Ultrastructural changes in the melanocytes of aging human choroid

Retinal pigment epithelial cells as well as choroidal melanocytes (CM) possess melanin granules. The former show clear, age-related changes (formation of lipofuscin granules with a concomitant decrease in melanin content); however, data on changes in the CM with aging are fairly limited. We examined CM in human macular and mid-peripheral areas by light- and transmission electron microscopy in 50–94 year-old donor eyes (N = 12). Unlike in the choroid of lower ages, the melanocytes from aging choroid (>75 years) showed partial fusion of about 8–15 melanosomes, forming rosettes-like structures. Besides, there was evidence of emptiness in cytoplasm caused by the loss of melanosomes in aged CM, as was confirmed by quantification in macular part of choroid. In advanced aged eyes (85–94-year-old), the CM possessed many lipid droplets as well as irregular lipofuscin granules, the latter had a tendency to fuse with melanosomes, as happens in aged retinal pigment epithelium. Macrophages in their cytoplasm contained abundant irregular as well as clumped melanosomes of variable size, suggesting that damaged granules/melanocytes are cleared by these phagocytes. These obvious changes in the CM are likely to make the choroid prone to damage by visible light.     

Analysis of the penetration of a caffeine containing shampoo into the hair follicles by in vivo laser scanning microscopy

In previous in vitro investigations, it was demonstrated that caffeine is able to stimulate the hair growth. Therefore, a penetration of caffeine into the hair follicle is necessary. In the present study, in vivo laser scanning microscopy (LSM) was used to investigate the penetration and storage of a caffeine containing shampoo into the hair follicles. It was shown that a 2-min contact time of the shampoo with the skin was enough to accumulate significant parts of the shampoo in the hair follicles. A penetration of the shampoo up to a depth of approx. 200 μm could be detected, which represents the detection limit of the LSM. At this depth, the close network of the blood capillaries surrounding the hair follicles commences. Even after 24 h, the substance was still detectable in the hair follicles. This demonstrates the long-term reservoir function of the hair follicles for topically applied substances such as caffeine.     

Features of neodymium laser epilation

The efficiency and features of the use of the Nd:YAG laser for epilation in comparison with ruby, alexandrite, diode lasers and a broadband light source were studied. Procedures for calculating the temperature distribution of the hair follicle over the entire depth of its position in the skin and temperatures of undesirable heating of surrounding skin regions under exposure to Nd:YAG laser radiation were developed. The heating temperature of hair follicles with black, brown, and light hair was calculated. The heating temperature of follicles of biological tissues for patients with light, swarthy, and dark skin was calculated. The ranges of the neodymium laser applicability to hair and skin colors during epilation procedures were determined. The ways of optimization of the output radiation parameters (pulse energy and duration, light spot sizes) for removing variously colored hair of patients with various skin phototypes were directed. The ways of epilation technology improvement (active skin cooling, injection of special dyes into hair follicles, and others) were proposed.     

叶片茸毛对叶片反射光谱及高光谱植被指数的影响研究

很多高光谱植被指数被用于对植被的生化物质含量进行非破坏性的估计与反演。由于这些指数都是利用不同波段的反射率计算而得到的,因而对叶片反射具有很大影响的茸毛等叶表结构对这些植被指数的反演精度的影响不容忽视。本研究发现去茸毛处理使得在400～1 000nm范围的的光谱反射都有所下降,但在各个波段的变化并不均匀。通过对比39个现有的高光谱植被指数在经过去茸毛处理前后的变化,发现一些只单独利用可见光或者近红外波段的高光谱植被指数,如CTR1:R695/R420,D740/D720,WBI:R900/R970,R860/(R550×R708)以及红边指数(REP)比大多数既使用可见光又使用近红外波段的高光谱植被指数受茸毛变化影响小,它们对茸毛的低敏感性可以使其在进行植被生化物质反演时更具有普适性。     

Transdermal water mobility in the presence of electrical fields using MR microscopy.

Magnetic resonance microscopy of skin from hairless rats under the influence of electrical fields was conducted for two cases: 1) low voltage constant electrical fields and 2) high-voltage short pulse, electrical fields. Under conditions of the low voltage and low current iontophoresis, i.e., 0 to 20 V, and 0 to 0.5 mA/cm2, it was found that the skin structure, as observed by magnetic resonance microscopy, did not significantly change until 20 Volts were applied across the 0.1 cm thick skin. Under these conditions, the viable epidermis appeared to swell, and this result corresponded to observations from scanning electron microscopy and other research from the literature. High voltage electrical fields, i.e., 220 V 1 ms pulses repeated once per second, appeared to hydrate the stratum corneum as is consistent with published literature on electroporation. In the case of iontophoresis, water self-diffusion coefficients in the epidermis and hair follicle regions at all voltages were affected by the electrical field. Statistical analysis at the 95% confidence level for the comparison of the average differences between diffusion coefficients with the electrical field on and with the electrical field off for pair matched pixels for the viable epidermis show that for 5 V (p = 0.00377), 10 V (p = 0.0108), 20 V (p = 0.0219) regimes there are statistically significant (p < or = 0.05) changes due to the applied electric field. The same analysis for the hair follicle region at 5 V (p = 6.89 x 10(-7)), 10 V (p = 1.42 x 10(-5)), 20 V (p = 3.23 x 10(-3)) also show statistically significant changes (p < or = 0.05). When the electroporation pulse was applied, the water diffusion coefficients increased by about 30% to 6.6 x 10(-6) cm2/s +/- 2.4 x 10(-7) cm2/s and 8.3 x 10(-6) cm2/s +/- 3.7 x 10(-7) cm2/s, for the epidermis and hair follicle regions, respectively. Significant differences were noted between diffusion coefficients in the viable epidermis and the hair follicles for all cases.     

Jet fuel toxicity: skin damage measured by 900-MHz MRI skin microscopy and visualization by 3D MR image processing

The toxicity of jet fuels was measured using noninvasive magnetic resonance microimaging (MRM) at 900-MHz magnetic field. The hypothesis was that MRM can visualize and measure the epidermis exfoliation and hair follicle size of rat skin tissue due to toxic skin irritation after skin exposure to jet fuels. High-resolution 900-MHz MRM was used to measure the change in size of hair follicle, epidermis thickening and dermis in the skin after jet fuel exposure. A number of imaging techniques utilized included magnetization transfer contrast (MTC), spin-lattice relaxation constant (T1-weighting), combination of T2-weighting with magnetic field inhomogeneity (T2*-weighting), magnetization transfer weighting, diffusion tensor weighting and chemical shift weighting. These techniques were used to obtain 2D slices and 3D multislice–multiecho images with high-contrast resolution and high magnetic resonance signal with better skin details. The segmented color-coded feature spaces after image processing of the epidermis and hair follicle structures were used to compare the toxic exposure to tetradecane, dodecane, hexadecane and JP-8 jet fuels. Jet fuel exposure caused skin damage (erythema) at high temperature in addition to chemical intoxication. Erythema scores of the skin were distinct for jet fuels. The multicontrast enhancement at optimized TE and TR parameters generated high MRM signal of different skin structures. The multiple contrast approach made visible details of skin structures by combining specific information achieved from each of the microimaging techniques. At short echo time, MRM images and digitized histological sections confirmed exfoliated epidermis, dermis thickening and hair follicle atrophy after exposure to jet fuels. MRM data showed correlation with the histopathology data for epidermis thickness (R²=0.9052, P<.0002) and hair root area (R²=0.88, P<.0002). The toxicity of jet fuels on skin structures was in the order of tetradecane>hexadecane>dodecane. The method showed a sensitivity of 87.5% and a specificity of 75%. By MR image processing, different color-coded skin structures were extracted and 3D shapes of the epidermis and hair follicle size were compared. In conclusion, high-resolution MRM measured the change in skin epidermis and hair follicle size due to toxicity of jet fuels. MRM offers a three-dimensional spatial visualization of the change in skin structures as a method of toxicity evaluation and for comparison of jet fuels.     

Uptake of 3H-cAMP by retinal pigment epithelium isolated from bluegill sunfish (Lepomis macrochirus)

Background  

In bluegill sunfish, the melanin-containing pigment granules of the retinal pigment epithelium undergo cyclic movements in response both to ambient lighting and circadian cues. Pigment granules aggregate into the cell body at night (in the dark), and disperse into apical processes during the day (in the light). Regulation of pigment granule aggregation in a number of fishes depends on modulating the intracellular levels of cyclic adenosine monophosphate.     

Investigation of differences in follicular penetration of particle-and nonparticle-containing emulsions by laser scanning microscopy

Hair follicles represent a long-term storage of topically applied drugs and cosmetics in the skin. Analyzing the penetration of particle-and nonparticle-containing formulations by laser scanning microscopy, it was found, surprisingly, that particles at a size similar to the thickness of the keratin cells of the hair penetrate more efficiently into the hair follicles. These results were obtained from in vitro and in vivo investigations. It seems that the moving hairs in the follicles act as a geared pump because of the zigzag structure of the surface of the hairs. This pumping effect probably pushes particles with the corresponding size deep into the hair follicles.     

Artificial neural networks applied to the classification of hair samples according to pigment and sex using non-invasive analytical techniques

In this study, we investigated the possibility of using an artificial neural network (ANN) to classify human hair samples according to pigment (original or bleached hair) and sex (female or male) from numerical data obtained by wavelength dispersive X-ray fluorescence (WDXRF) and by laser-induced breakdown spectroscopy (LIBS). The results were promising, showing that the developed ANNs are able to classify the pigment and donor sex of hair samples with 100% and 89.5% accuracy, respectively, in the test set using WDXRF data. For the LIBS data in the test set, 100% of the pigment classifications were correct, and 78.9% of the donor sex classifications were correct.     

8～14μm波长低红外发射率涂料的研究

研究了红外隐身涂料粘合剂的物理和化学性能,以及红外隐身涂料粘合剂、填料、颜料颗粒的红外发射率。通过研究发现,铝粉和氧化铅具有较低的发射率,并得到了以有机硅清漆和EPDM(三元乙丙橡胶)接枝聚合物为基体的低红外发射率涂料,它有助于对红外隐身涂料粘合剂、填料、颜料颗粒的选择。     

Intraovarian control of selective follicular growth and induction of oocyte maturation in mammals

In newborn mammals, most of the germ cell population rests in a pool of quiescent small follicles in the ovaries. Regularly throughout adulthood, a small percentage of these oocytes and follicles grows to a certain stage of development and then either degenerates or matures and ovulates. This entire process is under both exogenous and endogenous control. Recent work, including my laboratory’s, has clarified that cytokines and glycosaminoglycans are involved as exogenous and endogenous factors in ovarian follicular development, atresia, and maturation in mammals. The present article describes our contribution regarding the cytokines and ovarian glycosaminoglycans that act as intraovarian regulators of follicular development and oogenesis, including oocyte maturation, in mammals.     

The comparison of laser surface designing and pigment printing methods for the product quality

Developing new designs by using the computer and transferring the designs that are obtained to textile surfaces will not only increase and facilitate the production in a more practical manner, but also help you create identical designs. This means serial manufacturing of the products at standard quality and increasing their added values. Moreover, creating textile designs using the laser will also contribute to the value of the product as far as the consumer is concerned because it will not cause any wearing off and deformation in the texture of the fabric unlike the other methods.In the system that has been designed, the laser beam at selected wavelength and intensity was directed onto a selected textile surface and a computer-controlled laser beam source was used to change the colour substances on the textile surface.Pigment printing is also used for designing in textile and apparel sector. In this method, designs are transferred to the fabric manually by using dyestuff.In this study, the denim fabric used for the surfacing trial was 100% cotton, with a weft count per centimeter of 20 and a warp count per centimeter of 27, with fabric weight of 458 g/m².The first step was to prepare 40 pieces of denim samples, half of which were prepared manually pigment printing and the other half by using the laser beam. After this, some test applications were done. The tensile strength, tensile extension and some fastness values of designed pieces with two methods were compared according to the international standards.     

Active transport in complex media: Relationship between persistence and superdiffusion

We study the relationship between anomalous diffusion and persistent motion of micron-sized particles moving in a viscoelastic environment and subjected to an external noise. In the framework of a generalized Langevin equation, we compare the analytical expressions of the mean square displacement and the mean cosine of the turning angle. Both magnitudes can be easily computed from the particles trajectories, and allow us to investigate the different anomalous regimes typically obtained, for instance, in single particle tracking experiments within living cells. Finally, we analyze the directional changes occurring during the motion of pigment organelles driven by molecular motors in Xenopus laevis melanocytes, as an example of application of our model.     

基于色彩参数和高光谱特征的针叶树种色素含量预估

光谱成像技术广泛应用于植物理化参数无损伤测定等领域研究,而色素与色彩参数相关性研究也有学者探索.但比较并优选分别以色彩参数值、光谱参数值作为自变量与色素含量拟合出的模型,还未见报道.本实验以5种针叶树种为研究对象,筛选蓝边幅值Db、黄边幅值Dy、红边幅值Dr、绿峰幅值Rg、红谷幅值Rr、蓝边面积SDb、黄边面积SDy、...     

可见光谱法无损识别壁画文物矿物质颜料的研究

针对取样分析技术破坏壁画文物完整性问题,提出非接触式可见光谱法原位无损识别壁画文物矿物质颜料物质成分和粒径的方法。构建非接触式获取平台原位无损采集壁画文物表面可见光谱;通过调研和实测数据分析,制备了壁画矿物质颜料可见光谱数据库。分析数据库中的光谱数据发现：同种化学成分的颜料具有相同的吸收特性,表现为光谱曲线峰值位置和几何轮廓的相似性;在不同粒径下又呈现出不同的散射特性,表现为光谱曲线幅度的差异性。为此,构建了壁画文物矿物质颜料物质成分和粒径的可见光谱法无损识别流程和识别方法,即提取光谱曲线几何轮廓特征构建表征空间实现了颜料物质成分的识别;在此基础上,提出了矿物质颜料需进行物理特征识别的理念,并建立了光谱曲线幅度积分值与颜料平均粒径间的拟合关系,实现颜料粒径识别。以敦煌莫高窟壁画为例验证了该方法的可行性。     

植物色素的光声光谱研究

测定了纸色谱分离的极为微量的六种植物色素的光声光谱，并与相应色谱斑点溶出物的吸收光谱进行对照，表明光声光谱对植物色素的鉴定简便有效，海藻类别众多，所含色素体系各有特征，本文报道了绿色藻，红藻和褐藻的光声光谱，并用导数光谱法明确了这些藻类的色素分布特征。     

Altered state of primordial follicles in neonatal and early infantile rats due to maternal hypothyroidism: Light and electron microscopy approach

Thyroid hormones (TH) are one of the key factors for normal prenatal development in mammals. Previously, we showed that subclinical maternal hypothyroidism leads to premature atresia of ovarian follicles in female rat offspring in the pre-pubertal and pubertal periods. The influence of decreased concentration of TH on primordial follicles pool formation during neonatal and early infantile period of rat pups was not investigated previously. Maternal hypothyroidism during pregnancy has irreversible negative influence on primordial follicles pool formation and population of resting oocytes in female rat offspring. The study was done on neonatal and early infantile control (n-10) and hypothyroid (n-10) female rat pups derived from control (n-6) and propylthiouracil (PTU) treated pregnant dams (n-6), respectively. Ovaries of all pups were removed and processed for light and transmission electron microscopy (TEM). Number of nests, oogonia and oocytes per nest, primordial, primary, secondary and preantral follicles were determined. Screening for overall calcium presence in ovarian tissue was done using Alizarin red staining. Morphology and volume density of nucleus, mitochondria and smooth endoplasmic reticulum (sER) in the oocytes in primordial follicles was also assessed. Caspase-3 and terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL), both markers for apoptosis, and proliferating cell nuclear antigen (PCNA) for proliferation were determined in oocytes and granulosa cells in different type of follicles. In neonatal period, ovaries of hypothyroid pups had a decreased number of oogonia, oocytes and nests, an increased number of primordial follicles and a decreased number of primary and secondary follicles, while in early infantile period, increased number of primary, secondary and preantral follicles were found. Alizarin red staining was intense in hypothyroid neonatal rats that also had the highest content of dilated sER. Number of mitochondria with altered morphology in both groups of hypothyroid pups was increased. Apoptosis markers have not shown significant difference between groups but PCNA had an increased expression in the oocytes and granulosa cells in primordial follicles of hypothyroid rats. Light and electron microscopy analysis indicate that previously detected premature ovarian follicular atresia in pre-pubertal and pubertal hypothyroid rats is preceded with premature formation of primordial follicles followed by slight changes on sER and mitochondria in examined oocytes, and increased expression of PCNA.     

How do ovarian follicles interact? A many-body problem with unusual symmetry and symmetry-breaking properties

The assumption that hormonal feedback regulates ovarian follicle growth is used to formulate a many-body problem in which interactions are spatially independent. This mechanism of interaction is shown to be sufficient to account for the regulation of ovulation number. A method is also developed to test if this assumption is consistent with the observed spatial distribution of follicles in the Rhesus monkey ovary.     

Ultrastructure of the human retina in aging and various pathological states

Vision is hampered in aging and diseases, such as age-related macular degeneration, retinitis pigmentosa, diabetic retinopathy and glaucoma. This review collates the fine structural alterations of the human retina in aging and various pathological situations and their links to the disease pathogenesis. It transpires that most changes occur at the level of the retinal pigment epithelium -Bruch's membrane and the photoreceptor layer, causing visual problems to the sufferers. These changes include loss of normal, essential features of these cells and their gradual disappearance. It is important to understand in depth the selective vulnerability of this retinal region to alterations in aging and diseases. Evidence indicates that some of these changes may be mediated by the effects of oxidative stress, inflammation, and chronic light exposure. There are changes also in the inner retinal layers, wherein hypertension, auto-immunity, hypoxia and ischemia could play significant roles in disease pathogenesis. Results of extensive research utilizing animal models have broadened our idea about photoreceptor pathology. However, equivalent knowledge on various changes in aging human retina and in dystrophies that affect the macula is not complete. Since cone photoreceptor and ganglion cell death are a potential problem, it is imperative to know about the basic facts on how they are affected and the mechanisms involved in their death. Thus, prevention of cone and ganglion cell loss should be the target of choice. This review also highlights the significant role played by electron microscopy in understanding such ultrastructural changes and future strategies utilizing it and other techniques to fill some of the existing lacunae and advance our knowledge.     

Analysis of Heavy Metals in Scalp Hair Samples of Hypertensive Patients by Conventional and Microwave Digestion Methods

The abnormal metabolism of metal ions plays an important role in health and disease conditions, and studies about them have been attracting significant interest. The aim of our study was to assess the heavy metals (cadmium, copper, iron, nickel, chromium, lead, and zinc) in scalp hair samples of 200 hypertensive (HT) patients of an urban population together with 215 non‐hypertensive male subjects in the age group of 30–60 years. Hair samples were digested with conventional wet ashing and microwave digestion. Analyses of both digests were done by flame and graphite furnace atomic absorption spectrometry. The validity of methodology was checked by use of the certified reference material (CRM 397) hair, provided the Community Bureau of Reference, Commission of the European Communities. According to a statistical evaluation of the results, the microwave digestion method was a valid alternative to the conventional acid digestion method, p value >0.05, but it gave a faster digestion. The overall metal recoveries were 96–98% of those obtained with microwave digestion. Among the toxic elements determined, levels of nickel, cadmium, copper, chromium, and lead in scalp hair samples of hypertensive patients were significantly higher compared normal male subjects, whereas the essential elements such as iron and zinc were found to be low compared age‐matched non‐hypertensive subjects.