Pre-driven longwall recovery roadways are commonly adopted for rapid extraction in the high-production mines of Shendong coalfield in China. A special roadway, the adapting roadway, is utilized to adapt the longwall roof and floor to match the recovery roadway. However, severe accidents such as roof falls and support failures frequently occurred where this recovery roadways layout was applied to relatively deep coal seams. This posed a serious threat to safe production, and effective recovery and relocation of the longwalls. By analysing different cases and mining conditions, theoretical investigation and numerical simulation were conducted based on the mechanisms of such incidents, and a systematic control approach was proposed. The controls involve a method to determine the applicability of the adapting roadway, the evaluation of incident potential, the means to reduce the likelihood of incidents, and an optimized method to determine the location of mesh installation. The findings were applied to multiple longwall faces in the Shendong coalfield and resulted in substantial benefits. The study findings and the proposed control approach can also be applied to other mines with similar problems.

ABSTRACT Salmonella enterica subspecies enterica serotype Enteritidis (SE) has caused foodborne infections over decades. It is transmitted mainly from contaminated eggs to humans. SE is commonly present in layer houses, and closely interacts with environmental factors. The objective of the present study was to develop a viable PCR method to identify SE in environmental samples collected in layer farms of different sizes, and to evaluate SE contamination status in four main egg-production provinces of northern China. After specificity retrieval using Primer-BLAST against the NCBI database, three SE specific oligonucleotide primers were selected as candidate primers. The primers targeting Prot6e gene were adopted and primers targeting Sdf I were also selected to validate the results, after testing eight different types of pooled poultry environmental samples (overshoe, air, drinking nipple, feed, egg collection belt, eggshell, air inlet, and air outlet) by PCR. A PCR detection limit of 1 CFU/mL was determined using cell lysates from pure cultures. Testing time was less than 48 h. On-farm samples were collected from two layer farm sizes (one housing more than 50,000 layers, and the other, less than 50,000 layers) in each province. The applied PCR method was shown to be simple, inexpensive and effective for screening SE in a large amount of farm samples. The study identified only one SE-positive farm, which a large farm and where nine samples were found to be contaminated with SE: drinking nipples (3), egg collection belt (1), air inlet (1), air (1), overshoe (1) and eggshell (2).

Current studies find that degenerated cartilage endplates (CEP) of vertebrae, with fewer diffusion areas, decrease nutrient supply and accelerate intervertebral disc degeneration. Many more apoptotic cells have been identified in degenerated than in normal endplates, and may be responsible for the degenerated grade. Previous findings suggest that inhibition of apoptosis is one possible approach to improve disc regeneration. It is postulated that inhibition of CEP cell apoptosis may be responsible for the regeneration of endplates. Caspase-3, involved in the execution phase of apoptosis, is a candidate for regulating the apoptotic process. In the present study, CEP cells were incubated in 1% fetal bovine serum. Activated caspases were detected to identify the apoptotic pathway, and apoptosis was quantified by flow cytometry. Lentiviral caspase-3 short hairpin RNA (shRNA) was employed to study its protective effects against serum deprivation. Silencing of caspase-3 expression was quantified by reverse transcription-polymerase chain reaction and Western blots, and inhibition of apoptosis was quantified by flow cytometry. Serum deprivation increased apoptosis of rat CEP cells through activation of a caspase cascade. Lentiviral caspase-3 shRNA was successfully transduced into CEP cells, and specifically silenced endogenous caspase-3 expression. Surviving cells were protected by the downregulation of caspase-3 expression and activation. Thus, lentiviral caspase-3 shRNA-mediated RNAi successfully silenced endogenous caspase-3 expression, preventing inappropriate or premature apoptosis.