The effect of platelet-rich fibrin, platelet-rich plasma, and concentrated growth factor in the repair of full thickness rotator cuff tears

BACKGROUND

Rotator cuff lesions rank among the prevalent causes of shoulder pain. Combining surgical interventions with growth factors, scaffolds, and stem cell therapies can effectively decrease the likelihood of rotator cuff repair recurrence. Platelet-rich plasma (PRP), platelet-rich fibrin (PRF), and concentrated growth factor (CGF), isolated from blood and rich in growth factors, have a critical role in cell migration, cell proliferation, and angiogenesis during the tissue regeneration process. Investigations have further substantiated the beneficial impact of PRP and PRF on the biomechanical and histologic attributes of the tendon-bone interface. We aimed to investigate the effectiveness of CGF compared with PRF and PRP in the repair of rotator cuff lesions as a new treatment strategy.

METHODS

Incision was performed on both shoulder regions of 21 adult rabbits. After 8 weeks, both shoulders of the rabbits were repaired by suturing. PRF and CGF were administered to 2 separate groups along with the repair. Tissues were collected for biomechanical measurements and histologic evaluations.

RESULTS

Histologically, CGF, PRF, and PRP showed similar results to the healthy control group. The level of improvement was significant in the PRF and PRP groups. In the PRF group, the distribution of Ki67 (+), CD31 (+), and CD34 (+) cells was determined intensely in the tendon-bone junction regions. Apoptotic cells increased significantly in the repair group compared with the healthy group, whereas fewer apoptotic cells were found in the PRF-, PRP-, and CGF-applied groups. In the biomechanical results, no statistical difference was recorded among the groups.

CONCLUSION

The use of PRF, PRP, and CGF in rotator cuff repair shows promise in shortening the treatment period and preventing the recurrence of rotator cuff lesions.

Comparative analysis of effects of conditioned mediums obtained from 2D or 3D cultured mesenchymal stem cells on kidney functions of diabetic rats: Early intervention could potentiate transdifferentiation of parietal epithelial cell into podocyte precursors

AIM

The secretome of mesenchymal stem cells (MSCs) could be a potential therapeutic intervention for diabetes and associated complications like nephropathy. This study aims to evaluate the effects of conditioned mediums (CMs) collected from umbilical cord-derived MSCs incubated under 2-dimensional (2D) or 3D culture conditions on kidney functions of rats with type-I diabetes (T1D).

MAIN METHODS

Sprague-Dawley rats were treated with 20 mg/kg streptozocin for 5 consecutive days to induce T1D, and 12 doses of CMs were applied intraperitoneally for 4 weeks. The therapeutic effects of CMs were comparatively investigated by biochemical, physical, histopathological, and immunohistochemical analysis.

KEY FINDINGS

3D-CM had significantly higher total protein concentration than the 2D-CM Albumin/creatinine ratios of both treatment groups were significantly improved in comparison to diabetes. Light microscopic evaluations showed that glomerular and cortical tubular damages were significantly ameliorated in only the 3D-CM applied group compared to the diabetes group, which were correlated with transmission electron microscopic observations. The nephrin and synaptopodin expressions increased in both treatment groups compared to diabetes. The WT1, Ki-67, and active caspase-3 expressions in glomeruli and parietal layers of the treatment groups suggest that both types of CMs suppress apoptosis and promote possible parietal epithelial cells' (PECs') transdifferentiation towards podocyte precursor cells by switching on WT1 expression in parietal layer rather than inducing new cell proliferation.

SIGNIFICANCE

3D-CM was found to be more effective in improving kidney functions than 2D-CM by ameliorating glomerular damage through the possible mechanism of transdifferentiation of PECs into podocyte precursors and suppressing glomerular apoptosis.

Preconditioning of human umbilical cord mesenchymal stem cells with deferoxamine potentiates the capacity of the secretome released from the cells and promotes immunomodulation and beta cell regeneration in a rat model of type 1 diabetes

This study aimed to examine the effects of the secretome released by human umbilical cord-mesenchymal stem cells (MSC) as a result of preconditioning with deferoxamine (DFX), a hypoxia mimetic agent, on type 1 diabetes (T1D), by comparing it with the secretome produced by untreated MSCs. Initially, the levels of total protein, IL4, IL10, IL17, and IFNγ in the conditioned medium (CM) obtained from MSCs subjected to preconditioning with 150 µM DFX (DFX-CM) were analyzed in comparison to CM derived from untreated MSCs (N-CM). Subsequently, the CMs were administered to rats with T1D within a specific treatment plan. Following the sacrification, immunomodulation was evaluated by measuring serum cytokine levels and assessing the regulatory T cell (Treg) ratio in spleen mononuclear cells. Additionally, β-cell mass was determined in the islets by immunohistochemical labeling of NK6 Homeobox 1 (Nkx6.1), Pancreatic duodenal homeobox-1 (Pdx1), and insulin antibodies in pancreatic sections. In vitro findings indicated that the secretome levels of MSCs were enhanced by preconditioning with DFX. In vivo, the use of DFX-CM significantly increased the Treg population, and accordingly, the level of inflammatory cytokines decreased. In β-cell marker labeling, D + DFX-CM showed significantly increased PDX1 and insulin immunoreactivity. In conclusion, while the factors released by MSCs without external stimulation had limited therapeutic effects, substantial improvements in immunomodulation and β-cell regeneration were seen with DFX-preconditioned cell-derived CM.

Ultra-thin double-layered hexagonal CuI: strain tunable properties and robust semiconducting behavior

In this study, the freestanding form of ultra-thin CuI crystals, which have recently been synthesized experimentally, and their strain-dependent properties are investigated by means of density functional theory calculations. Structural optimizations show that CuI crystallizes in a double-layered hexagonal crystal (DLHC) structure. While phonon calculations predict that DLHC CuI crystals are dynamically stable, subsequent vibrational spectrum analyzes reveal that this structure has four unique Raman-active modes, allowing it to be easily distinguished from similar ultra-thin two-dimensional materials. Electronically, DLHC CuI is found to be a semiconductor with a direct band gap of 3.24 eV which is larger than that of its wurtzite and zincblende phases. Furthermore, it is found that in both armchair (AC) and zigzag (ZZ) orientations the elastic instabilities occur over the high strain strengths indicating the soft nature of CuI layer. In addition, the stress-strain curve along the AC direction reveal that DLHC CuI undergoes a structural phase transition between the 4% and 5% tensile uniaxial strains as indicated by a sudden drop of the stress in the lattice. Moreover, the phonon band dispersions show that the phononic instability occurs at much smaller strain along the ZZ direction than that of along the AC direction. Furthermore, the external strain direction can be deduced from the predicted Raman spectra through the splitting rates of the doubly degenerate in-plane vibrations. The mobility of the hole carriers display highly anisotropic characteristic as the applied strain reaches 5% along the AC direction. Due to its anomalous strain-dependent electronic features and elastically soft nature, DLHC of CuI is a potential candidate for future electro-mechanical applications.

Empagliflozin and sacubitril/valsartan reverse methotrexate cardiotoxicity by repressing oxidative stress and hypoxia in heart embryonic H9c2 cardiomyocytes - the role of morphology of mitochondria observed on electron microscopy

OBJECTIVE

Oxidative stress and hypoxia play an important role in the pathogenesis of various cardiovascular diseases. We aimed to evaluate the effectiveness of sacubitril/valsartan (S/V) and Empagliflozin (EMPA) on hypoxia-inducible factor-1α (HIF-1α) and oxidative stress in H9c2 rat embryonic cardiomyocyte cells.

MATERIALS AND METHODS

BH9c2 cardiomyocyte cells were treated with methotrexate (MTX) (10-0.156 μM), empagliflozin (EMPA; 10-0.153 µM) and sacubitril/valsartan (S/V; 100-1.062 µM) for 24, 48 and 72 h. The half maximum inhibitory concentration (IC50) and half maximum excitation concentration (EC50) values of MTX, EMPA and S/V were determined. The cells under investigation were exposed to 2.2 μM MTX before treatment with 2 μM EMPA and 25 μM S/V. The cell viability, lipid peroxidation, oxidation of proteins and antioxidant parameters were measured while morphological changes were also observed by transmission electron microscopy (TEM).

RESULTS

The results showed that treatment with 2 µM EMPA, 25 µM S/V or their combination produced a protective effect against the reduction in cell viability caused by 2.2 µM MTX.  While HIF-1α levels plunged to their lowest with S/V treatment, oxidant parameters dipped, and antioxidant parameters soared to their highest level with S/V and EMPA combination treatment. A negative correlation was found between HIF-1α and total antioxidant capacity in the S/V treatment group.

CONCLUSIONS

A significant decrease in HIF-1α and oxidant molecules together with an enhancement in antioxidant molecules and normalization of the mitochondria morphology as observed on electron microscopy in S/V and EMPA-treated cells were detected. Although S/V and EMPA have both protective effects against cardiac ischemia and oxidative damage, this effect may be increased more with S/V treatment alone compared to combined treatment.

Human ovarian granulosa cells use clathrin-mediated endocytosis for LDL uptake: immunocytochemical and electron microscopic study

The steroidogenic activity of the granulosa cells is important for the reproductive cycle, and lipoproteins are involved in this process. The clathrin-mediated endocytosis pathway for LDL transport is considered to be the main one in eukaryotic cells. However, there are no studies that elucidate LDL internalization in human granulosa cells clarifying whether the clathrin-mediated endocytic pathway is functional in this process. The aim of this study is to investigate the role of clathrin and v-SNARE proteins in the formation of vesicles in human granulosa cells. In this study, the COV434 human granulosa cells were cultured and divided into four groups where in some of the groups Dil-conjugated LDL and Icarugamycin (ICA) a clathrin-mediated endocytosis inhibitor were added. From the collected mediums pregnenolone and progesterone levels were measured using ELISA. Oil red O staining was performed to show the intracellular lipids in the cells. Clathrin-coated vesicles believed to be responsible for carrying LDL, and v-SNARE proteins that direct the vesicles to their target molecules were also labeled and investigated by histological and ultrastructural methods. Our results show that human granulosa cells as well use the LDL cholesterol for steroid biosynthesis and they may prefer the clathrin-mediated endocytotic pathway to internalize it.

The Distribution of Foxp3 and CD68 in Preeclamptic and Healthy Placentas: A Histomorphological Evaluation

Preeclampsia is a complication of pregnancy that affects 3-5% of pregnancies and is one of the major causes of maternal/neonatal mortality and morbidities worldwide. We aimed to investigate the distribution of Foxp3+ regulatory T-cells and CD68+ Hofbauer cells in the placenta of preeclamptic and healthy pregnant women with a special focus on correlating these findings with placental histology. Decidua and chorionic villi of the placenta obtained from healthy and preeclamptic pregnancies were evaluated in full-thickness sections. Sections were stained with hematoxylin and eosin and Masson's trichrome and immunostained for Foxp3 and CD68 for histological analyses. The total histomorphological score for placentas was found to be higher in preeclamptic placentas than that in the controls. The CD68 immunoreactivity was higher in the chorionic villi of preeclamptic placentas than that in the controls. The immunoreactivity of Foxp3 was found widely distributed within the decidua in both the groups and did not differ significantly. Interestingly, Foxp3 immunoreactivity in the chorionic villi was found mainly in the villous core and, to a lesser extent, in the syncytiotrophoblasts. We found no significant relation between Foxp3 expressions and morphological changes observed in preeclamptic placentas. Although extensive research is being carried out regarding the pathophysiology of preeclampsia, the findings are still controversial.

Effects of Chronically Exogenous Oxytocin on Ovary and Uterus: A Comparison of Intraperitoneal and Intranasal Administration

Oxytocin (OT) has been studied as a therapeutic neuropeptide in various diseases, but its effect on the ovary and uterus is not fully known. This study investigates the effects of intranasal and intraperitoneal OT administration on ovaries and uterus in rats. Four experimental groups were created using 7-week-old Sprague Dawley-type female rats: Control (Ctrl), oxytocin-intraperitoneal (0.1µg/day) (OT-IP), oxytocin-intranasal (0.05µg/day) (OT-IN1), and oxytocin-intranasal (0.1µg/day) (OT-IN2). The blood, the ovarian, and the uterus were collected at the end of the 28th day of OT administration. Afterward, histological and biochemical analyses were performed. We observed that the Graaf follicles were higher in both OT-IN2 and OT-IP groups compared to the Ctrl group. Moreover, the corpus luteum was increased only in the OT-IN2 group. Ki-67, CD31, VEGF, and TGF-ß immunostaining showed no significant change in the ovary. In contrast, Ki-67, VEGF, and OTR expressions demonstrated significant alterations in the uterus. Furthermore, TGF-ß immunohistochemistry and the histopathologic score did not reveal the statistical change in the uterus. Serum hormone levels showed that the anti-Müllerian hormone increased in all OT groups vs. the Ctrl. OT-IP showed an increment of follicle-stimulating hormone and estradiol decrement. There was a decrease in serum E2 levels, although the Graafian follicle number increased in OT-IP groups compared to the Ctrl group. However, luteinizing hormone, gonadotropin-releasing hormone, progesterone, testosterone, OT levels, and oxidative stress index did not reveal any statistical difference. Accordingly, the intranasal route may have beneficial effects compared to the intraperitoneal route regarding exogenous OT administration-related studies. In conclusion, we reported that exogenous OT increases the follicle reserve and may cause histological changes in the reproductive system of female rats.

Protective Effects of Intranasally Administrated Oxytocin-Loaded Nanoparticles on Pentylenetetrazole-Kindling Epilepsy in Terms of Seizure Severity, Memory, Neurogenesis, and Neuronal Damage

Pentylenetetrazole (PTZ)-induced kindling is an animal model for studying human temporal lobe epilepsy (TLE), which is characterized by alterations of hippocampal neurons and memory. Although the intranasal (IN) administration of oxytocin (OT) has limited efficiency, nanoparticles (NPs) are a promising candidate to deliver OT to the brain. However, there are very limited data on epilepsy research about oxytocin-loaded nanoparticles (NP-OTs). The aim of this study is to investigate the effects of IN administration of chronic NP-OTs on the hippocampus of PTZ-induced male epileptic rats in terms of seizure severity, memory, neurogenesis, and neuronal damage. Saline/OT/NP-OTs were administrated to both control (Ctrl) and PTZ groups intranasally. Consequently, saline and PTZ were injected, respectively, 25 times every 48 h. Then, seizure severity (score and latency) was calculated for the PTZ groups. A spatial working memory evaluation test (SWMET) was performed after the last injection. Hippocampus histopathology, neurogenesis, and apoptosis were demonstrated. Serum total antioxidant status (TAS) and total oxidant status (TOS) levels and the oxidative stress index (OSI) were measured. We showed that OTs and NP-OTs prevented the kindling development and had positive effects on seizure severity. SWMET-related behaviors were also recovered in the PTZ + NP-OT group. A significant increase of neurogenesis and decrease of apoptosis in the hippocampus of the PTZ + NP-OT group were observed, while OTs and NP-OTs had protective effects against PTZ-induced damage to hippocampal neurons. Our results indicate that the chronic administration of NP-OTs may have positive effects on hippocampal damage via increasing neurogenesis and decreasing apoptosis and seizure severity.

Interface-dependent phononic and optical properties of GeO/MoSO heterostructures

The interface-dependent electronic, vibrational, piezoelectric, and optical properties of van der Waals heterobilayers, formed by buckled GeO (b-GeO) and Janus MoSO structures, are investigated by means of first-principles calculations. The electronic band dispersions show that O/Ge and S/O interface formations result in a type-II band alignment with direct and indirect band gaps, respectively. In contrast, O/O and S/Ge interfaces give rise to the formation of a type-I band alignment with an indirect band gap. By considering the Bethe-Salpeter equation (BSE) on top of G₀W₀ approximation, it is shown that different interfaces can be distinguished from each other by means of the optical absorption spectra as a consequence of the band alignments. Additionally, the low- and high-frequency regimes of the Raman spectra are also different for each interface type. The alignment of the individual dipoles, which is interface-dependent, either weakens or strengthens the net dipole of the heterobilayers and results in tunable piezoelectric coefficients. The results indicate that the possible heterobilayers of b-GeO/MoSO asymmetric structures possess various electronic, optical, and piezoelectric properties arising from the different interface formations and can be distinguished by means of various spectroscopic techniques.

Real world results of venetoclax combined with hypomethylating agents in relapsed/refractory AML

OBJECTIVE

Relapsed/refractory AML cases are much more resistant to chemotherapy. Venetoclax is a highly sensitive BCL-2 inhibitor. It was aimed to evaluate the effects of venetoclax therapy on real-world R/R AML survival outcomes, the effects of the cytogenetic characteristics of the patients and previous clinical applications on treatment response, and venetoclax treatment toxicity.

PATIENTS AND METHODS

The study included patients who only received a venetoclax-based salvage on R/R AML patients from Turkey. The study included a total of 62 patients from 6 different centers in Turkey. Response to 2 cycles of venetoclax treatment was assessed by bone marrow blast rate. The demographic data, cytogenetic characteristics, AML type, MDS type, response rates and overall survival of the patients after venetoclax combination treatment were assessed. Median age of the patients was 65 (19-85). Mean number of prior treatments was 2.67 ±1.75.

RESULTS

13 patients (21%) had a history of allogenic stem cell transplantation. 58 (93.5%) had received HMA therapy before venetoclax. 36 patients (58.1%) had de-novo AML, and 25 (40.3%) previously had MDS. Treatment response was evaluated as complete remission (n = 21, 33.9%), partial response (n = 17, 27.4%), and treatment failure (n = 24, 38.7%). Patients in the TF group were significantly more likely to have poor cytogenetic and to have received allogeneic transplants. The mean estimated overall survival after the venetoclax treatment was 9.13 ± 0.75 months.

CONCLUSIONS

The study population consisted of a group of patients who had relapsed or primary refractory disease with poor prognosis, despite numerous rounds of chemotherapy. It is our belief that the high response rates obtained with the combination of venetoclax/HMA, and having obtained positive results with poor risk patients, indicated a promising perspective for R/R AML patients.

Vibrational and optical identification of GeO2 and GeO single layers: a first-principles study

In the present work, the identification of two hexagonal phases of germanium oxides (namely GeO₂ and GeO) through the vibrational and optical properties is reported using density functional theory calculations. While structural optimizations show that single-layer GeO₂ and GeO crystallize in 1T and buckled phases, phonon band dispersions reveal the dynamical stability of each structure. First-order off-resonant Raman spectral predictions demonstrate that each free-standing single-layer possesses characteristic peaks that are representative for the identification of the germanium oxide phase. On the other hand, electronic band dispersion analysis shows the insulating and large-gap semiconducting nature of single-layer GeO₂ and GeO, respectively. Moreover, optical absorption, reflectance, and transmittance spectra obtained by means of G₀W₀-BSE calculations reveal the existence of tightly bound excitons in each phase, displaying strong optical absorption. Furthermore, the excitonic gaps are found to be at deep UV and visible portions of the spectrum, for GeO₂ and GeO crystals, with energies of 6.24 and 3.10 eV, respectively. In addition, at the prominent excitonic resonances, single-layers display high reflectivity with a zero transmittance, which is another indication of the strong light-matter interaction inside the crystal medium.

Primer malignant giant cell tumour of kidney: a case report

Osteoclast-like giant cell tumours of the kidney are extremely rare and usually accompanied by a conventional urothelial neoplasm such as papillary, transitional renal cell, or sarcomatoid carcinoma. Although they have morphological features similar to those of the giant cell tumours in the skeletal system, their counterparts in the urinary system show highly malignant features. Our case is the third primer malignant giant cell tumour of the kidney in the literature. The patient was a 50-year-old male and underwent nephroureterectomy for a mass of 18×14×13cm in his left kidney. However, the patient died in the second month postoperatively as a result of local recurrences and multiple distant metastases. The general condition of the patient deteriorated progressively; hence, he could not have any adjuvant therapy. Having more information about the pathological and clinical findings of these exceedingly rare tumours can help inform treatment steps.

Effects of transcranial electrical stimulation on episodic memory in physiological and pathological ageing

Memory for personally-relevant past events (episodic memory) is critical for activities of daily living. Decline in this type of declarative long-term memory is a common characteristic of healthy ageing, a process accelerated in patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD). Transcranial electrical stimulation (tES) has been used as a strategy to ameliorate episodic memory. Here, we critically review studies investigating whether tES may improve episodic memory in physiological and pathological ageing. Most of the studies suggest that tES over the prefrontal or temporoparietal cortices can have a positive effect on episodic memory, but the transfer to improvement of execution of daily living activities is still unknown. Further work is needed to better understand the mechanisms underlying the effects of stimulation, combine tES with neuroimaging and optimizing the dosing of stimulation. Future studies should also investigate the optimal timing of stimulation and the combination with medications to induce long-lasting beneficial effects in pathological ageing. More open science efforts should be done to improve rigor and reliability of tES in ageing research.

Stable single-layers of calcium halides (CaX2, X = F, Cl, Br, I)

By means of density functional theory based first-principles calculations, the structural, vibrational, and electronic properties of 1H- and 1T-phases of single-layer CaX₂ (X = F, Cl, Br, or I) structures are investigated. Our results reveal that both the 1H- and 1T-phases are dynamically stable in terms of their phonon band dispersions with the latter being the energetically favorable phase for all single-layers. In both phases of single-layer CaX₂ structures, significant phonon softening occurs as the atomic radius increases. In addition, each structural phase exhibits distinctive Raman active modes that enable one to characterize either the phase or the structure via Raman spectroscopy. The electronic band dispersions of single-layer CaX₂ structures reveal that all structures are indirect bandgap insulators with a decrease in bandgaps from fluorite to iodide crystals. Furthermore, the calculated linear elastic constants, in-plane stiffness, and Poisson ratio indicate the ultra-soft nature of CaX₂ single-layers, which is quite important for their nanoelastic applications. Overall, our study reveals that with their dynamically stable 1T- and 1H-phases, single-layers of CaX₂ crystals can be alternative ultra-thin insulators.

Defect tolerant and dimension dependent ferromagnetism in MnSe2

By performing density functional theory-based calculations, we investigate the structural, vibrational, electronic and magnetic properties of 2D monolayers, nanoribbons and quantum dots of MnSe₂.

Monolayer AsTe2 : Stable Robust Metal in 2D, 1D and 0D

The structural, phononic, and electronic properties of the monolayer structures of AsTe₂ are characterized by performing density functional theory (DFT) calculations. Total energy optimization and phonon calculations reveal that single layers of the 2H-AsTe₂ and 1T-AsTe₂ phases form dynamically stable crystal structures. Electronic structure analysis also shows that both 2H and 1T phases have nonmagnetic metallic character. It is also predicted that the metallic nature of the ultra-thin both 2H-AsTe₂ and 1T-AsTe₂ structures remain unchanged even under high biaxial strain values. For further examination of the dimensionality effect in the robust metallicity in 2D AsTe₂ phases, electronic characteristics of 1D nanoribbons and 0D quantum dots are also investigated. It is found that independent from the dimension and crystallographic orientations 0D and 1D structures of 2H- and 1T-AsTe₂ structures have metallic behavior. It is found that single layers of AsTe₂ are quite promising materials for nanodevice applications owing to the robust metallic character.

Bilayers of Janus WSSe: monitoring the stacking type via the vibrational spectrum

Motivated by the recent successful synthesis of Janus type single layers of transition metal dichalcogenides, we investigate the stability, vibrational and electronic properties of the Janus single layer structure of WSSe and its bilayers by means of density functional theory. The structural and vibrational analysis show that the Janus single layer of WSSe forms a dynamically stable structure in the 2H phase. Owing to its non-centrosymmetric structure, the Janus WSSe single layer has two in-plane (E) and two out-of-plane (A) Raman active phonon modes. The eigen-frequencies of the prominent Raman active modes are calculated to be 277 (A) and 322 (E) cm-1. Similar to single layer WS2 and WSe2, Janus WSSe is a direct band gap semiconductor that has two electronically different faces. In addition, the possible bilayer stacking orders of the Janus WSSe single layers are investigated. It is found that there are 3 stacking types of bilayer Janus WSSe and each stacking type has distinctive Raman characteristics in its vibrational spectrum. Our results show that thanks to the vibrational characteristics, which stem from the distinctive interlayer interactions at different sides, the stability and stacking types of the bilayer of WSSe Janus structure can be monitored.

Incremental Value of Magnetic Resonance Imaging in Further Characterizing Hypodense Mediastinal and Paracardiac Lesions Identified on Computed Tomography

Mediastinal and paracardiac lesions are usually first diagnosed on a chest radiograph or echocardiogram. Often, a computed tomography is obtained to further delineate these lesions. CT may be suboptimal for evaluation of enhancement characteristics and direct extension into the adjacent mediastinal structures. With its intrinsic superior soft-tissue characterization, magnetic resonance imaging (MRI) can better delineate these lesions, their internal tissue characteristics, and identify adhesion/invasion into adjacent structures. This pictorial essay provides a brief synopsis of the key MRI sequences and their utility in further characterizing mediastinal and paracardiac lesions.

Hydrogenated derivatives of hexacoordinated metallic Cu2Si monolayer

Herein, we carried out first-principles calculations based on density functional theory to investigate the effects of surface functionalization with hydrogen atoms on structural, dynamical and electronic properties of Cu₂Si monolayer. Pristine Cu₂Si, a metallic monolayer, has a planar hexacoordinate structure. Calculations revealed that the most favorable position of a single H atom on the Cu₂Si monolayer is at the top of a Si site. Derivatives of Cu₂Si monolayer with various H concentrations were investigated, and by performing phonon calculations, it was found that there are three stable hydrogenated structures. Specific heat of these monolayers was found to increase with the hydrogen concentration at temperatures higher than 100 K. Electronically, the hydrogenated derivatives of Cu₂Si monolayer preserve the metallic character.

Herein, we carried out first-principles calculations based on density functional theory to investigate the effects of surface functionalization with hydrogen atoms on structural, dynamical and electronic properties of Cu₂Si monolayer.

Hydrogenation-driven phase transition in single-layer TiSe2

First-principles calculations based on density-functional theory are used to investigate the effects of hydrogenation on the structural, vibrational, thermal and electronic properties of the charge density wave (CDW) phase of single-layer TiSe₂. It is found that hydrogenation of single-layer TiSe₂ is possible through adsorption of a H atom on each Se site. Our total energy and phonon calculations reveal that a structural phase transition occurs from the CDW phase to the T _d phase upon full hydrogenation. Fully hydrogenated TiSe₂ presents a direct gap semiconducting behavior with a band gap of 119 meV. Full hydrogenation also leads to a significant decrease in the heat capacity of single-layer TiSe₂.

Stable ultra-thin CdTe crystal: a robust direct gap semiconductor

Employing density functional theory based calculations, we investigate structural, vibrational and strain-dependent electronic properties of an ultra-thin CdTe crystal structure that can be derived from its bulk counterpart. It is found that this ultra-thin crystal has an 8-atom primitive unit cell with considerable surface reconstructions. Dynamic stability of the structure is predicted based on its calculated vibrational spectrum. Electronic band structure calculations reveal that both electrons and holes in single layer CdTe possess anisotropic in-plane masses and mobilities. Moreover, we show that the ultra-thin CdTe has some interesting electromechanical features, such as strain-dependent anisotropic variation of the band gap value, and its rapid increase under perpendicular compression. The direct band gap semiconducting nature of the ultra-thin CdTe crystal remains unchanged under all types of applied strain. With a robust and moderate direct band gap, single-layer CdTe is a promising material for nanoscale strain dependent device applications.

Diagnostic Utility of Chest Radiography in Predicting Long-Standing Systemic Arterial Hypertension

PURPOSE

To investigate the association between aortic arch width on frontal chest radiography and systemic hypertension.

METHODS

A total of 200 consecutive patients were included. Relationships between aortic arch width measurement on chest radiography and blood pressure measurement were investigated using Student's t -tests and Fisher's exact tests.

RESULTS

Twenty-five patients were normotensive (< 130/90 mmHg), and 175 were hypertensive. Using cut-off values, 136 patients had an aortic arch width ≥ 3.5 cm, and 65 had an aortic arch width ≥ 4 cm. We found a significant relationship between aortic arch width and hypertension (p < 0.001) as well between aortic arch width cut-off values of 3.5 cm and 4 cm and hypertension (p < 0.001 and p < 0.005, respectively). An aortic arch width ≥ 3.5 cm was associated with a positive likelihood ratio (LR) of 2.3, negative LR of 0.39, sensitivity of 73, specificity of 68, positive predictive value of 94, negative predictive value of 26.6, pretest odds of 7, posttest odds of 16, and posttest probability of 94%. An aortic arch width ≥ 4 cm was associated with a positive LR of 4.50, negative LR of 0.70, sensitivity of 36, specificity of 92, positive predictive value of 97, negative predictive value of 17, pretest odds of 7, posttest odds of 31.5, and posttest probability of 97%.

CONCLUSIONS

Aortic arch width measurement on chest radiography can be used to predict the presence of long-standing systemic arterial hypertension.

Few-layer MoS2 as nitrogen protective barrier

We report experimental and theoretical investigations of the observed barrier behavior of few-layer MoS₂ against nitrogenation. Owing to its low-strength shearing, low friction coefficient, and high lubricity, MoS₂ exhibits the demeanor of a natural N-resistant coating material. Raman spectroscopy is done to determine the coating capability of MoS₂ on graphene. Surface morphology of our MoS₂/graphene heterostructure is characterized by using optical microscopy, scanning electron microscopy, and atomic force microscopy. In addition, density functional theory-based calculations are performed to understand the energy barrier performance of MoS₂ against nitrogenation. The penetration of nitrogen atoms through a defect-free MoS₂ layer is prevented by a very high vertical diffusion barrier, indicating that MoS₂ can serve as a protective layer for the nitrogenation of graphene. Our experimental and theoretical results show that MoS₂ material can be used both as an efficient nanocoating material and as a nanoscale mask for selective nitrogenation of graphene layer.

Stability, electronic and phononic properties of β and 1T structures of SiTe x (x = 1, 2) and their vertical heterostructures

By performing first-principles calculations, we predict a novel, stable single layer phase of silicon ditelluride, 1T-[Formula: see text], and its possible vertical heterostructures with single layer β-SiTe. Structural optimization and phonon calculations reveal that 1T-[Formula: see text] structure has a dynamically stable ground state. Further analysis of the vibrational spectrum at the [Formula: see text] point shows that single layer 1T-[Formula: see text] has characteristic phonon modes at 80, 149, 191 and 294 [Formula: see text]. Electronic-band structure demonstrates that 1T-[Formula: see text] phase exhibits a nonmagnetic metallic ground state with a negligible intrinsic spin-orbit splitting. Moreover, it is shown that similar structural parameters of 1T-[Formula: see text] and existing β-SiTe phases allows construction of 1T-β heterostructures with a negligible lattice mismatch. In this regard, it is found that two energetically favorable stacking orders, namely AA and [Formula: see text]B, have distinctive shear and layer breathing phonon modes. It is important to note that the combination of semiconducting β-SiTe and metallic 1T-[Formula: see text] building blocks forms ultra-thin Schottky barriers that can be used in nanoscale optoelectronic device technologies.

Controlled growth mechanism of poly (3-hexylthiophene) nanowires

Synthesis of 1D-polymer nanowires by a self-assembly method using marginal solvents is an attractive technique. While the formation mechanism is poorly understood, this method is essential in order to control the growth of nanowires. Here we visualized the time-dependent assembly of poly (3-hexyl-thiophene-2,5-diyl) (P3HT) nanowires by atomic force microscopy and scanning tunneling microscopy. The assembly of P3HT nanowires was carried out at room temperature by mixing cyclohexanone (CHN), as a poor solvent, with polymer solution in 1,2-dichlorobenzene (DCB). Both π-π stacking and planarization, obtained at the mix volume ratio of P3HT (in DCB):CHN (10:7), were considered during the investigation. We find that the length of nanowires was determined by the ordering of polymers in the polymer repetition direction. Additionally, our density functional theory calculations revealed that the presence of DCB and CHN molecules that stabilize the structural distortions due to tail group of polymers was essential for the core-wire formation.

Structural changes in a Schiff base molecular assembly initiated by scanning tunneling microscopy tip

We report the controlled self-organization and switching of newly designed Schiff base (E)-4-((4-(phenylethynyl) benzylidene) amino) benzenethiol (EPBB) molecules on a Au (111) surface at room temperature. Scanning tunneling microscopy and spectroscopy (STM/STS) were used to image and analyze the conformational changes of the EPBB molecules. The conformational change of the molecules was induced by using the STM tip while increasing the tunneling current. The switching of a domain or island of molecules was shown to be induced by the STM tip during scanning. Unambiguous fingerprints of the switching mechanism were observed via STM/STS measurements. Surface-enhanced Raman scattering was employed, to control and identify quantitatively the switching mechanism of molecules in a monolayer. Density functional theory calculations were also performed in order to understand the microscopic details of the switching mechanism. These calculations revealed that the molecular switching behavior stemmed from the strong interaction of the EPBB molecules with the STM tip. Our approach to controlling intermolecular mechanics provides a path towards the bottom-up assembly of more sophisticated molecular machines.

Giant magnetic anisotropy in doped single layer molybdenum disulfide and fluorographene

Stable monolayer materials based on existing, well known and stable two-dimensional crystal fluorographene and molybdenum disulfide are predicted to exhibit a huge magnetocrystalline anisotropy when functionalized with adsorbed transition metal atoms at vacant sides. Ab initio calculations within the density-functional theory formalism were performed to investigate the adsorption of the transitional metals in a single S (or F) vacancy of monolayer molybdenum disulfide (or fluorographene). We found strong bonding of the transitional metal atoms to the vacant sites with binding energies ranging from 2.5 to 5.2 eV. Our calculations revealed that these systems with adsorbed metal atoms exhibit a magnetic anisotropy, specifically the structures including Os and Ir show a giant magnetocrystalline anisotropy energy of 31-101 meV. Our results demonstrate the possibility of obtaining stable monolayer materials with huge magnetocrystalline anisotropy based on preexisting, well known and stable two-dimensional crystals: fluorographene and molybdenum disulfide. We believe that the results obtained here are useful not only for deeper understanding of the origin of magnetocrystalline anisotropy but also for the design of monolayer optoelectronic devices with novel functionalities.

COPD patients with severe diffusion defect in carbon monoxide diffusing capacity predict a better outcome for pulmonary rehabilitation

PURPOSE

The aim of this study was to compare the effects of pulmonary rehabilitation (PR) on six-minute walk test (6mWT) between chronic obstructive pulmonary disease (COPD) patients with moderate or severe carbon monoxide diffusion defects. We also evaluated dyspnea sensation, pulmonary functions, blood gases analysis, quality of life parameters and psychological symptoms in both groups before and after pulmonary rehabilitation.

METHODS

Patients with COPD underwent a comprehensive 8-week out-patient PR program participated in this study. Patients grouped according to diffusion capacity as moderate or severe. Outcome measures were exercise capacity (6mWT), dyspnea sensation, pulmonary function tests, blood gases analysis, quality of life (QoL) and psychological symptoms.

RESULTS

A total of 68 patients enrolled in the study. Thirty-two (47%) of them had moderate diffusion defect [Tl_CO; 52 (47-61)mmol/kPa] and 36 (53%) of them had severe diffusion defect [Tl_CO; 29 (22-34)mmol/kPa]. At the end of the program, PaO₂ (p=0.001), Modified Medical Research Council dyspnea scale (p=0.001), 6mWT (p<0.001) and quality of life parameters improved significantly in both groups (p<0.05). Also the improvement in Dl_CO (p=0.04) value and FEV₁% (p=0.01) reached a statistically significant level in patients with severe diffusion defect. When comparing changes between groups, dyspnea reduced significantly in patients with severe diffusion defect (p=0.04).

CONCLUSION

Pulmonary rehabilitation improves oxygenation, severity of dyspnea, exercise capacity and quality of life independent of level of carbon monoxide diffusion capacity in patents with COPD. Furthermore pulmonary rehabilitation may improve Dl_CO values in COPD patients with severe diffusion defect.

Acute effects of grayanotoxin in rhododendron honey on kidney functions in rats

The aim of the study is to evaluate the acute biochemical and histological changes in rat kidneys after treatment with grayanotoxin (GTX) of rhododendron honey (RH). A total of 60 Sprague-Dawley female rats were divided into five groups of 12 rats each, one being a control group (group 1) and group 2 was treated with 0.015 mg/kg/bw of GTX standard preparation via intraperitoneal injection. Groups 3, 4, and 5 were given RH at doses of 0.1, 0.5, and 2.5 g/kg/bw, respectively, via oral gavage. Compared to the control group, significant increases were observed in glucose, blood urea nitrogen (BUN), and creatinine levels of the GTX-injected groups after 1 h. However, in low dose RH group, such an increase was not observed and had a normal appearance histologically. Therefore, low dose (1 g/kg/bw) of RH produces no acute adverse effects on renal functions of rats.

Primary squamous cell carcinoma of the ampulla of Vater: a case report

Background

Primary squamous cell carcinoma of the ampulla of Vater is a very rare type of tumor, and the prognosis is not well known mainly due to a limited number of cases reported. Here, we aimed to report a case with primary squamous cell carcinoma of the ampulla of Vater.

Case presentation

A 54-year-old woman presented with weight loss, jaundice, and pain in the epigastric and right upper quadrant of the abdomen. With extensive radiological imaging, the patient was diagnosed with periampullary tumor and Whipple’s procedure was performed. The immunohistochemical analyses supported the diagnosis of primary squamous cell carcinoma. The postoperative course was uneventful. The patient was discharged, and adjuvant chemotherapy was recommended.

Conclusion

Primary squamous cell carcinoma of the ampulla of Vater is a very rare histological type with an unclear pathogenesis. A better understanding of pathogenesis might be helpful in optimizing the treatment for this specific rare type of tumor.

Single layer PbI2: hydrogenation-driven reconstructions

By performing density functional theory-based calculations, we investigate how a hydrogen atom interacts with the surfaces of monolayer PbI₂ and how one- and two-side hydrogenation modifies its structural, electronic, and magnetic properties.

Can plateletcrit, an underestimated platelet parameter, be related with preterm labour?

OBJECTIVE

Noninvasive and simple markers are needed for the prediction of preterm delivery in women at risk for preterm labour. The aim of this study was to determine the value of platelet indices in the prediction of preterm delivery.

DESIGN

A retrospective study.

SETTING

Routine antenatal care in Zonguldak Bülent Ecevit University between 2008 and 2011.

SAMPLE

Ninety patients who delivered between 28 and 37 weeks of gestational age and 128 patients who delivered at term.

METHODS

Plateletcrit and other haematological markers, cervical dilatation and effacement, and the neutrophil-to-lymphocyte ratio as an inflammation marker.

MAIN OUTCOME MEASURE

The role of platelet indices in predicting the preterm delivery.

RESULTS

The platelet count, plateletcrit, white blood cell count, red cell distribution width, and neutrophil count were significantly higher in the preterm delivery group. Receiver operating characteristic curve analysis showed that the plateletcrit cut-off value for predicting spontaneous preterm labour was 0.201%, with a sensitivity of 95.6% and specificity of 87.5%; the cut-off value for the platelet count was 234 ? 103/mm3 with a sensitivity of 81.0% and specificity of 71.0%.

CONCLUSION

Plateletcrit is a low-cost, widely available, and noninvasive marker that might be used for the prediction of preterm delivery in patients with a history of preterm labour.

Ingestion of Multiple Magnets for Suicide

Foreign objects ingestion, either intentionally or accidentally, is a well-known problem in paediatric population. However, it is not uncommonly seen in adult especially in patients with psychiatric disorders and prisoners. We presented a case in which a seventeen year-old young man attended emergency department after attempting suicide by cutting his wrist. Incidentally, he was found to have ingested multiple magnets which stayed in the stomach. Removal by endoscopic method was failed. Surgical removal of a total of thirty-three magnets through a surgical gastrostomy was performed. (Hong Kong j.emerg.med. 2015;22: 50-52)