Solution-Processed Multiferroic Thin-Films with Large Magnetoelectric Coupling at Room-Temperature

Experimental realization of thin films with a significant room-temperature magnetoelectric coupling coefficient, α_ME, in the absence of an external DC magnetic field, has been thus far elusive. Here, a large coupling coefficient of 750 ± 30 mV Oe^-1 cm^-1 is reported for multiferroic polymer nanocomposites (MPCs) thin-films in the absence of an external DC magnetic field. The MPCs are based on PMMA-grafted cobalt-ferrite nanoparticles uniformly dispersed in the piezoelectric polymer poly(vinylidene fluoride-co-trifluoroethylene, P(VDF-TrFE). It is shown that nanoparticle agglomeration plays a detrimental role and significantly reduces α_ME. Surface functionalization of the nanoparticles by grafting a layer of poly(methyl methacrylate) (PMMA) via atom transfer radical polymerization (ATRP) renders the nanoparticle miscible with P(VDF-TRFE) matrix, thus enabling their uniform dispersion in the matrix even in submicrometer thin films. Uniform dispersion yields maximized interfacial interactions between the ferromagnetic nanoparticles and the piezoelectric polymer matrix leading to the experimental demonstration of large α_ME values in solution-processed thin films, which can be exploited in flexible and printable multiferroic electronic devices for sensing and memory applications.

Paper-based broadband flexible photodetectors with van der Waals materials

Layered metal chalcogenide materials are exceptionally appealing in optoelectronic devices thanks to their extraordinary optical properties. Recently, their application as flexible and wearable photodetectors have received a lot of attention. Herein, broadband and high-performance paper-based PDs were established in a very facile and inexpensive method by rubbing molybdenum disulfide and titanium trisulfide crystals on papers. Transferred layers were characterized by SEM, EDX mapping, and Raman analyses, and their optoelectronic properties were evaluated in a wavelength range of 405–810 nm. Although the highest and lowest photoresponsivities were respectively measured for TiS₃ (1.50 mA/W) and MoS₂ (1.13 μA/W) PDs, the TiS₃–MoS₂ heterostructure not only had a significant photoresponsivity but also showed the highest on/off ratio (1.82) and fast response time (0.96 s) compared with two other PDs. This advantage is due to the band offset formation at the heterojunction, which efficiently separates the photogenerated electron–hole pairs within the heterostructure. Numerical simulation of the introduced PDs also confirmed the superiority of TiS₃–MoS₂ heterostructure over the other two PDs and exhibited a good agreement with the experimental results. Finally, MoS₂ PD demonstrated very high flexibility under applied strain, but TiS₃ based PDs suffered from its fragility and experience a remarkable drain current reduction at strain larger than ± 0.33%. However, at lower strains, all PDs displayed acceptable performances.

Human study on cancer diagnostic probe (CDP) for real-time excising of breast positive cavity side margins based on tracing hypoxia glycolysis; checking diagnostic accuracy in non-neoadjuvant cases

BACKGROUND

Cancer diagnostic probe (CDP) had been developed to detect involved breast cavity side margins in real-time (Miripour et al. Bioeng Transl Med. e10236.). Here, we presented the results of the in vivo human model CDP studies on non-neoadjuvant cases.

METHODS

This study is a prospective, blind comparison to a gold standard, and the medical group recruited patients. CDP and frozen data were achieved before the permanent pathology experiment. The main outcome of the study is surgical margin status. From November 2018 to April 2020, 202 patients were registered, and 188 were assigned for the study. Breast-conserving surgery at any age or gender, re-surgery due to re-currency, or involved margins are acceptable. Patients must be non-neoadjuvant. The reliability of CDP scoring had been evaluated by the pathology of the scored IMs. Then, three models of the study were designed to compare CDP with the frozen sections. Receiver operating characteristic (ROC) curves and AUC were measured based on the permanent postoperative pathology gold standard.

RESULTS

A matched clinical diagnostic categorization between the pathological results of the tested IMs and response peaks of CDP on 113 cases, was reported (sensitivity = 97%, specificity = 89.3%, accuracy = 92%, positive predictive value (PPV) = 84.2%, and negative predictive value (NPV) = 98%). Study A showed the independent ability of CDP for IM scoring (sensitivity = 80%, specificity = 90%, accuracy = 90%, PPV = 22.2%, and NPV = 99.2%). Study B showed the complementary role of CDP to cover the missed lesions of frozen sections (sensitivity = 93.8%, specificity = 91%, accuracy = 91%, PPV = 55.6%, and NPV = 99.2%). Study C showed the ability of CDP in helping the pathologist to reduce his/her frozen miss judgment (specificity = 92%, accuracy = 93%, PPV = 42.1%, and NPV = 100%). Results were reported based on the post-surgical permanent pathology gold standard.

CONCLUSION

CDP scoring ability in intra-operative margin detection was verified on non-neoadjuvant breast cancer patients. Non-invasive real-time diagnosis of IMs with pathological values may make CDP a distinct tool with handheld equipment to increase the prognosis of breast cancer patients.

Electrochemical tracing of hypoxia glycolysis by carbon nanotube sensors, a new hallmark for intraoperative detection of suspicious margins to breast neoplasia

For most people, the first step in treatment is to take out the tumor (surgery), so precise and fast diagnosis of any sign of high-risk and neoplastic cells, especially in surgical cavity margins, is significant. The frozen pathology method is the conventional standard of intraoperative diagnosis, but the low number of slides prepared from non-fixed tissues prevents us from achieving a perfect diagnosis. Although many improvements in intraoperative margin detection were achieved, still real-time detection of neoplastic lesions is crucial to improving diagnostic quality. Functionalized carbon nanotubes grown on the electrode needles lively and selectively determine the H2O2 released from cancer/atypical cells through reverse Warburg effect and hypoxia assisted glycolysis pathways in a quantitative electrochemical manner. The study was carried out on cell lines, 57 in vivo mice models with breast cancer, and 258 fresh in vitro samples of breast cancer tumors. A real-time electrotechnical system, named cancer diagnostic probe (CDP) (US Patent Pub. No.: US 2018/02991 A1, US 2021/0007638 A1, and US 2021/0022650 A1 [publications], and US 10,786,188 B1 [granted]), has been developed to find pre-neoplastic/neoplastic cells in vivo in a quantitative electrochemical manner by tracing hypoxia glycolysis byproducts. Matched pathological evaluations with response peaks of CDP were found based on the presence of neoplasia (from atypia to invasive carcinoma) in live breast tissues. The ability of CDP to find neoplastic lesions in mice models in vivo and fresh breast tumors in vitro was verified with sensitivity and specificity of 95% and 97%, respectively. The system may help a surgeon assistant system for usage in the operating room after passing many trials and standard examinations in the future.

Hierarchically Structured Porous Piezoelectric Polymer Nanofibers for Energy Harvesting

Hierarchically porous piezoelectric polymer nanofibers are prepared through precise control over the thermodynamics and kinetics of liquid-liquid phase separation of nonsolvent (water) in poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) solution. Hierarchy is achieved by fabricating fibers with pores only on the surface of the fiber, or pores only inside the fiber with a closed surface, or pores that are homogeneously distributed in both the volume and surface of the nanofiber. For the fabrication of hierarchically porous nanofibers, guidelines are formulated. A detailed experimental and simulation study of the influence of different porosities on the electrical output of piezoelectric nanogenerators is presented. It is shown that bulk porosity significantly increases the power output of the comprising nanogenerator, whereas surface porosity deteriorates electrical performance. Finite element method simulations attribute the better performance to increased volumetric strain in bulk porous nanofibers.

Doping free transfer of graphene using aqueous ammonia flow

Doping-free transfer of graphene produced by catalytic chemical vapor deposition (CVD) on copper foil, is still a technical challenge since unintentional doping of the transferred graphene layer yields an uncontrolled shift of Dirac point in graphene-based field-effect transistors (FETs). Typically, CVD graphene is released from the growth template by etching of the template, i.e. copper. During the etching process, ions adhere to the graphene layer resulting in unintentional doping. We demonstrate that washing a CVD graphene layer in an aqueous ammonia flow bath after etching copper, removes the majority of the unintentional dopants. FETs fabricated from graphene after washing in DI-water display a large scattering in Dirac bias with lowered mobility. In contrast, FETs from graphene that is washed in ammonia furnish better performance with high geometrically normalized mobility exceeding 2.4 × 10⁴ cm² V⁻¹ s⁻¹, balanced transport and a Dirac voltage near zero. We attribute the improved FET behavior to effective removal of the ions with a typical density of 4 × 10¹² cm⁻² from the graphene layer.

The paper addresses the technical challenge of producing doping-free transferred graphene layers produced by catalytic chemical vapor deposition (CVD), thereby preventing uncontrolled shift of the Dirac point in comprising field-effect transistors.

Electrochemical approach for monitoring the effect of anti tubulin drugs on breast cancer cells based on silicon nanograss electrodes

One of the most interested molecular research in the field of cancer detection is the mechanism of drug effect on cancer cells. Translating molecular evidence into electrochemical profiles would open new opportunities in cancer research. In this manner, applying nanostructures with anomalous physical and chemical properties as well as biocompatibility would be a suitable choice for the cell based electrochemical sensing. Silicon based nanostructure are the most interested nanomaterials used in electrochemical biosensors because of their compatibility with electronic fabrication process and well engineering in size and electrical properties. Here we apply silicon nanograss (SiNG) probing electrodes produced by reactive ion etching (RIE) on silicon wafer to electrochemically diagnose the effect of anticancer drugs on breast tumor cells. Paclitaxel (PTX) and mebendazole (MBZ) drugs have been used as polymerizing and depolymerizing agents of microtubules. PTX would perturb the anodic/cathodic responses of the cell-covered biosensor by binding phosphate groups to deformed proteins due to extracellular signal-regulated kinase (ERK(1/2)) pathway. MBZ induces accumulation of Cytochrome C in cytoplasm. Reduction of the mentioned agents in cytosol would change the ionic state of the cells monitored by silicon nanograss working electrodes (SiNGWEs). By extending the contacts with cancer cells, SiNGWEs can detect minor signal transduction and bio recognition events, resulting in precise biosensing. Effects of MBZ and PTX drugs, (with the concentrations of 2 nM and 0.1 nM, respectively) on electrochemical activity of MCF-7 cells are successfully recorded which are corroborated by confocal and flow cytometry assays.

Postsynaptic alpha 2-adrenoceptors mediate melanosome aggregation in melanophores of the white-spotted rabbitfish (Siganus canaliculatus)

The present investigation was undertaken to study the nature of neuro-melanophore junction in the white-spotted rabbit fish Siganus canaliculatus. In vitro experiments using split fin preparation indicated that melanophores of S. canaliculatus are highly responsive to potassium ions and adrenergic agonists. Potassium ions and the adrenergic agonists induced prompt melanosome aggregation that could be competitively blocked by yohimbine (alpha-2 specific adrenergic antagonist) and phentolamine (non-specific alpha adrenergic antagonist). The melanophore responses to repeated potassium stimulation (up to 20 stimuli) did not show any sign of fatigue. However, statistically significant enhancement was observed in responses to potassium that followed the first five stimulations. Adrenergic agonists acted in a time and concentration-dependent manner and their relative potency had the following rank order: clonidine (alpha-2 specific agonist) > norepinephrine (non-specific adrenergic agonist) > phenylephrine (alpha-1 specific agonist) > methoxamine (alpha-1-specific agonist). Yohimbine exerted a more potent inhibiting effect on norepinephrine induced melanosome aggregation compared to phentolamine. Prazosine (alpha-1 specific antagonist) had no effect on such aggregation. Chemically denervated melanophores displayed hypersensitivity to alpha-adrenergic agonists but were refractive to potassium ion stimulation. The refractivity of denervated melanophores to potassium indicates the effect of potassium ion is not direct on melanophores but it is rather through depolarization effect of potassium on the neuro-melanophore peripheral sympathetic fibers and hence release of norepinephrine. In denervated melanophores, similar to intact melanophores, only phentolamine and yohimbine but not prazosine, significantly inhibited melanosome aggregation effect of norepinephrine, indicating that norepinephrine effect is through postsynaptic alpha-2 adrenoceptors. The present data demonstrate that the nature of melanophore innervation in this teleost is adrenergic and neuro-melanophore signals mediating melanosome aggregation are transmitted through alpha-2 postsynaptic adrenoceptors.

Glomerulosclerosis as a determinant of posttransplant function of older donor renal allografts

Transplantation of kidneys from older donors is being advocated to expand the organ donor pool. However, the prevalence of atherosclerosis and age-induced renal structural alterations account for the variable function of allografts procured from these older donors. Pretransplant biopsies are sometimes used to evaluate kidneys from older donors, but to date there are no defined criteria correlating the extent of structural alterations in these kidneys to subsequent function. We investigated the effect of glomerulosclerosis, a marker for nephrosclerosis, on graft outcome. Sixty-five baseline biopsies of kidney allografts were retrospectively analyzed to identify a referent point of glomerulosclerosis that correlated with inferior graft outcome. Age and death from nontraumatic cerebrovascular injuries were the main correlates for donor glomerulosclerosis (P < 0.001). Allografts with poor function at 6 months defined as serum creatinine > 2.5 mg/dl (n = 13) or nephrectomy (n = 4) had a mean of 20% glomerulosclerosis at the time of implantation compared with only 2% sclerosis in allografts with good function (P < 0.05). Delayed graft function occurred in 22% and 33% of recipients with no glomerulosclerosis and those with less than 20% glomerulosclerosis, respectively. In contrast, patients receiving kidneys with > 20% sclerosis had an 87% incidence of delayed function (P < 0.05). Moreover, graft loss occurred in 7% of recipients of kidneys with less than 20% sclerosis and in 38% of recipients with > 20% sclerosis (P < 0.04). Measurements of serum creatinine in the donors did not distinguish the different degrees of glomerulosclerosis found on biopsy. Our data indicate that donor glomerulosclerosis greater than 20% increases the risk of delayed graft function and poor outcome of transplanted kidneys. Therefore, we advocate the use of routine biopsies of kidneys from older (> 50 yrs) donors and those donors with nontraumatic cerebrovascular accidents, despite seemingly normal preprocurement serum creatinine.

The effect of Rhazya stricta on glucose homeostasis in normal and streptozotocin diabetic rats

The effect of R. stricta water extract on glucose homeostasis was studied in normal and streptozotocin diabetic rats. R. stricta had no effect on fasting glucose levels in normal and diabetic rats up to 7 h after its oral administration. In normal and diabetic rats R. stricta did not produce any significant effect on an oral glucose tolerance test (OGTT). Chronic administration of R. stricta in drinking water for 37 days did not produce any effect on the parameters of glucose homeostasis studied (plasma glucose, body weight, feed and fluid intake and plasma fructosamine) in the normal or diabetic phase of the experiment. The LD50 of R. stricta in mice was 2.36 g/kg body weight of the lyophilised extract and a daily administration of R. stricta to rats for 5 days did not produce any signs of organ damage.

Pharmacokinetics of tobramycin in the camel

The pharmacokinetics of tobramycin were determined in six healthy camels (Camelus dromedarius) following the intravenous (i.v.) and intramuscular (i.m.) administration of single doses of tobramycin sulphate (40 mg/ml). The half-life to tobramycin was 189 +/- 21 min and the mean residence time was 254 +/- 26 min. The apparent volume of distribution (area method) was 245 +/- 21 ml/kg, while volume of the central compartment of the two-compartment pharmacokinetic model was 110 +/- 12 ml/kg. The clearance (systemic) of tobramycin was 0.90 +/- 0.10 ml/min/kg. Values of the pharmacokinetic parameters suggest that glomerular filtration rate is lower in camels than in other ruminant species, horses, dogs and cats. Following i.m. administration of the dose (1.0 mg/kg), the drug was rapidly absorbed with peak serum concentration of 3.32 +/- 0.59 micrograms/ml at 20-30 min; the absorption half-life was 3.9 +/- 0.9 min. The systemic availability of tobramycin was 90.7 +/- 14.4%. The apparent half-life was 201 +/- 40 min, which was not significantly longer than the half-life following i.v. administration of the drug. Based on the pharmacokinetic values obtained in this study, a dosing rate of 2.5 mg/kg administered by i.m. injection at 12-h intervals can be recommended. This dosage regimen should achieve an average steady state serum concentration of 4 micrograms/ml with peak serum concentration approaching, but not exceeding, 10 micrograms/ml.

Structure of the guinea-pig trachea at rest and in contraction

The trachea of the guinea-pig measures about 47.5 mm in situ, and it shrinks to 38 mm when excised. It can be stretched to the in situ length with a load of 2-4 grams. The transverse area of its lumen measures about 4.5 mm2 in the cervical portion, whereas in the lowermost thoracic portion it measures 2.8 mm2, a difference of 37%. The lumen has an oval shape with the transverse diameter always exceeding the sagittal diameter. The separation between the ends of a cartilage in the dorsal region of the trachea is greater in the cervical than in the thoracic region. Elastic fibres are abundant in the tunica propria and run longitudinally; the collagen is in some areas arranged with a criss-cross pattern. The muscle is inserted on the concave aspect of each cartilage at some distance from the ends of the cartilage and it is therefore much longer than the gap between cartilage ends. Upon contraction in vitro (induced by carbachol) the muscle shortens by about 50%; there is a marked decrease of the transverse diameter of the trachea, and a certain decrease also of the sagittal diameter due to a straightening of the muscle and a change in shape and a movement of the mucosa. The cartilage ends are brought together and in the thoracic region they are bent and overlap extensively. The lumen of the trachea becomes circular and its area is reduced to 2.2 mm2 in the cervical portion and 1.7 mm2 in the thoracic portion.