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Recent studies report that surfaces displaying micrometer-or nanometer-sized undulating structures exhibit antibacterial effects. In previous work, we described the use of an advanced nanofabrication technique to generate an artificial biomimetic moth-eye film by coating a polyethylene terephthalate (PET) film with nanoscale moth-eye protrusions made from a hydrophilic resin. This moth-eye film exhibited enhanced antibacterial effects in in vitro experiments. The aim of the present study was to verify the antibacterial efficacy of the Moth-eye film in practical environments. Three types of films (Moth-eye film, Flat film, and PET film) were used to compare antibacterial effects. Sample films were pasted onto hand-wash sinks at the testing locations. After several hours of elapsed time, bacteria from the surface of sample films were collected using one of three kinds of culture media stampers (to permit identification of bacterial species). The stampers were incubated for 48 hours at 35 °C, and the numbers of colonies were counted.The number of common bacteria including E. coli and S. aureus from the Moth-eye film was significantly lower than that from the PET film (p

The antibacterial effect of a nanostructured film, known as “moth-eye film,” was investigated. The moth-eye film has artificially formed nano-pillars, consisting of hydrophilic resin with urethane acrylate and polyethylene glycol (PEG) derivatives, all over its surface that replicates a moth’s eye. Experiments were performed to compare the moth-eye film with a flat-surfaced film produced from the same materials. The JIS Z2801 film-covering method revealed that the two films produced a decrease in Staphylococcus aureus and Esherichia coli titers of over 5 and 3 logs, respectively. There was no marked difference in the antibacterial effects of the two surfaces. However, the antibacterial effects were reduced by immersion of the films in water. These results indicated that a soluble component(s) of the resin possessed the antibacterial activity, and this component was identified as PEG derivatives by time-of-flight secondary ion mass spectrometry (TOF-SIMS) and Fourier transform infrared spectroscopy (FT-IR). When a small volume of bacterial suspension was dropped on the films as an airborne droplet model, both films showed antibacterial effects, but that of the moth-eye film was more potent. It was considered that the moth-eye structure allowed the bacteria-loaded droplet to spread and allow greater contact between the bacteria and the film surface, resulting in strong adherence of the bacteria to the film and synergistically enhanced bactericidal activity with chemical components. The antibacterial effect of the moth-eye film has been thus confirmed under a bacterial droplet model, and it appears attractive due to its antibacterial ability, which is considered to result not only from its chemical make-up but also from physical adherence.

To develop a compact and low cost excess sludge reduction system, alkaline treatments were carried out using sludge from a petroleum refinery. Alkaline treatment with a concentration of 0.025-0.05 mol/L solubilized about 30% of the sludge after 1 h. Alkaline wastes from petroleum refinery such as sodium sulfide, sodium hydrosulfide, and diisopropanol amine could be used to solubilize about 10-30% of the sludge. Combination of alkaline solubilization (0.05 mol/L NaOH) and high speed mixing achieved about 50% solubilization rate after 1 h at 25°C. Application of this system in a petroleum refinery (600 m3 aeration vessel and 450 m3 sedimentation vessel, 3 m3 solubilization vessel) resulted in average solubilization rate of 44% and reduction rate of sludge of 47% during 64 days operation. Return of alkaline solubilized broth into the aeration vessel did not affect the treatment. In 40 L bench scale experiments, solubilization rate of 59% and sludge reduction rate of 94% were obtained when the amount of sludge solubilization was increased up to 2-3 times of excess sludge produced under the standard activated sludge treatment without the solubilization process.

Background Recent studies report that surfaces displaying micrometer- or nanometer-sized undulating structures exhibit antibacterial effects. In previous work, we described the use of an advanced nanofabrication technique to generate an artificial biomimetic Moth-eye film by coating a polyethylene terephthalate (PET) film with nanoscale moth-eye protrusions made from a hydrophilic resin. This moth-eye film exhibited enhanced antibacterial effects in in vitro experiments. The aim of the present study was to verify the antibacterial efficacy of the Moth-eye film in practical environments. Materials and methods The antibacterial effects of three types of film (Moth-eye film, Flat film, and PET film) were compared. Sample films were pasted onto hand washing basins at the testing locations. After several hours, bacteria were collected from the surface of the sample films with one of three kinds of culture media stamper (to permit identification of bacterial species). The stampers were incubated for 48 hours at 35°C, and the numbers of colonies were counted. Results and discussion The number of common bacteria including E. coli and S. aureus obtained from the Moth-eye film was significantly lower than those from the PET film (p

Reduction of waste materials has become very important in the petroleum industry. Sludge accounts for 51% of waste materials produced in petroleum plants. Most sludge is excess activated sludge discharged by wastewater treatment. We previously developed a new technology to solubilize excess sludge using a combination of alkaline solubilization and high speed mixing. The present study investigated the relationships between sludge solubilization and reduction of final amount of excess sludge based on model experiments with bench scale equipment. Amount of reduced excess sludge was increased with higher amount of solubilized sludge until the amount of solubilized sludge was lower than the excess sludge without solubilization. The amount of reduced excess sludge was approximately equal to the amount of solubilized sludge. COD and T-N concentrations in outlet water and removal rates were not changed with alkaline solubilization. Organic matter in the activated sludge was decreased with higher amount of solubilized sludge due to ash accumulation.

A practical solubilization plant (3 m3) for activated sludge was constructed beside the wastewater treatment plant (600 m3 activated sludge vessel) of a petroleum refinery to solubilize activated sludge with a combination of alkaline treatment and high speed mixer. In the preliminary experiments, optimum alkaline concentration and rotation speed were determined as 0.025 mol/l and 2500 rpm, which gave 40-50% solubilization. Extended operation under these optimum conditions achieved continuous solubilization and return of alkaline solubilized broth into the activated sludge vessel for 64 days. Excess sludge of 144 kg-dry weight/day produced normally in this wastewater plant without solubilization was solubilized and returned by this new plant. The COD of treatment water was 12-27 mg/l and COD removal was 87%. Final average reduction of excess sludge was up to 47% during the 64 days. This new solubilization and sludge reduction plant is stable during extended operation for the reduction of activated sludge without damage to activated sludge.

製油所由来活性汚泥を製油所由来廃棄物を利用して減容化するための基礎知見を得るため，種々の薬剤の汚泥可溶化に及ぼす影響を検討した。廃ソーダや硫化ソーダは水酸化ナトリウムと同等の可溶化力を示した。約10～30分で30～34％の可溶化が達成され，都市下水活性汚泥より急速な可溶化が認められた。アミン類も少ないながら可溶化促進効果を示した。また，温度を上昇させ60℃にすると，廃ソーダや硫化ソーダによる10～30分の処理で45～50％の可溶化が達成された。製油所由来活性汚泥の可溶化が早い理由として，都市下水活性汚泥に比べ微生物相が単純で，細菌相が多いためと推定された。

前報にて，製油所由来活性汚泥を製油所由来アルカリ廃棄物で減容化（可溶化）できることが認められたため，今回，高速撹拌による物理的処理を組み合わせて，可溶化処理の促進効果を検討した。 その結果，市販高速ミキサーを用いて12,000 rpm（線速度15 m/s）で，0.05 mol/l のアルカリ条件で可溶化すると，30分で40％，1時間で50％と，高速撹拌処理を行わない場合に比べ，効果が1.3～1.4倍に増大した。温度を50℃に上昇させると，可溶化促進効果は1時間で55％ にも達し，高速撹拌処理に温度を加えると，可溶化効果はより促進されることを認めた。 さらに，1 m3のベンチスケール可溶化装置を試作し，実験室で得られた最適条件下，実際の廃ソーダを用いた可溶化処理を行ったところ，ほぼ同等の可溶化効果が達成され，簡易な高速撹拌とアルカリ廃棄物の組合せの実用性が確認された。

女性の生理的に起こりうる全身的変化として閉経がある。この生理的なホルモン分泌の減少期が歯周疾患の進行に与える影響を調査する目的で, 閉経前と閉経後の女性歯周疾患罹患患者を被験者として, 臨床パラメーターと歯槽骨吸収量とを比較した。被験者総数は233名 (閉経前群125名, 閉経後群108名) であり, 全身疾患および歯周治療の既往がなく, 咬合性外傷, 若年性歯周炎と診断されたものは除外した。女性歯周病患者各群は閉経前群と閉経後群に, 閉経後群は閉経1～5年群, 閉経6～10年群および閉経11年以上群に分類した。さらに男性歯周病患者106名を対象群とした。被験者は10年ごとの年齢層, 閉経後年数, 歯周疾患進行度により分類した。臨床パラメーターとして現在歯数, プラークコントロールレコード, プロービングによるポケット深さ, Gingival Index, 動揺度, Gingival Bleeding Indexを測定し, さらに歯槽骨吸収量をデンタルX線写真を用いて測定した。歯槽骨吸収量および臨床パラメーターは女性患者の閉経前後群および男性患者群とを比較した。その結果, 閉経前群と比較して閉経後群が歯槽骨吸収量は大きく, 前歯部に閉経後歯槽骨吸収量が大きかった。閉経後群の女性を同年齢層の男性患者群と比較すると, 閉経後問もない50歳代で歯槽骨吸収量が有意に大きくなったことから, 女性の歯周疾患患者における歯槽骨吸収量の増加には閉経というホルモン分泌の激減する全身的変化の影響が考えられた。

Intraoperative acetabular fracture is a rare complication of primary total hip arthroplasty (THA), typically occurring during impaction of the cementless acetabular component. Here we report an unusual case of pelvic discontinuity caused by overreaming of the acetabulum during primary THA. Restoration of posterior columnar continuity was achieved with an autologous fibular graft and a reconstruction plate. Wall defects and cavitary defects were reconstructed with metal mesh and femoral head allograft, followed by placement and fixation of a Kerboull-type acetabular reinforcement device. Previous reports of acetabular fracture during THA have indicated that it has a relatively good prognosis without extensive treatment. However, to our knowledge, there has been no report of pelvic discontinuity necessitating acetabular reconstruction surgery as an intraoperative complication of primary THA.

A 54-year-old woman was admitted to our hospital with the complaint of right upper quadrant pain. Upon physical examination the vital signs of the patient were within normal ranges. Ultrasonography and computed tomography (CT) examination of the abdomen was obtained, which demonstrated a large dilatated cystic structure, measuring approximately 68.6 mm multiply 48.6 mm, with marked distension and inflammation. Additionally, the enhanced CT was characterized by the non-enhanced wall of the gallbladder. As the third examination in this study, magnetic resonance imaging (MRI), namely coronal MRI and magnetic resonance cholangio-pancreatogra (MRCP), were performed. The MRCP demonstrated a dilatation of the gallbladder but detected no neck of the gallbladder. Simple cholecystectomy was performed. Macroscopic findings included a distended and gangrenous gallbladder, and closer examination revealed a counterclockwise torsion of 360 degrees on the gallbladder mesentery. Coronal MRI and MRCP showing characteristic radiography may be useful in making a definitive diagnosis.