Algebraic connectivity of layered path graphs under node deletion

This paper studies the relation between node deletion and the algebraic connectivity for a graph with a hierarchical structure represented by layers. The problem is motivated by a mobile robot formation control guided by a leader. In particular, we consider a scenario in which robots may leave the network resulting in the removal of the nodes and the associated edges. We show that the existence of at least one neighbor in the upper layer is crucial for the algebraic connectivity not to deteriorate by node deletion

Position-controlled trapping of nanoparticles and quantum dots on a fiber taper

We investigate numerically and experimentally the properties of a two color optical fiber taper trap, for which the evanescent field of the modes in the fiber taper give rise to a three-dimensional trapping potential. Experimentally, we use the technique to confine colloidal nanoparticles near the surface of an optical fiber taper, and show that the trapping position of the particles is adjustable by controlling the relative power of two modes in the fiber. We also demonstrate a proof of principle application by trapping quantum dots together with gold nanoparticles in a configuration where the trapping fields double as the excitation field for the quantum dots. This scheme will allow the positioning of quantum emitters in order to adjust coupling to resonators combined with the fiber taper.Comment: 13 pages, 9 figures. Comments welcom

Efficacy of tumor-targeting Salmonella typhimurium A1-R in combination with anti-angiogenesis therapy on a pancreatic cancer patient-derived orthotopic xenograft (PDOX) and cell line mouse models.

The aim of the present study was to examine the efficacy of tumor-targeting Salmonella typhimurium A1-R treatment following anti-vascular endothelial growth factor (VEGF) therapy on VEGF-positive human pancreatic cancer. A pancreatic cancer patient-derived orthotopic xenograft (PDOX) that was VEGF-positive and an orthotopic VEGF-positive human pancreatic cancer cell line (MiaPaCa-2-GFP) as well as a VEGF-negative cell line (Panc-1) were tested. Nude mice with these tumors were treated with gemcitabine (GEM), bevacizumab (BEV), and S. typhimurium A1-R. BEV/GEM followed by S. typhimurium A1-R significantly reduced tumor weight compared to BEV/GEM treatment alone in the PDOX and MiaPaCa-2 models. Neither treatment was as effective in the VEGF-negative model as in the VEGF-positive models. These results demonstrate that S. typhimurium A1-R following anti-angiogenic therapy is effective on pancreatic cancer including the PDOX model, suggesting its clinical potential

The tumor-educated-macrophage increase of malignancy of human pancreatic cancer is prevented by zoledronic acid.

We previously defined macrophages harvested from the peritoneal cavity of nude mice with subcutaneous human pancreatic tumors as "tumor-educated-macrophages" (Edu) and macrophages harvested from mice without tumors as "naïve-macrophages" (Naïve), and demonstrated that Edu-macrophages promoted tumor growth and metastasis. In this study, Edu- and Naïve-macrophages were compared for their ability to enhance pancreatic cancer malignancy at the cellular level in vitro and in vivo. The inhibitory efficacy of Zoledronic acid (ZA) on Edu-macrophage-enhanced metastasis was also determined. XPA1 human pancreatic cancer cells in Gelfoam co-cultured with Edu-macrophages proliferated to a greater extent compared to XPA1 cells cultured with Naïve-macrophages (P = 0.014). XPA1 cells exposed to conditioned medium harvested from Edu culture significantly increased proliferation (P = 0.016) and had more migration stimulation capability (P<0.001) compared to cultured cancer cells treated with the conditioned medium from Naïve. The mitotic index of the XPA1 cells, expressing GFP in the nucleus and RFP in the cytoplasm, significantly increased in vivo in the presence of Edu- compared to Naïve-macrophages (P = 0.001). Zoledronic acid (ZA) killed both Edu and Naïve in vitro. Edu promoted tumor growth and metastasis in an orthotopic mouse model of the XPA1 human pancreatic cancer cell line. ZA reduced primary tumor growth (P = 0.006) and prevented metastasis (P = 0.025) promoted by Edu-macrophages. These results indicate that ZA inhibits enhanced primary tumor growth and metastasis of human pancreatic cancer induced by Edu-macrophages

Tumor-Targeting Salmonella typhimurium A1-R in Combination with Trastuzumab Eradicates HER-2-Positive Cervical Cancer Cells in Patient-Derived Mouse Models.

We have previously developed mouse models of HER-2-positive cervical cancer. Tumors in nude mice had histological structures similar to the original tumor and were stained by anti-HER-2 antibody in the same pattern as the patient's cancer. We have also previously developed tumor-targeting Salmonella typhimurium A1-R and have demonstrated its efficacy against patient-derived tumor mouse models, both alone and in combination. In the current study, we determined the efficacy of S. typhimurium A1-R in combination with trastuzumab on a patient-cancer nude-mouse model of HER-2 positive cervical cancer. Mice were randomized to 5 groups and treated as follows: (1) no treatment; (2) carboplatinum (30 mg/kg, ip, weekly, 5 weeks); (3) trastuzumab (20 mg/kg, ip, weekly, 5 weeks); (4) S. typhimurium A1-R (5 × 107 CFU/body, ip, weekly, 5 weeks); (5) S. typhimurium A1-R (5 × 107 CFU/body, ip, weekly, 5 weeks) + trastuzumab (20 mg/kg, ip, weekly, 5 weeks). All regimens had significant efficacy compared to the untreated mice. The relative tumor volume of S. typhimurium A1-R + trastuzumab-treated mice was smaller compared to trastuzumab alone (p = 0.007) and S. typhimurium A1-R alone (p = 0.039). No significant body weight loss was found compared to the no treatment group except for carboplatinum-treated mice (p = 0.021). Upon histological examination, viable tumor cells were not detected, and replaced by stromal cells in the tumors treated with S. typhimurium A1-R + trastuzumab. The results of the present study suggest that S. typhimurium A1-R and trastuzumab in combination are highly effective against HER-2-expressing cervical cancer

Decadal–centennial-scale solar-linked climate variations and millennial-scale internal oscillations during the Early Cretaceous

Understanding climate variability and stability under extremely warm ‘greenhouse’ conditions in the past is essential for future climate predictions. However, information on millennial-scale (and shorter) climate variability during such periods is scarce, owing to a lack of suitable high-resolution, deep-time archives. Here we present a continuous record of decadal- to orbital-scale continental climate variability from annually laminated lacustrine deposits formed during the late Early Cretaceous (123–120 Ma: late Barremian–early Aptian) in southeastern Mongolia. Inter-annual changes in lake algal productivity for a 1091-year interval reveal a pronounced solar influence on decadal- to centennial-scale climatic variations (including the ~ 11-year Schwabe cycle). Decadally-resolved Ca/Ti ratios (proxy for evaporation/precipitation changes) for a ~ 355-kyr long interval further indicate millennial-scale (~ 1000–2000-yr) extreme drought events in inner-continental areas of mid-latitude palaeo-Asia during the Cretaceous. Millennial-scale oscillations in Ca/Ti ratio show distinct amplitude modulation (AM) induced by the precession, obliquity and short eccentricity cycles. Similar millennial-scale AM by Milankovitch cycle band was also previously observed in the abrupt climatic oscillations (known as Dansgaard–Oeschger events) in the ‘intermediate glacial’ state of the late Pleistocene, and in their potential analogues in the Jurassic ‘greenhouse’. Our findings indicate that external solar activity forcing was effective on decadal–centennial timescales, whilst the millennial-scale variations were likely amplified by internal process such as changes in deep-water formation strength, even during the Cretaceous ‘greenhouse’ period

Crystal Structures and Magnetic Properties of Diaquatetrapyridinenickel(II) and Diaquatetrapyridinecobalt(II) Complexes

Metal complexes with pyridine ligands (py) have not been crystallographically characterized in large numbers, while a large number of 2,2′-bipyridine (bpy) complexes have been structurally characterized. Against this background of scarcity of py complexes, the aim of this study was to characterize the structures and magnetic properties of complexes with pyridine ligands. In this study, new py complexes, trans-[Ni(H2O)2(py)4][BPh4]2·4py (1) and trans-[Co(H2O)2(py)4][BPh4]2·4py (2), were prepared and characterized by the single-crystal X-ray diffraction method and magnetic measurements. In the crystal structure analysis, both complexes were found to have octahedral trans-N2O4 coordination geometry, and the coordination of the trans-aqua ligands was found to be enhanced by the hydrogen-bonded pyridine molecules as a base. In the simultaneous analysis of magnetic susceptibility and magnetization, both complexes were found to show strong magnetism in one direction (χz > χx, χy; Mz > Mx, My), and this was explained by the enhancement of the axial aqua ligands. In the nickel(II) complex, the strong axial ligand field was found to cause negative zero-field splitting (D 4T1 ground state to show the magnetic behavior

Laparoscopic low anterior resection for rectal cancer with rectal prolapse: a case report

Abstract Background Rectal cancer with rectal prolapse is rare, described by only a few case reports. Recently, laparoscopic surgery has become standard procedure for either rectal cancer or rectal prolapse. However, the use of laparoscopic low anterior resection for rectal cancer with rectal prolapse has not been reported. Case presentation A 63-year-old Japanese woman suffered from rectal prolapse, with a mass and rectal bleeding for 2 years. An examination revealed complete rectal prolapse and the presence of a soft tumor, 7 cm in diameter; the distance from the anal verge to the tumor was 5 cm. Colonoscopy demonstrated a large villous tumor in the lower rectum, which was diagnosed as adenocarcinoma on biopsy. We performed laparoscopic low anterior resection using the prolapsing technique without rectopexy. The distal surgical margin was more than 1.5 cm from the tumor. There were no major perioperative complications. Twelve months after surgery, our patient is doing well with no evidence of recurrence of either the rectal prolapse or the cancer, and she has not suffered from either fecal incontinence or constipation. Conclusions Laparoscopic low anterior resection without rectopexy can be an appropriate surgical procedure for rectal cancer with rectal prolapse. The prolapsing technique is useful in selected patients