Microwave-assisted synthesis for a highly selective rhodamine 6G-derived fluorescent sensor and bioimaging.

A new rhodamine 6G derivative R1 has been synthesized by condensation of rhodamine hydrazide and 6-hydroxymethyl-pyridine using microwave-assisted reaction. Naked-eye colorimetric and photo physical studies show the synthesized compound is selectively sensing Cu2+ in CH3CN/H2O (9:1, v/v) solution. Upon coordination with Cu2+ ion, the spirolactam of R1 is opened, which results in a formation of highly fluorescent complex and change in color of the solution. The Job's plot indicates 1:2 binding stoichiometry between Cu2+ ion and R1. Limit of detection for Cu2+ was determined to be 1.23 µM. The sensor was successfully applied to fluorescent imaging of Cu2+ ion in living cells.

Masking the Peroxidase-Like Activity of the Molybdenum Disulfide Nanozyme Enables Label-Free Lipase Detection.

Two-dimensional MoS2 nanoparticles (2D-nps) exhibit artificial enzyme properties that can be regulated at bio-nanointerfaces. We discovered that protein lipase is able to tune the peroxidase-like activity of MoS2 2D-nps, offering low-nanomolar, label-free detection and identification in samples with unknown identity. The inhibition of the peroxidase-like activity of the MoS2 2D-nps was demonstrated to be concentration dependent, and as low as 5 nm lipase was detected with this approach. The results were compared with those obtained with several other proteins that did not display any significant interference with the nanozyme behavior of the MoS2 2D-nps. This unique response of lipase was characterized and exploited for the successful identification of lipase in six unknown samples by using qualitative visual inspection and a quantitative statistical analysis method. The developed methodology in this approach is noteworthy for many aspects; MoS2 2D-nps are neither labeled with a signaling moiety nor modified with any ligands for signal readout. Only the intrinsic nanozyme activity of the MoS2 2D-nps is exploited for this detection approach. No analytical equipment is necessary for the visual detection of lipase. The synthesis of the water-soluble MoS2 2D-nps is low costing and can be performed in bulk scale. Exploring the properties of 2D-nps and their interactions with biological materials reveals highly interesting yet instrumental features that offer the development of novel bioanalytical approaches.

Decrystallization of Crystals Using Gold "Nano-Bullets" and the Metal-Assisted and Microwave-Accelerated Decrystallization Technique.

Gout is caused by the overproduction of uric acid and the inefficient metabolism of dietary purines in humans. Current treatments of gout, which include anti-inflammatory drugs, cyclooxygenase-2 inhibitors, and systemic glucocorticoids, have harmful side-effects. Our research laboratory has recently introduced an innovative approach for the decrystallization of biological and chemical crystals using the Metal-Assisted and Microwave-Accelerated Evaporative Decrystallization (MAMAD) technique. In the MAMAD technique, microwave energy is used to heat and activate gold nanoparticles that behave as "nano-bullets" to rapidly disrupt the crystal structure of biological crystals placed on planar surfaces. In this study, crystals of various sizes and compositions were studied as models for tophaceous gout at different stages (i.e., uric acid as small crystals (~10-100 µm) and l-alanine as medium (~300 µm) and large crystals (~4400 µm). Our results showed that the use of the MAMAD technique resulted in the reduction of the size and number of uric acid and l-alanine crystals up to >40% when exposed to intermittent microwave heating (up to 20 W power at 8 GHz) in the presence of 20 nm gold nanoparticles up to 120 s. This study demonstrates that the MAMAD technique can be potentially used as an alternative therapeutic method for the treatment of gout by effective decrystallization of large crystals, similar in size to those that often occur in gout.

Discriminating a Single Nucleotide Difference for Enhanced miRNA Detection Using Tunable Graphene and Oligonucleotide Nanodevices.

In this study we have reported our efforts to address some of the challenges in the detection of miRNAs using water-soluble graphene oxide and DNA nanoassemblies. Purposefully inserting mismatches at specific positions in our DNA (probe) strands shows increasing specificity against our target miRNA, miR-10b, over miR-10a which varies by only a single nucleotide. This increased specificity came at a loss of signal intensity within the system, but we demonstrated that this could be addressed with the use of DNase I, an endonuclease capable of cleaving the DNA strands of the RNA/DNA heteroduplex and recycling the RNA target to hybridize to another probe strand. As we previously demonstrated, this enzymatic signal also comes with an inherent activity of the enzyme on the surface-adsorbed probe strands. To remove this activity of DNase I and the steady nonspecific increase in the fluorescence signal without compromising the recovered signal, we attached a thermoresponsive PEGMA polymer (poly(ethylene glycol) methyl ether methacrylate) to nGO. This smart polymer is able to shield the probes adsorbed on the nGO surface from the DNase I activity and is capable of tuning the detection capacity of the nGO nanoassembly with a thermoswitch at 39 °C. By utilizing probes with multiple mismatches, DNase I cleavage of the DNA probe strands, and the attachment of PEGMA polymers to graphene oxide to block undesired DNase I activity, we were able to detect miR-10b from liquid biopsy mimics and breast cancer cell lines. Overall we have reported our efforts to improve the specificity, increase the sensitivity, and eliminate the undesired enzymatic activity of DNase I on surface-adsorbed probes for miR-10b detection using water-soluble graphene nanodevices. Even though we have demonstrated only the discrimination of miR-10b from miR-10a, our approach can be extended to other short RNA molecules which differ by a single nucleotide.

The Role of Adenovirus in Hepatitis of Unknown Etiology Among Children in Turkey, July 2022 to January 2023.

BACKGROUND: In the first half of 2022, the increase in cases of severe acute hepatitis in children with no epidemiological link and unknown cause has aroused concern worldwide. In this study, we aimed to determine the frequency of adenovirus in children with hepatitis of unknown origin in Turkey. METHODS: In this study, which was conducted with the participation of 16 centers from Turkey, between July 2022 and January 2023, 36 pediatric patients under the age of 18 who met the definition of acute hepatitis were included. RESULTS: Twenty (55,6%) of patients were female and 16 (44,4%) were male, with a mean age of 41.55 ± 39.22 (3-192) months. The most common symptoms were fever (66.7%), weakness (66.7%), loss of appetite (66.7%), fatigue (61.1%), vomiting (61.1%), and diarrhea (47.2%). Six (16 %) children had acute hepatic failure. Eight of the 15 children (46%) had respiratory viral infections (rhinovirus/enterovirus, n = 4; rhinovirus + parainfluenza, n = 1; parainfluenza, n = 1, SARS-CoV-2 n = 2). Adenovirus was detected in 16 (44%) patients. Adenovirus and coinfections were detected in 7 patients. History of diarrhea and fatigue in the last month was significantly higher in the adenovirus group ( P = 0.023 and 0.018). One child who had both adenovirus and rhinovirus infection required liver transplantation; all others recovered with supportive care. CONCLUSION: There were no deaths in our series; however, the number of cases, etiology, and severity of the clinical course may have differed between countries owing to differences in case definitions, laboratory facilities, or regional genetic differences.

Congenital Heart Defects and Outcome in a Large Cohort of Down Syndrome: A Single-Center Experience from Turkey.

OBJECTIVE: Congenital heart defects occur in approximately 50% of children with Down syndrome and they contribute considerably to morbidity and mortality. The aim of this study is to investigate the prevalence, classification, and survival of congenital heart defects in Down syndrome. MATERIALS AND METHODS: About 1731 Down syndrome patients who underwent echocardiography between 1986 and 2022 were evaluated. The median follow-up duration was 8.7 years (range 1-35.8 years). Congenital heart defect was grouped as cyanotic and acyanotic. RESULTS: Among the 1731 patients, 52.1% had congenital heart defects. Congenital heart defect was significantly more common in females than males. The most common cardiac defect was ventricular septal defect (35%), followed by atrial septal defect (31.8%), atrioventricular septal defect (23.4%), tetralogy of Fallot (5%), and patent ductus arteriosus (3.6%). In the follow-up, 43.2% of atrial septal defect, 17.8% of ventricular septal defect, and a total of 20% of congenital heart defects were closed spontaneously. About 34.4% of congenital heart defect was corrected by cardiac surgery/intervention. Five-year survival rate was 97.4% in patients without congenital heart defects, whereas it was 95.6% in mild congenital heart defects and 86.1% in moderate to severe congenital heart defects. There was no relationship between consanguinity, parental age, maternal disease, folic acid supplementation before/during pregnancy, gestational age, birth weight, and congenital heart defects. Neuromotor development was similar in patients with and without congenital heart defects. CONCLUSION: We demonstrated that almost half of the patients had congenital heart defects; ventricular septal defect was the most common congenital heart defect type. This study is valuable in terms of the largest single-center study describing the classification, prognostic factors, and survival of Down syndrome patients with congenital heart defect from Turkey.

Growth charts of Turkish children with Down syndrome.

We present growth curves of 1,726 Turkish children with Down syndrome (DS) between 0 and 18 years of age and investigate the factors that affect growth including congenital heart disease (CHD) and hypothyroidism. Longitudinal measurements of height, weight, and head circumference (HC) were assessed and accompanying major malformations were recorded. Growth curves were monitored using Cole's LMS method. The mean birth length was reduced by -0.5 standard deviation (SD) for Turkish standards in both boys and girls. Pubertal growth spurt of the girls with DS started 1 year earlier, their puberty duration was short and pubertal annual growth rate was inadequate, and as a result the final height was -3.06 SD for Turkish standards. Although the age at onset of pubertal growth spurt and puberty duration of the boys were similar to normal population, their pubertal annual growth rate was inadequate; thus the final height was -2.56 SD for Turkish standards. The final weight values were similar to normal population. The mean HC values of DS children were corresponded to -0.9 SD for Turkish standards at birth; however after 6 months values were below -2 SD. The final HC values were -1.02 SD for boys and -2.21 SD for girls for Turkish standards. We observed that weight was decreased in DS children with severe CHD during first 4 years of life. However, there is no statistically significant difference in values of height and head circumference between patients with or without severe CHD group. In addition, hypothyroidism had no effect on growth in DS patients.

Congenital generalized lipodystrophy: The evaluation of clinical follow-up findings in a series of five patients with type 1 and two patients with type 4.

Congenital generalized lipodystrophy (CGL) is a rare disorder characterized by lipoatrophy affecting the face, limbs and trunk, acromegaloid features, hepatomegaly, hypertriglyceridemia, and insulin resistance. The aim of this study is to evaluate the long-term follow-up findings including gastrointestinal and cardiac manifestations of the patients with CGL1 and CGL4, caused by mutations in the AGPAT2 and CAVIN1 genes, respectively. Two patients aged 2 and 9 years with the same biallelic CAVIN1 mutation and five patients aged between 6 months and 11 years 4 months with AGPAT2 mutations have been followed up for 3-9 years. The patients were between 7 and 20 years of age at their last examination. One of the two patients with CGL4 had congenital pyloric stenosis. The other patient with CGL4 have developed recurrent duodenal perforations which have not been reported in CGL patients previously. The pathological examination of duodenal specimens revealed increased subserosal fibrous tissue and absent submucosal adipose tissue. None of the five CGL1 patients had gastrointestinal problems. Two patients with CGL4 developed hypertrophic cardiomyopathy (HCMP) and severe cardiac arrhythmia, only one patient with CGL1 had HCMP. Hyperinsulinemia was detected in one patient with CGL4 and three patients with CGL1, these three CGL1 patients also had acanthosis nigricans. Hepatic steatosis was detected in one patient with CGL4 and two patients with CGL1 by ultrasonography. In conclusion, these findings suggest that CGL4 patients should also be carefully followed up for gastrointestinal and cardiac manifestations.

Metal-Assisted and Microwave-Accelerated Decrystallization of Pseudo-Tophus in Synthetic Human Joint Models.

In this paper, we tested a hypothesis that the metal-assisted and microwave-accelerated decrystallization (MAMAD) technique, based on the combined use of low-power medical microwave heating (MWH) and gold nanoparticles (Au NPs), can be used to decrystallize laboratory-prepared monosodium urate monohydrate crystal aggregate (pseudo-tophus) placed in three-dimensional (3D) synthetic human joint models. To simulate a potential treatment of chronic tophaceous gout using the MAMAD technique, we used three different 3D synthetic human joint models and assessed the percent mass reduction (PMR, i.e., decrystallization) of pseudo-tophus and microwave-induced synthetic skin patch damage after MAMAD sessions (a MAMAD session = 120 s of MWH in the presence of Au NPs). Our three synthetic joint models are: Model 1: Application of seven MAMAD sessions in a closed synthetic joint with a pseudo-bursa containing a pseudo-tophus submerged in a solution of 20 nm Au NPs followed by dehydration of pseudo-tophus after each MAMAD session to assess PMR. Model 2: Application of seven MAMAD sessions in a closed or open synthetic joint with a pseudo-bursa containing a pseudo-tophus submerged in a solution of Au NPs followed by intermittent dehydration of pseudo-tophus after seven MAMAD sessions to assess PMR. Model 3: Application of 18 MAMAD sessions in a rotated closed synthetic joint (three sides are heated separately) with a pseudo-bursa containing a pseudo-tophus submerged in a solution of Au NPs followed by dehydration after every three MAMAD sessions to assess PMR. After a single MAMAD session, pseudo-tophus exposed to MWH and Au NPs had an average PMR of 8.30% (up to an overall PMR of 15%), and microwave-induced damage to the synthetic skin can be controlled by the use of a sacrificial skin sample and by adjusting the duration and the number of the MAMAD sessions. Computational electromagnetic simulations predict a 10% absorption of electric field by the pseudo-tophus placed in the synthetic joint models, which led us to conclude that a medical microwave source with higher power than 20 W can potentially be used with the MAMAD technique.

Individually grown cobalt nanowires as magnetic force microscopy probes.

AC electric fields were utilized in the growth of individual high-aspect ratio cobalt nanowires from simple salt solutions using the Directed Electrochemical Nanowire Assembly method. Nanowire diameters were tuned from the submicron scale to 40 nm by adjusting the AC voltage frequency and the growth solution concentration. The structural properties of the nanowires, including shape and crystallinity, were identified using electron microscopy. Hysteresis loops obtained along different directions of an individual nanowire using vibrating sample magnetometry showed that the magnetocrystalline anisotropy energy has the same order of magnitude as the shape anisotropy energy. Additionally, the saturation magnetization of an individual cobalt nanowire was estimated to be close to the bulk single crystal value. A small cobalt nanowire segment was grown from a conductive atomic force microscope cantilever tip that was utilized in magnetic force microscopy (MFM) imaging. The fabricated MFM tip provided moderate quality magnetic images of an iron-cobalt thin-film sample.

Ultra-Rapid Crystallization of L-alanine Using Monomode Microwaves, Indium Tin Oxide and Metal-Assisted and Microwave-Accelerated Evaporative Crystallization.

The use of indium tin oxide (ITO) and focused monomode microwave heating for the ultra-rapid crystallization of L-alanine (a model amino acid) is reported. Commercially available ITO dots (< 5 mm) attached to blank poly(methyl)methacrylate (PMMA, 5 cm in diameter with 21-well silicon isolators: referred to as the iCrystal plates) were found to withstand prolonged microwave heating during crystallization experiments. Crystallization of L-alanine was performed at room temperature (a control experiment), with the use of two microwave sources: a 2.45 GHz conventional microwave (900 W, power level 1, a control experiment) and 8 GHz (20 W) solid state, monomode microwave source with an applicator tip that focuses the microwave field to a 5-mm cavity. Initial appearance of L-alanine crystals and on iCrystal plates with ITO dots took 47 ± 2.9 min, 12 ± 7.6 min and 1.5 ± 0.5 min at room temperature, using a conventional microwave and focused monomode microwave heating, respectively. Complete evaporation of the solvent using the focused microwaves was achieved in 3.2 ± 0.5 min, which is ~52-fold and ~172-fold faster than that observed at room temperature and using conventional microwave heating, respectively. The size and number of L-alanine crystals was dependent on the type of the 21-well iCrystal plates and the microwave heating method: 33 crystals of 585 ± 137 µm in size at room temperature > 37 crystals of 542 ± 100 µm in size with conventional microwave heating > 331 crystals of 311 ± 190 µm in size with focused monomode microwave. FTIR, optical microscopy and powder X-ray diffraction analysis showed that the chemical composition and crystallinity of the L-alanine crystals did not change when exposed to microwave heating and ITO surfaces. In addition, theoretical simulations for the binding of L-alanine molecules to ITO and other metals showed the predicted nature of hydrogen bonds formed between L-alanine and these surfaces.

Targeted Gene Panel Sequencing for Early-onset Inflammatory Bowel Disease and Chronic Diarrhea.

BACKGROUND: In contrast to adult-onset inflammatory bowel disease (IBD), where many genetic loci have been shown to be involved in complex disease etiology, early-onset IBD (eoIBD) and associated syndromes can sometimes present as monogenic conditions. As a result, the clinical phenotype and ideal disease management in these patients often differ from those in adult-onset IBD. However, due to high costs and the complexity of data analysis, high-throughput screening for genetic causes has not yet become a standard part of the diagnostic work-up of eoIBD patients. METHODS: We selected 28 genes of interest associated with monogenic IBD and performed targeted panel sequencing in 71 patients diagnosed with eoIBD or early-onset chronic diarrhea to detect causative variants. We compared these results to whole-exome sequencing (WES) data available for 25 of these patients. RESULTS: Target coverage was significantly higher in the targeted gene panel approach compared with WES, whereas the cost of the panel was considerably lower (approximately 25% of WES). Disease-causing variants affecting protein function were identified in 5 patients (7%), located in genes of the IL10 signaling pathway (3), WAS (1), and DKC1 (1). The functional effects of 8 candidate variants in 5 additional patients (7%) are under further investigation. WES did not identify additional causative mutations in 25 patients. CONCLUSIONS: Targeted gene panel sequencing is a fast and effective screening method for monogenic causes of eoIBD that should be routinely established in national referral centers.

Microwave Heating of Synthetic Skin Samples for Potential Treatment of Gout Using the Metal-Assisted and Microwave-Accelerated Decrystallization Technique.

Physical stability of synthetic skin samples during their exposure to microwave heating was investigated to demonstrate the use of the metal-assisted and microwave-accelerated decrystallization (MAMAD) technique for potential biomedical applications. In this regard, optical microscopy and temperature measurements were employed for the qualitative and quantitative assessment of damage to synthetic skin samples during 20 s intermittent microwave heating using a monomode microwave source (at 8 GHz, 2-20 W) up to 120 s. The extent of damage to synthetic skin samples, assessed by the change in the surface area of skin samples, was negligible for microwave power of ≤7 W and more extensive damage (>50%) to skin samples occurred when exposed to >7 W at initial temperature range of 20-39 °C. The initial temperature of synthetic skin samples significantly affected the extent of change in temperature of synthetic skin samples during their exposure to microwave heating. The proof of principle use of the MAMAD technique was demonstrated for the decrystallization of a model biological crystal (l-alanine) placed under synthetic skin samples in the presence of gold nanoparticles. Our results showed that the size (initial size ∼850 µm) of l-alanine crystals can be reduced up to 60% in 120 s without damage to synthetic skin samples using the MAMAD technique. Finite-difference time-domain-based simulations of the electric field distribution of an 8 GHz monomode microwave radiation showed that synthetic skin samples are predicted to absorb ∼92.2% of the microwave radiation.

Atomically thin layers of B-N-C-O with tunable composition.

In recent times, atomically thin alloys of boron, nitrogen, and carbon have generated significant excitement as a composition-tunable two-dimensional (2D) material that demonstrates rich physics as well as application potentials. The possibility of tunably incorporating oxygen, a group VI element, into the honeycomb sp(2)-type 2D-BNC lattice is an intriguing idea from both fundamental and applied perspectives. We present the first report on an atomically thin quaternary alloy of boron, nitrogen, carbon, and oxygen (2D-BNCO). Our experiments suggest, and density functional theory (DFT) calculations corroborate, stable configurations of a honeycomb 2D-BNCO lattice. We observe micrometer-scale 2D-BNCO domains within a graphene-rich 2D-BNC matrix, and are able to control the area coverage and relative composition of these domains by varying the oxygen content in the growth setup. Macroscopic samples comprising 2D-BNCO domains in a graphene-rich 2D-BNC matrix show graphene-like gate-modulated electronic transport with mobility exceeding 500 cm(2) V(-1) s(-1), and Arrhenius-like activated temperature dependence. Spin-polarized DFT calculations for nanoscale 2D-BNCO patches predict magnetic ground states originating from the B atoms closest to the O atoms and sizable (0.6 eV < E g < 0.8 eV) band gaps in their density of states. These results suggest that 2D-BNCO with novel electronic and magnetic properties have great potential for nanoelectronics and spintronic applications in an atomically thin platform.

Selective growth of Ge nanowires by low-temperature thermal evaporation.

High-quality single-crystalline Ge nanowires with electrical properties comparable to those of bulk Ge have been synthesized by vapor-liquid-solid growth using Au growth seeds on SiO(2)/Si(100) substrates and evaporation from solid Ge powder in a low-temperature process at crucible temperatures down to 700 °C. High nanowire growth rates at these low source temperatures have been identified as being due to sublimation of GeO from substantial amounts of GeO(2) on the powder. The Ge nanowire synthesis from GeO is highly selective at our substrate temperatures (420-500 °C), i.e., occurs only on Au vapor-liquid-solid growth seeds. For growth of nanowires of 10-20 µm length on Au particles, an upper bound of 0.5 nm Ge deposition was determined in areas of bare SiO(2)/Si substrate without Au nanoparticles.

Hard-disk behavior and beyond in Langmuir films of CdSe nanoparticles.

Harnessing the spontaneous behavior of a population of particles is an attractive approach to the fabrication of targeted nanostructures. Underlying this goal is the interparticle potential, as it dictates the spontaneous behavior of the system. To this end, we present methodology for using quantitative film balance studies of trioctylphosphine oxide (TOPO) stabilized CdSe nanoparticles to determine their effective interparticle potential on the air-water interface. A simple protocol for reducing the quantity of excess TOPO to negligible levels of surface activity is established. In studying clean populations of 2.08, 2.22, 2.36, 2.49, 2.63, and 2.91 nm nanoparticles, quantitative agreement between their pressure-area isotherms and the Carnahan-Starling hard-disk equation of state is achieved. This analysis indicates that CdSe nanoparticles of a given diameter behave how hard disks with significantly smaller diameters would behave. This finding suggests that an attractive contribution to the interparticle potential, such as the dipolar potential, plays a significant role in the spontaneous organization of these particles.

Nanostructured artificial nacre.

Finding a synthetic pathway to artificial analogs of nacre and bones represents a fundamental milestone in the development of composite materials. The ordered brick-and-mortar arrangement of organic and inorganic layers is believed to be the most essential strength- and toughness-determining structural feature of nacre. It has also been found that the ionic crosslinking of tightly folded macromolecules is equally important. Here, we demonstrate that both structural features can be reproduced by sequential deposition of polyelectrolytes and clays. This simple process results in a nanoscale version of nacre with alternating organic and inorganic layers. The macromolecular folding effect reveals itself in the unique saw-tooth pattern of differential stretching curves attributed to the gradual breakage of ionic crosslinks in polyelectrolyte chains. The tensile strength of the prepared multilayers approached that of nacre, whereas their ultimate Young modulus was similar to that of lamellar bones. Structural and functional resemblance makes clay- polyelectrolyte multilayers a close replica of natural biocomposites. Their nanoscale nature enables elucidation of molecular processes occurring under stress.