Albumin-mediated asymmetric nitroaldol reaction of aromatic aldehydes with nitromethane in water

We succeeded in the asymmetric nitroaldol (Henry) reaction of aromatic aldehydes with nitromethane using human serum albumin (HSA) in water at neutral pH. The reaction of 4-nitrobenzaldehyde smoothly proceeded for 24 h at 30 °C to afford the corresponding (R)-2-nitro-1-(4-nitrophenyl)ethanol (27% ee). Lowering the reaction temperature to 0 °C improved the enantioselectivity (53% ee). Although the denatured HSA also catalyzed the coupling reaction, no enantioselectivity was observed. The reaction was also applicable to other substrates bearing various substitutions on the benzene ring, and the ee of (R)-1-(biphenyl-4-yl)-2-nitroethanol was up to 79% ee.     

In vitro dielectrophoresis of HEK cell migration for stimulating chronic wound epithelialization

This article describes a dielectrophoresis (DEP)-based simulation and experimental study of human epidermal keratinocyte (HEK) cells for wounded skin cell migration toward rapid epithelialization. MyDEP is a standalone software designed specifically to study dielectric particles and cell response to an alternating current (AC) electric field. This method demonstrated that negative dielectrophoresis (N_DEP) occurs in HEK cells at a wide frequency range in highly conductive medium. The finite element method was used to characterize particle trajectory based on DEP and drag force. The performance of the system was assessed using HEK cells in a highly conductive EpiLife suspending medium. The DEP experiment was performed by applying sinusoidal wave AC potential at the peak-to-peak voltage of 10 V in a tapered aluminum microelectrode array from 100 kHz to 1 MHz. We experimentally observed the occurrence of NDEP, which attracted HEK cells toward the local electric field minima in the region of interest. The DIPP-MotionV software was used to track cell migration in the prerecorded video via an automatic marker and estimate the average speed and acceleration of the cells. The results showed that HEK cell migration was accomplished approximately at 6.43 μm/s at 100 kHz with 10 V, and F_DEP caused the cells to migrate and align at the target position, which resulted in faster wound closures because of the application of an electric field frequency to HEK cells in random locations.     

Characterization and cytotoxicity and antihuman renal cell carcinoma potentials of starch capped-copper oxide nanoparticles synthesized by ultrasonic irradiation: Introducing a novel chemotherapeutic drug

In this research article we have demonstrated the sustainable green synthesis of a novel starch templated CuO NP following a clean and non-hazardous pathway. Ultrasonic irradiation was used to promote the reaction in alkaline medium. The numerous hydroxyl groups present in starch was exploited in the green reduction of immobilized copper ions in situ. They also helped to stabilize the as synthesized Cu NPs by encapsulation or capping. The morphology and physicochemical characteristics were ascertained over an array of analytical techniques like Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), Elemental Mapping, Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), and Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). Biologically, the nanocomposite exhibited excellent cytotoxicity against human renal cell carcinoma (RCC-GH, CaKi-2 and HEK293) cell lines without affecting the normal (HUVEC) cell line. IC₅₀ values of the nanocomposite were found at 139, 208and 125 against RCC-GH, CaKi-2 and HEK293 cell lines respectively and accordingly, HEK293 afforded the best adenocarcinoma activity.     

The enormity of the zinc deficiency problem and available solutions; an overview

The societal cost of micronutrient deficiency (MND) or the “hidden hunger” is in millions of dollars/year, reducing the GDP of some countries by as much as 11%. Zn is an important micronutrient for both plants and animals. An estimated 17% of the world population, or around 1.1 billion people, are at the risk of zinc (Zn) deficiency. The deficiency has been related to adverse pregnancy outcomes, stunted growth, premature deaths, immune system dysfunctions, neuro-behavioral disorders, and recently with the failure to recover from COVID-19. These health risks associated with Zn deficiency have compelled FAO and WHO to recommend Zn fortification of diet. Correcting Zn deficiency is a challenge due to several reasons. Close to half of the agricultural soils are Zn deficient, and chemical Zn fertilizers are costly and ineffective. Developing Zn-rich crops through plant breeding and genetic engineering is challenging. Zn-dense diet is costly and cannot be implemented in the low-income region most affected by Zn deficiency. Lack of consensus among regulatory bodies on defining and diagnosing Zn deficiency in plants and Humans. Awareness and other sociocultural issues. Among the most important available solutions are zinc biofortification of the cereal crops, use of zinc biofertilizers, development of Zn-efficient crops with reduced phytate content. The use of Zn supplements, dietary modification, and diversification, especially with fish, are proposed as the most accessible and affordable solutions. Awareness programs in areas suffering the most from Zn deficiency are required. Despite the suggestions from FAO and WHO, global efforts to combat Zn deficiency matching those for combating diseases like HIV are not in place. Coordinated efforts of the international community, especially policy-makers, agricultural scientists, dieticians, physicians, and others, are required to address the issue of hidden hunger.     

A Au nanoparticle and polydopamine co-modified biosensor: A strategy for in situ and label-free surface plasmon resonance immunoassays

This article reports a surface plasmon resonance (SPR) strategy capable of label-free yet amplified in situ immunoassays for sensitive and specific detection of human IgG (hIgG), a serum marker that is important for the diagnosis of certain diseases. Primarily, a wavelength-modulated Kretschman configuration SPR analyzer was constructed, and Au film SPR biosensor chips were fabricated. Specifically, based on Au nanoparticles (AuNPs) adsorbed on the surface of the Au film, the AuNP/Au film was coated with polydopamine (PDA) to fix streptavidin (SA), and then the biotinylated antibodies were connected to the surface of the biosensor chip. The SPR analyzer was utilized for in situ real-time monitoring of hIgG. Due to the immunological recognition between the receptor and target, the surface plasmon waves produced by the attenuated total reflection were affected by the changes in the surface of the biosensor chip. The resonance wavelength (λ_R) of the output spectra gradually redshifted, and the redshift degrees were directly related to the target concentration. The biosensor can realize the in situ detection of hIgG, displaying satisfactory sensitivity, excellent specificity and stability. Briefly, by monitoring the shift in λ_R after specific binding, a new SPR immunoassay can be customized for label-free, in situ and amplified hIgG detection. The operating principle of this research could be extended as a common protocol for many other targets of interest.     

Simultaneous determination of four sedative-hypnotics in human urine based on dendritic structured magnetic nanomaterials

A magnetic solid-phase extraction technique based on magnetic dendritic structured nanoparticles (Fe₃O₄@SiO₂-NH₂-G5) as adsorbent coupled with ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) has been developed to detect diazepam, midazolam, zolpidem, and zaleplon in human urine. With Fe₃O₄@SiO₂-NH₂ as the central core, dendrimer (G5) grafted alternately with cyanuric chloride and imidazole were bonded to the surface of the core to synthesize Fe₃O₄@SiO₂-NH₂-G5. The morphology and structure of the magnetic materials were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and dynamic light scattering (DLS). The key parameters affecting the extraction efficiency were optimized. A satisfactory performance was obtained under the optimum extraction conditions. The proposed method was validated, and the limits of detection of zaleplon, diazepam, zolpidem, and midazolam were 0.05, 0.05, 0.02, and 0.02 ng mL^?1, respectively. The linear correlation coefficients r of the four analytes were > 0.996, the intra-day precision was between 2.4 % and 9.4 % with the recoveries between 88.3 % and 104.8 %, and the inter-day precision ranged from 3.9 % to 15.2 % with the recovery in the range of 94.1 %?108.3 %. The magnetic dendritic structure nanomaterial Fe₃O₄@SiO₂-NH₂-G5 was successfully used to extract sedative-hypnotic drugs from human urine samples. The Fe₃O₄@SiO₂-NH₂-G5-based magnetic solid-phase extraction method eliminates centrifugation and filtration steps as in conventional extraction. Only one step of vortex dispersion extraction could achieve the separation and purification of the target compounds. The proposed method was simple, rapid, environment-friendly, and suitable for the analysis of sedative-hypnotic drugs in human urine.     

Screening of anti-inflammatory and antioxidant potential of functionalized tetrahydrocarbazole linked 1,2-diazoles and their docking studies

Inflammatory diseases are associated with life-threatening syndromes like hepatitis, cancer, and trauma injury while some decrease the quality of life such as rheumatism, arthritis, and tuberculosis. 1,2-Diazoles (pyrazolines) play a vital role in COX-2 inhibition thus dinitro-tetrahydrocarbazole linked pyrazolines have been synthesized and endeavor to screen for anti-inflammatory, antioxidant and molecular docking studies. For this purpose, 6,8-dinitro-acetyl-2,3,4,9-tetrahydrocarbazole (I), aromatic aldehydes (IIa-e) and hydrazines (IIIa-b) were combined via multicomponent reaction approach under the influence of microwave irradiations to afford pyrazolines (1–10). All new molecules were screened for in vitro anti-inflammatory activity by human red blood cells membrane stabilization, antioxidant potential by2,2-diphenyl-1-picrylhydrazyl,2,2´-azinobis (3-ethylbenzo thiazoline)-6-sulphonic acid, lipid peroxidation, and total antioxidant capacity assays along with cytotoxicity by brine shrimp lethality assay. Molecular docking was performed by using the Auto Dock program. Both disubstituted and trisubstituted diazoles showed excellent membrane stabilizing effects, (91.89 % and 77 %, respectively). The presence of phenol, furan, thiocarbamide, and chloro-moieties have the most prominent effect. Toxicity results indicated that compounds were less toxic at the tested dose (0.1 mg/ml). The antioxidant study showed that compound 2 was more active showing low IC₅₀ values (32.2 and 39.2 µg/ml) in DPPH and total phenolic contents assays respectively. Compound 3 (44.0 µg/ml) showed the highest potential assay in ABTS radical neutralization assay while compound 7 (65.0 µg/ml) showed maximum potential in lipid peroxidation. All diazoles (1–10) were screened for in vitro anti-inflammatory potential where disubstituted diazoles were found better than trisubstituted analogs and exhibited significant antioxidant potential. Molecular docking of diazoles showed a good correlation of their anti-inflammatory activity with p38α MAPK, COX-2, and 5-LOX enzymes that are molecular therapeutic targets of inflammation.     

Application of magnetic solid phase extraction in separation and enrichment of glycoproteins and glycopeptides

The analysis of endogenous glycoproteins and glycopeptides in human body fluids is of great importance for screening and discovering disease biomarkers with clinical significance. However, the presence of interfering substances makes the direct quantitative detection of low-abundance glycoproteins and glycopeptides in human body fluids one of the great challenges in analytical chemistry. Magnetic solid phase extraction (MSPE) has the advantages of easy preparation, low cost and good magnetic responsiveness. Magnetic adsorbents are the core of MSPE technology, and magnetic adsorbents based on different functional materials are widely used in the quantitative analysis of glycoproteins and glycopeptides in human body fluids, making it possible to analyze glycoproteins and glycopeptides with low abundance as well as multiple types, which provides a technical platform for screening and evaluating glycoproteins and glycopeptides in body fluids as disease biomarkers. In this paper, we focus on the recent advances in the application of MSPE technology and magnetic adsorbents for the separation and enrichment of glycoproteins and glycopeptides in human body fluids, and the future trends and application prospects in this field are also presented.     

An infrared small target detection algorithm based on high-speed local contrast method

Small-target detection in infrared imagery with a complex background is always an important task in remote sensing fields. It is important to improve the detection capabilities such as detection rate, false alarm rate, and speed. However, current algorithms usually improve one or two of the detection capabilities while sacrificing the other. In this letter, an Infrared (IR) small target detection algorithm with two layers inspired by Human Visual System (HVS) is proposed to balance those detection capabilities. The first layer uses high speed simplified local contrast method to select significant information. And the second layer uses machine learning classifier to separate targets from background clutters. Experimental results show the proposed algorithm pursue good performance in detection rate, false alarm rate and speed simultaneously.