Pigment Grade Research Articles

Clofazimine serum concentration and safety/efficacy in nontuberculous mycobacterial pulmonary disease treatment

BackgroundClofazimine (CFZ) has shown promising effects against Mycobacterium avium-intracellulare complex pulmonary disease (MAC-PD) and Mycobacterium abscessus species pulmonary disease (MABS-PD). However, the optimal CFZ dose remains unknown. We aimed to explore the relationship between steady-state CFZ concentration and its safety and efficacy in MAC-PD and MABS-PD. MethodsThis prospective observational study focused on patients with MAC-PD and MABS-PD treated with CFZ (UMIN 000041053). To understand the safety and efficacy profile of CFZ and elucidate its optimal concentration, we analyzed CFZ-induced pigmentation grade, QTc interval, and culture conversion outcomes in relation to serum CFZ concentration using Student's t-test, a concentration-QTc model, and multivariable logistic regression analysis, respectively. In total, 64 patients (34 with MAC-PD; 30 with MABS-PD) were included. ResultsThe steady-state concentration of CFZ was higher in the moderate-to-severe pigmentation group than in the none-to-light pigmentation group (P < 0.001). At a CFZ concentration of 1 mg/L, the QTc interval was prolonged by 17.3 ms (95 % confidence interval [CI], 3.9–25.4) from baseline. Culture conversion was achieved in 33 (51.6 %) patients. The only significant predictor of culture conversion was surgery (adjusted odds ratio, 5.4; 95 % CI, 1.3–38.0). CFZ concentration and MIC of CFZ less than 0.25 mg/L were not associated with culture conversion in this study. ConclusionCFZ-induced pigmentation and QT interval prolongation are associated with serum CFZ concentrations. CFZ dosage may be optimized by monitoring serum CFZ concentration.

Combination of Fractional Carbon Di Oxide Laser with Narrow Band Ultravoilet B Therapy to induce repigmentation in stable resistant vitiligo- A split-lesional study

Context: Resistant vitiligo is challenging to treat and needs new therapeutic approaches such as combining fractional carbon dioxide (CO2) laser and narrow-band ultraviolet B (NB-UVB) therapy. Aims: The study aimed to determine the efficacy and safety of combining fractional CO2 laser and NB-UVB therapy to induce repigmentation in resistant localized vitiligo patches. Materials and Methods: In this open, prospective, split-lesional study, 40 stable resistant vitiligo patches in 30 patients were included and assessed. After an initial assessment, a few resistant patches of vitiligo were identified, and a symmetrical half of it was given two sessions of fractional CO2 laser 1 month apart, followed by NB-UVB sessions to both sides thrice weekly for 3 months. Photographs were taken at baseline and 12 weeks, and repigmentation responses were assessed by calculating the mean percentage of improvement and mean grade of pigmentation on the fractional CO2 laser with NB-UVB site (test) and the only NB-UVB site (control) and then compared using Wilcoxon signed-rank test, with significance determined by P value &lt;0.05. Results: The mean grade of pigmentation (1.8±0.88) and mean surface area improvement (8.40 ± 6.82 cm2) on the fractional CO2 laser with NB-UVB site (test) were statistically better than the mean grade of pigmentation (1.27 ± 0.71) and mean surface area improvement (5.37 ± 6.76 cm2) on the NB-UVB site. A better grade of pigmentation was noted over sun-protected areas with fractional CO2 and NB-UVB therapy, while NB-UVB therapy fared better in sun-exposed areas. Conclusions: Fractional CO2 laser with NB-UVB therapy is an effective treatment in resistant vitiligo patches, especially for sun-protected areas.

DNA damage in workers exposed to pigment grade titanium dioxide (TiO2) and association with biomarkers of oxidative stress and inflammation

The present study was aimed at investigating DNA damage, micronuclei frequency and meta-nuclear alterations in buccal cells of workers involved in pigment-grade TiO2 production (15 exposed and 20 not-exposed). We also assessed associations of genotoxicity biomarkers with oxidative stress/inflammatory biomarkers in urine and exhaled breath condensate (EBC), as well as possible associations between biomarkers and reported respiratory symptoms. In spite of compliance with TiO2 Occupational Exposure Limits, results showed increased direct/oxidative DNA damage and micronuclei frequency in exposed workers. Genotoxicity parameters were associated with oxidative stress/inflammation biomarkers in urine and EBC, thus confirming that TiO2 exposure can affect the oxidative balance. Workers with higher genotoxic/oxidative stress biomarkers levels reported early respiratory symptoms suggesting that molecular alterations can be predictive of early health dysfunctions. These findings suggest the need to assess early health impairment in health surveillance programs and to address properly safety issues in workplaces where TiO2 is handled.

Role of ripasudil as an adjunct treatment in the management of pseudoexfoliative glaucoma.

Ripasudil is a class of drug which alters the trabecular meshwork to increase the aqueous outflow and has been shown to be effective in pseudoexfoliative glaucoma (PXF G). This study aimed at assessing the efficacy and safety profile of ripasudil as an adjunct treatment in patients with PXF G at maximal tolerated antiglaucoma medications. In this prospective, interventional study, 40 patients with PXF G were enrolled between May 2021 and Jan 2022. Ripasudil 0.4% was started as an adjunctive drug to the ongoing antiglaucoma medications. On follow-up visits at 1, 3, and 6 months, the visual acuity, intraocular pressure (IOP), anterior segment, and fundus findings were evaluated. The premedication and postmedication IOP values were compared by paired t-test, and a P-value <0.05 was considered statistically significant. Average age at recruitment was 60.02 ± 8.74 years. Baseline premedication IOP was 25.375 ± 3.276 mmHg. IOP reduction at 6 months was found to be statistically significant in all patients, with the maximal response being 24.13%. Also, 87.5% (35/40) of patients reached target IOP or even lower IOP at the end of study. There was no statistically significant association between the PXF grade and IOP. However, the grade of inferior iridocorneal angle pigmentation was found to be higher in eyes with elevated IOP (P < 0.05). Only three patients developed conjunctival hyperemia as an adverse reaction, which was mild and transient. Ripasudil showed additional IOP-lowering effect with other antiglaucoma medications and exhibited no significant side effects.

Correlations between capillary density and degree of skin pigmentation in healthy children analysed by nailfold video capillaroscopy.

Nailfold video capillaroscopy (NVC) is a simple, non-invasive diagnostic tool but studies with normal values for capillary density in healthy children are rare. Ethnic background seems to play a role in capillary density; however, this is not well substantiated yet. In this work, we set out to evaluate influence of ethnic background/skin pigmentation and age on capillary density reading in healthy children. Secondary aim was to investigate whether there is a significant difference in density between different fingers within the same patient. Between 2016 and 2021, healthy children from schools around AUMC were approached, by convenience sampling. In this cross-sectional study, capillaroscopic images were obtained in a one-time videocapillaroscopy (×200 magnification) addressing the capillary density (i.e., number of capillaries per linear millimetre in the distal row). This parameter was compared to age, sex, ethnicity, skin pigment grade (I-III) and between eight different fingers, excluding the thumbs. Density differences were compared by ANOVAs. Correlations between capillary density and age were calculated with Pearson correlations. We investigated 145 healthy children with mean age of 11.03 years (SD 3.51). The range of capillary density was 4-11 capillaries per millimetre. We observed a lower capillary density in the 'grade II' (6.4±0.5 cap/mm, P<0.001) and 'grade III' (5.9±0.8 cap/mm, P<0.001) pigmented-classified groups compared to the 'grade I' group (7.0±0.7 cap/mm). We did not find a significant correlation between age and density in the overall group. The fifth fingers on both sides had a significantly lower density compared to the other fingers. Healthy children <18 years with higher degree of skin pigmentation show a significantly lower nailfold capillary density. In subjects with an African/Afro-Caribbean and North-African/Middle-Eastern ethnicity, a significantly lower mean capillary density was observed compared to subjects with the Caucasian ethnicity (P<0.001, and P<0.05, respectively. There were no significant differences between other ethnicities. No correlation was found between age and capillary density. The fifth fingers on both hands displayed lower capillary density compared to the other fingers. This needs to be taken into account when describing lower density in paediatric patients with connective tissue diseases.

Orion & Cabot hike prices for pigment & conductive grades of carbon black

Orion & Cabot hike prices for pigment & conductive grades of carbon black

In-situ analysis of the Al-Fe-Mn-Cu oxide oxygen carrier for chemical looping applications

A novel Al-Fe-Mn-Cu oxide oxygen carrier, termed Gen3, was developed by NETL and prepared using natural ore and pigment grade materials. Gen3 was subjected to 10 cycles of reduction-oxidation (redox) through confocal laser scanning microscopy (CLSM) and thermogravimetric analysis (TGA), separately. TGA results indicated that Gen3 shows promise as an oxygen carrier, repeatably lending approximately 6% of its mass to oxygen carrying capacity. CLSM characterization led to the identification of different swelling behaviors among particles of ‘smooth’ (spinel-S) vs. ‘rough’ (spinel-R) surface morphologies, labeled based on appearance before redox cycling. Spinel-R particles exhibited homogeneous chemistry and porosity. Spinel-S particles showed much more localized porosity, specific to high-Cu areas. Gen3 particle volume increased 60% for spinel-S particles and 30% for spinel-R particles over the course of 10 redox cycles. All conditions showed some degree of separation of the complex Al-Fe-Mn-Cu spinel. Primary observed phases included Al-rich spinel, Fe-rich spinel, and Cu/CuO. Al-rich spinel and Cu/CuO in exposed Gen3 at times formed a lamellar structure of alternating Al-rich and Cu-rich layers in exposed Gen3 near areas rich in Cu. An additional Si-O-K-type phase was also observed that likely arose from the impurities involved in pigment grade materials and natural ores. Segregation increased with level of exposure. Si-rich regions and Fe-rich spinels showed extremely low porosity; a more evenly mixed Al-Fe-Mn-Cu spinel showed moderate porosity; Cu and Cu-rich spinel by far showed the highest porosity.

Process Simulation and Life Cycle Assessment of Ceramic Pigment Production: A Case Study of Green Cr2O3

This study presents a combined process modeling—Life Cycle Assessment (LCA) approach for the evaluation of green Cr2O3 ceramic pigments production. Pigment production is associated with high calcination temperatures, achieved through the combustion of fossil fuels. Therefore, it is necessary to evaluate its environmental impact with regards to energy requirements and CO2 emissions. Initially, a process model is developed to simulate the final calcination stage of the traditional pigments production process. It is validated against titanium dioxide (TiO2) white production industrial data and adjusted for Cr2O3 production. Three alternative processes are examined: two for pigment grade (PIGM1, PIGM2) and one for metallurgical (MET) Cr2O3. Heat demand and CO2 emissions computed by the developed process models are used as input in the LCA along with upstream data from the literature using a cradle-to-gate approach. The implementation of the LCA has resulted in calculated Global Warming Potential (GWP100) ranging from 7.9 to 12.8 CO2-eq and fossil Primary Energy Demand (PED) between 91.4–159.6 MJ-eq (all referring to 1 kg of pigment production). It is depicted that the biggest part of the emissions originates from the upstream production and transportation of raw materials (contributing up to 96% of total CO2 emissions) and other sources (electricity, production plant, etc.), rather than the examined calcination stage (contributing from 1.3 to 3.5% of GWP).

Development of CuFeMnAlO4+δ oxygen carrier with high attrition resistance and 50-kWth methane/air chemical looping combustion tests

A Copper-Ferri-Manganese-Aluminate spinel (CuFeMnAlO4+δ) oxygen carrier, developed at the US Department of Energy’s (DOE) National Energy Technology Laboratory (NETL), shows promising results for chemical looping combustion with methane. Attrition resistance of the spinel oxygen carrier (160–600 µm) produced by a wet agglomeration method was significantly higher than that observed previously with a Copper-Ferri-Aluminate (CuFeAlO4) oxygen carrier. Improved attrition resistance of the novel carrier can be attributed to minimal alumina phase segregation and minimal carbon formation. Heats of reaction measured by differential scanning calorimetry indicated exothermicity during reduction with methane. The total oxygen transfer capacity of the material was about 10.5 wt% at 850 °C. The attrition resistance and the oxygen transfer capacity of the carrier prepared at a commercial manufacturing facility (180 kg) were very similar to observed values during the development phase with the lab scale preparations. The material displays satisfactory methane conversion and significantly high particle durability during a 54 h test campaign conducted in NETL’s 50-kWth chemical looping dual fluid bed reactor unit at temperatures ranging from 700 to 900 °C. Low oxygen carrier make-up cost, due to the use of natural ore and pigment grade raw materials during synthesis and very low attrition rates, exceeded the performance goals determined by systems studies.

Microchemical analysis of Leonardo da Vinci\u2019s lead white paints reveals knowledge and control over pigment scattering properties

Leonardo da Vinci (1452–1519) is a key artistic and scientific figure of the Renaissance. He is renowned for his science of art, taking advantage of his acute observations of nature to achieve striking pictorial results. This study describes the analysis of an exceptional sample from one of Leonardo’s final masterpieces: The Virgin and Child with St. Anne (Musée du Louvre, Paris, France). The sample was analyzed at the microscale by synchrotron-based hyperspectral photoluminescence imaging and high-angular X-ray diffraction. The results demonstrate Leonardo’s use of two subtypes of lead white pigment, thus revealing how he must have possessed a precise knowledge of his materials; carefully selecting them according to the aesthetical results he aimed at achieving in each painting. This work provides insights on how Leonardo obtained these grades of pigment and proposes new clues regarding the optical and/or working properties he may have tried to achieve.

An investigation on optimum grinding system and conditions for steel plant ARP by-product α-Fe2O3 for pigment industry

After some other processes, α-Fe2O3 red powder particles -by-product of regeneration of spent pickling liquor in ARP in iron and steel industry- should be ground up to pigment grade to convert it to a value added product, red iron oxide pigment. In this study, grinding tests on α-Fe2O3 red powder were performed using four different types of laboratory-scale mills, namely the vibrating cup mill, vertical ball mill, planetary ball mill, and fluidized bed jet mill. The particle structure of the α-Fe2O3 was investigated by SEM, while its chemical composition was determined by ICP-OES, density, LOI, humidity, Cl content etc. were determined by laboratory tests. Particle size distribution and surface area value of each ground sample was determined using the laser diffraction method. Targeted particle size distribution ranges could only be achieved with the jet mill. Other mills encountered caking and adhesion problem with α- Fe2O3. It was assessed that the adhesion to the inner walls of the grinding chamber and the caking effect were both caused by the humidity content of the material. The grinding yield of the material was found to increase with increased jet mill grinding air pressure (0.8, 3.2 and 7 bars).

Synthetic rutile derived titanium alloy development utilising the Metalysis Process and field assisted sintering technology

Utilising novel extraction and processing technologies allows for the realisation of an alternative titanium alloy production route, with many benefits over the traditional Kroll-based one. The route proposed has the potential to reduce the cost of titanium and offers the ability to create alloys which are difficult to make conventionally. It combines the Metalysis Process, an electrolytic metal extraction technique, with field assisted sintering technology (FAST), a rapid and effective solid-state sintering technique. The Metalysis Process reduces metal oxide powders directly into metal powders, which can then be consolidated using FAST. Using synthetic rutile (SR) as the feedstock, compared to pigment grade rutile and TiCl4, further reduces the cost of titanium produced via this route. This research investigates the use of this route to create a range of pseudo-binary Ti-Fe alloys, by co-reducing SR with iron (III) oxide (Fe O ). Various techniques were used to analyse the feedstock, reduced alloy powders and consolidated material post-FAST to 23 determine chemistry and microstructure.

Assessment and grading of pigmentation in chronic venous insufficiency.

Chronic venous insufficiency causes skin pigmentation of the leg ranging from small patches of mild dyschromia to extensive areas of severe skin pigmentation. It is thought that the pigmentation is mainly due to haemosiderin or melanin deposition. Erythrodiapedesis which occurs as a result of venular hypertension causes erythrocytes to migrate across the microvascular network into the dermis. We categorized the grading of pigmentation into four grades: +, few spots; ++, pigmentation over gaiter area; +++, pigmentation involving leg and ankle; ++++, heavily pigmented (dark). Skin biopsies were taken from the patient while undergoing surgery; two biopsies were taken from each patient, one from apparently normal skin and other from the site of pigmentation. A total of 45 patients diagnosed as chronic venous insufficiency with pigmentation were included in the study and five patients included in control. The biopsy specimens were sent to pathology department for H&E, Perls stain and IHC for S100. Majority of cases, i.e. 62% of limbs fall under (++) grade of pigmentation, followed by (+) grade of pigmentation in 20%, while (+++) and (++++) constitute 9% of the cases each. Increased melanin deposition was seen in 40 pigmented skin biopsies and 3 normal skin biopsies from the case group, and normal melanin deposition was seen in all the non-varicose controls. We have tried to categorize pigmentation in chronic venous insufficiency into four grades. As the grade of pigmentation increases the per cent of cases with ulceration is increasing. It was observed that presence of melanin deposition irrespective of the grade of pigmentation was distributed more towards the advanced clinical classification (C5 and C6).

Let-down stability and screen printability of inks prepared using non-printing ink grades of carbon black pigment

Purpose This paper aims to analyse the let-down stability of the binder-free dispersion of non-printing ink grades of carbon black and to assess the screen-printability of the finished inks formulated thereof from these pigment dispersions. Design/methodology/approach Binder-free pigment dispersions that were prepared and optimised following a ladder series of experiments (reported in a separate study by the authors) were let-down with three different binders such that inks containing various amounts of a binder were prepared followed by a rheological characterisation immediately after formulation and after four weeks of storage. The screen printability of the inks that displayed considerable stability was assessed, so was the ink film integrity. Findings The pigment dispersions that were considered in the present study were generally found to be stable after let-down with different binders. This was indicated by the fact that the finished inks possessed a shear thinning viscosity profiles, after formulation and after storage, in most of the cases. Furthermore, the screen printability of the inks was also found to be good in terms of registration quality of a selected design. The structure of the ink film deposits on uncoated and binder-coated textile fabrics was also highly integrated and free from discontinuities. Originality/value Carbon blacks with very low volatile matter content and/or high surface area are generally not considered suitable for use in the formulation of printing inks. This is because of their generally poor dispersability and inability to form dispersions that remain stable over extended periods. This work, which is a part of a larger study by the authors, concerns with the stability of inks formulated from binder-free dispersions of such non-printing ink grades of carbon black. The major advantage of using such pigments in inks is that the required functionality is achieved at considerably low pigment loadings.

A sustainable process for recovery of potash fertilizer from glauconite through simultaneous production of pigment grade red oxide

A sustainable process is proposed and developed for the recovery of potash fertilizer from glauconitic clay with simultaneous production of pigment grade iron oxide. Potassium is a part of stable structure (dioctahedral T-O-T) in glauconite and locked in alumino-silicate matrix. In order to break this matrix and maximize potassium dissolution, the glauconite sample containing 5.6% K2O and 31.9% Fe2O3 was subjected to reduction with coke followed by oxidation cooling (redox roasting). The process simultaneously releases potash and convert iron in the matrix to ferric state. The redox roasted sample was leached in hydrochloric acid and the leach liquor containing 6.1 g/L of potassium and 30.2 g/L of iron was subjected to solvent extraction using mixed solvent system (20% Aliquat 336 and 15% TBP) to separate iron prior to recovery of potash. Based on McCabe–Thiele plot, two stage counter current extraction at O:A ratio of 1:0.75 and three stage stripping at O:A ratio of 0.4:1 are sufficient to remove >99% of iron from the leach solution. The strip solution was hydrothermally treated to produce red iron oxide suitable for pigment application and iron free raffinate was treated to produce fertilizer grade potassium chloride.

Automated anterior chamber angle pigmentation analyses using 360° gonioscopy

PurposeTo assess the pigmentation distribution in the iridocorneal angle using an established algorithm with gonioscopically obtained images.MethodsManual and automatically modified Scheie’s pigmentation grading (ie, 0/I=0, II=1 and III/IV=2) of trabecular...

High electrical conductivity waterborne inks for textile printing

Printing of conductive inks is an attractive means of manufacturing of electronic components on flexible substrates including textiles. The textiles thus produced are often referred to as “e-textiles.” When high electrical conductivity is required, inks are preferably made from metal nanoparticles such as silver. However, such inks are expensive and generally not known to withstand severe washing and wearing to which textiles are normally subjected during the end use. In the present study, which forms a part of a larger study by the authors, waterborne dispersions of conductive grades of carbon black were converted into finished inks followed by washing and creasing tests to ascertain the durability of these inks. We found that not only were the inks stable after letdown with different binders, but they possessed high electrical conductivity despite the fact that the final pigment loading in all of the formulated inks was significantly less than the pigment loading that is generally found in commercial conductive inks. In addition, the electrical conductivity after washing and creasing tests of the formulated inks was found to be significantly greater than that of the tested commercial conductive inks. This shows that using large surface area, highly conductive grades of carbon black pigments in relatively small amounts in inks for textile printing is beneficial in achieving some of the critically required characteristics, particularly those pertaining to durability of the ink film.

High electrical conductivity waterborne dispersions of carbon black pigment

The carbon black grades that are employed as pigments in printing inks are characterised by low surface area, low structure and a higher proportion of chemisorbed polar groups on the surface. All of these features render the pigment easily dispersable – a property crucially important in the case of printing inks. However, high electrical conductivity of carbon black is known to be possessed only by the grades that have high surface area, high structure and lower proportion of polar groups, and consequently poor dispersability. The study reported here aimed to resolve such a dilemma between high electrical conductivity and poor dispersability. Thus, novel methodologies were developed to prepare waterborne, binder-free dispersions based on “non-printing ink” grades of carbon black. The particle size analysis, rheological characterisation, sedimentation analyses and electrical characterisation results clearly indicate that the selected pigment grades of carbon black were successfully stabilised as dispersions that possess high electrical conductivity at considerably lower pigment loadings than normal.

Contemporary methods of production and application of pigments obtained from titanium dioxide

The current article describes the methods of producing titanium dioxide, or titania, which is used in various branches of the industry, including construction as a basis for producing white pigments. The base pigment grades of titania with their qualitative characteristics are listed, the modifying agents, applied in producing pigment grades, are presented, the several technologies of producing titania are mentioned. To obtain titania with different characteristics, various methods of treatment, viz. chemical or heat treatment, are used. To raise the material index of raw materials, used for producing titania and, simultaneously, to lower the obtaining of waste materials, several methods of obtaining titania from titanium slags and waste catalysts are offered. When applying the offered technologies, the range of the usage of titania will be expanded, and the efficiency of using raw materials will be increased.

Synthesis and Characterization of Pigment Grade Red Iron Oxide from Mill Scale

Synthesis and Characterization of Pigment Grade Red Iron Oxide from Mill Scale