Analysis of online food purchasing behavior: a study of Sri Lankan consumers

Peer reviewedPublisher PD

Enhancing photoluminescence quantum efficiency of metal halide perovskites by examining luminescence-limiting factors

Metal halide perovskites (MHPs) show superior optoelectronic properties, which give them the great potential for use in next generation light-emitting diodes (LEDs). In particular, their narrow emission linewidths can achieve ultrahigh color purity. However, the reported luminescence efficiency (LE) values are not high enough to be commercialized in displays and solid-state lightings. Moreover, the operational stability of LEDs associated with the overshooting of luminance and the high relative standard deviation of reported external quantum efficiencies are still problematic. In this perspective, we review photophysical factors that limit the photoluminescence quantum efficiency of perovskite-based LEDs. These factors are categorized into (i) weak exciton binding, (ii) nonradiative recombinations, (iii) slow cooling of long-lived hot carriers, (iv) deep-level defects, and (v) interband transition rates. We then present various physicochemical methods to effectively overcome these luminescence-limiting factors. We finally suggest some useful research directions to further improve the LE of MHP emitters as core components in displays and solid-state lightings.

부정교합이 성인 여자대학생의 자존감에 미치는 영향

Objective: The purpose of this study was to evaluate the effects of malocclusion on the self-esteem of female university students. Methods: The subjects were composed of 67 female university students who showed Class I molar relation, no missing or supernumerary teeth and has had no orthodontic treatment experience. Each subject was evaluated with Rosenberg`s Self-esteem Scale to measure the level of self-esteem and also evaluated the degree of anterior crowding and lip protrusion through model analysis and cephalometric soft tissue profile analysis. Results: The results showed that a protrusive profile and crowding of upper anterior teeth had significant reducing effects on the level of self-esteem. The protrusion and crowding groups showed no significant differences in self-esteem between groups. Conclusions: Malocclusion had significant negative effects on the self-esteem of female university students. Further research to investigate the negative psychological influence of malocclusion and the education of lay people about this influence is necessary. (Korean J Orthod 2008;38(6):388-396)이 논문은 2007년도 교정학회 대국민홍보 연구비 지원에 의하여 연구되었음.

Effect of biochars pyrolyzed in N2 and CO2, and feedstock on microbial community in metal(loid)s contaminated soils

Little is known about the effects of applying amendments on soil for immobilizing metal(loid)s on the soil microbial community. Alterations in the microbial community were examined after incubation of treated contaminated soils. One soil was contaminated with Pb and As, a second soil with Cd and Zn. Red pepper stalk (RPS) and biochars produced from RPS in either N2 atmosphere (RPSN) or CO2 atmosphere (RPSC) were applied at a rate of 2.5% to the two soils and incubated for 30 days. Bacterial communities of control and treated soils were characterized by sequencing 16S rRNA genes using the Illumina MiSeq sequencing. In both soils, bacterial richness increased in the amended soils, though somewhat differently between the treatments. Evenness values decreased significantly, and the final overall diversities were reduced. The neutralization of pH, reduced available concentrations of Pb or Cd, and supplementation of available carbon and surface area could be possible factors affecting the community changes. Biochar amendments caused the soil bacterial communities to become more similar than those in the not amended soils. The bacterial community structures at the phylum and genus levels showed that amendment addition might restore the normal bacterial community of soils, and cause soil bacterial communities in contaminated soils to normalize and stabilize

Orthodontic treatment of gummy smile by maxillary total intrusion with a midpalatal absolute anchorage system

This article describes the orthodontic treatment of a 31-year-old Korean female patient with gummy smile and crowding. The patient showed excessive gingival display in both the anterior and posterior areas and a large difference in gingival heights between the anterior and posterior teeth in the maxilla. To correct the gummy smile, we elected to intrude the entire maxillary dentition instead of focusing only on the maxillary anterior teeth. Alignment and leveling were performed, and a midpalatal absolute anchorage system as well as a modified lingual arch was designed to achieve posterosuperior movement of the entire upper dentition. The active treatment period was 18 months. The gummy smile and crowding were corrected, and the results were stable at 21 months post-treatment.OAIID:oai:osos.snu.ac.kr:snu2013-01/102/0000004298/7SEQ:7PERF_CD:SNU2013-01EVAL_ITEM_CD:102USER_ID:0000004298ADJUST_YN:YEMP_ID:A072100DEPT_CD:852CITE_RATE:.537FILENAME:hongyk-maas-gummy0smile-kjo-2013.pdfDEPT_NM:치의과학과SCOPUS_YN:YCONFIRM:

A Smart Checkpointing Scheme for Improving the Reliability of Clustering Routing Protocols

In wireless sensor networks, system architectures and applications are designed to consider both resource constraints and scalability, because such networks are composed of numerous sensor nodes with various sensors and actuators, small memories, low-power microprocessors, radio modules, and batteries. Clustering routing protocols based on data aggregation schemes aimed at minimizing packet numbers have been proposed to meet these requirements. In clustering routing protocols, the cluster head plays an important role. The cluster head collects data from its member nodes and aggregates the collected data. To improve reliability and reduce recovery latency, we propose a checkpointing scheme for the cluster head. In the proposed scheme, backup nodes monitor and checkpoint the current state of the cluster head periodically. We also derive the checkpointing interval that maximizes reliability while using the same amount of energy consumed by clustering routing protocols that operate without checkpointing. Experimental comparisons with existing non-checkpointing schemes show that our scheme reduces both energy consumption and recovery latency

Magnetic resonance imaging analysis of rotator cuff tear after shoulder dislocation in a patient older than 40 years

Background This study was designed to evaluate characters of the rotator cuff tear (RCT) recognized after primary shoulder dislocation in patients older than 40. Methods From 2008 to 2019, patients who visited two hospitals after dislocation were retrospectively reviewed. Inclusion criteria were patients over 40 who had dislocation, with magnetic resonance imaging (MRI) undergone. Exclusion criteria were patients who lost to follow-up, combined with any proximal humerus fracture, brachial plexus injury, and previous operation or dislocation history in the ipsilateral shoulder. Also patients who had only bankart or bony bakart lesion in MRI were excluded. We evaluated RCTs that were recognized by MRI after the primary shoulder dislocation with regard to tear size, degree, involved tendons, fatty degeneration, the age when the first dislocation occurred, and the duration until the MRI was evaluated after the dislocation. Results Fifty-five RCTs were included. According to age groups, the tear size was increased in coronal and sagittal direction, the number of involved tendons was increased, and the degree of fatty degeneration was advanced in infraspinatus muscle. Thirty-two cases (58.2%) conducted MRI after 3 weeks from the first shoulder dislocation event. This group showed that the retraction size of the coronal plane was increased significantly and the fatty accumulation of the supraspinatus muscle had progressed significantly. Conclusions Age is also a strong factor to affect the feature of RCT after the shoulder dislocation in patients over 40. And the delay of the MRI may deteriorate the degree of tear size and fatty degeneration