Thin silica shell coated Ag assembled nanostructures for expanding generality of SERS analytes.

Surface-enhanced Raman scattering (SERS) provides a unique non-destructive spectroscopic fingerprint for chemical detection. However, intrinsic differences in affinity of analyte molecules to metal surface hinder SERS as a universal quantitative detection tool for various analyte molecules simultaneously. This must be overcome while keeping close proximity of analyte molecules to the metal surface. Moreover, assembled metal nanoparticles (NPs) structures might be beneficial for sensitive and reliable detection of chemicals than single NP structures. For this purpose, here we introduce thin silica-coated and assembled Ag NPs (SiO2@Ag@SiO2 NPs) for simultaneous and quantitative detection of chemicals that have different intrinsic affinities to silver metal. These SiO2@Ag@SiO2 NPs could detect each SERS peak of aniline or 4-aminothiophenol (4-ATP) from the mixture with limits of detection (LOD) of 93 ppm and 54 ppb, respectively. E-field distribution based on interparticle distance was simulated using discrete dipole approximation (DDA) calculation to gain insight into enhanced scattering of these thin silica coated Ag NP assemblies. These NPs were successfully applied to detect aniline in river water and tap water. Results suggest that SiO2@Ag@SiO2 NP-based SERS detection systems can be used as a simple and universal detection tool for environment pollutants and food safety.

The effect of pre-anesthetic administration of dexmedetomidine on the consumption of opioids in postoperative gynecologic patients

BACKGROUND: This study was designed to assess whether pre-anesthetic administration of dexmedetomidine reduces the postoperative consumption of opioids, in patients receiving patient-controlled fentanyl after gynecological laparotomy. METHODS: This was a prospective, randomized, double-blind, controlled study. Ten minutes before induction of anesthesia, 36 patients scheduled for elective gynecological laparotomy were assigned to receive either normal saline (group N) or dexmedetomidine 1 µg/kg (group D). A patient-controlled analgesia (PCA) device was used to administer fentanyl for the postoperative 24 h period. Cumulative fentanyl consumption and pain score were assessed at postoperative 30 min, 6 h and 24 h. Patient's satisfaction for pain control and other side effects (nausea, sedation score) were recorded for all corresponding time points. RESULTS: There was no significant difference between the groups in cumulative fentanyl consumption (Group N: 11.1 ± 3.2 µg/kg, Group D: 10.3 ± 2.9 µg/kg, P value: 0.706). The incidence of side-effects did not differ between the groups. Both groups showed similar blood pressure after anesthesia induction. However, 10 min after anesthesia induction, the heart rates in group D were significantly lower than group N (P = 0.0002). CONCLUSIONS: In patients undergoing gynecological laparotomy, the pre-anesthetic administration of single loading dose dexmedetomidine (1 µg/kg) given 10 min before anesthesia induction did not reduce the PCA consumption of postoperative fentanyl or the pain score.

A Case of Stasis Dermatitis Due to Excessive Weight Gain in a Patient with Peritoneal Dialysis / 대한신장학회잡지

Stasis dermatitis is characterized by hyperpigmented lesions occuring as a result of venous stasis of the lower half of the legs. It is often associated with venous thrombosis, varicose vein, obesity, congestive heart failure. Histopathologic findings include fibrosis, new blood vessel formation, and hemosiderin deposition in dermis layer. We here report a case of stasis dermatitis due to excessive weight gain in a patient with peritoneal dialysis. A 50-year-old man on peritoneal dialysis was admitted with edema and hyperpigmentated lesion on both lower legs. He gained weight of 8 kg for 3 months because of excessive oral intake without ultrafiltration failure. Skin biopsy of the hyperpigmented lesion revealed vascular proliferation, infiltration of inflammatory cells, fibrosis, and hemosiderin deposition in dermis. We started hemodialysis in order to correct weight gain and leg edema. After 3 months later, the skin lesions much improved.