Critical Role of Nonrigid Unit and Spiral Acoustical Modes in Designing Colossal Negative Thermal Expansion.

Exploring the relationship between thermal expansion and structural complexity is a challenging topic in the study of modern materials where volume stability is required. This work reports a new family of negative thermal expansion (NTE) materials, AM(CN)4 with A = Li and Na and M = B, Al, Ga, and In. Here, the compounds of LiB(CN)4 and NaB(CN)4 were only synthesized; others were purely computationally studied. A critical role of nonrigid vibrational modes and spiral acoustical modes has been identified in NaB(CN)4. This understanding has been exploited to design the colossal NTE materials of NaM(CN)4 (M = Al, Ga, In). A joint study involving synchrotron X-ray diffraction, Raman spectroscopy, and first-principles calculations has been conducted to investigate the thermal expansion mechanism. It has been found that the A atoms can either increase the symmetry of the crystal structure, inducing stronger NTE, or lower the crystal symmetry, thus resulting in positive thermal expansion. Conversely, the M-site atoms do not affect the crystal structure. However, as the radius of the M atoms increases, the ionic nature of the C-M bonds strengthens and the CN vibrations become more flexible, thereby enhancing the NTE behavior. This study provides new insights to aid in the discovery and design of novel NTE materials and the control of thermal expansion.

Negative Thermal Expansion in ABC(MoO4)3 Compounds.

Negative thermal expansion (NTE) compounds provide a solution for the mismatch of coefficients of thermal expansion in highly integrated device design. However, the current NTE compounds are rare, and how to effectively design new NTE compounds is still challenging. Here, a new concept is proposed to design NTE compounds, that is, to increase the flexibility of framework structure by expanding the space in framework structure compounds. Taking the parent compound NaZr2(PO4)3 as a case, a new NTE system AIBIICIII(MoO4)3 (A = Li, Na, K, and Rb; B = Mg and Mn; C = Sc, In, and Lu) is designed. In these compounds, the large volume of MoO4 tetrahedron is used to replace the small volume of PO4 tetrahedron in NaZr2(PO4)3 to enhance structural space and NTE performance. Simultaneously, a joint study of temperature-dependent X-ray diffraction, Raman spectroscopy, and the first principles calculation reveals that the NTE in AIBIICIII(MoO4)3 series compounds arise from the coupled oscillation of polyhedral. Large-radius ions are conducive to enhancing the space and softening the framework structure to achieve the enhancement of NTE. The current strategy for designing NTE compounds is expected to be adopted in other compounds to obtain more NTE compounds.

Antithermal Quenching Upconversion Luminescence via Suppressed Multiphonon Relaxation in Positive/Negative Thermal Expansion Core/Shell NaYF4:Yb/Ho@ScF3 Nanoparticles.

Thermal quenching (TQ) has been naturally entangling with luminescence since its discovery, and lattice vibration, which is characterized as multiphonon relaxation (MPR), plays a critical role. Considering that MPR may be suppressed under exterior pressure, we have designed a core/shell upconversion luminescence (UCL) system of α-NaYF4:Yb/Ln@ScF3 (Ln = Ho, Er, and Tm) with positive/negative thermal expansion behavior so that positive thermal expansion of the core will be restrained by negative thermal expansion of the shell when heated. This imposed pressure on the crystal lattice of the core suppresses MPR, reduces the amount of energy depleted by TQ, and eventually saves more energy for luminescing, so that anti-TQ or even thermally enhanced UCL is obtained.

Giant Negative Thermal Expansion in Ultralight NaB(CN)4.

Negative thermal expansion (NTE) is crucial for controlling the thermomechanical properties of functional materials, albeit being relatively rare. This study reports a giant NTE (αV ∼-9.2 ⋅ 10-5  K-1 , 100-200 K; αV ∼-3.7 ⋅ 10-5  K-1 , 200-650 K) observed in NaB(CN)4 , showcasing interesting ultralight properties. A comprehensive investigation involving synchrotron X-ray diffraction, Raman spectroscopy, and first-principles calculations has been conducted to explore the thermal expansion mechanism. The findings indicate that the low-frequency phonon modes play a primary role in NTE, and non-rigid vibration modes with most negative Grüneisen parameters are the key contributing factor to the giant NTE observed in NaB(CN)4 . This work presents a new material with giant NTE and ultralight mass density, providing insights for the understanding and design of novel NTE materials.

The formation energy, phase transition, and negative thermal expansion of Fe2-xScxW3O12.

Tungstates with a molecular formula A2W3O12 exhibits a wider negative thermal expansion (NTE) temperature range than molybdates but are challenging to synthesize, especially when A = Fe or Cr with metastable structures. To enhance the structural stability of Fe2W3O12, Sc with lower electronegativity is adopted to substitute Fe according to Fe2-xScxW3O12, considering the thermodynamic stability of Sc2W3O12. It is shown that the solid solutions can be easily synthesized and the phase transition temperature (PTT) can be tuned to well below room temperature (RT). Theoretical calculations and experimental results show that the formation energy decreases and the W-O bond in Fe-O-W gradually strengthens as the substitution of Sc in Fe2-xScxW3O12 increases, indicating an increase in structural stability. NTE is enhanced after phase transition with an increase in the Sc content. The reduction in PTT and the enhancement in NTE properties of Fe2W3O12 could result in a decrease in the effective electronegativity of the Fe-site elements, resulting in a low formation energy and strengthened W-O bond in Fe-O-W, which corresponds to a more stable structure.

The influence of adjunctive traditional Chinese medicine therapy on survival in primary liver cancer: a real-world study based on electronic medical records.

Background: Traditional Chinese medicine (TCM) effectively improves the survival rate and quality of life of primary liver cancer patients, but high-level evidence is lacking. Patients and methods: Patients were selected from 5 tertiary hospitals in Henan Province, China. Two thousand sixty-seven patients with primary liver cancer were included in the study. The electronic medical records (EMRs) of the patients were collected. Patients who received adjunctive TCM treatment and underwent treatment cumulative time for more than 1 month were classified as the TCM intervention cohort. Patients who did not receive adjunctive TCM treatment or underwent treatment cumulative time for less than 1 month were classified as the non-TCM intervention cohort. The main outcome indicators were the survival rate and overall survival time. The propensity score inverse probability weighting method was used to balance the differences between the groups. Results: The primary cohort comprised 2,067 patients, including 462 patients who received adjunctive TCM treatment and 1,605 patients who did not receive adjunctive TCM treatment. The results of the Kaplan‒Meier survival curve indicated that the survival rate and median survival time of the exposure group before and after propensity score weighting were greater than those of the control group (p < 0.0001). Univariate Cox regression analysis after propensity score weighting showed that adjunctive TCM treatment was an independent protective factor for survival [regression coefficient = -0.215, hazard ratio (HR) = 0.8066, 95% confidence interval (CI) (0.6609-0.9844)]. Conclusion: Adjuvant treatment with TCM has a protective effect on the prognosis of patients with primary liver cancer; it can reduce the mortality and prolong the survival time.

Influence of A/B Element Substitution on Negative Thermal Expansion in AB(CN)6 (A = Al, Ga, In; B = Co, Fe, Mn, Cr, V, Ti): A Density Functional Theory Study.

Negative thermal expansion as an abnormal physical behavior of materials has promising applications in a high sophisticated equipment field, but the materials are rare. Here, we use the first-principles calculations based on density functional theory combined with the recently developed average atomic volume (AAV = V/N, where V is unit cell volume and N is the number of atoms in the unit) rule to predict the large isotropic negative thermal expansion materials of Prussian blue analogues AB(CN)6 (A = Al, Ga, In; B = Co, Fe, Mn, Cr, V, Ti) in a wide temperature range. Our results clearly show that the coefficient of negative thermal expansion has a near-linear relationship with the average atomic volume of the systems and is also influenced by the element substitution at the A or B site. Lattice dynamic simulations indicate that the main contribution to the negative thermal expansion comes from the low-frequency transverse vibration of the (B)-C≡N-(A) groups, especially the transverse vibration of the N atoms. Thus, the element substitution at the A site (binding to N) can tune the negative thermal expansion behavior of the systems more effectively than that at the B site (binding to C), indicating the different roles of bonds on the negative thermal expansion. Our present work not only expands the kinds of isotropic materials but also gives some insights into the relationship between the average atomic volume and negative thermal expansion.

Control of Thermal Expansion in TaVO5 by Double Chemical Substitution.

The control of thermal expansion is an important and challenging issue. Focusing attention on the class of AMO5 negative thermal expansion (NTE) materials, an approach to control their thermal expansion is still missing. In this work, the thermal expansion of TaVO5 has been controlled from strong negative to zero to positive by double chemical substitution, i.e., Ti and Mo replace Ta and V elements, respectively. A joint study of temperature-dependent X-ray diffraction, X-ray photoelectron spectroscopy, and first-principles calculations has been performed to investigate the thermal expansion mechanism. With the increasing substitution of Ti and Mo atoms, the valence state always remains balanced, and the volume decreases together with a lattice distortion, which leads to the suppression of the NTE. Lattice dynamics calculations confirm that the negative Grüneisen parameters of the low-frequency modes weaken and the thermal vibrations of the polyhedral units diminish after the substitution of Ti and Mo atoms. The present work successfully achieves a tailored thermal expansion in TaVO5 and draws a possible way to control the thermal expansion of other NTE materials.

Liujunzi decoction exerts potent antitumor activity in oesophageal squamous cell carcinoma by inhibiting miR-34a/STAT3/IL-6R feedback loop, and modifies antitumor immunity.

BACKGROUND: Liujunzi decoction (LJZD), a traditional herbal formula and one of the most commonly used adjuvant medications for the treatment of oesophageal squamous cell carcinoma (ESCC), exerts good antitumor and immunomodulatory activity. However, its specific mechanism of action remains largely unclear. PURPOSE: In order to examine the potential primary and adjuvant antitumor mechanisms of LJZD, both in vitro and in vivo. METHODS: IL-6 and miR-34a inhibitors were used to activate the miR-34a/STAT3/IL-6R feedback loop to observe the effects of LJZD. A humanised mouse model with a functional human immune system was constructed to evaluate the antitumor efficacy of LJZD in vivo on xenograft tumours, which was compared to that of the positive control drug anti-PD-1 monoclonal antibodies (mAb). Finally, a co-culture system of peripheral blood mononuclear and tumour cells in vitro was used to analyse the cytotoxic activity of LJZD on T cells. RESULTS: LJZD significantly interfered with IL-6-induced activation of the miR-34a/STAT3/IL-6R feedback loop in ESCC by restoring the expression of the tumour suppressor miR-34a, and inhibited the proliferation of EC109 oesophageal cancer cells in a dose-dependant manner. Furthermore, LJZD effectively suppressed oesophageal tumour growth in vivo and alleviated organ injury and visceral index. Furthermore, LJZD boosted antitumor immunity by increasing IFN-γ expression and CD8+tumour-infiltrating lymphocytes (TILs) infiltration in the peripheral blood and tumour tissues, respectively, which may be related to a decrease in PD-1, but not PD-L1 expression. Finally, we confirmed that LJZD strengthens the killing ability of T cells by suppressing PD-1 expression in a co-culture system in vitro. CONCLUSION: LJZD exerts excellent antitumor effect by interfering with the miR-34a/STAT3/IL-6R feedback loop and augmenting antitumor immune responses. Which provides new insights into mechanisms for LJZD and sheds light on the multifaceted role of phytomedicine in cancer.

Insight into the Relationship between Negative Thermal Expansion and Structure Flexibility: The Case of Zn(CN)2-Type Compounds.

High structure flexibility can lead to large negative thermal expansion (NTE), but the reason is not clear. In this work, first-principles calculations have been carried out to investigate the relationship between NTE and structure flexibility in Zn(CN)2-type compounds. Smaller bulk modulus corresponds to larger compressibility, thus making the crystal structure more flexible and more suitable for NTE. It indicated that the ionic nature of the bond and the bond length jointly affect the structural flexibility and then act on the transverse vibration of C and N atoms. The results of lattice dynamic suggested that higher structural flexibility promotes a greater number of low-frequency optical modes with negative Grüneisen parameters, resulting in a larger NTE. This work also gives us new insight into the design of NTE materials.

Understanding Large Negative Thermal Expansion of NdFe(CN)6 through the Electronic Structure and Lattice Dynamics.

A large negative thermal expansion (NTE) (αv = -4.1 × 10-5 K-1, 100-525 K) has been discovered in NdFe(CN)6. Here, the synchrotron X-ray diffraction and lattice dynamics calculations using the density functional theory were conducted to understand the NTE in NdFe(CN)6. The information obtained on the bond nature of the Nd-N≡C-Fe linkage and on the atomic thermal vibrations suggests that the transverse vibrations of the -N≡C- group, in particular from N atoms, produced the NTE in NdFe(CN)6. This is corroborated by the calculated Grüneisen parameters, which confirm the relationship between NTE and CN atomic vibrations. The results provide a helpful contribution toward the realization of new materials with negative or controllable thermal expansion.

[Polysaccharide of Atractylodis Macrocephalae Rhizoma inhibits expression of immune checkpoint PD-L1 by targeting miR-34a in esophageal carcinoma cells].

The immune checkpoint programmed cell death-ligand 1(PD-L1)-mediated immunosuppression is among the important features of tumor. PD-L1, an immunosuppressant, can induce T cell failure by binding to programmed cell death-1(PD-1). Thus, the key to restoring the function of T cells is inhibiting the expression of PD-L1. The Chinese medicinal Atractylodis Macrocephalae Rhizoma(AMR) has the anti-tumor, anti-inflammatory, antioxidant, and hypoglycemic activities, and the polysaccharide in AMR(PAMR) plays a crucial role in immunoregulation, but the influence on the immune checkpoints which are closely related to immunosuppression has not been reported. MicroRNA-34 a(miR-34 a) expression in esophageal carcinoma tissue is significantly lower than that in normal tissue. This study aims to investigate the inhibitory effect of PAMR on esophageal carcinoma cells, and the relationship between its inhibitory effect on PD-L1 expression and miR-34 a, which is expected to clarify the anti-tumor mechanism of PAMR. Firstly, different human esophageal carcinoma cell lines(EC9706, EC-1, TE-1, EC109 cells) were screend out, and expression of PD-L1 was determined. Then, EC109 cells, with high expression of PD-L1, were selected for further experiment. The result showed that PAMR suppressed EC109 cell growth. According to the real-time quantitative PCR(qPCR) and Western blot, it significantly suppressed the mRNA and protein expression of PD-L1, while promoting the expression of tumor suppressor miR-34 a. The confocal microscopy and luci-ferase assay proved that PAMR alleviated the inhibitory effect of PD-L1 while blocked miR-34 a. Additionally, the expression of PD-L1 was controlled by miR-34 a, and the combination of miR-34 a inhibitor with high-dose PAMR reversed the inhibitory effect of PAMR on PD-L1 protein expression. Thus, the PAMR may inhibit PD-L1 by increasing the expression of miR-34 a and regulating its downstream target genes. In conclusion, PAMR inhibits the expression of PD-L1 mainly by inducing miR-34 a.

A linear scaling law for predicting phase transition temperature via averaged effective electronegativity derived from A2M3O12-based compounds.

The chemical flexibility of A2M3O12-based compounds enables the design of materials with versatile functionalities such as ferroelastic switching, ion conduction and negative thermal expansion (NTE) above the ferroelastic transition temperature (Tt), which is promising for a variety of applications. Quantitative prediction of Tt is essential but lacking. Herein we propose a concept of averaged effective electronegativity (AEE) and establish a linear relationship between the Tt and AEE for A2M3O12-based compounds. The linear scaling law is validated using first principles calculations of the effective charge on oxygen and its effectiveness is verified experimentally by designing high entropy compounds Scx1Zrx2Hfx3Fex4Moy1Vy2O12 and a NTE compound Zr2MoVPO12 with expected Tt. Generalization of the linear scaling law to other NTE oxides with displacive phase transition is also demonstrated. The findings can be used as a simple and effective approach to guide the design of novel compounds with desired properties and Tt.

The Scavenger Receptor MARCO Expressed by Tumor-Associated Macrophages Are Highly Associated With Poor Pancreatic Cancer Prognosis.

Macrophage-targeting therapies have become attractive strategies for immunotherapy. Deficiency of MARCO significantly inhibits tumor progression and metastasis in murine models of pancreatic cancer. However, the role of MARCO in patients with pancreatic cancer remains unclear. In the present study, we analyzed tumor-associated macrophage (TAM)-related changes using the Cancer Genome Atlas database. We observed a significant enrichment of M2 macrophages in pancreatic cancer tissues. We found that several pro-tumor markers are increased in cancer tissues, including CD163, CD206, SIRPα, LILRB1, SIGLEC10, AXL, MERTK, and MARCO. Crucially, MARCO is highly or exclusively expressed in pancreatic cancer across many types of solid tumors, suggesting its significant role in pancreatic cancer. Next, we investigated the expression of MARCO in relation to the macrophage marker CD163 in a treatment-naïve pancreatic cancer cohort after surgery (n = 65). MARCO and CD163 were analyzed using immunohistochemistry. We observed increased expression of CD163 and MARCO in pancreatic cancer tissues compared with paracancerous tissues. Furthermore, we observed a large variation in CD163 and MARCO expression in pancreatic cancer tissues among cases, suggesting the heterogeneous expression of these two markers among patients. Correlation to clinical data indicated a strong trend toward worse survival for patients with high CD163 and MARCO macrophage infiltration. Moreover, high CD163 and MARCO expression negatively affected the disease-free survival and overall survival rates of patients with pancreatic cancer. Univariate and multivariate analysis revealed that CD163 and MARCO expression was an independent indicator of pancreatic cancer prognosis. In conclusion, high CD163 and MARCO expression in cancer tissues is a negative prognostic marker for pancreatic cancer after surgery. Furthermore, anti-MARCO may be a novel therapy that is worth studying in depth.

Anomalous Thermal Expansion in Ta2WO8 Oxide Semiconductor over a Wide Temperature Range.

Expansion of material is one of the major impediments in the high precision instrument and engineering field. Low/zero thermal expansion compounds have drawn great attention because of their important scientific significance and enormous application value. However, the realization of low thermal expansion over a wide temperature range is still scarce. In this study, a low thermal expansion over a wide temperature range has been observed in the Ta2WO8 oxide semiconductor. It is a balance effect of the negative thermal expansion of the a axis and the positive thermal expansion of the b axis and the c axis to achieve low thermal expansion behavior. The results of the means of variable temperature X-ray diffraction and variable pressure Raman spectroscopy analysis indicated that the transverse vibration of bridging oxygen atoms is the driving force, which is corresponding to the low-frequency lattice modes with a negative Grüneisen parameter. The present study provides one wide band gap semiconductor Ta2WO8 with anomalous thermal expansion behavior.

Size and crystal symmetry breaking effects on negative thermal expansion in ScF3 nanostructures.

Nowadays, one of the most typical and important potential applications of negative thermal expansion (NTE) materials is to prepare zero thermal expansion or controllable coefficient thermal expansion materials by compounding them with positive thermal expansion materials. The research on NTE properties at the nanoscales is the basis and premise for the realization of high-quality composites. Here, using first-principles calculations, we take a typical open framework material ScF3 as an example to study a new NTE mechanism at the nanoscale, which involves edge and size effects, as well as crystal symmetry breaking. By analyzing the vibrational modes in ultrathin ScF3 films, three effects contributing to the NTE properties are identified, namely, the acoustic mode (ZA mode) induced by surface truncation, the enhanced rotations of ScF6 octahedra in the surface layer and the suppressed rotations of ScF6 octahedra in the inner layer due to crystal symmetry breaking. With increasing thickness, the effect of the ZA mode vibration gradually weakens, while the rotations of the ScF6 octahedra in the surface and inner layers are enhanced. Ultimately, the approximately mutual compensation of these three effects makes the NTE coefficients of different thicknesses almost unchanged. Finally, we simply generalize our conclusions to zero dimensional nanoparticles. This work reveals a new NTE mechanism in low-dimensional open framework materials, which serves as a guide in designing NTE materials at the nanoscale.

Toosendanin Shows Potent Efficacy Against Human Ovarian Cancer through Caspase-Dependent Mitochondrial Apoptotic Pathway.

Toosendanin (TSN) is a triterpenoid extracted from the bark or fruits of Melia toosendan Sieb et Zucc, which is a traditional Chinese medicine and mainly grows in China and India. TSN has been verified to possess antitumor activities on various human cancers, whereas the effects of TSN on ovarian cancer (OC) has not been reported yet. Here, TSN was shown to significantly inhibit proliferation of SKOV3 and OVCAR3 cell lines in a dose- and time-dependent manner. Treatment of OC cells with TSN resulted in colony formation reduction, S and G2/M phase arrest, cell apoptosis, and dramatic decrease in mitochondrial membrane potential. Furthermore, TSN suppressed invasion and migration of OC cells. Research on molecular mechanism indicated that the above efficacy of TSN was associated with decreased expression of survivin, PARP-1, Bcl-2, Bcl-xl, caspase-3, caspase-9, MMP-2 and MMP-9 and increased expression of cleaved PARP-1, Bax, cleaved caspase-3 and cleaved caspase-9. Finally, in vivo results showed that TSN suppressed OC xenograft tumor growth by inducing apoptosis and regulating the related protein expression levels of SKOV3 cells in transplanted tumors. Taken together, our data provide new insights into TSN as a potentially effective reagent against human OC through caspase-dependent mitochondrial apoptotic pathway.

Understanding Negative Thermal Expansion of Zn2GeO4 through Local Structure and Vibrational Dynamics.

Zn2GeO4 is a multifunctional material whose intrinsic thermal expansion properties below ambient temperature have not been explored until now. Herein, the thermal expansion of Zn2GeO4 is investigated by synchrotron X-ray diffraction, with the finding that Zn2GeO4 exhibits very low negative (αv = -2.02 × 10-6 K-1, 100-300 K) and positive (αv = +2.54 × 10-6 K-1, 300-475 K) thermal expansion below and above room temperature, respectively. A combined study of neutron powder diffraction and extended X-ray absorption fine structure spectroscopy shows that the negative thermal expansion (NTE) of Zn2GeO4 originates from the transverse vibrations of O atoms in the four- and six-membered rings with ZnO4-GeO4 tetrahedra. In addition, the results of temperature- and pressure-dependent Raman spectra identify the low-frequency phonon modes (50-150 cm-1) with negative Grüneisen parameters softening upon pressuring and stiffening upon heating during the lattice contraction, thus contributing to the NTE. This study not only reports the interesting thermal expansion behavior of Zn2GeO4 but also provides further insights into the NTE mechanism of novel structures.

Zero Thermal Expansion in Ta2Mo2O11 by Compensation Effects.

Although zero thermal expansion (ZTE) materials have broad application prospects for high precision engineering, they are rare. Here, a new ZTE material, Ta2Mo2O11 (αl = 0.37 × 10-6 K-1, 200-600 K), is reported. A joint study of high-resolution synchrotron X-ray diffraction, temperature- and pressure-dependent Raman spectroscopy, and first-principles calculations was performed to investigate the structure and dynamics of Ta2Mo2O11 with the aim of understanding its ZTE mechanism. Ta2Mo2O11 displays a layered structure, stacking along the [001] direction. Analysis of the phonon modes indicates that positive and negative contributions to thermal expansion are balanced, and a shrinkage occurs along the layers, while the interlayer distance expands with increasing temperature, thus giving rise to the ZTE behavior of Ta2Mo2O11. The present study provides a promising ZTE material and new insights into the mechanisms of thermal expansion.

Effect of H2O Molecules on Thermal Expansion of TiCo(CN)6.

Understanding the role of guest molecules in the lattice void of open-framework structures is vital for tailoring thermal expansion. Here, we take a new negative thermal expansion (NTE) compound, TiCo(CN)6, as a case study from the local structure perspective to investigate the effect of H2O molecules on thermal expansion. The in situ synchrotron X-ray diffraction results showed that the as-prepared TiCo(CN)6·2H2O has near-zero thermal expansion behavior (100-300 K), while TiCo(CN)6 without water in the lattice void exhibits a linear NTE (αl = -4.05 × 10-6 K-1, 100-475 K). Combined with the results of extended X-ray absorption fine structure, it was found that the intercalation of H2O molecules has the clear effect of inhibiting transverse thermal vibrations of Ti-N bonds, while the effect on the Co-C bonds is negligible. The present work displays the inhibition mechanism of H2O molecules on thermal expansion of TiCo(CN)6, which also provides insight into the thermal expansion control of other NTE compounds with open-framework structures.