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1.
Sci Total Environ ; 713: 136573, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-31955087

RESUMO

Lignin is a highly complex, plant-derived natural biomass component, the analysis of which requires significant demands on the analytical platform. Fourier transform ion cyclotron mass spectrometry (FT-ICR MS) has been shown to be able to readily assess the complexity of lignin and lignin degradation products by assigning tens of thousands of compounds with elemental formulae. Nevertheless, many experimental and instrumental parameters introduce discrimination towards certain components, which limits the comprehensive MS analysis. As a result, a complete characterization of the lignome remains a challenge. The present study investigated a degraded lignin sample using FT-ICR MS and compared several atmospheric pressure ionization methods, e.g., electrospray ionization, atmospheric-pressure chemical ionization, and atmospheric-pressure photoionization. The results clearly show that the number of heteroatoms (e.g., N, S, P) in the sample greatly increases the chemical diversity of lignin, while at the same time also providing potentially useful biomarkers. We demonstrate here that FT-ICR MS was able to directly isolate isotopically pure single components from the ultra-complex mixture for subsequent structural analysis, without the time-consuming chromatographic separation. CAPSULE: Various ionization techniques coupled to FT-ICR MS provide a powerful tool to assess the lignome coverage.


Assuntos
Pressão Atmosférica , Lignina/química , Análise de Fourier , Íons , Espectrometria de Massas
2.
Diving Hyperb Med ; 49(4): 276-282, 2019 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-31828746

RESUMO

INTRODUCTION: When humans breathe compressed air or N2-O2 mixtures at three to four atmospheres pressure, they will experience nitrogen narcosis that may possibly lead to a diving accident, but the underlying mechanisms remain unclear. METHODS: Mice were exposed to 1.6 MPa breathing a N2-O2 mixture adjusted to deliver an inspired PO2 of 32-42 kPa. The electroencephalogram (EEG) and forced swimming test were used to evaluate the narcotic effect of nitrogen. Neuronal activity was observed via c-Fos expression in cortex and hippocampus tissue after decompressing to the surface. To further investigate underlying molecular mechanisms, we incubated cultured hippocampal neurons with various NMDA concentrations, and measured expression of NMDA receptors and its down-stream signal with or without 1.6 MPa N2-O2 exposure. RESULTS: Both the frequency of the EEG and the drowning time using the forced swimming test were significantly decreased during exposure to 1.6 MPa N2-O2 (P < 0.001). Additionally, in cultured hippocampal neurons, the increased levels of phosphorylated NR2B and cAMP-response element binding protein (CREB) induced by NMDA stimulation were significantly inhibited by exposure to 1.6 MPa N2-O2. CONCLUSIONS: Our findings indicated that NR2B-containing NMDA receptors were inhibited during nitrogen narcosis.


Assuntos
Pressão Atmosférica , Mergulho , Narcose por Gás Inerte , Nitrogênio/metabolismo , Receptores de N-Metil-D-Aspartato , Animais , Córtex Cerebelar/metabolismo , Eletroencefalografia , Hipocampo/metabolismo , Humanos , Narcose por Gás Inerte/patologia , Camundongos , Neurônios/fisiologia , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Receptores de N-Metil-D-Aspartato/metabolismo
3.
Undersea Hyperb Med ; 46(5): 619-623, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31683359

RESUMO

Objective: Scuba diving and freediving are popular activities around the world, and their growth has increased the frequency of related pathology. A good ability to equalize is of paramount importance for diving. This is especially true for freediving, during which dive time is limited to just one breath. Even though equalization disorders are quite common in divers, a scoring system does not exist to date. In this paper we propose a new scoring system for equalization problems of freedivers: the EP score, shorthand for "equalization problems." Methods: We administered the EP score assessment to 40 Italian freediving spearfishermen who were divided in two groups: Group A comprised 20 freedivers complaining of equalization problems and multiple barotraumas but totally asymptomatic in their everyday lives. These individuals had already received medical treatment and nasal surgery without improvement and then had undergone Eustachian tube balloon dilation. Group B comprised 20 healthy freedivers without any history of equalization disorders. We performed a statistical analysis to evaluate the reliability of this scoring system and to evaluate its usefulness in diagnosis and follow-up. Results: Our data show substantial statistical differences between healthy freedivers and freedivers complaining of equalization disorders (Z-Score = -5.396 at p ⟨ 0.05); data do not show any statistical difference between healthy freedivers and patients successfully treated by Eustachian tube balloon dilation (U-value = 152.5 and Z-Score= -1.271 at p ⟨ 0.05). Conclusion: The EP score assessment seems to be a reliable tool to quantify equalization disorders during freediving and to evaluate how the difficulty varies over time and after treatment. Since equalization disorders could be present in different populations, the EP score assessment could be applicable to a wider group.


Assuntos
Suspensão da Respiração , Mergulho/fisiologia , Otopatias/diagnóstico , Orelha Média/fisiologia , Tuba Auditiva , Adulto , Pressão Atmosférica , Barotrauma/etiologia , Barotrauma/prevenção & controle , Dilatação , Otopatias/etiologia , Otopatias/terapia , Tuba Auditiva/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Estatísticas não Paramétricas , Inquéritos e Questionários , Adulto Jovem
4.
Undersea Hyperb Med ; 46(5): 665-672, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31683366

RESUMO

We compared the efficacy of hyperbaric oxygen (HBO2) therapy used in the treatment of sudden sensorineural hearing loss (SSNHL) as a supplementary therapy to the first-line medical treatment according to the different applied pressures used in HBO2 treatment while maintaining the same number of sessions, periodicity and exposure times. We evaluated data from 115 patients suffering from SSNHL within seven days of hearing loss: 35 patients received the standard treatment protocol (control group), and 80 individuals were treated with additional application of HBO2 therapy pressured to 2.0 ATA (H2.0; n=49) or 2.5 ATA (H2.5; n=31), respectively. Treatment success was assessed using pre- and post-treatment audiograms. We found significant differences in both HBO2 groups compared to the control group. In low frequencies the most significant differences can be seen in both H2.0 and H2.5. In spoken speech frequencies only the H2.0 group was statistically significant. In high frequencies the therapeutic benefits were the lowest. Furthermore, we found a notable difference in the therapeutic effect of HBO2 therapy according to the different applied pressure. At low frequencies, the use of 2.5 ATA pressure was more efficient. However, in the higher frequency ranges, the better hearing gains were obtained at the 2.0 ATA pressure. Our results support the possibility of optimizing treatments individually, depending on the type and frequency range of hearing impairment (shape of the audiogram) in favor of using the 2.0 ATA. This is important in terms of an individual approach to each patient as well as to minimize the burden of a patient in order to obtain the maximum therapeutic effect.


Assuntos
Perda Auditiva Neurossensorial/terapia , Perda Auditiva Súbita/terapia , Oxigenação Hiperbárica/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Pressão Atmosférica , Estudos de Casos e Controles , Feminino , Glucocorticoides/administração & dosagem , Perda Auditiva Neurossensorial/tratamento farmacológico , Perda Auditiva Súbita/tratamento farmacológico , Humanos , Masculino , Hemissuccinato de Metilprednisolona/administração & dosagem , Pessoa de Meia-Idade , Prednisona/administração & dosagem , Estudos Prospectivos , Adulto Jovem
5.
Undersea Hyperb Med ; 46(5): 673-683, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31683367

RESUMO

Gas can enter arteries (arterial gas embolism, AGE) due to alveolar-capillary disruption (caused by pulmonary over-pressurization, e.g. breath-hold ascent by divers) or veins (venous gas embolism, VGE) as a result of tissue bubble formation due to decompression (diving, altitude exposure) or during certain surgical procedures where capillary hydrostatic pressure at the incision site is subatmospheric. Both AGE and VGE can be caused by iatrogenic gas injection. AGE usually produces stroke-like manifestations, such as impaired consciousness, confusion, seizures and focal neurological deficits. Small amounts of VGE are often tolerated due to filtration by pulmonary capillaries; however VGE can cause pulmonary edema, cardiac "vapor lock" and AGE due to transpulmonary passage or right-to-left shunt through a patient foramen ovale. Intravascular gas can cause arterial obstruction or endothelial damage and secondary vasospasm and capillary leak. Vascular gas is frequently not visible with radiographic imaging, which should not be used to exclude the diagnosis of AGE. Isolated VGE usually requires no treatment; AGE treatment is similar to decompression sickness (DCS), with first aid oxygen then hyperbaric oxygen. Although cerebral AGE (CAGE) often causes intracranial hypertension, animal studies have failed to demonstrate a benefit of induced hypocapnia. An evidence based review of adjunctive therapies is presented.


Assuntos
Embolia Aérea/terapia , Oxigenação Hiperbárica/métodos , Algoritmos , Altitude , Artérias , Pressão Atmosférica , Descompressão/efeitos adversos , Doença da Descompressão/complicações , Mergulho/efeitos adversos , Embolia Aérea/diagnóstico , Embolia Aérea/etiologia , Forame Oval Patente/complicações , Humanos , Embolia Intracraniana/etiologia , Embolia Intracraniana/terapia , Posicionamento do Paciente/métodos , Veias
7.
J Oral Sci ; 61(4): 521-525, 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31588099

RESUMO

Oral diseases generally have certain bacteria associated with them. Non-thermal atmospheric pressure plasma (NTAP), generated at atmospheric pressure and room temperature, incorporates several molecules, including reactive oxygen species, that can inactivate various bacteria including oral pathogens. For this reason, several NTAP devices have been developed to treat oral diseases. Use of noble gases can enhance the bactericidal efficacy of NTAP, but this requires additional gas supply equipment. Therefore, a new NTAP device that employs ambient air as the working gas was developed. The device generates non-thermal atmospheric pressure air plasma. Here, the singlet oxygen (1O2) levels generated, their bactericidal effects on oral pathogens (Streptococcus mutans, Porphyromonas gingivalis, and Enterococcus faecalis), and the bacterial oxidative stress they imposed were measured. 1O2 generation in phosphatebuffered saline was assessed qualitatively using electron spin resonance (ESR) spectroscopy, and bactericidal efficacy was evaluated by counting of colony-forming units/mL. Bacterial oxidative stress was determined by measurement of hydrogen peroxide (H2O2) and superoxide dismutase (SOD) activity. ESR indicated that the level of 1O2 increased significantly and time-dependently, and was inversely correlated with distance, but the bactericidal effects were correlated only with treatment time (not distance) as H2O2 increased and SOD levels decreased, suggesting that the new device has potential applicability for treatment of oral disease.


Assuntos
Gases em Plasma , Pressão Atmosférica , Peróxido de Hidrogênio , Oxigênio Singlete , Streptococcus mutans
8.
Mater Sci Eng C Mater Biol Appl ; 105: 110049, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546363

RESUMO

The aim of this study was to evaluate whether combining two treatments to avoid biological aging of the surface of titanium and zirconia implants; i.e., storage in an aqueous solution after ultraviolet light (UV) or non-thermal atmospheric pressure plasma (NTP) treatment, yielded surface bioactivity comparable to that following post-15-min UV or NTP treatment storage under air or immediately after UV or NTP treatment. Grade IV titanium discs modified by large grit sand-blasting and acid-etching (SLA) and smooth zirconia discs were irradiated with UV or NTP and their surface properties were evaluated immediately and after storage for 8 weeks in distilled H2O (dH2O) and a sealed container under air. Approximately 15-30 nm-sized nano-protrusions were formed only on SLA surfaces in dH2O immediately after UV or NTP treatment. Immediate dH2O storage after UV or NTP treatment prevented hydrocarbon contamination and maintained elevated amounts of Ti and Zr. After 8 weeks, unlike zirconia, protein adsorption, cellular adhesion, and cytoskeletal development of MC3T3-E1 cells on SLA surfaces stored in dH2O immediately after UV treatment were further exceeding those immediately after UV or NTP treatments. UV treatment of SLA implants followed by wet storage can not only maintain but also strengthen bioactivity during shelf storage.


Assuntos
Implantes Experimentais , Teste de Materiais , Gases em Plasma/química , Titânio , Raios Ultravioleta , Zircônio , Animais , Pressão Atmosférica , Linhagem Celular , Camundongos , Propriedades de Superfície , Titânio/química , Titânio/farmacologia , Zircônio/química , Zircônio/farmacologia
9.
Anal Chim Acta ; 1082: 86-97, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31472716

RESUMO

Phospholipid fatty acids play the crucial role in biophysical properties and the function of cellular membranes. In the present study, an accurate and sensitive method was developed to quantify phospholipid fatty acids in biological samples by using chemical isotope labeling coupled with atmospheric pressure gas chromatography quadrupole-time-of-flight mass spectrometry (APGC/Q-TOF MS). APGC, a soft ionization source, was operated under proton-transfer condition by introducing methanol into the ionization source as a modifier, which provided high quantifiable molecular ion peaks to substantially enhance the sensitivity. Fatty acid standards were methylated with methanol-d4 to yield FAMEs-d3 that were used as one-to-one internal standards to ensure accurate quantification. Thirty fatty acids in phospholipids were accurately quantified in wide linear range with limit of quantification ranging from 84.6 to 113.2 pg/mL. The newly developed method was successfully applied to quantify phospholipid fatty acids in brain and liver tissues from both fat-1 and WT mice. This method might be expanded to quantify free fatty acids or other conjugated fatty acids in biological samples or other matrices.


Assuntos
Ácidos Graxos/análise , Fosfolipídeos/análise , Animais , Pressão Atmosférica , Química Encefálica , Caderinas/genética , Cromatografia Gasosa-Espectrometria de Massas/métodos , Marcação por Isótopo , Fígado/química , Camundongos Transgênicos , Estrutura Molecular , Fosfolipídeos/química
10.
J Chromatogr A ; 1606: 460384, 2019 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-31371199

RESUMO

With detection limits in the low ppbv-range, electron capture detectors (ECD) are the most sensitive GC-detectors available for electron affine compounds, such as pesticides or chlorofluorocarbons. The working principle is based on the generation of free electrons at atmospheric pressure, which are usually emitted from a radioactive Ni-63 source. However, the use of radioactive materials leads to regulatory restrictions regarding purchase, operation and disposal. Recently, we introduced a novel ECD based on a non-radioactive electron source, achieving comparable detection limits, e.g. 1 ppbv (6 ng/l) for 1,1,2-trichloroethane. However, the linear range was still below that of radioactive ECDs. In addition, the detector volume was too large to be used as a GC detector. We now present an improved version of this non-radioactive ECD with significantly increased linear range of 6.5∙103 for 1,1,2-trichloroethane by implementing pulsed operation using a newly developed, autonomous control electronics. In addition, the detector volume is reduced to 100 µl, leading to faster response times, less memory effects and thus less peak broadening. The improved ECD with non-radioactive electron source reaches similar analytical performance compared to commercially available radioactive ECDs and thus can be used as a possible replacement of radioactive ECDs.


Assuntos
Cromatografia Gasosa/instrumentação , Cromatografia Gasosa/métodos , Elétrons , Radioatividade , Pressão Atmosférica , Limite de Detecção , Praguicidas/análise
11.
Food Chem ; 301: 125240, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31387040

RESUMO

Cold plasma is an emerging technology increasingly applied in the agri-food industry. For fruit and vegetables, enzymatic browning is a common phenomenon, causing quality deterioration. The objective of this study was to illustrate the effect of microscale atmospheric-pressure plasma jet (µAPPJ) plasma on the horseradish peroxidase (HRP). Results showed that after plasma treatment for 10 min, the residual activity of HRP was decreased to around 17%, and modification of secondary and tertiary structures were confirmed. The atomic force microscope (AFM) analysis revealed that the aggregation of enzyme protein was enhanced with prolonging treatment time. It was concluded that the activity of HRP could be reduced with destruction of structures and deformation of microstructure induced by µAPPJ plasma. The current study attempted to provide new idea for inhibiting browning enzymes of fruit and vegetables with plasma technology through deeper understanding of the interaction mechanism of plasma active species with enzymes.


Assuntos
Temperatura Baixa , Peroxidase do Rábano Silvestre/química , Peroxidase do Rábano Silvestre/metabolismo , Gases em Plasma/farmacologia , Pressão Atmosférica
12.
ACS Appl Mater Interfaces ; 11(34): 31356-31366, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31381296

RESUMO

Plasma polymerization is gaining popularity as a technique for coating surfaces due to the low cost, ease of operation, and substrate-independent nature. Recently, the plasma polymerization (or deposition) of 2-oxazoline monomers was reported resulting in coatings that have potential applications in regenerative medicine. Despite the structural versatility of 2-oxazolines, only a few monomers have been subjected to plasma polymerization. Within this study, however, we explore the near atmospheric pressure plasma polymerization of a range of 2-oxazoline monomers, focusing on the influence of the aliphatic side-chain length (methyl to butyl) on the plasma polymerization process conditions as well as the properties of the obtained coatings. While side-chain length had only a minor influence on the chemical composition, clear effects on the plasma polymerization conditions were observed, thus gaining valuable insights in the plasma polymerization process as a function of monomer structure. Additionally, cytocompatibility and cell attachment on the coatings obtained by 2-oxazoline plasma polymerization was assessed. The coatings displayed strong cell interactive properties, whereby cytocompatibility increased with increasing aliphatic side-chain length of the monomer, reaching up to 93% cell viability after 1 day of cell culture compared to tissue culture plates. As this is in stark contrast to the antifouling behavior of the parent polymers, we compared the properties and composition of the plasma-polymerized coatings to the parent polymers revealing that a significantly different coating structure was obtained by plasma polymerization.


Assuntos
Pressão Atmosférica , Materiais Revestidos Biocompatíveis , Fibroblastos/metabolismo , Teste de Materiais , Gases em Plasma , Polimerização , Sobrevivência Celular , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologia , Fibroblastos/citologia , Humanos , Oxazóis/química , Oxazóis/farmacologia
13.
World Neurosurg ; 132: e687-e695, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31442657

RESUMO

OBJECTIVE: The climatic characteristics of aneurysmal subarachnoid hemorrhage (aSAH) have been reported, but consensus has not yet been reached. It is of great significance to elucidate the relationships between meteorological variation and aSAH in regions with specific climate patterns. We analyzed the occurrence of aSAH in the capital city of Fujian Province, China, through a multicenter, 5-year study, and aimed to reveal the meteorological influences on aSAH in the coastal city of eastern Fujian under the subtropical marine monsoon condition. METHODS: A total of 2555 consecutive patients with aSAH in Fuzhou were collected using specialized stroke admission database from January 2013 to December 2017. Meteorological parameters including temperature, atmospheric pressure, and humidity were obtained from China Surface Meteorological Station during the same period. Poisson regression was used to explore the association between meteorological parameters and aSAH to calculate the incidence rate ratios (IRRs) with corresponding 95% confidence intervals (CIs). Generalized additive model analysis further revealed the nonlinear relationships between weather and aSAH. RESULTS: Daily minimum temperature (IRR 0.976, 95% CI 0.958-0.996) and maximum pressure (IRR 1.022, 95% CI 1.001-1.042) were independently correlated with the onset of aSAH. Low temperature (below 16°C) and excessive atmospheric pressure (above 1008 hPa) increased the risk of aSAH. In addition, March in spring and December in winter were the 2 ictus peaks in Fuzhou throughout the year. CONCLUSIONS: Cold and excessive atmospheric pressure are triggers for the occurrence of aSAH; March in spring and December in winter are the predominant onset periods in Fuzhou.


Assuntos
Hemorragia Subaracnóidea/epidemiologia , Tempo (Meteorologia) , Adulto , Idoso , Pressão Atmosférica , China/epidemiologia , Clima , Temperatura Baixa , Feminino , Humanos , Umidade , Incidência , Masculino , Pessoa de Meia-Idade , Estações do Ano , Acidente Vascular Cerebral/epidemiologia , Temperatura Ambiente
14.
Ticks Tick Borne Dis ; 10(6): 101273, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31445876

RESUMO

Belgrade, the capital of the Republic of Serbia, is an endemic location for canine babesiosis caused by Babesia canis. This tick-borne disease occurs seasonally in regions with moderate continental climate. However, recent clinical data show that: 1) some cases of canine babesiosis have been recorded during the winter, and 2) canine babesiosis is spreading to the northern parts of Europe with a colder climate, which is a region previously free of this disease. Our study investigates the occurrence of canine babesiosis in different seasons over 2013-2016, and explores a short-term link between meteorological parameters and number of diagnosed cases of canine babesiosis in Belgrade. It also looks into possible long-term correlations that span one year before the onset of the disease. Based on 872 recorded cases over four years, our results show a bimodal seasonal distribution of canine babesiosis, with a pronounced peak in the spring, and a less conspicuous one in the autumn. Throughout the year, even over the coldest and warmest periods, there is a broad range of temperatures and relative humidities when the disease is recorded. Over one year prior to the spring and autumn onset of the disease, we found a noticeable impact of temperature and relative humidity, and to a lesser extent, of atmospheric pressure and cloud cover, on the number of diagnosed cases. These findings imply short-term and long-term relationships between occurrence of acute canine babesiosis and certain meteorological parameters, and they open further questions that need to be investigated in order to understand the epidemiology of this disease.


Assuntos
Pressão Atmosférica , Babesiose/epidemiologia , Doenças do Cão/epidemiologia , Tempo (Meteorologia) , Animais , Babesiose/parasitologia , Doenças do Cão/parasitologia , Cães , Umidade , Incidência , Estações do Ano , Sérvia/epidemiologia , Luz Solar , Temperatura Ambiente
15.
Food Microbiol ; 84: 103244, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31421772

RESUMO

Today, there is no effective non-thermal method to inactivate unwanted bacterial spores in foods. High-Pressure (HP) process has been shown to act synergistically with moderate heating and the bacteriocin nisin to inactivate spores but the mechanisms have not been elucidated. The purpose of the present work was to investigate in depth the synergy of HP and nisin on various foodborne spore species and to bring new elements of understandings. For this purpose, spores of Bacillus pumilus, B. sporothermodurans, B. licheniformis, B. weihenstephanensis, and Clostridium sp. were suspended in MES buffer, in skim milk or in a liquid medium simulating cooked ham brine and treated by HP at 500 MPa for 10 min at 50 °C or 20 °C. Nisin (20 or 50 IU/mL) was added at three different points during treatment: during HP, during and or in the plating medium of enumeration. In the latter two cases, a high synergy was observed with the inhibition of the spores of Bacillus spp. The evaluation of the germinated fraction of Bacillus spp. spores after HP revealed that this synergy was likely due to the action of nisin on HP-sensitized spores, rather than on HP-germinated spores. Thus, the combination of nisin and HP can lead to Bacillus spp. spore inhibition at 20 °C. And Nisin can act on HP-treated spores, even if they are not germinated. This paper provides new information about the inhibition of spores by the combination of HP and nisin. The high synergy observed at low temperature has not been reported yet and could allow food preservation without the use of any thermal process.


Assuntos
Pressão Atmosférica , Viabilidade Microbiana/efeitos dos fármacos , Nisina/farmacologia , Esporos Bacterianos/efeitos dos fármacos , Bacillus/efeitos dos fármacos , Bacillus/crescimento & desenvolvimento , Clostridium/efeitos dos fármacos , Clostridium/crescimento & desenvolvimento , Conservação de Alimentos , Temperatura Alta
16.
Artigo em Inglês | MEDLINE | ID: mdl-31336865

RESUMO

Dengue fever is one of the most common vector-borne diseases in the world and is mainly affected by the interaction of meteorological, human and land-use factors. This study aims to identify the impact of meteorological, human and land-use factors on dengue fever cases, involving the interplay between multiple factors. The analyses identified the statistically significant determinants affecting the transmission of dengue fever, employing cross-correlation analysis and the geo-detector model. This study was conducted in Guangzhou, China, using the data of confirmed cases of dengue fever, daily meteorological records, population density distribution and land-use distribution. The findings highlighted that the dengue fever hotspots were mainly distributed in the old city center of Guangzhou and were significantly shaped by meteorological, land-use and human factors. Meteorological factors including minimum temperature, maximum temperature, atmospheric pressure and relative humidity were correlated with the transmission of dengue fever. Minimum temperature, maximum temperature and relative humidity presented a statistically significant positive correlation with dengue fever cases, while atmospheric pressure presented statistically significant negative correlation. Minimum temperature, maximum temperature, atmospheric pressure and humidity have lag effects on the transmission of dengue fever. The population, community age, subway network density, road network density and ponds presented a statistically significant positive correlation with the number of dengue fever cases, and the interaction among land-use and human factors could enhance dengue fever transmission. The ponds were the most important interaction factors, which might strengthen the influence of other factors on dengue fever transmission. Our findings have implications for pre-emptive dengue fever control.


Assuntos
Dengue/epidemiologia , Dengue/transmissão , Conceitos Meteorológicos , Pressão Atmosférica , China/epidemiologia , Humanos , Umidade , Incidência , Densidade Demográfica , Temperatura Ambiente
17.
Biointerphases ; 14(4): 041001, 2019 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-31349747

RESUMO

When a tissue slice pretreated with gold nanoparticles is irradiated with a focused 532-nm continuous wave laser, desorption is observed to be uniform and stable, and its shape is sharp and steep. However, since the desorbed molecules are still electrically neutral particles in atmospheric pressure (AP), additional procedure of ionizing them is necessary for AP mass spectrometry (AP-MS) analysis. Therefore, the authors have combined an electrospray device with a simple chamber connected to the airflow-assisted particle transport equipment mounted at the mass spectrometer inlet. Subsequent ionization processes using an electrospray device enable the detection of several types of diacylglycerol molecules above 500 Da, which cannot be detected with the use of AP plasma jets. The authors also developed a remote AP-MS using a long and flexible sampling probe and a fiber laser with a slight modification of the proposed AP desorption and ionization method.


Assuntos
Pressão Atmosférica , Diglicerídeos/análise , Espectrometria de Massas por Ionização por Electrospray/métodos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos
18.
PLoS One ; 14(6): e0216817, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31233528

RESUMO

Biofilms are microbial communities encased in a protective matrix composed of exopolymeric substances including exopolysaccharides, proteins, lipids, and extracellular DNA. Biofilms cause undesirable effects such as biofouling, equipment damage, prostheses colonization, and disease. Biofilms are also more resilient than free-living cells to regular decontamination methods and therefore, alternative methods are needed to eradicate them. The use of non-thermal atmospheric pressure plasmas is a good alternative as plasmas contain reactive species, free radicals, and UV photons well-known for their decontamination potential against free microorganisms. Pseudomonas aeruginosa biofilms colonize catheters, indwelling devices, and prostheses. Plasma effects on cell viability have been previously documented for P. aeruginosa biofilms. Nonetheless, the effect of plasma on the biofilm matrix has received less attention and there is little evidence regarding the changes the matrix undergoes. The aim of this work was to study the effect plasma exerts mostly on the P. aeruginosa biofilm matrix and to expand the existing knowledge about its effect on sessile cells in order to achieve a better understanding of the mechanism/s underlying plasma-mediated biofilm inactivation. We report a reduction in the amount of the biofilm matrix, the loss of its tridimensional structure, and morphological changes in sessile cells at long exposure times. We show chemical and structural changes on the biofilm matrix (mostly on carbohydrates and eDNA) and cells (mostly on proteins and lipids) that are more profound with longer plasma exposure times. We also demonstrate the presence of lipid oxidation products confirming cell membrane lipid peroxidation as plasma exposure time increases. To our knowledge this is the first report providing detailed evidence of the variety of chemical and structural changes that occur mostly on the biofilm matrix and sessile cells as a consequence of the plasma treatment. Based on our results, we propose a comprehensive model explaining plasma-mediated biofilm inactivation.


Assuntos
Biofilmes/efeitos dos fármacos , Modelos Biológicos , Gases em Plasma/farmacologia , Pseudomonas aeruginosa/citologia , Pseudomonas aeruginosa/fisiologia , Pressão Atmosférica , Biofilmes/crescimento & desenvolvimento , Pseudomonas aeruginosa/efeitos dos fármacos , Fatores de Tempo
19.
Artigo em Inglês | MEDLINE | ID: mdl-31212876

RESUMO

The utility of agglomerative clustering methods for understanding dynamic systems that do not have a well-defined periodic structure has not yet been explored. We propose using this approach to examine the association between disease and weather parameters, to compliment the traditional harmonic regression models, and to determine specific meteorological conditions favoring high disease incidence. We utilized daily records on reported salmonellosis and non-specific enteritis, and four meteorological parameters (ambient temperature, dew point, humidity, and barometric pressure) in Barnaul, Russia in 2004-2011, maintained by the CliWaDIn database. The data structure was examined using the t-distributed stochastic neighbor embedding (t-SNE) method. The optimal number of clusters was selected based on Ward distance using the silhouette metric. The selected clusters were assessed with respect to their density and homogeneity. We detected that a well-defined cluster with high counts of salmonellosis occurred during warm summer days and unseasonably warm days in spring. We also detected a cluster with high counts of non-specific enteritis that occurred during unusually "very warm" winter days. The main advantage offered by the proposed technique is its ability to create a composite of meteorological conditions-a rule of thumb-to detect days favoring infectious outbreaks for a given location. These findings have major implications for understanding potential health impacts of climate change.


Assuntos
Pressão Atmosférica , Análise por Conglomerados , Clima Frio , Surtos de Doenças/estatística & dados numéricos , Microbioma Gastrointestinal , Umidade , Estações do Ano , Gastroenteropatias/epidemiologia , Humanos , Federação Russa/epidemiologia
20.
Molecules ; 24(13)2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31248028

RESUMO

Molecularly imprinted polymer (MIP) and magnetic molecularly imprinted polymer (mag-MIP) for solid extraction and pre-concentration of quercetin have been successfully prepared by thermal polymerization method using quercetin (Q) as a template, acrylamide (AA) as a functional monomer, and ethylene glycol dimethacrylate (EGDMA) as a cross-linking agent. The MIP and mag-MIP were successfully applied in analysis of quercetin by mass spectrometry (MS) methods. To perform ambient plasma ionization experiments, a setup consisting of the heated crucible, a flowing atmospheric-pressure afterglow (FAPA) plasma ion source, and amaZon SL ion trap (Bruker, Bremen, Germany) was used. The heated crucible with programmable temperature allowed desorption of the analytes from MIPs structure which resulted in their direct introduction into the ion stream. The results of Q-MIP/Q-mag-MIP and FAPA-MS measurements were compared with those of the analysis of quercetin by the ESI-MS method without extractions and pre-concentration of analytes on polymers. Limits of detection (LOD) for quercetin solutions in both positive and negative ESI-MS were established at 10-8 M and 10-7 M, respectively. The linearity (R2 = 0.9999) of the proposed analytical procedure for quercetin determination in positive ions was provided in the range between 10-4 M and 10-7 M. Moreover, the same parameters were established for FAPA-MS in positive ions, reaching LOD at 0.005 mg/gMIP and the linearity of the method in the range of 0.015-0.075 mg/gMIP with the correlation coefficient value R2 = 0.9850.


Assuntos
Pressão Atmosférica , Impressão Molecular , Polímeros/química , Quercetina/química , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas por Ionização por Electrospray/métodos , Análise Espectral , Termogravimetria
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