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1.
J Environ Manage ; 353: 120295, 2024 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-38330839

RESUMEN

This paper examines the socio-ecological resilience within China's Northeast National Forest Region (NNFR), focusing on the implications of climate change for forest management and carbon sequestration. It offers a critical assessment of the Natural Forest Protection Program (NFPP) and the associated logging ban policy, recognizing their pivotal contributions to forest conservation but also identifying the shortcomings of a one-size-fits-all approach. Integrating panarchy theory, the study proposes sustainable management practices that align ecological dynamics with societal needs, emphasizing nature-based solutions. The overarching aim is to bolster the long-term resilience and enhance the carbon sequestration potential of the NNFR's forests. It aims to inform global environmental strategy with lessons from the NNFR, advocating for integrated approaches that ensure both ecological sustainability and community prosperity. This approach seeks to provide a comprehensive and effective strategy for addressing environmental challenges, ensuring both ecological integrity and community well-being.


Asunto(s)
Ecosistema , Resiliencia Psicológica , Bosques , Secuestro de Carbono , China , Conservación de los Recursos Naturales
2.
J Ophthalmol ; 2024: 3394425, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38370869

RESUMEN

Purpose: This study was designed to review the primary sites, clinical manifestations, imaging features, treatments, and outcomes of 36 patients with orbital metastasis in North China. Methods: This was a retrospective review of 36 patients with orbital metastasis at Tianjin Eye Hospital between January 2010 and December 2020 in North China as well as a review of the literature. Results: Thirty-six patients were included in the study; 17 were male, and 19 were female, with an age range of 1-82 years (average 54.9 ± 19.8 years). All the tumours were unilateral. The mean duration from the onset of orbital signs to presentation at the hospital was 2.4 months (range 1-10 months). Breast carcinoma, gastrointestinal tract carcinoma, and lung carcinoma were the most common histological types. Proptosis, ocular pain, and diplopia were the most common clinical manifestations. The superior orbit was the most common quadrant involved. All patients received comprehensive therapy, including surgery, radiotherapy, or chemotherapy. The average follow-up time was 2.45 years (range 7 months to 5.5 years). Ten patients in this study died as a result of disseminated metastasis from the primary tumour. Conclusions: In North China, the most common primary cancer that metastasizes to the orbit is breast cancer, followed by gastrointestinal tract carcinoma and lung cancer. The increasing trend of orbital gastrointestinal tract metastases in North China in recent years is noteworthy. The survival rate of patients with orbital metastasis of neuroblastoma is low.

3.
BMC Ophthalmol ; 22(1): 500, 2022 Dec 20.
Artículo en Inglés | MEDLINE | ID: mdl-36539768

RESUMEN

BACKGROUND: The middle turbinate axilla (MTA) has always been used as a stable anatomic landmark for endoscopic surgeons to locate the lacrimal sac on the lateral nasal wall. Yet, little is known about whether the lacrimal sac size will affect the positioning effect of MTA on lacrimal sac. The aim of this study was to investigate the regularity of lacrimal sac size and lacrimal sac localization through the reference position of the MTA on computed tomographic dacryocystography (CT-DCG) images. METHODS: A series of 192 endoscopic dacryocystorhinostomy (DCR) surgeries were performed. All the patients had been diagnosed as unilateral nasolacrimal duct obstruction and received CT-DCG examinations. According to the maximum transverse diameter of the lacrimal sac on CT-DCG, the patients were classified into three groups. Measurements were taken on CT-DCG parasagittal images. RESULTS: The average distance from the sac superior fundus (SSF) to the MTA was 7.52 mm ± 3.23 mm, and it increased with the increase of the maximum transverse diameter of the sac among groups (p < 0.01). The average distance from the common canaliculus (CC) to the MTA was 3.95 mm ± 2.49 mm. No significant difference was observed among the groups (p = 0.11). The average distance from the CC to the SSF was 3.41 mm ± 1.31 mm, and it increased with the increase of the sac transverse diameter among groups (p < 0.01). CONCLUSIONS: The lacrimal sac can be accurately located on the lateral nasal wall by the reference position of the MTA on CT-DCG images. The distance of the SSF to the MTA and the SSF to the CC is related to the lacrimal sac size. The relative position of the CC to the MTA is relatively stable on CT-DCG images, which make it possible to locate the lacrimal sac of different sizes and the corresponding nasal mucosa incision design in endoscopic DCR.


Asunto(s)
Dacriocistorrinostomía , Aparato Lagrimal , Obstrucción del Conducto Lagrimal , Conducto Nasolagrimal , Humanos , Conducto Nasolagrimal/diagnóstico por imagen , Conducto Nasolagrimal/cirugía , Obstrucción del Conducto Lagrimal/diagnóstico por imagen , Cornetes Nasales/diagnóstico por imagen , Cornetes Nasales/cirugía , Dacriocistografía , Axila , Valores de Referencia , Dacriocistorrinostomía/métodos , Tomografía Computarizada por Rayos X
4.
J Ophthalmol ; 2022: 6780901, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35573811

RESUMEN

Purpose: We performed a systematic review and meta-analysis to evaluate the association between cataract surgery and the development and progression of AMD. Methods: This meta-analysis was registered at PROSPERO (CRD42017077962). We conducted a systematic literature search in August 2020 in Embase and PubMed and included cohort studies, case-control studies, or randomized controlled trials (RCTs) if they examined the association between cataract surgery and AMD. Odds ratio (OR) was used as a measure of the association with a random effect model. The analysis was further stratified by factors that could affect the outcomes. Results: 15 studies were included in this study. In the overall analysis, cataract surgery was significantly associated with the incidence of late AMD (OR, 1.80; 95% CI, 1.26-2.56; P = 0.001), particularly geographic atrophy (OR, 3.20; 95% CI, 1.90-5.39; P ≤ 0.001). No significant associations were observed between cataract surgery and the incidence of early AMD. Subgroup analysis showed that the OR for incidence of early and late AMD was significantly higher for cataract surgery performed more than 5 years compared with less than 5 years. We also found an increased risk of progression of AMD after cataract surgery performed more than 5 years (OR, 1.97; 95% CI, 1.29-3.01; P = 0.002). Conclusions: Our results suggest that cataract surgery may be associated with an increased risk of late AMD development and AMD progression. In addition, increasing the follow-up time since cataract surgery may further increase the risk for the development and progression of AMD. In the future, prospective multicenter studies with well-designed RCTs are required to confirm our findings.

5.
Opt Express ; 30(5): 8345-8355, 2022 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-35299577

RESUMEN

In this paper, we make a comprehensive study on tailoring the spectrum and transverse mode of random fiber lasers (RFLs). By simply temperature tuning, the mode gain profile of RFL can be flexibly and precisely manipulated. The spectrum of laser output can be easily tailored in single-wavelength, dual-wavelength, and three-wavelength, respectively. Meanwhile, the operating transverse mode is also optional among LP01 mode, LP11 mode, and hybrid mode. The slope efficiency of 17.9% and 27.3% are obtained for LP11 mode and LP01 mode operation, respectively. Besides, the coherence control can be confirmed by making speckle contrast measurements. This high-efficiency RFL with the customizable spectrum and spatial mode would have unique applications in wavelength or mode division multiplexing systems, speckle-free imaging, secure communication, and information encryption.

6.
Opt Express ; 30(2): 1641-1650, 2022 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-35209320

RESUMEN

In this paper, an oscillating transverse mode switchable mode-locked fiber laser with a few-mode fiber linear cavity is proposed and demonstrated. An artificial filter is used to realize the mode gain modulation of the laser. The stable mode-locked pulsed operation with switchable wavelength is easily achieved and the oscillating transverse mode can be flexibly switched between the fundamental mode and high-order mode by adjusting the polarization controller. The mode-locked fiber laser directly oscillates in the high-order mode stably with a slope efficiency of as high as 12%, and the corresponding operating wavelength, repetition rate as well as pulse duration are 1054.07 nm, 22.662 MHz, 31.5 ps, respectively. Besides, a cylindrical vector beam with a high mode purity of 98.6% is obtained by removing the degeneracy of the LP11 mode. This compact and high-efficiency mode-locked fiber laser operating in switchable transverse mode has the potential application for laser processing, particle trapping, bioimaging, and mode division multiplexing system.

7.
Acta Ophthalmol ; 100(6): e1189-e1198, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34918472

RESUMEN

To compare the effects of different treatment modalities on active, moderate-to-severe Graves' orbitopathy (GO). We searched PubMed and Embase for randomized controlled trials published up to 30 Nov 2020, of different modalities for the treatment of active, moderate-to-severe GO. We performed Bayesian network meta-analyses. This study is registered with PROSPERO (CRD42020166287). Fifteen RCTs were identified. Network meta-analysis showed that in comparison with placebo, teprotumumab, mycophenolate plus intravenous glucocorticoids (IVGCs), mycophenolate, rituximab, azathioprine, IVGCs, orbital radiotherapy, oral glucocorticoids (OGCs) were effective treatments (ordered from most effective to least effective). Teprotumumab was more efficacious in reducing proptosis than IVGCs. No significant difference in changes in diplopia grade was recorded between teprotumumab, rituximab, orbital radiotherapy and IVGCs. Low (4.5-5 g), middle (6 g) and high (7-8 g) cumulative doses of IVGCs were shown to be more effective than OGC in improving the overall response rate, but the very low-group (<3 g) seemed to have a lower risk of adverse events. We found that teprotumumab offered the highest level of efficacy in terms of the overall response rate and was more efficacious in reducing proptosis than IVGCs. With regard to different dosages of IVGCs, the cumulative dose of 4.5-5 g of IVGCs seems to be the most appropriate schedule in terms of efficacy and safety outcomes. Due to the limited number of patients treated with teprotumumab and the lack of comparison with other effective therapeutics, teprotumumab might not become the standard first-line therapy for active, moderate-to-severe GO.


Asunto(s)
Exoftalmia , Oftalmopatía de Graves , Teorema de Bayes , Exoftalmia/inducido químicamente , Exoftalmia/tratamiento farmacológico , Glucocorticoides , Oftalmopatía de Graves/tratamiento farmacológico , Humanos , Metaanálisis en Red , Rituximab/uso terapéutico
8.
Opt Express ; 28(26): 38973-38982, 2020 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-33379455

RESUMEN

Random fiber lasers are of tremendous interest to diverse applications for optical fiber sensing, speckle-free imaging. To date, random fiber lasers with fundamental mode oscillation have been well developed. However, controllable oscillating spatial mode in random fiber lasers have not been reported yet. Here, we propose and demonstrate a few-mode random fiber laser with a switchable oscillating spatial mode based on mode injection locking. An external signal light is injected to realize the locking of transverse mode in this random fiber laser and the direct oscillations of the fundamental mode, hybrid mode, and high order mode can be realized, respectively. This random fiber laser operates in the high-order LP11 mode stably with a threshold of as low as 88 mW. High efficiency and high purity cylindrical vector beams can be obtained by removing the degeneracy of the LP11 mode. This work may pave a path towards random fiber lasers with controllable spatial modes for specific applications in mode division multiplexing, imaging, and laser material processing.

9.
Opt Express ; 28(12): 18351-18359, 2020 Jun 08.
Artículo en Inglés | MEDLINE | ID: mdl-32680033

RESUMEN

An all-fiber laser using polarization-maintaining and ring-core fibers that are capable of automatically generating stable TE01 and TM01 modes is proposed and demonstrated experimentally. Two vector-mode coupling long-period fiber gratings (LPFGs) fabricated by a high-frequency CO2 laser are used in the fiber laser to realize efficient coupling between HE11 mode and TE01/TM01 mode. The polarization dependence of the LPFGs is simulated using the coupled-mode theory and verified by experiments. A ring-core fiber is employed to support the stable propagation of TE01 and TM01 modes. By carefully aligning the polarization direction of the input light, the mode coupling ratios of both LPFGs exceed 15 dB. The mode purities of TE01 and TM01 modes are 92.4% and 97.3%, respectively. Owing to the all-polarization-maintaining structure, the laser output is highly stable under environmental disturbance. This laser can be used as a stable cylindrical vector beam source for a wide range of applications, including surface plasmon excitation, optical tweezers, high-resolution metrology and so on.

10.
Exp Eye Res ; 197: 108109, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32565111

RESUMEN

In this study, we established an experimental human corneal stroma model of simulated cornea tissue composed of thin anterior cornea strips layers obtained from small incision lenticular extraction (SMILE) surgery. We investigated the biomechanical effect of ultraviolet-A- riboflavin cross-linking at different depths of corneal stroma model and correlated it with stromal microstructural changes examined by transmission electron microscopy (TEM). Corneal strips were harvested from fresh human corneal lenticules obtained after SMILE surgery. Experimental models (n = 34) were established by superimposing the corneal lenticule strips until their thickness reached close to 500 µm. Corneal cross-linking (CXL) was performed subsequently using standard or accelerated protocol. Elasticity and viscosity were quantified using stress-strain extensometer. TEM was used to visualize the collagen fiber diameter and interfibrillar spacing. The relative change in Young's modulus (rel. ΔE) decreased nonlinearly with increasing stromal depth both in the standard and accelerated groups. Compared to the sham controls, the rel. ΔE in standard and accelerated CXL groups increased significantly in the anterior 400 µm and 275 µm depth, respectively. Also, the relative change in stress (rel. ΔS) was significantly lower after standard and accelerated CXL compared to sham controls. Depth analysis showed similar results for the elastic effect. TEM images showed a small, non-significant increase in fibril diameter. The interfibrillar spacing decreased significantly after standard and accelerated CXL in the anterior-mid stromal region. We noted that the increase of corneal stiffness correlated with decrease in interfibrillar spacing after CXL. The stiffening effect was depth dependent. The effect of accelerated CXL was less in the deep corneal stromal regions compared to standard CXL.


Asunto(s)
Colágeno/farmacología , Sustancia Propia/efectos de los fármacos , Reactivos de Enlaces Cruzados/farmacología , Queratocono/fisiopatología , Fotoquimioterapia/métodos , Riboflavina/farmacología , Sustancia Propia/ultraestructura , Elasticidad , Humanos , Queratocono/tratamiento farmacológico , Queratocono/patología , Microscopía Electrónica de Transmisión , Fármacos Fotosensibilizantes/farmacología , Rayos Ultravioleta
11.
Acta Biomater ; 113: 438-451, 2020 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-32525050

RESUMEN

Corneal collagen cross-linking (CXL) treatment can restore vision in patients suffering from keratoconus and corneal injury, by improving the mechanical properties of the cornea. The correlation between ultraviolet-A (UVA) irradiant energies of standard CXL (SCXL) and corneal visco-hyperelastic mechanical behavior remains unknown. In this study, SCXL with four different UVA irradiant energy doses (0-5.4 J/cm2) were administered as part of quantitative treatments of corneal stromal lenticules extracted from young myopic patients via small incision lenticule extraction (SMILE) corneal refractive surgery. Double-strip samples with symmetric geometries were cut simultaneously for SCXL treatment and non-treated control. First, 40 pairs of strips were loaded to failure to assess the mechanical parameters of the material. Then, another 40 pairs were tested using a special uniaxial tensile test including quasi-static loading-unloading, instantaneous loading, and stress relaxation, to determine the visco-hyperelastic mechanical behavior. Upon combining the collagen fibril crimping constitutive model with the quasi-linear viscoelastic model, it was observed that with increasing UVA energy dose, the corneal strength and hyperelastic stiffness were significantly enhanced, while the maximum stretch and viscosity of the cornea were significantly reduced. Considering the quantitative analysis of SCXL and the rehabilitation prediction of keratoconus treatment, the results clarify the biomechanical behavior of human corneal stroma in SCXL clinical surgery. STATEMENT OF SIGNIFICANCE: This study quantitatively analyzes the improvement in the biomechanical properties of young central corneal stroma, due to SCXL treatment with different energies. Furthermore, the correlation between the hyper-viscoelastic mechanical parameters and UVA irradiant energy doses of SCXL are clarified. The contribution of this study fills the knowledge gap of the CXL on corneal biomechanics. It can not only clarify this mechanism better but also assist with guiding SCXL surgery for individualized patient corneas.


Asunto(s)
Sustancia Propia , Riboflavina , Fenómenos Biomecánicos , Colágeno , Córnea , Reactivos de Enlaces Cruzados , Humanos , Fármacos Fotosensibilizantes/farmacología , Riboflavina/farmacología , Rayos Ultravioleta
12.
Opt Express ; 28(7): 9988-9995, 2020 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-32225597

RESUMEN

In this paper, we propose a stable orbital angular momentum (OAM) mode fiber laser with an all-polarization-maintaining fiber (PMF) structure based on a combination of two linearly polarized modes. The mode intensity ratio between the two linearly polarized modes can be adjusted by adopting a double-pump structure. A pair of polarization-maintaining long-period fiber gratings (PM-LPFGs) are used as a mode converter. The number of topological charges of the OAM mode beam can be tuned between +1 and -1 by stretching the fiber. By adopting an all-PMF structure, we can build an OAM mode fiber laser without a polarization controller and that is resistant to environmental disturbances. The purity of the OAM mode was approximately 93.6%. This stable and compact OAM mode fiber laser can be used as a laser source in practical applications and scientific research.

13.
J Mech Behav Biomed Mater ; 103: 103575, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-32090903

RESUMEN

To relate the crimping morphology of collagen fibrils to macroscopic hyperelastic responses, a four-parameter collagen fibril crimping constitutive model was developed that characterizes the hyperelastic mechanical properties of ex vivo corneal anterior central stroma from youth patients. The collagen fibril crimping degrees of the corneal stroma follow a Gaussian distribution as observed by transmission electron microscopy of the lenticules extracted from human corneas by small incision lenticule extraction (SMILE) refractive surgery. The hyperelastic parameters of pairs of corneal lenticules from 60 youth myopic patients were determined by tensile stress-stretch curves combined with individual surgical geometric features. The model, whose parameters reflect the corresponding mechanical responses, effectively describes each mechanical deformation process especially the physiological corneal deformation range. The constitutive model was embedded into a UMAT subroutine of the finite element software ABAQUS to simulate the tensile behavior of the corneal stroma, and the differences between individuals was excluded in the statistical analysis. The stromal hyperelastic properties in the two fibril preferential directions were shown to be the same. Although there was no correlation with the degree of corneal myopia, the hyperelastic mechanical properties of both the matrix and collagen fibrils decreased with increasing corneal stromal depth. The results not only have significance for SMILE refractive surgery by elucidating the biomechanical properties of a stromal surgical region but are also conducive to the future biomechanical exploration of the whole human cornea.


Asunto(s)
Sustancia Propia , Miopía , Adolescente , Colágeno , Córnea , Matriz Extracelular , Humanos , Miopía/cirugía
14.
Opt Express ; 27(22): 32649-32658, 2019 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-31684473

RESUMEN

We propose and experimentally demonstrate an ytterbium-doped fiber laser emitting the single high-order cylindrical vector beams with a high efficiency and a high modal purity based on adaptive modal gain control. By the combination of a high-order pump with a self-designed ytterbium-ring doped fiber, modal dependent gain was tailored and specific transverse mode can be selected in the laser cavity. A model based on multimode propagation-rate equations is built up to demonstrate the behaviors of transverse mode competition in the fiber laser. Modal dependent gain of high-order mode pump are simulated numerically, which agree well with our experiment results. The slope efficiency of the fiber laser reaches 79.61% with a low threshold of 47.73mw. The purity of the generated high-order CVBs are in excess of 95%. Such a strategy enables the controllability of modal gain in a fiber laser and reveals the potential to offer a new and promising way to achieve a high-power fiber laser with an arbitrary single high-order transverse modes output.

15.
Opt Express ; 27(20): 27610-27617, 2019 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-31684525

RESUMEN

In this paper, the phenomenon of reverse saturable absorption of offset-spliced graded index multimode fibers (OS-GIMF) is revealed. And based on that, the stable square-shaped and chair-like mode-locked pulses are demonstrated with the maximum pulse energy of 0.14 µJ and 23.8 nJ respectively, while the OS-GIMF acts as a saturable absorber (SA) in fiber laser. By adjusting polarization controller (PC) and the pump power, square-shaped and chair-like pulse can be switched to each other. This multimode SA could sever as high power light source owing to its high damage threshold, compact structure and low cost.

16.
Opt Express ; 26(23): 29679-29686, 2018 Nov 12.
Artículo en Inglés | MEDLINE | ID: mdl-30469929

RESUMEN

We propose and demonstrate an all-fiber laser with LP11 mode output. A transverse mode filter is designed and fabricated to suppress the fundamental mode and enable the fiber laser to oscillate in the second-order (LP11) transverse mode. The mechanism is to introduce relatively low ohmic loss for the TE01 mode and much higher ohmic losses for other modes through the loss of evanescent waves in the metal clad. The fiber laser operates at the center wavelength of 1053.9 nm with a narrow 3 dB linewidth of 0.019 nm. Four states of cylindrical vector mode with high modal purity are obtained through adjusting the intra-cavity polarization controller. This approach has great potentiality and scalability of realizing single high-order mode fiber laser, from which a wide range of applications could benefit.

17.
Graefes Arch Clin Exp Ophthalmol ; 256(11): 2103-2112, 2018 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-30187128

RESUMEN

PURPOSE: The aim of this study was to explore the pathological changes of the nasolacrimal duct in rabbits with experimentally induced obstructive dacryocystitis in correlation with lacrimal endoscopic findings. METHODS: The rabbit model of obstructive dacryocystitis was created by injecting 0.15 ml of self-curing resin into the lacrimal duct. The control group received 0.15 ml of normal saline. Within 16 weeks after the obstructive, lacrimal endoscopy and pathological examination of the nasolacrimal duct were conducted at different time points of 1, 2, 4, 8, and 16 weeks. RESULTS: In the control group, lacrimal endoscopy revealed pink and smooth mucosa; and the pathological analysis revealed an epithelial layer that was composed of superficial columnar cells and a deep basal epithelial layer. The experimental rabbits showed clinical manifestations of obstructive dacryocystitis a week after the injection of self-curing resin. At weeks 1 and 2, the lacrimal endoscopy showed mucosal hyperemia and hemorrhagic spots on the nasolacrimal duct; and the pathological features included epithelial cell swelling and inflammatory cell infiltration. At weeks 4 and 8, the experimental group showed alternatively red and white mucosa under the lacrimal endoscopy, and the pathological features included proliferative epithelium accompanied by papillary hyperplasia. At week 16, the experimental group showed pale and coarse mucosa and white membrane-like layer covering the mucosal surface, and the pathological features included epithelial necrosis, squamous metaplasia, and sub-epithelial fibrosis. CONCLUSION: The mucosa of the nasolacrimal duct showed different pathological features at different time points after lacrimal duct obstruction, which was well correlated with the endoscopic findings. It is possible to predict the pathological stages by the endoscopic observation in NLOD patients.


Asunto(s)
Dacriocistitis/patología , Modelos Animales de Enfermedad , Endoscopía , Obstrucción del Conducto Lagrimal/patología , Conducto Nasolagrimal/patología , Animales , Enfermedad Crónica , Femenino , Fibrosis , Masculino , Membrana Mucosa , Conejos
18.
Int J Ophthalmol ; 11(6): 966-969, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29977808

RESUMEN

AIM: To compare the results of axial length (AL) biometry in cataract eyes by three methods: immersion B-ultrasound (IB) biometry, immersion A-ultrasound (IA) biometry and optical low coherence reflectometry. METHODS: In this prospective observational study of eyes with cataract AL measurements were performed using immersion ultrasound and optical low coherence reflectometry device. The results were evaluated using Bland-Altman analyses. The differences between both methods were assessed using the paired t-test, and its correlation was evaluated by Pearson coefficient. RESULTS: Eighty eyes of 80 patients (39 men and 41 women) for cataract surgery were included in the study. The values of AL could be got from all 80 eyes by IB and IA, the difference of AL measurements between IA and IB was of no statistical significance (P=0.97); the mean difference in AL measurements was -0.031 mm (P=0.26; 95%CI, -0.09 to 0.02); linear regression showed an excellent correlation (r=0.98, P<0.0001). Forty-five of eighty eyes with results of AL measurements, which can be obtained by three methods; the difference of AL measurements was of no statistical significance (IA vs IB, P=0.18; IA vs Lenstar, P=0.51; IB vs Lenstar, P=0.07); linear regression showed an excellent correlation (IA vs IB, r=0.99; IA vs Lenstar, r=0.96; IB vs Lenstar, r=0.96); Bland-Altman analysis also showed good agreement between the two methods [IA vs IB, 95% limits of agreement (LoA), -0.36 to 0.28 mm; IA vs Lenstar, 95% LoA, -0.65 to 0.69 mm; IB vs Lenstar, 95% LoA, -0.55 to 0.68 mm]. CONCLUSION: Measurements with the optical low coherence reflectometry correlated well with IB and IA. In the eyes with serious refractive medium opacity, the measurements of AL could not be achieved or existed deviations when using optical low coherence reflectometry device. Under such circumstances, we should choose IA or IB as the optimization method to obtain measurements, in order to get much more accurate results.

19.
BMC Plant Biol ; 17(1): 247, 2017 Dec 19.
Artículo en Inglés | MEDLINE | ID: mdl-29258443

RESUMEN

BACKGROUND: The trehalose (Tre) pathway has strong effects on growth and development in plants through regulation of carbon metabolism. Altering either Tre or trehalose 6-phosphate (T6P) can improve growth and productivity of plants as observed under different water availability. As yet, there are no reports of the effects of modification of Tre orT6P on plant performance under limiting nutrition. RESULTS: Here we report that nitrogen (N) metabolism is positively affected by exogenous application of Tre in nitrogen-deficient growing conditions. Spraying foliage of tobacco (Nicotiana tabacum) with trehalose partially alleviated symptoms of nitrogen deficiency through upregulation of nitrate and ammonia assimilation and increasing activities of nitrate reductase (NR), glycolate oxidase (GO), glutamine synthetase (GS) and glutamine oxoglutarate aminotransferase (GOGAT) with concomitant changes in ammonium (NH4+) and nitrate (NO3-) concentrations, glutamine and amino acids. Chlorophyll and total nitrogen content of leaves and rates of photosynthesis were increased compared to nitrogen-deficient plants without applied Tre. Total plant biomass accumulation was also higher in Tre -fed nitrogen-deficient plants, with a smaller proportion of dry weight partitioned to roots, compared to nitrogen-deficient plants without applied Tre. Consistent with higher nitrogen assimilation and growth, Tre application reduced foliar starch. Minimal effects of Tre feeding were observed on nitrogen-sufficient plants. CONCLUSIONS: The data show, for the first time, significant stimulatory effects of exogenous Tre on nitrogen metabolism and growth in plants growing under deficient nitrogen. Under such adverse conditions metabolism is regulated for survival rather than productivity. Application of Tre can alter this regulation towards maintenance of productive functions under low nitrogen. This has implications for considering approaches to modifying the Tre pathway for to improve crop nitrogen-use efficiency and production.


Asunto(s)
Nicotiana/crecimiento & desarrollo , Nitrógeno/deficiencia , Trehalosa/metabolismo , Regulación hacia Arriba , Proteínas de Plantas/metabolismo , Nicotiana/enzimología , Nicotiana/metabolismo
20.
Appl Opt ; 56(10): 2661-2666, 2017 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-28375226

RESUMEN

A fiber laser injection system used as a seeder for a high-power laser facility of inertial confinement fusion was designed to meet stringent requirements. Herein, we demonstrate the fiber laser injection system, whose output single-pulse energy reaches the millijoule class. With two-stage amplitude modulators, the system produces a pulse with a higher pulse shaping capability. In addition, amplifying the pulse with large-mode-area fiber and single polarization, large-mode-area photonic crystal fiber (PCF) ensures a good beam quality output. In this proof-of-principle experiment, the long-term stability of FM-to-AM modulation and pulse energy is demonstrated. The successful demonstration of this laser injection system holds great significance for future high-power laser drivers.

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