Unusual Triple-State Switching of Thermally Induced Birefringence in a Two-Dimensional Perovskite Ferroelectric.

Birefringent crystals hold a significant position in optical and optoelectronic fields due to their capability to control polarized light. Despite various chemical strategies devoted to designing birefringent crystals, it remains a challenge to switch and manipulate birefringence under physical stimuli. Here we present an unusual triple-state switching of birefringence in a 2D perovskite ferroelectric, (N-methylcyclohexylammonium)2PbCl4 (1), which exhibits two reversible phase transitions at 361 and 373 K. The in-plane birefringence of 1 (Δnbc) shows three distinctive states inside the bc plane, namely, the low-, high-, and zero-Δnbc states. Strikingly, a huge augmentation of Δnbc is solidly confirmed up to ∼400% between its low and high states, far beyond other birefringent materials. The origin of this triple-state switching of birefringence involves the variation of the ferroelastic strain and domain in the vicinity of the phase transition. As an entirely new mode of switching birefringence, this work facilitates the further development of new intelligent nonlinear optics.

Field-Induced Antiferroelectric-Ferroelectric Transformation in Organometallic Perovskite Displaying Giant Negative Electrocaloric Effect.

Antiferroelectric materials with an electrocaloric effect (ECE) have been developed as promising candidates for solid-state refrigeration. Despite the great advances in positive ECE, reports on negative ECE remain quite scarce because of its elusive physical mechanism. Here, a giant negative ECE (maximum ΔS ∼ -33.3 J kg-1 K-1 with ΔT ∼ -11.7 K) is demonstrated near room temperature in organometallic perovskite, iBA2EA2Pb3I10 (1, where iBA = isobutylammonium and EA = ethylammonium), which is comparable to the greatest ECE effects reported so far. Moreover, the ECE efficiency ΔS/ΔE (∼1.85 J cm kg-1 K-1 kV-1) and ΔT/ΔE (∼0.65 K cm kV-1) are almost 2 orders of magnitude higher than those of classical inorganic ceramic ferroelectrics and organic polymers, such as BaTiO3, SrBi2Ta2O9, Hf1/2Zr1/2O2, and P(VDF-TrFE). As far as we know, this is the first report on negative ECE in organometallic hybrid perovskite ferroelectric. Our experimental measurement combined with the first-principles calculations reveals that electric field-induced antipolar to polar structural transformation results in a large change in dipolar ordering (from 6.5 to 45 µC/cm2 under the ΔE of 18 kV/cm) that is closely related to the entropy change, which plays a key role in generating such giant negative ECE. This discovery of field-induced negative ECE is unprecedented in organometallic perovskite, which sheds light on the exploration of next-generation refrigeration devices with high cooling efficiency.

A co-located QTL for seven spike architecture-related traits shows promising breeding use potential in common wheat (Triticum aestivum L.).

KEY MESSAGE: A co-located novel QTL for TFS, FPs, FMs, FFS, FFPs, KWS, and KWPs with potential of improving wheat yield was identified and validated. Spike-related traits, including fertile florets per spike (FFS), kernel weight per spike (KWS), total florets per spike (TFS), florets per spikelet (FPs), florets in the middle spikelet (FMs), fertile florets per spikelet (FFPs), and kernel weight per spikelet (KWPs), are key traits in improving wheat yield. In the present study, quantitative trait loci (QTL) for these traits evaluated under various environments were detected in a recombinant inbred line population (msf/Chuannong 16) mainly genotyped using the 16 K SNP array. Ultimately, we identified 60 QTL, but only QFFS.sau-MC-1A for FFS was a major and stably expressed QTL. It was located on chromosome arm 1AS, where loci for TFS, FPs, FMs, FFS, FFPs, KWS, and KWPs were also simultaneously co-mapped. The effect of QFFS.sau-MC-1A was further validated in three independent segregating populations using a Kompetitive Allele-Specific PCR marker. For the co-located QTL, QFFS.sau-MC-1A, the presence of a positive allele from msf was associate with increases for all traits: + 12.29% TFS, + 10.15% FPs, + 13.97% FMs, + 17.12% FFS, + 14.75% FFPs, + 22.17% KWS, and + 19.42% KWPs. Furthermore, pleiotropy analysis showed that the positive allele at QFFS.sau-MC-1A simultaneously increased the spike length, spikelet number per spike, and thousand-kernel weight. QFFS.sau-MC-1A represents a novel QTL for marker-assisted selection with the potential for improving wheat yield. Four genes, TraesCS1A03G0012700, TraesCS1A03G0015700, TraesCS1A03G0016000, and TraesCS1A03G0016300, which may affect spike development, were predicted in the physical interval harboring QFFS.sau-MC-1A. Our results will help in further fine mapping QFFS.sau-MC-1A and be useful for improving wheat yield.

Association of cord blood Ang-1 and sCD105 levels with bronchopulmonary dysplasia in preterm infants.

BACKGROUND: To investigate the relationship between cord blood levels of Angiopoietin-1 (Ang-1) and S-endoglin (sCD105) and bronchopulmonary dysplasia (BPD) in preterm infants. METHODS: Sixty-one preterm infants admitted to the neonatal intensive care unit of the study hospital between July 2021 and September 2022 were included. Cord blood was collected after the birth of premature infants. Ang-1 and sCD105 levels were quantified using the vascular endothelial growth factor enzyme-linked immunosorbent assay. Preterm infants were divided into BPD and non-BPD groups, and differences in Ang-1 and sCD105 levels between the two groups were compared. A binary logistic model was used to assess the association between low and high levels Ang-1 and BPD in preterm infants. RESULTS: In the study, there were 20 preterm infants with BPD (32.8%) and 41 preterm infants with non-BPD (67.2%). Ang-1 concentration levels were lower in the BPD group than in the non-BPD group (7105.43 (5617.01-8523.00) pg/ml vs. 10488.03 (7946.19-15962.77) pg/ml, P = 0.027). However, the sCD105 concentration levels were not significantly different between the BPD and non-BPD groups (P = 0.246). A median Ang-1 concentration of 8800.40 pg/ml was calculated. Logistic regression analysis showed that after adjusting for gestational age, birth weight, and maternal prenatal steroid hormone application, the odds ratio (OR) was 8.577 for the risk of BPD in preterm infants with Ang-1 concentrations of ≤ 8800.40 pg/ml compared to those with Ang-1 concentrations of > 8800.40 pg/ml (OR: 8.577, 95% confidence interval: 1.265-58.155, P = 0.028). CONCLUSION: Our study indicated that Ang-1 levels in the cord blood of preterm infants may be associated the risk of BPD. In the future, we will continue to conduct study with large samples.

Diagnostic Value of Transabdominal Ultrasonography in Gastrointestinal Malignant Tumors.

Objective: To explore the application value of transabdominal ultrasonography in the diagnosis of gastrointestinal malignant tumors. Methods: This study retrospectively analyzed the transabdominal ultrasound imaging data of 284 patients with gastrointestinal tumors admitted to our hospital from April 2019 to March 2022 and assessed the accuracy of transabdominal ultrasound in diagnosing different types of gastrointestinal tumor diseases. The diagnostic accuracy of transabdominal ultrasonography for TNM staging of gastrointestinal malignancies was calculated. Results: The sensitivity and specificity of transabdominal ultrasonography in the diagnosis of gastric cancer were (82.40% and 83.72%, respectively), colon cancer (77.78% and 88.35%, respectively), gastric stromal tumor (95.45% and 93.65%, respectively), gastric lymphoma (72.22% and 94.66%, respectively), colorectal lymphoma (80.00% and 95.42%, respectively), gastric mucosal hypertrophy (85.71% and 96.69%, respectively), and pyloric hypertrophy (92.59% and 97.79%, respectively). Among the 284 patients included, 152 patients had malignant tumors, including 34 patients with stage I, 30 patients with stage II, 51 patients with stage III, and 37 patients with stage IV. The accuracy of transabdominal ultrasonography for TNM staging of gastrointestinal malignancies was 85.53% (130/152). Conclusion: Transabdominal ultrasonography shows promise as a diagnostic tool for gastrointestinal malignant tumors; however, it is recommended to be used in conjunction with other detection methods such as fibrous gastrointestinal tract examination to minimize the risk of missed diagnoses and misdiagnoses. The study highlights the potential of transabdominal ultrasonography as a non-invasive and accessible diagnostic method for gastrointestinal malignancies. Further research and advancements in imaging technologies are crucial for enhancing diagnostic capabilities and improving patient outcomes in the future.

Zipper-Like Dynamic Switching of Coordination Bonds Gives a Polar Bimetallic Halide toward Self-Driven X-ray Detection.

Polar molecular crystals hold a promise for controlling bulk physical properties originated in their unique switchable polarity via structural transformation. However, the mechanisms for switching polarization are mainly limited to displacive and disorder-order phase transitions, which rarely involve the reconstruction of chemical bonds. Here, we have switched and tuned electric polarization in a bimetallic halide, (Neopentylammonium)4AgBiBr8 (1), as verified by light-excited pyroelectric effect. Most notably, its Ag-Br coordination bonds show a zipper-like dynamic switching behavior from the 'locked' to 'unlocked' state, namely, reconstruction of chemical bonds. Coupling with the dynamic ordering of organic cations, this bond-switching transition makes a contribution to switchable polarization of 1. As expected, its polarity creates pyroelectric effect for self-driven X-ray detection with high sensitivity (3.8×103 µC Gy-1 cm-2) and low limit of detection (4.8 nGy s-1). This work on the bond-switching mechanism provides an avenue to design polar molecular candidate for smart optoelectronic devices.

Visible-Photo-Assisted Phase Switching of Antiferroelectric-to-Ferroelectric Orders in an I3 --Intercalated 2D Perovskite.

Antiferroelectric (AFE) has emerged as a promising branch of electroactive materials, due to intriguing physical attributes stemming from the electric field-induced antipolar-to-polar phase transformation. However, the requirement of extremely high electric field strength to switch adjacent sublattice polarization poses great challenges for exploiting new molecular AFE system. Although photoirradiation is striking as a noncontact and nondestructive manipulation tool to optimize physical properties, optical control of antiferroelectricity still remains unexplored. Here, by adopting light-sensitive I3 - anion into 2D perovskite family, we design a new I3 --intercalated molecular AFE of (t-ACH)2EA2Pb3I10(I3)0.5 ⋅ ((H3O)(H2O))0.5 (1, t-ACH=trans-4-aminomethyl-1-cyclohexanecarboxylate, EA=ethylammonium). The I3 --intercalating gives an ultra-narrow band gap of 1.65 eV with strong absorption. In term of AFE structure, the anti-parallel alignment of electric dipoles results in a large spontaneous polarization of 4.3 µC/cm2. Strikingly, 1 merely shows AFE behaviour in the dark even under ultrahigh voltage, while the field-induced ferroelectric state can be facilely obtained upon visible illumination. Such unprecedented visible-photo-assisted phase switching ascribes to the incorporation of photoactive I3 - anions that reduces AFE-to-ferroelectric switching barrier. This pioneering work on the photo-assisting transformation of ferroic orders paves a way to develop future photoactive materials with potential applications.

Acquiring Bulk Anomalous Photovoltaic Effect in Single Crystals of a Lead-Free Double Perovskite with Aromatic and Alkali Mixed-Cations.

The bulk anomalous photovoltaic (BAPV) effect of acentric materials refers to a distinct concept from traditional semiconductor-based devices, of which the above-bandgap photovoltage hints at a promise for solar-energy conversion. However, it is still a challenge to exploit new BAPV-active systems due to the lacking of knowledge on the structural origin of this concept. BAPV effects in single crystals of a 2D lead-free double perovskite, (BBA)2 CsAgBiBr7 (1, BBA = 4-bromobenzylammonium), tailored by mixing aromatic and alkali cations in the confined architecture to form electric polarization are acquired here. Strikingly, BAPV effects manifested by above-bandgap photovoltage (VOC ) show unique attributes of directional anisotropy and positive dependence on electrode spacing. The driving source stems from orientations of the polar aromatic spacer and Cs+ ion drift, being different from the known built-in asymmetry photovoltaic heterojunctions. As the first demonstration of the BAPV effect in the double perovskites, the results will enrich the family of environmentally green BAPV-active candidates and further facilitate their new optoelectronic application.

Polarization-Dependent Large Photorefractive Effect In A Wide Bandgap 2D Metal Halide Ferroelectric.

Photorefractive effect of ferroelectrics refers to the light-induced change of refractive index, which is an optical controlling avenue in holographic storage and image processing. For most ferroelectrics, however, the small photorefractive effect (10-5 -10-4 ) hinders their practical application and it is urgent to exploit new photorefractive system. Here, for the first time, strong photorefractive effects are achieved in a 2D metal-halide ferroelectric, [CH3 (CH2 )3 NH3 ]2 (CH3 NH3 )Pb2 Cl7 (1), showing large spontaneous polarization (≈4.1 µC cm-2 ) and wide optical bandgap (≈3.20 eV). Notably, under light irradiation, 1 enables a large variation of refractive indices up to ≈ 1× 10-3 , being one order higher than the existing materials and comparable to the state-of-the-art inorganic ferroelectrics. This intriguing photorefractive behavior involves with the sharp variation of polarization caused by photo-pyroelectricity. As the first report of 2D metal-halide photorefractive ferroelectric, this work sheds light on optical controlling of physical properties in electric-ordered materials.

Polarization-Sensitive Detector of Two-Dimensional Multilayer Hybrid Perovskite Crystals Showing High Polarization Ratio to Weak Light.

Two-dimensional (2D) hybrid perovskite materials have been widely used for polarization-sensitive photodetection due to their fascinating optical and physical attributes. However, studies on those materials that enable strong polarized-light activities under a weak-light condition remain quite scarce. Here, by tailoring aromatic cation into 3D prototype, we have successfully obtained a new 2D hybrid perovskite, (FPEA)2 (MA)Pb2 Br7 (1, where FPEA is 4-fluorophenethylammonium and MA is methylammonium). The alternative alignment of inorganic and organic structural components results in significant anisotropy, including optical absorption and electric conductivity. The coupling effect of these anisotropic properties in 1 gives rise to strong dichroic activities toward detecting polarized light. Especially, under weak light intensity (∼330 nW/cm2 ), it can still generate a large polarization ratio up to 1.35, which is even higher than those of some typical 2D materials (i. e., GeSe ∼1.09). Besides, single crystal-based photodetector of 1 displays fascinating detecting performances, including large photocurrent on/off ratio (∼104 ), fast response time (∼154/182 µs) and excellent antifatigued stability. These findings disclose the potentials of 1 as a robust candidate for detecting weak polarized light, which has practical applications in the field of polarized optoelectronics.

A promising QTL QSns.sau-MC-3D.1 likely superior to WAPO1 for the number of spikelets per spike of wheat shows no adverse effects on yield-related traits.

KEY MESSAGE: A likely new locus QSns.sau-MC-3D.1 associated with SNS showing no negative effect on yield-related traits compared to WAPO1 was identified and validated in various genetic populations under multiple environments. The number of spikelets per spike (SNS) is one of the crucial factors determining wheat yield. Thus, improving our understanding of the genes that regulate SNS could help develop wheat varieties with higher yield. In this study, a recombinant inbred line (RIL) population (MC) containing 198 lines derived from a cross between msf and Chuannong 16 (CN16) was used to construct a genetic linkage map using the GenoBaits Wheat 16 K Panel. The genetic map contained 5,991 polymorphic SNP markers spanning 2,813.25 cM. A total of twelve QTL for SNS were detected, and two of them, i.e., QSns.sau-MC-3D.1 and QSns.sau-MC-7A, were stably expressed. QSns.sau-MC-3D.1 had high LOD values ranging from 4.99 to 11.06 and explained 9.71-16.75% of the phenotypic variation. Comparison of QSns.sau-MC-3D.1 with previously reported SNS QTL suggested that it is likely a novel one, and two kompetitive allele-specific PCR (KASP) markers were further developed. The positive effect of QSns.sau-MC-3D.1 was also validated in three biparental populations and a diverse panel containing 388 Chinese wheat accessions. Genetic analysis indicated that WHEAT ORTHOLOG OFAPO1 (WAPO1) was a candidate gene for QSns.sau-MC-7A. Pyramiding of QSns.sau-MC-3D.1 and WAP01 had a great additive effect increasing SNS by 7.10%. Correlation analysis suggested that QSns.sau-MC-3D.1 was likely independent of effective tiller number, plant height, spike length, anthesis date, and thousand kernel weight. However, the H2 haplotype of WAPO1 may affect effective tiller number and plant height. These results indicated that utilization of QSns.sau-MC-3D.1 should be given priority for wheat breeding. Geographical distribution analysis showed that the positive allele of QSns.nsau-MC-3D.1 was dominant in most wheat-producing regions of China, and it has been positively selected among modern cultivars released in China since the 1940s. Gene prediction, qRT-PCR analysis, and sequence alignment suggested that TraesCS3D03G0216800 may be the candidate gene of QSns.nsau-MC-3D.1. Taken together, these results enrich our understanding of the genetic basis of wheat SNS and will be useful for fine mapping and cloning of the gene underlying QSns.sau-MC-3D.1.

Building Block-Inspired Hybrid Perovskite Derivatives for Ferroelectric Channel Layers with Gate-Tunable Memory Behavior.

Ferroelectric photovoltaics driven by spontaneous polarization (Ps ) holds a promise for creating the next-generation optoelectronics, spintronics and non-volatile memories. However, photoactive ferroelectrics are quite scarce in single homogeneous phase, owing to the severe Ps fatigue caused by leakage current of photoexcited carriers. Here, through combining inorganic and organic components as building blocks, we constructed a series of ferroelectric semiconductors of 2D hybrid perovskites, (HA)2 (MA)n-1 Pbn Br3n+1 (n=1-5; HA=hexylamine and MA=methylamine). It is intriguing that their Curie temperatures are greatly enhanced by reducing the thickness of inorganic frameworks from MAPbBr3 (n=∞, Tc =239 K) to n=2 (Tc =310 K, ΔT=71 K). Especially, on account of the coupling of room-temperature ferroelectricity (Ps ≈1.5 µC/cm2 ) and photoconductivity, n=3 crystal wafer was integrated as channel field effect transistor that shows excellent a large short-circuit photocurrent ≈19.74 µA/cm2 . Such giant photocurrents can be modulated through manipulating gate voltage in a wide range (±60 V), exhibiting gate-tunable memory behaviors of three current states ("-1/0/1" states). We believe that this work sheds light on further exploration of ferroelectric materials toward new non-volatile memory devices.

Soft Multiaxial Molecular Ferroelectric Thin Films with Self-Powered Broadband Photodetection.

Molecular ferroelectric films (MFFs) offer a good platform for miniaturized electronic devices, which are inseparable from their multiaxial nature. Despite great studies, soft MFFs with broadband photo-electroactivity still remain a huge blank as the photoexcited leakage current will severely deteriorate ferroelectricity, hindering their optoelectronic applications. Here, we constructed the multiaxial MFF of HA2EA2Pb3I10 (1, where EA = ethylammonium and HA = n-hexylammonium) in 2D multilayered perovskites. Eight equivalent polarization directions were observed in 1, as verified by its symmetry breaking (i.e., 4/mmmFm species), which is the maximum among 2D multilayered perovskites and even more than that of classic ceramic BaTiO3. Specially, spin-coated flexible MFFs of 1 are approximately orientated parallel to layered perovskite frameworks, exhibiting in-plane spontaneous polarization (Ps = 1.8 µC/cm2) and broadband absorption (∼1.83 eV). In addition, self-powered broadband detection (∼0.55 µA/cm2 at 637 nm illumination) was achieved on the soft films, revealing their potential for flexible and wearable electronic devices. Our result sheds light on the design of flexible photoelectronic devices and provides an effective way to expand the applications of 2D molecular ferroelectric materials.

Hybrid integrated ultralow-linewidth and fast-chirped laser for FMCW LiDAR.

Narrow linewidth and fast-chirped frequency are essential in frequency-modulated continuous-wave lasers. We introduce a laser that meets these requirements by coupling a distributed feedback laser with an external high-Q microring resonator, where a bulky stacked piezoelectric chip is attached to the resonator for fast tuning. The laser demonstrates an ultranarrow intrinsic linewidth of 22 Hz in the self-injection-locked state. Actuated by the bulky piezoelectric chip, the maximum triangular actuation bandwidth can reach 100 kHz. The driving voltage is filtered to avoid a resonant mechanical mode, obtaining the minimum residual linearity error at 10 kHz with a 4.2 GHz tuning range. A light detection and ranging system was set up for a proof-of-concept experiment, demonstrating a high detection precision with standard deviations of 2.7 and 4.0 cm for targets at 15 and 30 m, respectively.

Transmission in home environment associated with the second wave of COVID-19 pandemic in India.

India has suffered from the second wave of COVID-19 pandemic since March 2021. This wave of the outbreak has been more serious than the first wave pandemic in 2020, which suggests that some new transmission characteristics may exist. COVID-19 is transmitted through droplets, aerosols, and contact with infected surfaces. Air pollutants are also considered to be associated with COVID-19 transmission. However, the roles of indoor transmission in the COVID-19 pandemic and the effects of these factors in indoor environments are still poorly understood. Our study focused on reveal the role of indoor transmission in the second wave of COVID-19 pandemic in India. Our results indicated that human mobility in the home environment had the highest relative influence on COVID-19 daily growth rate in the country. The COVID-19 daily growth rate was significantly positively correlated with the residential percent rate in most state-level areas in India. A significant positive nonlinear relationship was found when the residential percent ratio ranged from 100 to 120%. Further, epidemic dynamics modelling indicated that a higher proportion of indoor transmission in the home environment was able to intensify the severity of the second wave of COVID-19 pandemic in India. Our findings suggested that more attention should be paid to the indoor transmission in home environment. The public health strategies to reduce indoor transmission such as ventilation and centralized isolation will be beneficial to the prevention and control of COVID-19.

Broadband Photoresponses from Ultraviolet to Near-Infrared (II) Region through Light-induced Pyroelectric Effects in a Hybrid Perovskite.

Broadband photodetection has shown a great promise for diverse applications, while the realization of plateau photoresponse from ultraviolet (UV) to near-infrared (NIR) spectral region is very challenging. Herein, we exploit photoexcited pyroelectric effect in a chiral hybrid perovskite, (N, N-dimethylcyclohexylammonium)PbBr3 (1), serving as a new pathway to drive broadband photoactivities. It is a room-temperature pyroelectric with large polarization of ≈6.4 µC cm-2 and high pyroelectric figure-of-merits (FV =1.0×10-2  cm2 µC-1 and FD =7.1×10-5  Pa-1/2 ). Strikingly, light-induced pyroelectric effect arising from spontaneous polarization is observed in 1, which cover UV (266 nm) to NIR-II (1950 nm) full spectral region. The broadband photoresponses actualized by pyroelectricity break the limit of optical band gap. As the first demonstration of photo-pyroelectricity covering UV-to-NIR spectral region in hybrid perovskites, this work paves a pathway to assemble high-performance smart devices.

Temperature-insensitive Mach-Zehnder interferometer based on a silicon nitride waveguide platform.

Wavelength shift, caused by temperature fluctuation, critically limits the application of photonic systems. Here, the waveguide geometry is optimized to minimize the wavelength shift due to temperature change and fabrication error. A temperature-insensitive Mach-Zehnder interferometer filter is proposed for a wavelength locker, based on a silicon nitride waveguide. The proposed device achieves a 0.6 pm/K spectral shift over the C-band, which meets the requirements of a wavelength locker for application in dense wavelength division multiplex systems.

Effects of long axis in-plane vs short axis out-of-plane techniques during ultrasound-guided vascular access.

BACKGROUND: Currently, whether long-axis in-plane (LA-IP) is superior to short-axis out-of-plane (SA-OOP) during ultrasound-guided vascular access remains inconclusive. We, therefore, conducted a meta-analysis of randomized controlled trials to compare the effects of LA-IP vs SA-OOP techniques in patients undergoing ultrasound-guided vascular access (USGVA). METHODS: A computer-based literature search of PubMed, Embase, and the Cochrane Library (up to October 2015) was performed to identify randomized controlled trials that evaluated the effects of LA-IP compared with SA-OOP in patients undergoing USGVA. The primary end point was the first-pass success rate. Secondary end points included mean time to success, mean attempts to success, and incidence of the complication of hematoma. Weighted mean differences (WMDs) and relative risks (RRs) with 95% confidence intervals (CIs) were calculated by random-effects model. RESULTS: Five eligible studies with a total of 470 patients satisfied the inclusion criteria. There was no significant difference for the first-pass success rate (RR, 1.06; 95% CI, 0.91-1.23; P = .44), mean time to success (WMD, 4.78seconds; 95% CI, -4.43 to 13.99; P = .31), mean attempts to success (WMD, 0.06 times; 95% CI, -0.23 to 0.35; P = .69), and incidence of the complication of hematoma (RR, 2.86; 95% CI, 0.32-25.42; P = .35) between the LA-IP and SA-OOP groups. CONCLUSIONS: There is insufficient evidence to definitively choose either LA-IP or SA-OOP in patients undergoing USGVA. Further robustly well-designed trials are warranted to investigate the appropriate technique in patients receiving USGVA.

Asymmetric hydrogenation of aromatic ketones by new recyclable ionic tagged ferrocene-ruthenium catalyst system.

Newly developed ferrocene-oxazoline-phosphine ligands containing quaternary ammonium ionic groups exhibited excellent catalytic performance for the ruthenium-catalyzed hydrogenation of aromatic ketonic substrates to give chiral secondary alcohols with high levels of conversions and enantioselectivities. Simple manipulation process, water tolerance, high activity and good recyclable property make this catalysis practical and appealing.

[Changes in T lymphocyte subsets in preterm infants with intrauterine growth retardation].

OBJECTIVE: To study changes in T lymphocyte subsets in preterm infants with intrauterine growth retardation (IUGR). METHODS: The study enrolled 29 IUGR preterm infants, 38 preterm infants born appropriate for gestational age (AGA), and 20 healthy full-term infants. Peripheral blood was sampled during the first 24 hours of life, and again at a corrected age of 38 weeks of the preterm infants. T lymphocyte subsets were analyzed by flow cytometry, and absolute counts of leukocytes, total lymphocytes, and T lymphocytes were determined with an automated hematology analyzer. RESULTS: Within the first 24 hours of life, percentages of CD3(+) and CD4(+) were lower in IUGR preterm infants than in AGA preterm infants and full-term infants (P<0.05), percentages of CD8(+) and CD4(+)/CD8(+) ratio were lower in IUGR preterm infants than in full-term infants (P<0.05), and percentages of CD3(+), CD4(+) and CD4(+)/CD8(+) ratio were lower in AGA preterm infants than in full-term infants (P<0.05). Moreover, the absolute counts of total lymphocytes were lower in IUGR preterm infants than in full-term infants (P<0.05); the absolute counts of T lymphocytes were lower in preterm infants, regardless of IUGR, than in full-term infants (P<0.05), and lower in IUGR infants than in AGA infants (P<0.05). At the corrected age of 38 weeks, percentages of CD3(+), CD4(+) and CD4(+)/CD8(+) ratio were increased in both IUGR and AGA infants as compared to the measurements within the first 24 hours of life (P<0.05), and percentages of CD3(+), CD4(+), CD8(+) and CD4(+)/CD8(+) ratio were lower in IUGR infants than in AGA infants (P<0.05), whereas there were no significant differences in counts of leukocytes, total lymphocytes and T lymphocytes between IUGR and AGA infants (P>0.05). CONCLUSIONS: There may be a certain degree of compromise in cell-mediated immunity in preterm infants with IUGR and this compromise may last to 38 weeks after birth.