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Objectives Adequate intake of vitamin B complex could be prerequisite to health. However, few studies have been reported on the association of thiamine (vit B1 ), riboflavin (vit B2 ) and niacin (vit B3 ) with periodontal health. This study described the association between periodontal health and dietary vit B1 , vit B2 and vit B3 intake in the Korean population. Methods A total of 12 750 adults aged over 19 years were selected for this study as a sub-sample of the national data set from Korean National Health and Nutrition Examination Survey (IV and V). Periodontitis and gingivitis were defined as Community Periodontal Index (CPI) scores of 3-4 and 1-2, respectively. Information on dietary vit B1 , vit B2 and vit B3 intake was from 24-hour dietary recall method. Multivariable complex logistic regression analyses estimated association between vit B1 , vit B2 and vit B3 intakes and periodontal health after adjusting for various potential confounders. Stratified analyses by age, sex, dyslipidemia and total energy intake were also undertaken. Results The overall estimated prevalence of periodontitis (CPI 3-4) and gingivitis (CPI 1-2) was 29.9% and 46.6%, respectively. Our data showed none of the inadequate intake of vit B1 , vit B2 and B3 showed significant association with gingivitis after adjusting for potential confounders. Inadequate intake of vit B3 showed higher prevalence odds of periodontitis by 1.25 times (adjusted odds ratio = 1.25, 95% CI = 1.07-1.46). The association of vit B3 with periodontitis was stronger in females and participants aged 40-59 years. Conclusions Inadequate dietary intake of vit B3 was associated with periodontitis.

Aim Toothbrushing (TB), dental flossing (DF) and inter-dental brushing (IDB) are regarded as fundamental self-care methods for periodontal health. Few evidences on its effectiveness on periodontal health are available. Hence, this study aimed to evaluate the association of TB, DF, IDB and interaction effect with periodontal health. Materials and methods The nationally representative 4,766 Korean adults aged 19 years and older were cross-sectionally surveyed in 2010 and 2012. Periodontal health was defined as Community Periodontal Index 1-2 for gingivitis and 3-4 for periodontitis. The information about variables was from interview and blood analyses. Multivariable logistic regression analyses and the interaction effect between TB and proximal cleaning (PC: DF and/or IDB) were applied. Results Toothbrushing thrice or more per day and DF were associated with a lower prevalence of periodontitis by both 44%, while the preventive fraction of DF on gingivitis was 30%. The preventive fraction of interaction effects between TB thrice or more and PC were 78% for periodontitis and 68% for gingivitis among 40-59 year age group. Conclusions Toothbrushing and PC are independently associated with periodontal health. Hence, periodontists should recommend TB thrice or more per day and PC such as DF and IDB to promote periodontal health.

Background To study the changes in macular pigment optical density (MPOD) with age in healthy eyes and in patients with dry age-related macular degeneration (AMD) using the Macular Pigment Screener II (MPSII®). Methods One hundred and twenty-six eyes of 126 individuals (51 male, 75 female) were retrospectively evaluated. The MPOD was measured using the MPSII®, which uses a heterochromatic flicker photometry (HFP) method, and the estimated values were reviewed. Spearman’s correlation test was used to evaluate the correlations between the MPOD and age. Simple linear regression analysis was performed to obtain determine the association between the MPOD and age and MPOD. The Kruskal-Wallis test was used to compare the MPOD between among the four groups, and the Mann-Whitney U test was utilized to compare the MPOD between the dry AMD group and the elderly controls Results Estimated MPOD values decreased significantly with increasing age (Spearman’s correlation coefficient, -0.239; p=0.008) in the general population. In the simple regression analysis, a statistically significant linear regression model was observed, and the estimated values of the MPOD decreased by -0.005 as the age increased by one 1 year (p=0.001, Eestimated value of MPOD value = 0.884 – 0.005 ×x Aage). In the healthy population, the estimated MPOD values exhibited a decreasing trend with age, but there were no significant differences according to age, with the exception of patients with dry AMD (p=0.201). The MPOD was significantly lower in patients with dry AMD than in age-matched healthy controls (p=0.001). Conclusions Measurement of the MPOD using the MPSII® is feasible in both healthy individuals and in patients with dry AMD. Early detection of AMD and the contributing risk factors may be possible with regular MPOD screening in elderly patients or in patients with a reduced MPOD.

Oxyfunctionalization of plant oils such as olive oil and soybean oil into C9 carboxylic acids (e.g., n-nonanoic acid and 9-hydroxynonanoic acid) was investigated. The biotransformation was composed of hydrolysis of plant oils by the Thermomyces lanuginosus lipase (TLL) and C9–C10 double-bond cleavage in unsaturated fatty acids by a serial reaction of a fatty acid double bond-hydratase of Stenotrophomonas maltophilia, an alcohol dehydrogenase of Micrococcus luteus, and a Baeyer–Villiger monooxygenase (BVMO) of Pseudomonas putida KT2440 expressed in Escherichia coli. The newly cloned oleate hydratase allowed one to produce 10-hydroxyoctadecanoic acid and 10-hydroxyoctadec-12-enoic acid at a high rate from oleic acid and linoleic acid, respectively, which are major fatty acid constituents of many plant oils. Furthermore, overexpression of a long chain fatty acid transporter FadL in the recombinant E. coli led to a significant increase of whole-cell biotransformation rates of oleic acid and linoleic acid into...

Background:Rheumatoid arthritis is a chronic systemic inflammatory disease known to be associated with many comorbidities. Many women with rheumatoid arthritis (RA) are diagnosed with the disease before completing childbearing, but the risk of comorbidities associated with RA among women in childbearing years is not known.Objectives:We aimed to investigate the risk of comorbidities among Korean women with RA in childbearing years.Methods:From National Health Insurance Service data of 2009-2016, containing inpatient and outpatient claim information for approximately 97% of the Korean population, we identified 20-44 year aged-women with RA and controls without rheumatic diseases such as RA, systemic lupus erythematosus, and ankylosing spondylitis. Prevalence of comorbidities including cancer (Ca), hypertension (HTN), hyperlipidemia (HLD), and diabetes mellitus (DM) were analyzed. The rheumatic diseases and comorbidities were defined by International Classification of Disease (ICD)-10 codes for disease classifications. The comorbidities associated with RA were defined by the ICD-10 codes presented after the RA diagnosis.Results:Total 23,756 women with RA and 208,941 controls were identified. Women with RA had significantly higher prevalence of all comorbidities analyzed compared with the controls (49.92% vs 25.58%, pConclusion:During childbearing years, women with RA are more susceptible to comorbidities leading to a significant burden in this specific population of Korean women in childbearing years.References:[1]Dougados M: Comorbidities in rheumatoid arthritis. Current opinion in rheumatology 2016, 28(3):282-288.[2]Choi IA, Park SH, Cha HS, Park W, Kim HA, Yoo DH, Baek HJ, Lee SG, Lee YJ, Park YB et al: Prevalence of co-morbidities and evaluation of their monitoring in Korean patients with rheumatoid arthritis: comparison with the results of an international, cross-sectional study (COMORA). International journal of rheumatic diseases 2018, 21(7):1414-1422.Table 1.Risk of comorbidities associated with RA among Korean women in childbearing years during 2009-2016RA(n=23,756)Controls(n=208,941)p-valueOR95% CIn(%)n(%)Any comorbidities10,859(45.71)53,423(25.57)2.302.234-2.367 Ca1,235(5.20)8,845(4.23)1.141.072-1.217 DM1,885(7.93)12,606(6.03)1.221.155-1.285 HTN3,274(13.78)17,052(8.16)1.561.495-1.628 HLD8,046(33.87)34,672(16.60)2.442.367-2.516RA, rheumatoid arthritis; Ca, cancer; DM, diabetes mellitus; HTN, hypertension; HLD, hyperlipidemia; OR, odds ratio; CI, confidence intervalDisclosure of Interests:None declared

Background:Gout shows a seasonal variation that widely differs among geographic areas, and we previously reported a seasonal effect on gout in Korea. However, we had no information regarding changes in diet and had only limited laboratory data because this was a retrospective study in patients receiving a urate-lowering therapy. Therefore, we designed this prospective study to elucidate the seasonality and associated factors of gout attacks in Korea.Objectives:To evaluate the seasonality and associated factors of the incidence of gout attacks in Korea.Methods:We prospectively enrolled patients with gout attacks who were treated at nine rheumatology clinics between January 2015 and July 2018 and followed them for 1-year. Demographic data, clinical and laboratory features, and meteorological data including seasonality were collected.Results:Two hundred-five patients (males, 94.1%) were enrolled. The proportion of patients with initial gout attacks was 46.8% (n = 96). The mean age, body mass index, attack duration, and serum uric acid level at enrollment were 50.5 years, 26.1, 10.2 days, and 7.3 mg/dL, respectively. Gout attacks were most common during spring (43.4%,P< 0.001) and in March (23.4 %,P< 0.001). A similar pattern of seasonality was observed in the group with initial gout attacks. Alcohol was the most common provoking factor (39.0%), particularly during summer (50.0%). The mean diurnal temperature change on the day of the attack was highest in the spring (10.3°C), followed by winter (9.1°C), summer (8.1°C), and fall (8.0°C) (P= 0.027). The mean change in humidity between the 2 consecutive days (the day before and the day of the attack) was significantly different among the seasons (3.4%, spring; 0.2%, summer; 0.4%, fall; -3.9%, winter;P= 0.015). One hundred twenty-five (61%) patients completed 1-year follow-up (51% in the initial attack group). During the follow-up period, 51 gout flares developed (18 in the initial attack group). No significant seasonal variation in the follow-up flares was found.Conclusion:In this prospective study, the most common season and month of gout attacks in Korea were spring and March, respectively. Alcohol was the most common provoking factor, particularly during summer. Diurnal temperature changes on the day of the attack and humidity changes from the day before the attack to the day of the attack were associated with gout attack in our cohort.References:[1]Choi HJ, Lee CH, Lee JH et al. Seasonality of gout in Korea: a multicenter study. J Korean Med Sci 2015;30:240-4.Disclosure of Interests: :None declared

Whole-cell biotransformation of fatty acids can be influenced by the activities of catalytic enzymes and by the efficiency of substrate transport into host cells. Here, we improved fatty acid hydration activity of the recombinant Escherichia coli expressing an oleate hydratase of Stenotrophomonas maltophilia by targeting the catalytic enzyme into the periplasm instead of the cytoplasm. Recombinant E. coli producing OhyA in the periplasm under guidance of the PelB signal sequence (E. coli OhyA_PP) exhibited significantly greater hydration activity with oleic acid and linoleic acid compared to a recombinant E. coli producing OhyA in the cytoplasm (E. coli OhyA_CS). For example, the oleate double bond hydration rate of E. coli OhyA_PP was >400 μmol/g dry cells/min (400 U/g dry cells), which is >10-fold higher than that of E. coli OhyA_CS. As the specific activities of the enzymes targeted into the cytoplasm and periplasm were comparable, we assumed that targeting OhyA into the periplasm could accelerate fatty acid transport to the catalytic enzymes by skipping the major mass transport barrier of the cytoplasmic membrane. Our results will contribute to the development of whole-cell biocatalysts for fatty acid biotransformation.

Hydroxy fatty acids are used as starting materials for the production of secondary metabolites and signalling molecules as well as in the manufacture of industrial fine chemicals. However, these compounds are usually difficult to produce from renewable biomass by chemical means. In this study, linoleate double bond hydratases of Lactobacillus acidophilus NBRC 13951 were cloned for the first time. These enzymes were highly specific for the hydration of the C-9 or the C-12 double bond of unsaturated fatty acids (e.g., linoleic acid). Thereby, the enzymes allowed the selective production of hydroxy fatty acids such as 13-hydroxy-cis-9-octadecenoic acid and 10-hydroxy-cis-12-octadecenoic acid from linoleic acid. In addition, the hydroxy fatty acids were further converted into industrially relevant carboxylic acids (e.g., 12-hydroxy-cis-9-dodecenoic acid, α,ω-tridec-9-enedioic acid) and lactones (i.e., δ-decalactone, γ-dodecelactone) via whole-cell biocatalysis using an enzyme cascade. This study thus contributes to the preparation of hydroxy fatty acids, unsaturated carboxylic acids, and lactones from renewable unsaturated fatty acids.

Oils and fatty acids are important renewable resources provided by nature. Therefore, biotransformation of renewable oils and fatty acids into industrially relevant C9 chemicals was investigated in this study. Olive oil, soybean oil, yeast derived oil, and microalgae fatty acid methyl esters were converted into n-nonanoic acid, 9-hydroxynonanoic acid, and 1,9-nonanedioic acid by a lipase and a recombinant Escherichia coli expressing oleate hydratase, long chain secondary alcohol dehydrogenase, Baeyer-Villiger monooxygenase, long chain primary alcohol dehydrogenase, and aldehyde dehydrogenase. It was found that n-nonanoic acid and azelaic acid could be produced to a concentration of 4.3 mM from 3 g/L olive oil with a specific product formation rate of 3.1 U/g dry cells. Biotransformation rates were influenced by compositions of fatty acids and purity of the starting material. This study may contribute to the production of industrially relevant C9 chemicals from renewable oils and fatty acids by simultaneous enzyme/whole-cell biotransformation.

Backgrounds The association of dietary vitamin C (vit C) on periodontitis requires more valid evidence from large representative samples to enable sufficient adjustments. This study aimed to evaluate the association between dietary vit C intake and periodontitis after controlling for various confounders in the representative Korean adult population Method A total of 10,930 Korean adults (≥19 years) from the fourth Korean National Health and Nutrition Examination Survey data set were included in this cross-sectional study. Periodontitis was defined as community periodontal index score of 3 or 4. Dietary vit C intake was estimated from a 24-hour dietary record, and categorized into adequate and inadequate according to the Korean Estimated Average Requirement value. Potential confounders included age, sex, income, frequency of tooth brushing, use of floss, dental visit, drinking, smoking, diabetes, hypercholesterolemia, hypertension, and obesity. A multivariable logistic regression analysis and stratified analysis were applied. Results Those with inadequate dietary vit C intake were more likely by 1.16 times to have periodontitis than those with adequate dietary vit C intake (adjusted odds ratio [aOR] = 1.16, 95% confidence interval = 1.04–1.29). Lowest and middle-low quartile of dietary vit C intake, compared to highest quartile of dietary vit C intake, showed significant association (aOR = 1.28 and 1.22 respectively), which was in a biological-gradient relationship (trend-p

Biotransformation of long-chain fatty acids into medium-chain α,ω-dicarboxylic acids or ω-aminocarboxylic acids could be achieved with biocatalysts. This study presents the production of α,ω-dicarboxylic acids (e.g., C9, C11, C12, C13) and ω-aminocarboxylic acids (e.g., C11, C12, C13) directly from fatty acids (e.g., oleic acid, ricinoleic acid, lesquerolic acid) using recombinant Escherichia coli-based biocatalysts. ω-Hydroxycarboxylic acids, which were produced from oxidative cleavage of fatty acids via enzymatic reactions involving a fatty acid double bond hydratase, an alcohol dehydrogenase, a Baeyer–Villiger monooxygenase and an esterase, were then oxidized to α,ω-dicarboxylic acids by alcohol dehydrogenase (ADH, AlkJ) from Pseudomonas putida GPo1 or converted into ω-aminocarboxylic acids by a serial combination of ADH from P. putida GPo1 and an ω-transaminase of Silicibacter pomeroyi. The double bonds present in the fatty acids such as ricinoleic acid and lesquerolic acid were reduced by E. coli-native enzymes during the biotransformations. This study demonstrates that the industrially relevant building blocks (C9 to C13 saturated α,ω-dicarboxylic acids and ω-aminocarboxylic acids) can be produced from renewable fatty acids using biocatalysis.

The generation of staurolite from the mixed-phase muscovite and the metamorphic environment of shales in the Baekunsa formation, Hongsan, Buyeo, were studied using electron probe micro analysis (EPMA). The average chemical composition of mica-type mineral is , and shows a characteristics of the so-called illite with a low content of interlayer cations and Fe, Mg in octahedral sites. The mica-type mineral shows a typical chemical composition of the mixed-phase among muscovite, pyrophyllite, and chlorite (mixed-phase muscovite, ). The staurolite, in general, occurs with the mixed-phase muscovites, pyrophyllites, and aluminosilicates in the rock. We consider that staurolite can be formed by a reaction involving pyrophyllite such as pyrophyllite+chloritoid. The chloritoid is formed by a reaction between pyrophyllite and chlorite and is supposed to be used up in the process of staurolite formation. As a result, the mixed-phase muscovite, formed during the transition of illite to muscovite, plays an important role for the generation of the staurolite. Considering that the reaction occurs at the temperature higher than and pyrophyllites transform into aluminosilicates at , the shale in the Baekunsa formation can be considered to have been experienced a metamorphic temperature between .

Microbial hydroxylation of long chain fatty acids has been extensively investigated. However, biotransformation productivity remains below ca. 1.0 g/g cell dry weight (CDW)/h under process conditions. In the present study, a highly efficient microbial hydroxylation process to convert oleic acid into 10-hydroxystearic acid was developed. A recombinant Escherichia coli expressing ohyA, the gene encoding oleate hydratase of Stenotrophomonas maltophilia, was used as the biocatalyst. Investigation of the ohyA expression and biotransformation conditions (e.g., inducer concentration, gene expression period before initiating biotransformation, mixing condition of reaction medium) enabled 10-hydroxystearic acid to accumulate to a final concentration of approximately 46 g/L in the culture medium. The specific product formation rate and product yield reached approximately 2.0 g/g CDW/h (i.e., 110 U/g CDW) and 91%, respectively. The specific product formation rate was more than 3-fold higher than those of a bioprocess using wild type Stenotrophomonas sp. cells. Additionally, the product of the whole-cell biotransformation was recovered at a yield of 70.9% and a purity of 99.7% via solvent fraction crystallization at low temperature. These results will contribute to developing a biological process for hydroxylation of oleic acid.

세피올라이트는 결정구조와 화학조성이 팔리고스카이트(Palygorskite)와 유사한 점토광물로서, 층상구조와 쇄상구조가 혼합된 리본구조의 결정구조를 갖는 광물이며(Newman and Brown, 1987), 전 세계 매장량의 70% 정도가 스페인에 분포하고 있다(박성완과 이상현, 2006). 다양하고 유용한 특성을 가진 세피올라이트는 많은 분야에서 사용되고 있는데(Jones and Galan, 1988), 특히 뛰어난 흡습력과 악취를 발생시키는 박테리아의 번식을 지연시키는 성질을 가지고 있어서 흡습제와 방취제 등의 용도로 널리 사용되고 있다(Singer and Galan, 1984). 우리나라에서는 경북 상주지역과 울산의 사문석 광산에서 세피올라이트가 발견된 이후(Shimo-saka and Kawano, 1969; 황진연, 1991), 새롭게 발견된 세피올라이트에 대한 보고와 이들에 대한 광물학적 연구가 거의 이루어지지 않았다. 전북 장수군 장계면 일대는 선캠브리아기의 흑운모 편마암과 변성퇴적암류가 분포하는 지역으로(그림 1), 과거 변성퇴적암류에 포함된 백운암질석회암을 채굴하는 광산들이 있었던 지역이다(홍승호와 윤욱, 1993). 이들 석회암 광산 중 금곡광산은 현재 제일산업에서 돌로마이트를 채굴․생산하고 있는데, 채굴 중 세맥으로 존재하는 미지의 광물시

Mica-type phyllosilicate particles in the shales of the Manhang formation at the Taeback area in the Kangwon Province were studied using electron probe microanalysis (EPMA) and transmission electron microscopy (TEM). The average chemical formula of the mica-type phyllosilicate mineral analysed by EPMA is K1.35(Fe0.18Mg0.03Al3.86)(Si6.55Al1.45)O20(OH)4. Low K contents compared to the ideal chemistry of muscovite indicate the presence of illite in the mica-type phyllosilicate particle. X-ray diffraction study showed that pyrophyllite commonly coexists with muscovite in the shales from the Manhang Formation. TEM observations showed both the interlayer and intralayer mixing of 9.3-Å pyrophyllite and 10-Å muscovite layers. The low K content of the mica-type phyllosilicates apparently

Structural and compositional properties of ferritin cores were studied by transmission electron microscopy (TEM) and inductively coupled plasma (ICP) spectrometry. The native tadpole ferritin (TdF) contains 880 Fe atoms per molecule of protein and considerable amounts of phosphate (Fe:Pi=5.2). The core size of TdF is 6.75 (±0.72) nm. In the ferritin reconstituted with 1170 Fe atoms per molecule of protein, the core size is 8.31 (±0.97) nm. Electron diffraction patterns of both native and reconstituted tadpole ferritins show poor crystallinity, giving diffuse diffraction lines. Both ferritin cores were identified as ferrihydrite. Reconstituted iron cores of recombinant tadpole H-chain ferritin produced in Escherichia coli contain 1280 Fe atoms and show similar crystallinity with the size of 8.08 (±0.90) nm.

A highly robust gap-fill process technology of spin-on glass (SOG) was developed for the interlayer dielectric (ILD) in sub-30nm devices. We revealed that the filling behavior of SOG within gaps during spin-coating is mainly dependent on the capillary effect. The highly wettable surface treatment prior to SOG coating was found to enhance the gap-fill performance remarkably. This technique plays a key role in maximizing capillary effect by raising surface wettability. The filling capability was also improved by optimization of baking temperature to minimize the viscosity of SOG. It was finally found that the defects of contact bridges due to poor filling of SOG were reduced to be almost free by those unique process refinements.

Incorporation of metal nanoparticles in Polyaniline composites could effectively improve its optical, thermal and electrical properties and making it an ideal for the use in semiconductor industry. In this study Ag nanoparticles were uniformly dispersed ultrasonically in the solution of polyaniline emeraldine base (PANIEB) and isopropyl alcohol. PANIEB used in this experiment were doped with polymer of methacrylic acid ester and vinyl verstate. The results about the morphological, optical and electrical properties of Ag-PANIEB with IPA colloid as a function of different concentration of Ag nanoparticles (Such as 25%, 50%, 100% by weight) were presented and discussed.

Treatment ofsmectite with laurylamine hydrochloride was verified to cause expansion of d(001) which may be retained and observed in ion-milled samples by transmission electron microscopy. The spacings between layers as observed in lattice fringe images, however, are variable and may be as small as 10 A. The method therefore produces ambiguities in differentiating between some smectites and illites, similar to those that have been found for untreated samples; e.g., on this basis, expanded layers may be inferred to be smectite, but layers with d-values approaching 10  may be either illite or smectite. Expansion also destroys the original rock texture, which, therefore, must be observed using only untreated samples.

Diffusion of K during analytical electron microscopy (AEM) results in anomalously low count rates for this element. As the analysis area and specimen thickness decrease, count rates become dispro- portionally lower. Adularia and muscovite show different diffusion profiles during AEM; for muscovite a strong dependence of diffusion on crystallographic orientation has been observed. Conditions giving rise to reliable chemical data by AEM are the use of a wide scanning area (>800 x 800 A) and/or large beam size to reduce the effect of diffusion of alkali elements, a specimen thickness greater than about 1000 ~, constant instrument operating conditions, and the use of a homogeneous, well-characterized standard sample. The optimum thickness range was obtained by determining the element intensity ratio vs. thickness curve for given operating conditions. The standard and unknown should have a similar crystal structure and, especially for strongly anisotropic minerals such as phyllosilicates, a similar crys- tallographic orientation with respect to the electron beam.

Phyllosilicates in rocks which are transitional from mudstone to slate from Lehigh Gap, Pa., have been studied by a variety of techniques, including high resolution Transmission Electron Microscopy and Analytical Electron Microscopy. The principal minerals are “white mica” which is transitional from illite in mudstone to ordered twolayer mica in slate, and chlorite. 7A berthierine occurs more rarely. Dioctahedral and trioctahedral layers are shown to be interleaved in individual crystals at all scales between the following two end members: (1) both random and regular 1∶1 interlayering at the scale of individual layers, as shown, in part, by lattice fringe images. (2) packets of trioctahedral and dioctahedral layers up to a few thousand Angstroms or microns in thickness, detectable with ordinary optical techniques. The complete range of intermediate structures is represented in samples which are in transition to slate. Bulk analytical (EMPA), X-ray diffraction or other measurements are shown to result in averages over both kinds of layers when TEM techniques are not used.

Data primarily for phyllosilicates have been obtained for the continuous transitional sequence from mudstone to slate with well-developed slaty cleavage at Lehigh Gap, Pennsylvania, and for slates from quarries in the same area. Samples were studied by optical microscopy, powder X-ray diffraction and electron microprobe analysis, with emphasis on transmission and analytical electron microscopy. Mineral grains are virtually free of deformation-induced strain. Concomitant with the gradual development of cleavage normal to bedding the following changes are observed or confirmed: (1) the orientation of phyllosilicate grains changes discontinuously from being preferentially parallel to bedding to being parallel to cleavage; (2) crystal imperfections as expressed in layer terminations, low angle grain boundary-like features and other defects decrease in density; (3) complex mixed layering is replaced by homogeneous packets of layers of single phases and (4) illite transforms to muscovite, with increase in K + A1 and change from a lMd to 2M polytype. Slaty cleavage apparently develops due in part to pressure solution of phyllosilicates oriented parallel to bedding, mass transport of components, and crystallization to form new grains parallel to cleavage. It reflects transitions from imperfect, metastable phases toward ordered stable phases in a low temperature (-225°C) metamorphic environment.

Phyllosilicates in samples from Gulf Coast cores and the Martinsburg Formation near Lehigh Gap, Pennsylvania (which together represent a continuous sequence from mudstone to slate) are shown by TEM studies to possess imperfections on a massive scale and to exhibit a progressive increase in perfection through diagenesis and low-grade metamorphism. In shallow portions (1,750 and 2,450 m) of the Gulf Coast core, smectites have irregular and curved layers with high dislocation densities and many small-angle, grainlike boundaries. In both the deeper portion (5,500 m) of the Gulf Coast sediments and in the Martinsburg mudstone samples, gram perfection increases in illites, but a complex mosaic structure with small-angle grain boundaries and edge dislocations still prevails. In the Martinsbu g slate, phyllosilicates exhibit layers which are continuous and straight and have few imperfections. Original clays which form at low temperatures have highly imperfect and metastable structures. Changes with increasing diagenesis are akin to annealing processes, with increasing perfection of grains being an approach to a more stable, strain-free structure. Temperature, pore water, time, and other variables affecting these changes act only to promote reaction rates to the defect-free, stable structures.

Phyllosilicates that occur in shales and slates show complex features as generally detected by methods such as X-ray diffraction. Diffraction patterns commonly display features such as broadened and asymmetric peaks which in many cases have been shown to reflect random interlayering of more than one kind of phyllosilicate1; for example, illite–smectite and vermiculite–chlorite. Ordered interlayering of more than one phase has also been frequently observed. However, powder diffraction data generally provide insight only into the differences between units of many layers and then they only yield average values. The possibility of variations within individual layers can be investigated using transmission electron microscopy (TEM) and analytical electron microscopy (AEM). We report here on the occurrence of transitions within individual phyllosilicate layers from one trioctahedral structure to another (ferroan lizardite to chlorite) and from trioctahedral to dioctahedral (illite) layers. These variations in structure introduce a new range of complexities into those non-equilibrium phyllosilicate structures which occur in low-temperature sedimentary environments.