Correction to "Direct Visualization of Crystalline Domains in Carboxylated Nanocellulose Fibers".

[This corrects the article DOI: 10.1021/acsomega.0c00410.].

Sulphur-doped graphene quantum dot based fluorescent turn-on aptasensor for selective and ultrasensitive detection of omethoate.

Development of selective, ultra-sensitive, rapid and facile methods for the detection of chemical residues of toxic pesticides and hazardous chemicals are quite important in food safety, environmental monitoring and safeguarding public health. Herein, we presented a fluorescent turn-on aptasensor based on sulphur-doped graphene quantum dot (S-GQD) utilizing specific recognition and binding property of aptamer for the ultra-sensitive and selective detection of omethoate (OM) which is a systemic organophosphorus pesticide. The detection method is based on tuning aggregation-disaggregation mechanism of S-GQD by way of conformational alteration of the recognition probe. Fluorescence 'turn-on' process includes aggregation-induced quenching of S-GQD with aptamer via S-GQD-aptamer complex formation and its subsequent fluorescence recovery with the addition of OM by structural switching of S-GQD-aptamer complex to aptamer-omethoate complex. The reported 'switch-on' aptasensor has exhibited a low limit of detection of 0.001 ppm with high selectivity for OM over other pesticides.

Direct Visualization of Crystalline Domains in Carboxylated Nanocellulose Fibers.

Direct visualization of soft organic molecules like cellulose is extremely challenging under a high-energy electron beam. Herein, we adopt two ionization damage extenuation strategies to visualize the lattice arrangements of the ß-(1→4)-d-glucan chains in carboxylated nanocellulose fibers (C-NCFs) having cellulose II crystalline phase using high-resolution transmission electron microscopy. Direct imaging of individual nanocellulose fibrils with high-resolution and least damage under high-energy electron beam is achieved by employing reduced graphene oxide, a conducting material with high electron transmittance and Ag+ ions, with high electron density, eliminating the use of sample-specific, toxic staining agents, or other advanced add-on techniques. Furthermore, the imaging of cellulose lattices in a C-NCF/TiO2 nanohybrid system is accomplished in the presence of Ag+ ions in a medium revealing the mode of association of C-NCFs in the system, which validates the feasibility of the presented strategy. The methods adopted here can provide further understanding of the fine structures of carboxylated nanocellulose fibrils for studying their structure-property relationship for various applications.

Total CD3 T Cells Are Necessary and Sufficient to Induce Colitis in Immunodeficient Mice With Dendritic Cell-Specific Deletion of TGFbR2: A Novel IBD Model to Study CD4 and CD8 T-Cell Interaction.

BACKGROUND: Inflammatory bowel disease (IBD) is a multifactorial disorder, with the innate and adaptive immune cells contributing to disease initiation and progression. However, the intricate cross-talk between immune cell lineages remains incompletely understood. The role of CD8+ T cells in IBD pathogenesis has been understudied, largely due to the lack of appropriate models. METHODS: We previously reported spontaneous colitis in mice with impaired TGFß signaling due to dendritic cell-specific knockout of TGFbR2 (TGFßR2ΔDC). Here, we demonstrate that crossing TGFßR2ΔDC mice with a Rag1-/- background eliminates all symptoms of colitis and that adoptive transfer of unfractionated CD3+ splenocytes is sufficient to induce progressive colitis in Rag1-/-TGFßR2ΔDC mice. RESULTS: Both CD4+ and CD8+ T cells are required for the induction of colitis accompanied by activation of both T-cell lineages and DCs, increased expression of mucosal IFNγ, TNFα, IL6, IL1ß, and IL12, and decreased frequencies of CD4+FoxP3+ regulatory T cells. Development of colitis required CD40L expression in CD4+ T cells, and the disease was partially ameliorated by IFNγ neutralization. CONCLUSIONS: This novel model provides an important tool for studying IBD pathogenesis, in particular the complex interactions among innate and adaptive immune cells in a controlled fashion, and represents a valuable tool for preclinical evaluation of novel therapeutics.

Delta-like Protein 3 Prevalence in Small Cell Lung Cancer and DLL3 (SP347) Assay Characteristics.

CONTEXT.­: Delta-like protein 3 (DLL3) is a protein that is implicated in the Notch pathway. OBJECTIVE.­: To present data on DLL3 prevalence in small cell lung cancer and staining characteristics of the VENTANA DLL3 (SP347) Assay. In addition, the assay's immunoreactivity with other neoplastic and nonneoplastic tissues is outlined. DESIGN.­: Individual formalin-fixed, paraffin-embedded specimens of small cell lung cancer and tissue microarrays comprising neoplastic and nonneoplastic tissues were procured. Sections were cut and stained with DLL3 (SP347) assay. The slides were examined to determine prevalence, staining characteristics, and immunoreactivity. RESULTS.­: Cytoplasmic and/or membranous staining was observed in 1040 of 1362 specimens of small cell lung cancer (76.4%). Homogenous and/or heterogeneous and partial and/or circumferential granular staining with varied intensities was noted. Immunoreactivity was also observed in other neoplastic and nonneoplastic tissues. CONCLUSIONS.­: Our study findings provided the profile of DLL3 staining characteristics that can be used for determining the level of DLL3 expression in small cell lung cancer.

Rapid, Acid-Free Synthesis of High-Quality Graphene Quantum Dots for Aggregation Induced Sensing of Metal Ions and Bioimaging.

Graphene quantum dots (GQDs) are zero-dimensional materials that exhibit characteristics of both graphene and quantum dots. Herein, we report a rapid, relatively green, one-pot synthesis of size-tunable GQDs from graphene oxide (GO) by a sonochemical method with intermittent microwave heating, keeping the reaction temperature constant at 90 °C. The GQDs were synthesized by oxidative cutting of GO using KMnO4 as an oxidizing agent within a short span of time (30 min) in an acid-free condition. The synthesized GQDs were of high quality and exhibited good quantum yield (23.8%), high product yield (>75%), and lower cytotoxicity (tested up to 1000 µg/mL). Furthermore, the as-synthesized GQDs were demonstrated as excellent fluorescent probes for bioimaging and label-free sensing of Fe(III) ions, with a detection limit as low as 10 × 10-6 M.

Demystifying the mesiobuccal root of maxillary first molar using cone-beam computed tomography.

CONTEXT: Imaging techniques and endodontics are inseparable from each other as the former have always been the cornerstone for successful endodontic diagnosis and treatment. AIMS: The objective of this study was to detect the presence of extra canals in the mesiobuccal root of the maxillary first molar using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: In this study, 75 freshly extracted human maxillary first molars were mounted on arches and exposed to CBCT and digital radiography (control). The incidence of additional canals is then evaluated using CBCT and the teeth identified with additional canals were marked and again exposed to RVG. STATISTICAL ANALYSIS USED: The results were analyzed by three examiners two endodontists and an oral radiologist to eliminate bias. Inter and intra rater agreement was analyzed using the kappa coefficient. RESULTS: Statistical analysis revealed the incidence of extra canals to be at 47.1% with the difference between the readings of the 3 examiners being statistically insignificant. CONCLUSIONS: CBCT can be considered an advanced diagnostic tool for primary and secondary endodontic treatments.

Selective photothermal efficiency of citrate capped gold nanoparticles for destruction of cancer cells.

Gold nanoparticles are recently having much attention because of their increased applications in biomedical fields. In this paper, we demonstrated the photothermal efficacy of citrate capped gold nanoparticles (AuNPs) for the destruction of A431 cancer cells. Citrate capped AuNPs were synthesized successfully and characterized by UV-visible-NIR spectrophotometry and High Resolution Transmission Electron Microscopy (HR-TEM). Further, AuNPs were conjugated with epidermal growth factor receptor antibody (anti-EGFR) and applied for the selective photothermal therapy (PTT) of human epithelial cancer cells, A431. PTT experiments were conducted in four groups, Group I--control cells, Group II--cells treated with laser light alone, Group III--cells treated with unconjugated AuNP and further laser irradiation and Group IV--anti-EGFR conjugated AuNP treated cells irradiated by laser light. After laser irradiation, cell morphology changes that were examined using phase contrast microscopy along with the relevant biochemical parameters like lactate dehydrogenase activity, reactive oxygen species generation and caspase-3 activity were studied for all the groups to determine whether cell death occurs due to necrosis or apoptosis. From these results we concluded that, these immunotargeted nanoparticles could selectively induce cell death via ROS mediated apoptosis when cells were exposed to a low power laser light.

Cellular uptake and subcellular localization of highly luminescent silica-coated CdSe quantum dots--in vitro and in vivo.

With excellent optical properties, quantum dots (QDs) have been made as attractive molecular probes for labeling cells in biological research. The purpose of the present work is to explore the possible role of silica-coated cadmium selenide (CdSe) QDs in the in vitro and in vivo cellular uptake and their subcellular localization. The in vitro uptake characteristics of silica-coated CdSe QDs were performed in cultured New Zealand rabbit adipose tissue-derived mesenchymal stem cells (RADMSCs) and Human cervical cancer cells (HeLa) using fluorescence microscopy after staining with 4,6-diamidino-2-phenylindole (DAPI). The in vitro results showed that the silica-coated CdSe QDs were efficiently taken up by the cells and it was localized in the intracellular vesicles giving strong fluorescence from the cytoplasm and nearby nucleus. Subsequently, the in vivo localization and distribution of QDs were studied by the hematoxilin stained semithin cryosections of tissues (~15 µm thickness) under fluorescence microscopy and ultrathin sections of tissues (~100 nm thickness) under confocal laser scanning microscopy at the distribution maxima. Our in vivo results confirmed the effective cellular uptake and even distribution pattern of QDs in tissues. Overall, these in vitro and in vivo results are represented with focus on internalization, subcellular localization and distribution of the QDs, in view of their potential applications in biomedical field.

Fluorescence imaging of stem cells, cancer cells and semi-thin sections of tissues using silica-coated CdSe quantum dots.

Trioctylphosphine oxide capped cadmium selenide quantum dots, synthesized in organic media were rendered water soluble by silica overcoating. Silanisation was done by a simple reverse microemulsion method using aminopropyl silane as the silica precursor. Further, the strong photoluminescence of the silica-coated CdSe quantum dots has been utilized to visualize rabbit adipose tissue-derived mesenchymal stem cells (RADMSCs) and Daltons lymphoma ascites (DLA) cancerous cells in vitro. Subsequently the in vivo fluorescence behaviours of QDs in the tissues were also demonstrated by intravenous administration of the QDs in Swiss albino mice. The fluorescence microscopic images in the stem cells, cancer cells and semi-thin sections of mice organs proved the strong luminescence property of silica-coated quantum dots under biological systems. These results establish silica-coated CdSe QDs as extremely useful tools for molecular imaging and cell tracking to study the cell division and metastasis of cancer and other diseases.

Biokinetics and in vivo distribution behaviours of silica-coated cadmium selenide quantum dots.

Recently, quantum dots derived from trace elements like cadmium and selenium have attracted widespread interest in biology and medicine. They are rapidly being used as novel tools for both diagnostic and therapeutic purposes. In this report, we evaluated the distribution of silica-coated cadmium selenide (CdSe) quantum dots (QDs) following intravenous injection into male Swiss albino mice as a model system for determining tissue localization using in vivo fluorescence and ex vivo elemental analysis by inductively coupled plasma optical emission spectroscopy (ICP-OES). Trioctylphosphine oxide-capped CdSe quantum dots were synthesized and rendered water soluble by overcoating with silica, using aminopropyl silane (APS) as silica precursor. ICP-OES was used to measure the cadmium content to indicate the concentration of QDs in blood, organs and excretion samples collected at predetermined time intervals. Meanwhile, the distribution and aggregation state of QDs in tissues were also investigated in cryosections of the organs by fluorescence microscopy. We have demonstrated that the liver and kidney were the main target organs for QDs. Our systematic investigation clearly shows that most of the QDs were metabolized in the liver and excreted via faeces and urine in vivo. A fraction of free QDs, maintaining their original form, could be filtered by glomerular capillaries and excreted via urine as small molecules within 5 days.

A rare syndrome of central diabetes insipidus with spastic cerebellar ataxia.

The syndrome of central diabetes insipidus (cDI) and spastic cerebellar ataxia is rare with only a few reports in the literature. We report the case of a 21-year-old patient who was diagnosed to have central diabetes insipidus at the age of 7 years and presented to us at the age of 21 years with progressive spastic cerebellar ataxia that evolved over four years. His MRI showed normal hyperintense signal from the posterior pituitary. The persistence of posterior pituitary signal in patients with cDI is unusual and is observed in the familial variety of cDI, the possible etiology in our patient. A brief review of the literature on the rare syndromic association of cerebellar ataxia and cDI has been discussed.

Hallerborden Spatz disease.

Hallervorden Spatz disease is a rare disorder characterized by progressive extrapyramidal dysfunction. We report a case of a 18 year old boy who presented with cervical dystonia, pigmentary retinal degeneration and MRI brain showing the "eye-of-the-tiger" appearance. Renamed recently as "Neurodegeneration with brain iron accumulation", we present this case for its rarity and interesting features.

The effects of thyroxine treatment on slow- and fast-contracting skeletal muscle contractions of the cat and their cyclic AMP level.

1. The effects of thyroxine treatment on soleus and extensor digitorum longus (EDL) muscle contractions and their cyclic adenosine 3',5'-monophosphate (cyclic AMP) levels were examined in anaesthetized cats. 2. Thyroxine treatment decreased the tension of incomplete tetanic contractions of the soleus as well as the EDL muscles. The effect on tension of these muscles was not associated with an increase in the cyclic AMP level of the muscle as is the case with a beta 2-adrenoceptor agonist effect. 3. The results do not support the involvement of cyclic AMP in the tension depressant effect of thyroxine on contractions of skeletal muscle. 4. It is suggested that the muscle weakness and tremor observed in thyrotoxicosis and during administration of beta 2-adrenoceptor agonists are mediated by different mechanisms.