By the recent fast growth of e-commerce markets, it has been stimulated to study order picking systems to improve their efficiency in distribution centers. Many companies and researchers have been developed various types of order picking systems and pursued the corresponding optimal operation policies. However, the performances of the systems with the optimal policies often depend on the structures of the centers and the operation environments. Based on a simulation model that mimics a unique zone picking system operated by a real company in the Republic of Korea, this study compares several operation policies and finds the most appropriate order selection rule and worker assignment policy for the system. Under all scenarios considered in this study, simulation results show that it is recommendable to assign more efficient workers to the zones with heavier workload. It also shows that selecting the order with the maximum number of non-repeatedly visited zones from the order list provides the most consistent and stable performances with respect to flow time, makespan, and utilization of the system even under the scenario with the breakdown zones. On the other hand, selecting the order with the minimum ratio of penalty to the number of zones performs the worst in all scenarios considered.

Water lettuce (Pistia stratiotes L.) is a free-floating perennial herbaceous plant with rosette leaves and a stem. Although this plant multiplies and has adverse effects on aquatic ecosystems, it can be used for biological purification of polluted water and production of valuable substances as a traditional medicine. In this study, we report a protocol to establish an in vitro micropropagation method based on direct shoot organogenesis from stem explants. In media comprising two types of basal medium and different growth regulators, multiple shoot organogenesis was observed on stems. The micropropagation method was most effective on Schenk and Hildebrandt (SH) medium with 1 mg/L indole-3-acetic acid and 2 mg/L 6-benzylaminopurine supplemented with 30 g/L sucrose, on which all explants produced multiple shoots. The shoots rooted spontaneously on solid half-strength Murashige and Skoog (MS) and SH media without growth regulators (1/2MSO and 1/2SHO). However, roots developed more vigorously in liquid media. Regenerated plants colonized and grew more rapidly in SH basal medium than in MS basal medium and produced 6–8 stolons within 2 weeks on 1/2SHO. In summary, we established a method for micropropagation in vitro through direct organogenesis of water lettuce, which shows the potential of water lettuce as a model aquatic plant for phytochemical and pharmacological research.

Naturally occurring left ventricular hyperplasia is a rare but lethal disease. There are very few reports of this cardiac disease in captive nonhuman primates. In a colony of Macaca mulatta (Rhesus monkey) at California National Primate Research Center, a large number of rhesus macaques were diagnosed by autopsy with naturally occurring left ventricular hypertrophy without obvious underlying diseases over a 22-year period. The confirmatory diagnosis of ventricular hypertrophy was based on findings of notable left ventricular concentric hypertrophy with reduced left ventricular lumen, which is very similar to human ventricular hypertrophy cases. This report discusses an 11-year-old Macaca fascicularis monkey (Cynomolgus monkey, crab-eating macaque), weighing 2.95 kg, that was presented for enrollment in a pharmacokinetic (PK) study. During the PK experiment, the monkey died following a sudden decrease in percutaneous oxygen saturation and heart rate. Gross and histological examinations of the heart were performed. On gross pathology, the left ventricular wall was thickened, and the chamber lumen was reduced. In histopathological examination using hematoxylin- eosin and Masson-trichrome stains, fibrosis and myocyte disarray were not observed, but an increased cell density, compared to the normal heart, was confirmed. The autopsy results confirmed left ventricular hyperplasia as the major cause of death.

The purpose of the study is to assess morphological and chromosomal comparison of Mini type Phalanopsis ‘KS Little Gem’ and four domestic market available cultivars (‘Queen Beer’, ‘Tony Pink’, ‘Vaviche’ and ‘Rorens’). ‘KS Little Gem’ had the highest number of leaves (14.9), while the other four types had fewer than ten. The longest leaf length was 21.5㎝ for ‘Tony Pink’, followed by 16.2㎝, 18.0㎝ and 17.5㎝ for ‘Queen Beer’, ‘Rorens’ and ‘Vaviche’ respectively. The length and width of the petals of ‘KS Little Gem’ were 29.5㎜ and 25.6㎜ respectively indicating a round shape flower compared to other cultivars. When the flower lifespan of ‘KS Little Gem’ was compared to four cultivars of the domestic market, it was found that it had a 123-day shelf life, which was twice longer than that of the four cultivars. According to chromosome analysis ‘KS Little Gem’, ‘Rorens’, ‘Tony Pink,' and ‘Vaviche’ were tetraploid (2n = 4x = 76) while ‘Queen Beer’ was diploid (2n = 2x = 38). The estimated DNA content of ‘KS Little Gem’, ‘Rorens’, ‘Tony Pink’ and ‘Vaviche’ had 4918.4, 4794.2, 4705.2 and 4964.3 Mbp respectively, which were roughly double than that of P. cornu-cervi (control, 2n = 2x = 38). However, ‘Queen Beer’, had an estimated DNA content of 2802.2Mbp, similar to that of P. cornu-cervi. The morphological features, genome size and chromosomal data reported in these studies can be used by breeders to create more efficient Phalaenopsis breeding programs.