Quantitative analysis of mycoflora on commercial domestic fruits in Japan

A comprehensive and quantitative analysis of the mycoflora on the surface of commercial fruit was performed. Nine kinds of fruits grown in Japan were tested. Overall fungal counts on the fruits ranged from 3.1 to 6.5 log CFU/g. The mean percentages of the total yeast counts were higher than those of molds in samples of apples, Japanese pears, and strawberries, ranging from 58.5 to 67.0%, and were lower than those of molds in samples of the other six fruits, ranging from 9.8 to 48.3%. Cladosporium was the most frequent fungus and was found in samples of all nine types of fruits, followed by Penicillium found in eight types of fruits. The fungi with the highest total counts in samples of the various fruits were Acremonium in cantaloupe melons (47.6% of the total fungal count), Aspergillus in grapes (32.2%), Aureobasidium in apples (21.3%), blueberries (63.6%), and peaches (33.6%), Cladosporium in strawberries (38.4%), Cryptococcus in Japanese pears (37.6%), Penicillium in mandarins (22.3%), and Sporobolomyces in lemons (26.9%). These results demonstrated that the mycoflora on the surfaces of these fruits mainly consists of common pre- and postharvest inhabitants of the plants or in the environment; fungi that produce mycotoxins or cause market diseases were not prominent in the mycoflora of healthy fruits. These findings suggest fruits should be handled carefully with consideration given to fungal contaminants, including nonpathogenic fungi, to control the quality of fruits and processed fruit products.     

Genetic Tuning of Iron Oxide Nanoparticle Size,Shape, and Surface Properties in Magnetospirillum magneticum

Different applications require iron oxide nanoparticles (IONPs) of varying size, shape, crystallinity, and surfaces that can be controlled through the synthesis reaction conditions. Under ambient conditions, Magnetospirillum magneticum AMB-1 builds uniform Fe₃O₄ IONPs with shapes and crystal forms difficult to achieve with chemical synthesis. Genetic engineering can be used to change their properties, but there are few tools to fine-tune expression over a wide range. To this end, ribosome binding sites, minimal constitutive promoters, and inducible systems (IPTG, aTc, and OC6) with large dynamic range are designed. These are used to control M. magneticum genes that affect IONP properties, including size (mamC), morphology (mms6), chain length (mamK), and surface coating (mamC fusions). These systems increase the fraction of IONPs that are less than 30 nm, produce rounded particles, and lead to the production of intracellular chains with 24 or more IONPs. In addition, the R5 peptide from diatoms is found to silica coat the surface of metal oxide nanoparticles (Fe, Ti, Ta, Hf) and can be genetically directed to the IONP surface. This work demonstrates the genetic control of IONP properties, but also highlights the robustness of the system, which complicates genetic engineering to produce radically different particles and structures.     

The difference of PMMA-brush-modification on the oxygen permeable perovskite-type oxides by consisting elements

Oxygen permeation of perovskite-type ceramics consists of three elementary processes: oxygen absorption, bulk oxygen diffusion, and oxygen desorption. In most cases, the rate-determining step is the oxygen diffusion step, and the use of thin films improves the oxygen permeation rate of perovskite-type ceramics. Polymer-brush-modification is a useful technique to produce thin films. Grafted PMMA-brushes exhibit a screening effect for attractive interactions between core ceramic particles, thereby inducing repulsive forces on them. This results in the formation of a densely packed ordered array. Modification of the polymerization-initiator and polymer-brushes should affect the oxygen permeation properties of the ceramic particles, especially surface oxygen adsorption and desorption. In this paper, it is demonstrated that these modifications change the cation chemical states and lower the oxygen desorption rate, while increasing the desorption peak temperature. The surface of La–Sr–Co–Fe perovskite-type oxides was modified only with the polymerization initiator, (2-bromo-2-methyl)propionyloxyhexyltriethoxysilane (BHE) because there is no direct interaction between the polymer-brush and the substrate, while the initiator is directly modified to the substrate. The oxygen desorption behavior of BHE-modified oxides indicates that its oxygen desorption property is impeded without modification with PMMA. The investigation of BHE-modified oxide cation chemical states and oxygen desorption behaviors imply that the BHE-modifying site and change in chemical states have selectivity depending on cation species. Although sintering causes the formation of silicate and ceramic decomposition, this step can eliminate the harmful effects of BHE-modification in total. When conventional La–Sr–Co–Fe perovskite-type ceramics are used, sintering is preferable for the recovery of thin-film surface reactions. However, if we utilize site selectivity of BHE-modification, the harmful effects of those modifications can be avoided by modifying BHE onto sites that hardly participate in surface reactions.     

Economical operation of the C pm control chart for monitoring process capability index

Process capability indices are widely used to provide the evaluation measure of a process. Especially, the process capability index C _pm , which is defined by the range of the process standard specification limits and the deviation from a target value, is called the Taguchi index. Boyles has investigated the statistical characteristics of the estimator $\hat{C}_{pm}$ , and also proposed a technique for the C _pm control chart. Since the process capability index C _pm is based on the concept of the Taguchi’s quality loss, the process capability index C _pm already includes an economical concept. In this article, we evaluate an operating cost consisting of the sampling cost, the sample cost, and the quality loss of failing to detect an out-of-control state when the C _pm control chart is used. Then, we derive an optimal operating plan by sample size and sampling interval in order to minimize the ceiling value of the operating cost based on the min–max criterion.     

Predicting the presence of E. coli in tap water using machine learning in Nepal

Within developing countries, a multitude of problems that affect the water supply process can result in the contamination of water taps. While machine learning applications have become popular for attaining efficient water quality predictions, acquiring the necessary data for modelling for developing countries is challenging. This study constructs water quality prediction models by machine learning with a pseudo-pipeline network to complement the missing data of the water supply process. Using both water source and water tap quality information measured by the Government of Nepal, we apply the three machine learning models: support vector machine (SVM), random forest (RF) and LightGBM. Furthermore, we also apply a traditional statistical method—logistic regression (LR)—to the prediction of the Escherichia coli (E. coli) contamination in water taps. With some input variables (such as the length from the nearest sources) obtained from the pseudo-pipeline network, the results show that SVM has stable and high accuracy for both the 26 cities (70%) and for the 25 cities except for Kathmandu (79%). LR performed a significantly lower accuracy for all cities (61%) than for 25 cities (79%). Additionally, we show that our method can be applied to other regions where a water quality survey has not yet been conducted.     

A novel nanotube of composite of calcium carbonate and calcium sulfate

Nanotube-shaped precursor which is composed of layered structured sodium dodecylsulfate (SDS) calcium carbonate were obtained by titration of an aqueous solution of Na₂CO₃ into an aqueous solution containing CaCl₂ and SDS at 333-335 K. A unit of the repetition of the precursor was about 4 nm. Nanotube-shaped composite which is composed of CaCO₃ and CaSO₄ of 100-200 nm in diameter and 0.5-2 µm in length was obtained from nanotube-shaped precursor composed of layers of CaCO₃ and SDS by calcinations at 673 K in air. The precursor sheet composed of CaCO₃ layers on which SDS molecules attached to both side seemed to curl up and form a pipe.     

Development of a Method for Scaffold-Free Elastic Cartilage Creation

Microtia is a congenital aplasia of the auricular cartilage. Conventionally, autologous costal cartilage grafts are collected and shaped for transplantation. However, in this method, excessive invasion occurs due to limitations in the costal cartilage collection. Due to deformation over time after transplantation of the shaped graft, problems with long-term morphological maintenance exist. Additionally, the lack of elasticity with costal cartilage grafts is worth mentioning, as costal cartilage is a type of hyaline cartilage. Medical plastic materials have been transplanted as alternatives to costal cartilage, but transplant rejection and deformation over time are inevitable. It is imperative to create tissues for transplantation using cells of biological origin. Hence, cartilage tissues were developed using a biodegradable scaffold material. However, such materials suffer from transplant rejection and biodegradation, causing the transplanted cartilage tissue to deform due to a lack of elasticity. To address this problem, we established a method for creating elastic cartilage tissue for transplantation with autologous cells without using scaffold materials. Chondrocyte progenitor cells were collected from perichondrial tissue of the ear cartilage. By using a multilayer culture and a three-dimensional rotating suspension culture vessel system, we succeeded in creating scaffold-free elastic cartilage from cartilage progenitor cells.     

Hop Bitter Acids Increase Hippocampal Dopaminergic Activity in a Mouse Model of Social Defeat Stress

As daily lifestyle is closely associated with mental illnesses, diet-based preventive approaches are receiving attention. Supplementation with hop bitter acids such as iso-α-acids (IAA) and mature hop bitter acids (MHBA) improves mood states in healthy older adults. However, the underlying mechanism remains unknown. Since acute oral consumption with IAA increases dopamine levels in hippocampus and improves memory impairment via vagal nerve activation, here we investigated the effects of chronic administration of hop bitter acids on the dopaminergic activity associated with emotional disturbance in a mouse model of repeated social defeat stress (R-SDS). Chronic administration of IAA and MHBA significantly increased dopaminergic activity based on the dopamine metabolite to dopamine ratio in the hippocampus and medial prefrontal cortex following R-SDS. Hippocampal dopaminergic activity was inversely correlated with the level of R-SDS-induced social avoidance with or without IAA administration. Therefore, chronic treatment with hop bitter acids enhances stress resilience-related hippocampal dopaminergic activity.