Hot air-assisted radio frequency drying of corn kernels: the effect on structure and functionality properties of corn starch.

Hot air (HA) drying caused quality damage of grains with long treatment time. Radio frequency (RF) heating as an emerging technology was applied to improve drying quality of cereals effectively. The effects of HA-RF drying (50 °C, 70 °C, 90 °C) of corn kernels on the morphology, structure, and physicochemical properties of starch were investigated and compared with HA drying. The surface of treated starch became rough, along with fragments and pores. Drying treatments increased the amylose content from 10.59 % to 23.88 % and the residual protein content of starch from 0.58 % to 1.23 %, and reduced the crystallinity from 31.95 % to 17.15 % and short-range order structures of starch from 0.918 to 0.868. The change of structures in turn resulted in the increase of pasting viscosity, gelatinization temperature, storage modulus and loss modulus. Furthermore, the HA-RF dried starch displayed stronger thermal stability, higher gelatinization degree and better gelation properties than the HA-treated starch at the same temperature. The data proved that the synergistic effects of HA and RF were more effective in modulating the starch structure and improving the functional characteristics of corn starch. This paper would like to provide potential reference for better application of HA-RF technologies to corn.

Rapid detection of Burkholderia cepacia complex carrying the 16S rRNA gene in clinical specimens by recombinase-aided amplification.

The Burkholderia cepacia complex (BCC) is a group of opportunistic pathogens, including Burkholderia cepacia, Burkholderia multivorans, Burkholderia vietnamiensis and Burkholderia ambifaria, which can cause severe respiratory tract infections and lead to high mortality rates among humans. The early diagnosis and effective treatment of BCC infection are therefore crucial. In this study, a novel and rapid recombinase-aided amplification (RAA) assay targeting the 16S rRNA gene was developed for BCC detection. The protocol for this RAA assay could be completed in 10 min at 39°C, with a sensitivity of 10 copies per reaction and no cross-reactivity with other pathogens. To characterize the effectiveness of the RAA assay, we further collected 269 clinical samples from patients with bacterial pneumonia. The sensitivity and specificity of the RAA assay were 100% and 98.5%, respectively. Seven BCC-infected patients were detected using the RAA assay, and three BCC strains were isolated from the 269 clinical samples. Our data showed that the prevalence of BCC infection was 2.60%, which is higher than the 1.40% reported in previous studies, suggesting that high sensitivity is vital to BCC detection. We also screened a patient with B. vietnamiensis infection using the RAA assay in clinic, allowing for appropriate treatment to be initiated rapidly. Together, these data indicate that the RAA assay targeting the 16S rRNA gene can be applied for the early and rapid detection of BCC pathogens in patients with an uncharacterized infection who are immunocompromised or have underlying diseases, thereby providing guidance for effective treatment.

X-ray enabled detection and eradication of circulating tumor cells with nanoparticles.

The early detection and eradication of circulating tumor cells (CTCs) play an important role in cancer metastasis management. This paper describes a new nanoparticle-enabled technique for integrated enrichment, detection and killing of CTCs by using magnetic nanoparticles and bismuth nanoparticles, X-ray fluorescence spectrometry, and X-ray radiation. The nanoparticles are modified with tumor targeting agents and conjugated with tumor cells through folate receptors over-expressed on cancer cells. A permanent micro-magnet is used to collect CTCs suspended inside a flowing medium that contains phosphate buffered saline (PBS) or whole blood. The characteristic X-ray emissions from collected bismuth nanoparticles, upon excitation with collimated X-rays, are used to detect CTCs. Results show that the method is capable of selectively detecting CTCs at concentrations ranging from 100-100,000 cells/mL in the buffer solution, with a detection limit of ≈ 100 CTCs/mL. Moreover, the dose of primary X-rays can be enhanced to kill the localized CTCs by radiation induced DNA damage, with minimal invasiveness, thus making in vivo personalized CTC management possible.