ABSTRACT
This study explores the potential of untapped lithium hydroxide (LiOH) as a phase change material for thermal energy storage. By overcoming the challenges associated with the liquid LiOH leakage, we successfully thermal-cycled LiOH in a laboratory scale experimentation, and observed its stability (>500 thermal cycles), without chemical decomposition. This step has never been performed to date. Its solid-to-liquid reversible transitions temperatures and related solidification/melting enthalpies values have been verified. Then, the first experimental characterization of LiOH's thermal properties shows unexpected values for its heat capacity, thermal conductivity and diffusivity, in contradiction with the few ones available in literature. This opens avenues for LiOH's applications for the storage of sensible and latent heat, as shown through the increased cycle efficiency potential of a thermal energy storage system if based on its energy storage capacity; up to six times more volumetric energy density compared to traditional Solar Salt-based systems used in the solar tower plant (4.5 GJ/m3 vs. 0.76 GJ/m3 over 1000 thermal cycles). Additionally, we observed a softening phenomenon that occurs inconsistently during heating, but which may account for its excellent melting properties and the interplay with other raw chemicals. This new insight contributes certainly to the underlying mechanisms in the synthesis of another promising heat storage material in development: the peritectic compound Li4Br(OH)3. This pioneering work suggests LiOH as a promising ultra-compact thermal energy storage material for filling the intermediary gap from current to next-generation solar power plants, although its large-scale application requires further investigation to achieve economic viability.
ABSTRACT
OBJECTIVES: The aim of this study was to test the null hypothesis that there is no difference in the alveolar bone thickness, bone loss or incidence of fenestrations between upper and lower incisors in skeletal Class I bidentoalveolar protrusive patients before orthodontic treatment. METHODS: Three-dimensional (3D) cone beam CT (CBCT) images were taken of 24 patients from the Republic of Korea (17 females and 7 males). Reformatted CBCT images were used to measure labial and lingual alveolar bone thickness (ABT) of the 4 upper incisors and 4 lower incisors of the 24 patients (total n = 192 incisors) at every 1/10 of root length (Level 0, cementoenamel junction (CEJ) area; Level 10, root apex area) as well as alveolar bone area (ABA) and alveolar bone loss (%BL) rate to dental root length. The numbers of fenestration teeth were also tallied. RESULTS: All anterior teeth were supported by <1 mm of ABT on the labial surfaces up to root length Level 8. ABA was statistically greater on the lingual aspect than the labial aspect in lower incisors. The %BL was 26.98% in the lower labial region, 19.27% in upper labial aspect and most severe on the lower lingual plate 31.25% compared with the labial plate. There were no significant differences in %BL between subgroups when categorized by sex or age. Fenestrations were 1.37 times more frequent on lower incisors (37) than upper incisors (27). CONCLUSION: The null hypothesis was rejected, confirming that incisor periodontal support is poor and alveolar bone loss is severe even prior to the start of orthodontic treatment. Careful diagnosis using 3D CBCT images is needed to avoid iatrogenic degeneration of periodontal support around anterior teeth, particularly in the lower lingual bone plate region.
Subject(s)
Alveolar Bone Loss/diagnostic imaging , Cone-Beam Computed Tomography , Imaging, Three-Dimensional , Incisor/diagnostic imaging , Malocclusion, Angle Class I/diagnostic imaging , Malocclusion, Angle Class I/therapy , Orthodontics, Corrective , Adolescent , Adult , Bone Density , Cephalometry , Chi-Square Distribution , Child , Female , Humans , Incisor/abnormalities , Male , Retrospective StudiesABSTRACT
Although previous studies demonstrated that genistein-induced apoptosis of various cell types including RPE-J cells, the involvement of mitochondrial events in such types of apoptosis has not been demonstrated to date. In this investigation of genistein-induced apoptosis of RPE-J cells, genistein induced the reduction of the mitochondrial membrane potential and the release of cytochrome c to cytosol. A mitochondrial permeability transition pore (PTP) blocker bongkrekic acid prevented the reduction of the mitochondrial membrane potential and cytochrome c release, and consequently abolished caspase-3 activation, nuclear condensation, and DNA fragmentation. On the other hand, zVAD-fmk did not inhibit the mitochondrial event such as the reduction of the mitochondrial membrane potential and cytochrome c release although it prevented caspase-3 activation, nuclear condensation, and DNA fragmentation. Taken together, genistein induces apoptosis of RPE-J cells by opening the mitochondrial PTP, and the mitochondrial event in this type of apoptosis is caused independently of caspase.
Subject(s)
Apoptosis/drug effects , Apoptosis/physiology , Enzyme Inhibitors/pharmacology , Genistein/pharmacology , Ion Channels , Membrane Proteins/physiology , Mitochondria/physiology , Animals , Cell Line , Cell Membrane Permeability , Membrane Potentials/drug effects , Mitochondria/drug effects , Mitochondria/ultrastructure , Mitochondrial Membrane Transport Proteins , Mitochondrial Permeability Transition PoreABSTRACT
New tetrakis(multifluoro-4-pyridyl)porphin derivatives (2-4) and water soluble porphyrin (5) were synthesized to investigate their interactions with acetylcholinesterase from electric eel. These compounds have been found to be the potent reversible inhibitors of the enzyme with Ki values of microM range. In addition, porphyrin (5) showed broad spectrum of anticancer activities.
Subject(s)
Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/pharmacology , Cholinesterase Inhibitors/chemical synthesis , Porphyrins/chemical synthesis , Porphyrins/pharmacology , Animals , Antineoplastic Agents/chemistry , Cholinesterase Inhibitors/chemistry , Cholinesterase Inhibitors/pharmacology , Drug Design , Drug Screening Assays, Antitumor , HL-60 Cells , Humans , Kinetics , Melanoma, Experimental , Molecular Structure , Porphyrins/chemistryABSTRACT
We report the synthesis of (+/-)-3,6-Di-O-valproil-1,2:4,5-di-O-isopropylidene-myo-inositol (5) as well as (+/-)-3,6-Di-O-valproil-4,5-O-isopropylidene-myo-inositol (6) and (+/-)-3,6-Di-O-valproil-myo-inositol (7), which results from acid hydrolysis of the formers. The anticonvulsant activity of the compound 7 (MES test) expressed as ED50 is four times higher than that reported for valproic acid.
Subject(s)
Anticonvulsants/chemical synthesis , Anticonvulsants/pharmacology , Prodrugs/chemical synthesis , Prodrugs/pharmacology , Valproic Acid/pharmacology , Animals , Blood-Brain Barrier/drug effects , Electroshock , Inositol/chemical synthesis , Inositol/chemistry , Magnetic Resonance Spectroscopy , Mice , Postural Balance/drug effects , Valproic Acid/analogs & derivativesABSTRACT
The authors investigated the efficacy of antibiotic irrigation as the therapeutic option in congenital nasolacrimal duct obstruction. We retrospectively reviewed the medical record of 76 patients' eyes in whom congenital nasolacrimal duct obstruction had been diagnosed. In 50 of these patients, the colonizing microorganism was identified and, irrigation through canaliculi was performed using antibiotics of suitable sensitivity. Nasolacrimal system probing was performed on 26 patients as the control group. Treatment was regarded successful when over a 4 week period epiphora or mucous discharge disappeared and when saline passed without resistance on irrigation. 96.0% of patients in the irrigation group and 84.6% of patients in probing group were treated successfully. There was no statistical difference in the success rate between the two groups (P = 0.173). The recovery period based on culture results was 3.22 +/- 0.37 months in the group in which microorganisms were isolated and 2.39 +/- 0.35 months in the group in which no organisms were isolated. There were no statistically significant differences in the success rates between the group in which there was growth and the group in which there was no growth (P = 0.1308). Thus a similar result was obtained using nasolacrimal probing and canaliculus antibiotic irrigation in congenital nasolacrimal duct obstruction. Antibiotic irrigation is a safe and simple therapeutic option in congenital nasolacrimal duct obstruction.
Subject(s)
Dacryocystorhinostomy , Lacrimal Duct Obstruction/congenital , Nasolacrimal Duct/surgery , Ophthalmologic Surgical Procedures , Anti-Bacterial Agents/administration & dosage , Female , Humans , Infant , Male , Retrospective Studies , Therapeutic Irrigation/methods , Treatment OutcomeABSTRACT
PURPOSE: To separate and characterize the different positional isomers of mono-PEGylated salmon calcitonins (mono-PEG-sCTs) and to evaluate the effects of the PEGylation site on the stability of different mono-PEG-sCTs in rat kidney homogenate. METHODS: Mono-PEG-sCTs were prepared using succinimidyl carbonate monomethoxy polyethylene glycol (5,000 Da) and separated by gel-filtration HPLC followed by reversed-phase HPLC. To characterize PEGylated sCTs, matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) and reversed-phase HPLC of the trypsin digested samples were performed. Mono-PEG-sCTs and sCT in rat kidney homogenates were measured by column-switching reversed-phase HPLC with on-line detection of the radioiodinated samples using a flow-through radioisotope detector. RESULTS: Three different mono-PEGylated sCTs were separated by reversed-phase gradient HPLC. From the MALDI-TOF MS analysis, the average molecular weight of mono-PEG-sCTs was confirmed as around 8650 Da. The presence of PEG moiety in the mono-PEG-sCTs was also manifested by the fact that the distance between two adjacent mass spectum lines was 44 Da which corresponds to PEG monomer unit. Tryptic digestion analysis demonstrated that these mono-PEG-sCTs are 3 positional isomers of N-terminus, Lys18- and Lys11-residue modified mono-PEGylated sCTs. The degradation half-life of these 3 positional isomers in rat kidney homogenates significantly increased in order of the N-terminus (125.5 min), Lys11- (157.3 min), and Lys18 residue modified mono-PEGylated sCT (281.5 min) over the native sCT (4.8 min). CONCLUSION: Three positional isomers of mono-PEGylated sCTs were purified and characterized. Of these, the resistance to proteolytic degradation was highest for the Lys18-residue modified mono-PEG-sCT. These studies demonstrate that the in vivo stability of PEGylated sCTs is highly dependent on the site of PEG molecule attachment.
Subject(s)
Calcitonin/isolation & purification , Amino Acid Sequence , Animals , Calcitonin/chemistry , Calcitonin/metabolism , Chromatography, High Pressure Liquid , In Vitro Techniques , Mass Spectrometry , Molecular Sequence Data , Protein Isoforms/chemistry , Protein Isoforms/isolation & purification , Protein Isoforms/metabolism , Rats , SalmonABSTRACT
The present study was aimed at evaluating the treatment changes of anterior open bite malocclusion cases treated by means of the Multiloop Edgewise Arch Wire technique, which is considered one of the more effective treatment modalities for anterior open bite malocclusions. The open bite sample was composed of 16 young adults, 4 males and 12 females. The normal occlusion sample, as a controlled sample was composed of 58 young adults who had pleasing facial profiles and normal occlusions with no experience of orthodontic or prosthodontic treatment. The normal sample was subdivided by the cephalometric vertical facial relationships. Forty adults with cephalometric vertical facial relationships within the normal range of Korean standards were classified as Normal Occlusion Group 1. Eighteen adults with an increased vertical facial relationship but with normal occlusion, were classified as Normal Occlusion Group 2. Thirty-nine reference points were digitized on each film, and the computerized cephalometric analysis was obtained with 8 skeletal, 10 dentoalveolar, 17 teeth angulations, and 4 occlusal plane measurements. Treatment changes were determined by the paired t test, and the structural differences between the four groups were tabulated by the Student's t test. The treatment changes were observed mainly in the dentoalveolar region in the upper and the lower occlusal planes, accompanied by the uprighting of the posterior teeth to the occlusal plane through the distal tipping movement of the entire dentition. After the treatment, there was a tendency for the structural feature of the open bite group to approximate those of the normal occlusion group 2. This ascertains that the treatment changes of open bite malocclusion produced by means of the multiloop edgewise arch wire technique are similar to those found in the natural dentoalveolar compensatory mechanism.
Subject(s)
Malocclusion/therapy , Orthodontics, Corrective/methods , Adolescent , Adult , Case-Control Studies , Cephalometry , Evaluation Studies as Topic , Female , Humans , Incisor , Male , Orthodontic Wires , Outcome Assessment, Health Care , Reference Values , Vertical DimensionABSTRACT
In this study, the degradation of Octastatin, a cyclic octapeptide analog of somatostatin, was examined as a function of pH, temperature, buffer, and ionic strength by reversed-phase gradient high-performance liquid chromatography. Degradation of Octastatin followed a first-order kinetics. Various buffer species such as acetate, ammonium acetate, citrate, glutamate, phosphate, and borate showed differing effects on the degradation of the octapeptide. Good stability was found in glutamate and acetate buffer of pH 4.0. Degradation of Octastatin was greater in citrate- or phosphate-containing buffers than in glutamate or acetate buffers. With phosphate buffer, higher buffer concentration caused greater degradation, while in acetate buffer, the effect of buffer concentration and ionic strength was negligible. In addition, the degradation of Octastatin was markedly inhibited by increasing the concentration of glutamate buffer. This study allows the prediction of good stability in acetate buffer (0.01 M, pH 4.0) with a t90% of 84.1 days at 20 degrees C.