Theoretical Analysis and Experimental Verification of the Influence of Polarization on Counter-Propagating Optical Tweezers.

Counter-propagating optical tweezers are experimental platforms for the frontier exploration of science and precision measurement. The polarization of the trapping beams significantly affects the trapping status. Using the T-matrix method, we numerically analyzed the optical force distribution and the resonant frequency of counter-propagating optical tweezers in different polarizations. We also verified the theoretical result by comparing it with the experimentally observed resonant frequency. Our analysis shows that polarization has little influence on the radial axis motion, while the axial axis force distribution and the resonant frequency are sensitive to polarization change. Our work can be used in designing harmonic oscillators which can change their stiffness conveniently, and monitoring polarization in counter-propagating optical tweezers.

A single-cell transcriptome atlas profiles early organogenesis in human embryos.

The early window of human embryogenesis is largely a black box for developmental biologists. Here we probed the cellular diversity of 4-6 week human embryos when essentially all organs are just laid out. On the basis of over 180,000 single-cell transcriptomes, we generated a comprehensive atlas of 313 clusters in 18 developmental systems, which were annotated with a collection of ontology and markers from 157 publications. Together with spatial transcriptome on embryonic sections, we characterized the molecule and spatial architecture of previously unappreciated cell types. Combined with data from other vertebrates, the rich information shed light on spatial patterning of axes, systemic temporal regulation of developmental progression and potential human-specific regulation. Our study provides a compendium of early progenitor cells of human organs, which can serve as the root of lineage analysis in organogenesis.

Analysis and Suppression of Laser Intensity Fluctuation in a Dual-Beam Optical Levitation System.

Levitated micro-resonators in vacuums have attracted widespread attention due to their application potential in precision force sensing, acceleration sensing, mass measurement and gravitational wave sensing. The optically levitated microsphere in a counter-propagating dual-beam optical trap has been of particular interest because of its large measurement range and flexible manipulation. In this system, laser intensity fluctuation directly influences the trap stability and measurement sensitivity, which makes it a crucial factor in improving trapping performance. In this paper, a time-varying optical force (TVOF) model is established to characterize the influence of laser intensity fluctuation in a dual-beam optical trap. The model describes the relationship between the laser intensity fluctuation, optical force and the dynamic motion of the micro-sized sphere. In addition, an external laser intensity control method is proposed, which achieved a 16.9 dB laser power stability control at the relaxation oscillation frequency. The long-term laser intensity fluctuation was suppressed from 3% to 0.4% in a one-hour period. Experiments showed that the particle's position detection sensitivity and the stability of the relaxation oscillation could be improved by laser intensity fluctuation suppression.

Could intracranial tumor volume predict prognosis of patients with brain metastases from esophageal carcinoma?

PURPOSE: A previous study demonstrated that intracranial tumor volume had some correlation with gastrointestinal cancer patients' outcome. The aim of this study was to analyze patients with esophageal carcinoma (EC) and brain metastases to investigate if intracranial tumor volume would be a predictor of these patients' survival. METHODS: A total of 52 patients with brain metastases from esophageal squamous cell carcinoma or esophageal adenocarcinoma were retrospectively reviewed. Patients without images of brain metastases in the hospital information system were eliminated. RESULTS: The median follow-up time duration was 8.4 months (interquartile range 4.0-15.2). The median overall survival (OS) from time of brain metastases diagnosis was 8.0 months for all cases. Median OS of patients with small and large cumulative intracranial tumor volume (CITV) (<6.65 cm3 , ≥6.65 cm3 ) was 11.23 and 7.4 months, respectively. Median OS of patients with large and small largest intracranial tumor volume (LITV) (≥7.75 cm3 , <7.75 cm3 ) was 6.4 and 10.6 months, respectively. Univariate analysis demonstrated that CITV (hazard ratio [HR] 1.255, 95% confidence interval [CI] 0.673-2.342, p = 0.475) or LITV (HR 1.037, 95% CI 0.570-1.887, p = 0.904) was not significantly associated with improved OS. Multivariate analysis demonstrated that CITV and LITV were not significantly associated with improved OS. CONCLUSION: EC patients with small intracranial tumor volume may have longer OS than those with large intracranial tumor volume, but this difference did not reach statistical difference. Future studies with a larger sample size may validate the correlation of intracranial tumor volume and patient survival.

3D calibration of microsphere position in optical tweezers using the back-focal-plane interferometry method.

This paper presents a method to directly calibrate the position of a trapped micro-sphere in optical tweezers utilizing its interference pattern formed at the back focal plane (BFP). Through finite difference time domain (FDTD) and scalar diffraction theorem, the scattering field complex amplitude of the near and far fields can be simulated after interference between the trapped sphere and focus Gaussian beam. The position of the trapped sphere can be recovered and calibrated based on a back focal plane interferometry (BFPI) algorithm. Theoretical results demonstrate that optical tweezers with a larger numerical aperture (NA) Gaussian beam will yield a better detection sensitivity but with a smaller linear range. These results were experimentally validated by trapping a microsphere in a single beam optical tweezer. We used an extra focused laser to manipulate the trapped sphere and then compared its position in the images and that obtained using the BFP method. The interference pattern from simulation and experiments showed good agreement, implying that the calibration factor can be deduced from simulation and requires no intermediate calculation process. These results provide a pathway to obtain the calibration factor, enable a faster and direct measurement of the sphere position, and show possibilities for adjusting the crosstalk and nonlinearity inside an optical trap.

Clinicopathological Features and Prognoses in Patients With Brain Metastases From Small-Cell Esophageal Carcinoma: A Retrospective Analysis of 18 Patients.

Objective: This study aims to examine the clinical characteristics of patients with brain metastases (BM) from small-cell esophageal carcinoma (SCEC) and to explore the association of the corresponding factors with overall survival (OS). Methods: The data of 18 patients with brain metastases from SCEC, diagnosed from January 1, 2006, to December 31, 2018, in the Fourth Hospital of Hebei Medical University were analyzed retrospectively. Results: The 18 patients who were included in this study accounted for 6.7% of the patients with SCEC diagnosed from 2006 to 2018. Of the 18 patients, 8 (44.4%) were females. For the entire cohort, the median OS was 7 months, the 1-year OS was 22.2%, and the 2-year OS was 0%. For patients who received whole-brain radiotherapy (WBRT) and for those who did not (13 vs. 5), the median OS was 11.9 and 3 months, respectively, and the 1-year OS was 30.8 and 0%, respectively. When comparing diagnosis-specific Graded Prognostic Assessment (DS-GPA) scores of patients with BM from SCEC ranging from 2.5 to 4 and from 0 to 2, the median OS was 13.1 and 4 months, respectively, and the 1-year OS was 57.1 and 0%, respectively. In the univariable regression, patients who received WBRT had improved OS compared to those who did not (HR = 0.249, p = 0.018), and patients with a DS-GPA score of 2.5-4 were associated with improved OS compared with patients with a DS-GPA score of 0-2 (HR = 0.050, p = 0.005). Conclusion: The incidence of brain metastases in patients with SCEC is low, but the prognosis in those patients is very poor. The DS-GPA score may be a prognostic factor of patients with BM from SCEC. Brain radiotherapy could improve the survival of these patients.

In-air self-reduction synthesis and luminescence properties from Mg21 Ca4 Na4 (PO4 )18 :Eu2+ -Eu3+ excited using ultraviolet light.

A series of Mg21 Ca4 Na4 (PO4 )18 :Eu2+ -Eu3+ phosphors was successfully synthesized using a high-temperature solid-state method in an air atmosphere. The phase structures and luminescence properties of the samples were studied in detail. The phosphors exhibited strong visible light emission under different wavelengths of ultraviolet light excitation. By harmonizing the doping concentration of Eu3+ to adjust the relative luminescence intensity of Eu2+ and Eu3+ , a colourful emission of phosphors could be achieved. In addition, the colour coordinates of the International Commission on lighting indicated that Mg21 Ca4 Na4 (PO)18 :Eu2+ -Eu3+ could be considered as a potential blue, orange and red phosphor for white light-emitting diode applications.

Self-reduction synthesis and luminescence properties of Eu, Dy co-doped SrMg2 (PO4 )2 phosphor.

A series of SrMg2 (PO4 )2 :Eu2+ -Eu3+ ,Dy3+ phosphors was synthesized successfully using a high-temperature solid-state method in an air atmosphere. The structures were studied in detail using X-ray diffraction (XRD) and the luminescence properties of the samples. SrMg2 (PO4 )2 :Eu2+ -Eu3+ samples can emit adjustable blue-violet light by controlling the proportion of dopant concentration of europium and dysprosium under 340 nm excitation. Dy3+ exhibits typical blue and yellow emission under 350 nm excitation. The energy transferred from Eu3+ to Dy3+ in Dy and Eu co-doped system was determined by comparing the fluorescence spectra of single-doped system. In addition, the colour coordinates of the International Commission on lighting (CIE) indicated that SrMg2 (PO4 )2 :Eu2+ -Eu3+ ,Dy3+ could be considered as a potential blue-purple phosphor for white light-emitting diode applications.

Broadband Absorption and Efficient Hot-Carrier Photovoltaic Conversion based on Sunlight-induced Non-radiative Decay of Propagating Surface Plasmon Polaritons.

Localized surface plasmon polaritons (SPPs), which can decay non-radiatively into hot carriers, have been widely employed to extend the responses of traditional semiconductor-based photocatalytic and photovoltaic devices to sub-bandgap photons. However, radiative decay is unavoidable and adverse to device performances. Here, we propose to take advantage of propagating SPPs, another form of SPPs, which possess non-radiative decay only. A special gold-titanium dioxide nanowire array with each nanowire capped with a nanocone is proposed. The adjacent nanocones forming top gradual openings attribute to efficient sunlight harvesting, while the neighbouring nanowires forming bottom nanoslots allow sufficient absorption due to the propagating SPPs. With the combined advantages, almost 100% of light is absorbed by a very thin gold film in the visible range, and 73% in the whole considered range of 400-1170 nm, superior to the nanocone cell based on localized SPPs, let alone the nanowire-based and planar counterparts. Therefore, much better photovoltaic conversion performance is achieved with short-circuit current density of 0.74 mA/cm2 and open-circuit voltage of 0.41 V. This work confirms the superiority of non-radiative decay of propagating SPPs to the localized SPPs in terms of generation of hot carriers, providing a promising way of extracting electrons in metal into photocurrent.

Genome editing reveals dmrt1 as an essential male sex-determining gene in Chinese tongue sole (Cynoglossus semilaevis).

Chinese tongue sole is a marine fish with ZW sex determination. Genome sequencing suggested that the Z-linked dmrt1 is a putative male determination gene, but direct genetic evidence is still lacking. Here we show that TALEN of dmrt1 efficiently induced mutations of this gene. The ZZ dmrt1 mutant fish developed ovary-like testis, and the spermatogenesis was disrupted. The female-related genes foxl2 and cyp19a1a were significantly increased in the gonad of the ZZ dmrt1 mutant. Conversely, the male-related genes Sox9a and Amh were significantly decreased. The dmrt1 deficient ZZ fish grew much faster than ZZ male control. Notably, we obtained an intersex ZW fish with a testis on one side and an ovary on the other side. This fish was chimeric for a dmrt1 mutation in the ovary, and wild-type dmrt1 in the testis. Our data provide the first functional evidence that dmrt1 is a male determining gene in tongue sole.

In Vitro Reconstitution and Optimization of the Entire Pathway to Convert Glucose into Fatty Acid.

Glucose and fatty acids play essential physiological roles in nearly all living organisms, and the pathway that converts glucose into fatty acid is pivotal to the central metabolic network. We have successfully reconstituted a pathway that converts glucose to fatty acid in vitro using 30 purified proteins. Through systematic titration and optimization of the glycolytic pathway and pyruvate dehydrogenase, we increased the yield of free fatty acid from nondetectable to a level that exceeded 9% of the theoretical yield. We also reconstituted the entire pentose-phosphate pathway of Escherichia coli and established a pentose phosphate-glycolysis hybrid pathway, replacing GAPDH to enhance NADPH availability. Our efforts provide a useful platform for research involving these core biochemical transformations.

Interferon regulatory factor 4b (IRF4b) in Japanese flounder, Paralichthys olivaceus: Sequencing, ubiquitous tissue distribution and inducible expression by poly(I:C) and DNA virus.

Interferon regulatory factor 4 (IRF4) in mammals is known to be critical in regulation of development and functions of lymphomyeloid cell lineages. Recent studies have demonstrated its involvement in immune responses to bacterial and viral challenges in teleosts. In this study, an IRF4 gene was cloned from Japanese flounder (Paralichthys olivaceus) and its expression in response to polyinosinic:polycytidylic acid [poly(I:C)] and lymphocystis disease virus (LCDV) stimulations was studied in vivo. The cloned gene spans over 5.9 kb, comprises eight exons and seven introns and encodes a putative protein of 456 amino acids. The deduced amino acid sequence possesses a conserved DNA-binding domain (DBD), an IRF-association domain (IAD) and a nuclear localization signal (NLS). Phylogenetic analysis clustered it into the teleost IRF4b clade and, thus, it was named Paralichthys olivaceus (Po)IRF4b. The constitutive expression of PoIRF4b transcripts was detectable in all examined organs, with highest levels found in lymphomyeloid-rich tissues. They were induced by both poly(I:C) and LCDV with a similar inducibility in immune or non-immune organs. Two waves of induced expression of PoIRF4b were observed with the two stimuli during a 7-day time course in the immune organs, with the early-phase induction being stronger. The maximum increases of PoIRF4b transcript levels ranged from 1.3 to 4.0-fold and appeared at day 1-5 post-injection depending on different organs and stimuli. In both stimulation cases, the strongest induction was detected in spleen and the weakest in muscle. These results indicate that PoIRF4b may participate in regulation of immune responses of flounders to both RNA and DNA virus infections.

In vitro reconstitution of mevalonate pathway and targeted engineering of farnesene overproduction in Escherichia coli.

Approaches using metabolic engineering and synthetic biology to overproduce terpenoids, such as the precursors of taxol and artemisinin, in microbial systems have achieved initial success. However, due to the lack of steady-state kinetic information and incomplete understanding of the terpenoid biosynthetic pathway, it has been difficult to build a highly efficient, universal system. Here, we reconstituted the mevalonate pathway to produce farnesene (a precursor of new jet fuel) in vitro using purified protein components. The information from this in vitro reconstituted system guided us to rationally optimize farnesene production in E. coli by quantitatively overexpressing each component. Targeted proteomic assays and intermediate assays were used to determine the metabolic status of each mutant. Through targeted engineering, farnesene production could be increased predictably step by step, up to 1.1 g/L (∼ 2,000 fold) 96 h after induction at the shake-flask scale. The strategy developed to release the potential of the mevalonate pathway for terpenoid overproduction should also work in other multistep synthetic pathways.