Crystallinity Research Articles

Influence of Calcination Temperature on the Physicochemical Properties of Synthesized Hydroxyapatite from Cow Bone Waste

The chemical similarity found in hydroxyapatite (HA) with natural bone makes it a popular choice for bone replacement. Therefore, in recent years, there has been an increasing tendency towards manufacturing HA from biological sources or waste, such as animal bone waste. Using naturally derived HA can benefit the economy, the environment, and human health. Therefore, this paper reports on the extraction of HA from cow bone waste using a simple and cost-effective technique. The bone powder was calcined in a furnace at temperatures ranging from 700°C to 1000°C for two hours. Then, the synthesized HA was characterized using a Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-ray Spectroscopy (EDX), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray diffraction (XRD). FESEM images revealed that HA particles with non-uniform spherical morphology were produced where the size increases with the calcination temperature. This finding is consistent with the average value of particle diameter measured at a temperature of 1000°C (0.783±0.268 µm) which is much greater than at a temperature of 700°C (0.272±0.128 µm). EDX analysis revealed that the Ca/P ratio value obtained in this study indicates non-stoichiometric HA production. XRD analysis shows that only the HA phase is present and there is no secondary phase generated from the calcination process. Meanwhile, FTIR analysis can detect the main group elements of the HA which were OH- and PO43-. The findings obtained in this study prove the effectiveness of this method in producing highly crystalline HA powder from cow bone waste using the thermal treatment method.

High-pressure behavior of high-entropy A2B2O7 pyrochlore

A single high-entropy pyrochlore-type compound (A2B2O7) was successfully synthesized, incorporating 8 different rare-earth cations at the A site and 2 different metal cations at the B site in equiatomic amounts [(8A1/8)2(2B1/2)2O7]. Powders with a nominal composition of (La1/8Sm1/8Nd1/8Pr1/8Y1/8Gd1/8Dy1/8Yb1/8)2(Hf1/2Zr1/2)2O7 were fabricated by glycine nitrate procedure (GNP). The GNP process yielded powders with low crystallinity and after subsequent calcination, a well crystalline ceramic powders were formed. The phase evolution was initially analyzed using X-ray diffraction (XRD). In situ high-pressure X-ray diffraction was employed to investigate the structural stability and high-pressure behavior of the A2B2O7 pyrochlore up to 25.8 GPa. Theoretical investigations of the high-entropy pyrochlore systems were performed and showed good agreement with the experimentally obtained results.

Development of inhaled moxifloxacin-metformin formulation as an alternative for pulmonary tuberculosis treatment

Resistant M. tuberculosis strains threaten pulmonary tuberculosis (P-TB) control since they limit drug options. Drug repositioning and new development strategies are urgently required to overcome resistance. Studies have already shown the beneficial role of the oral antidiabetic metformin as an anti-tuberculosis adjuvant drug. This work aimed to develop an inhalatory dry powder co-formulation of metformin and moxifloxacin to figure out a future option for P-TB treatment. Pre-formulation evaluations indicated the physicochemical compatibility of constituents, demonstrating powder crystallinity and acceptable drug content. Eight moxifloxacin-metformin dry powder formulations were produced by spray drying, and solid-state characterizations showed partial amorphization, ascribed to moxifloxacin. Four formulations containing L-leucine exhibited micromeritic and in vitro deposition profiles indicating pulmonary delivery suitability, like spherical and corrugated particle surface, geometric diameters < 5 μm, high emitted doses (>85 %), and mass median aerodynamic diameters between 1–5 μm. The use of a second spray dryer model further optimized the aerodynamic properties and yield of the best formulation, demonstrating the influence of the equipment used on the product obtained. Moreover, the final formulation showed high in vitro cell tolerability and characteristics in permeability studies indicative of good drug retention in the lungs.

Towards end-to-end structure determination from x-ray diffraction data using deep learning

Powder crystallography is the experimental science of determining the structure of molecules provided in crystalline-powder form, by analyzing their x-ray diffraction (XRD) patterns. Since many materials are readily available as crystalline powder, powder crystallography is of growing usefulness to many fields. However, powder crystallography does not have an analytically known solution, and therefore the structural inference typically involves a laborious process of iterative design, structural refinement, and domain knowledge of skilled experts. A key obstacle to fully automating the inference process computationally has been formulating the problem in an end-to-end quantitative form that is suitable for machine learning, while capturing the ambiguities around molecule orientation, symmetries, and reconstruction resolution. Here we present an ML approach for structure determination from powder diffraction data. It works by estimating the electron density in a unit cell using a variational coordinate-based deep neural network. We demonstrate the approach on computed powder x-ray diffraction (PXRD), along with partial chemical composition information, as input. When evaluated on theoretically simulated data for the cubic and trigonal crystal systems, the system achieves up to 93.4% average similarity (as measured by structural similarity index) with the ground truth on unseen materials, both with known and partially-known chemical composition information, showing great promise for successful structure solution even from degraded and incomplete input data. The approach does not presuppose a crystalline structure and the approach are readily extended to other situations such as nanomaterials and textured samples, paving the way to reconstruction of yet unresolved nanostructures.

Rapid Single‐Step Hydrothermal Synthesis of Phase Pure VO2 (M) with Tailored Morphology

AbstractMonoclinic VO2 (M) is a material of great significance in the study of correlation effects in solids because of its reversible metal‐insulator phase transition between VO2 (M) and VO2 (R) just above the room temperature. Synthesizing pure monoclinic VO2 (M) can be a challenging task due to the formation of other polymorphs such as VO2 (A), VO2 (B), VO2 (D) and VO2 (P) etc. during the synthesis. Additionally, these synthesis techniques involve complex multistep procedures with protective gas environment and controlled reaction parameters clubbed with elongated reaction time ranging from 1 to 7 days which are major obstacles in the mass production of this material. Here we report a novel and rapid synthetic protocol of VO2 (M) for first time using diethylene triamine (DETA) as a reducing and morphology controlling agent in hydrogen peroxide medium. The detailed characterization of prepared materials confirms the formation of phase pure VO2 (M) crystalline powders. The present approach helps to tune these particles from one‐dimensional rods to two‐dimensional petals like structures.

Eggshell derived scaffold of hydroxyapatite-ammonium bicarbonate nano-composite: Bioactivity and cytotoxicity studies

This work investigated the facile synthesis of porous scaffold eggshell derived hydroxylapatite (ESHAp) as a composite with ammonium bicarbonate (AMB) for potential biomaterial in tissue engineering application. The phase purity, composition, size, functional groups and morphology of the apatite were elucidated using high resolution transmission electron microscopy (HTEM), X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR) and scanning electron microscopy (SEM). The results showed that hydroxylapatite (HAp) nanoparticles have round morphologies with average diameters between 20 nm and 80 nm, FT-IR analysis confirmed significant hydroxylapatite functional groups like carbonate, phosphate, and hydroxyl groups, while XRD analysis revealed a well crystalline monophasic HAp powder. The scaffold samples containing 10, 20, 25 and 30 % of AMB withstood a compressive stress up to 5, 20, 30 and 42 N/mm2 respectively which indicates that the compressive stress increased with the AMB content introduced as the pore forming agent. MTT assay performed using MG63 osteosarcoma cell lines showed that on comparing the sample of ESTHAp which contained 0 % AMB with other samples in the range of 0.01–1 mM, viability of above 85 % MG63 cells was achieved except for ESTHAp with 40 % AMB, which showed some level of toxicity. The cell adhesion studies of sintered ESTHAp porous scaffold with different weight percent of the pore forming agents using inverted microscopic images of MG 63 cells incubated with ESTHAp samples and treated with heat at 1000 °C appeared to be unstable in the media used with particle leaching observed, and no cells observed near to the samples.

Calcium Acetate Drug Produced from Rapana venosa Invasive Gastropod Shells: Green Process Control Assisted by Raman Technology.

The highly demanded calcium acetate (Ca(CH3COO)2) for biomedicine and various industries constantly requires green and low-cost methods of synthesis. In the present work, a sustainable approach to produce Ca(CH3COO)2 is reported as a proof of concept, processing for the first time as a starting material the worldwide highly abundant Rapana venosa shells, which is a neglected biogenic waste with high economical potential due to the rich mineral and organic pigmentary content. A green synthesis involving an eco-friendly acetic acid has been optimized at room temperature, without any additional energy consumption, and the resulting saturated Ca(CH3COO)2 solution was further slowly evaporated in three stages to obtain white Ca(CH3COO)2 crystalline powder, without impurity traces. Raman spectroscopy provided efficient structural information for every step of the process control, during demineralization as well as end product validation. Yields as high as 87.5% of highly pure Ca(CH3COO)2 mass have been achieved from raw R. venosa shells, proving the uniqueness and economic viability of the method. X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDX), and Fourier-Transform IR spectroscopy (FTIR) analyses validated the final product identity, hydration status, crystalline morphology, and composition. The purity of the resulting product suggests a high valorization potential of the abundant R. venosa shell in the context of the blue bioeconomy and offers a cleaner and efficient method of Ca(CH3COO)2 production with important applications in relevant industries.

Analysis of Rhodamin B in Lipstick Preparations in Padangsidimpuan City by Thin Layer Chromatography (TLC) Method

Rhodamin B is a synthetic dye in the form of a crystalline powder, green or reddish-purple, odorless, and in solution will be bright red with fluorescence or fluorescence. Rhodamin B is commonly used as a dye in the textile and papermaking industries. Rhodamin B can cause irritation in short-term exposure and has carcinogenic effects. This study aims to find out whether there is Rhodamin B in lipsticks circulating in the Padangsidimpuan City market. Samples were taken by purposive sampling and 5 red samples were obtained. To identify the presence of Rhodamin B, a thin-layer chromatography method was used using eluene as the phase of motion, namely methanol, ethyl acetate, ammonia (50:20:25) and a 254 nm UV lamp The results of the study showed that out of 5 lipstick samples identified, there was one lipstick sample that was identified as containing Rhodamin B.

Tailoring the mechanical and rheological properties of poly(lactic acid) by sterilizing UV-C irradiation

In this study, we irradiated amorphous (A) and semi-crystalline (SC) poly(lactic acid) (PLA) with different UV-C doses up to 2214 kJ/m2. We achieved an average crystallinity of 43 % by heat treatment, which was unaffected by UV-C irradiation. Modulated differential scanning calorimetry showed that crystal polymorphs and the ratio of rigid amorphous and mobile amorphous phases were also unaffected. Using gel permeation chromatography analysis, we showed that the degradation mechanism was noncatalytic random scission, and the initial molar mass was reduced by >90 % at a dose of 2214 kJ/m2 for both A- and SC-PLA samples. Our Raman spectroscopy results indicated that the probability of the formation of oxygen-containing groups increases with increasing UV-C doses. Since we found that the mechanical properties of PLA films can be tailored with UV-C light, we proposed a method to predict the overall tensile curve as a function of the UV-C dose. We also proposed a modified Cross-WLF model to describe the effect of UV-C irradiation on viscosity up to 55 % molar mass reduction. The models allow us to estimate the limits of recyclability and reusability of sterilised PLA products.

Analysis of The Crystalline Phases of The Mineral Rutan By Means of The X-Ray Diffraction Technique

Objective: This work aims to analyze a sample of the mineral Rutana, composed of two crystalline phases of titanium dioxide (TiO2): rutile and anatase, using the X-ray diffraction technique. Theoretical reference: In 1914, the German physicist Max von Laue, using a CaSO4 crystal, successfully achieved the diffraction of X-rays. Crystalline solids, such as CaSO4, consist of regular arrangements of atoms with interatomic spacings of the order of 0.1 -1.0Å, that is, with the same order of magnitude as the wavelength of X-rays. Due to the periodic nature of the internal structure of the crystals, it was possible for them to act as a three-dimensional diffraction grating, providing science with a new method for indirect investigation of the internal structure of materials: the X-ray diffraction (XRD) technique. Methodology: In this technique, a finely ground crystalline powder of a material is placed in the path of a monochromatic x-ray beam. This material, composed of a large number of small crystallites, are randomly oriented. Diffraction occurs from planes of the crystallites that are oriented at the correct angle to fulfill the Bragg condition, in such a way that localized peaks of the same intensity as the diffracted beams are formed. Results and discussion: Based on the intensity, angles and width of the diffraction peaks, the mass percentages of each of the mineral's crystalline phases were obtained: rutile (62.08%) and anatase (37.92%). Research Implications: This work presents a contribution to future research related to the chemical characterization of initially unknown samples, by providing a comprehensive and representative theoretical framework related to the XRD technique. Originality/value: This study presents practical contributions to the literature related to the application of the XRD technique in the characterization of materials.

Ionic Liquid-Accelerated Growth of Covalent Organic Frameworks with Tunable Layer-Stacking.

Layer-stacking behaviors are crucial for two-dimensional covalent organic frameworks (2D COFs) to define their pore structure, physicochemical properties, and functional output. So far, fine control over the stacking mode without complex procedures remains a grand challenge. Herein, we proposed a "key-cylinder lock mimic" strategy to synthesize 2D COFs with a tunable layer-stacking mode by taking advantage of ionic liquids (ILs). The staggered (AB) stacking (unlocked) COFs were exclusively obtained by incorporating ILs of symmetric polarity and matching molecular size; otherwise, commonly reported eclipsed (AA) stacking (locked) COFs were observed instead. Mechanistic study revealed that AB stacking was induced by a confined interlocking effect (CIE) brought by anions and bulky cations of the ILs inside pores ("key" and "cylinder", respectively). Excitingly, this strategy can speed up production rate of crystalline powders (e.g., COF-TAPT-Tf@BmimTf2N in merely 30 minutes) under mild reaction conditions. This work highlights the enabling role of ILs to tailor the layer stacking of 2D COFs and promotes further exploration of their stacking mode-dependant applications.

Ionic Liquid‐Accelerated Growth of Covalent Organic Frameworks with Tunable Layer‐Stacking

AbstractLayer‐stacking behaviors are crucial for two‐dimensional covalent organic frameworks (2D COFs) to define their pore structure, physicochemical properties, and functional output. So far, fine control over the stacking mode without complex procedures remains a grand challenge. Herein, we proposed a “key‐cylinder lock mimic” strategy to synthesize 2D COFs with a tunable layer‐stacking mode by taking advantage of ionic liquids (ILs). The staggered (AB) stacking (unlocked) COFs were exclusively obtained by incorporating ILs of symmetric polarity and matching molecular size; otherwise, commonly reported eclipsed (AA) stacking (locked) COFs were observed instead. Mechanistic study revealed that AB stacking was induced by a confined interlocking effect (CIE) brought by anions and bulky cations of the ILs inside pores (“key” and “cylinder”, respectively). Excitingly, this strategy can speed up production rate of crystalline powders (e.g., COF‐TAPT‐Tf@BmimTf2N in merely 30 minutes) under mild reaction conditions. This work highlights the enabling role of ILs to tailor the layer stacking of 2D COFs and promotes further exploration of their stacking mode‐dependant applications.

Electrokinetic Properties of Cellulose Diacetate—Influence of Morphology and Crystallinity on the Zeta Potential

AbstractThe study presents the electrokinetic properties of the zeta potential and the isoelectric point for cellulose diacetate (CA) in the forms of powder, nonporous film, and porous film. Surface zeta potential (ζ) and isoelectric point (IEP) are important properties that reflect the material's behavior in contact with liquids, as a consequence of the surface charge density and the morphology of the material. Nonporous films are prepared by casting CA solution on glass and Teflon dishes, while the porous film is prepared by the solution blow spinning (SBS) technique. The ζ potential is determined using the streaming potential method in the pH range from 2.5 to 9.5. The influence of the material's crystallinity (CI) and surface roughness (Sa) on the zeta potential is studied. The form of the material (powder, porous film, or nonporous film) influences the electrokinetic properties, which may have consequences on their behavior in contact with liquid (e.g., for processes such as oxidation, surface modification, grafting, or aging during use).

Syntheses of AlLB14(L=Li or Na) crystals using alkali fluorides and its properties

AlLB14 (L=Li or Na or K) crystals were grown using LiF or NaF or KF and crystalline boron powders as the starting materials using a high-temperature Al melt at soaking temperature 1573 ∼ 1773 K for a soaking time of 5 h under an Ar atmosphere. AlLiB14 and AlNaB14 crystals were obtained from LiF or NaF and B powders, and the atomic ratios (n=B/L = 2.0 ∼ 4.0) of starting materials. The AlKB14 crystal was not obtained from KF and B powders as starting materials. The micro-Vickers hardness of AlLB14 crystals is 24(±1) GPa for AlLiB14 and 25(±1) GPa for AlNaB14. The oxidation initiation temperature of AlLiB14 was about 815 K, and the peak due to the exothermic reaction was about 960 K for AlLiB14 and about 990 K for AlNaB14. The final oxidation products were Li2B2O4, Al4B2O9, B2O3, and amorphous phases. The values for the electrical resistivity of the AlLB14 compound were 2.4 ∼ 157 Ω·cm.

Polymer-Based Hydroxyapatite-Silver Composite Resin with Enhanced Antibacterial Activity for Dental Applications.

The primary objective of this investigation was to synthesize a resin incorporating nanoparticles of hydroxyapatite and silver (HA-NpsAg) to enhance biocompatibility and antimicrobial efficacy, thereby facilitating potential implementation within the dental industry. These enhancements aim to ensure reliable, durable, functional, and aesthetically pleasing restorations while concurrently reducing susceptibility to bacterial colonization within the oral cavity. Hydroxyapatite powders were prepared using the sol-gel method and doped with silver nanoparticles obtained by chemical reduction. The crystalline amorphous calcium phosphate powder had a particle size of 279 nm, and the silver nanoparticles had an average diameter of 26.5 nm. Resin spheres containing HA-NpsAg (RHN) were then synthesized at two concentrations (0.5% and 1%) by dissolving the initial monomer mixture in tetrahydrofuran. Subsequent antimicrobial evaluations were conducted via agar diffusion and turbidimetry, employing three strains of Gram-negative bacteria (E. coli, K. oxytoca, and P. aeruginosa) and three strains of Gram-positive bacteria (S. mutans, S. aureus, and B. subtilis). The findings revealed that P. aeruginosa exhibited maximum susceptibility to RHN powder at a concentration of 0.5%, while RHN powder at 1% concentration demonstrated maximal inhibition against S. aureus and S. mutans. Overall, our study highlights the successful synthesis of a dental resin with hydroxyapatite and silver nanoparticles, exhibiting bactericidal properties at low silver concentrations. These findings hold promise for enhancing dental materials with improved antimicrobial efficacy and clinical performance.

Production of dry extracts from sea buckthorn raw materials: Research results

Production of soluble dry extracts from sea buckthorn raw materials is relevant and promising for enterprises of the Republic of Buryatia. The authors have selected technological equipment for obtaining dry extracts: extractor, concentrator, dryer. The possibility of using vacuum-pulse action and the influence of technological factors on the yield of water-soluble substances from sea buckthorn leaves and shoots has been studied. The operating parameters of the technological process have been determined experimentally under production conditions: temperature 45–50 °C, total duration of extraction, concentration and drying 79–111 minutes. The process of obtaining dry extracts is carried out in three stages: water extraction; filtration and concentration; drying in a vacuum pulse dryer. The resulting experimental sample of dry extract from sea buckthorn leaves and shoots is a free-flowing crystalline powder with a moisture content of 4–6 %, highly soluble in water, having high organoleptic characteristics – a natural, well-defined aroma characteristic of sea buckthorn, light brown color. The use of low temperatures and vacuum-pulse modes at the stages of the technological process predicts high safety of thermolabile biologically active substances in the product. The process of obtaining dry extracts from sea buckthorn leaves and shoots has been studied. The results of the studies prove the possibility of producing a dry extract with high organoleptic characteristics using the developed by the authors' technology by equipment whose vacuum-pulse operating modes have a positive effect on the yield of extractives and help reduce time costs along with the intensification of heat and mass exchange processes in sea buckthorn raw materials.

Novel insights into the mechanism of dynamic changes in microstructure and physicochemical properties of corn straw pretreated by ball milling and feasibility analysis of anaerobic digestion

In this study, the effects of Ball milling (BM) pretreatment (0–240 min) on the microstructure, physicochemical properties and subsequent methanogenesis performance of corn straw (CS) were explored, and the feasibility analysis was carried out. The results showed that BM pretreatment destroyed the dense structure of the CS, and the particle size was significantly reduced (D50: 13.85 μm), transforming it into a cell-scale granular form. The number of mesopores increased, the pore volume (PV) (0.032 cm3/g) and specific surface area (SSA) (4.738 m2/g) considerably increased, and the water-absorbent property was improved. The crystalline order of cellulose was disrupted and the crystallinity (CrI) (8.61 %) and crystal size (CrS) (3.37) were remarkably reduced. The cross-links between lignocelluloses were broken, and the relative content and functional groups did not alter obviously. The bulk density (BD), repose angle (RA) and slip angle (SA) dramatically increased. As a result, CS was more readily accessible, attached and utilized by microorganisms and enzymes, causing the hydrolysis and acidification of AD to be greatly facilitated. Compared with the untreated group, the cumulative methane production (CMP) increased by 35.83 %–101.97 %, and the lag phase time (λ) was shortened by 33.04 %–71.17 %. The results of redundancy analysis, Pearson analysis and Mantel test showed that BM pretreatment affects the process of AD by changing the physicochemical factors of CS. The normalization analysis showed that particle size (D90) and BD can be used as direct indicators to evaluate the performance of AD and predict the threshold of biodegradation of CS. Energy analysis and energy conversion assessment showed that BM is a green and efficient AD pretreatment strategy. This result provides a theoretical basis for the industrial application of BM pretreatment towards more energy-efficient and sustainable development.

Morphology-Controlled Ion Transport in Mixed-Orientation Polymers.

Advancing iontronics with precisely controlled ion transport is fundamentally important to bridge external organic electronics with the biosystem. This long-standing goal, however, is thus far limited by the trade-off between the active ion electromigration and idle diffusion leakage in the (semi)crystalline film. Here, we presented a mixed-orientation strategy by blending a conjugated polymer, allowing for simultaneously high ion electromigration efficiency and low leakage. Our studies revealed that edge-on aggregation with a significant percolative pathway exhibits much higher ion permeability than that of the face-on counterpart but encounters pronounced leakage diffusion. Through carefully engineering the mixed orientations, the polymer composite demonstrated an ideal switchable ion-transport behavior, achieving a remarkably high electromigration efficiency exceeding one quadrillion ions per milliliter per minute and negligible idle leakage. This proof of concept, validated by drug release in a skin-conformable organic electronic ion pump (OEIP), offers a rational approach for the development of multifunctional iontronic devices.

Imidazo[1,2-a]pyridine and Imidazo[1,5-a]pyridine: Electron Donor Groups in the Design of D-π-A Dyes.

This work investigates the electron-donating capabilities of two 10-π electron nitrogen bridgehead bicyclic [5,6]-fused ring systems, imidazo[1,2-a]pyridine and imidazo[1,5-a]pyridine rings. Eight compounds with varying positions of electron-withdrawing moieties (TCF or DCI) coupled to the imidazopyridine ring were synthesized and studied. DCI-containing compounds (Ib-IVb) exhibited a purely dipolar nature with broad absorption bands, weak fluorescence, large Stokes shifts, and strong solvatochromism. In contrast, TCF-containing compounds (Ia-IVa) demonstrated diverse properties. Imidazo[1,2-a]pyridine derivatives Ia and IIa were purely dipolar, while imidazo[1,5-a]pyridine derivatives IIIa and IVa displayed a cyanine-like character with intense absorption and higher quantum yields of emission. The observed gradual red shift in optical properties with changing electron-donor groups (IIb < Ib < IIIb < IVb) and (IIa < Ia < IIIa < IVa) underscores the stronger electron-donor character of imidazo[1,5-a]pyridine compared to that of imidazo[1,2-a]pyridine. Furthermore, crystalline powders of imidazo[1,2-a]pyridine derivatives exhibited fluorescence despite minimal emission in solution. Two compounds (Ib and IVa) were successfully formulated into nanoparticles for potential in vivo imaging applications in zebrafish embryos.

Dielectric microwave resonator with large optical apertures for spin-based quantum devices

We demonstrate a low-loss dielectric microwave resonator with an internal quality factor of 2.30×104 while accommodating optical apertures with a diameter of 8 mm. The two seemingly conflicting requirements, high quality factor and large optical apertures, are satisfied, thanks to the large dielectric constant of rutile (TiO2). The quality factor is limited by radiation loss, and we confirmed by numerical simulation that this radiation loss can be suppressed by extending the enclosure height of the resonator; the resonator can potentially achieve a dielectric loss-limited quality factor, exceeding 106. Using this resonator, we performed both continuous-wave (cw) and pulse electron spin resonance (ESR) spectroscopy on 2,2-diphenyl-1-picrylhydrazyl (DPPH) crystalline powder and P1 centers in a diamond crystal in a dilution refrigerator. The cw ESR spectroscopy demonstrated high-cooperativity and strong spin-resonator coupling with the DPPH and P1 centers, respectively, while the pulse ESR spectroscopy successfully measured longitudinal and transverse relaxation times. This optically accessible low-loss microwave resonator enables the implementation of a spin-based quantum device, such as a microwave-optical photon transducer.