The science of uncertainty

The disruption caused by the coronavirus pandemic has now affected most aspects of life for an immense proportion of the world. From health to economics, jobs, moods, routines and communication, everything has been touched by a tiny 200 nanometer particle consisting of only a single piece of RNA and its envelope. Among these changes, science has acquired an unprecedented level of attention from outside its own community. Those who might have never even heard the words “genetic material”, became suddenly eager to learn about viruses, the immune system and vaccine development. Nevertheless, being in the loop does not come free of responsibility or criticism, and we now encounter the need to put this new found interaction between scientists and the general public into perspective.

Study on Preparation and Application of Protein Filler by Chitosan Modified Keratin

In order to make rational use of waste cattle hair, the protein filler was prepared by using chitosan modified keratin which hydrolyzed waste cattle hair, then used in retanning and filling process. The optimal modification conditions of keratin: chitosan: keratin was 20:80, pH value was 2, time was 5h, chitosan modified keratin product zeta potential was 31.3mV, nanometer particle size was 482d·nm. Chitosan-modified keratin can be used as chrome auxiliaries in the retanning process to significantly reduce total chromium in the waste liquid. At the same time, the modified keratin had good filling performance. Moreover, the softness, tearing force and tensile strength of the shoe upper leather which filled with chitosan modified keratin were improved.

Structured Back Focal Plane Interferometry (SBFPI)

Back focal plane interferometry (BFPI) is one of the most straightforward and powerful methods for achieving sub-nanometer particle tracking precision at high speed (MHz). BFPI faces technical challenges that prohibit tunable expansion of linear detection range with minimal loss to sensitivity, while maintaining robustness against optical aberrations. In this paper, we devise a tunable BFPI combining a structured beam (conical wavefront) and structured detection (annular quadrant photodiode). This technique, which we termed Structured Back Focal Plane Interferometry (SBFPI), possesses three key novelties namely: extended tracking range, low loss in sensitivity, and resilience to spatial aberrations. Most importantly, the conical wavefront beam preserves the axial Gouy phase shift and lateral beam waist that can then be harnessed in a conventional BFPI system. Through a series of experimental results, we were able to tune detection sensitivity and detection range over the SBFPI parameter space. We also identified a figure of merit based on the experimental optimum that allows us to identify optimal SBPFI configurations that balance both range and sensitivity. In addition, we also studied the resilience of SBFPI against asymmetric spatial aberrations (astigmatism of up to 0.8 λ) along the lateral directions. The simplicity and elegance of SBFPI will accelerate its dissemination to many associated fields in optical detection, interferometry and force spectroscopy.

A Simple and Rapid Phosphorescence Probe Based on Mn-Doped ZnS Quantum Dots for Chloramphenicol Detection

An innovative phosphorescence probe based on Mn-doped ZnS quantum dots (Mn:ZnS QDs) was developed for selective detection of chloramphenicol (CAP) via inner-filter effect (IFE). Mn:ZnS QDs were synthesized by water method and modified with L-Cysteine for better stability, and the average diameter of the nanometer particle was 3.8[Formula: see text]nm. With the excitation wavelength at 289[Formula: see text]nm, the strong phosphorescence of Mn:ZnS QDs can be emitted at 583[Formula: see text]nm. The excitation spectrum of Mn:ZnS QDs was substantially overlapped with the absorption spectrum of the target CAP. The excited light of Mn:ZnS QDs can be absorbed partially by CAP when they coexist, the phosphorescence intensity decreased with the increasing concentration of CAP, and it has a good linear relationship. Under optimal conditions, the linear relational concentration range achieved four orders of magnitude from 25 to [Formula: see text] ([Formula: see text]), with a detection limit (LOD; [Formula: see text]) down to 0.81[Formula: see text][Formula: see text]. The simple, rapid and low cost IFE phosphorescent probe exhibited satisfactory recoveries ranging from 88.9% to 98.5% for CAP analysis in spiked honey, which shows a potential for routine screening of CAP in ensuring the food safety.

Research on the Preparation and Properties of UV-Curable Organic Silicon Nanomaterials

New organic silicon nano-materials which has photo-curing performance was prepared by sol-gel method using γ-methacryloxy propylt rimethoxy silane as the starting materials. The micro-structures of the organic silicon nano-materials were characterized by FTIR and NMR. TEM was used to observe the nanometer particle size and the distribution of the nanometer particle in the organic silicon nanomaterials. The photo-curing properties of the new materials were tested. Results show that the new organic silicon nano-materials has uniform particle distribution and side chain of methacryloxy groups and can be UV-curing.

The Research of Nanoparticle and Microparticle Hydroxyapatite Amendment in Multiple Heavy Metals Contaminated Soil Remediation

It was believed that when hydroxyapatite (HAP) was used to remediate heavy metal-contaminated soils, its effectiveness seemed likely to be affected by its particle size. In this study, a pot trial was conducted to evaluate the efficiency of two particle sizes of HAP: nanometer particle size of HAP (nHAP) and micrometer particle size of HAP (mHAP) induced metal immobilization in soils. Both mHAP and nHAP were assessed for their ability to reduce lead (Pb), zinc (Zn), copper (Cu), and chromium (Cr) bioavailability in an artificially metal-contaminated soil. The pakchoi (Brassica chinensisL.) uptake and soil sequential extraction method were used to determine the immobilization and bioavailability of Pb, Zn, Cu, and Cr. The results indicated that both mHAP and nHAP had significant effect on reducing the uptake of Pb, Zn, Cu, and Cr by pakchoi. Furthermore, both mHAP and nHAP were efficient in covering Pb, Zn, Cu, and Cr from nonresidual into residual forms. However, mHAP was superior to nHAP in immobilization of Pb, Zn, Cu, and Cr in metal-contaminated soil and reducing the Pb, Zn, Cu, and Cr utilized by pakchoi. The results suggested that mHAP had the better effect on remediation multiple metal-contaminated soils than nHAP and was more suitable for applying inin situremediation technology.

The Physical Essence of Mono-dispersed Nanometer Particle Surface Energy by Boundary bond Interaction

ABSTRACTThe surface energy quantifies the disruption of intermolecular bond that occurs when a surface is created. The paper discusses critical size dc of mono-dispersed nanometer particle by analyzing the change of interfacial surface energy. The traditional theory neglects that the mono-dispersed nanometer particle has quantum standing wave in its internal structure with a size below critical dc. During the preparation of mono-dispersed nanometer powder, the large surface energy is formed ont only by cutting surface bond but also by forming quantum standing wave that opposites to interfacial edge unsaturated bond on the nanometer partcile surface atom. The preparation process of nanometer material needs more energy than the size surpass dc material. The new theory can explain why the melting point of nanometer powder decreases and other phenomina of nanometer material.