Combined Forward-Backward Asymmetry Measurements in Top-Antitop Quark Production at the Tevatron

The CDF and D0 experiments at the Fermilab Tevatron have measured the asymmetry between yields of forward- and backward-produced top and antitop quarks based on their rapidity difference and the asymmetry between their decay leptons. These measurements use the full data sets collected in proton-antiproton collisions at a center-of-mass energy of $\sqrt s =1.96$ TeV. We report the results of combinations of the inclusive asymmetries and their differential dependencies on relevant kinematic quantities. The combined inclusive asymmetry is $A_{\mathrm{FB}}^{t\bar{t}} = 0.128 \pm 0.025$. The combined inclusive and differential asymmetries are consistent with recent standard model predictions

Silica micro/nanospheres for theranostics: from bimodal MRI and fluorescent imaging probes to cancer therapy

Nano-theranostics offer remarkable potential for future biomedical technology with simultaneous applications for diagnosis and therapy of disease sites. Through smart and careful chemical modifications of the nanoparticle surface, these can be converted to multifunctional tiny objects which in turn can be used as vehicle for delivering multimodal imaging agents and therapeutic material to specific target sites in vivo. In this sense, bimodal imaging probes that simultaneously enable magnetic resonance imaging and fluorescence imaging have gained tremendous attention because disease sites can be characterized quick and precisely through synergistic multimodal imaging. But such hybrid nanocomposite materials have limitations such as low chemical stability (magnetic component) and harsh cytotoxic effects (fluorescent component) and, hence, require a biocompatible protecting agent. Silica micro/nanospheres have shown promise as protecting agent due to the high stability and low toxicity. This review will cover a full description of MRI-active and fluorescent multifunctional silica micro/nanospheres including the design of the probe, different characterization methods and their application in imaging and treatment in cancer

Antibody-conjugated nanoparticles for target-specific drug delivery of chemotherapeutics

Nanotechnology provides effective methods for precisely delivering chemotherapeutics to cancer cells, thereby improving efficacy and reducing off-target side effects. The targeted delivery of nanoscale chemotherapeutics is accomplished by two different approaches, namely the exploitation of leaky tumor vasculature (EPR effect) and the surface modification of nanoparticles (NPs) with various tumor-homing peptides, aptamers, oligonucleotides, and monoclonal antibodies (mAbs). Because of higher binding affinity and specificity, mAbs have received a lot of attention for the detection of selective cancer biomarkers and also for the treatment of various types of cancer. Antibody-conjugated nanoparticles (ACNPs) are an effective targeted therapy for the efficient delivery of chemotherapeutics specifically to the targeted cancer cells. ACNPs combine the benefits of NPs and mAbs to provide high drug loads at the tumor site with better selectivity and delivery efficiency. The mAbs on the NP surfaces recognize their specific receptors expressed on the target cells and release the chemotherapeutic agent in a controlled manner. Appropriately designed and synthesized ACNPs are essential to fully realize their therapeutic benefits. In blood stream, ACNPs instantly interact with biological molecules, and a protein corona is formed. Protein corona formation triggers an immune response and affects the targeting ability of the nanoformulation. In this review, we provide recent findings to highlight several antibody conjugation methods such as adsorption, covalent conjugation, and biotin–avidin interaction. This review also provides an overview of the many effects of the protein corona and the theranostic applications of ACNPs for the treatment of cancer

Conjugates of calixarenes emerging as molecular entities of nanoscience

Calixarenes, along with cyclodextrins (viz. β-CD) and crown ethers, are the most commonly studied macrocyclic compounds. These bucket shaped molecules have gained tremendous importance for having both hydrophilic and hydrophobic compartments together in the same species. The primary target of this review is to give the readers of various disciplines an updated overview of the recent advancements of the conjugates of calixarenes with respect to their nano chemistry in understanding the nanoscience of these supramolecular systems. Calixarenes now compete with cyclodextrins and calixresorcinols. Thus it is important to look into the current advancement in the literature to draw appropriate comparisons and to provide appropriate designs for their nano science aspects. This review is expected to provide all this. The review covers over 113 conjugates of calixarenes published in 106 references that include contributions from our research group. All the conjugates and their nanoscience aspects were depicted through 63 figures and two schemes. The characterization of these nano systems has been carried out by a variety of techniques that includes spectroscopy and microscopy. The advancement of the conjugates of calixarenes in the nanoworld can be considered as one of the most recent encroachment in the calixarene chemistry and is expected to come out as a major thrust research area in near future

1,3-Di-peptido-conjugates of calix[4]arene and its di-OCH₃ derivatives: Synthesis, characterization and phosphate recognition

1098-1108Novel double-armed peptido-conjugates of calix[4]arene have been developed on the lower rim of the macrocycle. The functional group pendants exhibit conformational bend through the involvement of 11-atom N-H…O hydrogen bond inscribed in a 14-atom O-H…O interaction. As a result, only the terminal -COOR and -COOH groups are exposed to the environment, but not the amide moiety. The cone-conformation of the calix[4]arene is further stabilized through the O-H…O interactions at the lower rim. In effect, the conjugates exhibit a binding core at the lower rim along with hydrophobic cavity formed by the enclosure of arene moieties. Conformational mobility induced by the replacement of lower rim phenolic–OH by –OCH3 has also been demonstrated by variable temperature NMR studies in case of the corresponding –OCH3 derivatives. Differential receptor binding characteristics of these conjugates towards phosphate are demonstrated using absorption spectroscopy. The negatively charged phosphate group is received preferentially by the carboxylic terminal over the ester terminal conjugate

Lower rim 1,3-di{bis(2-picolyl)}amide derivative of calix[4]arene (L) as ratiometric primary sensor toward Ag<SUP>+</SUP> and the complex of Ag<SUP>+</SUP> as secondary sensor toward cys: experimental, computational, and microscopy studies and INHIBIT logic gate properties of L

A structurally characterized lower rim 1,3-di{bis(2-picolyl)}amide derivative of calix[4]arene (L) exhibits high selectivity toward Ag+ by forming a 1:1 complex, among nine other biologically important metal ions, viz., Na+, K+, Mg2+, Ca2+, Mn2+, Fe2+, Co2+, Ni2+, and Zn2+, as studied by fluorescence, absorption, and 1H NMR spectroscopy. The 1:1 complex formed between L and Ag+ has been further proven on the basis of ESI mass spectrometry and has been shown to have an association constant, Ka, of 11117 ± 190 M-1 based on fluorescence data. L acts as a primary ratiometric sensor toward Ag+ by switch-on fluorescence and exhibits a lowest detectable concentration of 450 ppb. DFT computational studies carried out in mimicking the formation of a 1:1 complex between L and Ag+ resulted in a tetrahedral complex wherein the nitrogens of all four pyridyl moieties present on both arms are being coordinated. Whereas these pyridyls are located farther apart in the crystal structure, appropriate dihedral changes are induced in the arms in the presence of silver ion in order to form a coordination complex. Even the nanostructural features obtained in TEM clearly differentiates L from its Ag+ complex. The in situ prepared silver complex of L detects Cys ratiometrically among the naturally occurring amino acids to a lowest concentration of 514 ppb by releasing L from the complex followed by formation of the cysteine complex of Ag+. These were demonstrated on the basis of emission, absorption, 1H NMR, and ESI mass spectra. The INH logic gate has also been generated by choosing Ag+ and Cys as input and by monitoring the output signal at 445 nm that originates from the excimer emission of L in the presence of Ag+. Thus L is a potential primary sensor toward Ag+ and is a secondary sensor toward Cys

Fluorescence switch-on sensor for Cu2+ by an amide linked lower rim 1,3-bis(2-picolyl)amine derivative of calix[4]arene in aqueous methanol

A highly selective fluorescence switch on sensor, L for detecting Cu2+ has been synthesized by introducing a bis-(2-picolyl)amine moiety at the lower rim of a calix[4]arene platform via amide linkage. Binding properties of L toward ten different biologically relevant Mn+ ions have been studied by fluorescence and absorption spectroscopy in methanol and aqueous methanol. L was found to detect Cu2+ selectively down to a concentration of 196 and 341 ppb, respectively, in methanol and 1:1 aqueous methanol even in the presence of other metal ions. The composition of the complex has been found to be 1:1 based on the Job plot and is further confirmed by ESI MS. The role of calix[4]arene platform as well as the pre-organized binding core in the selective recognition of Cu2+ has been demonstrated by studying appropriate reference molecules. The possible modes of binding of L with Cu2+ have been modeled by computational calculations. L and its Cu2+ complex could very well be differentiated based on the nano-structural features observed in SEM and AFM.© Elsevie

Charged Gold Nanoparticles Promote In Vitro Proliferation in <i>Nardostachys jatamansi</i> by Differentially Regulating Chlorophyll Content, Hormone Concentration, and Antioxidant Activity

Nardostachys jatamansi is a critically endangered medicinal plant and endemic to the Himalayas, having high commercial demand globally. The accumulation of various secondary metabolites in its shoots and roots with antioxidant potential are well-documented in traditional as well as modern medicine systems. In the present study, we first attempted to investigate the impact of citrate (−ve charge, 11.1 ± 1.9 nm) and CTAB (+ve charge, 19.5 ± 3.2 nm) coated gold nanoparticles (AuNPs) on the in vitro proliferation and antioxidant activities of N. jatamansi. Both the nanoparticles differentially affected the morphological and biochemical parameters, chlorophyll content, internal hormone concentration, and antioxidant activities in a concentration-dependent (10–100 µM) manner. Vigorous shooting was observed in half strength MS medium supplemented with IAA (1 mg/L) with 60 µM citrate-AuNPs (46.4 ± 3.7 mm) and 40 µM CTAB-AuNPs (42.2 ± 3.2 mm). Similarly, the maximum number of roots (5.00 ± 0.67 and 5.33 ± 0.58) and root length (29.9 ± 1.5 mm and 27.3 ± 4.8 mm) was reported in half-strength MS medium with IAA (1 mg/L) supplemented with 60 µM citrate-AuNPs and 40 µM CTAB-AuNPs, respectively. In addition, plants growing on MS medium supplemented with 60 µM citrate-AuNPs and 40 µM CTAB-AuNPs showed significantly enhanced photosynthetic pigments (chlorophyll a and b, carotenoids, and total chlorophyll), internal hormone concentration (GA3, IAA, and ABA), and antioxidant activities (total phenolics, flavonoids, DPPH, and SOD enzyme activity). Moreover, the transcript analysis of ANR1, ARF18, PLY9, SAUR28, GID1A, GRF1, SOD, and CAT further confirmed the role of 60 µM citrate-AuNPs and 40 µM CTAB-AuNPs in the improvement in the growth and antioxidant activities of N. jatamansi. Bearing in mind the urgent requirements of the effective conservation measures of this endangered species, the present findings suggest the elicitation of citrate-AuNPs and CTAB-AuNPs would significantly improve the potential applications of N. jatamansi in the medicinal plant-based industry

A Theragnosis Probe Based on BSA/HSA-Conjugated Biocompatible Fluorescent Silicon Nanomaterials for Simultaneous in Vitro Cholesterol Effluxing and Cellular Imaging of Macrophage Cells

Fluorescent silicon NPs (Si-NPs) and 3-mercaptopropionic acid-coated CdS NPs (MPA-NPs) were prepared and conjugated with two different albumin proteins, viz., BSA (B) and HSA (H). The absorption, fluorescence, FTIR, circular dichroism, and gel electrophoresis studies confirmed the conjugation of proteins to NPs. DPPH assay confirmed that the conjugated proteins retained their functional activity even after chemical modifications. The sizes of Si-NPs by TEM were found to be ∼8.7 ± 2 nm, whereas MPA-NPs showed individual particle sizes of ∼4.6 ± 1 nm. The in vitro studies suggested that these NPs were highly biocompatible. The potential of these protein-conjugated NPs in cholesterol effluxing and fluorescence imaging was studied using two different macrophage cell lines, viz., human coronary artery endothelial cells (HCAEC) and human umbilical vein endothelial cells (HUVEC). Results suggested that HSA-conjugated NPs showed better cholesterol effluxing ability and superior penetration toward these treated cells. Intracellular presence of Si-NPs was confirmed by confocal microscopic studies. All these studies unravelled the potential of Si-NPs as a theragnosis probe for future biomedical applications