New Karyotype Information for Ctenomys (Rodentia: Ctenomyidae) from Midwest and Northern Brazil.

INTRODUCTION: Its wide karyotypic variation characterizes the genus Ctenomys, and in Brazil, the genus is distributed in the country's southern, Midwest, and northern regions. Recently, populations of Ctenomys have been found in the Midwest and northern Brazil, with two new lineages named C. sp. "xingu" and C. sp. "central." METHODS: This work combines classical cytogenetic and molecular analyses to provide new chromosomal information on the boliviensis group distributed in northern and Midwestern Brazil. This includes the validation of the karyotype of C. bicolor and C. nattereri and the description of the karyotype of C. sp. "xingu" and C. sp. "central." RESULTS: We found three different karyotypes: 2n = 40 for C. bicolor; 2n = 36 for C. nattereri, and specimens from a locality belonging to C. sp. "central"; 2n = 34 for the lineage C. sp. "xingu" and specimens from a locality belonging to C. sp. "central." Furthermore, GTG banding revealed homologous chromosomes between species/lineages and allowed the identification of the rearrangements that occurred, which proved the occurrence of fissions. CONCLUSION: Considering our results on the variation of 2n in the boliviensis group, we found two possibilities: the first, deduced by parsimony, is that 2n = 36 appeared initially, and two fissions produced gave rise to 2n = 40, and an independent fusion gave rise to 2n = 34 from 2n = 36; moreover, the second explanation is that all karyotypes arose independently.

G band enhancement in ABt-twisted trilayer graphene.

G band, originating from the in-plane vibrations of carbon atoms, is the main signature in Raman spectroscopy of graphene-based systems. It is often used to characterize the sample quality and obtain molecular vibration information. Here we investigate the Raman spectroscopy of ABt-twisted trilayer graphene (ABt-TTG) and observe two enhancement centers for the G band across samples with different twist angles. To understand the origin of these two enhancement centers, we theoretically calculate the G band intensity of ABt-TTG based on the continuum model. We find that the theoretical calculations exhibit two prominent peaks corresponding to the experimental observations after Fermi velocity corrections. We also investigated the real and imaginary parts of Raman resonances, respectively, and explained the origins of two enhancements of ABt-TTG. By using Raman spectroscopy, evolutions of band structures of ABt-TTG with respect to the twist angles can be characterized, which extends the potential applications of the Raman method in the investigation of electronic structures of graphene-based systems.

Effect of Prolonged Photoperiod on Light-Dependent Photosynthetic Reactions in Cannabis.

Industrial hemp is a fast-growing, short-day plant, characterized by high biomass yields and low demands for cultivation. To manipulate growth, hemp is usually cultivated under prolonged photoperiods or continuous light that could cause photooxidative damage and adjustments of photosynthetic reactions. To determine the extent of changes in photosynthetic response caused by prolonged light exposure, we employed chlorophyll a fluorescence measurements accompanied with level of lipid peroxidation (TBARS) and FT-IR spectroscopy on two Cannabis cultivars. Plants were grown under white (W) and purple (P) light at different photoperiods (16/8, 20/4, and 24/0). Our results showed diverse photosynthetic reactions induced by the different light type and by the duration of light exposure in two cultivars. The most beneficial condition was the 16/8 photoperiod, regardless of the light type since it brought the most efficient physiological response and the lowest TBARS contents suggesting the lowest level of thylakoid membrane damage. These findings indicate that different efficient adaptation strategies were employed based on the type of light and the duration of photoperiod. White light, at both photoperiods, caused higher dissipation of excess light causing reduced pressure on PSI. Efficient dissipation of excess energy and formation of cyclic electron transport around PSI suggests that P20/4 initiated an efficient repair system. The P24/0 maintained functional electron transport between two photosystems suggesting a positive effect on the photosynthetic reaction despite the damage to thylakoid membranes.

The Karyotype of Blainville's Beaked Whale, Mesoplodon densirostris.

The karyotype of the Odontocete whale, Mesoplodon densirostris, has not been previously reported. The chromosome number is determined to be 2n = 42, and the karyotype is presented using G-, C-, and nucleolar organizer region (NOR) banding. The findings include NOR regions on 2 chromosomes, regions of heterochromatic variation, a large block of heterochromatin on the X chromosome, and a relatively large Y chromosome. The karyotype is compared to published karyograms of 2 other species of Mesoplodon.

Tension-Induced Raman Enhancement of Graphene Membranes in the Stretched State.

The intensity ratio of the 2D band to the G band, I2D /IG , is a good criterion in selecting high quality monolayer graphene samples; however, the evaluation of the ultimate value of I2D /IG for intrinsic monolayer graphene is a challenging yet interesting issue. Here, an interesting tension-induced Raman enhancement phenomenon is reported in supported graphene membranes, which show a transition from the corrugated state to the stretched state in the vicinity of wells. The I2D /IG of substrate-supported graphene membranes near wells are significantly enhanced up to 16.74, which is the highest experimental value to the best of knowledge, increasing by more than 600% when the testing points approach the well edges.The macroscopic origin of this phenomenon is that corrugated graphene membranes are stretched by built-in tensions. A lattice dynamic model is proposed to successfully reveal the microscopic mechanism of this phenomenon. The theoretical results agree well with the experimental data, demonstrating that tensile stresses can depress the amplitude of in-plane vibration of sp2 -bonded carbon atoms and result in the decrease in the G band intensity. This work can be helpful in furthering the development of the method of suppressing small ripples in graphene and acquiring ultraflat 2D materials.

Clinical features of diffuse large B-cell lymphoma with polyploidy.

Polyploidy, defined as more than two sets of homologous chromosomes, is found in a variety of malignant tumors and is thought to be related to disease pathogenesis. However, there have been no studies that have investigated polyploidy in diffuse large B-cell lymphoma (DLBCL). Here we reviewed clinicopathological features of 16 cases of DLBCL with polypoidy, which was defined as DLBCL with either near-tetraploid or greater number of chromosomes as detected by the G-band method. The frequency of polyploid DLBCL was 2.9 % (16/544), including 15 near-tetraploid and one near-pentaploid case. CD5, CD30 and EBER positive cases were 13 % (2/16), 13 % (2/16) and 6 % (1/16), respectively. Bcl2 positive cases were 75 % (12/16). The numbers of huge and multinucleated cells were higher in polyploid than in non-polyploid DLBCL (P = 0.0029 and P < 0.0001, respectively). Clinical features of polyploid DLBCL included reduced infiltration of extranodal sites (2/15, 13 %) and major lymph node infiltration. Of seven cases that received chemotherapy, six responded to treatment and survived. Our results suggest that polyploid DLBCL represents a clinicopathologically characteristic group of DLBCL. This knowledge can be useful for informing more personalized and targeted management of DLBCL patients.

Strategic development and performance evaluation of functionalized tea waste ash-clay composite as low-cost, high-performance separator in microbial fuel cell.

The separator is an important component of the microbial fuel cells (MFCs), which separates anode and cathode entities and facilitates ion transfer between both. Despite the high research in separators in recent years, the need for cost-effective, waste-driven selective separators in MFCs persists. Present study discloses the strategic fabrication of functionalized-tea-waste-ash-clay (FTWA-C) composite separator by integrating functionalized tea waste ash (FTWA) with potter's clay. Clay was used as a base, while FTWA was used as cation exchanger. FTWA and clay were separately mixed in four different ratios, 00:100 (C1); 05:95 (C2); 10:90 (C3); 15:85 (C4). Mixtures were then crafted manually as consecutive four layers. C1-side faced anode while separator-cathode-assembly was developed at C4. The separator was characterized by evaluating proton and oxygen transfer coefficient, and water-uptake analysis. The separator was also analysed for elemental composition, microstructure, particle size, and surface area and porous structure. SEM analysis of FTWA showed the presence of 15-100 nm pores. EDS analysis of the FTWA-C showed the presence of hygroscopic oxides, mainly SO42- and SiO2. A slight peak observed at P/Po∼1, confirmed the presence of macropores. The FTWA-C separator showed proton transfer coefficient as high as 18.7 × 10-5 cm/s, and oxygen mass transfer coefficient of 2.1 × 10-4 cm/s. The FTWA-C displayed the highest operating voltage of 612.4.2 mV, the power density of 1.81 W/m3, and COD removal efficiency of 87.52%. The fabrication cost of this separator was estimated to be $9.8/m2. FTWA-C could be an affordable and high-efficiency alternative for expensive ion-exchange membranes in MFCs.

Insight into magnesium ions effect on chromosome banding and ultrastructure.

Magnesium ion (Mg2+ ) plays a fundamental role in chromosome condensation which is important for genetic material segregation. Studies about the effects of Mg2+ on the overall chromosome structure have been reported. Nevertheless, its effects on the distribution of heterochromatin and euchromatin region have yet to be investigated. The aim of this study was to evaluate the effects of Mg2+ on the banding pattern and ultrastructure of the chromosome. Chromosome analysis was performed using the synchronized HeLa cells. The effect of Mg2+ was evaluated by subjecting the chromosomes to three different solutions, namely XBE5 (containing 5 mM Mg2+ ) as a control, XBE (0 mM Mg2+ ), and 1 mM EDTA as cations-chelator. Chromosome banding was carried out using the GTL-banding technique. The ultrastructure of the chromosomes treated with and without Mg2+ was further obtained using SEM. The results showed a condensed chromosome structure with a clear banding pattern when the chromosomes were treated with a buffer containing 5 mM Mg2+ . In contrast, chromosomes treated with a buffer containing no Mg2+ and those treated with a cations-chelator showed an expanded and fibrous structure with the lower intensity of the banding pattern. Elongation of the chromosome caused by decondensation resulted in the band splitting. The different ultrastructure of the chromosomes treated with and without Mg2+ was obvious under SEM. The results of this study further emphasized the role of Mg2+ on chromosome structure and gave insights into Mg2+ effects on the banding distribution and ultrastructure of the chromosome.

A G-Band Broadband Continuous Wave Traveling Wave Tube for Wireless Communications.

Development of a G-band broadband continuous wave (CW) traveling wave tube (TWT) for wireless communications is described in this paper. This device provides the saturation output power over 8 W and the saturation gain over 30.5 dB with a bandwidth of 27 GHz. The maximum output power is 16 W and the bandwidth of 10 W output power is 23 GHz. The 3 dB bandwidth is greater than 12.3% of fc (center frequency). The gain ripple is less than 10 dB in band. A pencil beam of 50 mA and 20 kV is used and a transmission ratio over 93% is realized. The intercept power of the beam is less than 70 W and the TWT is conduction cooled through mounting plate and air fan, which makes the device capable of operating in continuous wave mode. A Pierce's electron gun and periodic permanent magnets are employed. Chemical vapor deposition diamond disc is used in the input and output radio frequency (RF) windows to minimize the loss and voltage standing wave ratios of the traveling wave tube. Double stages deeply depressed collector is used for improving the total efficiency of the device, which can be over 5.5% in band. The weight of the device is 2.5 kg, and the packaged size is 330 mm × 70 mm × 70 mm.

A comparative analysis of the karyotypes of three dolphins - Tursiops truncatus Montagu, 1821, Tursiops australis Charlton-Robb et al., 2011, and Grampus griseus Cuvier, 1812.

The aim of this study is to produce G-banded karyotypes of three dolphin species, Tursiops truncatus Montagu, 1821, Tursiops australisCharlton-Robb et al., 2011, and Grampus griseus Cuvier, 1812, and to determine if any differences between the species can be observed. Monolayer skin cultures were established and processed for chromosome study by trypsin banding. The results indicate that the three species here investigated have the same diploid number (2n = 44) and very similar gross chromosome morphology, however G-banding allows distinction between each species. Chromosome 1 in G. griseus is significantly different from the other 2 species, and chromosome 2 in T. australis is subtly different from the other 2 species. This result is of potential significance in taxonomic studies, and can provide an unequivocal answer in the assessment of suspected hybrids between these species.