RESUMO
Metabolic efficiency profoundly influences organismal fitness. Nonphotosynthetic organisms, from yeast to mammals, derive usable energy primarily through glycolysis and respiration. Although respiration is more energy efficient, some cells favor glycolysis even when oxygen is available (aerobic glycolysis, Warburg effect). A leading explanation is that glycolysis is more efficient in terms of ATP production per unit mass of protein (that is, faster). Through quantitative flux analysis and proteomics, we find, however, that mitochondrial respiration is actually more proteome efficient than aerobic glycolysis. This is shown across yeast strains, T cells, cancer cells, and tissues and tumors in vivo. Instead of aerobic glycolysis being valuable for fast ATP production, it correlates with high glycolytic protein expression, which promotes hypoxic growth. Aerobic glycolytic yeasts do not excel at aerobic growth but outgrow respiratory cells during oxygen limitation. We accordingly propose that aerobic glycolysis emerges from cells maintaining a proteome conducive to both aerobic and hypoxic growth.
Assuntos
Trifosfato de Adenosina , Glicólise , Mitocôndrias , Proteoma , Proteoma/metabolismo , Trifosfato de Adenosina/metabolismo , Mitocôndrias/metabolismo , Humanos , Animais , Saccharomyces cerevisiae/metabolismo , Proteômica/métodos , Camundongos , AerobioseRESUMO
Metabolic engineering aims to improve the production of economically valuable molecules through the genetic manipulation of microbial metabolism. While the discipline is a little over 30 years old, advancements in metabolic engineering have given way to industrial-level molecule production benefitting multiple industries such as chemical, agriculture, food, pharmaceutical, and energy industries. This review describes the design, build, test, and learn steps necessary for leading a successful metabolic engineering campaign. Moreover, we highlight major applications of metabolic engineering, including synthesizing chemicals and fuels, broadening substrate utilization, and improving host robustness with a focus on specific case studies. Finally, we conclude with a discussion on perspectives and future challenges related to metabolic engineering.
Assuntos
Indústrias , Engenharia MetabólicaRESUMO
MOTIVATION: Protein sequence comparison is a fundamental element in the bioinformatics toolkit. When sequences are annotated with features such as functional domains, transmembrane domains, low complexity regions or secondary structure elements, the resulting feature architectures allow better informed comparisons. However, many existing schemes for scoring architecture similarities cannot cope with features arising from multiple annotation sources. Those that do fall short in the resolution of overlapping and redundant feature annotations. RESULTS: Here, we introduce FAS, a scoring method that integrates features from multiple annotation sources in a directed acyclic architecture graph. Redundancies are resolved as part of the architecture comparison by finding the paths through the graphs that maximize the pair-wise architecture similarity. In a large-scale evaluation on more than 10 000 human-yeast ortholog pairs, architecture similarities assessed with FAS are consistently more plausible than those obtained using e-values to resolve overlaps or leaving overlaps unresolved. Three case studies demonstrate the utility of FAS on architecture comparison tasks: benchmarking of orthology assignment software, identification of functionally diverged orthologs, and diagnosing protein architecture changes stemming from faulty gene predictions. With the help of FAS, feature architecture comparisons can now be routinely integrated into these and many other applications. AVAILABILITY AND IMPLEMENTATION: FAS is available as python package: https://pypi.org/project/greedyFAS/.
Assuntos
Sequência de Aminoácidos , Proteínas , Alinhamento de Sequência , Software , Humanos , Biologia Computacional/métodos , Proteínas/química , Alinhamento de Sequência/métodos , Proteínas de Saccharomyces cerevisiae/químicaRESUMO
One of the most common adverse outcomes of an upper blepharoplasty involving double-eyelid surgery is asymmetric upper eyelids due to unbalanced supratarsal folds or a difference in the palpebral fissure height. This study aimed to evaluate the efficacy and safety of transconjunctival levator aponeurosis-Müller muscle complex plication for correcting acquired ptosis following double-eyelid surgery. This retrospective study evaluated 18 patients who underwent transconjunctival levator aponeurosis-Müller muscle complex plication between June 2016 and June 2019 to correct acquired ptosis. On the basis of the main area of eyelid drooping, ptosis was categorized as central (mid-pupillary), medial (medial limbus), or lateral (lateral limbus). Preoperative and postoperative palpebral fissure heights were measured and compared. Three months postsurgery, the mean difference in palpebral fissure height between bilateral eyes decreased from 0.96 to 0.04 mm in the medial ( P <0.001), from 0.93 to 0.00 mm in central ( P =0.003), and from 1.30 to -0.03 mm in lateral ptosis ( P =0.079). In 13 patients who underwent unilateral correction, the amount of plication was significantly associated with increased palpebral fissure height at the medial limbus ( P =0.043) and mid-pupillary line ( P =0.035). All patients reported a significant improvement in satisfaction. Five patients experienced acute postoperative complications, including chemosis, conjunctival injection, and foreign body sensation, all of which were resolved after a month of observation. No asymmetries or recurrences were observed. Transconjunctival levator aponeurosis-Müller muscle complex plication is a minimally invasive, safe, and effective technique for correcting acquired ptosis following upper eyelid surgery.
Assuntos
Aponeurose , Blefaroplastia , Blefaroptose , Músculos Oculomotores , Complicações Pós-Operatórias , Humanos , Blefaroptose/cirurgia , Blefaroplastia/métodos , Feminino , Masculino , Estudos Retrospectivos , Músculos Oculomotores/cirurgia , Pessoa de Meia-Idade , Aponeurose/cirurgia , Adulto , Túnica Conjuntiva/cirurgia , Pálpebras/cirurgia , Idoso , Resultado do TratamentoRESUMO
BACKGROUND: Nanofat and lipoconcentrate contain adipose-derived stem cells and growth factors, and have wide clinical applications in the regenerative field. This study aimed to investigate the microenvironmental changes associated with nanofat and lipoconcentrate. METHODS: Conventional fat, nanofat, or lipoconcentrate (0.2 mL each, n = 5 per group) were injected subcutaneously into the dorsal flanks of athymic nude mice. The graft weights were measured at postoperative week 4; the grafts and their overlying skin were used for histological analyses. RESULTS: Weights of the lipoconcentrate grafts were significantly greater than those of the conventional fat (p < 0.05) and nanofat (p < 0.01) grafts. There was no significant difference in inflammation, oil cysts, and fibrosis between the conventional fat and nanofat groups. Histological examination of the lipoconcentrate grafts showed less macrophage infiltration and the formation of fibrosis and oil cysts. Additionally, adipogenesis and angiogenesis were induced more in the lipoconcentrate grafts than in the nanofat grafts (p < 0.01). Lipoconcentrate and nanofat improved dermal thickness (p < 0.001 and p < 0.01, respectively, versus the baseline). CONCLUSION: Lipoconcentrate grafts had greater volume and shape retention than conventional fat and nanofat grafts. They had better histological structure and acted as scaffolds for adipogenesis and angiogenesis. Both products showed regenerative effects on dermal thickness; however, only lipoconcentrate grafts had the required volume and regenerative effects, allowing it to serve as a novel adipose-free grafting method for facial rejuvenation and contouring. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to Table of Contents or the online Instructions to Authors www.springer.com/00266 .
Assuntos
Adipogenia , Cistos , Animais , Camundongos , Camundongos Nus , Angiogênese , Fibrose , Tecido Adiposo/transplanteRESUMO
BACKGROUND: We previously showed comparable volume effects of injections of acellular adipose matrix (AAM), an adipose tissue-derived extracellular matrix, and conventional fat grafting in a murine model. Thus, AAM could be a novel allogenic injectable product. However, its retention rate poses a concern, as repeated AAM injections may be required in some cases. This study investigated the biological properties and therapeutic value of stored AAM and compared them with those of fresh AAM, in a murine model. METHODS: AAM was manufactured from fresh human abdominoplasty fat. Fresh and stored injectable AAM was prepared within 24 h and 3 months after generation, respectively. Either fresh or stored injectable AAM was injected into the scalp of athymic nude mice (0.2 mL/sample, n = 6 per group). After 8 weeks, graft retention was assessed through weight measurement, and histological analysis was performed, including immunofluorescence staining for CD31 and perilipin. RESULTS: Retention rate was significantly reduced in the stored compared to the fresh injectable AAM group. Nevertheless, histological analysis revealed comparable inflammatory cell presence, with minimal capsule formation, in both groups. Adipogenesis occurred in both groups, with no significant difference in the blood vessel area (%) between groups. CONCLUSIONS: Although the volume effects of stored AAM for soft tissue reconstruction were limited compared to those of fresh injectable AAM, stored AAM had similar capacity for adipogenesis and angiogenesis. This promising allogeneic injectable holds the potential to serve as an effective "off-the-shelf" alternative for repeated use within a 3-month storage period. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors https://link.springer.com/journal/00266 .
RESUMO
BACKGROUND: The extracellular matrix isolated from adipose tissue, known as acellular adipose matrix (AAM), represents a novel biomaterial. AAM functions as a scaffold that not only supports stem cell proliferation and differentiation but also induces adipogenesis and angiogenesis. This study aims to investigate the volumetric effects and microenvironmental changes associated with injectable AAM in comparison to conventional fat grafting. METHODS: AAM was manufactured from fresh human abdominoplasty fat using a mechanically modified method and then transformed into an injectable form. Lipoaspirate was harvested employing the Coleman technique. A weight and volume study was conducted on athymic nude mice by injecting either injectable AAM or lipoaspirate into the scalp (n=6 per group). After eight weeks, graft retention was assessed through weight measurement and volumetric analysis using micro-computed tomography (micro-CT) scanning. Histological analysis was performed using immunofluorescence staining for perilipin and CD31. RESULTS: Injectable AAM exhibited similar weight and volume effects in murine models. Histological analysis revealed comparable inflammatory cell presence with minimal capsule formation when compared to conventional fat grafts. Adipogenesis occurred in both AAM-injected and conventional fat graft models, with no significant difference in the blood vessel area (%) between the two. CONCLUSIONS: In summary, injectable AAM demonstrates effectiveness comparable to conventional fat grafting concerning volume effects and tissue regeneration in soft tissue reconstruction. This promising allogeneic injectable holds the potential to serve as a safe and effective "Off-the-Shelf" alternative in both aesthetic and reconstructive clinical practices. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .
Assuntos
Abdominoplastia , Tecido Adiposo , Camundongos Nus , Animais , Camundongos , Tecido Adiposo/transplante , Abdominoplastia/métodos , Humanos , Feminino , Procedimentos de Cirurgia Plástica/métodos , Modelos Animais de Doenças , Microtomografia por Raio-X , Adipogenia , Distribuição Aleatória , Sobrevivência de Enxerto , Modelos Animais , Matriz Extracelular/transplanteRESUMO
BACKGROUND: Cell-assisted acellular adipose matrix (AAM) transfer is a novel technique for soft tissue volume restoration, where AAM acts as a scaffold for tissue proliferation and promotes host cell migration, vascularization, and adipogenesis. This study aimed to evaluate the efficacy and safety of in vivo cell-assisted AAM transfer compared to hyaluronic acid (HA) filler injection. METHODS: Human adipose tissue was used to manufacture AAM, and murine adipose-derived stem cells (ASCs) were prepared. Nude mice were divided into four groups: AAM transfer (AT), ASC-assisted AAM transfer (CAT), HA filler injection (HI), and ASC-assisted HA filler injection (CHI). Eight weeks post-transfer, in vivo graft volume/weight, histology, and gene expression were analyzed to assess efficacy and safety. RESULTS: The AAM retained its three-dimensional scaffold structure without cellular components. AT/CAT showed lower volume retention than HA/CHA; however, CAT maintained a similar volume to HA. Histologically, adipogenesis and collagen formation were increased in AT/CAT compared to HA/CHA, with CAT showing the highest levels. CAT also demonstrated superior angiogenesis, adipogenesis, and gene expression (Vegf and Pparg), along with lower Il-6 expression, higher Il-10 expression, and reduced capsule formation, indicating better biocompatibility. CONCLUSIONS: Cell-assisted AAM transfer is a promising technique for volume retention and tissue regeneration, offering a safe and effective alternative to HA filler injections. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .
RESUMO
In this study, the features of resistive random access memory (RRAM) employing a straightforward Cr/MAPbI3 /FTO three-layer structure have been examined and clarified. The device displays various resistance switching (RS) behavior at various sweep voltages between 0.5 and 5â V. The RS effect has a conversion in the direction of the SET and RESET processes during sweeping for a number of cycles at a specific voltage. The directional change of the RS processes corresponds to the dominant transition between the generation/recombination of iodide ion and vacancy in the MAPbI3 perovskite layer and the electrochemical metallization of the Cr electrode under the influence of an electric field, which results in the conductive filament (CF) formation/rupture. At each stage, these processes are controlled by specific charge conduction mechanisms, including Ohmic conduction, space-charge-limited conduction (SCLC), and variable-range hopping (VRH). By identifying the biased voltage and the quantity of voltage sweep cycles, one can take a new approach to control or modulate the pathways for effective charge transport. This new approach is made possible by an understanding of the RS characteristics and the corresponding mechanisms causing the variation of RS behavior in the structure.
RESUMO
Ciprofloxacin (CFX) and ofloxacin (OFX) are commonly found as residual contaminants in aquatic environments, posing potential risks to various species. To ensure the safety of aquatic wildlife, it is essential to determine the toxicity of these antibiotics and establish appropriate concentration limits. Additionally, in (eco)toxicological studies, addressing the issue of multiple hypothesis testing through p-value adjustments is crucial for robust decision-making. In this study, we assessed the no observed adverse effect concentration (NOAEC) of CFX and OFX on Moina macrocopa across a concentration range of 0-400 µg L-1. Furthermore, we investigated multiple p-value adjustments to determine the NOAECs. Our analysis yielded consistent results across seven different p-value adjustments, indicating NOAECs of 100 µg CFX L-1 for age at first reproduction and 200 µg CFX L-1 for fertility. For OFX treatment, a NOAEC of 400 µg L-1 was observed for both biomarkers. However, further investigation is required to establish the NOAEC of OFX at higher concentrations with greater certainty. Our findings demonstrate that CFX exhibits higher toxicity compared to OFX, consistent with previous research. Moreover, this study highlights the differential performance of p-value adjustment methods in terms of maintaining statistical power while controlling the multiplicity problem, and their practical applicability. The study emphasizes the low NOAECs for these antibiotics in the zooplanktonic group, highlighting their significant risks to ecological and environmental safety. Additionally, our investigation of p-value adjustment approaches contributes to a deeper understanding of their performance characteristics, enabling (eco)toxicologists to select appropriate methods based on their specific needs and priorities.
RESUMO
The plant-sourced polyketide triacetic acid lactone (TAL) has been recognized as a promising platform chemical for the biorefinery industry. However, its practical application was rather limited due to low natural abundance and inefficient cell factories for biosynthesis. Here, we report the metabolic engineering of oleaginous yeast Rhodotorula toruloides for TAL overproduction. We first introduced a 2-pyrone synthase gene from Gerbera hybrida (GhPS) into R. toruloides and investigated the effects of different carbon sources on TAL production. We then systematically employed a variety of metabolic engineering strategies to increase the flux of acetyl-CoA by enhancing its biosynthetic pathways and disrupting its competing pathways. We found that overexpression of ATP-citrate lyase (ACL1) improved TAL production by 45% compared to the GhPS overexpressing strain, and additional overexpression of acetyl-CoA carboxylase (ACC1) further increased TAL production by 29%. Finally, we characterized the resulting strain I12-ACL1-ACC1 using fed-batch bioreactor fermentation in glucose or oilcane juice medium with acetate supplementation and achieved a titer of 28 or 23 g/L TAL, respectively. This study demonstrates that R. toruloides is a promising host for the production of TAL and other acetyl-CoA-derived polyketides from low-cost carbon sources.
Assuntos
Engenharia Metabólica , Policetídeos , Acetilcoenzima A , Carbono , Engenharia Metabólica/métodos , Policetídeos/metabolismo , Pironas , Rhodotorula , Leveduras/metabolismoRESUMO
TiO2 is a well-known semiconductor used widely in the photocatalyst field, but its photocatalytic applications are hampered by a fast electron-hole recombination rate and low visible light absorption due to a wide-band-gap energy. Herein, we present a simple, low cost, and green approach to obtain carbon dots from microalgae, namely microalgae-based carbon dots (MCDs), using an unprecedented microwave-assisted treatment. The MCDs were successfully decorated on the surface of TiO2 nanoparticles. The as-prepared composite exhibited a superior photodegradation of methylene blue, compared with pristine TiO2 (83% and 27%, respectively) under visible light irradiation. The MCDs in TiO2-MCDs serve as electron reservoirs to trap photoinduced electrons and as photosensitizers for the improvement of visible light absorption; both factors play an important role in the improvement of the TiO2 photocatalytic activity. Furthermore, the as-prepared composite photocatalyst also exhibits high photostability and recyclability during the photodegradation of methylene blue. Therefore, this work provides an original approach to the development of environmentally friendly and highly effective photocatalysts for the treatment of various organic pollutants, which can go a long way toward ensuring a safe and sustainable environment.
Assuntos
Microalgas , Nanopartículas , Carbono , Catálise , Fotólise , TitânioRESUMO
The design and fabrication of nanoscale multilayered thin films play an essential role in regulating the operation efficiency of sensitive optical sensors and filters. In this paper, we introduce a packaged tool that employs flexible electromagnetic calculation software with machine learning in order to find the optimized double-band antireflection coatings in intervals of wavelength from 3 to 5 µm and 8 to 12 µm. Instead of computing or modeling an extremely enormous set of thin film structures, this tool enhanced with machine learning can swiftly predict the optical properties of a given structure with >99.7% accuracy and a substantial reduction in computation costs. Furthermore, the tool includes two learning methods that can infer a global optimal structure or suitable local optimal ones. Specifically, these well-trained models provide the highest accurate double-band average transmission coefficient combined with the lowest number of layers or the thinnest total thickness starting from a reference multilayered structure. Finally, the more sophisticated enhancement method, called the double deep Q-learning network, exhibited the best performance in finding optimal antireflective multilayered structures with the highest double-band average transmission coefficient of about 98.95%.
RESUMO
Organic acids are an important class of compounds that can be produced by microbial conversion of renewable feedstocks and have huge demands and broad applications in food, chemical, and pharmaceutical industries. An economically viable fermentation process for production of organic acids requires robust microbial cell factories with excellent tolerance to low pH conditions, high concentrations of organic acids, and lignocellulosic inhibitors. In this review, we summarize various strategies to engineer robust microorganisms for organic acid production and highlight their applications in a few recent examples.
Assuntos
Ácidos , Compostos Orgânicos , Fermentação , Engenharia MetabólicaRESUMO
BACKGROUND: This study was conducted to evaluate the surgical results of the arterial switch operation for Taussig-Bing variants, at a single institution in a lower-middle income country. METHODS: Between June 2010 and December 2018, all consecutive patients diagnosed with Taussig-Bing variants who underwent the arterial switch operation and ventricular septal defect closure were included in the study. RESULTS: A total of 72 patients of Taussig-Bing variants underwent arterial switch operation and ventricular septal defect closure. There were 10 early deaths (13.9%) and 2 late deaths (2.8%). Intraoperative ventricular septal defect enlargement (hazard ratio [HR] 7.23, 95% confidence interval [CI] 3.1294-16.7167; p < .001), secondary aortic cross-clamping (HR 28.38, 95% CI 4.8427-166.3484; p < .001), postoperative pneumonia (HR 5.64, 95% CI 1.2724-24.9917; p = .023), and postoperative sepsis (HR 5.28, 95% CI 1.3512-20.6553; p = .017) were risk factors for overall mortality by competing risk analysis. Sixty patients (83.3%) required septoparietal trabeculation division/resection during the arterial switch operation in an attempt to avoid right ventricular outflow tract obstruction. The reoperation rate for right ventricular outflow tract obstruction at last follow up was 6% (three patients). The estimated freedom from reoperation for right ventricular outflow tract obstruction at 1, 5, and 9 years was 98.3%, 91.9%, and 91.9%, respectively. CONCLUSIONS: The results of arterial switch operation for Taussig-Bing variants were satisfactory in the operative setting of a lower-middle income country, and performing extensive septoparietal trabeculation division might reduce the reintervention rate for right ventricular outflow tract obstruction in these patients.
Assuntos
Transposição das Grandes Artérias , Dupla Via de Saída do Ventrículo Direito , Transposição dos Grandes Vasos , Transposição das Grandes Artérias/efeitos adversos , Dupla Via de Saída do Ventrículo Direito/cirurgia , Seguimentos , Humanos , Lactente , Reoperação , Estudos Retrospectivos , Transposição dos Grandes Vasos/complicações , Resultado do TratamentoRESUMO
Taking advantage of the known planarity of the N-acetyl group of N-acetylglucosamine, an analysis of the quality of carbohydrate structures found in the protein databank was performed. Few obvious defects of the local geometry of the carbonyl group were observed. However, the N-acetyl group was often found in the less favorable cis conformation (12% of the cases). It was also found severely twisted in numerous instances, especially in structures with a resolution poorer than 1.9 Å determined between 2000 and 2015. Though the automated PDB-REDO procedure has proved able to improve nearly 85% of the structural models deposited to the PDB, and does prove able to cure most severely twisted conformations of the N-acetyl group, it fails to correct its high rate of cis conformations. More generally, for structures with a resolution poorer than 1.6 Å, it produces N-acetylglucosamine models in slightly poorer agreement with experimental data, as measured using real-space correlation coefficients. Significant improvements are thus still needed, at least as far as this carbohydrate structure is concerned.
Assuntos
Acetilglucosamina/química , Artefatos , Proteínas/química , Acetilglucosamina/metabolismo , Sítios de Ligação , Cristalografia por Raios X , Bases de Dados como Assunto , Bases de Dados de Proteínas , Humanos , Modelos Moleculares , Conformação Molecular , Ligação Proteica , Proteínas/metabolismoRESUMO
The nonconventional yeast Issatchenkia orientalis can grow under highly acidic conditions and has been explored for production of various organic acids. However, its broader application is hampered by the lack of efficient genetic tools to enable sophisticated metabolic manipulations. We recently constructed an episomal plasmid based on the autonomously replicating sequence (ARS) from Saccharomyces cerevisiae (ScARS) in I. orientalis and developed a CRISPR/Cas9 system for multiplexed gene deletions. Here we report three additional genetic tools including: (1) identification of a 0.8 kb centromere-like (CEN-L) sequence from the I. orientalis genome by using bioinformatics and functional screening; (2) discovery and characterization of a set of constitutive promoters and terminators under different culture conditions by using RNA-Seq analysis and a fluorescent reporter; and (3) development of a rapid and efficient in vivo DNA assembly method in I. orientalis, which exhibited ~100% fidelity when assembling a 7 kb-plasmid from seven DNA fragments ranging from 0.7 kb to 1.7 kb. As proof of concept, we used these genetic tools to rapidly construct a functional xylose utilization pathway in I. orientalis.
Assuntos
Sistemas CRISPR-Cas , DNA Fúngico , Engenharia Metabólica , Pichia , DNA Fúngico/genética , DNA Fúngico/metabolismo , Pichia/genética , Pichia/metabolismo , Saccharomyces cerevisiae/genéticaRESUMO
In this work, we present the optical birefringence properties of the optical fiber cladding that exists as an evanescent field where the refractive index (RI) of the analysis solution is applied for optical sensor aspiration. To enhance the performance of the sensor, we have investigated the sensor with different thicknesses of TiO2 coating and bimetallic (Ag-Al) film alloy combinations by thermal evaporation coating. We described a special balanced homodyne detection method for the intensity difference change between the p- and s-polarization lights in the surface plasmon resonance sensing systems, which is strongly determined by the RI of the test medium. The plasmonic optical fiber can measure a very small change of the RI of a glycerol solution, which is a resolution of 4.37 × 10-8 RI unit (RIU). This method has great advantages of a small-sized optical setup, high stability, high selectivity, easy chemical modification, and low cost. Furthermore, because of the experiment results, we observe that our approach can also eliminate the surrounding noise in the Mach-Zehnder interferometer, which shows the feasibility of this proposed technique. We demonstrate the fluorescence enhancement in detecting the C-reactive protein antibody conjugated with fluorescein isothiocyanate by means of near-field coupling between surface plasmons and fluorophores at spectral channels of emission. This technique can also be extended for application in a biomedical assay and in biochemical science, including molecular diagnostics relying on multichannels that require a small volume of the analyte at each channel which would suffer from the weakness of fluorescence if it were not for the enhancement technology.
RESUMO
The transparent-conducting performance is estimated through figure-of-merit (FOM) value. To improve poor FOM value of pure ZnO thin films, boron (B) as a donor impurity was doped into the films. Direct-current magnetron sputtering was used to prepare B-doped ZnO (BZO) thin films from sintered ZnO targets with variable B2O3 content changing from 0 to 2 wt. %. The x ray diffraction analysis confirmed the preferably c-axis-oriented structure of hexagonal wurtzite ZnO host. The results also showed variation in the film structure versus the B2O3 content through calculations of crystal size and residual stress. Depending on the B2O3 content, a competition of interstitial and substitutional B3+ ions induced more stress or relaxation in lattice structure of the films. At 1% B2O3, the BZO thin film had the best crystalline characterization with the lowest stress and large crystal size. In consequence, the BZO 1% film obtained the lowest resistivity of 2.7×10-3Ωcm, average transmittance of 82.1%, and the best FOM value of 18.8×102Ω-1cm-1. The transparent-conducting performance of the ZnO thin films deposited by direct-current (DC) magnetron sputtering was significantly enhanced through B doping. The good-performance BZO film at 1% B2O3 is believed to be of use as electrodes in thin-film solar cells.