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Most of the anticancer compounds synthesized by chemists are primarily evaluated for their direct cytotoxic effects at the cellular level, often overlooking the critical role of the immune system. In this study, we developed a patient‐derived, T‐cell‐retaining tumor organoid model that allows us to evaluate the anticancer efficacy of chemical drugs under the synergistic paradigm of antigen‐specific T‐cell‐dependent killing, which may reveal the missed drug hits in the simple cytotoxic assay. We evaluated clinically approved platinum (Pt) drugs and a custom library of twenty‐eight PtIV compounds. We observed low direct cytotoxicity of Pt drugs, but variable synergistic effects in combination with immune checkpoint inhibitors (ICIs). In contrast, the majority of PtIV compounds exhibited potent tumor‐killing capabilities. Interestingly, several PtIV compounds went beyond direct tumor killing and showed significant immunosynergistic effects with ICIs, outstanding at sub‐micromolar concentrations. Among these, Pt‐19, PtIV compounds with cinnamate axial ligands, emerged as the most therapeutically potent, demonstrating pronounced immunosynergistic effects by promoting the release of cytotoxic cytokines, activating immune‐related pathways and enhancing T cell receptor (TCR) clonal expansion. Overall, this initiative marks the first use of patient‐derived immunocompetent tumor organoids to explore and study chemotherapy, advancing their path toward more effective small molecule drug discovery. [ABSTRACT FROM AUTHOR]

Most of the anticancer compounds synthesized by chemists are primarily evaluated for their direct cytotoxic effects at the cellular level, often overlooking the critical role of the immune system. In this study, we developed a patient‐derived, T‐cell‐retaining tumor organoid model that allows us to evaluate the anticancer efficacy of chemical drugs under the synergistic paradigm of antigen‐specific T‐cell‐dependent killing, which may reveal the missed drug hits in the simple cytotoxic assay. We evaluated clinically approved platinum (Pt) drugs and a custom library of twenty‐eight PtIV compounds. We observed low direct cytotoxicity of Pt drugs, but variable synergistic effects in combination with immune checkpoint inhibitors (ICIs). In contrast, the majority of PtIV compounds exhibited potent tumor‐killing capabilities. Interestingly, several PtIV compounds went beyond direct tumor killing and showed significant immunosynergistic effects with ICIs, outstanding at sub‐micromolar concentrations. Among these, Pt‐19, PtIV compounds with cinnamate axial ligands, emerged as the most therapeutically potent, demonstrating pronounced immunosynergistic effects by promoting the release of cytotoxic cytokines, activating immune‐related pathways and enhancing T cell receptor (TCR) clonal expansion. Overall, this initiative marks the first use of patient‐derived immunocompetent tumor organoids to explore and study chemotherapy, advancing their path toward more effective small molecule drug discovery. [ABSTRACT FROM AUTHOR]

Mounting evidence suggests that strategies combining DNA-damaging agents and stimulator of interferon genes (STING) agonists are promising cancer therapeutic regimens because they can amplify STING activation and remodel the immunosuppressive tumor microenvironment. However, a single molecular entity comprising both agents has not yet been developed. Herein, we designed two PtIV-MSA-2 conjugates (I and II) containing the DNA-damaging chemotherapeutic drug cisplatin and the innate immune-activating STING agonist MSA-2; these conjugates showed great potential as multispecific small-molecule drugs against pancreatic cancer. Mechanistic studies revealed that conjugate I upregulated the expression of transcripts associated with innate immunity and metabolism in cancer cells, significantly differing from cisplatin and MSA-2. An analysis of the tumor microenvironment demonstrated that conjugate I could enhance the infiltration of natural killer (NK) cells into tumors and promote the activation of T cells, NK cells and dendritic cells in tumor tissues. These findings indicated that conjugate I , which was created by incorporating a Pt chemotherapeutic drug and STING agonist into one molecule, is a promising and potent anticancer drug candidate, opening new avenues for small-molecule-based cancer metalloimmunotherapy. [ABSTRACT FROM AUTHOR]

Triggering receptor expressed on myeloid cells‐2 (TREM2) is a key pro‐tumorigenic marker of tumor‐infiltrating macrophages, showing potent immunosuppressive activity in tumor microenvironment. A platinum(IV) complex OPA derived from oxaliplatin (OP) and artesunate (ART) exhibited direct cytotoxicity against human colon cancer cells and immunomodulatory activity to inhibit TREM2 on macrophages in vitro and vivo. Furthermore, OPA deterred the tumor growth in mouse models bearing MC38 colorectal tumor by reducing the number of CD206+ and CX3CR1+ immunosuppressive macrophages; it also promoted the expansion and infiltration of immunostimulatory dendritic, cytotoxic T, and natural killer cells. OPA is the first small‐molecular TREM2 inhibitor capable of relieving immunosuppressive tumor microenvironment and enhancing chemical anticancer efficiency of a platinum drug, thus showing typical characteristics of a chemoimmunotherapeutic agent. [ABSTRACT FROM AUTHOR]

Triggering receptor expressed on myeloid cells‐2 (TREM2) is a key pro‐tumorigenic marker of tumor‐infiltrating macrophages, showing potent immunosuppressive activity in tumor microenvironment. A platinum(IV) complex OPA derived from oxaliplatin (OP) and artesunate (ART) exhibited direct cytotoxicity against human colon cancer cells and immunomodulatory activity to inhibit TREM2 on macrophages in vitro and vivo. Furthermore, OPA deterred the tumor growth in mouse models bearing MC38 colorectal tumor by reducing the number of CD206+ and CX3CR1+ immunosuppressive macrophages; it also promoted the expansion and infiltration of immunostimulatory dendritic, cytotoxic T, and natural killer cells. OPA is the first small‐molecular TREM2 inhibitor capable of relieving immunosuppressive tumor microenvironment and enhancing chemical anticancer efficiency of a platinum drug, thus showing typical characteristics of a chemoimmunotherapeutic agent. [ABSTRACT FROM AUTHOR]

A series of new Li 2 SiO 3 +4 wt% Al 2 O 3 -xK 2 O–B 2 O 3 –SiO 2 (x = 1–4 wt%) LTCC materials were prepared by standard traditional solid-state method and their bulk density, microstructure and crystalline phase composition were shown in detail. The sintering behavior, heat conduction and thermal expansion of the samples were all thoroughly studied. And their microwave dielectric properties were also demonstrated. The bulk density of the samples was enhanced with the addition of 3 wt% KBS glass, and the sintering temperature was reduced from 1020 °C to 900 °C. Meanwhile, the thermal diffusivity of the samples was determined using the LFA447 laser flash apparatus and the specific heat was calculated, according to the results of thermal diffusivity and specific heat, all samples possessed high thermal conductivity ranging from 5.5 ± 0.02 W/mK to 8.6 ± 0.08 W/mK. Furthermore, the attractive flexural strength and average coefficient of thermal expansion reach to 270 MPa and 15.7 × 10−6/K (at 100 °C), respectively. The reduction of the sintering temperature is attributed to the addition of KBS glass which reduces the crystallization activation energy of the samples. Besides, increasing bulk density can substantially reduce pores in the grain boundary, which has great effects on phonon scattering, improving the thermal conductivity. [ABSTRACT FROM AUTHOR]

Novel CaAl 2 x B 2 O 4+3 x (x = 0.25, 0.5, 0.75, and 1) ceramics were prepared via solid-state reaction method. The investigation is concentrated on sintering behavior, phase composition and dielectric properties of CaAl 2 x B 2 O 4+3 x ceramics with various ratios of Al 2 O 3 content. The optimal sintering temperature and the content of CaAl 2 B 2 O 7 are highly related to the variation of x value. CaAl 2 x B 2 O 4+3 x ceramics possess excellent microwave dielectric properties: ε r = 5.8 ± 0.05, Q × f = 63,338 ± 2690 GHz (@13.57 GHz), and τ f =-29 ± 2 ppm/℃ when sintered at 940 ℃ for x = 0.5. Comparing the properties of CaAl 2 x B 2 O 4+3 x ceramics with reported borate ceramics, the ceramics prepared in this study with low dielectric loss and low sintering temperature have promising prospects in LTCC technology. [ABSTRACT FROM AUTHOR]

In this study, intrinsic dielectric properties of monoclinic A 0.5 Zr 0.5 NbO 4 ceramics (A = Mn, Zn, Mg, Co, Ni) with wolframite structure were investigated by chemical bond theory, infrared and terahertz spectroscopy. According to bond theory, Zr–O bonds and A-O bonds with larger bond susceptibility values provide majority contributions to relative permittivity; while Nb–O bonds dominate the structural stability and oxygen polyhedron distortion. Intrinsic dielectric properties calculated via far-infrared reflectivity spectroscopy are close to experimental properties, which indicates that most of dielectric contributions come from absorptions of structural phonon oscillation and infrared modes of dielectric response in A 0.5 Zr 0.5 NbO 4 ceramics vary with A-site ions. Furthermore, intrinsic properties estimated by terahertz time domain spectra also testify the effectiveness of theoretical dielectric properties. [ABSTRACT FROM AUTHOR]

Structure‐property relationships of Y2MgTiO6, a type of double perovskite materials, were investigated systematically. Rietveld refinement of XRD patterns confirmed that Y2MgTiO6 belongs to the P21/c space group and has a structure analogous to that of monoclinic Dy2MgTiO6. In accordance with the observed number of vibrational bands and group theoretical predictions, O and Y ions at the 4e site dominated the Raman peaks. The IR reflectivity spectrum indicated that the major contributions to the relative permittivity and intrinsic loss were modes lower than 500 cm−1. The measured relative permittivity closely approached the calculated values determined according to P‐V‐L theory, the Clausius‐Mossotti equation and IR fitted results. The larger bond energy for Mg–O bonds than for Ti–O bonds corresponds to a more stable octahedron of [MgO6], as verified by the octahedral distortion. Satisfactory microwave dielectric properties of Y2MgTiO6 ceramics were as follows: εr = 20.4 ± 0.8, Q × f = 42 060 ± 310 GHz, τf = −52 ± 3 ppm/°C, sintered at 1450°C. [ABSTRACT FROM AUTHOR]

Gd2Zr3(MoO4)9 is a double trigonal molybdate crystallized in the space group R3¯c. The optimal microwave dielectric properties were achieved via solid‐state reaction at 725°C for Gd2Zr3(MoO4)9 ceramics: εr = 11.17, Q × f = 57 460 GHz, τf = −31.91 ppm/°C. The three‐dimensional framework type structure is formed by mixed MoO4 tetrahedron and ZrO6/GdO9 polyhedron. The analysis based on complex chemical bond theory shows that the Mo–O bonds account for majority contribution to controlling microwave dielectric properties. The MoO4 tetrahedron and ZrO6 octahedron stabilize the crystal structure by strong binding ability. As it was shown by Raman spectroscopy, the Raman‐active vibrations primarily originate from MoO4 tetrahedron, similarly to molybdate analogies. [ABSTRACT FROM AUTHOR]

Coordination chemistry, bond state and vibrational spectrum of co-substituted microwave dielectric NdNb 1- x (Zr 0.5 W 0.5) x O 4 ceramics (x = 0.01∼0.05) were investigated. Raman spectra and XRD refinement showed a solid solution was formed. The compressed and elongated chemical bonds are responsible for the variations of crystal parameters and cell volume. Calculated chemical bond parameters indicated bond covalency, lattice energy and Nb-site bond energy act on the fluctuations of the permittivity, quality factor and temperature coefficient, respectively. Meanwhile, the infrared vibrational spectrum is fitted to quantify the contributions of observed IR mode to the intrinsic loss. Compact ceramic possesses excellent properties: ε r ∼ 19.2, Q × f ∼ 55282 GHz and τ f ∼ -11.36 ppm/°C with x = 0.04, at 1250°C. [ABSTRACT FROM AUTHOR]

Li 2 Mg 2.88 Ca 0.12 TiO 6 (LMCT) was modified by silane coupling agent (C 14 H 19 F 13 O 3 Si, F8261), and then filled in polytetrafluoroethylene suspension (PTFE) using hot treating approach. The weight fraction of LMCT varied from 30 to 70 wt %. XRD patterns presented the crystal phase of LMCT powders. The analyses of TEM, XPS, and FTIR were performed to characterize the surface states of LMCT fillers. The effects of LMCT filling content on the microstructure and dielectric properties were also investigated. Several theoretical models were discussed and compared with the dielectric constant of LMCT/PTFE substrates with respect to different LMCT content. Furthermore, the temperature and frequency dependence of dielectric constant were also considered on the composites. At last, the LMCT/PTFE composite substrates possessed relatively high dielectric constant (ε r = 4.33) and extremely low dielectric loss (tan δ = 0.001) at filler loading of 50 wt % LMCT. • Li 2 Mg 2.88 Ca 0.12 TiO 6 (LMCT) were modified by C 14 H 19 F 13 O 3 Si (F8261). • The ε r of LMCT/PTFE composites increased with increase of LMCT content. • The ε r of modified LMCT/PTFE matched well with Lichtenecker model. • LMCT/PTFE exhibited ε r of 4.33 and tan δ of 0.001 at 50 wt % LMCT loading. [ABSTRACT FROM AUTHOR]

In this study, intrinsic dielectric properties of ZnNb2O6 ceramics were investigated using P–V–L chemical bond theory and far‐infrared reflectivity spectra. The largest bond ionicity and bond susceptibility of Nb–O bonds suggest that the dielectric polarizability is mainly determined by Nb–O bonds. Relative permittivity, calculated via P–V–L bond theory, is close to experimental value determined using TE011 mode. The Nb–O bonds are also crucial for the structural stability. According to far‐infrared reflectivity spectra and complex dielectric function analysis, a relatively consistent result between calculated and measured dielectric properties, fit using classical damped oscillator mode, indicate that the B1u mode at 168.87 cm−1 provides majority contribution to the dielectric properties. [ABSTRACT FROM AUTHOR]

In this study, the crystal structure, phase composition, Raman spectrum, and microwave dielectric properties of novel Co 0.5 Zr 0.5 TaO 4 ceramics were investigated. Based on the X-ray diffraction, Rietveld refinement analysis and Raman spectroscopy, a coexistence of monoclinic-type and trirutile tetragonal phases was confirmed in the temperature range of 1100–1200 °C. The variations of relative density, growth of grain, and contents of each phase are mainly responsible for the developments of microwave dielectric properties of Co 0.5 Zr 0.5 TaO 4 ceramics. Excellent microwave dielectric properties with a ε r of 20.19, a Q × f about 65125 GHz and a τ f ca. of −39.02 ppm/oC were obtained when sintered at 1150 °C. [ABSTRACT FROM AUTHOR]

Monoclinic Sm 2 O 3 ceramics were prepared using the conventional solid-state sintering method. The influences of sintering temperature on structure, morphology, and performance of Sm 2 O 3 ceramics were studied systematically. The excellent microwave dielectric properties (ε r = 21.95, Q × f = 47,000 GHz, and τ f = +30.15 ppm/°C) were achieved in Sm 2 O 3 ceramic sintered at 1550 °C for 4 h. Interestingly, varying degrees of cracking were observed after the sintered samples were placed for a short time, with the extent depending on the sintering temperatures. The reasons for cracking were analyzed through chemical bond characteristics and microstructure. The analysis of bond valence and microstructure revealed that Sm 2 O 3 ceramics sintered at higher temperatures exhibited larger bond strain index, global instability index, and interplanar spacings. These results suggest that the cracking of Sm 2 O 3 ceramics originates from inner stress resulting from structural variations caused by variations in sintering temperatures. The effect of MgO addition on microwave dielectric properties and stability of Sm 2 O 3 ceramics was also investigated. Phase identification and elemental distribution indicated that MgO existed as a secondary phase. The Sm 2 O 3 ceramic with 20 wt% MgO addition exhibited optimal microwave dielectric properties: ε r = 17.72, Q × f = 61,100 GHz, and τ f = +2.4 ppm/°C. Importantly, cracking was not observed when MgO addition amounts were 5 wt% or higher. The attractive microwave dielectric properties and favorable stability confirm the possibility of the 5G applications for Sm 2 O 3 /MgO composite ceramics. [ABSTRACT FROM AUTHOR]

Monoclinic Sm 2 O 3 ceramics were prepared using the conventional solid-state sintering method. The influences of sintering temperature on structure, morphology, and performance of Sm 2 O 3 ceramics were studied systematically. The excellent microwave dielectric properties (ε r = 21.95, Q × f = 47,000 GHz, and τ f = +30.15 ppm/°C) were achieved in Sm 2 O 3 ceramic sintered at 1550 °C for 4 h. Interestingly, varying degrees of cracking were observed after the sintered samples were placed for a short time, with the extent depending on the sintering temperatures. The reasons for cracking were analyzed through chemical bond characteristics and microstructure. The analysis of bond valence and microstructure revealed that Sm 2 O 3 ceramics sintered at higher temperatures exhibited larger bond strain index, global instability index, and interplanar spacings. These results suggest that the cracking of Sm 2 O 3 ceramics originates from inner stress resulting from structural variations caused by variations in sintering temperatures. The effect of MgO addition on microwave dielectric properties and stability of Sm 2 O 3 ceramics was also investigated. Phase identification and elemental distribution indicated that MgO existed as a secondary phase. The Sm 2 O 3 ceramic with 20 wt% MgO addition exhibited optimal microwave dielectric properties: ε r = 17.72, Q × f = 61,100 GHz, and τ f = +2.4 ppm/°C. Importantly, cracking was not observed when MgO addition amounts were 5 wt% or higher. The attractive microwave dielectric properties and favorable stability confirm the possibility of the 5G applications for Sm 2 O 3 /MgO composite ceramics. [ABSTRACT FROM AUTHOR]

Abstract The dependence of the bond characters and crystal structure on microwave dielectric properties of NdNb 1- x (Mg 1/4 W 3/4) x O 4 (x = 0.02–0.06) solid solution ceramics is investigated. X-ray diffraction and Rietveld refinement analysis both indicate a formation of single monoclinic phase in the whole range. Based on complex chemical bond theory, theoretical dielectric constant of the complex crystal is slightly lower than observed one, which is consistent with the analysis of infrared reflectivity spectra. The Q × f (quality factor) values are associated with the total lattice energy and average grain size. Increment of Nb-site bond energy generates a more stable structure, which makes τ f (temperature coefficient of resonant frequency) continuously move towards zero. Besides, far-infrared reflectivity spectra illustrates that low-frequency modes play primary role of intrinsic dielectric properties. Excellent microwave dielectric properties and an optimal combination are: ε r = 19.59, Q × f = 50339 GHz, τ f = −39.62 ppm/°C at x = 0.04. Highlights • NdNb 1- x (Mg 1/4 W 3/4) x O 4 (x = 0.02–0.06) solid solution ceramics have excellent microwave dielectric properties. • Far-infrared reflectivity spectra illustrates that low-frequency modes play primary role of intrinsic dielectric properties. • The relationship between microwave dielectric properties and the chemical bonds characteristics is investigated. [ABSTRACT FROM AUTHOR]

Abstract In the present study, influences of Ta5+ substitution on Nb site on crystal structural evolution, Raman spectra and microwave dielectric properties of Zn 0.15 Nb 0.3- x Ta x Ti 0.55 O 2 (0 ≤ x ≤ 0.3) ceramics were investigated. Bond ionicity, lattice energy and octahedral distortion of Zn 0.15 Nb 0.3- x Ta x Ti 0.55 O 2 structure calculated based on chemical bond theory and Rietveld refinement analysis were used together to understand correlation between crystal structure and microwave dielectric properties. The results showed that rutile Zn 0.15 Nb 0.3- x Ta x Ti 0.55 O 2 solid solutions could be synthesized in whole composition range of x = 0–0.3. With increase of x value, cell volume and bond length are reduced, which is confirmed by blue shift of Raman vibrational peaks. Dielectric constant (ε r) is closely related to average Nb O bond ionicity. Quality factor (Q × f) values and temperature coefficient values of resonant frequency (τ f) are mainly affected by lattice energy and octahedral distortion respectively. In Zn 0.15 Nb 0.3- x Ta x Ti 0.55 O 2 ceramics, proper substitution of Ta5+ ion efficiently improves Q × f values and reduces the τ f values. Optimal microwave dielectric properties of ε r = 75.87, Q × f = 22050 GHz and τ f = 234.6 ppm/°C were obtained for Zn 0.15 Nb 0.3- x Ta x Ti 0.55 O 2 solid solutions at x = 0.2 when sintered at 1100 °C. [ABSTRACT FROM AUTHOR]

Abstract Three sets of polyfluorenes grafting one/two orange emissive groups on central or terminal fluorene unit have been synthesized successfully through the catalyst-transfer polymerization. The molecular weights linearly increase with increase in the feed ratios of [monomer]/[catalyst] in a certain molecular weight range. The initiators with bis(2,6-diisopropylphenyl)imidazolin-2-ylidene) (IPr) as the ancillary ligand show better catalytic activity, leading to higher molecular weight of up to 126.3 kDa. All polymers in toluene have the similar absorption spectra to polyfluorene homopolymer, while the weak absorption bands of 420–500 nm are observed only in the polymers with low molecular weight. Photoluminescence spectra display a dominant blue emission from the polyfluorene backbone and a weak orange emission (508–661 nm) from the orange group. The clearly enhanced orange emission in the polymers with low molecular weight is mainly ascribed to the intramolecular Förster energy transfer from the polyfluorene segment to the orange group, which is further confirmed by the electroluminescent behavior of the polymers. Graphical abstract Image 1 Highlights ● Well-defined polyfluorenes grafting one or two orange emissive groups on central or terminal fluorene unit are successfully synthesized through the catalyst-transfer polymerization. ● Intramolecular Fӧrster energy transfer from polyfluorene segment to the orange group is related to the number and position of the orange emissive group chemically located in the polymer chain. ● The warm white emission can be achieved in the high molecular weight polymers containing orange emissive group(s) through the incomplete energy transfer. [ABSTRACT FROM AUTHOR]

A PtIV prodrug (PDMA) exhibits great potential for the therapy of metastatic triple-negative breast cancer (TNBC) through a synergistic action of antiangiogensis and antimetastasis. [ABSTRACT FROM AUTHOR]

Abstract Structure-property relationship of co-substituted (Mg2+ 1/4 Mo6+ 3/4)5+, (Al3+ 1/3 Mo6+ 2/3)5+, (Si4+ 1/2 Mo6+ 1/2)5+, (Zr4+ 1/2 Mo6+ 1/2)5+ for Nb5+ in NdNbO 4 ceramics was investigated systematically. The remarkable differences in dielectric properties of each composition originated from their bond characteristics and structure stability. The elongated/compressed bonds have an effect on the cell volume and polarization. And the average bond covalency of Nb-O bond was responsible for the development of permittivity. Q×f values and the total lattice energy went up to maximum when (Si 0.5 Mo 0.5) occupied Nb-site. Variations of lattice energy together with Nb-O bond energy suggest that a more stable structure was obtained through co-substitution. The optimal microwave dielectric properties is: ε r = 18.97, Q×f = 49466 GHz, τ f = 7.34 ppm/°C for NdNb 0.97 (Si 0.5 Mo 0.5) 0.03 O 4 , sintered at 1250 °C. [ABSTRACT FROM AUTHOR]

Abstract In this study, the influence of substitution of Zr for Ti on crystal structure and microwave dielectric properties of Zn 0.15 Nb 0.3 (Ti 1- x Zr x) 0.55 O 2 (0 ≤ x ≤ 0.7) ceramics were discussed through Rietveld refinement, normalized bond analysis and complex chemical bond theory. Rietveld refinement analysis indicated that a composite could be formed for x ≤ 0.22. Pure orthorhombic type (O-type) solid solutions are prepared in the region of x = 0.3–0.7. With the increasing amount of ZrO 2 , cell volume of O-type phase increases, and it results in the enlarging and compressing behaviors of chemical bonds. Under the circumstances, the dielectric polarizability is deteriorated because of the reducing chemical bond covalency value (f c), and this finding is also confirmed by Clausius-Mosotti equation. Lattice energy of Zr–O1 bonds and grain size distribution of sintered specimens are mainly responsible for the variations of quality factor (Q × f) value. Chemical bond energy (E) is closely related with the temperature coefficient of resonant frequency value (τ f). Typical microwave dielectric properties of Zn 0.15 Nb 0.3 (Ti 1- x Zr x) 0.55 O 2 ceramics (x = 0.22) were obtained when sintered at 1100 °C: ε r = 46.31, Q × f = 30,297 GHz, τ f = -8.24 ppm/°C. [ABSTRACT FROM AUTHOR]

NdNb1−x(Al1/3W2/3)xO4 (x = 0.03–0.07) solid solution compounds were synthesized and characterized via solid-state reaction. XRD patterns reveal the formation of a single fergusonite phase, and the dependence of microwave dielectric properties on its structural characteristic was investigated based on Rietveld refinements together with complex chemical bond theory. The variation of dielectric constant is attributed to the Nb/Al1/3W2/3–O bond ionicity. The grain size and total lattice energy are both associated with quality factor, and the temperature coefficient is affected by oxygen and bond valence of the Nb site. Infrared reflectivity spectrum analysis illustrated that the permittivity is primarily due to ion polarization in the microwave frequency region. Notably, the following properties of NdNb1−x(Al1/3W2/3)xO4 (x = 0.04) ceramics were obtained: εr∼ 19.04, Q×f∼ 58 219 GHz and τf∼−41.14 ppm/°C. [ABSTRACT FROM AUTHOR]

Two PtIV–artesunate anticancer prodrugs that target RAD51, a crucial protein in homologous recombination mediating the sensitivity of cancer cells to DNA-damaging agents, were designed; their cytotoxicities against BRCA-proficient ovarian and breast cancer cells are significantly higher than those of cisplatin. [ABSTRACT FROM AUTHOR]

In this study, the preparation, phase constitution, microstructure and dielectric properties of GaNbO 4 ceramics were investigated. Prepared via traditional solid-state reaction method at 1000–1080 °C, the GaNbO 4 ceramics existed as a composite of two allomorphic GaNbO 4 phases: α-GaNbO 4 (monoclinic, space group P 2/ c , Z = 2) and β-GaNbO 4 (monoclinic, space group C2, Z = 4). The contents of α and β GaNbO 4 phases changed with the change of sintering temperature. The GaNbO 4 ceramics showed a microstructure with closely packed grains in two different sizes and shapes. The GaNbO 4 sintered at 1060 °C exhibited typical values of ε r  = 15.8, Q  ×  f  = 101,000 GHz and τ f  = −63.4 ppm/°C. [ABSTRACT FROM AUTHOR]

In this paper, the BaONd2O3TiO2 (BNT) ceramics are synthesized at low temperature with the assistance of Li2OB2O3SiO2 (LBS) and BaOZnOB2O3 (BZB) glasses. The influences of glasses on the sintering behavior, phase composition, microstructure, activation energy (Ea) on the BNT ceramics are studied in detail. The results show that a new phase, Ba2LiB5O10, is formed from the chemical reaction between LBS and BZB glasses. The sintering temperature of BNT ceramics can be effectively reduced by 450 °C due to the synergetic effect of LBS and BZB glasses and the appearance of Ba2LiB5O10 phase. [ABSTRACT FROM AUTHOR]

Usually, the quality factor of a binary-phase ceramic will increase if the volume molar ratio of the high quality factor component increases, and vice versa. However, the quality factor of the Ba 6-3 x Ln 8+2 x Ti 18 O 54 - LnAlO 3 (Ln = Nd, Sm, La) ceramics keeps a constant (~ 2200 ± 200 at 4 GHz) as the volume molar ratio of LnAlO 3 (~ 9000 at 7 GHz) increases. While previous studies reported the importance of microstructure variation, here by fitting the dielectric constant, via definition we derived a quality factor calculation formula that can precisely determine the quality factor as the volume molar ratio changes, which is of great significance for guiding the ceramic manufacturing. [ABSTRACT FROM AUTHOR]

Six aryl Pd(II) bromide complexes based on perylene diimide derivative (Ar) and phosphine mixed-ligands are successfully synthesized by directly oxidative addition of Ar-Br to the Pd(0) precursor. These complexes with the general formulas ArPdBr(PCy3)2 (PCy3 = tricyclohexylphosphine; Pd1-Pd3) and [ArPdBr(TXP-2,4)]2 (TXP-2,4 = tri-2,4-xylylphosphine; Pd4-Pd6) are stable and can be handled in air at room temperature. By employing the Pd(II) complexes as initiators, Suzuki catalyst transfer polymerization (SCTP) of AB-type fluorene monomer is investigated for preparing polyfluorenes (PFs) with the defined end group. Complexes Pd4-Pd6 with auxiliary TXP-2,4 ligand can initiate polymerization of AB-type fluorene monomer at room temperature, while higher polymerization temperature is required for Pd1-Pd3 with alkyl phosphine PCy3. The obtained polymers are analyzed by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry, which confirms that the Ar group is appended to the terminus of the polymer chain. Moreover, PFs prepared by Pd4-Pd6-catalyzed SCTP bear precisely the Ar group on one chain end and 4- tert-butylphenyl end-capping group on the opposite end, which indicates that Pd4-Pd6 with the bulky TXP-2,4 exhibit better catalytic performance in SCTP. Photoluminescence spectra of the obtained polymers show a dual or a blue emission resulting from the difference of the molecular weight. [ABSTRACT FROM AUTHOR]

A series of aryl Pd(II) complexes of the formula PdL 2 (Ar)Br (L = PPh 3 , 1 – 8 ; L = PCy 3 , 9 – 11 ; L = PEt 3 , 12 ) and [Pd(P( o -tol) 3 )(Ar)( μ -Br)] 2 ( 13 – 18 ; Ar = substituted phenyl with simple functional group, Cy = cyclohexyl, o -tol = o -tolyl) has been synthesized by direct oxidative addition of Pd(0) precursor and excess aryl bromide. In contrast, the corresponding Pd(II) bromide coordinated with partly aryl-aryl exchanged phosphine was isolated for the bidentate 1,2-bis(diphenylphosphino)ethane (dppe) or 1,3-bis(diphenylphosphino)propane (dppp) ligand, indicating that the aryl-aryl exchange occurs more easily probably because of the chelate effect of the bidentate ligand and the intramolecular π-π interaction between neighboring phenyl rings. Suzuki-Miyaura coupling polymerization of AB-type fluorene monomer with these Pd(II) complexes as initiators was carried out. The aryl Pd(II) complexes with P( o -tol) 3 exhibit the catalyst-transfer polymerization at room temperature. Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) characterization and end group analysis reveal that the functional group is anchored at the end of polymer backbone. Furthermore, the groups can be transferred to other more useful active groups via simple organic reaction. [ABSTRACT FROM AUTHOR]

Abstract: Microwave dielectric properties of (1− x)BaZn2Ti4O11–xBaNd2Ti4O12 (x =0–1.0) ceramics were investigated by the solid-state reaction with the purpose of finding a microwave ceramics with high dielectric constant (ɛ r), high quality factor (Q × f) and low temperature coefficient of resonant frequency (τ f). A two phase system BaZn2Ti4O11–BaNd2Ti4O12 was formed and SEM photographs show equiaxed BaZn2Ti4O11 grains and columnar BaNd2Ti4O12 grains. The microwave dielectric properties were strongly determined by the chemical composition. As increasing x from 0 to 1.0, the phase composition varied from pure BaZn2Ti4O11, to the two phase system BaZn2Ti4O11–BaNd2Ti4O12 and then to pure BaNd2Ti4O12. Therefore, the ɛ r raised from 29.1 to 82.0 and the Q × f values decreased from 54,630GHz to 8110GHz, and the τ f values increased from −29ppm/°C to 94ppm/°C. 0.8BaZn2Ti4O11–0.2BaNd2Ti4O12 ceramics sintered at 1250°C for 2.5h had ɛ r =39.1, Q × f =37,850GHz and τ f =−9ppm/°C. [Copyright &y& Elsevier]

Abstract: In this work, the LTCC composite materials containing fused silica and monoclinic zirconia ceramic particles, respectively, which based on the composite matrix composed of the barium borate glassy matrix and α-alumina ceramic particles, were prepared by traditional solid-state preparation process at a sintering temperature of 900°C. Sintering mechanism and physical properties, e.g. dielectric properties and coefficient of thermal expansion (CTE), of the LTCC composite ceramics are investigated and discussed in detail in terms of their mineral phase composition. The results indicate that a barium borate glassy phase can be easily formed from a barium borate compound, which is obtained by the chemical combination of barium hydroxide octahydrate and an aqueous solution of boric acid, at a sintering temperature of 900°C. In turn, the barium borate glassy melts can supply a liquid phase sintering aid for the fabrication of the LTCC composite ceramics with the sintering temperature of 900°C during sintering. The introduction of the α-alumina ceramic particles to the barium borate glassy matrix can improve the sintering behavior whereas the presence of fused silica or monoclinic zirconia particles in the composite ceramics is important to adjust the dielectric, thermal and mechanical properties of the LTCC composite materials. The work may be referenced for the fabrication of multi-layer LTCC structures with tailored physical properties. [Copyright &y& Elsevier]

Abstract: The behavior of dielectric and microwave properties against sintering temperature has been carried out on CaO–SiO2–B2O3 ceramic matrix composites with ZrO2 addition. The results indicated that ZrO2 addition was advantageous to improve the dielectric and microwave properties. X-ray diffraction (XRD) patterns show that the major crystalline β-CaSiO3 and a little SiO2 phase existed at the temperature ranging from 950°C to 1050°C. At 0.5wt% ZrO2, CaO–SiO2–B2O3 ceramic matrix composites sintered at 1000°C possess good dielectric properties: ɛ r =5.85, tan δ =1.59×10−4 (1MHz) and excellent microwave properties: ɛ r =5.52, Q · f =28,487GHz (11.11GHz). The permittivity of Zr-doped CaO–SiO2–B2O3 ceramic matrix composites exhibited very little temperature dependence, which was less than ±2% over the temperature range of −50 to 150°C. Moreover, the ZrO2-doped CaO–SiO2–B2O3 ceramic matrix composites have low permittivity below 5.5 over a wide frequency range from 20Hz to 1MHz. [Copyright &y& Elsevier]

Abstract: In this work, a low-temperature co-fired ceramic (LTCC) composite based on the eutectic system BaO–ZnO–SiO2–B2O3 is fabricated. The phase formation in the LTCC composite is investigated by XRD, SEM and DSC technologies. Dielectric and thermal properties are discussed in terms of the phase composition. The results indicate that major mineral phases of the LTCC composite are barium silicate, willemite, SiO2 crystal phases and additional quartz. Due to the peculiar physical characteristics of these mineral phases, the LTCC composite can express different dielectric and thermal properties along with the evolution of the major mineral phases. [Copyright &y& Elsevier]

Abstract: Magnesium titanate (MgTiO3) powders have been prepared and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effects of calcination temperature and MgO: TiO2 ratios on phase formation, morphology and particle size distribution of the proposed powders are examined. Single-phase MgTiO3 can be synthesized by heating the non-stoichiometrically 1.03MgO–1TiO2 at 1100°C for 3h. The densification, microstructural evolution and microwave dielectric characteristics of 0.935MgTiO3–0.065CaTiO3 (935MCT) compound are developed. It is found that the content of ZnNb2O6 has an apparent effect on the physical properties and the microwave dielectric characteristics of 935MCT ceramics. The 935MCT sample with 5wt% of ZnNb2O6, sintered at 1300°C for 2h, was measured to show excellent microwave dielectric properties: ɛ r equal to 22.5, Q × f value equal to 93,561GHz (at 9GHz) and τ f equal to 6.2ppm/°C. [Copyright &y& Elsevier]

The low-fired (ZnMg)TiO3–TiO2 (ZMT–TiO2) microwave ceramics using low melting point CaO–B2O3–SiO2 as sintering aids have been developed. The influences of Mg substituted fraction on the crystal structure and microwave properties of (Zn1− xMg x)TiO3 were investigated. The result reveals that the sufficient amount of Mg ( x ≥ 0.3) could inhibit the decomposition of ZnTiO3 effectively, and form the single-phase (ZnMg)TiO3 at higher sintering temperatures. Due to the compensating effect of rutile TiO2 (τf = 450 ppm/°C), the temperature coefficient of resonant frequency (τf) for (Zn0.65Mg0.35)TiO3–0.15TiO2 with biphasic structure was adjusted to near zero value. Further, CaO–B2O3–SiO2 addition could reduce the sintering temperature from 1150 to 950 °C, and significantly improve the sinterability and microwave properties of ZMT–TiO2 ceramics, which is attributed to the formation of liquid phases during the sintering process observed by SEM. The (Zn0.65Mg0.35)TiO3–0.15TiO2 dielectrics with 1 wt% CaO–B2O3–SiO2 sintered at 950 °C exhibited the optimal microwave properties: ε ≈ 25, Q × f ≈ 47,000 GHz, and τf ≈ ± 10 ppm/°C. [ABSTRACT FROM AUTHOR]

Pb(Zr0.55Ti0.45)O3 (PZT) thin films with different grain size have been fabricated by controlling the post-annealing process. PZT thin films nucleated at 550°C and the grains began growing above 650°C. Long nucleation process time but relatively short growth process time resulted in small grain. In contrast, long growth process time but short nucleation process time resulted in large grain size. PZT thin films with different grain size show different electrical properties. The polarization increases with the increase of grain size. However, the coercive field exhibites a paraboliclike relationship with grain size. The coercive field increases with the increase of grain size below 70 nm, whereas decreases as the grain size increases above 70 nm. The grain size of 70 nm is thought to be the critical size for the domain structure transition. While increasing the grain size, PZT thin films experience a transition from single domain state to multi domain state, which is related to the polarization switching. It is well known that the polarization of ferroelectric thin films with multi domain structure switches much easier than that with single domain structure. Obviously, the coercive field dependence on the grain size is interpreted. [ABSTRACT FROM AUTHOR]

Abstract: The Cu/Ti multilayer (ML) films were deposited on Si(100) and Si(111) substrate with a series of pair layers with Vanguard sputtering system. The influences of periodic number and substrate structure on UV-reflectivity of Cu/Ti superlattice films were investigated carefully. The result shows that the Cu/Ti ML films have clear layer-structure. The ML films deposited on Si(100) and Si(111) have UV-reflectivity of about 90% and 67% at 200nm, respectively, but they have lower soft X-ray reflectivity of about 1.9% at 13.04nm in terms of wavelength, with near normal incidence of 5°. The transmission microscope image indicates that the fabricated Cu/Ti ML films have superlattice structure. [Copyright &y& Elsevier]

Lead zirconate titanate Pb(Zr 0.52 Ti 0.48 )O 3 (PZT) thin films was successfully deposited on Pt(111)/Ti/SiO 2 /Si(100) substrates by a new modified sol-gel technique: precursor-monomer method. In this process three separated Pb 2 + , Zr 4 + , Ti 4 + precursor-monomers and metal chelating agents were mixed together to prepare PZT sol-solution (precursor). The precursor-monomer method has several advantages over conventional sol-gel methods, including easy change the atomic ratio of Pb 2 + /Zr 4 + /Ti 4 + and doping metallic ions, rapid PZT precursor synthesis, low processing temperature, without dry condition and distillation, long storage period, simplicity and low cost, etc. The paper investigated the effects of hydrolysis degree on the stability of PZT precursor, and it was found that the sample with 12.5% (v/v) adding water had the longest storage time. The inference of lead titanate (PbTiO 3 , PT) seeding layers on the microstructures, surface morphologies and ferroelectric properties of PZT films has also been systematically examined. We found that PZT films with PT/PZT/PT structure had lower perovskite phase crystallization temperature, larger grain size, better microstructure and ferroelectric properties as compared with no PT seeding layers films. [ABSTRACT FROM AUTHOR]

Abstract: The effect of Yb/Mg co-doping on the microstructure and electrical properties of BaTiO3 ceramics sintered under oxidizing, reducing and annealed conditions was investigated. XRD analyses indicated the suppression of the solubilities of the acceptor ions in BaTiO3 under the reducing and annealed conditions. DSC measurements indicated that addition of too much Yb would cause the collapse of the core-shell structure in the BaTiO3 ceramics. The effect of sintering atmospheres on the microstructure and dielectric properties was attributed to the change of the solubilities of the acceptor ions in this core-shell-structured material. [Copyright &y& Elsevier]

The variations of polarization and dielectric properties with the grain size of PZT films have been investigated experimentally and theoretically. It is revealed that polarization increases much more quickly with the grain size than dielectric constant does. The polarization increases as the grain size increases and is saturated when the grain size is about 60nm, whereas the dielectric constant is saturated when the grain size is about 70 nm. Because the dielectric response of ferroelectrics is affected by the domain switching and exhibits hysteresis, the contribution of domain dynamics to the dielectric properties must be considered. Varying grain size will change the domain dynamics due to the close relationship of domain width and grain size. Based on the Landau-Ginzburg (LG) model, the variations of remnant polarization and dielectric constant against grain sizes have been investigated, considering the contribution of domain motion. The calculation result is consistent with the experimental result. [ABSTRACT FROM AUTHOR]

High performance X7R dielectric materials were prepared by doping Nb2O5–Co3O4 nanometer composite oxide to BaTiO3 powders, with a dielectric constant as high as 5200 and dielectric loss lower than 1.0%, when they were sintered at 1300 for 2 h. The effect of Nb2O5–Co3O4 nanometer composite oxide was discussed. It was concluded that Nb5+, Co3+ were easier to incorporate into BaTiO3 lattice by using Nb2O5–Co3O4 nanometer composite oxide as dopants than by doping Nb2O5, Co3O4 separately. It was favorable by nanometer oxides doping to make the system hold high dielectric constant and still satisfy the requirement of EIA X7R specification, attributed to the uniform distribution of nanometer dopants in BaTiO3 grain boundaries and the formation of abundant “core–shell” structure with relatively thinner grain shell. [Copyright &y& Elsevier]

Pb(Zr0.52Ti0.48)O3 (PZT) films have been fabricated on Pt/Ti/SiO2/Si substrates with a new chemical solution deposition technique, in which each layer of PbZrO3 (PZ) and PbTiO3 (PT) was heated to 600°C as soon as it was spin coated. The fabrication of the homogeneous PZT film was finished through the reaction between the PT and PZ layers and without post-annealing. By surveying the variations of the surface micrographs during the deposition process, an island–column hybrid growth mode could be concluded. The low-temperature fabrication brings about enhanced fatigue resistance because of the suppression of the formation of the oxygen vacancies. Measurements of the ferroelectric properties suggest a promising application for the ferroelectric memory devices. [Copyright &y& Elsevier]

SrBi2Ta2O9 (SBT) thin films fabricated by pulsed-laser deposition, on the same substrates and under different deposition conditions, were found showing different textures. The influence of the deposition condition on the texture of the SBT films can be explained by the variations in two aspects. One is the interactions between the plume and the substrate, the other is the composition of the laser-deposited film. The relations between the texture and the ferroelectric property of the films were also discussed. It was found that the ferroelectric properties, such as the polarization and the coercive field, had a strong dependence on the texture of the SBT films. These results are of interest for the fabrication of ferroelectric memories with fatigue-free SBT thin films. [Copyright &y& Elsevier]

Wolframium ions doped SrBi2Ta2O9 ceramics have been synthesized by the conventional mixed-oxide method. A sawtooth-like hysteresis loop was observed at low measuring-frequency. This phenomenon was thought to be related with the perturbation of the defect-dipole polarization under an external electrical field. A developed physical-model was derived on the basis of simplifying such perturbation to a simple harmonic pendulum oscillator, which combines physical considerations with the well-known Preisach model. On the hypothesis of the simple harmonic pendulum oscillator, the included-angle between the defect-dipole polarization and the elementary-dipole polarization can be expressed as the product of the defect-dipole relaxation velocity and permitted relaxation time. Simulation result was excellently agreed with the observed measurement. [Copyright &y& Elsevier]

Rapid polarization switching plays an important role in electron emission from the ferroelectric cathode. Two methods were used in the present paper to support the theory of rapid polarization switching for PLZT samples, namely X-ray diffraction and scanning electron microscopy. The results show that the preferentially oriented domains in the poled samples are disturbed after ferroelectric emission, and a decrease in the 002 peak value and an increase in the 200 peak value were observed after electron emission. [Copyright &y& Elsevier]

Ferroelectric La-modified lead titanate (PLT) thin film were grown on Pt/Ti/SiO2/Si by sputtering the Pb 0.93 La 0.07 TiO 3 targets containing an amounts of excess 8% PbO. The effects of sputtering and annealing conditions on the crystalline structures and the surface morphologies of the PLT thin films have been investigated. The remanent polarization (Pr) and the coercive field of the PLT film through rapid thermal annealing (RTA) was 10.2 μC/cm 2 and 45 kV/cm respectively. The maximum pyroelectric coefficient reached 19 nC/cm 2 .K at 20°C. [ABSTRACT FROM AUTHOR]

Abstract: The influence of Nb on the microstructure and dielectric properties, including temperature dependence of permittivity, dielectric loss, and Curie temperature, has been investigated on Ni-doped BaTiO3 ceramics. Experiments reveal that incorporation of a proper content of Nb in Ni-doped BaTiO3 can control the grain growth, reduce the dielectric loss, shift the Curie temperature to higher temperatures and significantly improve temperature characteristics of the BaTiO3 ceramics. As a result, a novel X8R material is developed in the system, which is very promising for practical use in X8R multi-layer ceramic capacitors (MLCCs). [Copyright &y& Elsevier]

Dielectric capacitors with rapid discharge rates and high power density are the basis for advanced pulsed power systems. Sr 0.7 Bi 0.2 TiO 3 (SBT) is expected to be used in energy storage capacitors owing to the small hysteresis and high energy storage efficiency (η). Nevertheless, the low breakdown strength (BDS) limits the enhancement of energy storage density. This study explores the potential of Ho 2 O 3 -modified SBT to address this limitation. Introducing Ho reduces oxygen vacancies, decreases electrical conductivity, and increases thermal conductivity, thus enhancing BDS. The enhancement mechanism of electrical performance is studied through microscopic morphology analysis, structural refinement and numerical simulation. The Sr 0.7 Bi 0.15 Ho 0.05 TiO 3 exhibits remarkable properties, including ultra-low loss tanδ (0.1 %), ultra-high η (95.8 %), and outstanding thermal, frequency, and cycling stability in energy storage properties. Additionally, Sr 0.7 Bi 0.15 Ho 0.05 TiO 3 possesses a high power density (67.9 MW/cm3) and a rapid discharge rate (0.03 μs). The findings indicate that Sr 0.7 Bi 0.15 Ho 0.05 TiO 3 is a prospective material for energy storage capacitors. [ABSTRACT FROM AUTHOR]

The influence of the TEOS (Si(OC 2 H 5) 4) addition, which decomposes into SiO 2 at high temperature, on the sintering process, morphology, and microwave dielectric properties in Y 3 Al 5 O 12 (YAG) ceramics were investigated in this work. The Y 3 Al 5 O 12 + x wt.% TEOS (0≤ x ≤ 1) ceramics were synthesized through solid-state reaction. The XRD results indicated that all YAG samples possessed a pure cubic garnet structure. The dense, pore-free crystalline microstructure of the specimen was measured by SEM. The Rietveld method was employed to refine the lattice parameters of YAG samples. Results showed that the samples' cellular parameters decreased with increasing amounts of TEOS. The addition of TEOS lowered the sintering temperature and improved the Q × f values of Y 3 Al 5 O 12 ceramics. The YAG system was added by 0.5 wt% TEOS can be exhibited excellent microwave dielectric properties with ε r =10.82, Q × f = 229,423 GHz, τ f = -29.1 ppm/°C sintering at 1670 °C for 12 h. [ABSTRACT FROM AUTHOR]

The La2O3-B2O3-ZnO (LBZ) glass was proved to be an effective sintering aid of the 0.45Ca0.6Nd0.26TiO3-0.55Li0.5Nd0.5TiO3 (CNT-LNT) ceramics. The influence of LBZ glass on the phase composition, low temperature sintering process, microstructure, activation energy, and dielectric properties of CNT-LNT ceramics was investigated in detail. The LBZ glass induced an obvious decrease of the CNT-LNT ceramics sintering temperature from 1350 to 1000 °C due to the liquid phase formation, which reduced the activation energy (Ea) of the CNT-LNT ceramics. In addition, the near zero temperature coefficient of resonant frequency (τƒ) value was obtained by adding moderate quantity of LBZ glass. CNT-LNT + 5 wt% LBZ (CNT-LNT + 5L) ceramics sintered at 1000°C/4 h displayed good microwave dielectric properties of: εr = 101.7, Q × f = 1560 GHz (f = 3.25 GHz) and τƒ = 2.3 ppm °C−1. [ABSTRACT FROM AUTHOR]