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1.
Environ Sci Pollut Res Int ; 30(60): 125965-125976, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38008831

RESUMO

The main aim of this study is to investigate the material and monetary flows of CDW management and to characterize the distribution of illegally dumped CDW in Hanoi. Construction and demolition waste management has become a source of much concern to the urban authorities and citizens of big cities in Vietnam. It is estimated that 3000 t of CDW were generated per day from construction and demolition activities in Hanoi, but only 45% of the CDW was received at official landfills, while 55% of the CDW was disposed of elsewhere. The consequences of improper waste management are potentially alarming. The study conducted interviews to identify the material and cash flow associated with licensed and unlicensed contractors in CDW classification, transportation, treatment, and disposal, to characterize the distribution of illegally dumped CDW in two districts in Hanoi (urban and suburban districts), and to assess the composition of dumped CDW and environmental assessment of illegally dumped CDW by chemical analyses such as leaching and content tests. The study concluded that illegal dumping was performed mostly by unlicensed private companies. The illegally dumped CDW was mostly composed of mixed materials such as concrete, bricks, stones, and some hazardous materials such as asbestos and gypsum were found. The environmental concern of illegally dumped CDW was mostly dust, blockage of water ways, and inundation of increased suspended solids, whereas the heavy metal leaching concentration of all samples was below the environmental standards in Vietnam.


Assuntos
Indústria da Construção , Metais Pesados , Gerenciamento de Resíduos , Materiais de Construção/análise , Instalações de Eliminação de Resíduos , Metais Pesados/análise , Reciclagem , Resíduos Industriais/análise
2.
Nat Nanotechnol ; 18(3): 273-280, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36624206

RESUMO

Block copolymer self-assembly is a powerful tool for two-dimensional nanofabrication; however, the extension of this self-assembly concept to complex three-dimensional network structures is limited. Here we report a simple method to experimentally generate three-dimensional layered mesh morphologies through intrinsic molecular confinement self-assembly. We designed triblock bottlebrush polymers with two Janus domains: one perpendicular and one parallel to the polymer backbone. The former enforces a lamellar superstructure that intrinsically confines the intralayer self-assembly of the latter, giving rise to a mesh-like monoclinic (54°) M15 network substructure with excellent long-range order, as well as a tetragonal (90°) T131 mesh. Numerical simulations show that the spatial constraints exerted on the polymer backbone drive the assembly of M15 and yield T131 in the strong segregation regime. This work demonstrates that intrinsic molecular confinement is a viable path to bottom-up assembly of new geometrical phases of soft matter, extending the capabilities of block copolymer nanofabrication.

3.
Waste Manag ; 149: 218-227, 2022 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-35752109

RESUMO

In Vietnam, an increase in construction activities together with the absence of recycling-oriented demolition techniques is giving rise to an alarming generation of construction and demolition waste. This study scrutinized the current state of building demolition approaches in Hanoi, Vietnam and evaluated the potential for the selective dismantling, or deconstruction, of reinforced-concrete (RC) houses. Site observations, direct measurement, and interviews were conducted to obtain information on technical, environmental, and economic characteristics of three residential housing sites, each representing a typical current demolition technique (manual, hybrid, and mechanical demolition). A selective dismantling site is proposed based on the collected survey data and published case studies. Our findings confirmed the unsustainability of RC-building demolition practices in Hanoi, which have an average reuse/recycling rate of roughly 3%. The application of selective dismantling will boost the recycling rate to a remarkable 90%, associated with a 55% decrease in greenhouse gas emissions. Even though selective dismantling is more time-consuming and therefore more costly, it results in double the resale value and an eight-fold decrease in disposal costs. The results of a sensitivity analysis indicate that increasing the current disposal fee will significantly improve the feasibility of selective dismantling, suggesting a need for stricter disposal charging mechanisms along with other interventions such as the development of recycling facilities to promote the introduction of this building removal alternative in Vietnam.


Assuntos
Indústria da Construção , Gerenciamento de Resíduos , Indústria da Construção/métodos , Materiais de Construção , Resíduos Industriais/análise , Reciclagem , Vietnã
4.
Acute Med Surg ; 9(1): e733, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35169486

RESUMO

BACKGROUND: Small bowel bleeding is an uncommon cause of lower gastrointestinal bleeding, which may require different management. CASE PRESENTATION: A 37-year-old man presenting with hematochezia was promptly diagnosed with small bowel bleeding by computed tomography angiography. Transcatheter arterial embolization was carried out because the patient's hemodynamic status deteriorated. Hemostasis was achieved by embolization with imipenem/cilastatin, although superselective embolization failed. Capsule endoscopy revealed multiple ulcers and erosions. Drug-induced small bowel injury was suspected to be the cause of small bowel bleeding. CONCLUSION: Computed tomography angiography can facilitate the management of lower gastrointestinal bleeding. Considering transcatheter arterial embolization and choosing an optimal embolic agent depending on the situation are important in the management of hemodynamically unstable patients.

5.
Sci Rep ; 11(1): 20647, 2021 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-34667265

RESUMO

The fovea is a depression in the center of the macula and is the site of the highest visual acuity. Optical coherence tomography (OCT) has contributed considerably in elucidating the pathologic changes in the fovea and is now being considered as an accompanying imaging method in drug development, such as antivascular endothelial growth factor and its safety profiling. Because animal numbers are limited in preclinical studies and automatized image evaluation tools have not yet been routinely employed, essential reference data describing the morphologic variations in macular thickness in laboratory cynomolgus monkeys are sparse to nonexistent. A hybrid machine learning algorithm was applied for automated OCT image processing and measurements of central retina thickness and surface area values. Morphological variations and the effects of sex and geographical origin were determined. Based on our findings, the fovea parameters are specific to the geographic origin. Despite morphological similarities among cynomolgus monkeys, considerable variations in the foveolar contour, even within the same species but from different geographic origins, were found. The results of the reference database show that not only the entire retinal thickness, but also the macular subfields, should be considered when designing preclinical studies and in the interpretation of foveal data.


Assuntos
Degeneração Macular/diagnóstico por imagem , Tomografia de Coerência Óptica/métodos , Algoritmos , Animais , Retinopatia Diabética/patologia , Processamento de Imagem Assistida por Computador , Macaca fascicularis , Aprendizado de Máquina , Degeneração Macular/genética , Degeneração Macular/patologia , Retina/patologia , Acuidade Visual
6.
Waste Manag ; 131: 294-304, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-34198183

RESUMO

Increasing waste generation and the absence of a formal recycling industry are exacerbating the inadequacy of Construction and Demolition Waste (CDW) management in Hanoi, Vietnam. This study assesses potential CDW recycling in Hanoi by estimating the prospective supply of and demand for CDW recycling plants and evaluating their likely costs and benefits. Supply of concrete waste was calculated based on the weight-per-construction-area method whilst demand for recycled concrete aggregates (RCA) was determined by estimating the amount of aggregates for road construction in Hanoi from 2013 to 2017. Two potential models of CDW recycling plants were considered: a stationary plant and a mobile plant, with capacities of 1,000 and 360 tons/day, respectively. Our findings reveal that demand for RCA exceeds waste concrete supply, suggesting a promising market for RCA. Positive Net Present Value and Internal Rate of Return values of the stationary plant indicate its feasibility as an investment option. Meanwhile, the introduction of mobile recycling plants might require governmental intervention to internalize recycling positive externalities. Supporting policies might include a combination of a virgin material tax, green public procurement, and quality standard development.


Assuntos
Indústria da Construção , Gerenciamento de Resíduos , Materiais de Construção , Análise Custo-Benefício , Resíduos Industriais/análise , Estudos Prospectivos , Reciclagem , Vietnã
8.
Asia Pac J Ophthalmol (Phila) ; 10(4): 350-354, 2021 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-33606386

RESUMO

PURPOSE: There is a need for a simple and accurate way to assess visual acuity in telemedicine consultations in ophthalmology and other related specialties. DESIGN: We surveyed visual acuity testing apps available that allow patients to measure their own acuity, focusing on freely accessible resources suitable for all resource settings. METHODS: A systematic search was performed for visual acuity testing apps on 2 major platforms: Google Play Store (Google, CA, USA) and Apple App Store (Apple, CA, USA). RESULTS: Sixteen apps (67%) tested near vision, 5 apps (21%) tested distance vision, and 3 apps (13%) offered options for both near and distance vision testing. Of the 24 apps, 5 (21%) offered a method of calibration of optotype size. Three apps (13%) demonstrated evidence of clinical validation. Only 3 apps fulfilled our criteria for suitability for clinical practice. CONCLUSIONS: We have recommended 3 apps that may be quickly integrated into clinical practice in both ophthalmic and non-ophthalmic all resource settings.


Assuntos
Oftalmologia , Consulta Remota , Acuidade Visual , Humanos , Aplicativos Móveis
9.
Waste Manag ; 117: 32-41, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32805599

RESUMO

This study conducted a survey at 15 building construction and demolition sites in Hanoi, Vietnam in order to identify waste generation rates (WGR), composition, and current handling practices of construction and demolition waste (CDW). Waste quantification based on CDW layout, image analysis to identify CDW components, and face-to-face interviews with construction and demolition contractors to reveal CDW flows were performed. WGRs of 79.3 kg/m2 and 1,030 kg/m2 were determined in small- and large-scale construction sites, respectively, whilst WGRs at small and large demolition sites were 610 kg/m2 and 318 kg/m2. The composition analysis identified soil, concrete, and brick as the major CDW components, consistent with building structures in Vietnam. The interviews discovered that merely 10% of total CDW flows was from recycled and reused CDW. Reuse and recycling rates were most significant for metal and were lower (in descending order) for brick, concrete, and soil. These findings raise a need for aggressive and integrated strategies to promote more sustainable CDW management in the country, including the development of recycled CDW product standards, policies that facilitate recycling, and more importantly, a sustainable business model for CDW recycling, for which future evaluations of economic feasibility are of great importance.


Assuntos
Indústria da Construção , Gerenciamento de Resíduos , Materiais de Construção , Resíduos Industriais/análise , Reciclagem , Vietnã
10.
Sci Total Environ ; 722: 137783, 2020 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-32208245

RESUMO

Groundwater is essential for the Earth biosphere but is often contaminated by harmful chemical compounds due to both anthropogenic and natural causes. A key factor controlling the fate of harmful chemicals in groundwater is the reduction/oxidation (redox) conditions. The formation factors for the groundwater redox conditions are insufficiently understood. In this study, long-term groundwater quality beneath one of the world megacities was monitored and evaluated. We measured and compared hydrogeochemical conditions including groundwater quality (35 chemical parameters) and redox conditions of five aquifers in the Arakawa Lowland and Musashino Upland, southern Kanto Plain of the Tokyo Metropolitan area, Japan. Monitoring results suggested the following: The main origin of groundwater is precipitation in both the Lowland and Upland areas. The three aquifers in the Arakawa Lowland are likely fully separated, with one unconfined and two confined aquifers under iron reducing and methanogenic conditions, respectively. Oppositely, in the Musashino Upland, the water masses in the two aquifers are likely partly connected, under aerobic conditions, and undergoing the same groundwater recharge and flow processes under similar hydrogeological conditions. The different groundwater redox conditions observed are likely caused by the very different groundwater residence times for the Arakawa Lowland and Musashino Upland.

11.
Vasc Endovascular Surg ; 53(2): 139-144, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30466376

RESUMO

INTRODUCTION:: Aortic mural thrombosis associated with a malignant disease is rare, and whether anticoagulation therapy or surgical treatment is the more definitive primary treatment remains uncertain. This study aims to determine the best treatment strategy for aortic thrombosis in a patient with a malignant disease. METHODS:: We reviewed medical literature using the PubMed database and present a case of aortic thrombosis due to a hypercoagulable state related to sigmoid colon adenocarcinoma. RESULTS:: Of the 18 patients from 14 articles included in this study, 13 received simple anticoagulation as a primary treatment (anticoagulation group), while 5 underwent surgical treatment (surgical treatment group). Recurrence or exacerbation of embolism was found in 2 (15.4%) of the 13 patients and in 1 (20.0%) of the 5 patients ( P = 1.0). Major complications were observed in 1 (7.7%) of the patients in the anticoagulation group and in 1 (20.0%) of the 5 patients in the surgical treatment group ( P = .49). No significant differences between the groups were found. CONCLUSIONS:: A simple anticoagulation therapy may be as effective as surgical treatment in patients with aortic thrombosis associated with malignancy.


Assuntos
Adenocarcinoma/complicações , Doenças da Aorta/etiologia , Neoplasias do Colo Sigmoide/complicações , Trombose/etiologia , Adenocarcinoma/sangue , Adenocarcinoma/diagnóstico , Anticoagulantes/administração & dosagem , Doenças da Aorta/diagnóstico por imagem , Doenças da Aorta/tratamento farmacológico , Aortografia/métodos , Angiografia por Tomografia Computadorizada , Feminino , Fibrinolíticos/administração & dosagem , Heparina/administração & dosagem , Humanos , Pessoa de Meia-Idade , Neoplasias do Colo Sigmoide/sangue , Neoplasias do Colo Sigmoide/diagnóstico , Trombose/diagnóstico por imagem , Trombose/tratamento farmacológico , Resultado do Tratamento
12.
ACS Macro Lett ; 7(4): 472-476, 2018 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30271675

RESUMO

The polymerization of functional monomers provides direct access to functional polymers without need for postpolymerization modification; however, monomer synthesis can become a bottleneck of this approach. New methods that enable rapid installation of functionality into monomers for living polymerization are valuable. Here, we report the three-step convergent synthesis (two-step longest linear sequence) of a divalent exo-norbornene imide capable of efficient coupling with various nucleophiles and azides to produce diversely functionalized branched macromonomers optimized for ring-opening metathesis polymerization (ROMP). In addition, we describe an efficient iterative procedure for the synthesis of tri-and tetra-valent branched macromonomers. We demonstrate the use of these branched macromonomers for the synthesis of Janus bottlebrush block copolymers as well as for the generation of bottlebrush polymers with up to three conjugated small molecules per repeat unit. This work significantly expands the scalability and diversity of nanostructured macromolecules accessible via ROMP.

13.
Int J Surg Case Rep ; 50: 97-99, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30096534

RESUMO

INTRODUCTION: Reduction en masse is a rare complication of inguinal hernia. This condition is defined as the displacement of a strangulated hernia mass into the preperitoneal space. CASE PRESENTATION: A 62-year-old man presented with severe abdominal pain after a forcible reduction of an incarcerated right inguinal hernia. Abdominal computed tomography (CT) scan suggested strangulated bowel. Emergency exploratory laparoscopy was performed and the incarcerated bowel was successfully released. Elective preperitoneal inguinal hernia repair using the Modified Kugel™ Patch was performed under laparoscopic guidance. The patient made an uneventful recovery. DISCUSSION: Reduction en masse should be considered when abdominal pain persists after a difficult reduction of inguinal hernia. Laparoscopic guidance led to the definitive repair of the inguinal hernia with reduction en masse. CONCLUSION: Laparoscopic relief can be an efficient therapeutic option for the management of this condition. In addition, Modified Kugel™ Patch repair with ligation of the hernia sac could be a reasonable treatment.

14.
Environ Sci Pollut Res Int ; 25(24): 24500-24506, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30009359

RESUMO

Landfill sites are significant sources of methane gas globally. Understanding the temporal variabilities of methane emissions from landfill sites is necessary for estimating such emissions. In this study, an automated monitoring system was used to monitor methane emission flux and concentration on daily and hourly time scales at a landfill site. Measured methane emission fluxes were almost negligible in the studied area. However, methane concentration at landfill surface at nighttime was significantly higher than those in the daytime, which demonstrates the importance of investigating methane emissions at an hourly time scale, including during nighttime. The daily and hourly variations in methane concentration were well correlated with either soil temperature or volumetric water content near the surface. The obtained relations indicate that the automated monitoring system measurements can facilitate a more comprehensive understanding of the methane emission mechanisms at different time scales.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Metano/análise , Instalações de Eliminação de Resíduos , Monitoramento Ambiental/instrumentação , Japão , Eliminação de Resíduos , Solo/química , Fatores de Tempo , Água/análise
15.
Nano Lett ; 18(7): 4360-4369, 2018 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-29877712

RESUMO

The self-assembly of block copolymers (BCPs) with novel architectures offers tremendous opportunities in nanoscale patterning and fabrication. Here, the thin film morphology, annealing kinetics, and topographical templating of an unconventional Janus-type "PS- branch-PDMS" bottlebrush copolymer (BBCP) are described. In the Janus-type BBCP, each segment of the bottlebrush backbone connects two immiscible side chain blocks. Thin films of a Janus-type BBCP with Mn = 609 kg/mol exhibited 22 nm period cylindrical microdomains with long-range order under solvent vapor annealing, and the effects of as-cast film thickness, solvent vapor pressure, and composition of the binary mixture of solvent vapors are described. The dynamic self-assembly process was characterized using in situ grazing-incidence X-ray scattering. Templated self-assembly of the BBCP within lithographically patterned substrates was demonstrated, showing distinct pattern orientation and dimensions that differ from conventional BCPs. Self-consistent field theory is used to elucidate details of the templated self-assembly behavior within confinement.

16.
Proc Natl Acad Sci U S A ; 114(19): 4875-4880, 2017 05 09.
Artigo em Inglês | MEDLINE | ID: mdl-28439017

RESUMO

Controlling the molecular structure of amorphous cross-linked polymeric materials is a longstanding challenge. Herein, we disclose a general strategy for precise tuning of loop defects in covalent polymer gel networks. This "loop control" is achieved through a simple semibatch monomer addition protocol that can be applied to a broad range of network-forming reactions. By controlling loop defects, we demonstrate that with the same set of material precursors it is possible to tune and in several cases substantially improve network connectivity and mechanical properties (e.g., ∼600% increase in shear storage modulus). We believe that the concept of loop control via continuous reagent addition could find broad application in the synthesis of academically and industrially important cross-linked polymeric materials, such as resins and gels.

17.
Int J Surg Case Rep ; 29: 245-248, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27923206

RESUMO

INTRODUCTION: Nonocclusive mesenteric ischemia (NOMI) has been reported to be associated with high mortality. Early diagnosis of NOMI and prompt restoration of the intestinal blood flow is necessary in order to achieve a favorable outcome. PRESENTATION OF CASE: We present the case of a patient who developed NOMI after autologous blood collection and was treated by selective infusion of the superior mesenteric artery with papaverine, intestinal decompression using a long intestinal tube, the administration of antibiotics, and fluid replacement. Although this non-surgical management was successful, 8 weeks after the ischemic event, segmental bowel resection was necessary because of repeated intestinal obstruction caused by bowel stricture. DISCUSSION: Autologous blood collection might be a risk factor of NOMI. In addition, the possibility of delayed intestinal stenosis remains, even if bowel necrosis and surgical resection were avoided with non-surgical management including vasodilator therapy. CONCLUSION: Rapid diagnosis and intervention are essential to minimize intestinal ischemia.

18.
Science ; 353(6305): 1264-8, 2016 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-27634530

RESUMO

Elasticity, one of the most important properties of a soft material, is difficult to quantify in polymer networks because of the presence of topological molecular defects in these materials. Furthermore, the impact of these defects on bulk elasticity is unknown. We used rheology, disassembly spectrometry, and simulations to measure the shear elastic modulus and count the numbers of topological "loop" defects of various order in a series of polymer hydrogels, and then used these data to evaluate the classical phantom and affine network theories of elasticity. The results led to a real elastic network theory (RENT) that describes how loop defects affect bulk elasticity. Given knowledge of the loop fractions, RENT provides predictions of the shear elastic modulus that are consistent with experimental observations.

19.
J Am Chem Soc ; 138(36): 11501-4, 2016 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-27580971

RESUMO

We report the synthesis of Janus bottlebrush block copolymers by graft-through polymerization of branched diblock macromonomers. Self-assembly of the bottlebrushes was characterized by small-angle X-ray scattering, atomic force microscopy, and scanning electron microscopy. Phase separation and packing models of the bottlebrushes were computed, and their self-assembly behavior was corroborated experimentally in bulk and in thin films. Lamellar, hexagonal cylinder, and gyroid phases were observed and modeled. The A-branch-B Janus bottlebrush structure provides several unique advantages in the context of bottlebrush polymer assembly, including access to the first examples of gyroid phases.


Assuntos
Polímeros/química , Polímeros/síntese química , Técnicas de Química Sintética , Modelos Moleculares , Conformação Molecular , Polimerização
20.
J Air Waste Manag Assoc ; 66(12): 1257-1267, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27575846

RESUMO

A long-term monitoring of composition of landfill gases in the region with high rainfall was conducted using an argon assay in order to discuss air intrusion into the dump site. Gas samples were taken from vertical gas monitoring pipes installed along transects at two sections (called new and old) of an abandoned waste dump site in Sri Lanka. N2O concentrations varied especially widely, by more than three orders of magnitude (0.046-140 ppmv). The nitrogen/argon ratio of landfill gas was normally higher than that of fresh air, implying that denitrification occurred in the dump site. Argon assays indicate that both N2 and N2O production occurred inside waste and more significantly in the old section. The Ar assay would help for evaluations of N2O emission in developing countries. IMPLICATIONS: A long-term monitoring of composition of landfill gases in the region with high rainfall was conducted using an argon assay in order to discuss air intrusion into the dump site. Argon assays indicate that both N2 and N2O production occurred inside waste and more significantly in the old section.


Assuntos
Poluentes Atmosféricos/análise , Eliminação de Resíduos , Resíduos Sólidos/análise , Instalações de Eliminação de Resíduos , Monitoramento Ambiental/métodos , Gases/análise , Nitrogênio/análise , Óxido Nitroso/análise , Sri Lanka , Fatores de Tempo
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