Monolayer Nanosheets with an Extremely High Drug Loading toward Controlled Delivery and Cancer Theranostics

2D nanomaterials have attracted considerable research interest in drug delivery systems, owing to their intriguing quantum size and surface effect. Herein, Gd³⁺ -doped monolayered-double-hydroxide (MLDH) nanosheets are prepared via a facile bottom-up synthesis method, with a precisely controlled composition and uniform morphology. MLDH nanosheets as drug carrier are demonstrated in coloading of doxorubicin and indocyanine green (DOX&ICG), with an ultrahigh drug loading content (LC) of 797.36% and an encapsulation efficiency (EE) of 99.67%. This is, as far as it is known, the highest LC level at nearly 100% of EE among previously reported 2D drug delivery systems so far. Interestingly, the as-prepared DOX&ICG/MLDH composite material shows both pH-controlled and near-infrared-irradiation-induced DOX release, which holds a promise in stimulated drug release. An in vivo dual-mode imaging, including near-infrared fluorescence and magnetic resonance imaging, enables a noninvasive visualization of distribution profiles at the tumor site. In addition, in vitro and in vivo therapeutic evaluations demonstrate an excellent trimode synergetic anticancer activity and superior biocompatibility of DOX&ICG/MLDH. Therefore, MLDH nanosheets provide new perspectives in the design of multifunctional nanomedicine, which shows promising applications in controlled drug delivery and cancer theranostics.

Molecular influence of anterior cruciate ligament tear remnants on chondrocytes: a biologic connection between injury and osteoarthritis

OBJECTIVE

Anterior cruciate ligament (ACL) injury initiates a cascade of events often leading to osteoarthritis (OA). ACL reconstruction does not alter the course of OA, suggesting that heightened OA risk is likely due to factors in addition to the joint instability. We showed that torn ACL remnants express periostin (POSTN) in the acute phase of injury. Considering that ACL injury predisposes to OA and that POSTN is associated with cartilage metabolism, we hypothesize that ACL injury affects chondrocytes via POSTN.

DESIGN

Cartilage was obtained from osteoarthritic patients and ACL remnants were collected from patients undergoing ACL reconstruction. Crosstalk between ACL remnants and chondrocytes was studied in a transwell co-culture system. Expression of POSTN and other anabolic and catabolic genes was assessed via real-time polymerase chain reaction (PCR). Immunostaining for periostin was performed in human and mouse cartilage. The impact of exogenous periostin and siRNA-mediated ablation of periostin on matrix metabolism and cell migration was examined. Furthermore, the effect of anabolic (transforming growth factor beta 1 [TGF-β1]) and catabolic (interleukin 1 beta [IL-1β]) factors on POSTN expression was investigated.

RESULTS

ACL remnants induced expression of POSTN, MMP13 and ADAMTS4. Periostin levels were significantly higher in osteoarthritic compared to normal cartilage. Exogenous periostin induced MMP13 expression and cell migration, and repressed COL1A1 expression while POSTN knockdown inhibited expression of both anabolic and catabolic genes and impeded cell migration. TGF-β1 and IL-1β treatment did not alter POSTN expression but influenced chondrocyte metabolism as determined by quantification of anabolic and catabolic genes via real-time PCR.

CONCLUSIONS

ACL remnants can exert paracrine effects on cartilage, altering cellular homeostasis. Over time, this metabolic imbalance could contribute to OA development.

Spontaneous polarization switching and piezoelectric enhancement of PVDF through strong hydrogen bonds induced by layered double hydroxides

The spontaneous dipole alignment of PVDF has been achieved in the formation process of a film through strong hydrogen bonds between PVDF and layered double hydroxides (LDHs), and the as-prepared composite film exhibits excellent energy conversion and storage ability.

Changes in nitric oxide levels and their relationship with callose deposition during the interaction between soybean and Soybean mosaic virus

The present study aimed to investigate changes in nitric oxide (NO) level and its relationship with callose deposition during the interaction between soybean and Soybean mosaic virus (SMV). Soybean cv. 'Jidou 7' and SMV strains N3 and SC-8 were used to constitute incompatible and compatible combinations. Intracellular NO was labelled with the NO-specific fluorescence probe DAF-FM DA. Confocal laser scanning microscopy (CLSM) was then used to observe changes in NO production during SMV infection-induced defence responses in soybean. The results showed NO fluorescence increased rapidly at 2-72 h post-inoculation, peaked at 72 h and then decreased in the incompatible combination. However, in the compatible combination, extremely weak NO fluorescence appeared in the early stage (2-24 h) post-inoculation, but was not observed thereafter. Injections of the NO scavenger c-PTIO prior to inoculation postponed the onset of NO production to 48 or 72 h post-inoculation. The same occurred when injections of NR or NOS inhibitors were applied prior to inoculation. The observation of callose fluorescence in the incompatible combination revealed that either the elimination or reduction of NO in the early stage led to a delay in callose formation, enabling the virus to cause systemic infection. Together with our previous findings, this study indicates that viral infection could induce NO production and callose deposition during the incompatible interaction between soybean and SMV. The production of NO involves NR and NOS enzymatic pathways, and NO mediates the process of callose deposition at plasmodesmata.

Hydrotalcite monolayer toward high performance synergistic dual-modal imaging and cancer therapy

Recently, theranostic has drawn tremendous attention by virtue of the nanotechnology development and new material exploration. Herein, we reported a novel theranostic system by loading Au nanoclusters (AuNCs) and Chlorin e6 (photosensitizer, Ce6) onto the monolayer nanosheet surface of Gd-doped layered double hydroxide (Gd-LDH). The as-prepared Ce6&AuNCs/Gd-LDH exhibits a largely enhanced fluorescence quantum yield (QY) of 18.5% relative to pristine AuNCs (QY = 3.1%) as well as superior T₁ magnetic resonance imaging (MRI) performance (r₁ = 17.57 mM^-1s^-1) compared with commercial MRI contrast agent (Gd(III)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (Gd-DOTA): r₁ ≈ 3.4 mM^-1s^-1), resulting from a synergistic effect between AuNCs and Gd-LDH. In addition, both in vitro and in vivo therapeutic evaluations demonstrate an efficient dual-modality imaging guided anticancer performance, especially the synergetic enhanced magnetic resonance/fluorescence (MR/FL) visualization of tumor site. Therefore, this work demonstrates a successful paradigm for the design and preparation of LDHs monolayer-based theranostic material, which holds great promises in practical applications.

[Epidemiological characteristics of newly reported HIV infections in Chinese and Burmese residents, during 2012-2016 in Dehong Dai and Jingpo Autonomous Prefecture, Yunnan province]

Objective: To understand the epidemiological characteristics of newly reported HIV infections in Chinese and Burmese residents during 2012-2016 in Dehong Dai and Jingpo Autonomous Prefecture of Yunnan province (Dehong) and to provide evidence for the development of related programs on prevention and control. Methods: All the HIV infections who were newly reported during 2012-2016 in Dehong, were recruited as the study subjects, with epidemiological characteristics of the cases analyzed by using the software SPSS 22.0. Results: A total of 5 692 HIV infections were newly reported between 2012 and 2016 (including 5 592 in this study), in which the Chinese patients accounted for 43.3% (2 419) and the rest 56.7% (3 173) were Burmese. Differences in age, gender and other social characteristics of these newly reported HIV infections were statistically significant between the Chinese and the Burmese (all p-values <0.05). Most cases were males and between the age of 20-49 years old. Other characteristics of the patients would include: having had primary school education, married, being farmers, and with CD(4)(+)T cells counts ≥350 cells/μl. HIV infection was mainly transmitted through sexual contact among the Chinese patients but through injecting drug use among the Burmese patients. Conclusions: Epidemiological characteristics of the newly reported HIV infections were different between the Chinese and the Burmese, between 2012 and 2016 in Dehong. Targeted prevention and control programs should be taken.

Confined Synthesis of Carbon Nitride in a Layered Host Matrix with Unprecedented Solid-State Quantum Yield and Stability

Fluorescent carbon nanomaterials have drawn tremendous attention for their intriguing optical performances, but their employment in solid-state luminescent devices is rather limited as a result of aggregation-induced photoluminescence quenching. Herein, ultrathin carbon nitride (CN) is synthesized within the 2D confined region of layered double hydroxide (LDH) via triggering the interlayer condensation reaction of citric acid and urea. The resulting CN/LDH phosphor emits strong cyan light under UV-light irradiation with an absolute solid-state quantum yield (SSQY) of 95.9 ± 2.2%, which is, to the best of our knowledge, the highest value of carbon-based fluorescent materials ever reported. Furthermore, it exhibits a strong luminescence stability toward temperature, environmental pH, and photocorrosion. Both experimental studies and theoretical calculations reveal that the host-guest interactions between the rigid LDH matrix and interlayer carbon nitride give the predominant contribution to the unprecedented SSQY and stability. In addition, prospective applications of the CN/LDH material are demonstrated in both white light-emitting diodes and upconversion fluorescence imaging of cancer cells.

Effect of convection and B1 inhomogeneity on singlet relaxation experiments

Nuclear spin singlet lifetimes can often exceed the T₁ length scales by a large factor. This property makes them suitable for polarization storage. The measurement of such long lifetimes itself can become challenging due to the influence of even very weak relaxation mechanisms. Here we show that a judicious choice of the singlet-to-triplet conversion method is highly important in order to achieve reliable singlet relaxation measurements. In particular, we identify thermal convection, in connection with B₁ field gradients, asa significant apparent decay mechanism, which limits the ability to measure the true singlet state lifetimes. Highly B₁-compensated broadband singlet excitation/detection sequences are shown to minimize the influence of macroscopic molecular motion and B₁ inhomogeneity.

Hydroxyl-triggered fluorescence for location of inorganic materials in polymer-matrix composites

We present a locating technique for inorganic materials in polymer-matrix composites through a post-labeling approach based on specific covalent binding.

There is a long-standing challenge to realize in situ visualization of incorporated inorganic materials in organic–inorganic composites in a post-labeling manner, owing to the lack of specific fluorescent organic dye molecules for targeting inorganic materials. Herein, we observe that the specific covalent B–O binding between the hydroxyl groups of inorganic materials and commercially available aggregation-induced emission (AIE)-active boronic acid could lead to the formation of highly emissive solid-state fluorescent composite materials. The hydroxyl-triggered luminescent probe may serve as a practical method for in situ location of incorporated inorganic materials in polymer-matrix composites by simply dipping the composite film in boronic acid-modified AIE solution. This present work offers a non-invasive avenue to locate inorganic materials which possess hydroxyl-groups in polymer-matrix composites, thereby developing a convenient screening strategy for assessing the advanced properties of composites. This strategy can also be extended to the targeted tracing of other inorganic materials with inherent and functionalized carboxyl, amino, sulfhydryl and other groups via tuning the binding affinity between the inorganic materials and luminescent molecules.

Comprehensive analysis of proton range uncertainties related to stopping-power-ratio estimation using dual-energy CT imaging

The dual-energy CT-based (DECT) approach holds promise in reducing the overall uncertainty in proton stopping-power-ratio (SPR) estimation as compared to the conventional stoichiometric calibration approach. The objective of this study was to analyze the factors contributing to uncertainty in SPR estimation using the DECT-based approach and to derive a comprehensive estimate of the range uncertainty associated with SPR estimation in treatment planning. Two state-of-the-art DECT-based methods were selected and implemented on a Siemens SOMATOM Force DECT scanner. The uncertainties were first divided into five independent categories. The uncertainty associated with each category was estimated for lung, soft and bone tissues separately. A single composite uncertainty estimate was eventually determined for three tumor sites (lung, prostate and head-and-neck) by weighting the relative proportion of each tissue group for that specific site. The uncertainties associated with the two selected DECT methods were found to be similar, therefore the following results applied to both methods. The overall uncertainty (1σ) in SPR estimation with the DECT-based approach was estimated to be 3.8%, 1.2% and 2.0% for lung, soft and bone tissues, respectively. The dominant factor contributing to uncertainty in the DECT approach was the imaging uncertainties, followed by the DECT modeling uncertainties. Our study showed that the DECT approach can reduce the overall range uncertainty to approximately 2.2% (2σ) in clinical scenarios, in contrast to the previously reported 1%.

[Therapeutic effect of a new hybrid technique which combined laparoscopic method and abdominal repair for parastomal hernia repair]

Objective: To investigate the safety and effectiveness of a new hybrid technique which combined laparoscopic method and abdominal repair (Dual Lap) for parastomal herniarepair. Methods: The clinical and follow-up data of 27 cases who accepted Dual Lap procedure performed at Department of Hernia and Abdominal Wall Surgery, Wuhan Central Hospital, Tongji Medical College of Huazhong University from January 2010 to January 2015 were analyzed retrospectively. The data included 22 male patients and 5 female patients with mean age of 54 years. Of the patients, there were 19 cases of the left hernia and 8 cases of the right hernia, without ostomy hernia repair history. There were 4 cases of the occult hernial defects during the operation. There were 8 patients with ilealneobladder, 2 patients with ileostomyafter total colectomy for familial adenomatous polyposis, 3 patients with ileostomy and 14 patients with colostomy for ulcerative colitis. Results: All cases underwent hybrid technique successfully. The mean operation time was (108±16) minutes(ranging from 90 to 150 minutes) and the diameter of the hernial ring was (6.4±1.8)cm (ranging from 3 to 13 cm). There were no intestinal, kidney and ureteral obstructions in operations. Five cases need to use the analgesic adjuvant at 48-hour after operation. The time of postoperative defecations was (9.3±2.4) days (ranging from 7 to 16 days) and there were no intestinal leakage, local hematoma, wound infection and fat liquefaction after operations. All patients were followed up for (16.3±4.2) months (ranging from 12 to 48 months). There was no ileus, obvious seroma, hernia recurrence, chronic pain and mesh infection. Conclusion: The Dual Lap procedureis safe and effective for parastomal hernia repair with less complication.

Hierarchical CoNi-Sulfide Nanosheet Arrays Derived from Layered Double Hydroxides toward Efficient Hydrazine Electrooxidation

A hierarchical CoNi-sulfide nanosheet array is fabricated via an in situ reduction of CoNi-layered double hydroxide (LDH) nanosheets, then a vulcanization process. The material inherits the morphology of the LDH precursor, consisting of well-distributed CoNi-alloy@CoNi-sulfide nanoparticles with a core-shell structure, and demonstrates promising performance toward hydrazine electrooxidation.

A meta-analysis of breastfeeding and osteoporotic fracture risk in the females

Our meta-analysis included 12 studies from PubMed, Embase, and Web of Science. Finding indicated breastfeeding may well reduce the risk of osteoporotic fracture.

INTRODUCTION

Several epidemiologic studies have investigated that breastfeeding is associated with short-term bone loss in the women, but the long-term effect on osteoporotic fracture risk remains unclear. Thus, we conducted this meta-analysis to explore the potential association between breastfeeding and osteoporotic fracture risk in the females and possible dose-response relationship between them.

METHODS

We searched PubMed, Embase, and Web of Science (ISI) up to April 2016 for relevant articles associated between breastfeeding and osteoporotic fracture. Pooled relative risks (RRs) with 95 % confidence intervals (CIs) were calculated with a random-effects model. Dose-response analysis was performed by restricted cubic spline.

RESULTS

Twelve articles including 14,954 participants were identified. The pooled RRs of osteoporotic hip and forearm fracture for the highest vs lowest duration of breastfeeding were 0.84 (95 % CI 0.67-1.05), 0.72 (95 % CI 0.52-0.99), and 0.82 (95 % CI 0.56-1.19), respectively. In subgroup analysis, breastfeeding was associated with a decreased risk of osteoporotic fracture in case-control study (RR = 0.70, 95 % CI 0.49-0.99) and postmenopausal women (RR = 0.66, 95 % CI 0.47-0.93). In dose-response analysis, osteoporotic and hip fracture risk decreased by 0.9 and 1.2 % for each month increment of breastfeeding, respectively.

CONCLUSIONS

Our meta-analysis revealed that breastfeeding may well reduce the risk of osteoporotic fracture. More cohort studies with large sample sizes are needed to confirm the conclusion.

Two-dimensional confined electron donor–acceptor co-intercalated inorganic/organic nanocomposites: an effective photocatalyst for dye degradation

An effective photocatalyst for dye degradation based on two-dimensional confined electron donor–acceptor co-assembled layered double hydroxide nanocomposites was developed.

Novel Visible-Light Photodetector Based on Two-Dimensional Confined Electron Donor-Acceptor Co-Assembled Layered Double Hydroxide Ultrathin Films

Photodetectors are a class of critical optoelectronic devices that can transform incident light into a detectable electrical signal. In this work, we develop a novel photodetector based on two-dimensional (2D) confined electron donor-acceptor co-assembled ultrathin films (UTFs). The (PCDTBT@CN-PPV/LDHs) _n UTFs are composed of an organic electron donor, poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] (PCDTBT), and an acceptor, poly(5-(2-ethylhexyloxy)-2-methoxy-cyanoterephthalylidene) (CN-PPV), within inorganic Mg₂Al-layered double hydroxides (LDHs). The UTFs exhibit broad-range visible-light absorption, from 400 to 650 nm, resulting from complementary absorption of PCDTBT and CN-PPV. The fluorescence emission of the UTFs is completely quenched, implying the occurrence of photoinduced charge transfer (PCT). As a novel photodetector, the co-assembled UTFs have a high photocurrent and on/off switching ratio (300 nA/∼120), in contrast to those of the PCDTBT/CN-PPV drop-casting thin film (5.4 nA/∼1.6); a fast response; a short recovery time (lower than 0.1 s); and excellent wavelength and light-intensity dependence. The PCT mechanism can be attributed to the formation of a 2D bulk heterojunction of the two polymers within the interlayers of the LDH nanosheets. Furthermore, flexible UTFs on polyethylene terephthalate substrates are also fabricated, which exhibit excellent folding strength and electrical stability.

Myostatin in black Muscovy duck (Cairina moschata): full-length cDNA cloning and age-dependent mRNA expression compared with IGF-I

Insulin-like growth factor-I (IGF-I) and myostatin (MSTN) are a pair of critical positive and negative growth regulators. The aim of the current study was to examine the age-dependent and muscle-specific expression of IGF-I and MSTN mRNAs in black Muscovy ducks in order to understand their roles in regulating the postnatal muscle growth of domestic ducks. The full-length cDNA of the black Muscovy duck MSTN gene was cloned and the age-dependent mRNA expression profile was compared with that of the IGF-I mRNA in skeletal muscles. The cDNA sequence of the MSTN gene was 1128 bp in length and encodes 375 amino acids, with more than 94.9% homology with poultry MSTN genes, and 83.0-92.0% homology with that of human and mammals (accession: KR006339.1). The IGF-I and MSTN mRNA expression exhibited opposite trends in age-dependency and in different muscles: IGF-I mRNA level was high in the early postnatal stage and low in the late mature stage, corresponding positively to growth; while the MSTN mRNA was low in the early stage, increased gradually and reached the highest level in mature muscles, and was negatively related to muscle growth. In the breast muscles, IGF-I mRNA was much higher than in the leg muscles; the opposite effect was seen in MSTN mRNA. These data suggest that the relative expression levels of IGF-I and MSTN are essential determinants in the temporal and muscle-specific regulation of postnatal skeletal muscle growth in Muscovy duck and possibly in other poultry species as well.

In vivo fluorescence imaging of hepatocellular carcinoma xenograft using near-infrared labeled epidermal growth factor receptor (EGFR) peptide

Minimally-invasive surgery of hepatocellular carcinoma (HCC) can be limited by poor tumor visualization with white light. We demonstrate systemic administration of a Cy5.5-labeled peptide specific for epidermal growth factor receptor (EGFR) to target HCC in vivo in a mouse xenograft model. We attached a compact imaging module to the proximal end of a medical laparoscope to collect near-infrared fluorescence and reflectance images concurrently at 15 frames/sec. We measured a mean target-to-background ratio of 2.99 ± 0.22 from 13 surgically exposed subcutaneous human HCC tumors in vivo in 5 mice. This integrated imaging methodology is promising to guide laparoscopic resection of HCC.

A luminescent ultrathin film with reversible sensing toward pressure

A flexible ultrathin film based on alternate assembly of a sodium polyacrylate (PAA) modified styrylbiphenyl derivative (BTBS) and layered double hydroxide nanosheets is fabricated, which exhibits pressure-responsive photoluminescence with a high sensitivity and good reversibility.