Index-based weather insurances are innovative tools for mitigating weather risks in agriculture. Several donor agencies and development organisations are investing substantially to propagate these ...programmes in developing countries. However, often due to high basis risks, these products mitigate risk only through diversification effect, thereby defeating the intended purpose. Besides, they send confusing messages to the farmers regarding the very concept of insurance. Therefore, this paper investigates the efficiency of two such index-based weather insurances in Philippines, designed to mitigate rice yield loss caused by strong typhoon winds. The insurance products are designed assuming negative linear correlation between wind speed and rice yield. To verify, we used satellite data and GIS tools to tabulate typhoon wind speeds, concurrent crop stage and the subsequent rice yield in five provinces which have both the programmes. Regression analyses and Ramsey RESET tests confirm that rice yield loss is not a function of incident typhoon wind speed, irrespective of the crop stage. Basis risk estimations, based on minimum variance hedging ratio for a risk averse expected utility maximising consumer show that the products entail basis risks of the order of 99%. Typhoons damage all crops, but wind indexed insurance is inadequate when the insured crop has low head weight and is agile like rice, since wind onslaughts do not determine the degree of yield loss. Notably, a thorough burn analysis for basis risk is a necessity before investing time and money implementing index-based weather insurance schemes as a tool for poverty alleviation.
Two copper(II) complexes Cu(Hpmoh)(NO3)(NCS) (1) and Cu(peoh)(N3)2 (2) were designed and synthesized by reaction of Cu(NO3)2·3H2O with hydrazone Schiff base ligands,abbreviated with Hpmoh and Hpeoh. ...Hpmoh and Hpeoh were prepared by condensation reaction of octanoic hydrazide with pyridine-2-carboxyaldehyde and 2-acetylpyridine, respectively. Complexes 1 and 2 were characterized using different analytical techniques such as FT-IR, UV–Vis, IR, EPR and single X-ray diffraction (XRD) analyses as well as computational methods (DFT). The XRD of 1 and 2 shows a mononuclear or a dinuclear structure with the copper(II) centre adopting a slightly distorted square pyramidal geometry. In water-containing solution and in DMSO, 1 and 2 undergo a partial transformation with formation of Cu(Hpmoh)(NO3)(NCS) (1) and Cu(Hpmoh)(NO3)(H2O/DMSO) (1a) in one system and Cu(peoh)(N3) (2a) in the other one, as supported by DFT calculations. Docking simulations confirmed that the intercalation is the preferred binding mode with DNA for 1, 1a and 2a, but suggested that the minor groove binding is also possible. A significant fluorescence quenching of the DNA–ethidium bromide conjugate was observed upon the addition of complexes 1 and 2 with a quenching constant around 104 M−1 s−1. Finally, both 1 and 2 were examined for anti-cancer activity using MDA-MB-231 (human breast adenocarcinoma) and A375 (malignant melanoma) cell lines through in vitro MTT assay which suggest comparable cancer cell killing efficacy, with the higher effectiveness of 2 due to the dissociation into two Cu(peoh)(N3) units.
The synthesis and characterization of two new mononuclear and dinuclear copper(II) complexes with hydrazone Schiff base ligands were reported. Both of them bind to calf thymus-DNA with an intercalative binding and show high cytotoxicity against MDA-MB-231 (human breast adenocarcinoma) and A375 (malignant melanoma) cell lines. Display omitted
•Two copper(II) complexes with hydrazone Schiff base ligands were studied.•One mononuclear and one dinuclear Cu(II) species were characterized.•Dinuclear complex dissociate into two monomeric Cu(II) moieties in solution.•Both the complexes show interaction with CT-DNA.•Both the complexes are active against MDA-MB-231 and A375 cell lines.
Cover Image Banerjee, Sanchita; Ghosh, Prosenjit; Pramanik, Chirantan ...
Rapid communications in mass spectrometry,
30 November 2020, Letnik:
34
Journal Article
Recenzirano
The cover image is based on the Research Article Fractionation of stable oxygen and clumped isotopes during acid digestion of calcite in the presence of an external direct current electric field by ...Sanchita Banerjee et al., https://doi.org/10.1002/rcm.8921.
Colorectal cancer (CRC) is the third most diagnosed and second leading cause of cancer-related death worldwide. Limitations with existing treatment regimens have demanded the search for better ...treatment options. Different phytochemicals with promising anti-CRC activities have been reported, with the molecular mechanism of actions still emerging. This review aims to summarize recent progress on the study of natural phenolic compounds in ameliorating CRC using in vivo models. This review followed the guidelines of the Preferred Reporting Items for Systematic Reporting and Meta-Analysis. Information on the relevant topic was gathered by searching the PubMed, Scopus, ScienceDirect, and Web of Science databases using keywords, such as "colorectal cancer" AND "phenolic compounds", "colorectal cancer" AND "polyphenol", "colorectal cancer" AND "phenolic acids", "colorectal cancer" AND "flavonoids", "colorectal cancer" AND "stilbene", and "colorectal cancer" AND "lignan" from the reputed peer-reviewed journals published over the last 20 years. Publications that incorporated in vivo experimental designs and produced statistically significant results were considered for this review. Many of these polyphenols demonstrate anti-CRC activities by inhibiting key cellular factors. This inhibition has been demonstrated by antiapoptotic effects, antiproliferative effects, or by upregulating factors responsible for cell cycle arrest or cell death in various in vivo CRC models. Numerous studies from independent laboratories have highlighted different plant phenolic compounds for their anti-CRC activities. While promising anti-CRC activity in many of these agents has created interest in this area, in-depth mechanistic and well-designed clinical studies are needed to support the therapeutic use of these compounds for the prevention and treatment of CRC.
Collision tumours, characterized by the simultaneous occurrence of two distinct neoplasms within the same anatomical site, are exceedingly rare in oral pathology. This case report presents an ...uncommon collision tumour involving desmoplastic ameloblastoma and squamous odontogenic tumour in the anterior maxilla of a 52-year-old male from the Indian population. Desmoplastic ameloblastoma is a variant of ameloblastoma known for its unique histopathological features, while squamous odontogenic tumour is a benign epithelial odontogenic tumour with distinctive clinical behaviour. The rarity of this occurrence emphasizes the need for accurate diagnosis and effective treatment strategies. This report discusses the clinical presentation, radiographic findings, and histopathological characteristics of this collision tumour. Through the presentation of this case, we aim to contribute to the understanding of these rare entities and their management considerations.
In the current article, a substrate engineered patterned array of square-shaped features of size 1.5 μm × 1.5 μm comprising of /100-planes of p-Si substrate has been developed by employing electron ...beam lithography assisted selective anisotropic wet etching. The etching of such planes is performed by combining the effect of KOH as the chemical etchant and Pt/Pt3Si as the mask with its catalyzing properties for the etching reaction. The regular array of exposed /100-planes is confirmed by FESEM imaging and X-ray diffraction study. The formation of a ‘virtual hetero-junction’ at /100 interface is characterized by in-situ current-voltage measurement within the FESEM chamber. Such surface engineered Si-substrates can be utilized for multifaceted applications by fabricating different types of electronic, optoelectronic and bio-sensing devices.
•A substrate engineered sub-μm patterned array of square groves of -planes on a 100-Si substrate is fabricated.•The patterning is performed by electron beam lithography-assisted selective anisotropic wet etching.•KOH etching of Si substrate is patterned and catalyzed by developing a Pt/Pt3Si nano-porous mask.•The Si < 111>/100 ‘virtual hetero-junction’ is explored by in-situ electrical measurement within the FESEM chamber.•Such surface engineered Si-substrates can be utilized as a template for electronic, optoelectronic and bio-sensing devices.
Rationale
In ‘clumped isotope paleothermometry’ carbonates are reacted with anhydrous phosphoric acid to extract CO2 that carries the isotopic signature of the reacting carbonates, and the amount of ...clumping in the product CO2 is measured. Previous theoretical models for determining clumped isotopic fractionation in product CO2 during acid digestion of carbonates are independent of the cations present in the carbonate lattice. Hence further study is required to understand the cationic effect.
Methods
We studied the acid reaction mechanism based on the protonation of carbonates, calculated the acid fractionation factor for dolomite using the partition functions and vibrational frequencies obtained for the transition state structure, and determined the effect of cations on the acid fractionation factor. Experimentally, carbonates are reacted using the modified sealed vessel method and analyzed in the dual inlet of a ThermoFinnigan MAT 253 isotope ratio mass spectrometer.
Results
The oretically obtained acid fractionation factor can be expressed as Δ47 acid fractionation in dolomite = −0.28563 + 0.49508 * (105/T2) − 0.08231 * (105/T2)2 for a temperature range between 278.15 and 383.15 K. The theoretical slope of the dolomite–acid digestion curve is lower than that of the calcite–acid digestion curve obtained using the identical reaction mechanism. Our theoretical slope is consistent with the result from the common acid bath experiments but higher than the slope obtained in our experimental study using the modified sealed vessel method and in a previous theoretical study using the H2CO3 model.
Conclusions
The transition state structure, obtained in our study, includes the cations present in the carbonate minerals and provides distinct acid fractionation factors for calcite and dolomite. The observed gentler slope of the theoretically calculated dolomite–acid digestion curve than of the calcite curve is expected considering the stronger Mg–O bond. Our experimental approach invokes post‐digestion isotopic exchange and agrees with the previous theoretical estimates where post‐digestion isotopic fractionation was considered.
Rationale
Phosphoric acid digestion of carbonate generates CO2 for stable oxygen and clumped isotope analysis using a gas source isotope ratio mass spectrometer. The initial step of the digestion ...reaction is protonation of calcite while the product CO2 equilibrates with the system allowing further exchange of isotopes to various extents depending on the nature of the acid digestion methods. An external electric field is introduced in the break seal method to demonstrate the role of the protonation reaction and the post‐digestion isotopic exchanges in the final isotopic composition of product CO2.
Methods
An acid digestion experiment following the break seal method was conducted at a constant temperature of 25 ± 0.5°C in the presence of a uniform external electric field of 0.5 kV/cm within a specially fabricated corona chamber. Replicate samples of a calcite powder of a reference standard (MAR J1) were reacted for 24 h in the presence and absence of an external electric field for varying exposure times (6 to 24 h) and the evolved CO2 was analyzed using a dual‐inlet MAT 253 isotope ratio mass spectrometer.
Results
The CO2 yield from the phosphoric acid digestion of MAR J1 calcite was 20% lower during the reaction in presence of an electric field for an exposure time of 24 h, while the corresponding δ18O value and Δ47 composition were 0.3‰ and 0.1‰ less, respectively, than without any electric field.
Conclusions
We documented the systematic control of oxygen and clumped isotope ratios in CO2 evolved from the carbonate acid digestion reaction with varying exposure time to the external electric field. We provide a new method involving use of an external electric field to manipulate the isotopic fractionation during the acid digestion reaction of calcite. The experimental observation enabled theoretical understanding of the reaction mechanism of carbonate with phosphoric acid which will be useful for stable and clumped isotope studies.
