The ultrafast photoinduced ring-opening of 1,3-cyclohexadiene constitutes a textbook example of electrocyclic reactions in organic chemistry and a model for photobiological reactions in vitamin D ...synthesis. Although the relaxation from the photoexcited electronic state during the ring-opening has been investigated in numerous studies, the accompanying changes in atomic distance have not been resolved. Here we present a direct and unambiguous observation of the ring-opening reaction path on the femtosecond timescale and subångström length scale using megaelectronvolt ultrafast electron diffraction. We followed the carbon-carbon bond dissociation and the structural opening of the 1,3-cyclohexadiene ring by the direct measurement of time-dependent changes in the distribution of interatomic distances. We observed a substantial acceleration of the ring-opening motion after internal conversion to the ground state due to a steepening of the electronic potential gradient towards the product minima. The ring-opening motion transforms into rotation of the terminal ethylene groups in the photoproduct 1,3,5-hexatriene on the subpicosecond timescale.
Conformational isomers (conformers) of molecules play a decisive role in biology and organic chemistry. However, experimental methods for investigating chemical reaction dynamics are typically not ...conformer-sensitive. We report on a gas-phase megaelectronvolt ultrafast electron diffraction investigation of α-phellandrene undergoing an electrocyclic ring-opening reaction. We directly imaged the evolution of a specific set of α-phellandrene conformers into the product isomer predicted by the Woodward-Hoffmann rules in real space and time. Our experimental results are in quantitative agreement with nonadiabatic quantum molecular dynamics simulations, which provide considerable detail of how conformation influences the time scale and quantum efficiency of photoinduced ring-opening reactions.
Heavy metal-contaminated soil constitutes many environmental concerns. The toxic nature of heavy metals poses serious threats to human health and the ecosystem. Decontamination of the polluted soil ...by phytoremediation is of fundamental importance. Vegetation is an appealing and cost-effective green technology for the large-scale phytoremediation of polluted soils. In this paper, a greenhouse experiment was carried out to test the potential of
as a heavy metal phytoremediator in polluted soil. Plants were grown for three months in pots filled with soils treated with the heavy metals Cd, Pb, Cu, and Zn at rates of 10, 50, and 100 mg/kg. The bioaccumulation factor (BCF) and translocation factor (TF) were calculated to detect the ability of
to accumulate and transfer heavy metals from soil to plant organs. The results showed that under increasing levels of soil pollution, the bioconcentration of Cd and Zn heavy metals showed the highest values in plant roots followed by leaves, whereas in the case of Pb and Cu, roots showed the highest values followed by stems. Heavy metals accumulation was higher in roots than in stems and leaves. The BCF of Zn reached the highest values in roots and stems for 10 mg/kg soil treatment, followed by the BCFs of Cd, Cu, and Pb. The TF for the different heavy metal pollutants' concentrations was less than unity, suggesting that the plants remediate pollutants by phytostabilization. The TF values ranged from higher to lower were in the order Zn > Cu > Cd > Pb. The rapid growth of
and its tolerance of heavy metals, as well as its ability to absorb and accumulate metals within the plant, recommends its use in the phytoremediation of slightly polluted soils in arid lands by limiting the heavy metals transport.
Electrocyclic reactions are characterized by the concerted formation and cleavage of both σ and π bonds through a cyclic structure. This structure is known as a pericyclic transition state for ...thermal reactions and a pericyclic minimum in the excited state for photochemical reactions. However, the structure of the pericyclic geometry has yet to be observed experimentally. We use a combination of ultrafast electron diffraction and excited state wavepacket simulations to image structural dynamics through the pericyclic minimum of a photochemical electrocyclic ring-opening reaction in the molecule α-terpinene. The structural motion into the pericyclic minimum is dominated by rehybridization of two carbon atoms, which is required for the transformation from two to three conjugated π bonds. The σ bond dissociation largely happens after internal conversion from the pericyclic minimum to the electronic ground state. These findings may be transferrable to electrocyclic reactions in general.
Coronavirus disease 2019 (COVID-19) caused a progress in research to find a solution to this pandemic. Also, various advances in pharmacotherapy against COVID-19 have emerged. Regarding antiviral ...therapy, casirivimab and imdevimab are antibodies combination against COVID-19. Standard antiviral therapy against COVID-19 includes remdesivir and favipiravir. The objectives were to compare progression and multi-organ function of hospitalized COVID-19 patients between these three antiviral groups. 265 COVID-19 hospitalized patients were included in this study and were divided into 3 groups (1:2:2), respectively, Group (A): casirivimab and imdevimab, group (B): remdesivir, and group (C): favipiravir. The design of the study is a single blind non-randomized controlled trial. This study is a phase IV clinical trial (post-marketing study). The duration of the study was about 6 months after receiving the ethical approval. Casirivimab and imdevimab achieved less case progression as presented by lower World Health Organization scale (
< 0.05 in comparing group A with B and C) and better multi-organ functions as presented by lower Sequential Organ Function Assessment score (
< 0.05 in comparing group A with B and C) than remdesivir and favipiravir. From all these results, it is concluded that Group A (casirivimab and imdevimab) produces better outcomes than B (remdesivir) and C (favipiravir) intervention groups.
•Corona Virus induced disease – 2019 (COVID-19) disaster motivates scientific research to find a settling to this pandemic.•Various advances in immunotherapy against COVID-19 have ...emerged.•Casirivimab and imdevimab antibody combination is a type of new immunotherapy against COVID-19, Other antiviral therapy against COVID-19 includes Remdesivir and Favipravir.•This research can benefit the covid-19 patients by determining the most appropriate antiviral drug according to the case, This study may change the protocol of treatment of COVID-19 patients.•Casirivimab and imdevimab achieve better clinical outcomes than Remdesivir, and Favipravir.
Corona Virus disease - 2019 (COVID-19) disease induces scientific research to find a control to this pandemic from 2020 year up to now. Recently, various advances in pharmacotherapy against COVID-19 have emerged.
To compare the efficacy and safety of antibodies cocktail (casirivimab and imdevimab), Remdesivir, and Favipravir in the COVID-19 patients
This study is a single-blind non-Randomized Controlled Trial (non-RCT). The drugs of the study are prescribed by lectures on chest diseases, faculty of medicine-Mansoura University. The duration of the study is about six months after ethical approval.
265 hospitalized COVID-19 patients were used to represent the COVID-19 population and were assigned into three groups in a ratio of (1:2:2) respectively, Group (A) received REGN3048–3051(Antibodies cocktail (casirivimab and imdevimab)), group (B) received remdesivir, and group (C) received favipravir.
Casirivimab and imdevimab achieve less 28-day mortality rate, and less mortality at hospital discharge than Remdesivir, and Favipravir.
From all of these results, it is concluded that Group A (Casirivimab & imdevimab) achieves more favorable outcomes than B (Remdesivir) & C (Favipravir) intervention groups.
NCT05502081, 16/08/2022, Clinicaltrials.gov
Irritable bowel syndrome (IBS) is a functional gastrointestinal condition marked by chronic bowel pain or discomfort, as well as changes in abdominal motility. Despite its worldwide prevalence and ...clinical impact, the cause of IBS is unknown. Inflammation could play a fundamental role in the development of IBS. The aim of this study was to examine whether pentoxifylline, a competitive nonselective phosphodiesterase inhibitor, is useful in alleviating abdominal pain in IBS patients treated with mebeverine.
A randomized, controlled, and prospective clinical study that included 50 outpatients who met the inclusion criteria for IBS. Patients are allocated randomly into two groups (n = 25). Group 1 (mebeverine group) received mebeverine 135 mg three times daily (t.i.d) for three months. Group 2 (pentoxifylline group) received mebeverine 135 mg t.i.d and pentoxifylline 400 mg two times daily for three months. Patients were assessed by a gastroenterologist at baseline and three months after the medication had been started. The serum levels of interleukin-6, interleukin-8 and tumor necrosis factor-alpha, fecal Neutrophil Gelatinase Associated Lipocalin (NGAL), and fecal myeloperoxidase were measured at the start and after three months of therapy. The Numeric Pain Rating scale (NRS) was assessed at baseline and after therapy. Results: the pentoxifylline group showed a significant decrease in the level of measured biomarkers and a significant decrease in NRS.
Pentoxifylline could be a promising adjuvant anti-inflammatory drug in the treatment of abdominal pain in IBS patients treated with mebeverine.
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•Irritable Bowel Syndrome is a gastrointestinal condition marked by flatulence, abdominal cramps, and changes in bowel habits.•Low grade mucosal inflammation is proven to be involved in irritable bowel syndrome which leads to release of cytokines.•Pentoxifylline decreases the levels of cytokines by its anti-inflammatory effect and could be a novel adjunctive to antispasmodics in relieving abdominal pains in Irritable Bowel Syndrom.
The excessive use of herbicides is a major cause of many environmental problems. The use of isoproturon herbicide as a weed controller has been a common practice globally. Phytoremediation technology ...can help in cleaning up polluted areas. In this paper the ability of CYP1A2 transgenic A. thaliana plants in the phytoremediation of isoproturon herbicides has been investigated. We tested the capability of P450-1A2 overexpression on the detoxification and degradation of isoproturon. We explored the toxic effect of isoproturon on the plant phenotypic characteristics, including the primary root length, rosette diameter, and fresh, dry weight for transgenic and wild type A. thaliana. The results revealed that no morphological changes appeared on CYP1A2 transgenic plants with a high tolerance to isoproturon herbicide applications either via foliar spraying or supplementation of the growth medium. Deleterious effects were observed on the morphological characteristics of plants of the wild type grown in soil under different treatments with isoproturon. The transgenic A. thaliana plants exhibited a vigorous growth even at high doses of isoproturon treatments. In contrast, the growth of the wild type was significantly impaired with doses above 50 µM isoproturon. The transgenic A. thaliana plants expressing P450-1A2 were able to metabolize the phenylurea herbicide isoproturon. Therefore, this method can be determined as a potential bioremediation agent.
Phytoremediation is increasingly receiving attention as a cost
effective technique that uses plants to remediate contaminants from
wastewater, soil and sediments. In this study, the ability of Typha
...domingensis to uptake heavy metals as well as its potential application
for phytoremediation was assessed. Pollutant elements concentrations
were measured in samples of wastewater, sediments and Typha domingensis
collected from industrial wastewater ponds, El-Sadat city, Egypt. This
study specifically focused on the capacity of Typha domingensis to
absorb and accumulate aluminum, iron, zinc and lead. Results indicated
thatTypha domingensis was capable of accumulating the heavy metal ions
preferentially from wastewater than from sediments. The accumulation of
metals in plant organs attained the highest values in roots, rhizomes
and old leaves. Rhizofiltration was found to be the best mechanism to
explain Typha domingensis phytoremediation capability.
The photo-induced dynamics of
-nitrophenol, particularly its photolysis, has garnered significant scientific interest as a potential source of nitrous acid in the atmosphere. Although the photolysis ...products and preceding photo-induced electronic structure dynamics have been investigated extensively, the nuclear dynamics accompanying the non-radiative relaxation of
-nitrophenol on the ultrafast timescale, which include an intramolecular proton transfer step, have not been experimentally resolved. Herein, we present a direct observation of the ultrafast nuclear motions mediating photo-relaxation using ultrafast electron diffraction. This work spatiotemporally resolves the loss of planarity which enables access to a conical intersection between the first excited state and the ground state after the proton transfer step, on the femtosecond timescale and with sub-Angstrom resolution. Our observations, supported by
multiple spawning simulations, provide new insights into the proton transfer mediated relaxation mechanism in
-nitrophenol.
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