-step nucleic acid amplification in SLN biopsies. RESULTS: 118 required a complete axillary lymph node dissection (ALNhD). About 35.6% (42/118) had metastases to a NSLN, and 64.4% (76/118) had no metastasis to a NSLN. The ROC curve of the total tumor load (TTL) presented an area under the curve (AUC) of 0.651 (95%; CI: 0.552-0.751). The 7294 copies of CK19 mRNA were established as the optimal cutoff point, with sensitivity: 93%, specificity: 63%, positive predictive value: 44%, and negative predictive value: 91%. By associating the clinicopathological parameters (multicentricity, pooled immunohistochemistry [IHC], and progesterone receptors), the AUC went up to 0.752 (95% CI: 0.663-0.841). CONCLUSIONS: Clinicopathological factors should be considered together with the total CK19 mRNA copy number (the TTL) of the SLNs to improve the predictive capacity of metastatic involvement of the NSLNs.

INTRODUCCIÓN: Nuestro objetivo era determinar si la influencia de las características clínicopatológicas pueden mejorar la predicción de metástasis en los ganglios linfáticos no centinelas (GLNC) a partir de un punto de corte de copias de ARNm determinado en la biopsia del ganglio linfático centinela (GLC). MÉTODOS: Se realizó un estudio observacional retrospectivo incluyendo a un total de 824 pacientes con cáncer de mama T1-3, con axila clínica y ecográficamente negativa para metástasis en los ganglios axilares. Se les practicó una biopsia selectiva del GLC y estudio posterior mediante el método one step nucleic acid amplification (OSNA). RESULTADOS: 118 precisaron una disección completa de los ganglios linfáticos axilares. 35,6% (42/118) tuvieron metástasis en GLNC y 64.4% (76/118) no presentaron metástasis en GLNC. La curva ROC del log de la carga tumoral total (CTT) presentó un área bajo la curva de 0.651 (95%; IC: 0.552-0.751). Se estableció las 7294 copias de ARNm de CK19 como punto de corte óptimo, con sensibilidad: 93%, especificidad: 63%, valor predictivo positivo: 44% y valor predictivo negativo: 91%. Al asociar los parámetros clinicopatológicos (multicentricidad, inmunohistoquímica (IHQ) agrupado y receptores de progesterona) obtenemos un área bajo la curva mejorada de 0.752 (95% intervalo de confianza [IC] 0.663-0.841). CONCLUSIONES: Los factores clinicopatológicos deberían valorarse asociados al corte de copias de ARNm de la CTT de CK19 de los GLCs para mejorar la capacidad predictiva de afectación metastásica en los GLNCs.

Preoperative Vascular Planning of Free Flaps: Comparative Study of Computed Tomographic Angiography, Color Doppler Ultrasonography, and Hand-Held Doppler.

BACKGROUND: Preoperative planning of microsurgical perforator free flaps continues to be a discussion topic among microsurgeons. The purpose of this study was to compare the ability of three methods of preoperative vascular mapping-hand-held Doppler imaging, color Doppler ultrasonography, and computed tomographic angiography-to detect perforators and their concordance with surgical findings. METHODS: A prospective study was performed to evaluate the sensitivity, specificity, and accuracy of hand-held Doppler imaging, color Doppler ultrasonography, and computed tomographic angiography to detect free flap perforators. Each patient undergoing a free flap reconstruction was studied preoperatively with the three methods, and the results were compared to the intraoperative findings. RESULTS: Fifty-three patients undergoing autologous tissue reconstruction were included. Most reconstructions (71.7 percent) were performed with anterolateral thigh flaps. The positive predictive value (color Doppler ultrasonography, 100 percent; computed tomographic angiography, 100 percent; hand-held Doppler imaging, 88.6 percent) and negative predictive value (color Doppler ultrasonography, 100 percent; computed tomographic angiography, 94.3 percent; hand-held Doppler imaging, 90.5 percent) rates were significantly different between methods. The high resolution of the color Doppler ultrasonography probe provided a direct vision of the vasculature arborization and efficiently detected vessels with diameters of less than 0.5 mm. The sensitivity, specificity, and accuracy of color Doppler ultrasonography were greater than those of both computed tomographic angiography and hand-held Doppler imaging. There was 100 percent concordance between color Doppler ultrasonography perforators and the surgical findings. CONCLUSIONS: Color Doppler ultrasonography provides a reproducible, harmless, and accurate way to visualize vascular anatomy. It has a high correlation with the surgical findings, signifying advantages over hand-held Doppler and computed tomographic angiography in sensitivity, specificity, and accuracy. CLINICAL QUESTION/LEVEL OF EVIDENCE: Diagnostic, II.