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This work aims to provide a thorough analysis of the phase transition dynamics in lead-free Bi0.5Na0.5TiO3 by in situ Raman spectroscopy, which is conducted under varying temperature and electric field. All the transition points are proved by the Raman response of phonon vibration, including the depolarization temperature at ∼200 °C, potential transition at ∼280 °C, Curie temperature at ∼320 °C and tetragonal-cubic transition above ∼500 °C. The vibration of A-site ions primarily contributes to the depolarization behavior, which is also responsible for the strong polarity in Bi0.5Na0.5TiO3. The transitions at ∼280 °C and ∼320 °C are confirmed by the phonon vibrations of the Ti–O bonds and the TiO6 octahedra. Meanwhile, the distortion of the Ti–O bonds and TiO6 octahedra under an electric field results in weak polarity. The thermal hysteresis behavior is related to the dynamics of phonon thermal evolution, because of the delayed response of the vibration mode to thermal activation of Ti–O bonds and TiO6 octahedra. The results lay a foundation for understanding the mechanism of the phase transition and polarization in Bi0.5Na0.5TiO3, guiding the design of functional devices for electromechanical applications. [ABSTRACT FROM AUTHOR]

A novel printed antenna having a frequency band notched function for UWB application is proposed and studied. With a pair of inverted-F-shaped slots introduced around the microstrip line on the ground and inserting a semicircle-rectangle radiating element, the designed antenna satisfies the VSWR requirement of less than 2.0 in the frequency band between 2.9 GHz–11.15 GHz while showing the band rejection performance in the frequency band from 4.96 GHz to 6.03 GHz. The experiment results and characteristics of the proposed antenna are shown in this paper. [ABSTRACT FROM AUTHOR]

A frequency notched ultra-wideband planar slot antenna is presented. By introducing a modified fractal-shaped slot to the patch, a notched band within a wide operation bandwidth is achieved. The designed antenna satisfies the voltage standing wave ratio requirement of less than 2.0 in the frequency band from 3.01 to 13 GHz above while showing the band rejection performance about 500 MHz in the frequency band of 5.59 to 6.09 GHz. Simulation and measurement results are presented for the proposed antenna. [ABSTRACT FROM AUTHOR]

A novel printed antenna having a frequency band-notched function for UWB applications is proposed and studied. With a pair of inverted C-shaped slots introduced around the microstrip line on the ground, a frequency-notched response at 5.2 GHz is obtained. The designed antenna satisfies the VSWR requirement of less than 2.0 in the frequency band between 2.8 and 10.7 GHz while showing the band rejection performance in the frequency band from 4.8 to 5.7 GHz. Good monopole-like radiation patterns and antenna gains have also been obtained. [ABSTRACT FROM AUTHOR]

In this paper, we propose a novel printed wideband monopole antenna with simple structure and compact size. The proposed antenna can provide two separate impedance bandwidths of 1.55 GHz about 48.8% (from 2.4 to 3.95 GHz) and 1.275 GHz about 22.4% (from 5.05 to 6.325 GHz), making it easily cover the required bandwidths for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) operations. Also, good antenna performances such as radiation patterns and antenna gains over the operating bands have been observed. Details of the proposed antenna design and experimental results are presented and discussed. [ABSTRACT FROM AUTHOR]

A new welding method called 'keyhole mode variable polarity plasma arc weld bonding' (keyhole mode VPPAWB) was presented to join Mg alloy. It was put forward as a hybrid of the keyhole mode variable polarity plasma arc welding (keyhole mode VPPAW) and the adhesive bonding process. The characteristic of the keyhole mode VPPAWB technique was discussed. After welding, the microstructures and mechanical properties of joint were investigated. The results showed that a lap joint without pores and inclusions could be obtained by the keyhole mode VPPAWB process. Keyhole mode and variable polarity power were helpful to obtain a free defect joint. The fusion zone of joint consisted of refined isometric crystal, and the grain was finer in the upper fusion zone than that in the bottom. Compared with keyhole mode VPPAW joint and adhesive bonding joint, the keyhole mode VPPAWB joint exhibited a better failure load. [ABSTRACT FROM AUTHOR]

A small printed antenna is described with subband rejection for ultrawideband (UWB) applications [1]. Two notches are incorporated in the radiating structure of the antenna to act as a bandstop filter to reject the undesired subband within the whole bandwidth [2]. The designed antenna features a compact size of 26×25 mm2, and satisfies the VSWR requirement of less than 2.0 in the frequency band from 3 GHz to more than 12 GHz excluding any undesired subband such as 4.65–5.65 GHz. Good monopole-like radiation patterns and antenna gains have also been obtained. [ABSTRACT FROM AUTHOR]

A novel printed wideband monopole antenna for multiband operations is presented. Good impedance matching in a wide dual-band can be achieved by a simple circular monopole and a rectangular conductor-backed plane with a square hole. The measured 10 dB bandwidth for return loss is from 1.78 to 4.19 GHz about 80% and 5.12 to 6.35 GHz about 21.4% which covering all the 2.4/5.2/5.8 GHz WLAN, 2.5/3.5/5.5 GHz WiMAX, DCS (1710–1880 MHz), PCS (1850–1990 MHz), UMT (1920–2170 MHz), and IMT-2000 (1900–2025 MHz) bands applications. Peak antenna gains have been obtained about 3.39 and 3.96 dBi for the lower and upper bands, respectively. [ABSTRACT FROM AUTHOR]

Two-dimensional isothermal airflows in a 1/4-scale ventilated model room were numerically investigated using different turbulence models that range from the zero-equation model to the Reynolds stress model (RSM). Quantitative and qualitative comparisons were made between the numerical results and corresponding experimental data with the purpose of evaluating the performance of different turbulence models. Also investigated were the effects of the inlet boundary conditions, three-dimensional effects, and wall treatments on the numerical predictions. The results showed that all the turbulence models used in this study could capture the general flow behavior observed in the experiments, but certain differences existed in the flow patterns between the numerical predications and the experimental observations. The predicted mean velocities were closer to the measurements than the predicted turbulent kinetic energy. It was found that some turbulence models performed better in predicting mean velocities, while other models did better in predicting turbulent kinetic energy. This study shows that the selection of turbulence models should depend on the quantities being examined. [ABSTRACT FROM AUTHOR]

A novel trident-shaped dual-band CPW-fed monopole antenna for PCS/WLAN applications is presented. By inserting two pairs of symmetrical strips in the middle strip of the trident-shaped antenna, dual-frequency operating bands with 10 dB return-loss bandwidths of 33.7%, ranging from 1.80 to 2.53 GHz, and of about 1100 MHz centred at 5.5 GHz have been achieved. They cover the required bandwidths of the PCS band (1.85-1.99 GHz) and WLAN bands (2.4-2.484 and 5.15-5.825 GHz). Also, good radiation patterns, and 3.6 and 9.1 dBi peak antenna gains for the lower (2.2 GHz) and upper (5.5 GHz) bands have been measured. [ABSTRACT FROM AUTHOR]

Background: Femoral neck system (FNS) is a new type of internal fixation system which has been widely used for treating femoral neck fractures (FNFs).Compared with other internal fixation methods, FNS is minimally invasive and stable, and often achieves satisfactory short-term efficacy.Early failure of FNS (EFFNS) is not uncommon, however, there are few literatures and reports on factors associated with EFFNS.This study aimed to survey the prevalence and risk factors of EFFNS., Methods: We retrospectively analysed 62 patients with FNFs and underwent FNS fixation between 2019 and 2021. Demographic data, clinical characteristics, radiographic features and treatment process were described. Multifactor logistic regression analysis was used to analyse the different influencing factors., Results: Out of the 62 FNFs patients, 10 patients (16.1%) developed EFFNS, including 6 cases of severe femoral neck shortening, 2 cases of screw-out, 1 case of avascular necrosis of the femoral head and 1 case of nonunion. In the failure group, all patients were younger than 65 years old, which was significantly higher than 59.6% in the healing group (P = 0.012). There were no significant differences in sex(P = 0.490), BMI (P = 0.709), injured side (P = 0.312), injury mechanism (P = 0.617), reduction method(P = 0.570),femoral neck-shaft angle(P = 0.545), Pauwels classification (P = 0.564) and Garden classification (P = 0.195). Moreover, we not found that Garden classification (P = 0.464) and age (P = 0.128) were statistically significant risk factors for EFFNS at multivariate analysis., Conclusion: In this study, sex, BMI, injury side, injury mechanism, reduction method, Pauwels angle, femoral neck-shift angle, Pauwels classification and Garden classification were excluded as EFFNS risk factors. Moreover, our study demonstrated that age and Garden classification were not significant risk factors at multivariate analysis., Trial Registration: ChiCTR, ChiCTR2100051360. Registered on 21 September, 2021. https://www.chictr.org.cn/index.aspx ., (© 2023. The Author(s).)

In this study we compared the effect of postexposure treatment of the acyclic nucleoside analogs 9-(2-phosphonylmethoxyethyl)-adenine (PMEA) and 9-(2-phosphonylmethoxypropyl)-adenine (PMPA) on the kinetics of viral load in the blood and lymph nodes of rhesus macaques chronically infected with SIVmac251 for 18 weeks. Two of the four macaques treated with PMPA (20 mg/kg per day) for 28 consecutive days had demonstrable reductions in viral loads of 1.5 and 3 logs. Three of four macaques given the same dosing regimen of PMEA had viral load reductions ranging from 1.25 to 2.8 logs. Furthermore, treatment with either drug caused a reduction in virus burden in the lymph nodes by 2 weeks posttreatment. However, in both PMEA- and PMPA-treated animals, viral loads rebounded to day of treatment levels by 2 weeks after termination of treatment. The extent to which viral load was suppressed was similar for both drugs. In contrast, viral loads in three of four mock-treated animals remained persistently high throughout the study. This study has demonstrated that postexposure treatment with these acyclic nucleoside analogs could modulate the kinetics of viral load reduction in some animals.

Two live attenuated single-deletion mutant simian immunodeficiency virus (SIV) constructs, SIV239Deltanef and SIVPBj6.6Deltanef, were tested for their abilities to stimulate protective immunity in macaques. During the immunization period the animals were examined for specific immune responses and virus growth. Each construct generated high levels of specific immunity in all of the immunized animals. The SIV239Deltanef construct was found to grow to high levels in all immunized animals, with some animals remaining positive for virus isolation and plasma RNA throughout the immunization period. The SIVPBj6.6Deltanef was effectively controlled by all of the immunized animals, with virus mostly isolated only during the first few months following immunization and plasma RNA never detected. Following an extended period of immunization of over 80 weeks, the animals were challenged with a pathogenic simian-human immunodeficiency virus (SHIV) isolate, SIV89. 6PD, by intravenous injection. All of the SIV239Deltanef-immunized animals became infected with the SHIV isolate; two of five animals eventually controlled the challenge and three of five animals, which failed to check the immunizing virus, progressed to disease state before the unvaccinated controls. One of five animals immunized with SIVPBj6.6Deltanef totally resisted infection by the challenge virus, while three others limited its growth and the remaining animal became persistently infected and eventually died of a pulmonary thrombus. These data indicate that vaccination with attenuated SIV can protect macaques from disease and in some cases from infection by a divergent SHIV. However, if animals are unable to control the immunizing virus, potential damage that can accelerate the disease course of a pathogenic challenge virus may occur.

Balanol is a potent protein kinase C (PKC) inhibitor that is structurally composed of a benzophenone diacid, a 4-hydroxybenzamide, and a perhydroazepine ring. A number of balanol analogs in which the perhydroazepine moiety is replaced have been synthesized and their biological activities evaluated against both PKC and cAMP-dependent kinase (PKA). The results suggested that the activity and the isozyme/kinase selectivity of these compounds are largely related to the conformation about this nonaromatic structural element of the molecules.

The oligomeric stilbenes (+)-alpha-viniferin (1), miyabenol C (2), and kobophenol A (3) have been isolated from Caragana sinica (Buchoz) Rehd (Leguminosae). (+)-alpha-Viniferin (1) and miyabenol C (2) exhibited protein kinase C inhibitory activity at low micromolar concentrations. (+)-alpha-Viniferin inhibited keratinocyte proliferation (0.4 microM) and free radical release in whole blood (47 microM), in vitro, and may be useful in treating hyperproliferative or inflammatory skin diseases.

Tumor growth is dependent upon angiogenesis. There is an intense search for pharmacological inhibitors of angiogenesis as a novel approach to treat angiogenic diseases, e.g., arthritis, diabetic retinopathy or cancer. A series of compounds, originally studied as potential protein kinase C inhibitors, included the diaminoanthraquinone NSC 639366 (1-[[3-(diethylamino)-2-hydroxypropyl]amino]-4-[(2,3- epoxypropyl)amino]-9,10-anthracenedione fumaric acid salt) (SPC-100097), was found to reversibly inhibit bovine endothelial cell growth with an IC50 that ranged between 1 and 4 nM. NSC 639366 reversibly inhibited endothelial cell migration, particularly endothelial cells stimulated by the potent angiogenic molecule, basic fibroblast growth factor. The activity of secreted urokinase-type plasminogen activator and active interstitial collagenase, but not gelatinase, was inhibited by NSC 639366. In vivo, angiogenesis was significantly inhibited by NSC 639366 by using the chick chorioallantoic membrane or the rat corneal bioassay. Two analogs of NSC 639366 did not inhibit endothelial cell growth. These experiments introduce a novel compound that could be clinically useful against angiogenic diseases and encourage further development of compounds that inhibit the plasminogen-plasmin system known to be a key regulator of angiogenesis.

Betulinic acid [1] and platanic acid [2], isolated from the leaves of Syzigium claviforum, were found to be inhibitors of HIV replication in H9 lymphocyte cells. Evaluation of anti-HIV activity with eight derivatives of 1 revealed that dihydrobetulinic acid [3] was also a potent inhibitor of HIV replication. The C-3 hydroxy group and C-17 carboxylic acid group, as well as the C-19 substituents, contribute to enhanced anti-HIV activity. The inhibitory activity of these compounds against protein kinase C (PKC) was also examined, since a correlation between anti-HIV and anti-PKC activities has been suggested. However, there was no apparent correlation between anti-HIV activity and the inhibition of PKC among these compounds.

We have previously shown that some ellagitannins are potent inhibitors of protein kinase C (PKC). On the basis of this finding, several series of hexahydroxybiphenyl derivatives of ellagic acid were synthesized as simple analogs of these ellagitannins and were evaluated for their inhibitory effect against PKC. Compounds 23 and 26 were found to be potent inhibitors of PKC, while hexakis-(benzyloxy)biphenyl derivatives exhibited weak anti-PKC activity.

We have synthesized a promising class of bis-naphthalimide anti-tumor agents. A representative compound in this series, XB596, exhibits potent in vitro growth inhibitory activity against several human and murine leukemic and solid tumor lines in culture, with IC50 values ranging from 7.2 to 147.5 nM. XB596 was almost as equally growth inhibitory against three doxorubicin-resistant cell lines compared with their parental lines. Using a human tumor colony-forming assay, XB596 demonstrated cytocidal activity against fresh human tumors taken directly from patients, with 23 of 25 evaluable tumors responding to a continuous exposure of 1 microgram/ml of XB596. When L1210 cells were incubated with XB596 for 1 h, the incorporation of uridine and thymidine into RNA and DNA, respectively, was inhibited with IC50 values of 0.14 microM. DNA single-strand breaks, but not double-strand breaks, were detected in XB596-treated L1210 cells. XB596 bound to DNA with guanine-cytosine sequence selectivity as shown by an indirect ethidium bromide displacement assay. XB596 was shown to interact with DNA by a spectrophotometric titration assay, with an estimated binding constant of 4.7 +/- 2.2 +/- 10(6) M-1. XB596 unwound supercoiled DNA as measured by agarose gel electrophoresis. These data are consistent with XB596 being a DNA intercalator. In vivo, XB596 demonstrated good anti-tumor activity against two human solid tumors (DLD-2 colon adenocarcinoma and MX-1 mammary carcinoma) xenografted in nude mice, but has not demonstrated anti-leukemic activity. In summary, XB596 is a pre-clinical anti-cancer agent which interacts with DNA and demonstrates good in vivo anti-tumor activity against human solid tumor xenografts.

A novel series of diaminoanthraquinones was discovered initially as protein kinase C inhibitors with IC50s in the 50-100 microM range. They exhibited potent tumor cell growth inhibitory activity in vitro without cross resistance to adriamycin. Further evaluation of two of the most active compounds NSC 639365 (3) and NSC 639366 (4) in human tumor cloning assay showed potent cytocidal activity. The results suggest therapeutical potentials against human tumors.

Shiraiachrome-A and -B have been isolated from the mycelium of the Chinese bamboo fungus Shiraia bambusicola as the cytotoxic principles. A series of new perylene derivatives (7-27) related to Shiraiachrome-A and -B as well as Calphostin-C have been synthesized and evaluated for their cytotoxicity, antiviral activity, and inhibitory activity against protein kinase C. The results indicated that 11 and 12 are potent cytotoxic agents against HCT-8, RPMI-7951, and TE-671 solid tumor cells, whereas 24 and 26 demonstrated strong antiviral activity against HSV-1 and HSV-2. Compound 10 is an inhibitor of protein kinase C.

A new class of antimitotic agents, derivatives of 2-styrylquinazolin-4(3H)-one (SQZ), was recently described [J. Med. Chem. 33:1721-1728 (1990)]. Because they appeared to interact at a new ligand binding site on tubulin, we attempted to determine their mechanism of action as inhibitors of tubulin polymerization. Although in initial studies inhibition of colchicine binding was negligible, substantial and competitive inhibition of this reaction could be demonstrated with very short incubation times (less than 5 min), provided that a relatively low colchicine to tubulin ratio was used. The initial apparent failure to inhibit colchicine binding resulted from extremely rapid binding to tubulin and dissociation from tubulin by the SQZ derivatives, in comparison with the slow, temperature-dependent, poorly reversible binding of colchicine. The most inhibitory of the SQZ derivatives in the colchicine binding assay was 6-methyl-2-styrylquinazolin-4(3H)-one (NSC 379310), and its interaction with tubulin, particularly as an inhibitor of colchicine binding, was compared with that of 2-methoxy-5-(2',3',4'-trimethoxyphenyl)tropone (MTPT), because the binding parameters of MTPT with tubulin have been well described. The data indicate that NSC 379310 binds to tubulin and dissociates from the protein about 3 times as rapidly as MTPT. The other SQZ derivatives with equal or greater potency as inhibitors of tubulin polymerization but apparently less potency as inhibitors of colchicine binding presumably bind to and/or dissociate from tubulin even more rapidly than does NSC 379310.

A novel series of 2-styrylquinazolin-4(3H-ones which inhibited tubulin polymerization and the growth of L1210 murine leukemia cells was discovered. Extensive structure-activity relationship studies suggest that the entire quinazolinone structure was required, but activity was further enhanced by halide or small hydrophobic substituents at position 6. These analogues did not substantially interfere with the binding of radiolabeled colchicine, vinblastine, or GTP to tubulin and weakly stimulated GTP hydrolysis uncoupled from polymerization. Several analogues have shown in vivo tumor growth inhibitory activity in the L1210 leukemia model, with the lead compound 5o exhibiting good antitumor activity against murine solid tumors as well as human tumor xenografts.

Exoerythrocytic schizonts of Plasmodium cynomolgi and P. knowlesi were examined by electron microscopy in biopsy samples of primate livers. With maturity the parasitophorous vacuole membrane becomes highly sculptured by the addition of a discontinuous dense thickening, the distribution of which can be a distinguishing character between these two species. The parasitophorous vacuole membrane follows the contours of the parasite faithfully with a minimal surrounding vacuole. The marked destruction of the cytoplasm of the host hepatocyte by most of the parasites studied however gave the distinct, but erroneous, appearance of a large parasitophorous vacuole at the light microscope level. The mature parasite often exhibited a highly invaginated surface contour with the result that the cytoplasm of the host cell and parasite became intimately interdigitated, this interweaving is unlikely to be recognized in light microscopic studies.

A new technique of transduodenal choledochoduodenostomy is proposed. It is easy to perform and leaves no blind tube below the stoma and biliary pancreatic leakage is eliminated.

Two rhesus monkeys were each infected with 2.1 x 10(6) sporozoites of Plasmodium cynomolgi bastianellii; one was treated with 1.0 mg of pyrimethamine base per kg body weight for 5 d after sporozoite inoculation. A further 2 monkeys were each infected with 9.75 x 10(6) sporozoites of the same parasite; one was treated with 10 mg of proguanil per kg body weight for 4 out of 5 d after inoculation. The treated monkeys showed a delayed primary parasitaemia and relapses. In sections of liver biopsies taken 7.5 d after sporozoite inoculation, all monkeys showed numerous hypnozoites. However, there were no full grown schizonts and only rare retarded schizonts in the treated monkeys, in contrast to the untreated monkeys which had many mature or nearly mature schizonts. Later biopsies confirmed the continued presence of hypnozoites in all monkeys.

Epimeric 6-amino derivatives of naloxone and naltrexone have been synthesized and the configuration at the C-6 chiral center was determined from NMR studies. All of the derivatives possess narcotic antagonist activity in mice, with each of the 6beta epimers having greater potency than the corresponding 6alpha epimers. In vitro binding experiments indicate that the affinities of these epimers parallel thier in vivo potencies. Slight antinociceptic properties were observed with three of the four compounds. The naloxone derivatives 3a and 3b appear to be attractive candidates for investigation as long-acting narcotic antagonists in view of their fourfold greater duration of action relative to the other antagonists (1, 2, 4a, and 4b).

Chlornaltrexamine (CNA) produces ultralong-lasting (3--6 days) narcotic antagonism in mice and persistent stereospecific binding to rat-brain homogenate. Protection studies in mice suggest that CNA mediates its narcotic antagonist effects by interacting with the same receptors that are occupied by naloxone. A single icv dose of CNA also has been found to inhibit the development of physical dependence in mice for at least 3 days. These studies suggest that CNA exerts its sustained effects by selective covalent association with opioid receptors.

Treatment of SV40-infected monkey cells with amonafide (benzisoquinolinedione), an intercalative antitumor drug, resulted in rapid accumulation of linearized intracellular SV40 DNA molecules that were protein linked. Studies using purified mammalian DNA topoisomerase II have shown that amonafide and its structural analogs interfere with the breakage-rejoining reaction of the enzyme by stabilizing a reversible enzyme-DNA "cleavable complex." Denaturation of the cleavable complex with sodium dodecyl sulfate resulted in DNA cleavage and the covalent association of topoisomerase II polypeptides with the cleaved DNA. Unwinding measurements indicate that amonafide is a DNA intercalator. These results suggest that amonafide and its structural analogs (e.g., mitonafide) represent a new class of intercalative topoisomerase II-active antitumor drugs. Different from other topoisomerase II-active antitumor drugs, amonafide and mitonafide induce specific DNA cleavage at a single major site on pBR322 DNA. The strong site specificity of amonafide may allow detailed characterization of the intercalator-stabilized, topoisomerase II-DNA cleavable complex.

The ultrastructural changes induced by the administration of the antimalarial drug, qinghaosu, were studied in monkeys (Macaca assamensis) infected with Plasmodium inui. Significant changes, notably mitochondrial swelling within the parasites but not within host cells, were first observed 2.5 hr after exposure to qinghaosu. This suggests that the target of qinghaosu may be the parasite's mitochondria, as occurs with primaquine. This is in contrast to the most widely used antimalarial drug, chloroquine.