Acoustic phonon excitation in gold probed by time-resolved photoemission electron microscopy.

Electron-phonon coupling is an important energy transfer mechanism in solids after ultrafast laser excitation. In this study, we present an extreme ultraviolet (EUV) and infrared (IR) pump-probe photoemission experiment to investigate the electron-phonon coupling in nonequilibrium gold. The energy of IR-laser-emitted photoelectrons is shifted due to the EUV photoemission and oscillates with a ∼4THz frequency. Such oscillation is considered as the effective excitation of the longitudinal acoustic phonon mode in gold through the spectral-dependent electron-phonon coupling. Our study showcases the capability of time-resolved photoemission electron microscopy to monitor the non-equilibrium lattice vibrations with ultrahigh spatial and temporal resolution.

The significance of preoperative serum carcinoembryonic antigen levels in the prediction of lymph node metastasis and prognosis in locally advanced gastric cancer: a retrospective analysis.

BACKGROUND: In this study, we aimed to investigate the preoperative serum carcinoembryonic antigen (CEA) in the diagnosis of positive lymph node metastasis (LNM), and to evaluated the relationship between CEA and survival in patients with locally advanced gastric cancer (LAGC). METHODS: The significance of the preoperative serum CEA level for the diagnose of LAGC and prediction of LNM was determined using the receiver operating characteristic (ROC) curve. The areas under the ROC of CEA were compared with those of other tumor markers or imaging examination including CT and MRI. Logistic regression was utilized to identify the risk factors predicting positive LNM. Independent prognosis factors were evaluated using univariate and multivariate COX regression analyses. RESULTS: The ROC curves showed that the AUCs of CEA, CA199, and CA125 for diagnosing LAGC were 0.727, 0.594, and 0.566. When used to predict LNM, the AUC of CEA, CA199 and CA125 were 0.696, 0.531, and 0.588. Logistic regression analysis demonstrated that preoperative serum CEA were significantly associated with positive LNM. On combining imaging examination with CEA, the sensitivity and specificity were 85.3 and 79.4%, respectively, with the AUC equal to 0.853. The combination of CEA and imaging examination preformed the highest levels of AUC and sensitivity for diagnosing LNM, which is significantly higher than using either of them alone. Although patients with abnormal CEA have a poor prognosis, two models of multivariate analysis showed that CEA was not the independent prognosis factor for survival. CONCLUSIONS: CEA can be used to diagnose gastric cancer and determine whether it has LNM. Moreover, combined with CEA could improve the diagnostic sensitivity of imaging examination for lymph node involvement.

High-Order Harmonic Generation in Photoexcited Three-Dimensional Dirac Semimetals.

High-order harmonic generation (HHG) in condensed matter is highly important for potential applications in various fields, such as materials characterization, all-optical switches, and coherent light source generation. Linking HHG to the properties or dynamic processes of materials is essential for realizing these applications. Here, a bridge has been built between HHG and the transient properties of materials through the engineering of interband polarization in a photoexcited three-dimensional Dirac semimetal (3D-DSM). It has been found that HHG can be efficiently manipulated by the electronic relaxation dynamics of 3D-DSM on an ultrafast time scale of several hundred femtoseconds. Furthermore, time-resolved HHG (tr-HHG) has been demonstrated to be a powerful spectroscopy method for tracking electron relaxation dynamics, enabling the identification of electron thermalization and electron-phonon coupling processes and the quantitative extraction of electron-phonon coupling strength. This demonstration provides insights into the active control of HHG and measurements of the electron dynamics.

Layer-dependent ultrafast carrier dynamics of PdSe2 investigated by photoemission electron microscopy.

For atomically thin two-dimensional materials, variations in layer thickness can result in significant changes in the electronic energy band structure and physicochemical properties, thereby influencing the carrier dynamics and device performance. In this work, we employ time- and energy-resolved photoemission electron microscopy to reveal the ultrafast carrier dynamics of PdSe2 with different layer thicknesses. We find that for few-layer PdSe2 with a semiconductor phase, an ultrafast hot carrier cooling on a timescale of approximately 0.3 ps and an ultrafast defect trapping on a timescale of approximately 1.3 ps are unveiled, followed by a slower decay of approximately tens of picoseconds. However, for bulk PdSe2 with a semimetal phase, only an ultrafast hot carrier cooling and a slower decay of approximately tens of picoseconds are observed, while the contribution of defect trapping is suppressed with the increase of layer number. Theoretical calculations of the electronic energy band structure further confirm the transition from a semiconductor to a semimetal. Our work demonstrates that TR- and ER-PEEM with ultrahigh spatiotemporal resolution and wide-field imaging capability has great advantages in revealing the intricate details of ultrafast carrier dynamics of nanomaterials.

[Study on molecular phylogeny of Schistosoma bovis based on mitochondrial DNA sequence and gene order].

OBJECTIVE: To determine the nucleotide sequence of the partial mitochondrial (mt) genome and the order of the mitochondrial protein-coding genes for Schistosoma bovis for analysis of possible phylogenetic position of this species in the genus Schistosoma. METHODS: The genomic DNA of adult worms were extracted by the GNT-K method. The target regions were amplified by PCR using a degenerated primer and specific primer. The PCR products were purified before ligating into the pGEM1 T-vector system. Recombinant plasmids were amplified in Escherichia coli, extracted and purified using routine methods. The nucleotide sequences were determined with an ABI PRISM 3100-Avant DNA sequencer using a BigDye Terminators v3.1 Cycle Sequencing Kit (Applied Bio-systems, CA, U.S.A.) with two T-vector specific primers (T7 and SP6). Positive colonies were sequenced with two internal specific primers to obtain the full sequence of each fragment on both strands by means of primer walking. Sequences of related schistosomes were retrieved from GenBank and aligned with our data. Gene trees were constructed using neighbor joining methods. RESULTS: The nucleotide sequence was determined and the gene order of this region in S. bovis was found as follows: NADHdehydrogenase4 (nad4)-trnQ (Gln)-trnK(Lys)-NADH dehydrogenase 3(nad3)-trnD (Asp)-NADH dehydrogenase 1(nad1). The gene order covering such region of S. bovis was similar to that of the African Schistosoma species, but strikingly different from the Asian species. Phylogenetic trees inferred from the alignment including partial nad4, nad3, partial nad1 and partial nad4+nad3+nad1 sequence for other 8 Schistosoma spp., respectively, revealed that S. bovis is placed proximally to S. haematobium in the African sub-group, which is identical with those placed by gene order in the African clade. CONCLUSION: The mtDNA analysis based on mitochondrial DNA sequence and the gene order strongly support the hypothesis that S. bovis belongs to the African schistosome clade rather than the Asian Schistosoma species.

Primary synovial sarcoma of the duodenal bulb: a case report and review of the literature.

Primary synovial sarcoma of the duodenal bulb is a rare mesenchymal tumor with special morphological features. It usually originates from the major joints or tendon sheaths of the extremities and mostly seen in young population, but rarely found in gastrointestinal tract. In this manuscript, we reported the first case of synovial sarcoma arising between the intestinal wall of the duodenal bulb with a concomitant SYT/SSX type of the t(X;18) translocation. A 49-year-old male presented to our hospital with a 2-month history of upper abdominal pain along with a 4-day amply jaundice. Tumor marker testing showed only a slight increase of carbohydrate antigen 19-9 (CA19-9). A computed tomography scan of his abdomen showed that indeterminate tissue occupied the duodenal bulb wall, compressed the surrounding tissues, and measured roughly 5.0 cm × 7.7 cm × 8.7 cm. Since the sarcoma grows between the intestinal wall, which cannot be detected by endoscopy, an initial diagnosis of duodenal wall stromal tumor was made at that time. Postoperative Immunohistochemistry results showed that the tumor was positive for the expression of transducin-like enhancer of split 1, B-cell lymphoma 2, and Vimentin. These pathological findings were indicative of the diagnosis of synovial sarcoma, but still did not provide sufficient diagnostic evidence. Finally we confirmed the diagnosis by using fluorescence in situ hybridization (FISH) with detection of the t(X;18) (SYT-SSX) translocation. No such lesions were found on preoperative examination, so a diagnosis of primary duodenal synovial sarcoma was made. After literature review, we found four reports of duodenal synovial sarcomas, all of which could be detected endoscopically, but there were no results of long-term follow-up. This case is the first reported case of synovial sarcoma arising between the intestinal walls of the duodenal bulb treated twice with ifosfamide and followed up for 13 months without recurrence.

Docetaxel, oxaliplatin, leucovorin, and 5-fluorouracil (FLOT) as preoperative and postoperative chemotherapy compared with surgery followed by chemotherapy for patients with locally advanced gastric cancer: a propensity score-based analysis.

Introduction: Docetaxel, oxaliplatin, leucovorin, and 5-fluorouracil (FLOT) may improve overall survival (OS) in patients with locally advanced gastric cancer (LAGC); however, evidence for its use as a standard treatment has not been established in China. The aim of this study was to investigate the effectiveness, safety, and feasibility of the FLOT regimen as neoadjuvant chemotherapy in Chinese patients with resectable LAGC. Methods: We conducted an observational study to compare the effectiveness of FLOT regimen consisting of docetaxel (60 mg/m2), oxaliplatin (85 mg/m2), leucovorin (200 mg/m2), and 5-fluorouracil (2,600 mg/m2 as a 24 hr infusion), all given on day 1 and administered every 2 weeks versus initial surgery followed by chemotherapy in patients with clinical T3-4 LAGC. OS was compared by using the Cox proportional hazards regression model and the Kaplan-Meier curve adjusted by inverse probability of treatment weighting (IPTW) and propensity score-matched (PSM) analysis. In addition, we performed subgroup analyses to determine the effectiveness of the FLOT regimen in clinically relevant patient subsets. Results: Overall, 47 patients who received initial FLOT chemotherapy and 269 patients who received initial surgery were enrolled in this study. In the PSM analysis, the FLOT-first group showed favorable OS compared with the surgery-first group (41 vs 41 [HR, 0.416; 95% CI, 0.218-0.794; P=0.008]), and 3-year survival rates were 58.7% and 30.9% in the FLOT-first group and surgery-first group, respectively. IPTW analysis showed similar results. However, the effect of FLOT was low (HR, 0.868; 95 CI%, 0.215-3.504) in patients without lymph node metastasis. Conclusion: Our study suggests that preoperative FLOT chemotherapy is safe and feasible. In terms of OS, FLOT may be superior to initial surgery followed by chemotherapy in reducing morbidity with resectable LAGC.

[Evaluation of immunogenicity and protection efficacy of the recombinant hypoxanthine-guanine-xanthine of plasmodium falciparum in mice].

OBJECTIVE: To investigate immunogenicity and protection efficacy of the recombinant hypoxanthine-guanine-xanthine (HGXPRT) of Plasmodium falciparum expressed in Pichia pastoris. METHODS: 35 BALB/c mice were divided randomly into five groups: HGXPRT+ISA720 experiment group, HGXPRT+Freund experiment group, ISA720 adjuvant control group, Freund adjuvant control group, and blank control group. BALB/c mice were subcutaneously immunized three times with the HGXPRT protein formulated by either Freund or ISA720 adjuvants at a three weeks interval. Mice were bled via tail vein at 2 weeks after each immunization. Specific antibodies were detected by ELISA as well as IFAT using cultured parasites. The immunized mice were challenged with 10(5) P. yoelii 10 days after the third immunization and parasitemia was monitored daily by examining Giemsa-stained thin film. RESULTS: Strong immune response was induced by the HGXPRT antigen formulated with the adjuvant. Antibody titers of more than 1:10(5) were detected after the third immunization while no specific antibody was detected in the mice immunized with adjuvants only. The antibodies against HGXPRT recognized the cultured parasite by IFAT. Four days after mice were challenged with P. yoelii, high parasitemia appeared in the two control groups, which were 24 h earlier than experiment groups. The mean parasitemia of HGXPRT+ISA720 experiment group (29.3%) was significantly lower than that of control groups (70.0%) (P<0.05). The mean parasitemia of HGXPRT+Freund experiment group (51.0%) was significantly lower than that of adjuvant control (60.7%) and blank control(70.0%) (P<0.05). CONCLUSION: HGXPRT of P. falciparum expressed in Pichia pastoris was highly immunogenic in mice. Antibody against the recombinant protein recognizes the cultured parasites, and immunization of mice with the recombinant protein provides partial protection against the challenge of P. yoelii.

Sequence variability in four mitochondrial genes among pinworm Aspicularis tetraptera isolates from laboratory mice in four provinces, China.

This research aimed at exploring sequence variability in four mitochondrial (mt) genes, namely, cytochrome c oxidase subunit 1 (cox1), cytochrome b (cytb) and NADH dehydrogenase subunits 1 and 5 (nad1 and nad5), among pinworm Aspicularis tetraptera isolates from laboratory mice in four different provinces, China. A part of the cox1 (pcox1), cytb (pcytb), nad1 and nad5 genes (pnad1 and pnad5) were amplified separately from individual pinworms by polymerase chain reaction (PCR) and sequenced to determine sequence variations and examine their phylogenetic relationships. Herein, the intra-specific sequence variations within A. tetraptera were 0-0.5% for pcox1, 0-1.4% for pcytb, 0-1.8% for pnad1 and 0-1.7% for pnad5, respectively. In contrast, the inter-specific sequence differences among members of the Oxyuridae were significantly higher, being 13.7-17.0% for pcox1, 24.5-34.7% for pcytb, 26.6-29.6% for pnad1 and 24.4-25.5% for pnad5, respectively. Three methods, namely, Bayesian inference (BI), maximum likelihood (ML) and maximum parsimony (MP), were used for phylogenetic analyses based on the combined sequences of the four mt gene sequences, and the results indicated that all A. tetraptera samples form monophyletic groups, but samples from the same geographical origin did not always cluster together. This study demonstrated the existence of low-level intra-specific variation in four mtDNA sequences among A. tetraptera isolates from laboratory mice in different geographic regions in China, indicating no obvious geographical distinction among A. tetraptera isolates in China. These findings have important implications for studying systematics, molecular epidemiology and population genetics of A. tetraptera.

[Studies on the relationship between the level of cytokine and liver function in patients with clonorchiasis sinensis].

OBJECTIVE: To explore the relationship between cytokine level and liver function among patients infected with Clonorchis sinensis. METHODS: 47 patients were divided into three groups according to the degree of Child-Pugh liver function grade: 20 in group A (3-4 scores), 15 in group B (5-6 scores) and 12 in group C (7-9 scores). Interleukin 2 (IL-2), soluble IL-2 receptor (sIL-2R), interleukin 8 (IL-8) and tumor necrosis factor (TNF-alpha) were examined by radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA). Automatic biochemical analyzer was employed for the determination of serum level of total bilirubin (TBL), albumin (ALB) and alanine aminotransferase (ALT). Data were analyzed with SAS statistic software. RESULTS: Serum levels of sIL-2R, IL-8 and TNF-alpha from patients were significantly higher than those obtained from healthy people (P<0.05, P<0.05, P<0.01), whereas the IL-2 level was significantly lower than the former (P<0.01). With the affected degree of the liver, serum levels of sIL-2R, IL-8 and TNF-alpha increased, in contrast to the decrease of IL-2 level. The differences were significant between groups A and C (P<0.05). The level of sIL-2R and TNF-alpha directly correlated with that of TBL (r=0.331 P<0.05, r=0.518 P<0.01) and ALT (r=0.475 P<0.01, r=0.285 P<0.05) respectively, but inversely correlated with the level of ALB (r=-0.319 P<0.05, r=-0.665 P<0.01). CONCLUSION: The infection of Clonorchis sinensis results in the reduction of cellular immune function of the patients. Certain relationship exists between serum cytokine level and liver function. Two cytokines, sIL-2R and TNF-alpha, are involved in the process of pathology.

Genetic variation among Clonorchis sinensis isolates from different hosts and geographical locations revealed by sequence analysis of mitochondrial and ribosomal DNA regions.

The present study examined genetic variability among Clonorchis sinensis isolates from four different geographical localities (Guangzhou, Nanning, Jiamusi and Daqing) and host species (cats, dogs, human and rabbits) in Mainland China by sequence analyses of two mitochondrial DNA (mtDNA) genes, namely NADH dehydrogenase subunits 2, 5 (nad2 and nad5) and ribosomal internal transcribed spacer 1 (ITS1). A portion of the ITS1, nad2 (pnad2) and nad5 (pnad5) was amplified by polymerase chain reaction separately from adult C. sinensis individuals and the amplicons were subjected to sequencing from both directions. The length of the sequences of ITS1, pnad2 and pnad5 was 643, 666 and 771 bp, respectively. The intraspecific sequence variations within C. sinensis were 0-1.7% for ITS1, 0-1.4% for pnad2 and 0-0.9% for pnad5. The interspecific sequence variations within other zoonotic trematodes, which were published previously, were 4.5-84.9% for ITS1, 21.9-43.6% for pnad2 and 19.2-48.9% for pnad5. The A+T contents of the sequences were 45.26-45.88% (ITS1), 62.91-63.51% (pnad2) and 58.24-58.63% (pnad5). Phylogenetic analyses using ribosomal and mitochondrial sequence data set, with three different computational algorithms (Bayesian inference, maximum parsimony and maximum likelihood), all revealed distinct groups with high statistical support. These findings demonstrated the existence of low-level intraspecific variations in ribosomal DNA (rDNA) and mtDNA sequences among C. sinensis isolates from four different regions and hosts in China and elucidated that mtDNA sequences and rDNA sequences provided reliable genetic markers for phylogenetic studies of zoonotic trematodes.

Molecular cloning and characterization of taurocyamine kinase from Clonorchis sinensis: a candidate chemotherapeutic target.

BACKGROUND: Adult Clonorchis sinensis lives in the bile duct and causes endemic clonorchiasis in East Asian countries. Phosphagen kinases (PK) constitute a highly conserved family of enzymes, which play a role in ATP buffering in cells, and are potential targets for chemotherapeutic agents, since variants of PK are found only in invertebrate animals, including helminthic parasites. This work is conducted to characterize a PK from C. sinensis and to address further investigation for future drug development. METHODOLOGY/PRINCIPAL FINDINGS: [corrected] A cDNA clone encoding a putative polypeptide of 717 amino acids was retrieved from a C. sinensis transcriptome. This polypeptide was homologous to taurocyamine kinase (TK) of the invertebrate animals and consisted of two contiguous domains. C. sinensis TK (CsTK) gene was reported and found consist of 13 exons intercalated with 12 introns. This suggested an evolutionary pathway originating from an arginine kinase gene group, and distinguished annelid TK from the general CK phylogenetic group. CsTK was found not to have a homologous counterpart in sequences analysis of its mammalian hosts from public databases. Individual domains of CsTK, as well as the whole two-domain enzyme, showed enzymatic activity and specificity toward taurocyamine substrate. Of the CsTK residues, R58, I60 and Y84 of domain 1, and H60, I63 and Y87 of domain 2 were found to participate in binding taurocyamine. CsTK expression was distributed in locomotive and reproductive organs of adult C. sinensis. Developmentally, CsTK was stably expressed in both the adult and metacercariae stages. Recombinant CsTK protein was found to have low sensitivity and specificity toward C. sinensis and platyhelminth-infected human sera on ELISA. CONCLUSION: CsTK is a promising anti-C. sinensis drug target since the enzyme is found only in the C. sinensis and has a substrate specificity for taurocyamine, which is different from its mammalian counterpart, creatine.

miR-761 regulates the mitochondrial network by targeting mitochondrial fission factor.

Mitochondria are dynamic organelles that constantly undergo fission and fusion. The balance between fission and fusion determines the fate of the cell. In this study, we show that mitochondrial fission factor (MFF) is upregulated upon hydrogen peroxide treatment or ischemia/reperfusion (I/R) injury. Knockdown of MFF attenuated hydrogen peroxide- and I/R injury-induced cardiomyocyte apoptosis and myocardial infarction. We found that MFF is a direct target of miR-761, and miR-761 inhibits mitochondrial fission and cardiomyocyte apoptosis by repressing MFF. This study reveals a novel model of mitochondrial fission regulation, which is composed of miR-761 and MFF. Modulation of their levels may provide a new approach for tackling apoptosis and myocardial infarction.