Construction of dPCR and qPCR integrated system based on commercially available low-cost hardware.

Fluorescent quantitative PCR (qPCR) and digital PCR (dPCR) are two mainstream nucleic acid quantification technologies. However, commercial dPCR and qPCR instruments have a low integration, a high price, and a large footprint. To solve these shortcomings, we introduce a compound PCR system with both qPCR and dPCR functions. All the hardware used in this compound PCR system is commercially available and low-cost, and free software was used to realize the absolute quantification of nucleic acids. The compound PCR provides two working modes. In the qPCR mode, thermal cycling is realized by controlling the reciprocating motion of the x axis. The heating rate is 1.25 °C s-1 and the cooling rate is 1.75 °C s-1. We performed amplification experiments of the PGEM-3zf (+)1 gene. The performance level was similar to commercial qPCR instruments. In the dPCR mode, the heating rate is 0.5 °C s-1 and the cooling rate is 0.6 °C s-1. We performed the UPE-Q gene amplification and used the sequential actions of the two-dimensional mechanical sliders to scan the reaction products and used the method of regional statistics and back-inference threshold to get test results. The result we got was 1208 copies per µL-1, which was similar to expectations.

Battery-Powered Portable Rotary Real-Time Fluorescent qPCR with Low Energy Consumption, Low Cost, and High Throughput.

The traditional qPCR instrument is bulky, expensive, and inconvenient to carry, so we report a portable rotary real-time fluorescent PCR (polymerase chain reaction) that completes the PCR amplification of DNA in the field, and the reaction can be observed in real-time. Through the analysis of a target gene, namely pGEM-3Zf (+), the gradient amplification and melting curves are compared to commercial devices. The results confirm the stability of our device. This is the first use of a mechanical rotary structure to achieve gradient amplification curves and melting curves comparable to commercial instruments. The average power consumption of our system is about 7.6 W, which is the lowest energy consumption for real-time fluorescence quantification in shunting PCR and enables the use of our device in the field thanks to its self-contained power supply based on a lithium battery. In addition, all of the equipment costs only about 710 dollars, which is far lower than the cost of a commercial PCR instrument because the control system through mechanical displacement replaces the traditional TEC (thermoelectric cooler) temperature control. Moreover, the equipment has a low technical barrier, which can suit the needs of non-professional settings, with strong repeatability.

An assessment system for evaluating the severity of thoracolumbar osteoporotic fracture and its clinical application: A retrospective study of 381 cases.

OBJECTIVE: We put forward an assessment system of thoracolumbar osteoporotic fracture (ASTLOF) evaluating the severity of thoracolumbar osteoporotic fracture. This study was to investigate its efficacy in guiding clinical practice. METHODS: Three hundred and eighty-one patients with thoracolumbar vertebral osteoporosis fracture admitted to the hospital from January 2010 to December 2011 were enrolled in the study. All cases were evaluated by ASTLOF including evaluation of morphological changes, MRI, bone mineral density and pain. The patients were treated with different methods according to ASTLOF score. All patients were followed up on a regular basis. The treatment results were assessed by VAS and ODI. RESULTS: All patients were followed up with an average of 20.1 (range: 6-30) months. There were 91 cases of ASTLOF score<4 points. Their average VAS score decreased from 8.0 ± 1.7 points to 2.0 ± 1.3 with statistical significance (P<0.05) and the average ODI score decreased from 69.5 ± 2.8 to 38.1 ± 1.5 (P<0.05). One hundred and thirty-two cases were with ASTLOF score=4, with the average VAS score decreased from 8.2 ± 1.4 to 1.9 ± 1.2 (P<0.05) and the average ODI score decreased from 71.5 ± 3.7 to 36.2 ± 2.5 (P<0.05). There were 158 cases of ASTLOF score ≥ 5, with the VAS score decreased from 8.0 ± 1.7 to 2.0 ± 1.3 and the ODI score decreased from 69.5 ± 2.8 to 38.1 ± 1.5. CONCLUSIONS: ASTLOF based on the severity of thoracolumbar osteoporotic fracture was suggested to be helpful in guiding clinical practice.

Solvation in electrospray mass spectrometry: effects on the reaction kinetics of fragmentation mediated by ion-neutral complexes.

In electrospray ionization (ESI) on a triple quadrupole mass spectrometer, benzydamine, a molecule with an N,N-dimethylaminopropoxyl side chain, showed a fragmentation pattern in Q1 scans that is dramatically different from the mass-selected collision-induced dissociation (CID) of its MH(+) ion. The N,N-dimethylimmonium ion, which dominates in Q1 scans at higher energies, is only a minor product in all CID spectra. By using a smaller model molecule, N,N,N',N'-tetramethyl-1,3-propanediamine, with the kinetic energy release measured for the corresponding reaction, we have demonstrated that an ion-neutral complex composed of the N,N-dimethylazetidine cation and a neutral counterpart is involved. When the ion-neutral complex intermediate evolves toward elimination to form the immonium ion, the transition state is stabilized by the neutral species. Solvation of the ion-neutral complex, which obstructs the separation of the two partners by the resulting tighter enclosure, facilitates the elimination by enhancing the stabilization of the transition state. Therefore, the prevalence of the immonium ion in Q1 scans was a result of solvation in the ESI source. In CID reactions, where the decomposing ions are mass-selected and thus solvation does not exist, the immonium ion was a minor product, and the separation of the ion-neutral complex became dominant.