Differential Surface Capping Effects on the Applications of Simple Amino-Acid-Capped ZnS:Mn Nanoparticles.

Water-dispersible ZnS:Mn nanoparticles (NPs) were prepared by capping their surface with simple structured amino acids: l-alanine (Ala), l-glycine (Gly), and l-valine (Val) molecules, which have very similar structures except for the terminal organic functional groups. The detailed characterization works for the prepared colloidal NPs were performed using various spectroscopic methods. In particular, the NPs commonly showed UV/visible absorption peaks around 325 nm and PL emission peaks around 590 nm, corresponding to the wavelength of orange color light. In this study, these amino-acid-capped NPs were applied as optical photosensors in the detection of specific divalent transition metal cations in the same conditions. Consequently, all three NPs showed exclusive fluorescence quenching effects upon the addition of Cu (II) metal ions, whereas their quenching efficiencies were quite different to each other. These experimental results indicated that the Gly-ZnS:Mn NPs (k = 4.09 × 105 M-1) can be the most effective optical photosensor for the detection of Cu2+ ions in water among the three NPs in the same conditions. This study showed that the steric effect of the capping ligand can be one of the key factors affecting the sensor activities of the ZnS:Mn NPs.

Applications of the Water-Dispersible L-Cysteine-Capped ZnS:Mn Nanocrystals as a Selective Photosensor and an Efficient Photocatalyst.

In this study, the ZnS:Mn nanocrystals (NCs) were prepared by capping the NC surface with a conventional amino acid, L-cysteine (Cys) molecules, at an acidic (pH 5) aqueous solution. The optical and physical characterizations of the ZnS:Mn-Cys-pH5 NCs were performed using various spectroscopic methods. For instance, the UV-visible and PL spectra of the ZnS:Mn-Cys-pH5 NCs showed broad peaks at 296 and 586 nm, respectively. The obtained HR-TEM image of the ZnS:Mn- Cys-pH5 NCs product showed spherical particle images with an average size of 6.15 nm in the solid state. In addition, measured surface charge of the colloidal ZnS:Mn-Cys-pH5 NCs using a zeta-PSA spectroscopy was -57.9 mV even at the acidic preparation condition. Therefore, the ZnS:Mn-Cys-pH5 NCs were applied as a photosensor to detect specific transition metal cations. As a result, the ZnS:Mn-Cys-pH5 NCs showed exclusive luminescence quenching effect for Fe(II) ions, which suggested that the ZnS:Mn-Cys-pH5 NCs can be applied as a photo-chemical sensor for Fe2+ ion detection in a practical water sample. The sensing ion selectivity of the ZnS:Mn-Cys-pH5 NCs was completely different comparing to ZnS:Mn NCs surface capped with other amino acids at the same condition. In addition, the catalytic activity of the ZnS:Mn-Cys-pH5 NCs was studied in the degradation reaction of an organic dye (methylene blue) molecule under UV light irradiation.

Extracerebral choroid plexus papilloma in the pharynx with airway obstruction in a newborn: a case report.

BACKGROUND: Choroid plexus papillomas (CPPs) are rare, usually benign, neoplasms originating in the central nervous system. In this study, we present the first case of a giant airway-obstructing CPP in the pharynx of a newborn. CASE PRESENTATION: A cystic mass located in the pharynx was noted in a fetus at the 29th week of gestation. Elective cesarean section was performed at the 38th week of gestation with successful intubation and ex utero intrapartum treatment. On computed tomography, there was a huge airway-obstructing cystic mass in the choana and pharynx. Elective surgery with total excision was performed, and histological examination confirmed the diagnosis of CPP. CONCLUSION: We report the first case of an extracerebral airway-obstructing CPP in the pharynx of a newborn. Radiologic examinations are not enough for the diagnosis of CPPs, and complete excision of the tumor with histological confirmation is indispensable for accurate diagnosis and treatment.

Differential Photosensor Activities for the L-Cysteine and L-Serine Capped ZnS:Mn Nanocrystals in the Detection of Divalent Transition Metal Ions in Aqueous Solution.

Colloidal ZnS:Mn nanocrystals (NCs) were synthesized in water by capping the NC surface with conventional amino acids: L-cysteine (Cys) and L-serine (Ser) molecules, which have very similar structures but different terminal functional groups. The optical properties were investigated by using UV-Visible and photoluminescence (PL) spectroscopy. The PL spectra for both ZnS:Mn-Cys and ZnS:Mn-Ser NCs showed broad emission peaks at 590 nm. The measured average particle size from the high-resolution transmission electron microscopy (HR-TEM) images were 4.38 nm (ZnS:Mn-Cys) and 5.57 nm (ZnS:Mn-Ser), which were also supported by Debye-Scherrer calculations. In addition, the surface charge of the NCs in aqueous solutions were measured using zeta-particle size analyzer spectroscopy, which showed formation of negatively charged surface for the ZnS:Mn-Cys (-43.93 mV) and ZnS:Mn-Ser (-8.21 mV) NCs in water. In this present study those negatively charged NCs were applied as photosensors for the detection of specific divalent transition metal cations in aqueous solution at the same condition. Consequently, the ZnS:Mn-Cys and ZnS:Mn-Ser NCs showed totally different photosensor activities upon the addition of first-row divalent transition metal ions. The former NCs showed luminescence quenching for most added metal ions except for Zn (II) ions; whereas the latter NCs showed exclusive quenching effect for Cu (II) ions at the same conditions. These results suggested that those NCs can be applied as Zn2+ and Cu2+ ion sensors in water.

Photosensor and Photocatalytic Activities of the L-Glycine Capped ZnS:Mn Nanocrystals in Aqueous Solution.

In this study, water-dispersible manganese (II) ion-doped ZnS nanocrystals (ZnS:Mn NCs) were synthesized by capping the surface with L-glycine molecules at various pH conditions. The UV-Visible and solution photoluminescence (PL) spectra showed broad peaks approximately at 330 and 590 nm, respectively. The calculated relative quantum efficiencies were in the range of 4.9∼5.8%, and the average particle sizes measured from the HR-TEM images were about 8 nm. Moreover, the surface charges of the corresponding ZnS:Mn-Gly NCs were determined by the electrophoretic method as: (-)14.8 mV (pH 2), (-)9.5 mV (pH 5), and (-)6.4 mV (pH 10) respectively. The most negatively charged ZnS:Mn-Gly-pH 2 NCs were applied as a fluorescence sensor to detect copper (II) ions in water by an exclusive luminescence quenching effect. In addition, photocatalytic activity of the ZnS:Mn-Gly-pH 2 NCs was also evaluated by measuring the degradation rate of an organic dye (methylene blue, MB) molecule under the UV light irradiation. The ZnS:Mn-Gly-pH 2 NCs showed the photodegradation efficiency of the MB molecule with a pseudo-first-order reaction constant (kobs) of 4.3 × 10-4 min-1, which is higher than those of other amino acids-capped ZnS:Mn NCs at the same conditions.

Expression of Myxovirus Resistance A (MxA) Is Associated with Tumor-Infiltrating Lymphocytes in Human Epidermal Growth Factor Receptor 2 (HER2)-Positive Breast Cancers.

PURPOSE: The prognostic significance of tumor-infiltrating lymphocytes (TILs) has been determined in breast cancers. Interferons can affect T-cell activity through direct and indirect mechanisms. Myxovirus resistance A (MxA) is an excellent marker of interferon activity. Here,we evaluated TILs and MxA expression in human epidermal growth factor receptor 2 (HER2)-positive breast cancers. MATERIALS AND METHODS: Ninety cases of hormone receptor (HR)+/HER2+ tumors and 78 cases of HR-/HER2+ tumors were included. The TILs level was assessed using hematoxylin and eosin-stained full face sections, and MxA expressionwas evaluated by immunohistochemistrywith a tissue microarray. RESULTS: MxA protein expression was significantly higher in tumors with high histologic grade (p=0.023) and high levels of TILs (p=0.002). High levels of TILs were correlated with high histological grade (p=0.001), negative lymphovascular invasion (p=0.007), negative lymph node metastasis (p=0.007), absence of HR expression (p < 0.001), abundant tertiary lymphoid structures (TLSs) around ductal carcinoma in situ (p=0.018), and abundant TLSs around the invasive component (p < 0.001). High levels of TILs were also associated with improved disease-free survival, particularly in HR-/HER2+ breast cancers. However, MxA was not a prognostic factor. CONCLUSION: High expression of MxA in tumor cells was associated with high levels of TILs in HER2-positive breast cancers. Additionally, a high level of TILs was a prognostic factor for breast cancer, whereas the level of MxA expression had no prognostic value.

Syntheses of the Water-Dispersible Glycolic Acid Capped ZnS:Mn Nanocrystals at Different pH Conditions, and Their Aggregation and Luminescence Quenching Effects in Aqueous Solution.

Water-dispersible ZnS:Mn nanocrystals were prepared by capping their surface with polar glycolic acid molecules at three different pH conditions. The produced ZnS:Mn-GA nanocrystals were characterized by XRD, HR-TEM, ICP-AES, and FT-IR spectroscopy. The optical properties were also measured by UV-Visible and room temperature photoluminescence (PL) spectroscopy. In the PL spectra, theses ZnS:Mn-GA nanocrystals showed broad emission peaks around 595 nm, and the calculated relative quantum efficiencies against an organic dye standard were in the range from 2.16 to 5.52%. The measured particle size from the HR-TEM images was about 3.7 nm on average, which were also supported by the calculations with the Debye-Scherrer methods. In addition, the surface charges of the nanocrystals were determined by an electrophoretic method, which showed pH dependent charge values of the nanocrytals: +0.88 mV (pH 2), +0.82 mV (pH 7), and -0.59 mV (pH 12) respectively. In addition, the degrees of aggregation of the nanocrystals in aqueous solutions were determined by a hydrodynamic light scattering method. As a result, formations of micrometer size agglomerates for all the ZnS:Mn-GA nanocrystals in water was observed at room temperature. This was probably caused by intermolecular attraction between the capping molecules. In addition, the ZnS:Mn-GA with the negative surface charge was presumed to be suitable for further coordination to a transition metal ion on the surface of the nanocrystal. As a result, fast luminescence quenching was observed after addition of aqueous solution containing Cu2+ ions.

Application of L-Aspartic Acid-Capped ZnS:Mn Colloidal Nanocrystals as a Photosensor for the Detection of Copper (II) Ions in Aqueous Solution.

Water-dispersible ZnS:Mn nanocrystals (NCs) were synthesized by capping the surface with polar L-aspartic acid (Asp) molecules. The obtained ZnS:Mn-Asp NC product was optically and physically characterized using the corresponding spectroscopic methods. The ultra violet-visible (UV-VIS) absorption spectrum and photoluminescence (PL) emission spectrum of the NCs showed broad peaks at 320 and 590 nm, respectively. The average particle size measured from the obtained high resolution-transmission electron microscopy (HR-TEM) image was 5.25 nm, which was also in accordance with the Debye-Scherrer calculations using the X-ray diffraction (XRD) data. Moreover, the surface charge and degree of aggregation of the ZnS:Mn-Asp NCs were determined by electrophoretic and hydrodynamic light scattering methods, respectively. These results indicated the formation of agglomerates in water with an average size of 19.8 nm, and a negative surface charge (-4.58 mV) in water at ambient temperature. The negatively-charged NCs were applied as a photosensor for the detection of specific cations in aqueous solution. Accordingly, the ZnS:Mn-Asp NCs showed an exclusive luminescence quenching upon addition of copper (II) cations. The kinetic mechanism study on the luminescence quenching of the NCs by the addition of the Cu2+ ions proposed an energy transfer through the ionic binding between the two oppositely-charged ZnS:Mn-Asp NCs and Cu2+ ions.

Cardiac mucosa at the gastroesophageal junction: An Eastern perspective.

AIM: To investigate the nature and origin of cardiac mucosa (CM). METHODS: Biopsy samples from sixty-one individuals were included in this study. The specimens were taken "at", "just below", or "just above" the gastroesophageal junction, including the histologic squamocolumnar junction. Clinical data were obtained by reviewing electronic medical records for each patient. Patients with a history of stomach adenoma or carcinoma and esophageal carcinoma were excluded, and cases that were endoscopically suspicious of Barrett's esophagus or a polyp were also ruled out. Histologic and endoscopic reviews were performed blinded to the patient's clinical data. Histologic evaluation was conducted by two pathologists, and endoscopic review was performed by a endoscopist with wide experience in the field. Histologically, the columnar epithelium of squamocolumnar junction, presence and severity of acute and chronic inflammation, atrophy, intestinal metaplasia, and presence of carditis were evaluated. Endoscopically, reflux esophagitis was evaluated by Los Angeles (LA) classification, hiatal hernias were classified by Hill grade, and gastroesophageal flap valves were assessed. RESULTS: Fifty-nine of the 61 (96.7%) patients were Korean; 65.6% (40/61) of the patients underwent endoscopy according to the schedule of the National Health Insurance Program as a screening inspection. Of these, only 20.0% (8/40) of cases had reflux symptoms. CM was present in 41/61 (67.2%) individuals, and its presence was associated with older age compared to oxyntocardiac mucosa/oxyntic mucosa (60.59 ± 2.02 years vs 51.55 ± 3.35 years; P = 0.018). The presence of CM was associated with endoscopic diagnosis of esophagitis according to the LA classification (P = 0.022). CM was associated with mononuclear cell infiltration and neutrophilic infiltration, which were statistically significant (P = 0.001, and P = 0.004, respectively). The inflammation of CM, "carditis", showed a statistically significant association with endoscopic diagnosis of reflux esophagitis according to the LA classification (P = 0.008). CONCLUSION: CM at the gastroesophageal junction is a common histologic finding in biopsy specimens, though not always present, and associated with gastroesophageal reflux disease and carditis severity.

Surface Properties and Photocatalytic Activities of the Colloidal ZnS:Mn Nanocrystals Prepared at Various pH Conditions.

Water-dispersible ZnS:Mn nanocrystals (NC) were synthesized by capping the surface with mercaptoacetic acid (MAA) molecules at three different pH conditions. The obtained ZnS:Mn-MAA NC products were physically and optically characterized by corresponding spectroscopic methods. The UV-Visible absorption spectra and PL emission spectra showed broad peaks at 310 and 590 nm, respectively. The average particle sizes measured from the HR-TEM images were 5 nm, which were also supported by the Debye-Scherrer calculations using the X-ray diffraction (XRD) data. Moreover, the surface charges and the degrees of aggregation of the ZnS:Mn-MAA NCs were determined by electrophoretic and hydrodynamic light scattering methods, indicating formation of agglomerates in water with various sizes (50-440 nm) and different surface charge values accordingly the preparation conditions of the NCs (-7.59 to -24.98 mV). Finally, the relative photocatalytic activities of the ZnS:Mn-MAA NCs were evaluated by measuring the degradation rate of methylene blue (MB) molecule in a pseudo first-order reaction condition under the UV-visible light irradiation. As a result, the ZnS:Mn-MAA NC prepared at the pH 7 showed the best photo-degradation efficiency of the MB molecule with the first-order rate constant (kobs) of 2.0 × 10-3·min-1.

Development of an automated protein-tyrosine phosphatase 1B inhibition assay and the screening of putative insulin-enhancing vanadium(IV) and zinc(II) complexes.

The inhibition of protein-tyrosine phosphatase 1B (PTP1B) is a potential target for treatment of type 2 diabetes. Vanadium and zinc metal coordinated complexes have insulin-enhancing activities, and while vanadium compounds inhibit PTP1B, little is known on the mode of action of zinc compounds. In this study we developed an automated PTP1B inhibition assay that allows for a rapid assessment of the PTP1B inhibition strength of candidate compounds. Synthetic vanadium(IV) and zinc(II) complexes were evaluated: IC50 values for vanadium complexes ranged from 0.06 to 0.8 microM whereas for zinc compounds, values were above 10 microM. Vanadium sulfate, a non-conjugated inorganic salt, had stronger inhibition activity than any of the conjugated metal complexes.