2,037 research outputs found
Synthesis, Characterization and Adsorption Properties of Protonated Cross-linked Chitosan for the Removal of Basic Blue 3 Dye from Wastewater
Dye wastewater remediation is important for water treatment and adsorption is an effective treatment process. A modified protonated crosslinked chitosan (PCCH) was synthesized and compared with pure chitosan for a cationic basic blue 3 dye removal from an aqueous solution. Adsorbent were characterized using techniques such as SEM/EDX, FTIR, and BET analysis. Batch experiments were conducted under optimized pH, adsorbentdosage and initial concentration at room temperature within a range of one hour. The highest adsorption efficiency was 91.93% and 58.97%, adsorption capacity 6.19 mg/g and 3.83 mg/g for PCCH and pure chitosan respectively. Result however fitted well with Langmuir isotherm and pseudo-second-order kinetics models(R2>0.99).
Keywords: Adsorbent, Adsorption, Basic Blue 3, Chitosan, Crosslinking, Wastewate
Proton Heating in Solar Wind Compressible Turbulence with Collisions between Counter-propagating Waves
Magnetohydronamic turbulence is believed to play a crucial role in heating
the laboratorial, space, and astrophysical plasmas. However, the precise
connection between the turbulent fluctuations and the particle kinetics has not
yet been established. Here we present clear evidence of plasma turbulence
heating based on diagnosed wave features and proton velocity distributions from
solar wind measurements by the Wind spacecraft. For the first time, we can
report the simultaneous observation of counter-propagating magnetohydrodynamic
waves in the solar wind turbulence. Different from the traditional paradigm
with counter-propagating Alfv\'en waves, anti-sunward Alfv\'en waves (AWs) are
encountered by sunward slow magnetosonic waves (SMWs) in this new type of solar
wind compressible turbulence. The counter-propagating AWs and SWs correspond
respectively to the dominant and sub-dominant populations of the imbalanced
Els\"asser variables. Nonlinear interactions between the AWs and SMWs are
inferred from the non-orthogonality between the possible oscillation direction
of one wave and the possible propagation direction of the other. The associated
protons are revealed to exhibit bi-directional asymmetric beams in their
velocity distributions: sunward beams appearing in short and narrow patterns
and anti-sunward broad extended tails. It is suggested that multiple types of
wave-particle interactions, i.e., cyclotron and Landau resonances with AWs and
SMWs at kinetic scales, are taking place to jointly heat the protons
perpendicularly and parallel
Endemic mycosis
This article is made available for unrestricted research re-use and secondary analysis in any form or by any means with acknowledgement of the original source. These permissions are granted for the duration of the World Health Organization (WHO) declaration of COVID-19 as a global pandemi
Synthesis, Characterization and Optimization of Magnetite Molecularly Imprinted Polymer for Application in the Removal of Non-Steroidal Anti Inflammatory Drugs (NSAIDS)
Diclofenac (DCF) remains one of the most extensively used sold anti-inflammatory and analgesics that have been in use for an extended period. It has been widely detected in aquatic environments at concentrations that are indicative of detrimental environmental effects in addition to its inclusion on the EU's first watch list therefore, its removal from the environment is crucial. In this study, a selective Molecularly Imprinted Polymer(MIP) was synthesized via a bulk polymerization strategy with methacrylic acid (MAA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, Azobisisobutyronitrile (AIBN) as initiator and Diclofenac sodium (DCF) as the template molecule. The structure of the prepared MIP/ NIP was characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM) and Transmission Electron Microscopy (TEM). Several parameters influencing the adsorption efficiency of the MIP were optimized via the batch adsorption experiment. The results revealed that the maximum removal efficiency of the MIP (79%) was achieved at the optimized conditions of pH 2, 10 mL of 10 mg/L of adsorbate solution at 60 min contact time which was higher than its corresponding non molecularly imprinted polymer (NIP) whichwas (57%). The result of the reusability study showed that the adsorbent can be reused up to five cycles, hence it is efficient and promising for the removal of diclofenac from aqueous media.
Keywords: NSAIDs, optimization, removal, reusability, selectivit
Precision Electron Measurements in the Solar Wind at 1 au from NASA's Wind Spacecraft
This work aims to characterize precisely and systematically the non-thermal
characteristics of the electron Velocity Distribution Function (eVDF) in the
solar wind at 1 au using data from the Wind spacecraft. We present a
comprehensive statistical analysis of solar wind electrons at 1 au using the
electron analyzers of the 3D-Plasma instrument on board Wind. This work uses a
sophisticated algorithm developed to analyze and characterize separately the
three populations - core, halo and strahl - of the eVDF up to 2 keV. The eVDF
data are calibrated using independent electron parameters obtained from the
quasi-thermal noise around the electron plasma frequency measured by the
Thermal Noise Receiver. The code determines the respective set of total
electron, core, halo and strahl parameters through non-linear least-square fits
to the measured eVDF, taking properly into account spacecraft charging and
other instrumental effects. We use four years, ~ 280000 independent
measurements of core, halo and strahl parameters to investigate the statistical
properties of these different populations in the solar wind. We discuss the
distributions of their respective densities, drift velocities, temperature, and
temperature anisotropies as functions of solar wind speed. We also show
distributions with solar wind speed of the total density, temperature,
temperature anisotropy and heat flux, as well as those of the proton
temperature, proton-to-electron temperature ratio, proton and electron beta.
Intercorrelations between some of these parameters are also discussed. The
present dataset represents the largest, high-precision, collection of electron
measurements in the pristine solar wind at 1~AU. It provides a new wealth of
information on electron microphysics. Its large volume will enable future
statistical studies of parameter combinations and their dependencies under
different plasma conditions.Comment: total of 21 pages, 17 figures, 1 appendix and 7 table
Relation entre la sensibilisation locomotrice à la nicotine et les variations pondérales chez les rates gestantes et de leur descendance suite à un traitement chronique à la nicotine
Le tabagisme est la consommation quotidienne de la nicotine qui constitue un sérieux problème de santé publique. Parmi ces effets qui favorisent le maintien du tabagisme et même son établissement, celui sur le poids est important. Les nombreuses études publiées jusqu’à présent, permettent d'une part d’élucider les différents effets de cette drogue et d'autre part ont révélé les mécanismes impliqués. Dans ce travail, nous présenterons les résultats obtenus à la suite d’un traitement chronique à la nicotine (0,4mg/kg) des rates gestantes et de leur descendance. Cette étude a été menée en parallèle à une étude de sensibilisation locomotrice à la nicotine. Elle consiste à prélever quotidiennement le poids des rats avant même d’enregistrer leur activité locomotrice dans des couloirs circulaires (cyclotrons) en fonction du temps et pour une période de 2 mois. Les résultats obtenus sont très significatifs. Dès les premières injections on constate, chez les rates nicotinées, une augmentation pondérale plus faible par rapport aux témoins. A long terme, cette différence de poids se maintient et le sous poids alors constaté s’installe définitivement même après l’arrêt du traitement. Fait curieux dans la mesure où seule la nicotine semblerait responsable de cet effet, d’autant plus que les mêmes observations ont été faites sur la descendance.Mots-clés : tabagisme, nicotine, rates gestantes, descendance, poids, activité locomotrice.Smoking is the daily consumption of nicotine is a serious public health problem. Among these effects that promote continued smoking and even its establishment, that the weight is important. Numerous studies published so far, on the one hand allow to elucidate the different effects of this drug and also revealed the mechanisms involved. In this work, we present the results obtained after chronic treatment with nicotine (0.4 mg / kg) of pregnant rats and their progeny. This study was conducted in parallel with a study of locomotor sensitization to nicotine. It involves taking daily weights of the rats before they register their locomotor activity in circular corridors (cyclotrons) versus time for a period of 2 months. The results are highly significant. From the first there injections, rats nicotinic, increased weight lower compared to controls. In the long term, this difference in weight and maintaining weight then observed under settled permanently, even after cessation of treatment. Curious fact to the extent that only the nicotine seems responsible for this effect, especially since the same observations were made on the progeny.Keywords : smoking, nicotine, gestating rats, progeny, weight, locomotor activity
Surface step effects on Si (100) under uniaxial tensile stress, by atomistic calculations
This paper reports a study of the influence of the step at a silicon surface
under an uniaxial tensile stress, using an empirical potential. Our aim was to
find conditions leading to nucleation of dislocations from the step. We
obtained that no dislocations could be generated with such conditions. This
behaviour, different from the one predicted for metals, could be attributed
either to the covalent bonding or to the cubic diamond structure
Photoconductance Quantization in a Single-Photon Detector
We have made a single-photon detector that relies on photoconductive gain in
a narrow electron channel in an AlGaAs/GaAs 2-dimensional electron gas. Given
that the electron channel is 1-dimensional, the photo-induced conductance has
plateaus at multiples of the quantum conductance 2e/h. Super-imposed on
these broad conductance plateaus are many sharp, small, conductance steps
associated with single-photon absorption events that produce individual
photo-carriers. This type of photoconductive detector could measure a single
photon, while safely storing and protecting the spin degree of freedom of its
photo-carrier. This function is valuable for a quantum repeater that would
allow very long distance teleportation of quantum information.Comment: 4 pages, 4 figure
Characterizing and prognosticating chronic lymphocytic leukemia in the elderly: prospective evaluation on 455 patients treated in the United States.
BACKGROUND: Median age at diagnosis of patients with chronic lymphocytic leukemia (CLL) is \u3e 70 years. However, the majority of clinical trials do not reflect the demographics of CLL patients treated in the community. We examined treatment patterns, outcomes, and disease-related mortality in patients ≥ 75 years with CLL (E-CLL) in a real-world setting.
METHODS: The Connect® CLL registry is a multicenter, prospective observational cohort study, which enrolled 1494 adult patients between 2010-2014, at 199 US sites. Patients with CLL were enrolled within 2 months of initiating first line of therapy (LOT1) or a subsequent LOT (LOT ≥ 2). Kaplan-Meier methods were used to evaluate overall survival. CLL- and infection-related mortality were assessed using cumulative incidence functions (CIF) and cause-specific hazards. Logistic regression was used to develop a classification model.
RESULTS: A total of 455 E-CLL patients were enrolled; 259 were enrolled in LOT1 and 196 in LOT ≥ 2. E-CLL patients were more likely to receive rituximab monotherapy (19.3 vs. 8.6%; p \u3c 0.0001) and chemotherapy-alone regimens (p \u3c 0.0001) than younger patients. Overall and complete responses were lower in E-CLL patients than younger patients when given similar regimens. With a median follow-up of 3 years, CLL-related deaths were higher in E-CLL patients than younger patients in LOT1 (12.6 vs. 5.1% p = 0.0005) and LOT ≥ 2 (31.3 vs. 21.5%; p = 0.0277). Infection-related deaths were also higher in E-CLL patients than younger patients in LOT1 (7.4 vs. 2.7%; p = 0.0033) and in LOT ≥ 2 (16.2 vs. 11.2%; p = 0.0786). A prognostic score for E-CLL patients was developed: time from diagnosis to treatment \u3c 3 months, enrollment therapy other than bendamustine/rituximab, and anemia, identified patients at higher risk of inferior survival. Furthermore, higher-risk patients experienced an increased risk of CLL- or infection-related death (30.6 vs 10.3%; p = 0.0006).
CONCLUSION: CLL- and infection-related mortality are higher in CLL patients aged ≥ 75 years than younger patients, underscoring the urgent need for alternative treatment strategies for these understudied patients.
TRIAL REGISTRATION: The Connect CLL registry was registered at clinicaltrials.gov: NCT01081015 on March 4, 2010
Probing the potential landscape inside a two-dimensional electron-gas
We report direct observations of the scattering potentials in a
two-dimensional electron-gas using electron-beam diffaction-experiments. The
diffracting objects are local density-fluctuations caused by the spatial and
charge-state distribution of the donors in the GaAs-(Al,Ga)As heterostructures.
The scatterers can be manipulated externally by sample illumination, or by
cooling the sample down under depleted conditions.Comment: 4 pages, 4 figure
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