Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Filtrar
1.
Langmuir ; 34(44): 13409-13415, 2018 11 06.
Artículo en Inglés | MEDLINE | ID: mdl-30350689

RESUMEN

Directly harvesting water from the atmosphere could aid in negating the issue of fresh water scarcity, garnering increased research interest in recent years. Typically, atmospheric water collection occurs via three main steps: accumulation, transportation, and collection. Although multiple studies have been published on bioinspired structures with enhanced directional fluid transportation, there is a significant lack of designs for enhancing water droplet coalescence. Long mean times before coalescence result in the re-evaporation of microdroplets, severely impeding the efficiency of atmospheric water collection. Herein, a water accumulator derived from a synergistic combination of inspiration from cacti spines and Tillandsia trichomes has been designed to encourage rapid coalescence. The drip-off volume measured in a fog chamber was found to be 220% that of a flat surface within 15 min, suggesting that improving the coalescence efficiency will be important in the future development of water-collection devices.

2.
Pediatr Blood Cancer ; 59(3): 454-60, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22610685

RESUMEN

BACKGROUND: In 2000, the Hong Kong Pediatric Hematology Oncology Study Group started a new relapsed acute lymphoblastic leukemia (ALL) treatment protocol based on modified ALL-REZ BFM 96 protocol aiming at improving the treatment outcome in Chinese children. PROCEDURE: All patients in Hong Kong with first relapse of childhood ALL were included. Patients were stratified into four risk groups (S1, S2, S3, and S4) and the treatment consisted of intensive chemotherapy followed by allogeneic hematopoietic stem cell transplantation, if indicated. RESULTS: Fifty-six patients were recruited and median age at diagnosis of ALL was 4.6 (range, 0.3-17) years. The median time from initial diagnosis to relapse was 2.5 (range, 0.3-9.1) years and follow-up time was 2.7 (range, 0-9.9) years. Forty-nine patients (87.5%) achieved second complete remission (CR2). CR2 rates for S1, S2, S3, and S4 groups were 100%, 93%, 90%, and 67%, respectively. Five-year overall survival (OS) was 50.5 ± 6.9% and event-free survival (EFS) was 41.5 ± 7.1%. There was no significant difference in survival among S1, S2, and S3 groups but S4 patients performed significantly worse with 5-year OS and EFS of 8% and 0%, respectively. CONCLUSION: Children with relapsed ALL of S1-S3 risk groups could be successfully treated with intensified treatment protocol. The S4 high risk group needs more innovative approach to improve treatment outcome.


Asunto(s)
Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Adolescente , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Niño , Preescolar , Terapia Combinada , Supervivencia sin Enfermedad , Femenino , Trasplante de Células Madre Hematopoyéticas , Hong Kong , Humanos , Lactante , Masculino , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidad , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , Pronóstico , Recurrencia , Inducción de Remisión , Factores de Riesgo , Resultado del Tratamiento
3.
Environ Sci Technol ; 46(20): 11078-85, 2012 Oct 16.
Artículo en Inglés | MEDLINE | ID: mdl-22985332

RESUMEN

Whereas the oxidation of inorganic Fe(II) by H(2)O(2) in seawater has been well studied, the oxidation of Fe(II) complexes with natural organic matter (NOM) by this ubiquitous oxidant has received little attention. Suwannee River fulvic acid (SRFA), a proxy for terrestrial NOM, is shown to have a much smaller impact upon Fe(II) oxidation kinetics in seawater than the strong effect previously observed in freshwater conditions. However, the oxidation kinetics of Fe(II) in seawater and freshwater can be quantitatively described employing the same mechanistic kinetic model, except that the apparent formation constant of Fe(II)-SRFA complexes is substantially decreased under conditions representative of estuarine and river-influenced coastal waters. This implies that the same basic processes occur in both systems, with differences between Fe(II) oxidation kinetics in seawater and freshwater largely attributable to effects of ionic strength and matrix composition. This was confirmed with studies employing NaCl solutions with or without Mg(2+)/Ca(2+) addition demonstrating that both ionic strength and divalent cations effect a decrease in the Fe(II)-binding affinity of SRFA. The impact of NOM upon iron redox transformation kinetics is therefore greatly influenced by changes in both ionic strength and the presence of cations able to compete with Fe(II) for binding sites.


Asunto(s)
Benzopiranos/química , Peróxido de Hidrógeno/química , Agua de Mar/química , Contaminantes Químicos del Agua/química , Calcio/química , Agua Dulce/química , Cinética , Manganeso/química , Modelos Químicos , Oxidación-Reducción , Salinidad , Cloruro de Sodio/química
4.
Int J Adv Manuf Technol ; 119(1-2): 3-40, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-34720326

RESUMEN

This paper reviews recent progress and applications of usage of cutting fluids in conventional machining processes. In addition to reviewing the various conventional and advanced cooling techniques during machining, the paper also discusses the use of minimum quantity lubrication (MQL) in several types on metals such as steel, aluminum, alloy, and titanium alloys. Due to the toxicity of conventional cutting fluid resulting in ecological problems, the demand for environmentally friendly cutting fluid is rising. Therefore, natural vegetable oil is chosen as potential replacement as an environmentally friendly cutting fluid which fulfills the important aspects of biodegradability and sustainability. Application of vegetable oil-based cutting fluids under MQL techniques are also discussed. Moreover, the potential of palm oil as biodegradable and environmentally friendly natural vegetable oil-based metal-working fluids in MQL are reviewed.

5.
ACS Appl Mater Interfaces ; 12(15): 17659-17668, 2020 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-32202755

RESUMEN

Electrolyte solutions and electrode active materials, as core components of energy storage devices, have a great impact on the overall performance. Currently, supercapacitors suffer from the drawbacks of low energy density and poor cyclic stability in typical alkaline aqueous electrolytes. Herein, the ultrathin Co3O4 anode material is synthesized by a facile electrodeposition, followed by postheat treatment process. It is found that the decomposition of active materials induces reduction of energy density and specific capacitance during electrochemical testing. Therefore, a new strategy of preadding Co2+ cations to achieve the dissolution equilibrium of cobalt in active materials is proposed, which can improve the cyclic lifetime of electrode materials and broaden the operation window of electrochemical devices. Co2+ and Li+ embedded in carbon electrode during charging can enhance H+ desorption energy barrier, further hampering the critical step of bulk water electrolysis. More importantly, the highly reversible chemical conversion mechanism between Co3O4 and protons is demonstrated to be the fact that a large amount of quantum dots and second-order flaky CoO layers were in situ formed in the electrochemical reaction process, which is first discovered and reported in neutral solutions. The as-assembled device achieves a high operation voltage (2.2 V), excellent cycling stability (capacitance retention of 168% after 10 000 cycles) and ultrahigh energy density (99 W h kg-1 at a power density of 1100 W kg-1). The as-prepared electrolytes and highly active electrode materials will open up new opportunities for aqueous supercapacitors with high safety, high voltage, high energy density, and long-lifespan.

6.
Chinese Medical Journal ; (24): 3686-3692, 2011.
Artículo en Inglés | WPRIM | ID: wpr-273991

RESUMEN

<p><b>BACKGROUND</b>Childhood cancer survivors were at risk of development of second malignant neoplasms. The aim of this study is to evaluate the incidence, risk factors and outcome of second malignant neoplasms in childhood cancer survivors in a tertiary paediatric oncology centre in Hong Kong, China.</p><p><b>METHODS</b>We performed a retrospective review of patients with childhood cancer treated in Children's Cancer Centre in Prince of Wales Hospital, Hong Kong, China between May 1984 and June 2009. Case records of patients who developed second malignant neoplasms were reviewed.</p><p><b>RESULTS</b>Totally 1374 new cases aged less than 21-year old were treated in our centre in this 25-year study period. Twelve cases developed second malignant neoplasms with 10-year and 20-year cumulative incidence of 1.3% (95% confidence interval 0.3% - 2.3%) and 2.9% (95% confidence interval 1.1% - 4.7%) respectively. Another 4 cases were referred to us from other centres for the management of second malignant neoplasms. In this cohort of 16 children with second malignant neoplasms, the most frequent second malignant neoplasms were acute leukemia or myelodysplastic syndrome (n = 6) and central nervous system tumor (n = 4). Median interval between diagnosis of primary and second malignant neoplasms was 7.4 years (range 2.1 - 13.3 years). Eight patients developed second solid tumor within the previous irradiated field. Radiotherapy significantly increased the risk of development of second solid tumor in patients with acute lymphoblastic leukemia (P = 0.027). Seven out of 16 patients who developed second malignant neoplasms had a family history of cancer among the first or second-degree relatives. Nine patients died of progression of second malignant neoplasms, mainly resulted from second central nervous system tumor and osteosarcoma.</p><p><b>CONCLUSIONS</b>Cumulative incidence of second cancer in our centre was comparable to western countries. Radiotherapy was associated with second solid tumour among patients with acute lymphoblastic leukemia. Patients who developed second brain tumor and osteosarcoma had a poor outcome.</p>


Asunto(s)
Adolescente , Adulto , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Adulto Joven , China , Epidemiología , Hong Kong , Epidemiología , Neoplasias , Epidemiología , Neoplasias Primarias Secundarias , Epidemiología , Leucemia-Linfoma Linfoblástico de Células Precursoras , Estudios Retrospectivos , Sobrevivientes
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA