Influence Of Light Irradiation Research Articles

Influence of Light Irradiation on the Degradation of Dezocine in Injections.

Dezocine, which is well-known as an analgesic, had about 45% share of the Chinese opioid analgesic market. Since drug products containing impurities could bring serious health consequences, it was important to control the generation of impurities and degradation products in the dezocine product. In this study, two kinds of photodegradation products (i.e., degradation product 1 and degradation product 2) in the dezocine injection were isolated using high-performance liquid chromatography. The possible structures of the photodegradation products were identified using both high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy. In addition, the possible generation mechanism showed that degradation product 1 was the oxidation product of dezocine, and degradation product 2 was the coupled dimer of dezocine. Finally, we found that the degradation rate of dezocine increased with the increase in light intensity. Moreover, the degradation of dezocine easily occurred under ultraviolet light in comparison with visible light. A deeper insight into the generation of the photodegradation products in the dezocine injection would directly contribute to the safety of drug therapy based on the dezocine injection by minimizing the degradant/impurity-related adverse effects of drug preparations.

Influence of Light Irradiation on Nitrification in Microalgal–Bacterial Systems for Treating Wastewater

The use of bacterial and microalgal consortia to remove nitrogen from wastewater has garnered attention as a potential alternative to conventional systems. This approach not only reduces energy consumption but also aids in nutrient recovery. Light is essential for algae photosynthesis; however, nitrifying bacteria are also influenced by light radiation. This mini-review summarizes the current knowledge concerning photoinhibition, the light stimulation of ammonia-oxidizing bacteria (AOB), resistance to light radiation, the implementation of microalgal–bacterial systems, and the possible mechanisms involved. Nitrosomonadaceae AOB and Nitrospiraceae nitrite-oxidizing bacteria (NOB) often coexist in a microalgal–bacterial system. Studies have suggested that AOB can tolerate light radiation at 200 μmol m−2·s−1 in microalgal–bacterial systems, whereas NOB are almost completely suppressed, which can result in partial nitrification in the bioreactor. An appropriate light level can stimulate AOB growth in microalgal–bacterial granular reactors and may improve algae metabolic activity. Granular sludges or artificial “light-shielding hydrogel” could effectively protect nitrifying bacteria from light intensities up to 1600 μmol m−2·s−1 in wastewater treatment reactors. Microalgal–bacterial systems along with the associated “algal shading effect” have been widely used in pond aquaculture. This approach minimizes the need for costly mechanical aeration through photo-oxygenation and facilitates nutrient recovery by filter-feeding fish.

Modern outlook for the use of photosensitizers with aggregation-induced emission in treatment of malignant tumors

Photodynamic therapy (PDT) is actively developing, becoming one of the important methods of non-invasive treatment of various oncological and infectious diseases. It is usually carried out using three main components: a photosensitizer, light, and oxygen. The key factors for the effective use of PDT are reactogenic oxygen species, which are produced during the oxidation of photosensitizers under the influence of light irradiation.
 To increase the production of reactogenic oxygen species, a technique was proposed for creating photosensitizers with aggregation-induced emission. At the present stage in oncology, the following PDT methods using photosensitizers with aggregation-induced emission are distinguished: PDT, absorbing near infrared radiation; enzyme- or glutathione-activated PDT; hypoxic PDT, and synergistic therapy.
 Compared to visible light, near infrared radiation (7001700 nm) has been shown to be more effective and safer due to reduced photodamage, less scattering, and deeper light penetration. The development of activated photosensitizers is an effective way to overcome the uncontrolled phototoxicity of photosensitizers during long-term PDT in vivo, providing controlled death of tumor cells. The oxygen concentration in tumor tissue varies depending on tumor progression, angiogenesis, metabolism, and metastasis. Therefore, the development of photosensitizers capable of effectively fluorescing under hypoxic conditions, including catalyzing intracellular substrates with the formation of oxygen and stimulating the production of reactogenic oxygen species through the type I mechanism, has become a potential solution to the problem of PDT of solid tumors.
 The therapeutic efficacy of a single PDT method, as well as most treatment methods in modern oncology, is limited. Therefore, a significant direction is the development of multifunctional treatment systems for synergistic therapy of tumors. Synergistic chemotherapy and PDT is an important area of treatment in oncology. The combination of PDT and immunotherapy is also a promising direction in the treatment of malignant neoplasms.
 There are obvious prospects for PDT in oncology not as a separate method of treatment, but as part of a complex multimodal treatment, including chemotherapy, radiation therapy, surgical treatment, and immunotherapy.

Photoelectrocatalytic modification of nanofiltration membranes with SrF2/Ti3C2Tx to simultaneously enhance heavy metal ions rejection and permeability

Heavy metal pollution can significantly harm water systems and human health. Combining photoelectrocatalytic (PEC) and nanofiltration (NF) membrane separation technologies can effectively remove heavy metal ions from wastewater. In this study, a water bath method was used to form SrF2/Ti3C2Tx (ST) nanoparticles on the surface of polyvinylidene fluoride (PVDF) membranes and an additional polyamide (PA) functional layer was formed at the interface by crosslinking. ST@PA composite NF membranes (STPP) with good photocatalytic performance were obtained. The separation and catalytic properties of the STPP membranes were controlled by the ST content, which modifies the surface structure and properties of the membranes. The membrane with optimal ST crosslinking exhibited a water contact angle of 50.8°, pure water flux of 24.6 L·m−2·h−1·bar−1, and rejection rates of Mn2+, Ni2+, Cu2+, and Zn2+ of 98.8%, 95.3%, 95.7%, and 97.3%, respectively, under PEC-assisted separation with visible light illumination from a Xe lamp (300 W) and an applied voltage (2 V). The STPP membranes showed improved rejection rates of heavy metal ions under PEC-assisted operation. The mechanism for the improved membrane performance under PEC conditions was preliminarily clarified considering the relationship between the photocatalytic and filtration properties of STPP membranes along with the influence of light irradiation and an external voltage on the heavy metal ions. The generation of electrons, holes, superoxide radicals, and hydroxyl radicals during membrane operation enhances the rejection rates of heavy metal ions. Based on these results, STPP membranes are considered a promising technology for industrial applications in heavy metal removal.

Mechanistic insights for nickel catalyzed light‐assisted carbon–sulfur cross‐coupling reaction

The C–S cross‐coupling reaction is a very efficient and powerful tool for constructing C–S bonds. Despite the well‐reported C–S cross‐coupling protocols using aryl halides, this reaction using sp2‐hybridized nonaromatic halides is still challenging. Herein, we report light‐assisted C–S cross‐coupling between thiols and 5‐chlorobenzofurazan under blue LED irradiation. We used a new nickel catalyst to synthesize 11 unpublished compounds. Furthermore, we assessed the mechanism and the influence of light irradiation on this reaction and proposed a plausible mechanism that is mediated by the excited state of the nickel catalyst promoted by irradiation with blue light and the C–S coupling product formed. Notably, C–S cross‐coupling under light irradiation was performed for the first time using a nickel catalyst in the absence of an external photocatalyst. We demonstrated that because nickel has a low energy barrier for oxidative addition, this protocol proceeded efficiently using chlorine as a leaving group, and the excited state of the nickel catalyst promoted reductive elimination with a lower energy barrier. It is important to mention that the procedure was tolerated by many functional groups within the thiol, affording a greater than 99% yield after reacting for 6 h.

First PEM photoelectrolyser for the simultaneous selective glycerol valorization into value-added chemicals and hydrogen generation

The photoelectrocatalytic (PEC) valorization of glycerol is emerging for the co-generation of hydrogen and value-added organics like glyceraldehyde (GAD) or dihydroxyacetone (DHA). In this work, we have designed, tested and optimized a pioneering photoelectrolyser with a non-noble metal-based photoanode (WO3), operating in near-neutral conditions and using a proton-exchange membrane (PEM) which ensures the elution of a purified hydrogen stream from the cathode side while selectively oxidizing glycerol on the anode. The influence of light irradiation, external bias and cell temperature has been investigated, leading to GAD and DHA production rates of 11.1 and 5.2 mmol m−2 h−1 at 60 ºC and 1.2 V, along with 44.0 mmol H2 m−2 h−1. The long-term stability of the photoelectrolyser has also been validated and the particularities of this system with respect to other conventional devices have been discussed. PEC stands as a promising sustainable technology for the simultaneous H2 generation and biomass valorization.

Magnetic amino-sulfonic dual sorbent for uranyl sorption from aqueous solutions – Influence of light irradiation on sorption properties

The association of magnetite microparticles with bi-functional amino-sulfonate polymer (obtained by condensation of guanidine and amino hydroxynaphthalene sulfonic acid, mediated by formaldehyde) allows synthesizing a magnetic composite sorbent (M−GANS). The sorbent bearing both amine and sulfonate groups is efficient for uranyl sorption at pH 4–5. The sorption isotherms are successfully fitted by the Temkin equation, while kinetics is controlled by the pseudo-first order rate equation. The sorption properties are increased by UV irradiation in terms of both sorption capacity (by 25 %, up to 1.25 mmol U g−1) and kinetics. The sorption occurs on both amine and sulfonate groups; the improvement in sorption properties under UV irradiation is tentatively assigned to the photo-reduction of uranyl species (mediated by magnetite particles and amine groups from polymer layer). The UV irradiation improves the selectivity of M−GANS for uranium against other metal ions, tested on both synthetic and real solutions. This improvement can be correlated to the higher propensity of uranyl to be photo-reduced compared with investigated competitor ions. The recycling of the sorbent was successfully tested for five successive cycles of sorption and desorption (stably complete): the loss in sorption performances is slightly reduced (less than 1.5 % at the fifth cycle) under UV irradiation compared with experiments performed under dark conditions (loss close to 4.2 %). The uranium peroxide precipitate obtained at the end of the treatment of acid leachate of ore shows higher purity when UV irradiation was applied.

Influence of Light Irradiation on Potential-Induced Degradation for Thin-Film Si Photovoltaic Modules

Delamination observed for superstrate-type thin-film Si photovoltaic (PV) modules exposed outdoors was reproduced by indoor acceleration test with high-voltage application. Such delamination was observed for the PV modules left in the air after potential-induced degradation (PID) acceleration test and was a kind of PID. The delamination occurred near the interface between glass and transparent conductive oxide. In this study the origins of the delamination for thin-film Si PV modules were analyzed and the influences of light irradiation and humidity were also investigated. The delamination occurred only at the position with voltage application and high concentration of Na was detected at the delamination region. Delamination was also enhanced by high humidity. It also turned out that light irradiation delays both deterioration of PV performances and also the delamination by high-voltage application. However, PID behaviors are almost the same regardless of including UV component. This is much different from crystalline Si case that UV component is required for the PID delay.

The dark side of white hair? Artificial light irradiation reduces cortisol concentrations in white but not black hairs of cattle and pigs

Analysing hair cortisol concentrations (HCCs) is a minimally invasive way to retrospectively assess long-term stress, and its application in studies of animal welfare and stress has attracted considerable interest. However, not only stress-related effects but also hair-specific characteristics and external influences can affect HCCs and interfere with the interpretation of results. Thus, it was the aim of this study to investigate the impact of daylight and UV irradiation on cortisol concentrations in the hairs of pigs and cattle. We also examined whether a potential irradiation effect on HCCs depended on the colour of the hair. For this purpose, black and white hair samples from 18 Saddleback pigs and 18 Holstein Friesian cattle were exposed to artificial light (both visible and UV) and compared with control hair samples from the same animals kept in the dark. Exposure to artificial light significantly decreased HCCs in both pigs (P < 0.05) and cattle (P < 0.001), and hair colour had an influence on HCCs, with black hair showing higher cortisol levels than white hair (cattle: P < 0.001, pigs: P = 0.07). The interaction between light exposure and hair colour was significant in both pigs (P < 0.01) and cattle (P < 0.001), so light exposure reduced HCCs in porcine white hair but not black hair. In cattle, light-exposed white hair exhibited lower hair cortisol levels than control white hair or black hair. These results demonstrate that artificial light irradiation degrades hair cortisol or favours its elimination by structural changes of the hair matrix. However, this effect was only detectable in white hair, indicating that the melanin pigments in black hair absorbed radiation, thereby reducing the effects of photodegradation. Compared with other known influencing factors on HCCs, such as age and body region, the influence of light irradiation was relatively low in this in vitro experiment. However, further studies should investigate this influence under real-life animal conditions, such as outdoor and indoor housing.

The Influence of Light Irradiation on the Photocatalytic Degradation of Organic Pollutants

The design of a photocatalytic process must consider intrinsic and extrinsic parameters affecting its overall efficiency. This study aims to outline the importance of balancing several factors, such as radiation source, total irradiance, photon flux, catalyst substrate, and pollutant type in order to optimize the photocatalytic efficiency. Titanium oxide was deposed by the doctor blade technique on three substrates (microscopic glass (G), flour-doped tin oxide (FTO), and aluminum (Al)), and the photocatalytic properties of the samples were tested on two pollutants (tartrazine (Tr) and acetamiprid (Apd)). Seven irradiation scenarios were tested using different ratios of UV-A, UV-B + C, and Vis radiations. The results indicated that the presence of a conductive substrate and a suitable ratio of UV-A and Vis radiations could increase the photocatalytic efficiency of the samples. Higher efficiencies were obtained for the sample Ti_FTO (58.3% for Tr and 70.8% for Apd) and the sample Ti_Al (63.8% for Tr and 82.3% for Apd) using a mixture of three UV-A and one Vis sources (13.5 W/m2 and 41.85 μmol/(m2·s)). A kinetic evaluation revealed two different mechanisms of reaction: (a) a one-interval mechanism related to Apd removal by Ti_FTO, Ti_Al (scenarios 1, 4, 5, and 7), and Ti_G samples (scenario 7) and (b) a two-interval mechanism in all other cases.

The influence of ultraviolet radiation on the colour of thermo-mechanically modified beech and oak wood

The study examined the influence of ultraviolet radiation on the colour of thermo-mechanically modified beech (Fagus sylvatica) and oak (Quercus robur). The wood colour parameters were measured using the mathematical CIE L*a*b* and L*C*h colour space models. The higher the temperature of thermo-mechanical treatment, the least susceptible beech and oak wood was to a change in L*, a* and b* under the influence of light irradiation. The greatest changes in the colour of non-densified and densified beech and oak wood occurred after 20 h of light irradiation. The higher the temperature of thermo-mechanical treatment, the smaller were the total changes in the colour of beech and oak wood under the influence of ultraviolet radiation. The total changes in the colour of beech densified at temperatures of 100°C and 150°C that took place under the influence of ultraviolet radiation were twice as high as in the case of densified oak wood. The colour of oak wood modified at a temperature of 200°C did not change significantly in 300 h of light irradiation.

The photocatalytic performance of the ZnO/g-C3N4 composite photocatalyst toward degradation of organic pollutants and its inactivity toward hydrogen evolution: The influence of light irradiation and charge transfer

In the present work, ZnO/g-C3N4 photocatalysts were synthesized via a simple calcination method. The physical properties of the obtained ZnO/g-C3N4 nanocomposites were characterized by various physicochemical techniques. The photocatalytic activity of the photocatalysts was investigated by the degradation of methyl orange (MO) and 4-chlorophenol (4-CP) under visible light irradiation. Especially, the photocatalytic efficiency was the highest when the percentage of ZnO was 10%. However, an increase of the photocatalytic activities was related to the interfacial transfer of photogenerated electrons and holes, leading to the effective charge separation. More importantly, the nanocomposite showed no activity toward hydrogen.

Effects of Different Light Sources on Neural Activity of the Paraventricular Nucleus in the Hypothalamus.

Background and Objectives: Physical function is influenced by light irradiation, and interest in the influence of light irradiation on health is high. Light signals are transmitted from the retina to the suprachiasmatic nucleus (SCN) via the retinal hypothalamic tract as non-image vision. Additionally, the SCN projects a nerve to the paraventricular nucleus (PVN) which acts as a stress center. This study examined the influences of three different light sources on neural activity in the PVN region using two different color temperatures. Materials and Methods: Experiments were conducted using twenty-eight Institute of Cancer Research (ICR) mice (10 week old males). Three light sources were used: (1) organic light-emitting diode (OLED) lighting, (2) LED lighting, and (3) fluorescent lighting. We examined the effects of light irradiation from the three light sources using two different color temperatures (2800 K and 4000 K). Perfusion was done 60 min after light irradiation, and then the brain was removed from the mouse for an immunohistochemistry analysis. c-Fos was immunohistochemically visualized as a marker of neural activity in the PVN region. Results: The number of c-Fos-positive cells was found to be significantly lower under OLED lighting and LED lighting conditions than under fluorescent lighting at a color temperature of 2800 K, and significantly lower under OLED lighting than LED lighting conditions at a color temperature of 4000 K. Conclusions: This study reveals that different light sources and color temperatures alter the neural activity of the PVN region. These results suggest that differences in the light source or color temperature may affect the stress response.

A New Approach for Spontaneous Silver Ions Immobilization onto Casein.

The work presents the kinetic and isotherm studies of silver binding on casein, which was carried out using batch sorption technique. Moreover, the influence of light irradiation on the process was shown. In order to investigate the mechanism of metal ions sorption by casein the zero, pseudo-first order kinetics and Weber-Morris intra-particle diffusion as well as Langmuir and Freundlich isotherm models were used. Furthermore, to specify more precisely, the possible binding mechanism, the spectroscopic (FT-IR—Fourier Transform Infrared Spectroscopy, Raman), spectrometric (MALDI-TOF MS—Matrix-Assisted Laser Desorption/Ionization Time Of Flight Mass Spectrometry), microscopic (SEM—Scanning Electron Microscope, TEM/EDX—Transmission Electron Microscopy/Energy Dispersive X-ray detector) and thermal (TGA—Thermogravimetric Analysis, DTG—Derivative Thermogravimetry) analysis were performed. Kinetic study indicates that silver binding onto casein is a heterogeneous process with two main stages: initial rapid stage related to surface adsorption onto casein with immediate creation of silver nanoparticles and slower second stage of intraglobular diffusion with silver binding in chelated form (metalloproteins) or ion-exchange form. Spectroscopic techniques confirmed the binding process and MALDI-TOF MS analysis show the dominant contribution of the α-casein in the process. Moreover, the treatment of silver-casein complex by artificial physiological fluids was performed.

Biochemical response of indigenous microalgal consortia to variations in nitrogen concentration of treated effluent

Cultivation conditions influence microalgal cellular components, such as lipid accumulation under nutrient depletion, high light irradiation and salinity stress. In this study, indigenous microalgal consortia were cultivated in batch mode using an actual treated effluent. The temporal response of cellular components to the variations in nitrogen concentration and influence of light irradiation on the response were investigated. Prolonged exposure of indigenous microalgal consortia to nitrogen exhaustion had minor effects on total lipid accumulation and enhancement of energy content. Nitrogen replenishment was followed by immediate crude protein accumulation for growth recovery. Total lipid reduction was observed under light and dark conditions after nitrogen replenishment. A one-day lag after nitrogen replenishment in the total lipid reduction was revealed under nitrogen depletion; meanwhile, under nitrogen exhaustion, lipids were utilised as the primary carbon and/or energy source after replenishment, as represented by the decrease from 10.8% to 9.04% within 6 h after the replenishment.

The Effect of Multispectral Light Emitting Diodes (LEDs) on the Activation of Morphogenic Processes in Cell Culture of Rice Oryza Sativa l

The influence of light irradiation with different intensity parameters and different spectral composition on morphogenic structures, namely green zones of cultivar Dolinny cell cultures was investigated. Light irradiation was generated by 10 types of LEDs with different spectra: cold white (Cold W), white (W), warm white (Warm W), Full spectrum, Red, Deep Red, Yellow, Green, Blue and Royal Blue. It was shown that LEDs with Cold W, W and Royal Blue more actively influenced on green zones generation, while Red, Red Deep, Yellow и Green displayed no results. Standard fluorescent lighting illumination (WFL) was used as a control. The number of induced green zones was lower under control luminescent light (WFL) in comparison with the green zones, which were induced by the illumination of the most active spectra of LEDs, but lifetime of these control structures was longer. After 19 weeks of cultivation, degradation of the green zones of the calli was not observed under control and LEDs Cold W, Warm W, and Blue in the position with maximal intensity of light. The Royal Blue illumination displayed the same results not only in the position with maximum intensity but also at the other intensities approaching the control values (49,3 230 μmol/s*m2).

Anoxic oscillating MBR for photosynthetic bacteria harvesting and high salinity wastewater treatment

In this study, photosynthetic bacteria (PSB) were first harvested by MBR with pendulum type oscillation (PTO) hollow fiber module in succession and on a large scale. Based on unique properties of PSB, PSB/MBR was successfully applied for high-salinity wastewater treatment. Compared with control PSB-MBR (CMBR), PSB/PTO-MBR exhibited more excellent organics removal, which was mainly attributed to much higher biomass production for utilization. Meanwhile, the influence of light irradiation and aeration on activity of PSB was investigated in detail. Results showed that PTO-MBR with 12h light irradiation proved to be a promising and economical alternative. The cycle of dark/light and anoxic had a positive effect on PSB cultivating. Moreover, PTO-MBR exhibited much higher flux than CMBR even if large amounts of biomass existed, which demonstrated that the strong shear stress on interface of liquid-membrane played important roles on membrane fouling reduction.

Influence of Light Irradiation Through Zirconia on the Degree of Conversion of Composite Cements.

To assess the light irradiance (LI) delivered by two light-curing units and to measure the degree of conversion (DC) of three composite cements and one flowable composite when cured through zirconia or ceramic-veneered zirconia plates with different thicknesses. Three dual-curing composite cements (Clearfil Esthetic Cement, Panavia F2.0, G-CEM LinkAce) and one light-curing flowable composite (G-aenial Universal Flo) were investigated. Nine different kinds of zirconia plates were prepared from three zirconia grades (YSZ: Aadva and KATANA; Ce-TZP/Al2O3: NANOZR) in three different thicknesses (0.5- and 1.5-mm-thick zirconia, and 0.5-mm-thick zirconia veneered with a 1.0-mm-thick veneering ceramic). Portions of the mixed composite cements and the flowable composite were placed on a light spectrometer to measure LI while being light cured through the zirconia plates for 40 s using two light-curing units (n = 5). After light curing, micro-Raman spectra of the composite films were acquired to determine DC at 5 and 10 min, 1 and 24 h, and at 1 week. The zirconia grade and the thickness of the zirconia/veneered zirconia plates significantly decreased LI. Increased LI did not increase DC. Only the Ce-TZP/Al2O3 (NANOZR) zirconia was too opaque to allow sufficient light transmission and resulted in significantly lower DC. Although zirconia-based restorations attenuate the LI of light-curing units, the composite cements and the flowable composite could be light cured through the YSZ zirconia. LI is too low through Ce-TZP/Al2O3 zirconia, necessitating the use of self-/dual-curing composite cements.

Production of hydrogen from glucose by LaFeO3 based photocatalytic process during water treatment

In this work the hydrogen production from photocatalytic degradation of glucose aqueous solution using LaFeO3 catalysts was investigated under UV or visible light irradiation by light-emitting diodes (LEDs). Different LaFeO3 catalysts were prepared by solution combustion synthesis, starting from lanthanum nitrate and iron nitrate aqueous solution, and different amounts of citric acid as organic fuel. The influence of light irradiation and amount of citric acid was evaluated. The photocatalysts were characterized by different techniques, such as XRD, BET, UV–Vis DRS and Raman spectroscopy. As the amount of citric acid was increased from 0.86 to 2.15 g, the specific surface area of perovskite was increased from 4 to 24 m2/g, with crystallite size of 38 and 6 nm, respectively. Moreover, the different amounts of citric acid induced changes in the crystallinity degree of LaFeO3 perovskite. LaFeO3 catalyst prepared with a double amount of citric acid (1.72 g) compared to the initial content (0.86 g), was the most active in the photocatalytic production of H2 (up to 1.6 mmol/gcat after 4 h of UV irradiation, corresponding to 16% of hydrogen yield). With this photocatalyst the simultaneous degradation of glucose was 73% after 4 h of UV irradiation. These results are encouraging with respect to the possibility to produce hydrogen during photocatalytic treatment of sugar-containing water by using photocatalysts in the absence of noble metals.

Ultrasonic measurement of the effects of light irradiation and presence of water on the polymerization of self-adhesive resin cement.

Self-adhesive resin cements are useful in restorations because they reduce the number of clinical steps involved in the restoration process. This study evaluated, using ultrasonic measurements, the influence of light irradiation and the presence of water on the polymerization behavior and elastic modulus of a self-adhesive resin cement. A self-adhesive resin cement (RelyX Unicem 2 Automix) or a resin cement (RelyX ARC) was inserted into a transparent mold on a sample stage, and the presence of water and effect of light-irradiation were evaluated. The transit time of a sonic wave through the cement disk was divided by the specimen thickness to obtain the sonic velocity, and longitudinal and shear waves were used to determine the elastic modulus. When the resin cements were light-irradiated, the sonic velocity rapidly increased and plateaued at 2,500-2,700ms-1 . When the cements were not irradiated, the rates of increase in the sonic velocity were reduced. When water was applied to the sample stage, the sonic velocity was reduced. The elastic modulus values of the specimens ranged from 9.9 to 15.9GPa after 24h. The polymerization behavior of self-adhesive resin cements is affected by the polymerization mode and the presence of water.