Therapeutic Effects of Aloe saponaria against Ulcerative Colitis Induced by Dextran Sulfate Sodium.

Aloe vera (A. vera) has been studied as a treatment option for ulcerative colitis (UC), but there is a lack of scientific evidence showing whether treatment with Aloe saponaria (A. saponaria) can also be beneficial. To investigate the therapeutic potential of A. saponaria as a treatment for UC, clinical symptoms, histopathological characteristics of the colon, inflammatory response, and toxicity were analyzed in dextran sulfate sodium (DSS)-induced UC mice after administration of aqueous extracts of A. saponaria (AAS) for 7 days. The total polyphenol and tannin content of AAS was 272 µg/g and 163 µg/g, respectively. AAS exhibited significant antioxidant activity. Several clinical symptoms, including body weight, colon length, and hematochezia, remarkably improved in the DSS+AAS treated group compared to the DSS+Vehicle-treated group. In addition, similar improvements were detected in the histopathological characteristics and mucin-secreting ability in the colon of DSS-induced UC mice after the administration of AAS. The levels of infiltrated inflammatory cells and cytokine expression were significantly decreased in a dose-dependent manner in the colon of the DSS+AAS-treated group. These alterations in inflammatory response were accompanied by a significant recovery of the protein kinase C/extracellular signal-regulated kinase (PKC/ERK) and phosphatidylinositol-3-kinase/serine-threonine protein kinase (PI3K/Akt) signaling pathways. However, the levels of key markers for hepatotoxicity and nephrotoxicity consistently remained between those of the DSS+AAS-treated and the No groups. Therefore, the results of the present study provide novel evidence that AAS may improve the clinical symptoms and attenuate the inflammatory response in DSS-induced UC mice and does not have any significant hepatotoxicity or nephrotoxicity.

Heat Treatment Enhances the Neuroprotective Effects of Crude Ginseng Saponin by Increasing Minor Ginsenosides.

Ginsenoside is the primary active substance of ginseng and has many pharmacological effects, such as anti-cancer, immune, regulating sugar and lipid metabolism, and antioxidant effects. It also protects the nervous and cardiovascular systems. This study analyzes the effects of thermal processing on the bioactivities of crude ginseng saponin. Heat treatment increased the contents of minor ginsenosides in crude saponins, such as Rg3, and heat-treated crude ginseng saponin (HGS) had better neuroprotective effects than non-treated crude saponin (NGS). HGS reduced glutamate-induced apoptosis and reactive oxygen species generation in pheochromocytoma 12 (PC12) cells, significantly more than NGS. HGS protected PC12 cells against glutamate-induced oxidative stress by upregulating Nrf2-mediated antioxidant signaling and downregulating MAPK-mediated apoptotic signaling. HGS has the potential for the prevention and treatment of neurodegenerative disorders, such as Alzheimer's and Parkinson's disease.

Seasonal Dynamics of Methanotrophic Bacteria in a Boreal Oil Sands End Pit Lake.

Base Mine Lake (BML) is the first full-scale demonstration end pit lake for the oil sands mining industry in Canada. We examined aerobic methanotrophic bacteria over all seasons for 5 years in this dimictic lake. Methanotrophs comprised up to 58% of all bacterial reads in 16S rRNA gene amplicon sequencing analyses (median 2.8%), and up to 2.7 × 104 cells mL-1 of water (median 0.5 × 103) based on qPCR of pmoA genes. Methanotrophic activity and populations in the lake water were highest during fall turnover and remained high through the winter ice-covered period into spring turnover. They declined during summer stratification, especially in the epilimnion. Three methanotroph genera (Methylobacter, Methylovulum, and Methyloparacoccus) cycled seasonally, based on both relative and absolute abundance measurements. Methylobacter and Methylovulum populations peaked in winter/spring, when methane oxidation activity was psychrophilic. Methyloparacoccus populations increased in the water column through summer and fall, when methane oxidation was mesophilic, and also predominated in the underlying tailings sediment. Other, less abundant genera grew primarily during summer, possibly due to distinct CH4/O2 microniches created during thermal stratification. These data are consistent with temporal and spatial niche differentiation based on temperature, CH4 and O2. This pit lake displays methane cycling and methanotroph population dynamics similar to natural boreal lakes. IMPORTANCE The study examined methanotrophic bacteria in an industrial end pit lake, combining molecular DNA methods (both quantitative and descriptive) with biogeochemical measurements. The lake was sampled over 5 years, in all four seasons, as often as weekly, and included sub-ice samples. The resulting multiseason and multiyear data set is unique in its size and intensity, and allowed us to document clear and consistent seasonal patterns of growth and decline of three methanotroph genera (Methylobacter, Methylovulum, and Methyloparacoccus). Laboratory experiments suggested that one major control of this succession was niche partitioning based on temperature. The study helps to understand microbial dynamics in engineered end pit lakes, but we propose that the dynamics are typical of boreal stratified lakes and widely applicable in microbial ecology and limnology. Methane-oxidizing bacteria are important model organisms in microbial ecology and have implications for global climate change.

Effects of laughter therapy on the stress response of married immigrant women in South Korea: A randomized controlled trial.

The authors aimed to investigate the effects of a laughter therapy (LT) program on the acculturative stress, anxiety, depression, salivary cortisol, and salivary IgA of married immigrant women in South Korea. A randomized waiting-list control design was utilized. The 19 experimental group participants were given LT twice a week for 2 weeks, whereas the 22 participants in the waiting-list control group received no treatment during the same period but received it afterward. Outcomes were measured right after the completion of the intervention and 2 weeks later. The experimental group showed significantly decreased levels of acculturative stress, anxiety, depression, and salivary cortisol compared to the control group. As for salivary IgA, however, the experimental group showed no statistically significant decrease compared to the control group. An LT program can be a good option for married immigrant women undergoing acculturation experiences in consideration of its effectiveness.

Effect of silica-containing glass-ceramic liner treatment on zirconia coping retention.

STATEMENT OF PROBLEM: Zirconia prostheses show a high rate of retention loss, and more information is needed regarding the treatment of the intaglios of zirconia prostheses to improve the bond strength between zirconia and resin cement. PURPOSE: The purpose of this in vitro study was to evaluate the retention of titanium abutments and zirconia prostheses treated with silica-containing glass-ceramic liners. The effect of the abutment convergence angle on retention force was also examined. MATERIAL AND METHODS: Titanium abutments and zirconia copings (n=90) were fabricated with 3 different convergence angles (6, 12, and 24 degrees). Specimens were divided into 2 groups according to surface treatment: an airborne-particle-abraded control group and a group that was coated with a silica-containing glass-ceramic liner after airborne-particle abrasion (liner group). The thickness of the liner was measured, and the inner spacing of the zirconia coping was modified in the liner group. The coping was cemented, and the retention was evaluated with a tensile bond strength test by using a universal testing machine. Retention was analyzed by using a 2-way analysis of variance. Modes of failure were evaluated by examining the fracture surface. Elemental analysis of the interface was also performed. RESULTS: The liner group showed a significantly higher retention force for the zirconia prosthesis (P<.05). Regardless of surface treatment, the retention force at a convergence angle of 6 degrees was higher than that at 24 degrees (P<.05). The control group showed mostly adhesive type failures, whereas the liner group exhibited mostly mixed type failures. CONCLUSIONS: Silica-containing glass-ceramic liner treatment increased the retention compared with airborne-particle abrasion treatment alone. Tensile bond strength increased with decreasing abutment convergence angle.

Chemical constituents of Hericium erinaceum associated with the inhibitory activity against cellular senescence in human umbilical vascular endothelial cells.

Hericium erinaceum is an edible and medicinal mushroom widely used in Korea, Japan, and China. On the search for biologically active compounds supporting the medicinal usage, the MeOH extract of the fruiting bodies of H. erinaceum was investigated for its chemical constituents. Six compounds were isolated and identified as hericenone D (1), (22E,24R)-5α,8α-epidioxyergosta-6,22-dien-3ß-ol (2), erinacerin B (3), hericenone E (4), hericenone F (5) and isohericerin (6) by comparing their spectroscopic data with previously reported values. The inhibitory effects on adriamycin-induced cellular senescence in human dermal fibroblasts (HDFs) and human umbilical vein endothelial cells (HUVECs) of the isolates (1-6) were studied. Among the isolated compounds, ergosterol peroxide (2) reduced senescence associated ß-galactosidase (SA-ß-gal) activity increased in HUVECs treated with adriamycin. According to experimental data obtained, the active compound may inspire the development of a new pharmacologically useful substance to be used in the treatment and prevention of age-related diseases.

Comparison between Tonopachy and other tonometric and pachymetric devices.

PURPOSE: This study aimed to compare central corneal thickness (CCT) measurement by Tonopachy to that by Pentacam and ultrasound pachymetry, and intraocular pressure (IOP) measurement to that by Goldmann applanation tonometry (GAT). The reproducibility of CCT and IOP measurements by Tonopachy was also evaluated. METHODS: In 104 eyes of 104 patients, CCT was measured by Tonopachy, Pentacam, and ultrasound pachymetry, and IOP was measured by Tonopachy and GAT. Each CCT and IOP measurement was compared using Pearson correlation, repeated measures analysis of variance, and Bland-Altman plots. In 30 subjects, CCT and IOP measurements by Tonopachy were repeated to evaluate intrasession and intraobserver variability. RESULTS: Both CCT and IOP measurements were highly correlated among all instruments used in this study. CCT measurements by three pachymeters were statistically different (p<0.0001). CCT measured by ultrasound pachymetry was lowest (541.7 ± 30.6 µm) whereas those by Tonopachy and Pentacam showed no difference (557.3 ± 34.3 and 558.0 ± 33.7 µm, respectively). Tonopachy overestimated CCT by 13.9 µm when compared with ultrasound pachymetry. There was a statistically significant difference between IOP measurements by two tonometers (p<0.0001); IOP measurement was higher by Tonopachy than by GAT (13.9 ± 4.2 and 12.5 ± 3.2 mm Hg, respectively). Tonopachy overestimated IOP measurements by 1.2 mm Hg compared with GAT. Intersession agreements for IOP and CCT measurements by Tonopachy were excellent (intraclass correlation, 0.902 and 0.962, respectively) with 95% limits of agreement ranging from -1.4 to 2.2 mm Hg and from -12.9 to 12.1 µm, respectively. CONCLUSIONS: Although CCT and IOP measurements obtained by Tonopachy were reproducible and showed close agreement with ultrasound pachymetry and Pentacam, and GAT, careful attention should be paid when comparing Tonopachy CCT measurement to ultrasound pachymetry or its IOP measurement to GAT as the values may not be interchangeable. Tonopachy is a reliable instrument for evaluating CCT and IOP.

Comparisons of nerve fiber layer thickness measurements between Stratus, Cirrus, and RTVue OCTs in healthy and glaucomatous eyes.

PURPOSE: To compare retinal nerve fiber layer (RNFL) measurements obtained by two spectral-domain optical coherence tomographies (SD OCTs; Cirrus-HD OCT and RTVue) and a time domain OCT (TD OCT; Stratus OCT). The diagnostic ability of the three instruments for glaucoma has also been compared. METHODS: One hundred eight open-angle glaucoma patients and 46 normal controls were enrolled. Three OCT scans were repeated to obtain peripapillary RNFL thickness measurements from all participants on the same day. The relationships between RNFL measurements from three OCTs were evaluated with regression analyses. RESULTS: The thickest RNFL measurements were generally obtained with the RTVue, followed by the Stratus, and finally by the Cirrus OCT (mixed model, p < 0.05). However, the tendency was reversed or no longer present in severe glaucomatous eyes and nasal quadrant maps. Regression analysis between the TD OCT and the two SD OCTs revealed a quadratic relation (linear vs. non-linear, Akaike information criterion, all p < 0.05), whereby RNFL measurements of the TD OCT became exponentially thinner than those by the SD OCTs in thin RNFL thicknesses. Comparing the two SD OCTs, RTVue measured thicker values consistently regardless of the RNFL thickness (pairwise comparisons, p < 0.05). There were no significant differences in the diagnostic ability of all three instruments in average and each quadrants of RNFL thickness (p > 0.05). CONCLUSIONS: Direct comparisons of RNFL thickness measurements among OCT instruments may be misleading as there are considerable differences among devices. The measurement differences between SD OCT and TD OCT differed according to the RNFL thickness and also possibly to severity of the glaucoma. The diagnostic ability of each instrument for glaucoma detection was not significantly different.

Efficacy of brimonidine tartrate 0.2% ophthalmic solution in reducing halos after laser in situ keratomileusis.

PURPOSE: To quantitatively evaluate the effect of brimonidine tartrate 0.2% (Alphagan) on halo and pupil size in patients who had symptomatic night-vision difficulties after laser in situ keratomileusis (LASIK). SETTING: Nune Eye Hospital, Seoul, Korea. METHODS: This study comprised 28 eyes of 14 patients with symptomatic night-vision difficulties after LASIK. Pupil diameter was measured with a Colvard pupillometer (Oasis Medical, Inc.). Quantitative analysis of halos was performed by measuring the area using a new computerized method. Pupil size and halo size were evaluated under scotopic and normal room light conditions. Alphagan was administered, and the effect was measured after 30 minutes and 1, 6, 12, and 24 hours. RESULTS: There was a statistically significant correlation between pupil size and halo size (r = 0.527; P<.0001; slope = 691.6 pixel/mm). Pupil size and halo size decreased significantly 30 minutes after Alphagan instillation under both luminance conditions (all P< .0001). Under normal room light, the pupil and halo remained decreased until the last measurement at 24 hours. Under scotopic conditions, the pupil returned to its preinstillation size at 24 hours while the halo remained decreased. The maximum effect on halos was observed after 6 hours, when the mean reduction over preinstillation size was 28.2% and 29.1% under normal room light conditions and scotopic conditions, respectively. CONCLUSION: Alphagan effectively reduced halo size and pupil size in postoperative LASIK patients with night-vision symptoms.

Central corneal thickness of Korean patients with glaucoma.

OBJECTIVE: To characterize the central corneal thickness (CCT) in Koreans and assess CCT variation in different types of glaucoma. DESIGN: Observational cross-sectional study. PARTICIPANTS: Patients previously diagnosed as primary open-angle glaucoma (POAG, n = 343), normal-tension glaucoma (NTG, n = 192), and ocular hypertension (OHT, n = 44), as well as nonglaucomatous patients (n = 224) examined in a glaucoma clinic in Korea. METHODS: Participants' CCT was measured by ultrasound pachymetry. MAIN OUTCOME MEASURES: Mean CCT and its correlations with glaucoma diagnosis, age, spherical equivalent, gender, diabetes, and hypertension. RESULTS: Mean CCT was highest in eyes with OHT (582.1 microm, P<0.0001), lowest in NTG (537.5 microm, P<0.0001), and intermediate and similar in eyes with POAG and healthy eyes (550.7 and 553.6 microm, respectively, P = 0.289). Central corneal thickness was inversely correlated with age (r = -0.12; P<0.0001). There was no statistically significant difference in mean CCT between eyes with different gender or presence of diabetes and hypertension. Mean CCT in normal and OHT eyes was weakly correlated with refractive error (P<0.05). CONCLUSIONS: In Korean subjects, CCT is greatest in eyes with OHT and least in eyes with NTG.

A study on detection of glucose concentration using changes in color coordinates.

Glucose concentration is closely related to the metabolic activity of cells and it is the most important substance as the energy source of a living body which plays an important role in the human body. This paper proposes an optical method that can measure the concentration of glucose. The change in glucose concentration was observed by using CIE diagram, and wavelength and purity values were detected. Also, even small changes in glucose concentration can be evaluated through mathematical modeling. This system is simple, economical, and capable of quantifying optical signals with numerical values for glucose sensing. This method can be applicable to the clinical field that examines diabetes mellitus or metabolic syndrome.

Impact of short-term exposure of commercial eyedrops preserved with benzalkonium chloride on precorneal mucin.

PURPOSE: The aim of this study is to investigate the short-term effects of benzalkonium chloride (BAC), a preservative used in many ophthalmic topical solutions, on precorneal mucin in humans. METHODS: Immortalized human corneal-limbal epithelial (HCLE) cells were exposed to eyedrops containing BAC solutions at 0.0025% and 0.01% concentrations for a period of 15 min. Human corneal epithelium was acquired with consent, as a byproduct of elective excimer photorefractive keratectomy procedures after application of Ocuflox eyedrops (0.3% ofloxacin with 0.0025% BAC) for 1 week before surgery. The relative expression of the MUC1 and MUC16 mucin gene was determined by conventional and real-time reverse transcription-polymerase chain reaction (RT-PCR). Monoclonal antibodies for MUC1 (HMFG-1) and MUC16 (OC125) were used in western blot analysis to detect MUC1 and MUC16. Human corneas exposed to 0.01% BAC solutions were examined by transmission electron microscopy. RESULTS: The expression of MUC1 and MUC16 gene transcripts was not changed after exposure to BAC in HCLE cells and human corneal epithelium. However, MUC1 and MUC16 were reduced after exposure to BAC in HCLE cells and human corneal epithelium. Transmission electron microscopy of the anterior corneal surface revealed fixation of the mucous layer after exposure to 0.01% BAC for 5 or 15 min; prolonged exposure (60 min) to 0.01% BAC destroys the mucous layer. CONCLUSIONS: This study demonstrates that short-term exposure to BAC can alter the precorneal mucin.

Amniotic membrane as a biologic pressure patch for treating epithelial ingrowth under a damaged laser in situ keratomileusis flap.

We present 2 patients who had epithelial ingrowth after intraoperative laser in situ keratomileusis (LASIK) complications that created defects in the flap near the visual axis. As an adjuvant to removing the epithelium, an amniotic membrane patch was sutured tightly to the episclera so that it covered the entire cornea. The amniotic membrane overlay was left in place for about 1 week. There was no evidence of recurrent epithelial ingrowth after a minimum of 4 months. Use of an amniotic membrane overlay can be an effective adjuvant therapy to secure a LASIK flap when direct suturing would threaten the visual axis.

ESP-102, a Combined Herbal Extract of Angelica gigas, Saururus chinensis, and Schisandra chinensis, Changes Synaptic Plasticity and Attenuates Scopolamine-Induced Memory Impairment in Rat Hippocampus Tissue.

ESP-102, an extract from Angelica gigas, Saururus chinensis, and Schisandra chinensis, has been used as herbal medicine and dietary supplement in Korea. Despite the numerous bioactivities in vitro and in vivo studies, its effects on neuronal networks remain elusive. To address the neuronal effect, we examined synaptic plasticity in organotypic hippocampal slice culture with multielectrode array. Our results showed an increase in excitatory postsynaptic potential (EPSP), indicating the induction of long-term potentiation (LTP), in the presence of ESP-102. In addition, the neuroprotective effect of ESP-102 was also tested by application of scopolamine to the hippocampal slice. Interestingly, ESP-102 competitively antagonized the preventative LTP effect induced by scopolamine. The scopolamine-induced reduction in brain-derived neurotrophic factor (BDNF) and GluR-2 expression was also rescued by ESP-102. In terms of mode of action, ESP-102 appears to act on the presynaptic region independent of AMPA/NMDA receptors. Based on these findings, ESP-102 can be suggested as a novel herbal ingredient with memory enhancing as well as neuroprotective effects.

Responses of human sensory characteristics to 532 nm pulse laser stimuli.

BACKGROUND: Lasers are advantageous in some applications to stimulate a small target area and is used in various fields such as optogenetic, photoimmunological and neurophysiological studies. OBJECTIVE: This study aims to implement a non-contact sense of touch without damaging biological tissues using laser. METHODS: Various laser parameters were utilized in safety range to induce a sense of touch and investigate the human responses. With heat distribution simulation, the amount of changes in the temperature and the tendency in laser parameters of sensory stimulation were analyzed. RESULTS: The results showed the identified tactile responses in safety range with various laser parameters and temperature distribution for the laser stimulus was obtained through the simulation. CONCLUSIONS: This study can be applied to the areas of sensory receptor stimulation, neurophysiology and clinical medicine.

Effect of postoperative refractive error on visual acuity and patient satisfaction after implantation of the Array multifocal intraocular lens.

PURPOSE: To determine the ideal target refraction to optimize visual acuity (VA) and patient satisfaction after implantation of Array SA40N multifocal intraocular lens (IOL) (AMO). SETTING: Inha University College of Medicine, Incheon, Korea. METHODS: The study prospectively enrolled 188 eyes of 163 patients and assigned them to 1 of 3 groups according to their postoperative refractive status: Group 1 (43 myopic eyes, -0.50 diopter [D] to -1.50 D), Group 2 (114 emmetropic eyes, -0.50 D to +0.50 D) and Group 3 (31 hyperopic eyes, +0.50 D to +1.50 D). Uncorrected distance visual acuity (UCDVA), uncorrected near visual acuity (UCNVA), UCDVA under glare conditions, contrast sensitivity, and patient satisfaction were then compared between the 3 groups. RESULTS: Three months postoperatively, UCDVA, UCNVA, UCDVA under glare conditions, and contrast sensitivity were good in all eyes and more than 72% of patients never wore glasses for near vision. In Group 2, UCDVA was significantly better (0.74 +/- 0.20; P<.05) compared with Groups 1 and 3 (0.40 +/- 0.24 and 0.38 +/- 0.30, respectively); UCNVA was also significantly better in Group 2 (0.68 +/- 0.08; P<.05) than in Groups 1 and 3 (0.45 +/- 0.21 and 0.41 +/- 0.17, respectively). However, there were no significant differences in patient satisfaction, contrast sensitivity, and UCDVA under glare conditions between the 3 groups (P>.05). CONCLUSIONS: Aiming for emmetropia rather than myopia when calculating the power for the multifocal intraocular lens may improve visual acuity. However, patients must be considered on an individual basis to meet their expectations and requirements.

Clinical manifestation and pathologic finding of unilateral acute hydrops after bilateral laser in situ keratomileusis.

We present a case of unilateral acute hydrops that developed in 25-year-old man 6 years after bilateral laser in situ keratomileusis (LASIK) for the correction of 2.75 diopters (D) of myopia. Preoperative corneal thickness using ultrasound pachymetry were 556 microm in the right eye and 554 microm in the left eye. Preoperative corneal topography of both eyes showed an asymmetric bow-tie pattern with inferior steepening. Forty-seven months after LASIK, the left eye developed astigmatism and enhancement excimer ablation was performed. Sixteen months after enhancement, a definite sign of keratectasia was detected in the left eye. Twenty-six months after enhancement, acute hydrops occurred in the left eye. The interface of the LASIK wound was separated and filled with aqueous humor. Penetrating keratoplasty was performed to avoid perforation. The keratocytes at the edge between the peripheral flap and remaining stroma showed mixoid degeneration and edematous change suggesting dying cells.

Identifying Organizational Identification as a Basis for Attitudes and Behaviors: A Meta-Analytic Review.

Organizational identification has been argued to have a unique value in explaining individual attitudes and behaviors in organizations, as it involves the essential definition of entities (i.e., individual and organizational identities). This review seeks meta-analytic evidence of the argument by examining how this identity-relevant construct functions in the nexus of attitudinal/behavioral constructs. The findings show that, first, organizational identification is significantly associated with key attitudes (job involvement, job satisfaction, and affective organizational commitment) and behaviors (in-role performance and extra-role performance) in organizations. Second, in the classic psychological model of attitude-behavior relations (Fishbein & Ajzen, 1975), organizational identification is positioned as a basis from which general sets of those attitudes and behaviors are engendered; organizational identification has a direct effect on general behavior above and beyond the effect of general attitude. Third, the effects of organizational identification are moderated by national culture, a higher-level social context wherein the organization is embedded, such that the effects are stronger in a collectivistic culture than in an individualistic culture. Theoretical and practical implications of the findings and future research directions are discussed.

Study of somesthesis according to change in pulse diode laser parameters.

Laser can precisely deliver quantitative energy to a desired region in a non-contact way. Since it can stimulate regions and minutely control parameters such as the intensity, duration and frequency of stimulus, laser is often used for the areas such as low power laser treatment and clinical physiology. This study proposes simulation using pulse diode laser with reliable output and identifies laser parameters that can present a variety of somesthesis. It is found that typically, as frequency and energy increase, the ratio of feeling senses increases, and dominant sense moves from the sense of heat through tactile sense to pain. This study will be baseline data for studies of the sense of heat, tactile sense and pain, contribute to studying neurophysiology sector and be applied to basic clinical research.

Simple LED spectrophotometer for analysis of color information.

A spectrophotometer is the basic measuring equipment essential to most research activity fields requiring samples to be measured, such as physics, biotechnology and food engineering. This paper proposes a system that is able to detect sample concentration and color information by using LED and color sensor. Purity and wavelength information can be detected by CIE diagram, and the concentration can be estimated with purity information. This method is more economical and efficient than existing spectrophotometry, and can also be used by ordinary persons. This contribution is applicable to a number of fields because it can be used as a colorimeter to detect the wavelength and purity of samples.