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1.
Zhonghua Yu Fang Yi Xue Za Zhi ; 57(10): 1674-1681, 2023 Oct 06.
Artigo em Zh | MEDLINE | ID: mdl-37859388

RESUMO

The improvement of food labeling can improve consumers' health awareness, reduce the burden of chronic diseases on the health and economy, and promote the development of the healthy food industry. Disease Risk Reduction Claim has been developed in European Union and the U.S. for over 20 years, with mature management methods and experience, but it is still lacking in China. Learning and drawing on the international management experience of food disease risk reduction claims can assist China to establish food disease risk reduction claims and improve the food health claims and labeling system.


Assuntos
Indústria Alimentícia , Rotulagem de Alimentos , Humanos , Estados Unidos , União Europeia , China/epidemiologia
2.
Zhonghua Yu Fang Yi Xue Za Zhi ; 56(9): 1289-1294, 2022 Sep 06.
Artigo em Zh | MEDLINE | ID: mdl-36207893

RESUMO

Objective: To investigate the association between peripheral blood mitochondrial DNA copy number (mtDNAcn) and incident risk of liver cancer. Methods: At the baseline of Dongfeng-Tongji (DFTJ) cohort, 27 009 retirees were recruited from Dongfeng Motor Corporation in 2008. After excluding people without baseline DNA, with current malignant tumor and loss of follow-up, 1 173 participants were randomly selected into a sub-cohort by age-and gender-stratified sampling method at a proportion of 5% among all retirees. A total of 154 incident liver cancer cases identified from the cohort before December 31, 2018 (4 cases had been selected into the sub-cohort) were selected to form the case cohort of liver cancer. For the above 1 323 participants, their baseline levels of mtDNAcn in peripheral blood cells were measured by using quantitative real-time PCR method. The restricted cubic spline analysis was used to fit the shape of the association between baseline mtDNAcn and incident risk of liver cancer. The weighted Cox proportional hazards model was used to estimate the hazard ratio (HR) and 95%CI. Results: In this case-cohort study, the median follow-up time was 10.3 years. The restricted cubic spline analysis indicated that the relationship between peripheral blood mtDNAcn and incident risk of liver cancer followed a U-shaped pattern (Pnon-linear<0.05). All case-cohort population were divided into four subgroups by sex-specific quartiles of mtDNAcn levels among sub-cohort participants, when compared to participants in the Q2 subgroup of mtDNAcn, those in the Q1 subgroup (HR=2.00,95%CI:1.08-3.70) and Q4 subgroup (HR=4.11,95%CI:2.32-7.26) both had a significantly elevated risk of liver cancer, while those in the Q3 subgroup (HR=1.05,95%CI:0.54-2.05) had not. There were no significant multiply interaction effects of aging, gender, tobacco smoking, alcohol drinking and history of chronic hepatitis on the above association (Pinteraction>0.05). Conclusion: Both extremely low and high baseline level of mtDNAcn in peripheral blood cells are associated with an increased risk of incident liver cancer, but the underlying mechanisms need to be further clarified.


Assuntos
DNA Mitocondrial , Neoplasias Hepáticas , Estudos de Coortes , Variações do Número de Cópias de DNA , DNA Mitocondrial/genética , Feminino , Humanos , Neoplasias Hepáticas/epidemiologia , Neoplasias Hepáticas/genética , Masculino , Mitocôndrias
3.
Zhonghua Yi Xue Za Zhi ; 100(25): 1962-1966, 2020 Jul 07.
Artigo em Zh | MEDLINE | ID: mdl-32629597

RESUMO

Objective: To identify predictors of massive blood loss after posterior hemivertebra resection for patients with congenital scoliosis. Methods: The data of 106 children with congenital scoliosis were collected from June 2017 to June 2019 in Beijing Children's Hospital. All the cases received posterior hemivertebra resection and internal fixation. The blood volume was estimated by weight and height. The visible blood loss was recorded according to medical record, and the hidden blood loss was calculated by OSTHEO formula. Perioperative information including age, gender, height, weight, Cobb and kyphosis angle, level fused, number of screws, operative time, and laboratory examinations was collected. Then multivariable linear regression was performed to determine the independent risk factors of blood loss. Results: All the surgeries were completed successfully. The mean age of the children was (7.3±2.3) years and the operative time was (162±56) min. The mean fused levels were 3 and the correction rate for deformity was 78.4%. The amount of blood loss was (568±208) ml which accounted for 42.3% of total blood volume. The visible and hidden blood loss was (334±193) ml and (234±199) ml, respectively, and which accounted for 58.8% and 41.2% of total blood loss. Multivariable linear regression analysis indicated that age, preoperative Cobb angle, the time of surgery and the number of fused levels were independent risk factors of total blood loss. Preoperative Cobb angle ≥40°, spinal fusion ≥4 levels and operative duration ≥140 min indicated more blood loss (all P<0.05). Conclusions: The perioperative blood loss of congenital scoliosis is massive with a high percentage of hidden blood loss. The patients with severe deformity, more fused levels and increased operative time brings higher risk of massive blood loss.


Assuntos
Escoliose , Fusão Vertebral , Perda Sanguínea Cirúrgica , Criança , Pré-Escolar , Humanos , Estudos Retrospectivos , Resultado do Tratamento
4.
Zhonghua Yu Fang Yi Xue Za Zhi ; 50(10): 900-906, 2016 Oct 06.
Artigo em Zh | MEDLINE | ID: mdl-27686769

RESUMO

Objective: To investigate the association and interaction of heat shock proteins B1(HSPB1)gene rs2868371 and tumor-suppressor protein p53(TP53)gene rs1042522 polymorphisms with chromosome damage levels among coke oven workers. Methods: We recruited 1 333 male workers from a state-run coke oven plant in Wuhan in September-October 2010. Among them, 949 who had worked in coke oven workplaces, including auxiliary facilities and bottom, side, and top ovens, were nominated as coke oven workers(i.e., exposed), and 384 administrative or medical staff whose workplaces were offices were used as controls. General characteristics and 5 ml of venous blood were collected from each participant. The plasma concentrations of benzo[a]pyrene-diolepoxide(BPDE)-albumin adducts and the lymphocytic micronucleus(MN)frequencies for each individual were detected by ELISA and cytokinesis-block micronucleus assay, respectively. Gene polymorphisms were genotyped using TaqMan assays via quantitative PCR(ABI Prism 7900HT), and the corresponding frequency ratios(FR)with 95% confidence intervals(CI)were computed for all assays. Results: In the exposed group, the MN frequencies were higher in HSPB1 rs2868371 GC, CC, and GC+ CC genotype carriers((3.88 ± 2.88)‰,(4.00 ± 2.66)‰, and(3.91 ± 2.83)‰, respectively)than in rs2868371 GG genotype carriers((3.52±2.67)‰; FR=1.10, 1.13, and 1.11; 95% CI: 1.02-1.19, 1.02-1.25, and 1.03-1.19, respectively), and the HSPB1 rs2868371C allele was associated with increased MN frequency(Ptrend=0.006). Further, in the exposed group, the MN frequencies were lower in TP53 rs1042522 CG and CG+GG genotype carriers((3.63±2.61)‰ and(3.66±2.61)‰, respectively)than in TP53 rs1042522 CC genotype carriers(3.95±3.06)‰(FR=0.87 and 0.90; 95% CI: 0.83-0.96 and 0.84-0.97, respectively). The effect of gene-gene interaction between HSPB1, rs2868371, and TP53 rs1042522 on MN frequency was significant among coke oven workers(P=0.001). Further stratified analyses showed that the effects of the HSPB1 rs2868371C allele in increasing MN frequencies were robust in subjects aged >40 years(FR=1.07, 95% CI: 1.01-1.12), those working >20 years(FR=1.08, 95% CI: 1.02-1.14), those with BMI ≤24 kg/m2(FR=1.07, 95% CI: 1.01-1.13), drinkers(FR=1.09, 95% CI: 1.02-1.16), and workers with higher BPDE-albumin adduct levels(FR=1.07, 95% CI: 1.01-1.13)(Ptrend=0.023, 0.013, 0.029, and 0.020, respectively). The decreasing effect of the TP53 rs1042522 G allele on MN frequencies was robust in subjects aged >40 years(FR=0.94, 95% CI: 0.89-0.99), those with BMI ≤24 kg/m2(FR=0.94, 95% CI: 0.88-0.99), and drinkers(FR=0.94, 95% CI: 0.88-1.00)(Ptrend=0.031, 0.023, and 0.038, respectively). In addition, there were interactions between HSPB1 rs2868371 and age and between HSPB1 rs2868371 and working years in terms of MN frequency(P=0.030 and 0.013, respectively). Conclusion: In coke oven workers, the HSPB1 rs2868371 C and TP53 rs1042522 G alleles were associated with increased and decreased chromosome damage levels, respectively, and their interaction effect on chromosome damage levels was significant.


Assuntos
Aberrações Cromossômicas , Dano ao DNA , Proteínas de Choque Térmico , MicroRNAs/genética , Exposição Ocupacional , Polimorfismo Genético , Proteína Supressora de Tumor p53 , Adulto , Coque , Genes p53 , Genótipo , Humanos , Masculino , Micronúcleos com Defeito Cromossômico/induzido quimicamente , Testes para Micronúcleos , Polimorfismo de Nucleotídeo Único
5.
J Anim Physiol Anim Nutr (Berl) ; 99(1): 123-131, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24702602

RESUMO

The objective of this study was to evaluate the effects of isobutyrate supplementation on rumen microflora, enzyme activities and methane emissions in Simmental steers consuming a corn stover-based diet. Eight ruminally cannulated Simmental steers were used in a replicated 4 × 4 Latin square experiment. The treatments were control (without isobutyrate), low isobutyrate (LIB), moderate isobutyrate (MIB) and high isobutyrate (HIB) with 8.4, 16.8 and 25.2 g isobutyrate per steer per day respectively. Isobutyrate was hand-mixed into the concentrate portion. Diet consisted of 60% corn stover and 40% concentrate [dry matter (DM) basis]. Dry matter intake (averaged 9 kg/day) was restricted to a maximum of 90% of ad libitum intake. Population of total bacteria, cellulolytic bacteria and anaerobic fungi were linearly increased, whereas that of protozoa and total methanogens was linearly reduced with increasing isobutyrate supplementation. Real-time PCR quantification of population of Ruminococcus albus, Ruminococcus flavefaciens, Butyrivibrio fibrisolvens and Fibrobacter succinogenes was linearly increased with increasing isobutyrate supplementation. Activities of carboxymethyl cellulase, xylanase and ß-glucosidase were linearly increased, whereas that of protease was linearly reduced. Methane production was linearly decreased with increasing isobutyrate supplementation. Effective degradabilities of cellulose and hemicellulose of corn stover were linearly increased, whereas that of crude protein in diet was linearly decreased with increasing isobutyrate supplementation. The present results indicate that isobutyrate supplemented improved microflora, rumen enzyme activities and methane emissions in steers. It was suggested that the isobutyrate stimulated the digestive micro-organisms or enzymes in a dose-dependent manner. In the experimental conditions of this trial, the optimum isobutyrate dose was approximately 16.8 g isobutyrate per steer per day.


Assuntos
Bovinos/fisiologia , Suplementos Nutricionais , Isobutiratos/farmacologia , Metano/metabolismo , Rúmen/microbiologia , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Dieta/veterinária , Relação Dose-Resposta a Droga , Isobutiratos/administração & dosagem , Masculino , Rúmen/enzimologia
7.
Genet Mol Res ; 12(2): 1431-9, 2013 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-23661466

RESUMO

Disc degeneration is strongly associated with back or neck pain, sciatica, and disc herniation or prolapse. It places an enormous economic burden on society and can greatly affect quality of life. Alternative treatment approaches, such as genetic therapies, are urgently needed to slow or reverse the disc degeneration process. We downloaded gene expression data from Gene Expression Omnibus during various stages of disc degeneration and identified differentially expressed genes (DEGs) as well as dysfunctional pathways through comparisons with controls. We identified 2 significant DEGs between grade II and III discs and 8 significant DEGs between grade II and IV discs. By constructing an interactive network of the DEGs, we found that mitogen-activated protein family genes and Ras homologous (Rho) family genes - in particular, MAP2K6 and RHOBTB2 - may play important roles in the progression of degeneration of grade III and IV discs, respectively. MAP2K6 and RHOBTB2 may be specific therapeutic molecular targets in the treatment of disc degeneration. However, further experiments are needed to confirm this result.


Assuntos
Biologia Computacional , Perfilação da Expressão Gênica , Degeneração do Disco Intervertebral/genética , Biologia Computacional/métodos , Bases de Dados de Ácidos Nucleicos , Regulação da Expressão Gênica , Redes Reguladoras de Genes , Estudos de Associação Genética , Humanos , Degeneração do Disco Intervertebral/metabolismo , Transdução de Sinais
8.
Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi ; 31(5): 504-509, 2019 Oct 14.
Artigo em Zh | MEDLINE | ID: mdl-31713379

RESUMO

OBJECTIVE: To investigate the protective effect of excretory-secretory protein (AES) from adult Trichinella spiralis on ovalbumin (OVA)-induced allergic rhinitis in mice. METHODS: Eighteen female BALB/c mice were randomly divided into three groups, including the blank control group (Group A), OVA-induced rhinitis group (Group B) and AES treatment group (Group C). Mice in Group A were given PBS. Mice in Group B were intraperitoneally injected with antigen adjuvant suspension for systemic sensitization, once every other day for seven times; then, local excitation was intranasally induced with 5% OVA solution once a day for seven times to establish a mouse model of allergic rhinitis. In addition to induction of allergic rhinitis, mice in Group C were given 25 µg AES at baseline sensitization and local excitation. Following the final challenge, mice were observed for 30 min in each group, and the behavioral score was evaluated. The serum levels of IFN-γ, IL-4, IL-5, IL-10 and TGF-ß were determined using an enzyme-linked immunosorbent assay in mice, and the pathological changes of mouse nasal mucosa were observed under a microscope. RESULTS: There was a significant difference in the mouse behavioral scores among the three groups (F = 110.12, P < 0.01). The mouse behavioral score was significantly higher in Group B than in Group A (7.17 ± 0.75 vs. 1.33 ± 0.52, P < 0.01), and more remarkable pathological damages of mouse nasal mucosa were seen in Group B than in Group A, while the mouse behavioral score was significantly decreased in Group C than in Group B (P < 0.01), and the pathological damages of mouse nasal mucosa remarkably alleviated in Group C relative to Group B. There was a significant difference in serum IFN-γ level among the three groups (F = 7.50, P < 0.01) and the serum IFN-γ level in Group B was significantly lower than in group A and C (both P < 0.05). There were significant differences in serum IL-4 (F = 470.81, P < 0.01) and IL-5 levels (F =68.20, P < 0.01) among the three groups, and significantly greater serum IL-4 and IL-5 levels were detected in Group B than in Group A (P < 0.01), while significantly lower serum IL-4 and IL-5 levels were detected in Group C than in Group B (P < 0.01). There were significant differences in serum IL-10 (F = 174.91, P < 0.01) and TGF-ß levels (F = 9.39, P < 0.01) among the three groups, and significantly greater serum IL-10 and TGF-ß levels were seen in Group C than in Group B (both P < 0.05). CONCLUSIONS: T. spiralis AES has a remarkable protective activity against OVA-induced allergic rhinitis in mice.


Assuntos
Antígenos de Helmintos , Proteínas de Helminto , Rinite Alérgica , Trichinella spiralis , Animais , Antígenos de Helmintos/imunologia , Antígenos de Helmintos/farmacologia , Modelos Animais de Doenças , Feminino , Proteínas de Helminto/imunologia , Proteínas de Helminto/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Mucosa Nasal/efeitos dos fármacos , Ovalbumina , Rinite Alérgica/induzido quimicamente , Rinite Alérgica/imunologia , Rinite Alérgica/prevenção & controle
9.
J Anim Sci ; 95(11): 5091-5099, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29293704

RESUMO

The objective of this study was to determine the effects of feeding sodium stearoyl-2-lactylate (SSL) as a new feeding emulsifier diet with and without soybean oil (SO) on the milk fat globule (MFG) size, milk composition, digestibility of nutrients, and performance in lactating sows. Sixty sows (Large White × Landrace) were randomly assigned to 1 of 4 treatments according to a 2 × 2 factorial arrangement of treatments. Each treatment had 15 replicates composed of 1 sow. The factors included 1) the fat level (0% vs. 3% SO) and 2) the emulsifier content (0% vs. 0.1% SSL). Treatments included 1) Control (without SO and SSL), 2) SO (3% SO without SSL), 3) SSL (0.1% SSL without SO), and 4) SO + SSL (3% SO and 0.1% SSL). During the suckling period, sows in the SO + SSL group lost less back fat thickness ( < 0.05) compared to other groups; sows fed 3% SO diets consumed less feed ( < 0.05) compared to sows fed diets without SO, but there were no significant effects ( > 0.05) of dietary fat and its interaction with a dietary emulsifier on energy intake and the weaning-estrus interval. The digestibility of ether extract in the SO + SSL group was greater than in the SO group ( < 0.05). Moreover, greater digestibility of CP, Ca, and P in the SO+SSL group was observed compared to that of other groups ( < 0.05). Feeding the SO + SSL diet improved the concentrations of milk fat, protein, and total solids on d 11 of lactation compared to other diets ( < 0.05). Also, an interaction between supplemental SSL and SO was observed for the milk fat and total solids concentrations. The average diameter of MFG on d 11 of lactation was significantly decreased by the addition of 0.1% SSL compared to a diet with no SSL supplementation ( < 0.05). No significant differences among the dietary treatments were observed in cholesterol, triglyceride, high-density lipoprotein cholesterol, or low-density lipoprotein cholesterol in sows' plasma ( > 0.05). In conclusion, feeding a 0.1% SSL diet to lactating sows may decrease the average diameter of MFG and improve the digestibility of nutrients and composition of milk.


Assuntos
Suplementos Nutricionais , Lactação/efeitos dos fármacos , Leite/química , Óleo de Soja/farmacologia , Estearatos/farmacologia , Suínos/fisiologia , Ração Animal/análise , Animais , Dieta/veterinária , Gorduras na Dieta/metabolismo , Digestão/efeitos dos fármacos , Ingestão de Energia/efeitos dos fármacos , Estro/efeitos dos fármacos , Feminino , Glicolipídeos/análise , Glicoproteínas/análise , Gotículas Lipídicas , Suínos/crescimento & desenvolvimento , Desmame
10.
Poult Sci ; 70(4): 766-9, 1991 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-1876555

RESUMO

An experiment was conducted to investigate the performance of four strains of commercial egg type pullets (A, B, C, and D) from 19 to 30 wk of age. The feed consumption differences during this period as well as feed consumption patterns 10 days prior to and after the first oviposition were of special interest. Two hundred and sixty-four birds (66 birds per strain) were fed a diet formulated to contain 2,750 kcal/kg ME, 17% CP, and 3.4% calcium. Results show that the average age to the first egg and percentage of hen-day egg production were not significantly different among the four strains of birds. However, egg weights of Strain A and C birds were significantly heavier than those of the Strain B and D birds. The birds from Strains B and D had significantly lower body weight than Strain A birds at the end of 18 wk, but body weights were not significantly different at the end of 30 wk. Feed intake per bird per day of pullets from Strains A and C was generally higher than that of those from Strains B and D in the first and second 4-wk period. Some of the consumption differences were significant. Feed intake in the third period (27 to 30 wk) was similar for the four strains of birds. Although different strains showed different feed consumption patterns around the first oviposition, all strains showed a drop on the day of the first oviposition. When the strains were combined, feed consumption was lower on that day than during the 8 days prior to the first oviposition.


Assuntos
Galinhas/fisiologia , Ingestão de Alimentos , Oviposição/fisiologia , Animais , Peso Corporal , Feminino
11.
Sheng Li Xue Bao ; 48(4): 405-9, 1996 Aug.
Artigo em Zh | MEDLINE | ID: mdl-9389206

RESUMO

In 56 urethane anesthetized Wistar rats, bilateral microinjection of glutamate (L-glu) was used to observe the difference of cardiovascular effects between caudal ventrolateral medulla pressor area (cVMP) and rostral ventrolateral medulla pressor area (rVMP). The results showed that the pressor effect of cVMP was weaker than that of rVMP and was not accampanied by responses in heart rate. In the latter case, an increase of heart rate was involved. The baroreflex was inhibited when rVMP was activated by L-glu but facilitated when cVMP was activated. The above results suggest that the pathway and functions of the cardiovascular effects of rVMP are different from those of cVMP.


Assuntos
Barorreflexo/fisiologia , Frequência Cardíaca , Bulbo/fisiologia , Pressorreceptores/fisiologia , Animais , Pressão Sanguínea , Glutamatos/farmacologia , Masculino , Microinjeções , Ratos , Ratos Wistar
14.
Br J Radiol ; 82(984): 1027-32, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19366736

RESUMO

The objective of this study was to assess the radiation exposure levels in victims of a (60)Co radiation accident using chromosome aberration analysis and the micronucleus assay. Peripheral blood samples were collected from three victims exposed to (60)Co 10 days after the accident and were used for the chromosome aberration and micronucleus assays. After in vitro culture of the lymphocytes, the frequencies of dicentric chromosomes and rings (dic+r) and the numbers of cytokinesis blocking micronuclei (CBMN) in the first mitotic division were determined and used to estimate radiation dosimetry. The Poisson distribution of the frequency of dic+r in lymphocytes was used to assess the uniformity of the exposure to (60)Co radiation. Based on the frequency of dic+r in lymphocytes, estimates of radiation exposure of the three victims were 5.61 Gy (A), 2.48 Gy (B) and 2.68 Gy (C). The values were estimated based on the frequencies of CBMN, which were 5.45 Gy (A), 2.78 Gy (B) and 2.84 Gy (C). The estimated radiation dosimetry demonstrated a critical role in estimating the radiation dose and facilitating an accurate clinical diagnosis. Furthermore, the frequencies of dir+r in victims A and B deviated significantly from a normal Poisson distribution. Chromosome aberration analysis offers a reliable means for estimating biological exposure to radiation. In the present study, the micronucleus assay demonstrated a high correlation with the chromosome aberration analysis in determining the radiation dosimetry 10 days after radiation exposure.


Assuntos
Síndrome Aguda da Radiação/etiologia , Aberrações Cromossômicas , Radioisótopos de Cobalto/efeitos adversos , Raios gama/efeitos adversos , Liberação Nociva de Radioativos , Adulto , Criança , Exposição Ambiental/efeitos adversos , Exposição Ambiental/análise , Feminino , Humanos , Masculino , Testes para Micronúcleos , Doses de Radiação , Radiometria/métodos
15.
Opt Lett ; 11(11): 724-6, 1986 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-19738740

RESUMO

We demonstrate that frequency-chirped laser excitation pulses may be employed to generate coherent transient signals possessing the same temporal profile as a particular excitation pulse. In comparison with the short, fixedfrequency pulses used in previous studies of this effect, chirped pulses can be temporally longer, of lower intensity, and hence easier to generate. The experiment was performed on the 555.6-nm transition of vapor-phase atomic ytterbium, and pulse-shape information was stored in a coherence between excited-state Zeeman levels. A simple theoretical analysis of our results is presented.

16.
Opt Lett ; 17(15): 1079-81, 1992 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-19794725

RESUMO

We demonstrate the use of stimulated echoes for high-speed phase-modulated signal processing. The specific example chosen here involves the compression of biphase-coded pulses-a technique widely used in radar systems to achieve high range resolution and high signal-to-noise ratios. Experimental results obtained with the 5- and 13-bit Barker codes are presented, along with the measurements of a system's dynamic range and signal-to-noise enhancement. Advantages of this technique over the existing methods for signal processing are discussed.

17.
Opt Lett ; 21(8): 567-9, 1996 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-19876085

RESUMO

We report experimental observation of resonant two-photon photorefractive gratings in Pr-doped SBN:60. Long-lived 4f intermediate states significantly reduced intensity threshold, thus permitting use of cw lasers for the two-photon transitions. Both two-beam one-color two-photon gratings and three-beam two-color gratings were observed. We expect these results to be extended to other rare-earth dopants.

18.
Opt Lett ; 22(5): 334-6, 1997 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-18183193

RESUMO

We have observed efficient two-photon, two-step recording in a praseodymium-doped lithium niobate crystal by use of cw lasers. Single-photon erasure during the readout at near-infrared wavelengths was found to be negligible. Nonvolatile holographic image storage was demonstrated. This progress is an important step in the realization of an economically feasible nonvolatile read-write holographic recording system based on low-cost semiconductor diode lasers.

19.
Opt Lett ; 9(6): 232-4, 1984 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-19721554

RESUMO

Using an acousto-optically gated cw dye laser and working on the 555.6-nm absorption line of atomic(174)Yb, we have studied the shape of two-excitation-pulse photon echoes as a function of the duration and intensity of the second excitation pulse. Surprisingly, a long and intense second excitation pulse is found to generate an echo having a shape highly correlated with that of the first excitation pulse. This occurs because the high field of pulse 2 effectively stops dephasing processes throughout its duration.

20.
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