A randomized trial of Bacteroides fragilis 839 on preventing chemotherapy-induced myelosuppression and gastrointestinal adverse effects in breast cancer patients.

BACKGROUND AND OBJECTIVES: To evaluate the potential benefits of Bacteroides fragilis 839 (BF839), a next-generation probiotics, in reducing myelosuppression and gastrointestinal toxicity associated with chemotherapy in breast cancer patient. METHODS AND STUDY DESIGN: 40 women with early breast cancer were randomly assigned to the BF839 (n=20) or placebo (n=20) during the administration of adjuvant chemotherapy (4 cycles of epirubicin 100mg/m2 and cyclophosphamide 600mg/m2). Myelosuppression and gastrointestinal adverse effects were monitored in both groups. RESULTS: Throughout the four treatment cycles, the percentage of patients experiencing myelosuppression was 42.5% in the BF839 group, significantly lower than the 66.3% observed in the control group (p=0.003). Two patients in the BF839 group and three patients in the placebo group received recombinant human granulocyte colony-stimulating factor (rhG-CSF) due to leuko-penia/neutropenia. When considering an ITT analysis, which included all patients regardless of rhG-CSF treatment, the BF839 group exhibited less reduction from baseline in white blood cells (-0.31±1.19 vs -1.15±0.77, p=0.012) and neutrophils (0.06±1.00 vs -0.84±0.85, p=0.004) compared to the placebo group. The difference became even more significant when excluding the patients who received rhG-CSF injections. Throughout the four treatment cycles, compared to the placebo group, the BF839 group had significantly lower rates of 3-4 grade nausea (35.0% vs 71.3%, p=0.001), vomiting (20.0% vs 45.0%, p=0.001), and diarrhea (15.0% vs 30.0%, p=0.023). CONCLUSIONS: These findings suggest that BF839 has the potential to effectively mitigate myelosuppression and gastrointestinal toxicity associated with chemotherapy in breast cancer patients.

Adsorption configurations and scanning voltage determined STM images of small hydrogen clusters on bilayer graphene.

By density functional theory calculations, the scanning tunneling microscopy (STM) images of various hydrogen clusters adsorbed on bilayer-graphene are systematically simulated. The hydrogen configurations of the STM images observed in the experiments have been thoroughly figured out. In particular, two kinds of hydrogen dimers (ortho-dimer, para-dimer) and two kinds of tetramers (tetramer-A, -B) are determined to be the hydrogen configurations corresponding to the ellipsoidal-like STM images with different structures and sizes. One particular hexamer (hexamer-B) is the hydrogen configuration generating the star-like STM images. For each hydrogen cluster, the simulated STM images show unique voltage-dependent features, which provides a feasible way to determine hydrogen adsorption states on graphene or graphite surface in the experiments by varying-voltage measurements. Stability analysis proves that the above determined hydrogen configurations are quite stable on graphene, hence they are likely to be detected in the STM experiments. Consequently, through systematic analysis of the STM images and the stability of hydrogen clusters on bilayer graphene, many experimental observations have been consistently explained.

Structures, stabilities, and electronic properties of defects in monolayer black phosphorus.

The structures, stabilities, and electronic properties of monolayer black phosphorus (M-BP) with different kinds of defects are investigated within the frame of density-functional theory. All the possible configurations of defects in M-BP are explored, and the calculated results suggest that the stabilities of the configurations with different kinds of defects are greatly related to broken bonds, structural deformation and the character of the bonding. The configurations with two or three vacancies are energetically more favorable than the ones with a single vacancy. Meanwhile, the doping of two foreign atoms, such as sulfur, silicon or aluminum, is more stable than that of the corresponding single dopant. The electronic properties of M-BP are greatly affected by the types of defects. The single S-doped M-BP not only retains the character of a direct semiconductor, but it also can enlarge the band gap by 0.24 eV relative to the perfect one. Such results reveal that the defects not only greatly affect the electronic properties, but they also can be used as an effective way to modulate the band gap for the different applications of M-BP in electronic devices.

Understanding and tuning the quantum-confinement effect and edge magnetism in zigzag graphene nanoribbon.

The electronic structure of zigzag graphene nanoribbon (ZGNR) is studied using density functional theory. The mechanisms underlying the quantum-confinement effect and edge magnetism in ZGNR are systematically investigated by combining the simulated results and some useful analytic models. The quantum-confinement effect and the inter-edge superexchange interaction can be tuned by varying the ribbon width, and the spin polarization and direct exchange splitting of the edge states can be tuned by varying their electronic occupations. The two edges of ZGNR can be equally or unequally tuned by charge doping or Li adsorption, respectively. The Li adatom has a site-selective adsorption on ZGNR, and it is a nondestructive and memorable approach to effectively modify the edge states in ZGNR. These systematic understanding and effective tuning of ZGNR electronics presented in this work are helpful for further investigation and application of ZGNR and other magnetic graphene systems.