Cálculo estructural del ala de una aeronave no tripulada

Trabajo Final (IA)--FCEFN-UNC, 2007Desarrolla un análisis estructural del ala de la aeronave no tripulada fabricada con material compuesto. Verifica el comportamiento estructural, a partir de la evaluación del coeficiente de seguridad a primera falla y la carga crítica al pandeo. Se comprueba que estos resultados cumplan con los valores de carga establecidos por normas aeronáuticas. Por otra parte, se calcula de deflexión de la puntera del ala, la cual puede emplearse posteriormente para validar el modelo de análisis con ensayos a escala real

Microfluidics-Based Chromosome Conformation Capture (3C) Technology for Examining Chromatin Organization with a Low Quantity of Cells

Detecting three-dimensional (3D) genome organization in the form of physical interactions between various genomic loci is of great importance for understanding transcriptional regulations and cellular fate. Chromosome Conformation Capture (3C) method is the gold standard for examining chromatin organization, but usually requires a large number of cells (>10⁷). This hinders studies of scarce tissue samples from animals and patients using the method. Here we developed a microfluidics-based approach for examining chromosome conformation by 3C technology. Critical 3C steps, such as digestion and religation of BAC DNA and cross-linked chromatin, were implemented on a microfluidic chip using a low quantity of cells (<10⁴). Using this technology, we analyzed the chromatin looping interactions in the human β-globin. We envision that our method will provide a powerful tool for low-input analysis of chromosome conformation and epigenetic regulations

Data_Sheet_1_Antibiotic resistance spectrums of Escherichia coli and Enterococcus spp. strains against commonly used antimicrobials from commercial meat-rabbit farms in Chengdu City, Southwest China.PDF

Antimicrobial resistance (AMR) is commonly associated with the inappropriate use of antibiotics during meat-rabbit production, posing unpredictable risks to rabbit welfare and public health. However, there is limited research on the epidemiological dynamics of antibiotic resistance among bacteria indicators derived from local healthy meat-rabbits. To bridge the knowledge gap between antibiotic use and AMR distribution, a total of 75 Escherichia coli (E. coli) and 210 Enterococcus spp. strains were successfully recovered from fecal samples of healthy meat-rabbits. The results revealed that diverse AMR phenotypes against seven commonly used antimicrobials, including ampicillin (AMP), amoxicillin-clavulanic acid (A/C), doxycycline (DOX), enrofloxacin (ENR), florfenicol (FFC), gentamicin (GEN), and polymycin B (PMB), were observed among most strains of E. coli and Enterococcus spp. in two rabbit farms, although the distribution pattern of antibiotic resistance between young and adult rabbits was similar. Among them, 66 E. coli strains showed resistance against 6 antimicrobials except for PMB. However, 164 Enterococcus spp. strains only exhibited acquired resistance against DOX and GEN. Notably, the DOX-based AMR phenotypes for E. coli and Enterococcus spp. strains were predominant, indicating the existing environmental stress conferred by DOX exposure. The MICs tests suggested elevated level of antibiotic resistance for resistant bacteria. Unexpectedly, all GEN-resistant Enterococcus spp. strains resistant high-level gentamicin (HLGR). By comparison, the blaTEM, tetA, qnrS and floR were highly detected among 35 multi-resistant E. coli strains, and aac[6']-Ie-aph[2']-Ia genes widely spread among the 40 double-resistant Enterococcus spp. strains. Nevertheless, the presence of ARGs were not concordant with the resistant phenotypes for a portion of resistant bacteria. In conclusion, the distribution of AMR and ARGs are prevalent in healthy meat-rabbits, and the therapeutic antimicrobials use in farming practice may promote the antibiotic resistance transmission among indicator bacteria. Therefore, periodic surveillance of antibiotic resistance in geographic locations and supervisory measures for rational antibiotic use are imperative strategies for combating the rising threats posed by antibiotic resistance, as well as maintaining rabbit welfare and public health.</p

Visualization 2: Silica microwire-based interferometric electric field sensor

Sensor responding waveform to impulse electric field. Originally published in Optics Letters on 15 August 2015 (ol-40-16-3683

Intracellular Tracking of Single Native Molecules with Electroporation-Delivered Quantum Dots

Quantum dots (QDs) have found a wide range of biological applications as fluorophores due to their extraordinary brightness and high photostability that are far superior to those of conventional organic dyes. These traits are particularly appealing for studying cell biology under a cellular autofluorescence background and with a long observation period. However, it remains the most important open challenge to target QDs at <i>native</i> intracellular molecules and organelles in <i>live</i> cells. Endocytosis-based delivery methods lead to QDs encapsulated in vesicles that have their surface biorecognition element hidden from the intracellular environment. The probing of native molecules using QDs has been seriously hindered by the lack of consistent approaches for delivery of QDs with exposed surface groups. In this study, we demonstrate that electroporation (i.e., the application of short electric pulses for cell permeabilization) generates reproducible results for delivering QDs into cells. We show evidence that electroporation-based delivery does not involve endocytosis or vesicle encapsulation of QDs. The amount of QD loading and the resulting cell viability can be adjusted by varying the parameters associated with the electroporation operation. To demonstrate the application of our approach for intracellular targeting, we study single-molecule motility of kinesin in live cells by labeling native kinesins using electroporation-delivered QDs. We envision that electroporation may serve as a simple and universal tool for delivering QDs into cells to label and probe native molecules and organelles

Intracellular Tracking of Single Native Molecules with Electroporation-Delivered Quantum Dots

Quantum dots (QDs) have found a wide range of biological applications as fluorophores due to their extraordinary brightness and high photostability that are far superior to those of conventional organic dyes. These traits are particularly appealing for studying cell biology under a cellular autofluorescence background and with a long observation period. However, it remains the most important open challenge to target QDs at <i>native</i> intracellular molecules and organelles in <i>live</i> cells. Endocytosis-based delivery methods lead to QDs encapsulated in vesicles that have their surface biorecognition element hidden from the intracellular environment. The probing of native molecules using QDs has been seriously hindered by the lack of consistent approaches for delivery of QDs with exposed surface groups. In this study, we demonstrate that electroporation (i.e., the application of short electric pulses for cell permeabilization) generates reproducible results for delivering QDs into cells. We show evidence that electroporation-based delivery does not involve endocytosis or vesicle encapsulation of QDs. The amount of QD loading and the resulting cell viability can be adjusted by varying the parameters associated with the electroporation operation. To demonstrate the application of our approach for intracellular targeting, we study single-molecule motility of kinesin in live cells by labeling native kinesins using electroporation-delivered QDs. We envision that electroporation may serve as a simple and universal tool for delivering QDs into cells to label and probe native molecules and organelles

Visualization 1: Silica microwire-based interferometric electric field sensor

Sensor responding waveform to alternating electric field with 50 Hz. Originally published in Optics Letters on 15 August 2015 (ol-40-16-3683

Intracellular Tracking of Single Native Molecules with Electroporation-Delivered Quantum Dots

Quantum dots (QDs) have found a wide range of biological applications as fluorophores due to their extraordinary brightness and high photostability that are far superior to those of conventional organic dyes. These traits are particularly appealing for studying cell biology under a cellular autofluorescence background and with a long observation period. However, it remains the most important open challenge to target QDs at <i>native</i> intracellular molecules and organelles in <i>live</i> cells. Endocytosis-based delivery methods lead to QDs encapsulated in vesicles that have their surface biorecognition element hidden from the intracellular environment. The probing of native molecules using QDs has been seriously hindered by the lack of consistent approaches for delivery of QDs with exposed surface groups. In this study, we demonstrate that electroporation (i.e., the application of short electric pulses for cell permeabilization) generates reproducible results for delivering QDs into cells. We show evidence that electroporation-based delivery does not involve endocytosis or vesicle encapsulation of QDs. The amount of QD loading and the resulting cell viability can be adjusted by varying the parameters associated with the electroporation operation. To demonstrate the application of our approach for intracellular targeting, we study single-molecule motility of kinesin in live cells by labeling native kinesins using electroporation-delivered QDs. We envision that electroporation may serve as a simple and universal tool for delivering QDs into cells to label and probe native molecules and organelles

Screening Efficient C–N Coupling Catalysts for Electrosynthesis of Acetamide and Output Ammonia through a Cascade Strategy of Electrochemical CO₂ and N₂ Reduction Using Cu-Based Nitrogen–Carbon Nanosheets

Due to the limitation of the high-value-added products obtained from electrocatalytic CO2 reduction within an acid environment, introducing additional elements can expand the diversity of the products obtained during the CO2 reduction reaction (CO2RR) and nitrogen reduction reaction (NRR). Thus, coelectroreduction of CO2 and N2 is a new strategy for producing acetamide (CH3CONH2) via both C–C and C–N bond coupling using Cu-based nitrogen–carbon nanosheets. CO2 can reduce to CO, and a key ketene (*CCO) can be generated from *CO*CO dimerization; this ketene is postulated as an intermediate in the formation of acetamide. However, most studies focus on promoting the C–C bond formation. Here, we propose that C–N bond coupling can form acetamide through the interaction of *CCO with NH3. The acetamide is formed via a nucleophilic attack between *NH3 and the *CCO intermediate. The C–N coupling mechanism was successfully applied to expand the variety of nitrogen-containing products obtained from CO2 and N2 coreduction. Thus, we successfully screened Cu2-based graphite and Cu-based C3N4 as catalysts that can produce C2+ compounds by integrating CO dimerization with acetamide synthesis. In addition, we observed that Cu2-based C2N and Cu-based C3N4 catalysts are suitable for the NRR. Cu-based C3N4 showed high CO2RR and NRR activities with small negative limiting potential (UL) values of −0.83 and −0.58 V compared to those of other candidates, respectively. The formation of *COHCOH from *COHCO was considered the rate-determining step (RDS) during acetamide electrosynthesis. The limiting potential value of Cu2-based C2N was only −0.46 V for NH3 synthesis, and the formation of *NNH was via the RDS via an alternating path. The adsorption energy difference analysis both CO2 and N2 compare with the hydrogen evolution reaction (HER), suggesting that Cu2-based C2N exhibited the highest CO2RR and NRR selectivity among the 13 analyzed catalysts. The results of this study provide innovative insights into the design principle of Cu-based nitrogen–carbon electrocatalysts for generating highly efficient C–N coupling products

Copper-Catalyzed Cyclization for Access to 6<i>H</i>‑Chromeno[4,3‑<i>b</i>]quinolin-6-ones Employing DMF as the Carbon Source

The first example of the copper-catalyzed cyclization of 4-(phenylamino)-2<i>H</i>-chromen-2-ones employing the <i>N</i>-methyl moiety of DMF as the source of the methine (CH) group has been developed, providing an efficient synthetic pathway to access novel functionalized 6<i>H</i>-chromeno­[4,3-<i>b</i>]­quinolin-6-ones in moderate to good yields