Friction Force Mapping of Molecular Ordering and Mesoscopic Phase Transformations in Layered-Crystalline Organic Semiconductor Films.

It is critical to understand molecular ordering processes in small-molecule organic semiconductor (OSC) films in optimizing electronic device applications, although it is difficult to observe and investigate the ordering characteristics at a mesoscopic or device scale. Here, we report that friction force microscopy (FFM) allows visualizing the ordering transformation process from a thermodynamically metastable phase to a stable phase at a mesoscopic scale. We utilized 2-octyl-benzothieno[3,2-b]naphtho[2,3-b]thiophene (2-C8-BTNT) as a typical highly layered-crystalline OSC. We found that the friction force between an AFM tip and spin-coated OSC films significantly depends on whether local film states are in metastable monolayer phase or stable bilayer-type herringbone (b-LHB) phase that exhibits high carrier mobility. The formation of the stable b-LHB phase leads to lower friction than the metastable monolayer phase, clearly visualizing the molecular order. Force map (Fmap) analysis indicates that the lower friction in the b-LHB phase should be associated with the reduction of interfacial adhesion force. Notably, the observed results demonstrate that the spin-coated thin film changes from continuous film with the monolayer phase to rugged microcrystal grains with the b-LHB phase when left at ambient conditions. By contrast, an appropriate post-thermal annealing process facilitates the phase transformation without inducing such morphological changes. The technique provides a unique and effective tool for revealing the relationship between processing conditions and device performance in polycrystalline OSC films.

Comprehensive Application of XFEL Microcrystallography for Challenging Targets in Various Organic Compounds.

There is a growing demand for structure determination from small crystals, and the three-dimensional electron diffraction (3D ED) technique can be employed for this purpose. However, 3D ED has certain limitations related to the crystal thickness and data quality. We here present the application of serial X-ray crystallography (SX) with X-ray free electron lasers (XFELs) to small (a few µm or less) and thin (a few hundred nm or less) crystals of novel compounds dispersed on a substrate. For XFEL exposures, two-dimensional (2D) scanning of the substrate coupled with rotation enables highly efficient data collection. The recorded patterns can be successfully indexed using lattice parameters obtained through 3D ED. This approach is especially effective for challenging targets, including pharmaceuticals and organic materials that form preferentially oriented flat crystals in low-symmetry space groups. Some of these crystals have been difficult to solve or have yielded incomplete solutions using 3D ED. Our extensive analyses confirmed the superior quality of the SX data regardless of crystal orientations. Additionally, 2D scanning with XFEL pulses gives an overall distribution of the samples on the substrate, which can be useful for evaluating the properties of crystal grains and the quality of layered crystals. Therefore, this study demonstrates that XFEL crystallography has become a powerful tool for conducting structure studies of small crystals of organic compounds.

Flip-flop dynamics in smectic liquid-crystal organic semiconductors revealed by molecular dynamics simulations.

Asymmetric liquid-crystal (LC) organic semiconductors, such as 2-decyl-7-(p-tolyl)-[1]benzothieno[3,2-b][1]benzothiophene (pTol-BTBT-C10), exhibit high mobilities exceeding 10 cm2 V-1 s-1. The LC phases play important roles in thermal stability and self-assembly ordering during film deposition and annealing. In this study, we show molecular dynamics simulations of pTol-BTBT-C10 and reveal a unique mechanism of the molecular flip-flop motion at the smectic E/smectic B phase transition.

Control of Polar/Antipolar Layered Organic Semiconductors by the Odd-Even Effect of Alkyl Chain.

Some rodlike organic molecules exhibit exceptionally high layered crystallinity when composed of a link between π-conjugated backbone (head) and alkyl chain (tail). These molecules are aligned side-by-side unidirectionally to form self-organized polar monomolecular layers, providing promising 2D materials and devices. However, their interlayer stacking arrangements have never been tunable, preventing the unidirectional arrangements of molecules in whole crystals. Here, it is demonstrated that polar/antipolar interlayer stacking can be systematically controlled by the alkyl carbon number n, when the molecules are designed to involve effectively weakened head-to-head affinity. They exhibit remarkable odd-even effect in the interlayer stacking: alternating head-to-head and tail-to-tail (antipolar) arrangement in odd-n crystals, and uniform head-to-tail (polar) arrangement in even-n crystals. The films show excellent field-effect transistor characteristics presenting unique polar/antipolar dependence and considerably improved subthreshold swing in the polar films. Additionally, the polar films present enhanced second-order nonlinear optical response along normal to the film plane. These findings are key for creating polarity-controlled optoelectronic materials and devices.

Application and Efficacy of Vitamin E-Bonded Polysulfone Membrane in Acute Blood Purification Therapy.

INTRODUCTION: Acute blood purification therapy (BPT) has been evaluated in the context of intensive care for serious conditions related to systemic inflammation, but its mechanism and efficacy are not fully understood. OBJECTIVE: This study examined the feasibility of using vitamin E-bonded polysulfone membranes (VEPS) for BPT in a LPS-induced rat model of systemic inflammation. METHODS: To evaluate the efficacy of BPT with a VEPS membrane, polysulfone (PS) membranes conventionally used in intensive care were bonded with the antioxidant vitamin E and used in a rat model of lipopolysaccharide (LPS)-induced systemic inflammation. BPT using a PS membrane (PS group) or a VEPS membrane (VEPS group) was performed 6 h after administration of LPS. Extracorporeal circulation was established in normal rats as a control (sham group). Survival rates, histology of lung specimens, and levels of myeloperoxidase (MPO) and high mobility group box-1 (HMGB-1) were examined in each group. RESULTS: Survival rates at 24 h after LPS administration were 100% in the VEPS group and 50% in the PS group. Pulmonary architecture was largely maintained and the level of infiltration of inflammatory cells remained moderate in the VEPS group. Levels of active MPO before and after BPT were significantly higher in the PS and VEPS groups than in the sham group, with no significant differences between the PS and VEPS groups. HMGB-1 levels were significantly elevated after BPT in the PS group. CONCLUSIONS: This study demonstrated that use of the VEPS membrane for BPT increased survival rate and reduced lung injury in a rat model of systemic inflammatory response syndrome (SIRS), suggesting the possible use of VEPS membranes in the treatment of serious conditions related to systemic inflammation.

Insulating Polymer Blend Organic Thin-Film Transistors Based on Bilayer-Type Alkylated Benzothieno[3,2-b]naphtho[2,3-b]thiophene.

Herein, we developed a practical method to produce high-performance organic thin-film transistors (OTFTs) based on highly layered crystalline organic semiconductors (OSCs) that form bilayer-type layered herringbone (b-LHB) packing and exhibit high intrinsic mobility. We applied the insulating polymer blend technique using a typical b-LHB OSC of 2-octyl-benzothieno[3,2-b]naphtho[2,3-b]thiophene (2-C8-BTNT) and fabricated polycrystalline thin-film transistors (TFTs) via short-duration spin coating and subsequent annealing. The use of blends and the choice of polymer additive strongly affected the performance of the polycrystalline TFTs, and poly(methyl methacrylate) (PMMA) blend TFTs exhibited a high mobility exceeding 4 cm2/(V s) and small device-to-device variations. Using extended techniques in atomic force microscopy (AFM), we investigated the thin-film morphologies by bimodal AFM and the carrier transport properties by Kelvin probe force microscopy (KPFM). We demonstrated that the PMMA blend system enables the formation of a well-ordered polycrystalline thin film induced by vertical phase separation between the OSC and PMMA over a large area, resulting in uniform TFT performance. These findings pave the way for obtaining high-performance TFTs using simple processes, representing a substantial advancement toward the realization of printed electronics.

Corrigendum: Protein and Organic-Molecular Crystallography with 300kV Electrons on a Direct Electron Detector.

[This corrects the article DOI: 10.3389/fmolb.2020.612226.].

Pharmacokinetics of indacaterol, glycopyrronium and mometasone furoate administered as an inhaled fixed-dose combination in Japanese and Caucasian healthy subjects.

BACKGROUND: A once-daily (o.d.) fixed-dose combination of indacaterol acetate (IND), glycopyrronium bromide (GLY), and mometasone furoate (MF) delivered via the Breezhaler® device (IND/GLY/MF) is being developed for treatment of asthma. This study compared steady-state pharmacokinetics of IND, GLY and MF between Japanese and Caucasian male subjects after multiple inhalations of IND/GLY/MF o.d. METHODS: This was a single-center, open-label, 2-treatment crossover study with a 21-day washout period. Japanese and Caucasian subjects received IND/GLY/MF 150/50/80 µg (inhaled corticosteroid [ICS] medium-dose) or 150/50/160 µg o.d. (ICS high-dose) for 14 days in each period. Pharmacokinetics were characterized up to 24 h post-dose on Days 1 and 14. RESULTS: In total, 16 Japanese (median age 31 years [range 20-40 years], mean weight 68.3 kg) and 17 Caucasian subjects (median age 27 years [range 21-43 years], mean weight 75.0 kg) were randomized. Geometric mean ratios (Japanese/Caucasian) [90% confidence interval (CI)] for Cmax for IND, GLY and MF at the high ICS dose on Day 14 were 1.31 [1.13, 1.51] 1.38 [1.13, 1.69] and 1.07 [0.969, 1.18], respectively. Geometric mean ratios (Japanese/Caucasian) [90% CI] for AUC0-24h on Day 14 for IND, GLY and MF at the high ICS dose were 1.17 [1.01, 1.35], 1.05 [0.920, 1.20] and 1.15 [1.05, 1.27] respectively. Similar trends were noted for all components for the medium ICS dose treatment. IND/GLY/MF was safe and well tolerated; no AEs suspected to be study drug-related were observed. CONCLUSION: Pharmacokinetics of IND, GLY and MF (high and medium dose) when delivered as a fixed-dose combination were comparable between Japanese and Caucasian subjects. The IND/GLY/MF combination at the administrated doses was safe and well tolerated in both ethnic groups. TRIAL REGISTRATION: Japan Registry of Clinical Trial: jRCT2031200227, retrospectively registered on 04, December, 2020.

In vitro blood compatibility evaluation method: incubating while rotating hemodialyzers filled with fresh human blood.

One of the often-used methods for in vitro evaluation of the blood compatibility of hemodialysis membranes is the circulation of human blood through a miniaturized hemodialyzer. The use of a rather small amount of human blood in its evaluation is one advantage of this method. However, because it is manufactured by a different process than actual ones, a miniaturized hemodialyzer membrane cannot always preserve the properties of actual hemodialyzers. To address this problem, we established a new experimental method that uses a relatively small amount of human blood and actual dialyzers. In this method, a test hemodialyzer and a control hemodialyzer filled with human blood obtained from the same donor is slowly rotated to prevent spontaneous blood cell sedimentation for 4 h at 37 °C. By use of this method, we were able to compare blood compatibility between a polysulfone (PS) membrane and a vitamin E (VE)-bonded PS membrane in terms of their relative antithrombotic, antioxidative, and anti-inflammatory properties. Consistent with many previous reports, the results clearly showed that compared with the PS membrane, VE-bonded PS membrane is more blood compatible. These findings suggest that our method is applicable, at least to in vitro blood compatibility evaluation of PS type dialysis membranes.

Meniscus-controlled printing of single-crystal interfaces showing extremely sharp switching transistor operation.

Meniscus, a curvature of droplet surface around solids, takes critical roles in solution-based thin-film processing. Extension of meniscus shape, and eventual uniform film growth, is strictly limited on highly lyophobic surfaces, although such surface should considerably improve switching characteristics. Here, we demonstrate a technique to control the solution meniscus, allowing to manufacture single-crystalline organic semiconductor (OSC) films on the highest lyophobic amorphous perfluoropolymer, Cytop. We used U-shaped metal film pattern produced on the Cytop surface, to initiate OSC film growth and to keep the meniscus extended on the Cytop surface. The growing edge of the OSC film helped maintain the meniscus extension, leading to a successive film growth. This technique facilitates extremely sharp switching transistors with a subthreshold swing of 63 mV dec-1 owing to the effective elimination of charge traps at the semiconductor/dielectric interface. The technique should expand the capability of print production of functional films and devices.

Regioisomeric control of layered crystallinity in solution-processable organic semiconductors.

The construction and control of 2D layered molecular packing motifs with functionally substituted π-electron cores are crucial for developing organic electronic materials and devices. We investigated a regioisomeric structure-property relationship in high-performance and solution-processable layered organic semiconductors based on mono-octyl-substituted benzothieno[3,2-b]naphtho[2,3-b]thiophene (mono-C8-BTNT). We demonstrated that an isomorphous bilayer-type layered herringbone packing motif is obtainable in a series of four positional isomers of mono-C8-BTNTs whose π-electron core is substituted by an octyl chain at one of the four most peripheral positions with roughly keeping the rod-like molecular shape. These regioisomeric compounds exhibited systematic variations in the solvent solubility and liquid-crystalline phase transitions at elevated temperatures. The analysis of intermolecular interaction energies in the crystals based on dispersion-corrected DFT calculations revealed that the crystals of 2- and 8-mono-C8-BTNTs are more stable than those of 3- and 9-mono-C8-BTNTs owing to the higher ordering of alkyl chain layers in the crystals. Such differences of the stability in their crystal formation are closely correlated with TFT performances, where the single-crystal devices of the 2- and 8-mono-C8-BTNTs substituted at the most peripheral positions exhibit high-performance TFT characteristics with a mobility of approximately 10 cm2 V-1 s-1.

Protein and Organic-Molecular Crystallography With 300kV Electrons on a Direct Electron Detector.

Electron 3D crystallography can reveal the atomic structure from undersized crystals of various samples owing to the strong scattering power of electrons. Here, a direct electron detector DE64 was tested for small and thin crystals of protein and an organic molecule using a JEOL CRYO ARM 300 electron microscope. The microscope is equipped with a cold-field emission gun operated at an accelerating voltage of 300 kV, quad condenser lenses for parallel illumination, an in-column energy filter, and a stable rotational goniometer stage. Rotational diffraction data were collected in an unsupervised manner from crystals of a heme-binding enzyme catalase and a representative organic semiconductor material Ph-BTBT-C10. The structures were determined by molecular replacement for catalase and by the direct method for Ph-BTBT-C10. The analyses demonstrate that the system works well for electron 3D crystallography of these molecules with less damaging, a smaller point spread, and less noise than using the conventional scintillator-coupled camera.

Semiconductive Single Molecular Bilayers Realized Using Geometrical Frustration.

A unique solution-based technology to manufacture self-assembled ultrathin organic-semiconductor layers with ultrauniform single-molecular-bilayer thickness over an area as large as wafer scale is developed. A novel concept is adopted in this technique, based upon the idea of geometrical frustration, which can effectively suppress the interlayer stacking (or multilayer crystallization) while maintaining the assembly of the intralayer, which originates from the strong intermolecular interactions between π-conjugated molecules. For this purpose, a mixed solution of extended π-conjugated frameworks substituted asymmetrically by alkyl chains of variable lengths (i.e., (πCore)-Cn 's) is utilized for the solution process. A simple blade-coating with a solution containing two (πCore)-Cn 's with different alkyl chain lengths is effective to provide single molecular bilayers (SMBs) composed of a pair of polar monomolecular layers, which is analogical to the cell membranes of living organisms. It is demonstrated that the chain-length disorder does not perturb the in-plane crystalline order, but acts effectively as a geometrical frustration to inhibit multilayer crystallization. The uniformity, stability, and size scale are unprecedented, as produced by other conventional self-assembly processes. The obtained SMBs also exhibit efficient 2D carrier transport as organic thin-film transistors. This finding should open a new route to SMB-based ultrathin superflexible electronics.

Vitamin E-Coated Polysulfone Membrane-Based Hemodiafiltration Attenuates Inflammation in a Rat Model of Lipopolysaccharide-Induced Systemic Inflammation.

BACKGROUND: Acute blood purification (ABP) therapy is used regularly in the clinical setting and reportedly alleviates organ failure associated with severe systemic inflammatory responses, leading to reduced mortality. The present study aimed to determine whether there is a difference in efficacy between polysulfone (PS) membranes, which are currently used regularly in the clinical setting, and vitamin E-coated polysulfone (VEPS) membranes, which are anticipated to exhibit the antioxidant and anti-inflammatory properties of vitamin E. METHODS: Male Wistar rats (n=15/group) were intravenously administered 10 mg/kg of lipopolysaccharide (LPS) to establish a systemic inflammatory response model. Six hours after LPS administration, hemodiafiltration (HDF) was performed for 30 minutes using a PS or VEPS membrane under general anesthesia. Blood was collected at various time points, lung tissue was evaluated histologically, and 24-hour survival was assessed. RESULTS: The rats in the VEPS group tended to have a higher survival rate than those in the PS group when undergoing HDF, although the difference was not significant. With respect to lung tissue, the inflammatory response was suppressed to a greater extent in the VEPS group than the PS group. Serum interleukin (IL)-6 levels were reduced at an early stage, plasma antioxidant activity was increased, and oxidative stress was reduced in the VEPS group compared to the PS group. CONCLUSION: Relative to PS membrane-based HDF, the survival rate tended to improve and inflammation was subdued earlier due to the antioxidant activity and early attenuation of inflammation associated with VEPS membrane-based HDF.

TSH and PRL, side-effect markers in aripiprazole treatment: adjunctive aripiprazole-induced thyrotropin oversuppression in a young man with schizophrenia.

A 26-year-old Japanese man was admitted to our unit with exacerbated paranoid schizophrenia. Prior to his admission, daily administration of olanzapine had been sufficient to maintain a partial remission of his schizophrenia, but due to an exacerbation of his delusions, he had then also been prescribed aripiprazole, which had been followed by no improvement in symptoms and a gradual further exacerbation of auditory delusions. Physical examinations, brain MRI and neurophysiological assessment were unremarkable. Blood analysis, however, revealed extremely low thyroid-stimulating hormone (TSH) and prolactin-releasing hormone (PRL) concentration. Interestingly, after aripiprazole discontinuation, he returned to partial remission with an increase in plasma TSH and PRL concentration.

Modified enhanced recovery after surgery (ERAS) protocols for patients with obstructive colorectal cancer.

BACKGROUND: Enhanced recovery after surgery (ERAS) protocols are now well-known to be useful for elective colorectal surgery, as they result in shorter hospital stays without adversely affecting morbidity. However, the efficacy and safety of ERAS protocols for patients with obstructive colorectal cancer have yet to be clarified. METHODS: We evaluated 122 consecutive resections for obstructive colorectal cancer performed between July 2008 and November 2012 at Tokyo Metropolitan Bokutoh Hospital. Patients with rupture or impending rupture and those who received simple colostomy were excluded. The first set of 42 patients was treated based on traditional protocols, and the latter 80 according to modified ERAS protocols. The main endpoints were length of postoperative hospital stay, postoperative short-term morbidity, rate of readmission within 30 days, and mortality. Differences in modified ERAS protocols relative to traditional care include intensive preoperative counseling (by both surgeons and anesthesiologists), perioperative fluid management (avoidance of sodium/fluid overload), shortening of postoperative fasting period and early provision of oral nutrition, intraoperative warm air body heating, enforced postoperative mobilization, stimulation of gut motility, early removal of urinary catheter, and a multidisciplinary team approach to care. RESULTS: Median (interquartile range) postoperative hospital stay was 10 (10-14.25) days in the traditional group, and seven (7-8.75) days in the ERAS group, showing a 3-day reduction in hospital stay (p < 0.01). According to the Clavien-Dindo classification, overall incidences of grade 2 or higher postoperative complications for the traditional and ERAS groups were 15 and 10% (p = 0.48), and 30-day readmission rates were 0 and 1.3% (p = 1.00), respectively. As for mortality, one patient in the traditional group died and none in the ERAS group (p = 0.34). CONCLUSION: Modified ERAS protocols for obstructive colorectal cancer reduced hospital stay without adversely affecting morbidity, indicating that ERAS protocols are feasible for patients with obstructive colorectal cancer.

Sphingosine kinase 1 is upregulated with lysophosphatidic acid receptor 2 in human colorectal cancer.

AIM: To examine the expression of SphK1, an oncogenic kinase that produces sphingosine 1-phosphate (S1P), and its correlation with the expression of LPAR2, a major lysophosphatidic acid (LPA) receptor overexpressed in various cancers, in human colorectal cancer. METHODS: Real-time reverse-transcription polymerase chain reaction was used to measure the mRNA expression of SphK1, LPAR2, and the three major S1P receptors in 27 colorectal cancer samples and corresponding normal tissue samples. We also examined the correlation between the expression of SphK1 and LPAR2. RESULTS: Colorectal cancer tissue in 22 of 27 patients had higher levels of SphK1 mRNA than in normal tissue. In two-thirds of the samples, SphK1 mRNA expression was more than two-fold higher than in normal tissue. Consistent with previous reports, LPAR2 mRNA expression in 20 of 27 colorectal cancer tissue samples was higher compared to normal tissue samples. Expression profiles of all three major S1P receptors, S1PR1, S1PR2, and S1PR3, varied without any trend, with no significant difference in expression between cancer and normal tissues. A highly significant positive correlation was found between SphK1 and LPAR2 expression [Pearson's correlation coefficient (r) = 0.784 and P < 0.01]. The mRNA levels of SphK1 and LPAR2 did not correlate with TNM stage. CONCLUSION: Our findings suggest that S1P and LPA may play important roles in the development of colorectal cancer via the upregulation of SphK1 and LPAR2, both of which could serve as new therapeutic targets in the treatment of colorectal cancer.

Enhanced recovery after surgery (ERAS) protocols for colorectal cancer in Japan.

BACKGROUND: Japan has one of the highest five-year relative survival rates for colorectal cancer in the world, with its own traditions of perioperative care and a unique insurance system. The benefits of enhanced recovery after surgery (ERAS) protocols in the Japanese population have yet to be clarified. METHODS: We evaluated 352 consecutive cases of colorectal cancer resection at Tokyo Metropolitan Bokutoh Hospital between July 2009 and November 2012. Of these, 95 cases were performed according to traditional protocols (traditional group), and 257 according to ERAS protocols (ERAS group), which were introduced to the hospital in July 2010. Primary endpoints included length of postoperative hospital stay, postoperative short-term morbidity, and rate of readmission within 30 days. Intensive pre-admission counselling, no pre- and postoperative fasting (provision of oral nutrition), avoidance of sodium/fluid overload, intraoperative warm-air body heating, enforced postoperative mobilization, and multimodal team care were among the main changes brought about by the introduction of ERAS protocols. RESULTS: The median (interquartile range) length of postoperative hospital stay was 10 (10-12.75) days in the traditional group and seven (6-8) days in the ERAS group, i.e., a three-day reduction (p < 0.05) in the ERAS group. Moreover, the proportion of patients discharged within one week dramatically increased from 1 % to 77 % in the ERAS group. The overall incidence of grade 2 and 3 postoperative complications according to the Clavien-Dindo classification was 9.5 % in the traditional group and 9.3 % in the ERAS group, and 30-day readmission rates were 8.3 % and 6.6 % in the traditional and ERAS groups, respectively. There were no significant differences between the two groups. Although operative time and blood loss did not differ significantly between the two groups, the volume of intraoperative infusion was significantly decreased in the ERAS group (p < 0.05), possibly due to ERAS recommendations to avoid dehydration (i.e., avoidance of sodium/fluid overload, no preoperative fasting). CONCLUSION: ERAS protocols for colorectal surgery helped reduce the length of postoperative hospital stay without adversely affecting morbidity, indicating that ERAS protocols are feasible and effective in Japanese settings as well.

Adsorption properties of an activated carbon for 18 cytokines and HMGB1 from inflammatory model plasma.

The ability of an activated carbon (AC) to adsorb 18 different cytokines with molecular weights ranging from 8 kDa to 70 kDa and high mobility group box-1 (HMGB1) from inflammatory model plasma at 310 K and the mechanisms of adsorption were examined. Porosity analysis using N2 gas adsorption at 77K showed that the AC had micropores with diameters of 1-2 nm and mesopores with diameters of 5-20 nm. All 18 cytokines and HMGB1 were adsorbed on the AC; however, the shapes of the adsorption isotherms changed depending on the molecular weight. The adsorption isotherms for molecules of 8-10 kDa, 10-20 kDa, 20-30 kDa, and higher molecular weights were classified as H-2, L-3, S-3, and S-1 types, respectively. These results suggested that the adsorption mechanism for the cytokines and HMGB1 in the mesopores and on the surface of the AC differed as a function of the molecular weight. On the basis of these results, it can be concluded that AC should be efficient for cytokine adsorption.

Fabrication of alumina films with laminated structures by ac anodization.

Anodization techniques by alternating current (ac) are introduced in this review. By using ac anodization, laminated alumina films are fabricated. Different types of alumina films consisting of 50-200 nm layers were obtained by varying both the ac power supply and the electrolyte. The total film thickness increased with an increase in the total charge transferred. The thickness of the individual layers increased with the ac voltage; however, the anodization time had little effect on the film thickness. The laminated alumina films resembled the nacre structure of shells, and the different morphologies exhibited by bivalves and spiral shells could be replicated by controlling the rate of increase of the applied potentials.