- Rua Giuseppe Máximo Scolfaro, 10000 - Polo II de Alta Tecnologia, Campinas - SP, 13083-970, Brasil
- Universidade de São Paulo, IQ - Instituto de Química, Post-DocUniversity of Sao Paulo, Chemistry, Graduate Studentadd
- Dr. Latif ullah Khan is a research fellow (postdoc) at Brazilian Nanotechnology National Laboratory - LNNano), Centro... moreDr. Latif ullah Khan is a research fellow (postdoc) at Brazilian Nanotechnology National Laboratory - LNNano), Centro Nacional de Pesquisa em Energia e Materiais - CNPEM, Campinas-SP, Brazil. I worked as a Post-doc researcher from May 2015 to December 2016 in Laboratory of f-Block Elements (Leb-f), Institute of Chemistry, University of São Paulo, Brazil. I hold Ph.D. in Chemistry (2015) with specialization in Inorganic Chemistry/Optical and Magnetic Nanomaterials/Photoluminescnce and Electronic Spectroscopy of rare earth ions/Nanomagnetism and Magnetic properties of bifunctional nanomaterials form Institute of Chemistry, University of São Paulo, Brazil. I obtained BSc (2003) with remarkable grade A1 from Gomel university, D.I. Khan, MSc (2006) in chemistry with specialization in organic chemistry from Institute of Chemical Sciences, University of Peshawar, KPK, Pakistan, where, I got good initiative in scientific research, my MSc dissertation research was focused on “Phytochemical and microbiological studies on Galium species (Rubiaceae)”. I joined H.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences (ICCBS), University of Karachi, Pakistan as junior research fellow (2007-2010) and got good experience in organic synthesis. Where, I worked on the project entitled as: Design and synthesis of glucagons like peptide-1 against and DPP-4 inhibitors for the treatment or prevention of diabetes”. I passed Graduate Rrecord Examination (GRE) in chemistry (2008) from ETS, United states of america (USA) with excellent grade.edit
- Professor Hermi F Britoedit
Research Interests:
To develop fluorescent bionanoprobe for cellular imaging, it is crucial to get precise insight on the particle–cell interaction, optical properties of QDs in and out of the cell, their movement in and out of the cell, and the final fate... more
To develop fluorescent bionanoprobe for cellular imaging, it is crucial to get precise insight on the particle–cell interaction, optical properties of QDs in and out of the cell, their movement in and out of the cell, and the final fate of particle.
Research Interests:
In this work, we evaluated the effect of protein corona formation on graphene oxide (GO) mixture toxicity testing (i.e., co-exposure) using the Daphnia magna model and assessing acute toxicity determined as immobilisation. Cadmium (Cd2+)... more
In this work, we evaluated the effect of protein corona formation on graphene oxide (GO) mixture toxicity testing (i.e., co-exposure) using the Daphnia magna model and assessing acute toxicity determined as immobilisation. Cadmium (Cd2+) and bovine serum albumin (BSA) were selected as co-pollutant and protein model system, respectively. Albumin corona formation on GO dramatically increased its colloidal stability (ca. 60%) and Cd2+ adsorption capacity (ca. 4.5 times) in reconstituted water (Daphnia medium). The acute toxicity values (48 h-EC50) observed were 0.18 mg L−1 for Cd2+-only and 0.29 and 0.61 mg L−1 following co-exposure of Cd2+ with GO and BSA@GO materials, respectively, at a fixed non-toxic concentration of 1.0 mg L−1. After coronation of GO with BSA, a reduction in cadmium toxicity of 110 % and 238% was achieved when compared to bare GO and Cd2+-only, respectively. Integration of datasets associated with graphene-based materials, heavy metals and mixture toxicity is esse...
Research Interests:
The increasing production and use of nanomaterials is causing serious concerns about their safety to human and environmental health. However, the applications of titanium dioxide nanoparticles (TiONP) and multiwalled carbon nanotubes... more
The increasing production and use of nanomaterials is causing serious concerns about their safety to human and environmental health. However, the applications of titanium dioxide nanoparticles (TiONP) and multiwalled carbon nanotubes (MWCNT) hybrids has grown considerably, due to their enhanced photocatalytic efficiency. To our knowledge, there are no reports available to the scientific community about their toxicity. In this work, we perform a toxicity assessment of TiONP and TiO-MWCNT nanohybrid materials using Zebrafish embryos standardized 96 h early life stage assay, under different exposure conditions (with and without UV light exposure). After exposure the parameters assessed were acute toxicity, hatching rate, growth, yolk sac size, and sarcomere length. In addition, μ-probe X-ray fluorescence spectroscopy (µ-XRF) was employed to observe if nanoparticles were uptaken by zebrafish embryos and consequently accumulated in their organisms. Neither TiONP nor TiO-MWCNT nanohybrids...
Research Interests:
Alzheimer's disease (AD) is a progressive brain disorder which occurs due to lower levels of acetylcholine (ACh) neurotransmitters, and results in a gradual decline in memory and other cognitive processes. Acetycholinesterase (AChE)... more
Alzheimer's disease (AD) is a progressive brain disorder which occurs due to lower levels of acetylcholine (ACh) neurotransmitters, and results in a gradual decline in memory and other cognitive processes. Acetycholinesterase (AChE) and butyrylcholinesterase (BChE) are considered to be primary regulators of the ACh levels in the brain. Evidence shows that AChE activity decreases in AD, while activity of BChE does not change or even elevate in advanced AD, which suggests a key involvement of BChE in ACh hydrolysis during AD symptoms. Therefore, inhibiting the activity of BChE may be an effective way to control AD associated disorders. In this regard, a series of quinoxaline derivatives 1-17 was synthesized and biologically evaluated against cholinesterases (AChE and BChE) and as well as against α- chymotrypsin and urease. The compounds 1-17 were found to be selective inhibitors for BChE, as no activity was found against other enzymes. Among the series, compounds 6 (IC50 = 7.7 ± 1...
Research Interests:
Aseries of new derivatives 1-11 of cinnamic acid have been synthesized by a facile procedure for esterification based on using of DCC as a coupling agent, DMAP and solvent system methylene chloride. The structures of all the newly... more
Aseries of new derivatives 1-11 of cinnamic acid have been synthesized by a facile procedure for esterification based on using of DCC as a coupling agent, DMAP and solvent system methylene chloride. The structures of all the newly synthesized derivatives 1-11 of cinnamic acid were assigned as 3-methyl-2-butenyl (E)-3-(3,4,5-trihydroxyphenyl)-2-propenoate (1), (2E)-3,7-dimethyl-2,6-octadienyl (E)-3-(3,4,5-trihydroxyphenyl)-2-propenoate (2),
(2Z)-3,7-dimethyl-2,6-octadienyl (E)-3-(3,4,5-trihydroxyphenyl)-2-propenoate
(3), (2E,6E)-3,7,11-trimethyl-2,6,10-dodecatrienyl (E)-3-(3,4,5-
trihydroxyphenyl)-2-propenoate (4), (2E)-3,7-dimethyl-2,6-octadienyl (E)-3-
(4-hydroxy-3-methoxyphenyl)-2-propenoate (5), (2Z)-3,7-dimethyl-2,6-
octadienyl (E)-3-(4-hydroxy-3-methoxyphenyl)-2-propenoate (6), (2E,6E)-
3,7,11-trimethyl-2,6,10-dodecatrienyl (E)-3-(4-hydroxy-3-methoxyphenyl)-2-
propenoate (7), 3-methyl-2-butenyl (E)-3-(4-hydroxy-3,5-dimethoxyphenyl)-
2-propenoate (8), (2E)-3,7-dimethyl-2,6-octadienyl (E)-3-(4-hydroxy-3,5-
dimethoxyphenyl)-2-propenoate (9), (2Z)-3,7-dimethyl-2,6-octadienyl (E)-3-
(4-hydroxy-3,5-dimethoxyphenyl)-2-propenoate (10) and (2E,6E)-3,7,11-
trimethyl-2,6,10-dodecatrienyl (E)-3-(4-hydroxy-3,5-dimethoxyphenyl)-2-
propenoate (11) by extensive NMR studies
(2Z)-3,7-dimethyl-2,6-octadienyl (E)-3-(3,4,5-trihydroxyphenyl)-2-propenoate
(3), (2E,6E)-3,7,11-trimethyl-2,6,10-dodecatrienyl (E)-3-(3,4,5-
trihydroxyphenyl)-2-propenoate (4), (2E)-3,7-dimethyl-2,6-octadienyl (E)-3-
(4-hydroxy-3-methoxyphenyl)-2-propenoate (5), (2Z)-3,7-dimethyl-2,6-
octadienyl (E)-3-(4-hydroxy-3-methoxyphenyl)-2-propenoate (6), (2E,6E)-
3,7,11-trimethyl-2,6,10-dodecatrienyl (E)-3-(4-hydroxy-3-methoxyphenyl)-2-
propenoate (7), 3-methyl-2-butenyl (E)-3-(4-hydroxy-3,5-dimethoxyphenyl)-
2-propenoate (8), (2E)-3,7-dimethyl-2,6-octadienyl (E)-3-(4-hydroxy-3,5-
dimethoxyphenyl)-2-propenoate (9), (2Z)-3,7-dimethyl-2,6-octadienyl (E)-3-
(4-hydroxy-3,5-dimethoxyphenyl)-2-propenoate (10) and (2E,6E)-3,7,11-
trimethyl-2,6,10-dodecatrienyl (E)-3-(4-hydroxy-3,5-dimethoxyphenyl)-2-
propenoate (11) by extensive NMR studies
Research Interests:
The thermodynamic properties of the fabrication of NiTiO 3 material in different reaction times are reported. The design of this material is accessible through a new efficient sol–gel methods, utilizing Ni(Ac) 2 Á4H 2 O and Ti(O i Pr) 4... more
The thermodynamic properties of the fabrication of NiTiO 3 material in different reaction times are reported. The design of this material is accessible through a new efficient sol–gel methods, utilizing Ni(Ac) 2 Á4H 2 O and Ti(O i Pr) 4 as starting materials for the formation of NiTiO 3 final product through thermal decomposition. The ther-mogravimetric (TG) and differential scanning calorimetric (DSC) techniques were used to analyze the reaction of Ni(Ac) 2 Á4H 2 O and Ti(O i Pr) 4 , which produces precursor materials at 0.5, 1, 2, 24, 48 and 72 h of reaction times, as well as the thermal stability of these precursors and the final product. The DSC data show an exothermic phenomenon of releasing large amount of energy of-1393 J/g at T Peak 655 K due to the first event of decomposition started at T Onset 607 K and finished at T Endset 663 K for the precursor materials obtained at 0.5 h of reaction, showing the presence of starting materials in this precursor. A similar exothermic behavior was observed in the sample of 1 h of reaction time and was vanished in the materials obtained at 2–72 h of reaction, indicating the influence of the time on the completion of reaction and formation of NiTiO 3 crystalline phase as final product of thermal decomposition. In addition, using the information obtained from the TG/DSC, XRD and FTIR analyses, the optimum temperature for the thermal decomposition of the precursor materials to NiTiO 3 with fairly high crystallinity was also determined and discussed.
Research Interests:
The fabrication of bifunctional nanocomposites, co-assembling photonic (RE 3þ) and magnetic (Fe 3 O 4) features into single entity nanostructures is reported through a facile method, using Fe 3 O 4 as core nanoparticles, which were coated... more
The fabrication of bifunctional nanocomposites, co-assembling photonic (RE 3þ) and magnetic (Fe 3 O 4) features into single entity nanostructures is reported through a facile method, using Fe 3 O 4 as core nanoparticles, which were coated with SiO 2 shell and further grafted with Eu 3þ and Tb 3þ complexes. The sophisticated structural features and morphologies of the core-shell Fe 3 O 4 @SiO 2-(TTA-RE-L) nano-materials were studied by Small-angle X-ray Scattering. The core mean size hD SAXS i, shell thickness DR, cluster size x and fractal dimension D F were determined by fitting the experimental SAXS data, corroborating through Transmission Electron Microscopy images. The DC magnetic properties at temperatures of 2 and 300 K were explored in support to the structural conclusions from SAXS and TEM analyses. The magnetic contributions of the RE 3þ ions to the magnetizations of the Eu 3þ and Tb 3þ nanocomposites were discussed. The photoluminescence properties of the Eu 3þ and Tb 3þ nano-composites based on the emission spectral data and luminescence decay curves were studied. The experimental intensity parameters (U l), lifetimes (t), emission quantum efficiencies (h) as well as radiative (A rad) and non-radiative (A nrad) decay rates were calculated and discussed, in addition, the structural conclusions from the values of the 4f-4f intensity parameters in the case of the Eu 3þ ion. These novel Eu 3þ and Tb 3þ nanocomposites may act as red and green emitting layers for magnetic and light converting molecular devices.
Research Interests:
The yellow emitting dysprosium oxysulfide (Dy 2 O 2 S) and dysprosium oxysulfate (Dy 2 O 2 SO 4) compounds were prepared from the thermal decomposition of hydrated dysprosium sulphate. The materials were characterized by using... more
The yellow emitting dysprosium oxysulfide (Dy 2 O 2 S) and dysprosium oxysulfate (Dy 2 O 2 SO 4) compounds were prepared from the thermal decomposition of hydrated dysprosium sulphate. The materials were characterized by using thermogravimetry (TG/DTG), X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) and Raman spectroscopies. The thermal stability temperatures at around 1151 and 1313 K were determined for the Dy 2 O 2 S and Dy 2 O 2 SO 4 materials, respectively. The photolumines-cence properties of the dysprosium oxysulfide were investigated, showing narrow emission bands assigned to the 4 F 9/2 → 6 H J intracon-figurational transitions of the Dy 3+ ion. The yellow emission color of this phosphor suggests that the Dy 2 O 2 S is promising material for applications in LEDs.
Research Interests:
Alzheimer's disease (AD) is a progressive brain disorder which occurs due to lower levels of acetylcholine (ACh) neurotransmitters, and results in a gradual decline in memory and other cognitive processes. Acetycholinesterase (AChE) and... more
Alzheimer's disease (AD) is a progressive brain disorder which occurs due to lower levels of acetylcholine (ACh) neurotransmitters, and results in a gradual decline in memory and other cognitive processes. Acetycholinesterase (AChE) and butyrylcholinesterase (BChE) are considered to be primary regulators of the ACh levels in the brain. Evidence shows that AChE activity decreases in AD, while activity of BChE does not change or even elevate in advanced AD, which suggests a key involvement of BChE in ACh hydrolysis during AD symptoms. Therefore, inhibiting the activity of BChE may be an effective way to control AD associated disorders. In this regard, a series of quinoxaline derivatives 1-17 was synthesized and biologically evaluated against cholinesterases (AChE and BChE) and as well as against-chymotrypsin and urease. The compounds 1-17 were found to be selective inhibitors for BChE, as no activity was found against other enzymes. Among the series, compounds 6 (IC 50 = 7.7 ± 1.0 0M) and 7 (IC 50 = 9.7 ± 0.9 0M) were found to be the most active inhibitors against BChE. Their IC 50 values are comparable to the standard, galantamine (IC 50 = 6.6 ± 0.38 M). Their considerable BChE inhibitory activity makes them selective candidates for the development of BChE in-hibitors. Structure-activity relationship (SAR) of this new class of selective BChE inhibitors has been discussed.
Research Interests:
The design of bifunctional magnetic lumines-cent nanomaterials containing Fe 3 O 4 functionalized with rare earth ion complexes of calixarene and β-diketonate ligands is reported. Their preparation is accessible through a facile one-pot... more
The design of bifunctional magnetic lumines-cent nanomaterials containing Fe 3 O 4 functionalized with rare earth ion complexes of calixarene and β-diketonate ligands is reported. Their preparation is accessible through a facile one-pot method. These novel Fe 3 O 4 @calix-Eu(TTA) (TTA = thenoyltrifluoroacetonate) and Fe 3 O 4 @calix-Tb(ACAC) (ACAC = acetylacetonate) magnetic luminescent nanomateri-als show interesting superparamagnetic and photonic properties. The magnetic properties (M-H and ZFC/FC measurements) at temperatures of 5 and 300 K were explored to investigate the extent of coating and the crystallinity effect on the saturation magnetization values and blocking temperatures. Even though magnetite is a strong luminescence quencher, the coating of the Fe 3 O 4 nanoparticles with synthetically functionalized rare earth complexes has overcome this difficulty. The intramolecular energy transfer from the T 1 excited triplet states of TTA and ACAC ligands to the emitting levels of Eu 3+ and Tb 3+ in the nanomaterials and emission efficiencies are presented and discussed, as well as the structural conclusions from the values of the 4f−4f intensity parameters in the case of the Eu 3+ ion. These novel nanomaterials may act as the emitting layer for the red and green light for magnetic light-converting molecular devices (MLCMDs).