Structures, electronic and thermodynamic properties of NiB2n (n=7-11) and their anions: A theoretical study

Based on the Crystal structure Analysis by Particle Swarm Optimization (CALYPSO) searching method and density functional theory (DFT), theoretical studies about structures, electronic and thermodynamic properties have been investigated systematically at the TPSSh/6-311+G(d) level for NiB2n0/- (n=7-11) clusters. Results found that the lowest energy structures possess a Ni atom-centered double ring tubular boron structures, NiB180/- except. Relative stabilities were analyzed via computing their vertical ionization potentials (VIP), vertical electronic affinity (VEA), adiabatic electronic affinity (AEA), HOMO-LUMO gaps and hardness. The infrared spectra, Raman spectra and photoelectron spectra were computationally simulated to facilitate their experimental characterizations. At last, aromatic properties (Nucleus independent chemical shift) and thermodynamic properties (enthalpy and entropy) with temperature were discussed in detailed for studied systems.

Super-resolved 3D Tracking of Cargo Transport Through Nuclear Pore Complexes by Astigmatism Imaging

This protocol describes a two-color astigmatic imaging approach that enables direct 3D visualization of cargo transport trajectories relative to a super-resolved octagonal double-ring scaffold structure of the nuclear pore complex (NPC). Though astigmatism imaging is commonly achieved via a cylindrical lens, this protocol utilizes an adaptive optics (AO) system, which enables optimization of the astigmatism for the precision needs of the experiment as well as correction of the focal mismatch arising from chromatic aberrations in multi-color applications. With this approach, single particle spatial precision values in x, y, and z are typically 5-20 nm, and these depend on astigmatism, photon level and position in z. The method enables resolution of transport conduits through the ~60 nm diameter pore of NPCs by particle tracking on the millisecond timescale. The success of this approach is enabled by the high rigidity of fully active NPCs within the nuclear envelope of permeabilized cells. For a detailed application of this protocol, please refer to https://www.nature.com/articles/s41556-021-00815-6. The figure and table numbers in this protocol that are indicated with an “NCB” prefix (e.g., NCB Figure X) refer to the figures and table in this reference paper.

Formation and Evolution of sp2 Hybrid Conjugate Structure of Polyacrylonitrile Precursor during Stabilization

The generated sp2 hybrid conjugate structure of a C atom, which resulted from the chemical reaction affected by temperature and time, is an effective six-membered ring planar structure of the final carbon fiber. This kind of hybrid conjugate structure determined the formation of the final structure and mechanical properties of carbon fiber. In this paper, the formation and evolution of sp2 hybrid conjugated structures of PAN precursor during thermal stabilization were investigated by Raman, UV-vis and 13C-NMR methods. The results indicated that with the increase of stabilization temperature, the degree of the sp2 hybrid conjugated structure of stabilized PAN fiber increases “linearly”, while the content of the sp2 hybrid carbon atoms increases with “S-type”. The final sp2 hybrid conjugated ring structure is mainly composed of single-ring, double-ring, triple-ring, and double-bond structures. Compared with the time factor, the temperature effect plays a decisive role in the formation of the sp2 hybrid conjugate structure.

Hydraulic Conductivity Testing and Destructive Sampling of Field-Scale Mine Waste Test Piles

A commingled waste rock and tailings test pile and a waste rock test pile were evaluated to determine saturated hydraulic conductivity and destructively sampled to measure dry density. The commingled test pile contained a mixture of filtered tailings and waste rock blended to isolate waste rock particles as inclusions within the tailings matrix. Test piles were constructed in the shape of truncated 5-m tall pyramids with 25-m base sides and flat 5-m × 5-m top surfaces, and instrumented to monitor water content (and additional geochemical indicator parameters) within the test pile and seepage from the base of the pile. Piles were decommissioned after 26 months of operation. Saturated hydraulic conductivities were measured using sealed double ring infiltrometers (2.4-m square outer-ring and 1-m square inner-ring). Tensiometers and embedded water content sensors were used to measure progression of the wetting front, and the final location of the wetting front in the commingled test pile was directly measured during decommissioning. Field-measured saturated hydraulic conductivities were compared to laboratory-measured results intended to simulate the test piles. Despite having a lower average density, the commingled waste rock and tailings had a hydraulic conductivity approximately 2.5-times lower than the waste rock.

Ponding time in infiltration process for different land use

Ponding time is the period from the beginning of rainfall/infiltration until the occurrence of ponding. This paper aims to determine the infiltration rate and ponding time on different land uses, such as open fields, residential, agriculture, and vegetation. This research was conducted in one of the watersheds in the Brantas River Basin, namely the Lesti River Basin, which is administratively included in the Malang Regency, East Java. The Lesti River is one of the tributaries of the Brantas River, which originates around Mount Semeru, a very intensive area for planting rice, sugar cane, and coffee. Infiltration data were collected at 35 points using a double-ring infiltrometer spread across the Lesti watershed with Andosol, Mediterranean, and Regosol soil types. At the same time, ponding time was obtained from infiltration measurements in the field using the flooding method. The physical properties of the soils were tested in the laboratory to obtain water content, porosity, and bulk density values. This study resulted in the infiltration rate and ponding time for each land use and shows how the physical properties of the soil affect the ponding time.

Study on behavior of ponding time based on characteristics of infiltration rate and rainfall intensity with varying return period

Runoff management is based on two main concepts: controlling runoff discharge and managing concentration (Tc). Tc is closely related to understanding ponding time (tp), which is associated with estimating the length of tp on a land surface. The present study aims to investigate the behavior of tp due to varying infiltration rates (f) and rainfall intensities (i) with different return periods (Tr). The ponding time (tp) was derived from graph analysis of infiltration rate and rainfall intensity with Tr 2, 5, and 10 years. Infiltration measurements were conducted at 8 points using a double-ring infiltrometer. Meanwhile, rainfall data were obtained from 2010 to 2019. The observed tp (tpobs ) was derived through overlying between infiltration rate curve and rainfall intensity. In contrast, empirical tp (tpemp ) was estimated using Horton’s formula. The result confirms that the infiltration rate followed an exponential curve and varying rainfall intensities. Infiltration rates give vary in tp where the longer Tr, the faster the initial time of tp. There was fairly good consistency between tpobs and tpemp as shown by relatively high-value R2 >0.6) for Tr 2, 5, and 10 years. It indicates that the Horton’s formula has reliable to estimate tp in the study area.

Septin Assembly and Remodeling at the Cell Division Site During the Cell Cycle

The septin family of proteins can assemble into filaments that further organize into different higher order structures to perform a variety of different functions in different cell types and organisms. In the budding yeast Saccharomyces cerevisiae, the septins localize to the presumptive bud site as a cortical ring prior to bud emergence, expand into an hourglass at the bud neck (cell division site) during bud growth, and finally “split” into a double ring sandwiching the cell division machinery during cytokinesis. While much work has been done to understand the functions and molecular makeups of these structures, the mechanisms underlying the transitions from one structure to another have largely remained elusive. Recent studies involving advanced imaging and in vitro reconstitution have begun to reveal the vast complexity involved in the regulation of these structural transitions, which defines the focus of discussion in this mini-review.