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ZnMn2O4 as a cathode material in an aqueous solution of ZnCl2 and Mn(NO3)2 for Zn-ion batteries
Get PDFDue to Li-ion batteries having become the main power source of most portable
electronic devices, their waste has also become a significant environmental problem.
To find batteries that would be environmentally friendly, this work examines Zn-ion
batteries in an aqueous solution of ZnCl2. The ZnMnO4 was synthesized by glycine
nitrate combustion of Zn(NO3)2, Mn(NO3)2 and glycine as a chelating agent [1]. The
structure of the material obtained was characterized by X-ray powder diffraction
(XRPD) showing a spinel structure; the morphology was characterized by scanning
electron microscopy (SEM) showing that nano-particles were obtained. The
electrochemical characterization was done by cyclic voltammetry in an aqueous
solution of ZnCl2. The mixture pasted on the glossy carbon electrode was prepared
by mixing the cathode material, graphite and polyvinyl diene difluoride (PVDF) in a
ratio 85:10:5 [2]. Due to the low discharge capacity obtained of ~14 mAh g-1 for 5
mV s-1, further examination was done by adding 1 ml of 1M Mn(NO3)2 into 10ml of
a saturated aqueous solution of ZnCl2. After adding the Mn(NO3)2 , the discharge
capacity increased from ~14 mAh g-1 to ~65 mAh g-1 at the same polarization rate,
making this additive a promising one for aqueous Zn-ion batteries. Further
investigation needs to be directed to adding the same additive in larger amounts
compared to 1ml to the same volume of the electrolyte. The results obtained suggest
the aqueous Zn-ion battery described in this work to be a potentially promising
“green” battery that may replace harmful commercial organic Li-ion batteries
Crystallographic Structure and Quantum-Chemical Analysis of Biologically Active Co(III)-Pyridoxal– Isothiosemicarbazone Complex
Get PDFSemicarbazones and their transition metal complexes have been investigated as biologically active compounds. This study explores the synthesis, X-ray crystallographic structure, and characterization of a novel Co(III) complex cation with a pyridoxal-isothiosemicarbazone (PLITSC) ligand, [Co(PLITSC-2H)(NH3)3 ]+. The structure of the complex was further elucidated by the elemental analysis and spectroscopic techniques (IR and UV–VIS). Hirshfeld surface analysis was applied for the investigation of intermolecular interactions governing crystal structure. Optimization was performed at the B3LYP/6-31+ G(d,p)(H,C,N,O,S)/LanL2DZ(Co) level of theory without any geometrical con straints. The selected level of theory’s applicability was proven after comparing experimental and theoretical bond lengths and angles. The antibacterial activity of the complex towards E. coli and B. subtilis was determined and qualified as moderate compared to Streptomycin. The formation of free radical species in the presence of the complex was further verified in the fluorescence microscopy measurements. The molecular docking towards neural nitric-oxide synthase in the brain has shown that the complex structure and relative distribution of ligands were responsible for the binding to amino acids in the active pocket
Differential Antioxidant Response to Supplemental UV-B Irradiation and Sunlight in Three Basil Varieties
Get PDFThree basil plant varieties (Ocimum basilicum var. Genovese, Ocimum x citriodorum, and Ocimum
basilicum var. purpurascens) were grown under moderate light (about 300 umol photons m-2 s-1)
in a glasshouse or growth chamber and then either transferred to an open field (average daily dose:
29.2 kJ m-2 d-1) or additionally exposed to UV-B irradiation in a growth chamber (29.16 kJ m-2 d-1),
to reveal the variety-specific and light-specific acclimation responses. Total antioxidant capacity
(TAC), phenolic profile, ascorbate content, and class III peroxidase (POD) activity were used to determine
the antioxidant status of leaves under all four light regimes. Exposure to high solar irradiation
at the open field resulted in an increase in TAC, total hydroxycinnamic acids (HCAs, especially
caffeic acid), flavonoids, and epidermal UV-absorbing substances in all three varieties, as well as a
two-fold increase in the leaf dry/fresh weight ratio. The supplemental UV-B irradiation induced
preferential accumulation of HCAs (rosmarinic acid) over flavonoids, increased TAC and POD activity,
but decreased the ascorbate content in the leaves, and inhibited the accumulation of epidermal
flavonoids in all basil varieties. Furthermore, characteristic leaf curling and UV-B-induced inhibition
of plant growth were observed in all basil varieties, while a pro-oxidant effect of UV-B was indicated
with H2O2 accumulation in the leaves and spotty leaf browning. The extent of these morphological
changes, and oxidative damage depended on the basil cultivar, implies a genotype-specific tolerance
mechanism to high doses of UV-B irradiation
Temperature stability of Streptomyces cyaneus lacasse heterologously expressed within S. cerevisiae cell walls immobilized within tyramine-modified alginate beads using visible light photopolymerization
No full textPhoto-crosslinked modified alginate hydrogels are useful in various biomedical
applications, including tissue engineering, wound healing, regenerative medicine,
controlled drug delivery, and 3D bioprinting1
. Traditional UV-crosslinkable hydrogels,
often used for injectable soft tissue regeneration, have faced hurdles in clinical translation
due to concerns about UV light's potential harm2
. The use of visible light and safer
photoinitiators during hydrogel synthesis significantly boosts their efficacy in
immobilizing biocatalysts and advancing tissue engineering applications3
. In this study the
synthesis of tyramine modified alginate were optimized and spectral characterization of the
modified alginate by ultraviolet-visible spectroscopy, infrared spectroscopy and proton
nuclear magnetic resonance. Laccase from Streptomyces cyaneus was expressed on the
surface of yeast cell walls, followed by cell lysis and immobilization of obtained cell walls
withinin calcium-tyramine-alginate beads. Additional cross-linking of the obtained
immobilizers by photopolymerization with visible light, in the presence of the riboflavin
photoinitiator, in order to obtain a biocatalyst with improved characteristics and the ability
to be used multiple times. The temperature stability of both photopolymerized and non photopolymerized biocatalysts was determined. At 60℃, the cell wall-immobilized laccase
entrapped in photopolymerized alginate-tyramine beads exhibited a 30% increase in
enzymatic activity compared to the non-photopolymerized tyramine-alginate biocatalyst
and 2.5 times higher activity compared to the enzyme immobilized in native alginate
beads
Towards an understanding of southern peri-Pannonian lacustrine depositional cycles: Interplay of sediment delivery and shifting intrabasinal height, a case study of drilled Neogene sediments from northwest Toplica Basin (Central Serbia) April 2024
No full textA multidisciplinary approach allowed the reconstruction of the shallow, highly complex Neogene
lacustrine-type sedimentological interplay between the peri-Pannonian (sub)basin subsidence and its seafloor topography. The current study further discusses the mechanism of localized uplift and subsidence by analyzing depositional cycles of middle Miocene sediments drilled in a northwestern or shallower Toplica Basin depocenter (borehole BL4, depth up to 630 m; Central Serbia). Supported by recent constraints on a deeper basinal section of eastern and western subbasin depocenters, the composite study of the segmented Toplica Basin involved geological, sedimentological, mineralogical, inorganic, and organic geochemical analysis, as well as constraints on interchanging geodynamic drivers. The data were extracted from thirty-one selected samples from four sedimentary lith omembers: A, B, C, and D. The architecture of these deposits reflects an intricate pattern influenced by complex lake bottom and subsurface geology (dis)connecting the two depocenters. The investigated Neogene deposition, as a whole, was dominantly controlled by a lithospheric-scale extensional graben system (involving the Jastrebac core complex-type tectonic exhumation) developed on top of the underlying Serbo-Macedonian basement unit. The crustal extension allowed rapid material inflow from other exposed sequences of the juvenile basin, including the abutting surface exposures. During the initial stretching and basin subsidence stage, sediment inflow towards the eastern Toplica depocenter was hindered. The influx of surface-eroded material was interrupted by a natural “obstacle”. In turn, such a configuration facilitated voluminous material transport into the western depocenter of the basin,
thereby controlling the deposition of lithomembers A and B. After the deposition of lithomember B
ceased, the “barrier”, or likely intrabasinal structural high, contributed to a reversal of the former
westward-directed transport. In that manner, the vertical movements of the structural high enabled
material transfer typical for the eastern basin segment, consequently prompting a sedimentary
development of the lithomembers C and D.
In this context, mineralogical and geochemical differences between the sequences are used as tracers of depositional changes affected by tectonic events. Sequences of sand and gravel layers of upper lithomembers C and D pointed out that alluvial processes strongly influenced their depositional cycle. On the other hand, a more pronounced presence of sulfide minerals (pyrite concretions) in lithomembers A and B correlated with a calm and anoxic paleoenvironment. The elevated trend of mixed terrigenous and/or microbiologically reworked organic matter (higher carbon/nitrogen (C/N) ratio and terrigenous/aquatic (TAR) ratio, the lower sum of steroids/sum of hopanoids (S/H)) ratio, deposited under anoxic-dysoxic freshwater lacustrine conditions (higher pristane/phytane (Pr/Ph) ratio, absence of squalane (iC30) and b-carotane), is observed towards a shallower section of the borehole (lithomembers C and D)
Hydrogen evolution at Ni foam electrodes and Ni-Sn coated Ni foam electrodes
No full textThe hydrogen evolution reaction (HER) was investigated in 1.0 M KOH at 25 °C at Ni foams with different pore sizes (450–1200 µm), and at the Ni-Sn/Ni foam electrodes, where Ni-Sn alloys were electrodeposited from the pyrophosphate-glycine bath using controlled potential coulometry (CPC) technique. The cross-section analysis revealed that rough Ni-Sn alloy covers complete available inner and outer foam surface, while investigated coating composition varied from 62 to 80 at% Ni (20–38 at% Sn). Comparing the HER polarization curves, the overpotential at j = −200 mA cm−2 was 427 mV lower for Ni-Sn samples than for bare Ni foams, while Tafel slopes changed from − 120 mV dec−1 at bare Ni foams to − 50 mV dec−1 for Ni-Sn/Ni foam samples. The lowest overpotential at − 100 mA cm−2 achieved is as low as − 77 mV. These cathodes could be promising 3D materials for industrial water electrolysis in zero-gap membrane flow cells
Using Front-Face Fluorescence Spectroscopy and Biochemical Analysis of Honey to Assess a Marker for the Level of Varroa destructor Infestation of Honey Bee (Apis mellifera) Colonies
Get PDFVarroa destructor is a parasitic mite responsible for the loss of honey bee (Apis mellifera)
colonies. This study aimed to find a promising marker in honey for the bee colony infestation level
using fluorescence spectroscopy and biochemical analyses. We examined whether the parameters of
the honey samples’ fluorescence spectra and biochemical parameters, both related to proteins and
phenolics, may be connected with the level of honey bee colonies’ infestation. The infestation level
was highly positively correlated with the catalase activity in honey (r = 0.936). Additionally, the
infestation level was positively correlated with the phenolic spectral component (r = 0.656), which
was tentatively related to the phenolics in honey. No correlation was found between the diastase
activity in honey and the colonies’ infestation level. The results indicate that the catalase activity in
honey and the PFC1 spectral component may be reliable markers for the V. destructor infestation level
of the colonies. The obtained data may be related to the honey yield obtained from the apiaries
Gajenje šuma u uslovima narušenog stanja i kompleksnih zahteva društva na području Nacionalnog parka ,,Fruška gora”
Get PDFPrimena na savremenim osnovama racionalizovanih mera gajenja šuma u cilju održanja i unapređenja šuma na području Nacionalnog parka „Fruška gora” predstavlja najznačajniji segment gazdovanja šumama, imajući u vidu njihovo antropogeno narušeno stanje i namenu. Za unapređenje stanja potrebne su intenzivne uzgojne mere u pojedinim fazama razvoja sastojina, što je suprotno njihovoj permanentnoj pasivnoj zaštiti. Osnovni razlozi za primenu ovih mera nalaze se u izdanačkom poreklu sastojina na preko 82% površine Nacionalnog parka i dominaciji lipe u odnosu na glavne edifikatore (hrastove i bukvu). Na osnovama ekosistemskog pristupa u gazdovanju šumama, a posebno u uslovima sve izraženijih klimatskih promena, mere gajenja šuma je potrebno racionalizovano usklađivati sa biološko-ekološkim zahtevima glavnih vrsta drveća i dominantnim prirodnim procesima u šumskim ekosistemima, odnosno potrebno je uvoditi elemente prirodi bliskog gazdovanja šumama. U radu se, na osnovu raspoloživih podataka i stavova u planskim dokumentima, kao i rezultata sopstvenih istraživanja, ukazuje na najznačajnija opredeljenja gajenja šuma u cilju ostvarivanja njihove posebne namene u Nacionalnom parku.The application of silviculture measures on contemporary, rationalized basis in order to sustain and improve forests in the area of the National park „Fruška Gora”, is the most important segment of forest management, having in mind their anthropogenically deteriorated conditions and their purpose. For the improvement of stand conditions, intensive silvicultural tending measures are necessary in certain phases of development of the stands which is contrary to the passive protection. The main reasons for the application of these measures are in the coppice origin of the stands on over 82% of the area of National park and the silver lime dominance compared to other edificators (oaks and beech). On the basis of the ecosystem approach in forest management, and especially in conditions of more pronounced climate change, the silvicultural measures need to be rationally synchronized with biological-ecological demands of the main species and dominant processes in forest ecosystems. In other words, there is a need to implement the elements of close-to-nature forest management. This paper points toward the most important determinations of silviculture in order to achieve the goals of special-purpose forests in the National park
Wastewater treatment by aminated peroxidase in alginate hydrogel
Get PDFPhenols are highly toxic organic compounds found in wastewater due to various industries’ pollution. Its removal is of great importance for human and animal health. Enzymatic wastewater treatment has several advantages over traditional methods. Enzyme immobilization onto solid carriers enables its reusability and lowers the cost of treatment. In this work, immobilized horseradish peroxidase on chemically modified alginate hydrogel was tested for phenol removal. The reusability of the tested immobilizate was monitored in repeated cycles. After five consecutive cycles, the remaining activity of the immobilized enzyme was 54%. The obtained result shows the potential for using this immobilizate for wastewater treatment
Can glial cells save neurons in epilepsy?
Get PDFEpilepsy is a neurological disorder caused by the pathological hyper-synchronization of neuronal discharges. The fundamental research of epilepsy mechanisms and the targets of drug design options for its treatment have focused on neurons. However, approximately 30% of patients suffering from epilepsy show resistance to standard anti-epileptic chemotherapeutic agents while the symptoms of the remaining 70% of patients can be alleviated but not completely removed by the current medications. Thus, new strategies for the treatment of epilepsy are in urgent demand. Over the past decades, with the increase in knowledge on the role of glia in the genesis and development of epilepsy, glial cells are receiving renewed attention. In a normal brain, glial cells maintain neuronal health and in partnership with neurons regulate virtually every aspect of brain function. In epilepsy, however, the supportive roles of glial cells are compromised, and their interaction with neurons is altered, which disrupts brain function. In this review, we will focus on the role of glia-related processes in epileptogenesis and their contribution to abnormal neuronal activity, with the major focus on the dysfunction of astroglial potassium channels, water channels, gap junctions, glutamate transporters, purinergic signaling, synaptogenesis, on the roles of microglial inflammatory cytokines, microglia-astrocyte interactions in epilepsy, and on the oligodendroglial potassium channels and myelin abnormalities in the epileptic brain. These recent findings suggest that glia should be considered as the promising next-generation targets for designing anti-epileptic drugs that may improve epilepsy and drug-resistant epilepsy.kategorija casopsisa M2