A regulatory role for the cohesin loader NIPBL in nonhomologous end joining during immunoglobulin class switch recombination.

DNA double strand breaks (DSBs) are mainly repaired via homologous recombination (HR) or nonhomologous end joining (NHEJ). These breaks pose severe threats to genome integrity but can also be necessary intermediates of normal cellular processes such as immunoglobulin class switch recombination (CSR). During CSR, DSBs are produced in the G1 phase of the cell cycle and are repaired by the classical NHEJ machinery. By studying B lymphocytes derived from patients with Cornelia de Lange Syndrome, we observed a strong correlation between heterozygous loss-of-function mutations in the gene encoding the cohesin loading protein NIPBL and a shift toward the use of an alternative, microhomology-based end joining during CSR. Furthermore, the early recruitment of 53BP1 to DSBs was reduced in the NIPBL-deficient patient cells. Association of NIPBL deficiency and impaired NHEJ was also observed in a plasmid-based end-joining assay and a yeast model system. Our results suggest that NIPBL plays an important and evolutionarily conserved role in NHEJ, in addition to its canonical function in sister chromatid cohesion and its recently suggested function in HR.

Allosteric regulation of the primase (DnaG) activity by the clamp-loader (τ) in vitro

During DNA replication the helicase (DnaB) recruits the primase (DnaG) in the replisome to initiate the polymerization of new DNA strands. DnaB is attached to the τ subunit of the clamp-loader that loads the β clamp and interconnects the core polymerases on the leading and lagging strands. The τ–DnaB−DnaG ternary complex is at the heart of the replisome and its function is likely to be modulated by a complex network of allosteric interactions. Using a stable ternary complex comprising the primase and helicase from Geobacillus stearothermophilus and the τ subunit of the clamp-loader from Bacillus subtilis we show that changes in the DnaB–τ interaction can stimulate allosterically primer synthesis by DnaG in vitro. The A550V τ mutant stimulates the primase activity more efficiently than the native protein. Truncation of the last 18 C-terminal residues of τ elicits a DnaG-stimulatory effect in vitro that appears to be suppressed in the native τ protein. Thus changes in the τ–DnaB interaction allosterically affect primer synthesis. Although these C-terminal residues of τ are not involved directly in the interaction with DnaB, they may act as a functional gateway for regulation of primer synthesis by τ-interacting components of the replisome through the τ–DnaB−DnaG pathway.

On loader productivity, rock strength and explosive energy in metal mining

Twenty production blasts in two open pit mines were monitored, in rocks with medium to very high strength. Three different blasting agents (ANFO, watergel and emulsion blend) were used, with powder factors ranging between 0.88 and 1.45 kg/m3. Excavators were front loaders and rope shovels. Mechanical properties of the rock, blasting characteristics and mucking rates were carefully measured. A model for the calculation of the productivity of excavators is developed thereof, in which the production rate results as a product of an ideal, maximum, productivity rate times an operating efficiency. The maximum rate is a function of the dipper capacity and the efficiency is a function of rock density, strength, and explosive energy concentration in the rock. The model is statistically significant and explains up to 92 % of the variance of the production rate measurements.

Admittance Control for Robotic Loading: Design and Experiments with a 1-Tonne Loader and a 14-Tonne LHD

This paper describes the design, tuning, and extensive field testing of an admittance-based Autonomous Loading Controller (ALC) for robotic excavation. Several iterations of the ALC were tuned and tested in fragmented rock piles—similar to those found in operating mines—by using both a robotic 1-tonne capacity Kubota R520S diesel-hydraulic surface loader and a 14-tonne capacity Atlas Copco ST14 underground load-haul-dump (LHD) machine. On the R520S loader, the ALC increased payload by 18 % with greater consistency, although with more energy expended and longer dig times when compared with digging at maximum actuator velocity. On the ST14 LHD, the ALC took 61 % less time to load 39 % more payload when compared to a single manual operator. The manual operator made 28 dig attempts by using three different digging strategies, and had one failed dig. The tuned ALC made 26 dig attempts at 10 and 11 MN target force levels. All 10 11 MN digs succeeded while 6 of the 16 10 MN digs failed. The results presented in this paper suggest that the admittance-based ALC is more productive and consistent than manual operators, but that care should be taken when detecting entry into the muck pile

Operator, organizational, direct support, and general support maintenance manual : loader, scoop type, DED, 4 wheel drive, pneumatic tired, hinged frame steer, 2 1/2 cu. yd. multi-purpose bucket (J.I. Case model MW-24), FSN 3805-253-0627.

"December 1970."

Direct support and general support maintenance manual for tractor, wheeled, DED, loader backhoe, with hydraulic impact tool and with hydraulic earth auger attachment, John Deere model JD410 (CCE), with bucket, impactor, and earth drill (NSN 2420-00-567-0135).

"August 1992."

Operator's manual : loader, scoop type, DED, 4x4, articulated frame steer, 2-1/2 cubic yard, (J.I. Case model MW24C), NSN 3805-01-150-4814).

Includes indexes.

Organizational maintenance repair parts and special tools list for loader-transporter, guided missile, M688A1 1450-01-133-4439 handling unit, guided missile equipment M39 1450-01-132-7715 hoisting unit, tripod M38 1450-00-937-0893 sling, beam type M22 1450-00-937-0894, Lance Field Artillery Missile System.

Includes index.

Direct support and general support maintenance repair parts and special tools list including depot maintenance repair parts and special tools for loader-transporter, guided missile, M688A1, 1450-01-133-4439, handling unit, guided missile equipment, M39, 1450-01-132-7715, hoisting unit, tripod, M38, 1450-00-937-0893, sling, beam type, M22, 1450-00-937-0894, Lance Field Artillery Missile System.

Includes index.

Operator and organizational maintenance manual, loader transporter M688, mobility kit M234, tripod hoist M38, sling beam M22, Lance Missile System.

"MS 419586."

Direct support and general support maintenance manual : loader-transporter, guided missile, XM501E3 (Hawk guided missile system), part number 11675300, NSN 1450-00-066-8873.

Includes index.

Operator's manual : loader-transporter, guided missile, XM501E3 (Hawk guided missile system) (1450-00-066-8873).

"March 1988."

Organizational maintenance manual : loader-transporter, guided missile, XM501E3 (Hawk guided missile system), part number 11675300, NSN 1450-00-066-8873).

"June 1979."

Operator's manual : tractor, wheeled (DED) loader backhoe w/hydraulic impact tool and w/hydraulic earth auger attachment, John Deere model JD410 (CCE), w/Wain-Roy Bucket, Hughes Impactor and Danuser Earth Drill, (NSN 2420-00-567-0135).

Includes index.