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The isomerization of xylose to xylulose is considered the most promising approach to initiate xylose bioconversion. Here, phylogeny-guided big data mining, rational modification, and ancestral sequence reconstruction strategies were implemented to explore new active xylose isomerases (XIs) for Saccharomyces cerevisiae . Significantly, 13 new active XIs for S. cerevisiae were mined or artificially created. Moreover, the importance of the amino-terminal fragment for maintaining basic XI activity was demonstrated. With the mined XIs, four efficient xylose-utilizing S. cerevisiae were constructed and evolved, among which the strain S. cerevisiae CRD5HS contributed to ethanol titers as high as 85.95 and 94.76 g/liter from pretreated corn stover and corn cob, respectively, without detoxifying or washing pretreated biomass. Potential genetic targets obtained from adaptive laboratory evolution were further analyzed by sequencing the high-performance strains. The combined XI mining methods described here provide practical references for mining other scarce and valuable enzymes.

Purpose: Patients with HER2-positive (HER2+) metastatic breast cancer (MBC) have poor prognoses. Pyrotinib has shown promising antitumor activity in MBC to improve progression-free survival (PFS). However, findings based on real-world data to analyze whether pyrotinib affects overall survival (OS) remain scarce. Experimental Design: This real-world study is an exploratory analysis of brain metastasis (BM) and the final update of our preceding study of 168 patients with HER2+ MBC. PFS, OS, tumor mutation burden (TMB), clinical benefit rate (CBR), and overall response rate (ORR) were analyzed. Results: Pyrotinib treatment led to a median PFS time of 8.00 months and a median OS of 19.07 months in the 168 participants. High TMB was associated with poor OS (P = 0.0072) and PFS (P = 0.0028). In the 39 patients with BM, the median PFS and OS were 8.67 and 13.93 months, respectively. The surgery/radiation (S/R) group of patients with BM had prolonged survival (PFS: 9.97 vs. 7.73 months P = 0.19; OS: 20.67 vs. 12.43 months P = 0.021) compared with the no surgery/no radiation group (NS/NR). The CBR was 58.6% (S/R) vs. 41.4% (NS/NR), while the ORR was 24.1% (S/R) vs. 31.0% (NS/NR). Conclusions: Pyrotinib shows promise as a novel pan-HER2 tyrosine kinase inhibitor (TKI) for the treatment of BM and should be evaluated further. Surgical or radiotherapy in combination with pyrotinib was found to statistically improve OS in our cohort. TMB could be an exploratory biomarker for predicting PFS and OS, but its clinical application still needs further verification.

The microstructure of green-emitting InGaN/GaN quantum well (QW) samples grown at different temperatures was studied using cross-section scanning transmission electron microscopy (STEM) and plan-view cathodoluminescence (CL). The sample with the lowest InGaN growth temperature exhibits microscale variations in the CL intensity across the sample surface. Using STEM analysis of such areas, the observed darker patches do not correspond to any observable extended defect. Instead, they are related to changes in the extent of gross-well width fluctuations in the QWs, with more brightly emitting regions exhibiting a high density of such fluctuations, whilst dimmer regions were seen to have InGaN QWs with a more uniform thickness.

The effects of varying concentrations of ferrocene and thiophene on the synthesis of carbon nanotubes (CNT) in a floating catalyst, flame-based reaction system were investigated. Pre-vapourised ethanol was used as CNT feedstock, and a surrounding premixed H2/air flames was used as the heat source. Samples of the synthesised material were collected and analysed using Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy to determine the properties of the collected CNT samples. Sulphur to iron mass ratios were varied from 0 up to 10.1, by changing the relative amounts of thiophene and ferrocene. The latter was found to have only a marginal effect on the improvement in the yield of CNTs, but led to enhanced yield of iron oxide nanoparticles. In comparison, the addition of sulphur exhibited an increase in the synthesis of CNTs as compared to iron oxide nanoparticles, including their number density and length. An optimum window of mass ratios mS/Fe at 0.1–2 was identified. A numerical model for the diffusion of species is coupled with an equilibrium chemical model for the resulting species to understand the mechanism of the synthesis process, showing the range of elemental proportion conditions and residence times favourable to high yield of CNTs.

Lack of cellobiose utilization capability for many microorganisms results in carbon source waste in lignocellulosic biorefinery. In this study, genes for cellobiose transport and hydrolysis were introduced to Saccharomyces cerevisiae synV, a semi-synthetic yeast with an inducible SCRaMbLE (Synthetic Chromosome Rearrangement and Modification by LoxPsym-mediated Evolution) system incorporated into its chromosome V, endowing cellobiose utilization capability to this strain. Thereafter, two evolved strains with 98.1% and 79.2% improvement, respectively, in cellobiose utilization rate were obtained through induced SCRaMbLE. Further studies suggested that the enhanced cellobiose utilization capability directly correlated with copy number increases of introduced genes and some chromosome structural variations. In particular, it was experimentally demonstrated for the first time that deletion of redox stress related gene MXR1 and ATP conversion related gene ADK2 contributed to enhanced cellobiose conversion. Thereafter, the effectiveness of MXR1 and ADK2 deletions was demonstrated in artificial hydrolysate and rice straw hydrolysate, respectively.

Growing green and amber emitting InGaN/GaN quantum wells in the zincblende, rather than the wurtzite,crystal phase has the potential to improve efficiency. However, optimisation of the emission efficiency of theseheterostructures is still required to compete with more conventional alternatives. Photoluminescence timedecays were used to assess how the quantum well width and number of quantum wells affect the recombinationrates, and temperature dependent photoluminescence was used to determine the factors affecting recombinationefficiency. The radiative recombination lifetime was found to be approximately 600 ps and to increaseweakly with well width, consistent with a change in the exciton binding energy. The relative efficiency atroom temperature was found to increase by a factor of five when the number of wells was increased fromone to five. Furthermore, the efficiency increased by factor 2.2 when the width was increased from 2:5nmto 7:5nm. These results indicate that thermionic emission is the most important process reducing efficiencyat temperatures in excess of 100 K. Moreover, the weak dependence of the rate of radiative recombinationon well width means that increasing well thickness is an effective way of suppressing thermionic emissionand thereby increasing efficiency in zincblende InGaN/GaN quantum wells, in contrast to those grown in thewurtzite phase.

Although the solid-state lighting industry has achieved huge successes in both red and blue part of the visible spectrum during the last 40 years, light-emitting diodes (LEDs) that emit green light...

Zincblende GaN has the potential to bridge the “green gap” due to the absence of internal electric fields with respect to wurtzite GaN. However, at present, the quality of zincblende GaN light emitting diodes (LEDs) is not yet sufficient for useful efficient green devices. One of the major challenges is the poor spectral purity of the emitted light. A multimicroscopy approach, combining scanning electron microscopy-cathodoluminescence (SEM-CL), scanning transmission electron microscopy (STEM), and scanning electron diffraction (SED), is applied on a single feature to enable cross correlation between techniques and to investigate the possible causes for the broad optical emission of a zincblende GaN LED structure. This investigation demonstrates that SEM-CL on a site-specific TEM cross section prepared by focused ion beam (FIB) microscope can provide access to nanoscale light emission variations that can be directly related to structural differences seen in STEM. We demonstrate that the general large quantum well (QW) emission peak width relates to quantum well thickness and In content fluctuations. Multiple low-energy QW emission peaks are found to be linked with stacking fault bunches that intersect the QWs. Splitting of the QW emission peak is also found to be caused by the formation of wurtzite-phase inclusions associated with twins formed within the zincblende matrix. Our characterization also illustrates the quantum well structure within such wurtzite inclusions and their impact on the optical emission.

We explore the production of single-walled carbon nanotubes (CNTs) in a stream surrounded by rich premixed laminar H 2 /air flames using a feedstock containing ethanol and ferrocene. The as-produced nanomaterials were characterised by Raman spectroscopy, transmission electron microscopy, scanning electron microscopy and X-ray diffraction. A formation window of equivalence ratios of 1.00–1.20 was identified, and single-walled CNT bundles with individual CNTs of an average diameter of 1 nm were observed. The formation of CNTs was accompanied by the production of highly crystalline Fe 3 O 4 nanoparticles of a size of 20–100 nm. The investigation of the limiting factors for the CNT synthesis was carried out systematically, assisted by numerical modelling. We conclude that the key factors affecting CNT synthesis are the surrounding flame temperatures, and the concentration of carbon available for CNT nucleation.

Current cubic zincblende III-Nitride epilayers grown on 3C-SiC/Si(001) substrates by metal-organic vapor-phase epitaxy contain a high density of stacking faults lying on the {111} planes. A combination of high-resolution scanning transmission electron microscopy and energy dispersive x-ray spectrometry is used to investigate the effects of alloy segregation around stacking faults in a zincblende III-nitride light-emitting structure, incorporating InGaN quantum wells and an AlGaN electron blocking layer. It is found that in the vicinity of the stacking faults, the indium and aluminum contents were a factor of 2.3 ± 1.3 and 1.9 ± 0.5 higher, respectively, than that in the surrounding material. Indium and aluminum are also observed to segregate differently in relation to stacking faults with indium segregating adjacent to the stacking fault while aluminum segregates directly on the stacking fault.

Zincblende InGaN/GaN quantum wells offer a potential improvement to the efficiency of green light emission by removing the strong electric fields present in similar structures. However, a high density of stacking faults may have an impact on the recombination in these systems. In this work, scanning transmission electron microscopy and energy-dispersive x-ray measurements demonstrate that one-dimensional nanostructures form due to indium segregation adjacent to stacking faults. In photoluminescence experiments, these structures emit visible light, which is optically polarized up to 86% at 10 K and up to 75% at room temperature. The emission redshifts and broadens as the well width increases from 2 nm to 8 nm. Photoluminescence excitation measurements indicate that carriers are captured by these structures from the rest of the quantum wells and recombine to emit light polarized along the length of these nanostructures.