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1.
Zhonghua Xin Xue Guan Bing Za Zhi ; 51(10): 1069-1074, 2023 Oct 24.
Article in Chinese | MEDLINE | ID: mdl-37859359

ABSTRACT

Objective: This study aimed to analyze clinical factors related to arterial stiffening and establish a risk prediction nomogram of arterial stiffening in the octogenarian(≥80 years). Methods: This study was a retrospective cross-sectional study, which enrolled the octogenarian elderly who underwent physical examination and secondary prevention intervention in the outpatient department of Chinese People's Liberation Army General Hospital from April 2022 to August 2022. Clinical data including demographics, biochemical indicators and medical history were collected. Brachial-ankle pulse wave velocity (baPWV) was detected during the clinical visit. Participants were divided into the control group (baPWV≤1 800 cm/s) and vascular sclerosis group (baPWV>1 800 cm/s). The risk factors of arterial stiffness were analyzed by univariate and logistic regression analysis, and the nomogram model was constructed by R programming language. The predictive effect of the nomogram model was evaluated by the receiver operating characteristic curve (ROC). Results: The median age of the 525 participants was 87.0 (82.0, 92.0) years, 504 (96.0%) were male, 82 in the control group, 443 in the vascular sclerosis group. The baPWV, age, systolic blood pressure, mean arterial pressure and diastolic blood pressure were significantly lower in the control group than those in the vascular sclerosis group (all P<0.05). Logistic regression analysis showed that high-density lipoprotein cholesterol, alanine aminotransferase and amylase were protective factors, and alkaline phosphatase and creatinine were risk factors of arterial stiffening (all P<0.05). The combined nomogram model scores including age, mean arterial pressure and the above five laboratory indicators indicated that mean arterial pressure and serum creatinine levels were strongly correlated with vascular sclerosis. The ROC curve suggested that the nomogram model had good prediction ability. Conclusions: Age, mean arterial pressure, high-density lipoprotein cholesterol, alanine aminotransferase, alkaline phosphatase, amylase and creatinine are independently determinants for increased vascular stiffness. The combined prediction model in this study can provide reference for individualized clinical risk prediction of vascular sclerosis in the octogenarian elderly.


Subject(s)
Ankle Brachial Index , Vascular Stiffness , Aged, 80 and over , Humans , Male , Aged , Female , Vascular Stiffness/physiology , Octogenarians , Retrospective Studies , Cross-Sectional Studies , Alanine Transaminase , Alkaline Phosphatase , Creatinine , Sclerosis , Pulse Wave Analysis , Risk Factors , Amylases , Lipoproteins, HDL , Cholesterol
2.
Zhonghua Yan Ke Za Zhi ; 57(6): 426-432, 2021 Jun 11.
Article in Chinese | MEDLINE | ID: mdl-34098691

ABSTRACT

Objective: To identify factors associated with persistent subretinal fluid (SRF) after scleral buckling and to evaluate surgical outcomes of patients with primary rhegmatogenous retinal detachment (RRD). Methods: Cross-sectional study and cohort study. This study included 104 patients (104 eyes) who underwent scleral buckling for repair of RRD between January 2016 and June 2017. Several statistically significant risk factors associated with SRF were screened out with univariate analysis. Then independent risk factors were determined with multivariate stepwise logistic regression analysis. Examinations were taken preoperatively, at 1, 3, 6, and 12 months postoperatively, and thereafter every six months. Patients were divided into two groups depending on the presence or absence of persistent SRF on optical coherence tomography at 1 month. Results: Persistent SRF occurred in 69.2% (72/104) of patients. In multivariate analysis, younger age (OR=32.860, 95%CI=3.636-296.986, P=0.002), high myopia (OR=7.229, 95%CI=1.217-42.94, P=0.03) and macula-involving retinal detachment (OR=357.397, 95%CI=29.761-4292.0, P=0.000) were associated with persistent SRF. Best corrected visual acuity in patients with SRF at 1 month (0.71±0.18 vs. 0.58±0.11; t=4.047, P<0.01) and 3 months (0.55±0.15 vs. 0.43±0.12; t=3.914, P<0.01) was worse than that in patients with absence of SRF. Best corrected visual acuity in patients with SRF was 0.44±0.16 at 6 months, 0.37±0.12 at 12 months and 0.36±0.10 at the last follow-up, with no significant difference from patients without SRF at the three time points (0.39±0.13, 0.38±0.12 and 0.35±0.09; t=1.643, -0.202, 0.464; P>0.05). Conclusions: RRD patients with younger age, high myopia and macular involvement were more likely to develop persistent SRF after scleral buckling. The presence of persistent SRF slowed visual recovery but did not influence the final visual outcomes. (Chin J Ophthalmol, 2021, 57: 426-432).


Subject(s)
Retinal Detachment , Subretinal Fluid , Cohort Studies , Cross-Sectional Studies , Humans , Logistic Models , Retinal Detachment/surgery , Retrospective Studies , Risk Factors , Scleral Buckling , Tomography, Optical Coherence , Visual Acuity
4.
Zhonghua Yi Xue Za Zhi ; 96(2): 104-7, 2016 Jan 12.
Article in Chinese | MEDLINE | ID: mdl-26792691

ABSTRACT

OBJECTIVES: To investigate the relationship between interleukin-8 levels in expressed prostatic secretion and expressions of basic fibroblast growth factor (bFGF) and Bcl-2 in benign prostatic hyperplasia (BPH). METHODS: A series of 50 consecutive patients diagnosed with BPH and scheduled for transurethral resection of the prostate (TURP) were included. Patients were divided into two groups, simple BPH and BPH with chronic prostatitis (CP). The grade of inflammatory changes in the prostate was then determined blindly by two experienced pathologists, according to the classification system. Expressed prostatic secretion (EPS) was collected right before TURP for IL-8 detection using ELISA kits. The resected prostatic tissue was harvested for immunohistochemistry to measure the expression of Bcl-2 and bFGF. RESULTS: A total of 30 (60%) patients were confirmed to have prostatic histologic inflammation. The volume of the prostate in BPH with CP was obviously larger than that in simple BPH (P=0.022). The NIH chronic prostatitis symptom index (NIH-CPSI) and international prostate symptom score (IPSS) of BPH with CP were both higher than those of simple BPH (P<0.05). Significantly increased levels of IL-8 were observed in EPS obtained from BPH patients with CP (mean level, 43.29 ng/L), compared with patients with simple BPH (mean level, 36.90 ng/L) (P=0.003). The expression of Bcl-2 in BPH with CP (mean level, 6.17) increased significantly, compared with those in simple BPH (mean level, 2.45) (P=0.013). The expression of bFGF in BPH with CP (mean level, 7.57) also obviously elevated, compared with those in simple BPH (mean level, 5.05) (P=0.008). Correlation coefficients of IL-8 levels in EPS and expression of Bcl-2 or bFGF indicated that IL-8 had strong correlation with Bcl-2 and bFGF respectively both in simple BPH and BPH with CP (0

Subject(s)
Prostatic Hyperplasia , Chronic Disease , Fibroblast Growth Factor 2 , Humans , Immunohistochemistry , Interleukin-8 , Male , Proto-Oncogene Proteins c-bcl-2
5.
Genet Mol Res ; 14(1): 1136-44, 2015 Feb 06.
Article in English | MEDLINE | ID: mdl-25730053

ABSTRACT

The aim of our study was to evaluate the efficacy and safety of two concentrations of botulinum toxin A (BTX-A) for the treatment of hemifacial spasm. We randomly divided 20 patients with hemifacial spasm into high- and low-concentration groups; they were administered 50 and 25 U/mL BTX-A injection, respectively. Further, we compared the curative effects and the occurrence of adverse reactions in the two groups. Our results showed that both the concentrations of BTX-A were effective and no significant difference was observed in the onset time and therapeutic efficacy between the two groups; however, the duration of efficacy was longer in the high-concentration group than in the low-concentration group. Patients in both groups had no allergic reactions and systemic toxic reactions, but those in the high-concentration group had more serious adverse reactions and they lasted for longer durations. The adverse reactions in the two groups were not specifically treated, and they resolved in a relatively short time. In conclusion, local injection of BTX-A was effective in treating hemifacial spasm and each concentration of BTX-A had advantages and disadvantages, which indicated that the concentration of BTX-A can be selected according to the clinical characteristics and willingness of the patients.


Subject(s)
Botulinum Toxins, Type A/administration & dosage , Hemifacial Spasm/drug therapy , Adult , Botulinum Toxins, Type A/adverse effects , Cross-Over Studies , Double-Blind Method , Drug-Related Side Effects and Adverse Reactions/pathology , Female , Hemifacial Spasm/pathology , Humans , Male , Middle Aged
6.
Lett Appl Microbiol ; 55(2): 128-34, 2012 Aug.
Article in English | MEDLINE | ID: mdl-22691226

ABSTRACT

AIMS: To investigate the effects of nisin on lactobacilli contamination of yeast during ethanol fermentation and to determine the appropriate concentration required to control the growth of selected lactobacilli in a YP/glucose media fermentation model. METHODS AND RESULTS: The lowest concentration of nisin tested (5 IU ml(-1) ) effectively controlled the contamination of YP/glucose media with 10(6) CFU ml(-1) lactobacilli. Lactic acid yield decreased from 5.0 to 2. 0 g l(-1) and potential ethanol yield losses owing to the growth and metabolism of Lactobacillus plantarum and Lactobacillus brevis were reduced by 11 and 7.8%, respectively. Approximately, equal concentrations of lactic acid were produced by Lact. plantarum and Lact. brevis in the presence of 5 and 2 IU ml(-1) nisin, respectively, thus demonstrating the relatively higher nisin sensitivity of Lact. brevis for the strains in this study. No differences were observed in the final ethanol concentrations produced by yeast in the absence of bacteria at any of the nisin concentrations tested. CONCLUSIONS: Metabolism of contaminating bacteria was reduced in the presence of 5 IU ml(-1) nisin, resulting in reduced lactic acid production and increased ethanol production by the yeast. SIGNIFICANCE AND IMPACT OF THE STUDY: Bacteriocins represent an alternative to the use of antibiotics for the control of bacterial contamination in fuel ethanol plants and may be important in preventing the emergence of antibiotic-resistant contaminating strains.


Subject(s)
Bacteriocins/pharmacology , Ethanol/metabolism , Industrial Microbiology , Lactobacillus plantarum/drug effects , Lactobacillus/drug effects , Nisin/pharmacology , Saccharomyces cerevisiae/metabolism , Fermentation , Lactic Acid/biosynthesis , Lactic Acid/metabolism , Lactic Acid/pharmacology , Lactobacillus/growth & development , Lactobacillus plantarum/growth & development
7.
Acta Pharmacol Sin ; 22(6): 549-55, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11747763

ABSTRACT

AIM: To assess the merits of polyethylene glycol-modified recombinant human tumor necrosis factor alpha (PEG-rHuTNF-alpha). METHODS: The rHuTNF-alpha was modified with N-succinimidyl succinate monomethoxy polyethylene glycol (SS-PEG) of three different molecular weights. The PEG-rHuTNF-alpha was separated into fractions of various molecular weights by gel filtration chromatography. In vitro activities of various fractions were determined with L929 cell assay and in vivo anti-tumor potencies of main fractions were studied with respect to necrosis of S-180 solid tumor. RESULTS: The rHuTNF-alpha could be modified using SS-PEG under mild conditions. The main fraction of PEG5000-rHuTNF-alpha contained four PEG molecules, and PEG12000-rHuTNF-alpha and PEG20000-rHuTNF-alpha contained two PEG molecules, respectively. There was a higher activity when rHuTNF-alpha was coupled to less numbers of the same molecular weight PEG molecules. When PEG-rHuTNF-alpha was of the same molecular weight, rHuTNF-alpha modified with bigger molecular weight PEG molecules had a higher activity. PEG-rHuTNF-alpha was resistant to proteolysis, and over 70 % activity remained after 8 h, but the activity of rHuTNF-alpha was time-dependently diminished by incubation with bovine trypsin. PEG5000-rHuTNF-alpha (1500 IU per mouse) had a similar anti-tumor potency compared with rHuTNF-alpha (3000 IU per mouse). PEG12000-rHuT NF-alpha (1500 IU per mouse) had an increased anti-tumor potency compared with rHuTNF-alpha (3000 IU per mouse). In particular, PEG20000-rHuTNF-alpha at a dose of 1500 IU per mouse had a higher anti-tumor potency than rHuTNF-alpha at a dose of 6000 IU per mouse. CONCLUSION: PEG-modified rHuTNF-alpha could be more suitable for therapeutic use


Subject(s)
Antineoplastic Agents/pharmacology , Tumor Necrosis Factor-alpha/pharmacology , Animals , Male , Mice , Polyethylene Glycols , Protein Processing, Post-Translational , Recombinant Proteins/chemistry , Recombinant Proteins/pharmacology , Sarcoma 180/drug therapy , Sarcoma 180/pathology , Succinimides , Tumor Cells, Cultured/drug effects , Tumor Necrosis Factor-alpha/chemistry
8.
Acta Pharmacol Sin ; 22(7): 645-50, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11749831

ABSTRACT

AIM: To synthesized poly(methoxypolyethyleneglycol cyanoacrylate-co-n-hexadecyl cyanoacrylate) (PEGylated PHDCA) with polyethylene glycol (PEG, Mr = 5000), prepare PEGylated PHDCA and poly(n-hexadecyl cyanoacrylate) (PHDCA) nanoparticles loading salvicine and determine their in vitro characterizations. METHODS: The structure of PEGylated PHDCA was determined with 1H-NMR, 13C-NMR and Fourier transform infrared spectrum (FTIR). Its molecular weight was determined by gel permeation chromatography (GPC). Nanoparticles were prepared by emulsion/solvent evaporation method. RESULTS: 1H-NMR, 13C-NMR, and FTIR were consistent with structure of PEGylated PHDCA, whose average molecular weight is 6680. Entrapment efficiency could be determined by high pressure liquid chromatography (HPLC) method without endogenous interference at the retention time of salvicine. The entrapment efficiency was 92.6 % for PEGylated PHDCA nanoparticles and 98.9 % for PHDCA nanoparticles. The nanoparticles size was about 250 nm. The values of the zeta potential were obviously influenced by the composition of the copolymer. Compared with PHDCA nanoparticles (-23.1 mV), PEGylated PHDCA nanoparticles showed a low surface potential (-9.6 mV). Salvicine release from nanoparticles showed an initial burst effect, then a plateau for an extended period, and finally sustained release phase. CONCLUSION: These results showed that the PEGylated PHDCA nanoparticles could be an effective carrier for salvicine delivery in the respect of anti-tumor potency.


Subject(s)
Cyanoacrylates/chemical synthesis , Naphthoquinones/analysis , Polyethylene Glycols/chemical synthesis , Cyanoacrylates/chemistry , Drug Carriers/chemical synthesis , Drug Carriers/chemistry , Nanotechnology , Naphthoquinones/chemistry , Polyethylene Glycols/chemistry
9.
Biol Pharm Bull ; 24(6): 662-5, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11411555

ABSTRACT

The objective of this study was to investigate the pharmacokinetics and in vivo anti-tumor effect of recombinant human tumor necrosis factor-alpha (rHuTNF-alpha) encapsulated in poly(methoxypolyethyleneglycol cyanoacrylate-co-n-hexadecyl cyanoacrylate) (PEG-PHDCA) nanoparticles. Our experimental results showed that PEG-PHDCA nanoparticles could extend the half-life of rHuTNF-alpha to 7.42 h and obviously change the protein biodistribution in tissues, and in particular, increase accumulation of rHuTNF-alpha in tumor. Compared with PHDCA nanoparticles and free rHuTNF-alpha, PEG-PHDCA nanoparticles loaded with rHuTNF-alpha showed higher antitumor potency at the same dose, which might be related to its higher accumulation in tumor tissues and longer plasma circulation time. Therefore, PEG-PHDCA nanoparticles could be an effective carrier for rHuTNF-alpha.


Subject(s)
Antineoplastic Agents/administration & dosage , Cyanoacrylates/administration & dosage , Tumor Necrosis Factor-alpha/administration & dosage , Animals , Antineoplastic Agents/pharmacokinetics , Antineoplastic Agents/pharmacology , Drug Carriers , Female , Half-Life , Humans , Mice , Polymers , Recombinant Proteins/administration & dosage , Recombinant Proteins/pharmacokinetics , Recombinant Proteins/pharmacology , Tumor Necrosis Factor-alpha/pharmacokinetics , Tumor Necrosis Factor-alpha/pharmacology
10.
Biol Pharm Bull ; 24(6): 666-70, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11411556

ABSTRACT

The aim of the present work was to investigate and assess the merit of PEGylated recombinant human tumor necrosis factor-alpha (rHuTNF-alpha) following our previous work. The rHuTNF-alpha was modified using activated polyethylene glycol (PEG), N-succinimidyl succinnate monomethoxy polyethylene glycol (SS-PEG). The pharmacokinetics and anti-tumor effect were investigated. The experimental results showed that PEGylated rHuTNF-alpha could obviously alter in vivo behavioral characteristics of rHuTNF-alpha. Among the synthesized PEG-rHuTNF-alphas with different PEG molecules, PEG20000-rHuTNF-alpha demonstrated the longest circulating half-life (24.8 h) which was about 50 times longer than that of rHuTNF-alpha (28.8 min). In addition, there was much more PEG20000-rHuTNF-alpha distributed into tumor tissues than other PEG-rHuTNF-alphas or rHuTNF-alpha with time, and PEG20000-rHuTNF-alpha also showed the highest anti-tumor potency. These results indicated that PEG20000-rHuTNF-alpha was a useful long circulating molecule with selective localization in tumor tissues and enhanced anti-tumor activity of rHuTNF-alpha.


Subject(s)
Tumor Necrosis Factor-alpha/pharmacology , Tumor Necrosis Factor-alpha/pharmacokinetics , Animals , Female , Half-Life , Humans , Mice , Polyethylene Glycols/chemistry , Recombinant Proteins/chemistry , Recombinant Proteins/pharmacokinetics , Recombinant Proteins/pharmacology , Tumor Necrosis Factor-alpha/chemistry
11.
J Control Release ; 71(3): 287-96, 2001 Apr 28.
Article in English | MEDLINE | ID: mdl-11295221

ABSTRACT

The aim of this study was to find an effective carrier for recombinant human tumor necrosis factor-alpha (rHuTNF-alpha). The influence of solvent systems containing poly(methoxy-polyethyleneglycol cyanoacrylate-co-n-hexadecyl cyanoacrylate) (PEGylated PHDCA) on the biological activity of rHuTNF-alpha was investigated. The PEGylated PHDCA nanoparticles loading rHuTNF-alpha were prepared with the double emulsion method. The influence of main experimental factors on the entrapment efficiency was evaluated by the Uniform Design. The physicochemical characteristics and in vitro release of rHuTNF-alpha from the nanoparticles were determined. The results showed that serum albumin such as human serum albumin (HSA) or bovine serum albumin (BSA) could play a protective action on rHuTNF-alpha in the preparation process. At > or =2.0% (w/v) HSA concentration, more than 85% of rHuTNF-alpha activity remained and the role of HSA was not affected by copolymer concentrations from 0.5 to 3.0% (w/v). The entrapment efficiency of the nanoparticles was about 60% and the nanoparticle size was about 150 nm. The nanoparticles were spherical in shape and uniform with the value of the zeta potential about -9 mV. The rHuTNF-alpha release from the nanoparticle showed an initial burst and then continued in a sustained fashion. The results showed that the PEGylated PHDCA nanoparticles could be an effective carrier for rHuTNF-alpha.


Subject(s)
Cyanoacrylates/chemistry , Polyethylene Glycols/chemistry , Tumor Necrosis Factor-alpha/administration & dosage , Chemical Phenomena , Chemistry, Physical , Drug Carriers , Drug Stability , Humans , Microspheres , Recombinant Proteins/chemistry , Solubility , Solutions , Tumor Cells, Cultured
12.
Appl Opt ; 40(24): 4236-42, 2001 Aug 20.
Article in English | MEDLINE | ID: mdl-18360461

ABSTRACT

The enhanced backscattering from organic laser gain media that are bounded with one-dimensional (1-D) and two-dimensional (2-D) rough metal films was investigated. We prepared several organic optical gain materials by doping laser-active dyes in matrices of acrylic polymers. These materials produced efficient and broadband fluorescence emission in the visible wavelengths during the pumping of a pulsed YAG or cw argon laser. These gain materials were sliced and coupled with 1-D or 2-D randomly rough gold films with large slopes. An experimental investigation was carried out with a He-Ne laser as the scattering source and the optical gain provided by a cw argon laser. The enhanced backscattering and the satellite peaks located about the enhanced-backscattering peak were obviously amplified, with their widths narrowed. These experimental results agree well with previous theoretical predictions.

13.
Opt Lett ; 26(10): 663-5, 2001 May 15.
Article in English | MEDLINE | ID: mdl-18040412

ABSTRACT

Coherence theory predicts that the correlation in the fluctuations of a source distribution can cause frequency shifts in the spectrum of the emitted radiation, even when the source is at rest relative to the observer. Recently we measured angular spectrum redistribution, or frequency shifts from a real image of a point source, and further verified the coherent interference effect of a finite-band source.

14.
Opt Lett ; 25(6): 375-7, 2000 Mar 15.
Article in English | MEDLINE | ID: mdl-18059884

ABSTRACT

We report the experimental study of the enhanced backscattering from a random rough surface through a laser dye-doped polymer. The sample is a slice of pyrromethene-doped polymer coupled with a two-dimensional rough gold layer with a large slope. When the sample is illuminated with an s-polarized He-Ne laser and pumped by a cw argon-ion laser, amplified backscattering is observed. The enhanced backscattering peak increases sharply and its width narrows for a sample with low dielectric constant |?(2)|.

15.
Appl Opt ; 39(25): 4684-9, 2000 Sep 01.
Article in English | MEDLINE | ID: mdl-18350059

ABSTRACT

Experimental results are presented for the angular correlation function of far-field speckle patterns scattered in the double passage of waves through a one-dimensional random-phase screen. The theoretical analysis of the symmetry of speckle patterns around the backscattering direction and the motion of the speckle as the source is moved, made by Escamilla et al. [Appl. Opt. 32, 2734 (1993)], are verified in this paper.

16.
Opt Lett ; 23(7): 494-6, 1998 Apr 01.
Article in English | MEDLINE | ID: mdl-18084554

ABSTRACT

We report experimental results that show that the far-field correlation function is sensitive to a small local change in rough-surface geometry, where the speckle spatial correlation rather than the sample ensemble average is adopted. The angular cross-correlation function of the far-field speckles scattered by one-dimensional random rough surfaces is measured when a polarized beam of light is incident upon the rough surface from vacuum, where one part of the surface used is a thin dielectric film deposited upon a glass substrate and the other part is identical to the first except for a localized defect. We envisage application of this sensitivity property to inspection of a sample with a defect by means of speckle mapping.

17.
Appl Opt ; 36(19): 4562-70, 1997 Jul 01.
Article in English | MEDLINE | ID: mdl-18259251

ABSTRACT

We present the experimental results of the angular correlation function of far-field speckle patterns scattered by a one-dimensionally random rough surface of a thin dielectric film on a glass substrate when a polarized beam of light is incident upon the rough surface from vacuum. This surface, which separates the vacuum and the dielectric, is rough enough that only diffused speckles are observed. The experiment for the correlation measurement was set up to make use of a CCD camera to obtain the image of the speckle pattern in the specular direction for each given angle of incidence; the cross-correlation function is then calculated from the digitized images. It is found that the intensity correlation functions exhibit two distinct maxima: one arises from the autocorrelation and the other from the reciprocity condition. It is also found that different scattering processes give rise to quite different correlation functions: multiple-scattering processes produce narrow peaks with secondary maxima and single-scattering processes produce relatively broad peaks.

18.
Appl Opt ; 34(18): 3529-34, 1995 Jun 20.
Article in English | MEDLINE | ID: mdl-21052168

ABSTRACT

It has been known theoretically for a few years that not only a rough metallic surface but also a rough dielectric surface can produce an enhanced backscattering peak. Because of difficulty in the fabrication of one- or two-dimensional rough dielectric surfaces with a high index of refraction, no experiments to date have been able to reveal such a peak in scattering from a rough dielectric surface. We present experimental results showing enhanced backscattering from a free-standing dielectric film and compare them with the results of numerical simulations of such scattering. The vacuum-dielectric interface is a one-dimensional, randomly rough surface, and the dielectric-vacuum interface is approximately planar.The results of the numerical simulations of scattering from a one-dimensional, randomly rough free-standing dielectric film are in qualitative agreement with the experimental data, and it is believed that the main mechanism responsible for the enhanced backscattering peak is the reflection from the flat dielectric-vacuum interface. The coherent addition of a given light path that interacts with the rough dielectric surface at two different points because of its partial reflection from the back surface and its time-reversed partner leads to an enhancement of the intensity of scattering in the retroreflection direction with respect to the intensity of scattering in other directions.

19.
Opt Lett ; 19(9): 604-6, 1994 May 01.
Article in English | MEDLINE | ID: mdl-19844386

ABSTRACT

We have observed the enhanced backscattering of light from a characterized dielectric film deposited upon a glass substrate when the light illuminates the rough surface from the vacuum. The vacuum-dielectric interface is one dimensional, randomly rough, while the dielectric-glass interface is approximately planar. Numerical and experimental studies reveal that the main mechanism responsible for the enhanced backscattering is the constructive interference between two waves that follow reciprocal scattering paths through the dielectric film, which is also strengthened by the multiple scattering from the rough vacuum-dielectric interface.

20.
Appl Opt ; 32(15): 2852-9, 1993 May 20.
Article in English | MEDLINE | ID: mdl-20820451

ABSTRACT

One of the most interesting phenomena associated with the scattering of light from a randomly rough surface is that of enhanced backscattering. This is the presence of a well-defined peak in the retroreflection direction in the angular distribution of an incoherent component of mean scattered intensity of the light scattered from such a surface that is primarily due to the coherent interference of each multiply reflected optical path with its time-reversed partner. It is an example of a broader class of multiple-scattering phenomena that goes under the name of weak localization. Not all manifestations of weak localization in the interaction of light with a randomly rough surface are in backscattering. It was recently shown that the average diffuse intensity from randomly rough surfaces with even symmetry can be enhanced or reduced in the specular direction because of the constructive interference between correlated pairs of scatters. We present a recent theoretical analysis and experimental results that cover four kinds of enhancement: enhanced backscattering, enhanced transmission, enhanced specular, and enhanced refraction for one-dimensional and two-dimensional surfaces. These are manifestations of coherent effects that remain after ensemble averaging.

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