RESUMEN
Adaptive laboratory evolution (ALE) is a powerful approach for improving phenotypes of microbial hosts. Evolved strains typically contain numerous mutations that can be revealed by whole-genome sequencing. However, determining the contribution of specific mutations to new phenotypes is typically challenging and laborious. This task is complicated by factors such as the mutation type, the genomic context, and the interplay between different mutations. Here, a novel approach was developed to identify the significance of mutations in strains evolved from Acinetobacter baylyi ADP1. This method, termed rapid advantageous mutation screening and selection (RAMSES), was used to analyze mutants that emerged from stepwise adaptation to and consumption of high levels of ferulate, a common lignin-derived aromatic compound. After whole-genome sequence analysis, RAMSES allowed rapid determination of effective mutations and seamless introduction of the beneficial mutations into the chromosomes of new strains with different genetic backgrounds. This simple approach to reverse engineering exploits the natural competence and high recombination efficiency of ADP1. Mutated DNA, added directly to growing cells, replaces homologous chromosomal regions to generate transformants that will become enriched if there is a selective benefit. Thus, advantageous mutations can be rapidly identified. Here, the growth advantage of transformants under selective pressure revealed key mutations in genes related to aromatic transport, including hcaE, hcaK, and vanK, and a gene, ACIAD0482, which is associated with lipopolysaccharide synthesis. This study provided insights into the enhanced utilization of industrially relevant aromatic substrates and demonstrated the use of A. baylyi ADP1 as a convenient platform for strain development and evolution studies. IMPORTANCE Microbial conversion of lignin-enriched streams is a promising approach for lignin valorization. However, the lignin-derived aromatic compounds are toxic to cells at relevant concentrations. Although adaptive laboratory evolution (ALE) is a powerful approach to develop more tolerant strains, it is typically laborious to identify the mechanisms underlying phenotypic improvement. We employed Acinetobacter baylyi ADP1, an aromatic-compound-degrading strain that may be useful for biotechnology. The natural competence and high recombination efficiency of this strain can be exploited for critical applications, such as the breakdown of lignin and plastics and abundant polymers composed of aromatic subunits. The natural transformability of this bacterium enabled us to develop a novel approach for rapid screening of advantageous mutations from ALE-derived, aromatic-tolerant, ADP1-derived strains. We clarified the mechanisms and genetic targets for improved tolerance toward common lignin-derived aromatic compounds. This study facilitates metabolic engineering for lignin valorization.
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Acinetobacter , Acinetobacter/metabolismo , Lignina/metabolismo , Ingeniería Metabólica , MutaciónRESUMEN
BACKGROUND: Long non-coding RNA (LncRNA) HOTAIR was amplified and overexpressed in many human carcinomas, which could serve as a useful target for cancer early detection and treatment. The 99mTc radiolabeled antisense oligonucleotides (ASON) could visualize the expression of HOTAIR and provide a diagnostic value for malignant tumors. The aim of this study was to evaluate whether liposome-coated antisense oligonucleotide probe 99mTc-HYNIC-ASON targeting HOTAIR can be used in in vivo imaging of HOTAIR in malignant glioma xenografts. METHODS: The ASON targeting LncRNA HOTAIR as well as mismatched ASON (ASONM) were designed and modified. The radiolabeling of 99mTc with two probes were via the conjugation of bifunctional chelator HYNIC. Then probes were purified by Sephadex G25 and tested for their radiolabeling efficiency and purity, as well as stability by ITLC (Instant thin-layer chromatography) and gel electrophoresis. Then the radiolabeled probes were transfected with lipofectamine 2000 for cellular uptake test and the next experimental use. Furthermore, biodistribution study and SPECT imaging were performed at different times after liposome-coated 99mTc-HYNIC-ASON/ASONM were intravenously injected in glioma tumor-bearing mice models. All data were analyzed by statistical software. RESULTS: The labeling efficiencies of 99mTc-HYNIC-ASON and 99mTc-HYNIC-ASONM measured by ITLC were (91 ± 1.5) % and (90 ± 0.6) %, respectively, and both radiochemical purities were more than 89%. Two probes showed good stability within 12 h. Gel electrophoresis confirmed that the oligomers were successfully radiolabeled no significant degradation were found. Biodistribution study demonstrated that liposome-coated antisense probes were excreted mainly through the kidney and bladder and has higher uptake in the tumor. Meanwhile, the tumor was clearly shown after injection of liposome coated 99mTc-HYNIC-ASON, and its T/M ratio was higher than that in the non-transfection group and mismatched group. No tumor was seen in mismatched and blocking group. CONCLUSION: The liposome encapsulated 99mTc-HYNIC-ASON probe can be used in the in vivo, real-time imaging of LncRNA HOTAIR expression in malignant glioma.
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Glioma/diagnóstico por imagen , Oligonucleótidos Antisentido/administración & dosificación , Compuestos de Organotecnecio/administración & dosificación , ARN Largo no Codificante/análisis , Radiofármacos/administración & dosificación , Animales , Modelos Animales de Enfermedad , Xenoinjertos/metabolismo , Liposomas , Ratones , Distribución TisularRESUMEN
BACKGROUND: Dengue fever (DF), influenza, and hand, foot, and mouth disease (HFMD) have had several various degrees of outbreaks in China since the 1900s, posing a serious threat to public health. Previous studies have found that these infectious diseases were often prevalent in the same areas and during the same periods in China. METHODS: This study combined traditional descriptive statistics and spatial scan statistic methods to analyze the spatiotemporal features of the epidemics of DF, influenza, and HFMD during 2013-2015 in mainland China at the provincial level. RESULTS: DF got an intensive outbreak in 2014, while influenza and HFMD were stable from 2013 to 2015. DF mostly occurred during August-November, influenza appeared during November-next March, and HFMD happened during April-November. The peaks of these diseases form a year-round sequence; Spatially, HFMD generally has a much higher incidence than influenza and DF and covers larger high-risk areas. The hotspots of influenza tend to move from North China to the southeast coast. The southeastern coastal regions are the high-incidence areas and the most significant hotspots of all three diseases. CONCLUSIONS: This study suggested that the three diseases can form a year-round sequence in southern China, and the southeast coast of China is a particularly high-risk area for these diseases. These findings may have important implications for the local public health agency to allocate the prevention and control resources.
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Enfermedades Transmisibles , Enfermedad de Boca, Mano y Pie , Gripe Humana , Humanos , Enfermedad de Boca, Mano y Pie/epidemiología , Gripe Humana/epidemiología , China/epidemiología , Enfermedades Transmisibles/epidemiología , Incidencia , Análisis Espacio-TemporalRESUMEN
BACKGROUND: Integration of synthetic metabolic pathways to catabolically diverse chassis provides new opportunities for sustainable production. One attractive scenario is the use of abundant waste material to produce a readily collectable product, which can reduce the production costs. Towards that end, we established a cellular platform for the production of semivolatile medium-chain α-olefins from lignin-derived molecules: we constructed 1-undecene synthesis pathway in Acinetobacter baylyi ADP1 using ferulate, a lignin-derived model compound, as the sole carbon source for both cell growth and product synthesis. RESULTS: In order to overcome the toxicity of ferulate, we first applied adaptive laboratory evolution to A. baylyi ADP1, resulting in a highly ferulate-tolerant strain. The adapted strain exhibited robust growth in 100 mM ferulate while the growth of the wild type strain was completely inhibited. Next, we expressed two heterologous enzymes in the wild type strain to confer 1-undecene production from glucose: a fatty acid decarboxylase UndA from Pseudomonas putida, and a thioesterase 'TesA from Escherichia coli. Finally, we constructed the 1-undecene synthesis pathway in the ferulate-tolerant strain. The engineered cells were able to produce biomass and 1-undecene solely from ferulate, and excreted the product directly to the culture headspace. CONCLUSIONS: In this study, we employed a bacterium Acinetobacter baylyi ADP1 to integrate a natural aromatics degrading pathway to a synthetic production route, allowing the upgradation of lignin derived molecules to value-added products. We developed a highly ferulate-tolerant strain and established the biosynthesis of an industrially relevant chemical, 1-undecene, solely from the lignin-derived model compound. This study reports the production of alkenes from lignin derived molecules for the first time and demonstrates the potential of lignin as a sustainable resource in the bio-based synthesis of valuable products.
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Acinetobacter/metabolismo , Alquenos/metabolismo , Lignina/metabolismo , Redes y Vías Metabólicas , Acinetobacter/genética , Biomasa , Evolución Molecular Dirigida , Escherichia coli/enzimología , Escherichia coli/genética , Esterasas/genética , Ingeniería Metabólica , Pseudomonas putida/enzimología , Pseudomonas putida/genéticaRESUMEN
The control of the nanoscale composition and structure of alloy catalysts plays an important role in heterogeneous catalysis. This paper describes novel findings of an investigation for Pd-based nanoalloy catalysts (PdCo and PdCu) for ethanol oxidation reaction (EOR) in gas phase and alkaline electrolyte. Although the PdCo catalyst exhibits a mass activity similar to Pd, the PdCu catalyst is shown to display a much higher mass activity than Pd for the electrocatalytic EOR in alkaline electrolyte. This finding is consistent with the finding on the surface enrichment of Pd on the alloyed PdCu surface, in contrast to the surface enrichment of Co in the alloyed PdCo surface. The viability of C-C bond cleavage was also probed for the PdCu catalysts in both gas-phase and electrolyte-phase EOR. In the gas-phase reaction, although the catalytic conversion rate for CO2 product is higher over Pd than PdCu, the nanoalloy PdCu catalyst appears to suppress the formation of acetic acid, which is a significant portion of the product in the case of pure Pd catalyst. In the alkaline electrolyte, CO2 was detected from the gas phase above the electrolyte upon acid treatment following the electrolysis, along with traces of aldehyde and acetic acid. An analysis of the electrochemical properties indicates that the oxophilicity of the base metal alloyed with Pd, in addition to the surface enrichment of metals, may have played an important role in the observed difference of the catalytic and electrocatalytic activities. In comparison with Pd alloyed with Co, the results for Pd alloyed with Cu showed a more significant positive shift of the reduction potential of the oxygenated Pd species on the surface. These findings have important implications for further fine-tuning of the Pd nanoalloys in terms of base metal composition toward highly active and selective catalysts for EOR.
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Aleaciones/química , Etanol/química , Nanoestructuras/química , Paladio/química , Catálisis , Cobalto/química , Cobre/química , Electroquímica , Gases/química , Concentración de Iones de Hidrógeno , Oxidación-Reducción , Propiedades de SuperficieRESUMEN
Recently, airflow sensors have attracted great attention due to their unique characteristics. However, the preparation of high-performance airflow sensors via extraordinarily simple, controllable and cost-effective methods remains a great challenge. Herein, inspired by the fluff system of the spider, an ultrasensitive fluffy-like airflow sensor with carbon fibers (CFs) uniformly and firmly planted on the surface of a polyvinyl alcohol (PVA) fibrous substrate has been easily fabricated using electrostatic flocking technology. The fluffy-like structure endows the airflow sensor with superior properties including ultra-sensitivity, fast response time (0.103 s), low airflow velocity detection limit (0.068 m s-1), ultra-sensitive detection in a wide airflow range (0.068-16 m s-1), and multi-directional consistent response to airflow. This sensor can be used to accurately recognize sound waves and voiceless speech and detect human and object motions in different postures and speeds. This work presents insights into designing and preparing high-performance airflow sensors on a large-scale for sound recognition, motion monitoring, and assisting the disabled.
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Dispositivos Electrónicos Vestibles , Movimiento (Física) , Alcohol Polivinílico , Sonido , Electricidad EstáticaRESUMEN
OBJECTIVE: To determine the expression and localization of transforming growth factor (TGF)-beta1 in condylar cartilage of adolescent rats following occlusion vertical rising procedures. METHODS: Forty male rats of 5 weeks of age were randomly divided into the experiment group (n=20) and the control group (n=20). The rats in the experiment group were fitted with upper posterior bite rising splints on their upper molar. Five rats from each group were killed at 7, 14, 21 and 28 days after the procedures, and their left condylar cartilages were taken for the determination of the expression of TGF-beta1 through SABC. RESULTS: The rats in the experiment group had significantly less expression of TGF-beta1 in condylar cartilage than the controls. The rats in the experiment group had the lowest TGF-beta17 day after the procedure. The level of TGF-beta1 increased over time. More TGF-beta1 positive cells were found in the rats of the experiment group than those in the control 28 days after the procedure. CONCLUSION: Occlusal vertical rising stimulates the expression of TGF-beta1 in condylar cartilage, which may be part of the adaptive remodeling of condylar cartilage in adolescent rats.
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Cartílago Articular/metabolismo , Oclusión Dental , Cóndilo Mandibular/metabolismo , Factor de Crecimiento Transformador beta/metabolismo , Animales , Cartílago Articular/crecimiento & desarrollo , Masculino , Cóndilo Mandibular/crecimiento & desarrollo , Distribución Aleatoria , Ratas , Ratas WistarRESUMEN
Hand-foot-and-mouth disease (HFMD) is an infectious disease of infants and young children frequently caused by the enterovirus A species, mainly enterovirus 71 (EV71) and coxsackievirus A16 (CA16). In this study, we prepared the EV71 virus-like particle (EV71-VLP) and its chimeras using recombinant baculovirus (Bac-P1-3CD) co-expressing EV71 P1 (under polyhedrin promoter) and 3CD (under CMV-IE promoter) proteins in Sf9 cells. EV71-VLP chimera ChiEV71(1E)-VLP or ChiEV71(4E)-VLP displayed single CA16 PEP71 epitope in VP1 or four conserved CA16 neutralizing epitopes (PEP71 in VP1, aa136-150 in VP2, aa176-190 in VP3 and aa48-62 in VP4) by substitution of the corresponding regions of EV71 structure proteins, respectively. In mice, EV71-VLP and its chimeras elicited similar EV71-specific IgG and neutralizing antibody (NAb) titers compared to inactivated EV71. Expectedly, vaccination of ChiEV71(1E)-VLP or ChiEV71(4E)-VLP resulted in significantly increased CA16-specific IgG and NAb production and improved cross-protection against CA16 infection compared to EV71-VLP. Interestingly, the VLPs induced potent cellular immune responses and significantly decreased Th2 type (IL-4 and IL-10) cytokines secretion in the splenocytes of immunized mice compared to inactivated EV71 or inactivated CA16. Neonatal mice born to dams immunized with the chimeric VLPs or neonatal mice passively transferred with sera of immunized mice were completely protected from lethal EV71 challenge and partially protected from lethal CA16 infection. Our study provides a novel bivalent or multivalent vaccine strategy to prevent EV71 and related-enterovirus infections.
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Enterovirus Humano A , Enterovirus , Enfermedad de Boca, Mano y Pie , Vacunas Virales , Animales , Anticuerpos Neutralizantes , Anticuerpos Antivirales , Quimera , Protección Cruzada , Enterovirus Humano A/genética , Epítopos/genética , Enfermedad de Boca, Mano y Pie/prevención & control , Ratones , Vacunas Virales/genéticaRESUMEN
BACKGROUND CONTEXT: Although vertebral augmentation with bone cement has been commonly used to treat symptomatic osteoporotic vertebral compression fractures, relatively little is known about the impact of augmentation on the adjacent spinal components. PURPOSE: To determine the imaging effects of vertebral augmentation on the adjacent discs, the augmented vertebra, and the involved spinal segment. STUDY DESIGN: Retrospective radiographic study. PATIENT SAMPLE: Patients with acute osteoporotic vertebral compression fractures who underwent vertebral augmentation or nonoperative treatments. OUTCOME MEASURES: On baseline and follow-up mid-sagittal T2W magnetic resonance images, quantitative measurements of disc degeneration, including disc height, bulging, and signal, vertebral height, wedge angle, and segmental kyphotic angle were acquired. METHODS: Lumbar spine magnetic resonance images of patients with acute osteoporotic vertebral compression fractures at a local hospital in Eastern China between 2010 and 2017 were reviewed. Student's t-tests and χ2 tests were used to examine the differences of baseline and changes over time between vertebrae underwent vertebral augmentation and those did not. Paired t-tests were used to examine the differences between baseline and follow-up to study the changes of adjacent disc degeneration, creep deformity of the vertebra and progression of segmental kyphosis. RESULTS: There were 112 acute vertebral compression fractures (72 treated with kyphoplasty and 40 with nonoperative treatments) in 101 subjects. At final follow-up (mean 21.5 months), the cranial disc of the augmented vertebra decreased in height (p<.001), and both cranial and caudal discs decreased in signal intensity (p≤.02). The discs in the nonoperative group did not undergo such degenerative changes. For the fractured vertebra, vertebral height significantly decreased (p<.01 for both) and vertebral wedge angle significantly increased (p≤.01 for both), regardless of augmentation treatment or not. Segmental kyphotic angle significantly increased in vertebral fractures that underwent vertebral augmentation (p<.001), but not in those underwent nonoperative treatments. CONCLUSIONS: Patients that underwent vertebral augmentation had more advanced disc degeneration at adjacent disc levels as compared to those without augmentation. The fractured vertebral body height decreased and the wedge angle increased, regardless of vertebral augmentation treatment or not. Vertebral augmentation may be associated with increased creep deformity of the adjacent vertebra and the progression of segmental kyphosis.
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Fracturas por Compresión , Cifoplastia , Fracturas Osteoporóticas , Fracturas de la Columna Vertebral , Cementos para Huesos , China , Fracturas por Compresión/diagnóstico por imagen , Fracturas por Compresión/cirugía , Humanos , Vértebras Lumbares/diagnóstico por imagen , Vértebras Lumbares/lesiones , Fracturas Osteoporóticas/diagnóstico por imagen , Estudios Retrospectivos , Fracturas de la Columna Vertebral/diagnóstico por imagen , Fracturas de la Columna Vertebral/terapia , Vértebras Torácicas/lesiones , Resultado del TratamientoRESUMEN
Fibrous materials serve as an intriguing class of 3D materials to meet the growing demands for flexible, foldable, biocompatible, biodegradable, disposable, inexpensive, and wearable sensors and the rising desires for higher sensitivity, greater miniaturization, lower cost, and better wearability. The use of such materials for the creation of a fibrous sensor substrate that interfaces with a sensing film in 3D with the transducing electronics is however difficult by conventional photolithographic methods. Here, a highly effective pathway featuring surface-mediated interconnection (SMI) of metal nanoclusters (NCs) and nanoparticles (NPs) in fibrous materials at ambient conditions is demonstrated for fabricating fibrous sensor substrates or platforms. Bimodally distributed gold-copper alloy NCs and NPs are used as a model system to demonstrate the semiconductive-to-metallic conductivity transition, quantized capacitive charging, and anisotropic conductivity characteristics. Upon coupling SMI of NCs/NPs as electrically conductive microelectrodes and surface-mediated assembly (SMA) of the NCs/NPs as chemically sensitive interfaces, the resulting fibrous chemiresistors function as sensitive and selective sensors for gaseous and vaporous analytes. This new SMI-SMA strategy has significant implications for manufacturing high-performance fibrous platforms to meet the growing demands of the advanced multifunctional sensors and biosensors.
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Celulosa/química , Nanopartículas del Metal/química , Nanotecnología/instrumentación , Electrodos , Propiedades de SuperficieRESUMEN
Tumors deficient in the urea cycle enzymes argininosuccinate synthase-1 (ASS1) and ornithine transcarbamylase (OTC) are unable to synthesize arginine and can be targeted using arginine-deprivation therapy. Here, we show that colorectal cancers (CRCs) display negligible expression of OTC and, in subset of cases, ASS1 proteins. CRC cells fail to grow in arginine-free medium and dietary arginine deprivation slows growth of cancer cells implanted into immunocompromised mice. Moreover, we report that clinically-formulated arginine-degrading enzymes are effective anticancer drugs in CRC. Pegylated arginine deiminase (ADI-PEG20), which degrades arginine to citrulline and ammonia, affects growth of ASS1-negative cells, whereas recombinant human arginase-1 (rhArg1peg5000), which degrades arginine into urea and ornithine, is effective against a broad spectrum of OTC-negative CRC cell lines. This reflects the inability of CRC cells to recycle citrulline and ornithine into the urea cycle. Finally, we show that arginase antagonizes chemotherapeutic drugs oxaliplatin and 5-fluorouracil (5-FU), whereas ADI-PEG20 synergizes with oxaliplatin in ASS1-negative cell lines and appears to interact with 5-fluorouracil independently of ASS1 status. Overall, we conclude that CRC is amenable to arginine-deprivation therapy, but we warrant caution when combining arginine deprivation with standard chemotherapy.
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Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Arginina/antagonistas & inhibidores , Argininosuccinato Sintasa/metabolismo , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/patología , Anciano , Animales , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Arginasa/farmacología , Arginasa/uso terapéutico , Arginina/metabolismo , Línea Celular Tumoral , Colon/patología , Neoplasias Colorrectales/mortalidad , Interacciones Farmacológicas , Sinergismo Farmacológico , Estudios de Factibilidad , Femenino , Fluorouracilo/farmacología , Fluorouracilo/uso terapéutico , Estudios de Seguimiento , Humanos , Hidrolasas/farmacología , Hidrolasas/uso terapéutico , Concentración 50 Inhibidora , Estimación de Kaplan-Meier , Masculino , Ratones , Ornitina Carbamoiltransferasa/metabolismo , Oxaliplatino/farmacología , Oxaliplatino/uso terapéutico , Polietilenglicoles/farmacología , Polietilenglicoles/uso terapéutico , Proteínas Recombinantes/farmacología , Proteínas Recombinantes/uso terapéutico , Estudios Retrospectivos , Resultado del Tratamiento , Urea/metabolismo , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
INTRODUCTION: Osteoporotic vertebral fractures can be treated by injecting bone cement into the damaged vertebral body. "Vertebroplasty" is becoming popular but the procedure has yet to be optimised. This study compared the ability of two different types of cement to restore the spine's mechanical properties following fracture, and it examined how the mechanical efficacy of vertebroplasty depends on bone mineral density (BMD), fracture severity, and disc degeneration. METHODS: A pair of thoracolumbar "motion-segments" (two adjacent vertebrae with intervening soft tissue) was obtained from each of 15 cadavers, aged 51-91 years. Specimens were loaded to induce vertebral fracture; then one of each pair underwent vertebroplasty with polymethylmethacrylate (PMMA) cement, the other with another composite material (Cortoss). Specimens were creep loaded for 2 h to allow consolidation. At each stage of the experiment, motion segment stiffness in bending and compression was measured, and the distribution of compressive loading on the vertebrae was investigated by pulling a miniature pressure transducer through the intervertebral disc. Pressure measurements, repeated in flexed and extended postures, indicated the intradiscal pressure (IDP) and neural arch compressive load-bearing (F(N)). BMD was measured using DXA. Fracture severity was quantified from height loss. RESULTS: Vertebral fracture reduced motion segment stiffness in bending and compression, by 31% and 43% respectively (p<0.001). IDP fell by 43-62%, depending on posture (p<0.001), whereas F(N) increased from 14% to 37% of the applied load in flexion, and from 39% to 61% in extension (p<0.001). Vertebroplasty partially reversed all these effects, and the restoration of load-sharing was usually sustained after creep-consolidation. No differences were observed between PMMA and Cortoss. Pooled results from 30 specimens showed that low BMD was associated with increased fracture severity (in terms of height loss) and with greater changes in stiffness and load-sharing following fracture. Specimens with low BMD and more severe fractures also showed the greatest mechanical changes following vertebroplasty. CONCLUSIONS: Low vertebral BMD leads to greater changes in stiffness and spinal load-sharing following fracture. Restoration of mechanical function following vertebroplasty is little influenced by cement type but may be greater in people with low BMD who suffer more severe fractures.
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Cementos para Huesos , Densidad Ósea , Enfermedades de la Columna Vertebral/metabolismo , Enfermedades de la Columna Vertebral/cirugía , Fracturas de la Columna Vertebral/cirugía , Columna Vertebral/metabolismo , Columna Vertebral/cirugía , Anciano , Anciano de 80 o más Años , Fenómenos Biomecánicos , Femenino , Humanos , Técnicas In Vitro , Disco Intervertebral/cirugía , Masculino , Ensayo de Materiales , Persona de Mediana Edad , Osteoporosis/complicaciones , Osteoporosis/metabolismo , Polimetil Metacrilato , Fracturas de la Columna Vertebral/etiología , Fracturas de la Columna Vertebral/metabolismoRESUMEN
Some bacterial strains such as Komagataeibacter xylinus are able to produce cellulose as an extracellular matrix. In comparison to wood-based cellulose, bacterial cellulose (BC) holds interesting properties such as biodegradability, high purity, water-holding capacity, and superior mechanical and structural properties. Aiming toward improvement in BC production titer and tailored alterations to the BC film, we engineered K. xylinus to overexpress partial and complete bacterial cellulose synthase operon that encodes activities for BC production. The changes in cell growth, end metabolite, and BC production titers from the engineered strains were compared with the wild-type K. xylinus. Although there were no significant differences between the growth of wild-type and engineered strains, the engineered K. xylinus strains demonstrated faster BC production, generating 2-4-fold higher production titer (the highest observed titer was obtained with K. xylinus-bcsABCD strain producing 4.3 ± 0.46 g/L BC in 4 days). The mechanical and structural characteristics of cellulose produced from the wild-type and engineered K. xylinus strains were analyzed with a stylus profilometer, in-house built tensile strength measurement system, a scanning electron microscope, and an X-ray diffractometer. Results from the profilometer indicated that the engineered K. xylinus strains produced thicker BC films (wild type, 5.1 µm, and engineered K. xylinus strains, 6.2-10.2 µm). Scanning electron microscope revealed no principal differences in the structure of the different type BC films. The crystallinity index of all films was high (from 88.6 to 97.5%). All BC films showed significant piezoelectric response (5.0-20 pC/N), indicating BC as a promising sensor material.
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Celulosa/química , Gluconacetobacter xylinusRESUMEN
While conformal and wearable devices have become one of the most desired formats for printable electronics, it is challenging to establish a scalable process that produces stable conductive patterns but also uses substrates compatible with widely available wearable materials. Here, we describe findings of an investigation of a nanoalloy ink printed and pulsed-laser sintered conductive patterns as flexible functional devices with enhanced stability and materials compatibility. While nanoparticle inks are desired for printable electronics, almost all existing nanoparticle inks are based on single-metal component, which, as an electronic element, is limited by its inherent stabilities of the metal such as propensity of metal oxidation and mobility of metal ions, especially in sintering processes. The work here has demonstrated the first example in exploiting plasmonic coupling of nanoalloys and pulsed-laser energy with controllable thermal penetration. The experimental and theoretical results have revealed clear correlation between the pulsed laser parameters and the nanoalloy structural characteristics. The superior performance of the resulting flexible sensor device, upon imparting nanostructured sensing materials, for detecting volatile organic compounds has significant implications to developing stable and wearable sensors for monitoring environmental pollutants and breath biomarkers. This simple "nanoalloy printing-laser sintering-nanostructure printing" process is entirely general to many different sensor devices and nanostructured sensing materials, enabling the ability to easily construct sophisticated sensor array.
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Aleaciones/química , Rayos Láser , Nanopartículas del Metal/química , Impresión , Compuestos Orgánicos Volátiles/análisis , TintaRESUMEN
AIM: Gastroesophageal reflux disease (GERD) is a common disorder in the Western population, but detailed population-based data in China are limited. The aim of this study was to understand the epidemiology of symptomatic gastroesophageal reflux (SGER) in adults of Xi'an, a northwestern city of China, and to explore the potential risk factors of GERD. METHODS: Symptoms suggestive of GERD, functional dyspepsia (FD), irritable bowel syndrome (IBS), upper respiratory diseases and some potential risk factors were investigated in a face-to-face manner in a region-stratified random samples of 2789 residents aged 18-70 years in Xi'an by using a standardized questionnaire. METHODS: With a response rate of 91.8%, the prevalence of SGER was 16.98% (95% CI, 14.2-18.92) in Xi'an adults, and no gender-related difference was observed (P<0.05). SGER was more common among subjects aged 30-70 years than in those aged 18-29 years (P<0.01). The prevalence of SGER in rural, urban and suburban subjects was 21.07%, 17.44% and 12.12%, respectively, and there was a significant difference between rural, urban and suburban regions (P<0.05). Compared with subjects without SGER, the prevalence of symptoms suggestive of FD and IBS, pneumonia, asthma, bronchitis, laryngitis, pharyngitis, chronic cough, wheeze, globus sensation, oral ulcer and snore was significantly increased in subjects with SGER (P<0.01). Heavy smoking (OR=5.76; CI, 3.70-6.67), heavy alcohol use (OR=2.85; CI, 1.67-4.49), peptic ulcer (OR=5.76; CI, 3.99-8.32), cerebral palsy (OR=3.97; CI, 1.97-8.00), abdominal operation (OR=2.69; CI, 1.75-4.13), obesity (OR=2.16; CI, 1.47-3.16), excessive food intake (OR=1.43; CI, 1.17-1.15), sweet food (OR=1.23; CI, 0.89-1.54), and consumption of coffee (OR=1.23; CI, 0.17-2.00) were independently associated with SGER. The episodes of GERD were commonly precipitated by dietary factors (66.05%), followed by body posture (26.54%), ill temper (23.72%), fatigue (22.32%) and stress (10.93%). CONCLUSION: GERD is common in Xi'an's adult population with a mild or moderate degree. The etiology and pathogenesis of GERD are probably associated with FD, IBS, and some respiratory, laryngopharyngeal and odontostological diseases or symptoms. Some lifestyles, diseases and dietary factors are the risk factors of GERD.
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Reflujo Gastroesofágico/epidemiología , Adolescente , Adulto , Distribución por Edad , Anciano , China/epidemiología , Femenino , Humanos , Laringitis/epidemiología , Enfermedades Pulmonares/epidemiología , Masculino , Persona de Mediana Edad , Faringitis/epidemiología , Prevalencia , Factores de Riesgo , Población Rural/estadística & datos numéricos , Distribución por Sexo , Encuestas y Cuestionarios , Población Urbana/estadística & datos numéricosRESUMEN
OBJECTIVE: To explore the surgical approaches to obtain good aesthetic and functional results in the management of orbital and periorbital fibrous dysplasia and related deformities. METHODS: Ten cases of orbital and periorbital fibrous dysplasia were treated surgically. The location, extension and shape of the lesions were identified based on X-ray examination and two and three dimensions CT examinations preoperatively. According to the type of the lesion, different approaches were used to excise the lesion and to reconstruct the orbit. The lesions were radically or partially excised through bicoronal, intraoral and subciliary approach; the orbit was reconstructed with autogenous outer or inner table of calvarium, outer table of mandible, Medpor and prefabricated individual titanic implants. RESULTS: In 10 cases treated surgically, radical excision was employed in 4 cases and partial excision in 6 cases. Autogenous inner table of calvarium was used in 2 cases, Medpor in 2 cases, outer table of mandible in 1 case, and titanic meshwork and prefabricated individual titanic implants in 4 cases to reconstruct the orbit. After the treatment, all patients obtained satisfactory aesthetic and functional results. CONCLUSIONS: Carefully planed surgical approaches with methods for preventing the complications can be used for the treatment of orbital and periorbital fibrous dysplasia and obtaining satisfactory aesthetic and functional results.
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Displasia Fibrosa Ósea/cirugía , Órbita/cirugía , Enfermedades Orbitales/cirugía , Adolescente , Adulto , Niño , Femenino , Displasia Fibrosa Ósea/diagnóstico por imagen , Humanos , Masculino , Enfermedades Orbitales/diagnóstico por imagen , Radiografía , Procedimientos de Cirugía Plástica/métodosRESUMEN
According to the Stockholm Convention, polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) are classified into unintentionally produced persistent organic pollutants (UP-POPs), and named dioxins. Coke production as a thermal process contains organic matters, metal and chlorine, is considered to be a potential source of dioxins. Intensive studies on the emission of dioxins from coking industry are still very scarce. In order to estimate the emission properties of dioxins through coke production, isotope dilution HRGC/HRMS technique was used to determine the concentration of dioxins through flue gas during heating of coal. Three results were obtained. First, total toxic equivalents at each stationary emission source were in the range of 3.9-30.0 pg x m(-3) (at WHO-TEQ) for dioxins which was lower than other thermal processes such as municipal solid waste incineration. Second, higher chlorinated PCDD/Fs were the dominant congeners. Third, emissions of dioxins were dependent on coking pattern. Stamping coking and higher coking chamber may lead to lower emission.
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Contaminantes Atmosféricos/análisis , Benzofuranos/análisis , Coque , Bifenilos Policlorados/análisis , Dibenzodioxinas Policloradas/análogos & derivados , Polímeros/análisis , China , Monitoreo del Ambiente , Incineración , Dibenzodioxinas Policloradas/análisisRESUMEN
Nanostructured materials have found increasing applications in medical therapies and diagnostics (theranostics). The main challenge is the ability to impart the nanomaterials with structurally tailored functional properties which can effectively target biomolecules but also provide signatures for effective detection. The harnessing of functional nanoparticles and assemblies serves as a powerful strategy for the creation of the structurally tailored multifunctional properties. This article highlights some of the important design strategies in recent investigation of metals (especially gold and silver), and magnetically functionalized nanoparticles, and molecularly assembled or biomolecularly conjugated nanoparticles with tunable optical, spectroscopic, magnetic, and electrical properties for applications in several areas of potential theranostic interests. Examples include colorimetric detection of amino acids and small peptides, surface-enhanced Raman scattering detection of biomolecular recognition of proteins and DNAs, delivery in cell transfection and bacteria inactivation, and chemiresistive detection of breath biomarkers. A major emphasis is placed on understanding how the control of the nanostructures and the molecular and biomolecular interactions impact these biofunctional properties, which has important implications for bottom-up designs of theranostic materials.
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Materiales Biocompatibles , Nanopartículas , Microscopía Electrónica de TransmisiónRESUMEN
Classic Raymond syndrome consists of ipsilateral abducens impairment, contralateral central facial paresis, and contralateral hemiparesis. However, subsequent clinical observations argued on the presentation of facial involvement. To validate this entity, we present a case of classic Raymond syndrome with contralateral facial paresis. A 50 year-old man experienced acute onset of horizontal diplopia, left mouth drooling and left-sided weakness. Neurological examination showed he had right abducens nerve palsy, left-sided paresis of the lower part of the face and limbs, and left hyperreflexia. A brain MRI showed a subacute infarct in the right mid-pons. The findings were consistent with those of classic Raymond syndrome. To date, only a few cases of Raymond syndrome, commonly without facial involvement, have been reported. Our case is a validation of classic Raymond syndrome with contralateral facial paresis. We propose the concept of two types of Raymond syndrome: (1) the classic type, which may be produced by a lesion in the mid-pons involving the ipsilateral abducens fascicle and undecussated corticofacial and corticospinal fibers; and (2) the common type, which may be produced by a lesion involving the ipsilateral abducens fascicle and undecussated corticospinal fibers but sparing the corticofacial fibers.
RESUMEN
OBJECTIVES: To compare the F release from glass ionomer glasses (GICs) into water changed periodically with release into an unchanged "sink" [Williams JA, Billington RW, Pearson GJ. The glass ionomer cement: the sources of soluble fluoride. Biomaterials 2002;23:2191-200]. To evaluate the effect of replacing Ca wholly or partially by Sr. To compare two different methods of decomplexing F containing species. METHODS: All four glasses contained Al, Si, P, O and F. Glass AH2 (Advanced Healthcare Ltd.) had Na and Ca, LG26 (Advanced Healthcare Ltd.) had Ca, LG26Sr (ULTRASET project) had Ca and Sr, and LG125 (ULTRASET project) had Sr. Glasses were tested: after ball-milling, after washing in dilute acid, and W mixed with 35% acetic acid to form a "pseudo-cement". F(-) release was from 130mg samples into 10ml of deionised water changed at 1, 3, 7, 14, 21, 28, 35, and 42 days. Analysis was carried out: (a) using ISE without decomplexing, (b) using TISAB buffer, and (c) acid hydrolysis+TISAB (after Hattab). RESULT: The cumulative release rates from all glasses and treatments are linear with respect to t(1/2) with r=0.97 or greater (p=<0.001). F release into a "sink" showed no such correlation. The higher release rate from AH2 is more than accounted for by its higher F content. Most F release is not complexed except of AH2. AH2 has 20% of complex fluoride from raw glass, 44% from acid-washed glass and 51% from pseudo-cement. More fluoride is released after acid treatment from all 4 glasses, these are on average 4.4 times higher from acid-washed glass and 5.3 times higher from pseudo-cement. For TISAB fluoride release, LG26Sr is 26% more than LG26. Hattab fluoride>TISAB fluoride only for raw glasses. CONCLUSIONS: Changing water produces diffusion controlled kinetics. Acid treated will increase the complex fluoride from AH2. Replacing Ca by Sr enhances F release rate slightly.