Blue Arrow Research Articles

What is your diagnosis? Peritoneal fluid from a dog.

What is your diagnosis? Peritoneal fluid from a dog.

The Reversed STABILISE Technique

A 64 year old man presented with acute abdominal and chest pain. (A) Computed tomography angiography showed an 84 mm infrarenal aortic aneurysm with retrograde aortic dissection arising from the aneurysm (blue arrow, entry tear) to the middle of the thoracic aorta (red arrows, dissection limits). Owing to persistent abdominal pain, he underwent endovascular aortic repair using an infrarenal bifurcated stent graft (WL Gore, Flagstaff, AZ, USA), followed by bare stenting of the upper abdominal and descending aorta (Cook Medical, Bloomington, IN, USA). Both grafts were expanded as per the STABILISE technique, allowing complete exclusion of the aneurysm and dissection (B).

B-PO05-211 PROGRAMMING CHALLENGES DURING LEFT VENTRICULAR PACING. A CASE OF PACEMAKER-MEDIATED TACHYCARDIA

Multichamber pacing may be associated with complex interactions between pacing timing cycles. Review of a case of pacemaker mediated tachycardia (PMT) during LV pacing. Data was collected by retrospective review. A patient with a history of coronary artery disease and bypass surgery, heart failure and primary prophylaxis dual chamber defibrillator (ICD) underwent upgrade to a biventricular ICD (Boston Scientific Vigilant X4 G247) due to new left bundle branch block and heart failure symptoms. Postoperative programming was identical (DDDR 50/130/130 bpm; PVARP 240-280 ms) except for shortened AV delay with simultaneous RV/LV pacing. During an admission to an outside hospital, AV delay was shortened (SAV: 100 ms, PAV 150 ms) and pacing mode was changed to LV only. In follow-up, numerous PMT episodes were noted in the device memory (Panel A) and also during device interrogation but only with LV-only pacing. Retrograde P wave during LV pacing fell outside the programmed PVARP because retrograde left bundle branch block caused transseptal retrograde conduction via the right bundle branch with delay in LV to RA interval. Timing from RV apex to RA (Panel B, red arrow, 240 ms) was the same during RV pacing and during LV pacing (panel C) but because PVARP is initiated with the first paced ventricular chamber, the V to A time prolonged with LV-only pacing (Panel C, blue arrow, 420 ms) beyond PVARP. Programming very long PVARP limits upper tracking rate so in this case we switched to biventricular pacing which shortened the QRS duration and also eliminated PMT episodes. In CRT devices, PVARP should be reassessed when LV only pacing is programmed.

外科的介入が遅延し，入院後に多発膿瘍を合併した化膿性胸鎖関節炎の1例(Delayed surgical intervention after admission caused whole body multiple abscesses in the patients with septic arthritis of the sternoclavicular joint: a case report)

要旨化膿性胸鎖関節炎は，胸鎖関節周囲の軟部組織に膿瘍形成を来す疾患で，主に整形外科で扱われるが，敗血症性ショックで救命救急センターに搬入される症例は稀である。今回，外科的介入を含めた集学的治療が必要であった化膿性胸鎖関節炎の1例を経験したので報告する。症例は既往歴にコントロール不良の糖尿病がある49歳の男性。1週間前より左鎖骨痛，その2日後に右肩痛が出現し，徐々に痛みの増悪と意識障害を来し，前医にて敗血症性ショックとなり当院へ救急搬送された。CTでは頸部から胸骨にかけて小さな膿瘍形成を認めた。保存的加療で全身状態の改善が得られ，第9病日には一般病棟へ転床した。その後，炎症反応の再燃があり，第16病日の造影CTで，膿瘍は縦隔に進展し，左前腕部，左膝部，両側大腿骨周囲に膿瘍の形成を認めた。抗菌薬投与に加えて胸腔鏡補助下縦隔ドレナージ術および多発膿瘍に対して開窓術を行い，炎症所見は改善し，第69病日にリハビリ目的に転院となった。頸部領域の膿瘍で胸鎖関節周囲が関与している場合は本疾患を鑑別に挙げ，MRIも踏まえた関節炎・骨髄炎の有無について早期に診断を行い，常に外科的介入を念頭に置いたうえで遅延なく的確に行うことが重要である。

Bone marrow mesenchymal stem cells and their derived exosomes resolve doxorubicin-induced chemobrain: critical role of their miRNA cargo

BackgroundDoxorubicin (DOX), a widely used chemotherapeutic agent, can cause neurodegeneration in the brain, which leads to a condition known as chemobrain. In fact, chemobrain is a deteriorating condition which adversely affects the lives of cancer survivors. This study aimed to examine the potential therapeutic effects of bone marrow mesenchymal stem cells (BMSCs) and their derived exosomes (BMSCs-Exo) in DOX-induced chemobrain in rat models.MethodsChemobrain was induced by exposing rats to DOX (2 mg/kg, i.p) once weekly for 4 consecutive weeks. After 48 h of the last DOX dose, a subset of rats was supplied with either an intravenous injection of BMSCs (1 × 106) or a single dose of 150 μg of BMSCs-Exo. Behavioral tests were conducted 7 days post injection. Rats were sacrificed after 14 days from BMSCs or BMSCs-Exo injection.ResultsBMSCs and BMSCs-Exo successfully restored DOX-induced cognitive and behavioral distortion. These actions were mediated via decreasing hippocampal neurodegeneration and neural demyelination through upregulating neural myelination factors (myelin%, Olig2, Opalin expression), neurotropic growth factors (BDNF, FGF-2), synaptic factors (synaptophysin), and fractalkine receptor expression (Cx3cr1). Halting neurodegeneration in DOX-induced chemobrain was achieved through epigenetic induction of key factors in Wnt/β-catenin and hedgehog signaling pathways mediated primarily by the most abundant secreted exosomal miRNAs (miR-21-5p, miR-125b-5p, miR-199a-3p, miR-24-3p, let-7a-5p). Moreover, BMSCs and BMSCs-Exo significantly abrogate the inflammatory state (IL-6, TNF-α), apoptotic state (BAX/Bcl2), astrocyte, and microglia activation (GFAP, IBA-1) in DOX-induced chemobrain with a significant increase in the antioxidant mediators (GSH, GPx, SOD activity).ConclusionsBMSCs and their derived exosomes offer neuroprotection against DOX-induced chemobrain via genetic and epigenetic abrogation of hippocampal neurodegeneration through modulating Wnt/β-catenin and hedgehog signaling pathways and through reducing inflammatory, apoptotic, and oxidative stress state.Graphical abstractProposed mechanisms of the protective effects of bone marrow stem cells (BMSCs) and their exosomes (BMSCs-Exo) in doxorubicin (DOX)-induced chemobrain. Blue arrows: induce. Red arrows: inhibit.

Endophytes: the novel sources for plant terpenoid biosynthesis.

Terpenoids are natural compounds predominantly present in plants. They have many pharmaceutical and/or nutritional functions, and have been widely applied in medical, food, and cosmetics industries. Recently, terpenoids have been used in the clinical treatment of COVID-19 due to the good antiviral activities. The increasing demand for terpenoids in international markets poses a serious threat to many plant species. For environmentally sustainable development, microbial cell factories have been utilized as the promising platform to produce terpenoids. Nevertheless, the bioproduction of most terpenoids cannot meet commercial requirements due to the low cost-benefit ratio until now. The biosynthetic potential of endophytes has gained attention in recent decades owing to the continual discovery of endophytes capable of synthesizing plant bioactive compounds. Accordingly, endophytes could be alternative sources of terpenoid-producing strains or terpenoid synthetic genes. In this review, we summarized the research progress describing the main and supporting roles of endophytes in terpenoid biosynthesis and biotransformation, and discussed the current problems and challenges which may prevent the further exploitation. This review will improve our understanding of endophyte resources for terpenoid production in industry in the future.Graphical abstract The four main research interests on endophytes for terpenoid production. A: Isolation of terpenoid-producing endophytes; B: The heterologous expression of endophyte-derived terpenoid synthetic genes; C: Endophytes promoting their hosts’ terpenoid production. The blue dashed arrows indicate signal transduction; D: Biotransformation of terpenoids by endophytes or their enzymes. Key points • The mechanisms employed by endophytes in terpenoid synthesis in vivo and in vitro.• Endophytes have the commercial potentials in terpenoid bioproduction and biotransformation.• Synthetic biology and multiomics will improve terpenoid bioproduction in engineered cell factories.

Hypertensive emergency: a look into the eye

A 26-year-old man presented to the ophthalmology clinic with sudden painless diminution of vision of both eyes for last 3 days. His corrected visual acuity was 20/200 in right eye...

Relationship between left bundle branch block mechanical patterns and super-response to cardiac resynchronization therapy in patients with congestive heart failure

Abstract Funding Acknowledgements Type of funding sources: None. Background Left bundle branch block (LBBB) assessed by electrocardiography (ECG) is used in current clinical guidelines for patient selection to cardiac resynchronisation therapy (CRT). But percentage of non-responders among patients with congestive heart failure is high. Super-response (SR) to CRT was not enough described in clinical guidelines. We hypothesized that mechanical patterns of LBBB and parameters of mechanical dyssynchrony could be used as predictors of SR to CRT. Aim To assess a relationship of LBBB patterns defined by ECG and echocardiography with SR to CRT. Materials and methods 60 patients (mean age 54.5 ± 10.4 years) were examined at baseline and during follow-up: 10.6 ± 3.6 months. Patients were divided into groups: I group (n = 31) with decrease of left ventricular end-systolic volume (ESV) ≥30% (super-responders) and II group (n = 29) - decrease of LV ESV <30% (non-super-responders). Three strain-markers of LBBB assessed by Tissue Doppler Imaging (TDI) and Speckle Tracking Echocardiography (STE) were used: (1) early contraction of basal or midventricular segment in the septal wall and early stretching of basal or midventricular segment in the lateral wall (yellow arrows); (2) the early peak contraction of the septal wall occurred in the first 70% of the systolic ejection phase (blue arrow); (3) the early stretching wall that showed peak contraction after aortic valve closure (red arrows). The classic LBBB pattern was defined if all three strain-markers were present. The heterogeneous LBBB pattern was defined if two from three strain-markers were present. Results At baseline groups did not differ in main clinical characteristics, including QRS width and LBBB assessed by ECG. Mechanical abnormalities were found only in group I: SF (32.3% vs 0.0%; p = 0.001) and apical rocking (19.4% vs 0.0%; p = 0.024), as well as classic LBBB mechanical pattern (20.8% vs 0.0%; p = 0.05). The complex of heterogeneous LBBB mechanical pattern (HR 7.512; 95% CI 1.434 – 39.632; р=0.025), interventricular mechanical delay (HR 1.037; 95% CI 1.005 – 1.071; р=0.017) and longitudinal strain of interventricular septum mid segment (HR 0.726; 95% CI 0.540 – 0.977; р=0.035) had an independent relationship with SR. According to the ROC analysis the sensitivity and specificity of model in the prediction of SR were 77.3% and 91.3% (AUC = 0.862; p < 0.001). Conclusion SR is associated with both LBBB mechanical patterns assessed by STE and TDI. LBBB defined by ECG did not have significant association with SR to CRT. Abstract Figure.

The Nature and Measures of Osmotic Pressure

Introduction In our first abstract titled “The Concept of Osmotic Pressure: Two Common Misunderstandings and Resolutions” in EB2021, we addressed that osmotic pressure should be defined in the context of a simple osmosis system (i.e., S-m-H2O, with a solution compartment (S) and a water compartment separated by a selectively permeable membrane (m)), not in the context of a composite osmosis system (i.e., S1-m-S2), which can instead be deconstructed into two mirrored simple osmosis systems: S1-m-H2O and H2O-m-S2. In this presentation, we 1) use a new set of terminology to differentiate the osmotic pressure (π) defined in three common ways in physiology and biology as well as in chemistry and physics; 2) address which of these ways represents the nature of π; and 3) illustrate the osmotic pressure difference/gradient in S1-m-S2. Method Logical reasoning as shown in Fig 1 and 2. Results 1) In S-m-H2O (Fig 1a to 1b), osmosis occurs and reaches equilibrium (1). We define the gravitational hydrostatic pressure exerted by the resulting liquid column as πachieved. 2) We define the π applied to S to prevent osmosis as πapplied (Fig 1c). 3) According to van't Hoff's Law, πachieved or πapplied = RTOC0 (OC0 is the initial osmotic concentration in S). 4) In S-m-H2O, a transmembrane pressure drives osmosis (illustrated using the blue arrow in Fig 1c), which can be viewed as exerted by either the water potential difference (Δμ0, not shown) or the OC0 difference (ΔOC0, the red gradient in Fig 1a and 1c) across the m: during osmosis, Δμ0 pushes or ΔOC0 pulls water toward S. We define this pressure to be πTM (TM refers to transmembrane). In physical chemistry, π (our πTM) = const×Δμ01. Hence, πTM = -RTOC0 = const×Δμ0. Conclusion 1) Among the three common ways to define π (πachieved, πapplied, πTM), πTM is thenature ofosmotic pressure; 2) πachieved and πapplied are two different ways to measure πTM. 3) In S1-m-S2, it is the osmotic pressure difference (ΔπTM) that drives osmosis, which can be measured using either Δπachieved or Δπapplied (Fig 2). In our third abstract, titled “The Pressure Profiles of the Equilibrium States of Osmosis Across Plant and Animal Cell Membranes”in EB2021, we will apply the concepts of ΔπTM to analyze the pressure profiles that characterize the equilibrium states of osmosis (after water enters a cell) across plant and animal cell membranes. 1Chang R. Physical Chemistry for the Chemical and Biological Sciences. Sausalito, CA: University Science Books, 2000, p. 235.

Relevance of differential control of sympathorespiratory response magnitudes in clinical assessments.

Relevance of differential control of sympathorespiratory response magnitudes in clinical assessments.

Alignment of linear polymeric grains for highly stable N-type thin-film transistors

Summary Temperature-insensitive properties are attractive for most electronics, including polymeric semiconducting devices. Especially, polymeric field-effect transistors (FETs) with high mobility have been important research targets due to their broad applications. However, polymeric FETs with stable charge transport operating at extremely cold or hot zones are faced with enormous challenges. In this study, the polyacrylonitrile was found to significantly tune the sizes of pre-aggregates of polymers in solutions and the crystallinity of the polymeric films. The orientation of 5–25 μm linear grains in the films were prepared through the bar-coating process with polyacrylonitrile as an additive, which stabilized the electron mobility over a wide range of temperatures. The linear-grain morphology of the film contributed to reducing the holes and grain boundaries in the transport paths of carriers. Typically, the top-gate FETs based on P(NDI2OD-T2) displayed a stable electron transporting behavior from 200 to 460 K, with mobility greater than 3.5 cm2V−1s−1.

Acute visual deterioration and headaches in a patient with suprasellar lesion: Question

•Cavernous malformation should be a differential diagnosis of suprasellar lesions.•Management of asymptomatic optic apparatus cavernous malformation is still debatable.•The relative risk of visual deterioration after repetitive hemorrhage may be higher than the risk of surgical removal. A 62-year-old woman presented with a history of headaches for two weeks and sudden loss of vision in her left eye. Neurological examination revealed right eye acuity 6/6, left eye 6/9.5, left eye relative afferent pupillary defect (RAPD), red desaturation reduced in the same eye, confrontation visual fields showed non-congruent right homonymous hemianopia. Fundoscopy did not show any sign of papilledema or chronic optic atrophy (Fig. 1). There was no other focal neurological deficit [1Tan T. Tee J.W. Trost N. McKelvie P. Wang Y.Y. Anterior visual pathway cavernous malformations.J Clin Neurosci. 2015; 22: 258-267Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar, 2Moriarity J.L. Clatterbuck R.E. Rigamonti D. The natural history of cavernous malformations.Neurosurg Clin N Am. 1999; 10: 411-417Abstract Full Text PDF PubMed Google Scholar, 3Voznyak O. Lytvynenko A. Maydannyk O. Kalenska O. Hryniv N. Cavernous hemangioma of the chiasm and left optic nerve.Cureus. 2020; 12e8068PubMed Google Scholar, 4Hempelmann R.G. Mater E. Schröder F. Schön R. Complete resection of a cavernous haemangioma of the optic nerve, the chiasm, and the optic tract.Acta Neurochir (Wien). 2007; 149: 699-703Crossref PubMed Scopus (30) Google Scholar, 5Mano Y. Kumabe T. Saito R. Watanabe M. Tominaga T. Cavernous malformation of the optic pathway mimicking optic glioma: a case report.Childs Nerv Syst. 2014; 30: 1753-1758Crossref PubMed Scopus (7) Google Scholar, 6Hassler W. Zentner J. Wilhelm H. Cavernous angiomas of the anterior visual pathways.J Clin Neuroophthalmol. 1989; 9: 160-164PubMed Google Scholar, 7Liu J.K. Lu Y. Raslan A.M. Gultekin S.H. Delashaw J.B. Cavernous malformations of the optic pathway and hypothalamus: analysis of 65 cases in the literature.Neurosurg Focus. 2010; 29: E17https://doi.org/10.3171/2010.5.FOCUS10129Crossref PubMed Scopus (48) Google Scholar, 8Crocker M. DeSouza R. King A. Connor S. Thomas N. Cavernous hemangioma of the optic chiasm: a surgical review.Skull Base. 2008; 18: 201-212Crossref PubMed Scopus (21) Google Scholar]. Head computer tomography (CT) with and without contrast revealed a hyperdense non enhanced suprasellar lesion closely related to the left optic chiasma. Brain magnetic resonance imaging (MRI) (Fig. 2) was performed (see Fig. 3).Fig. 3A) Intraoperative image of the left optic tract cavernoma removal (blue arrow) through a left pterional craniotomy, compressing the left optic nerve (red arrow) B) Intraoperative image after removal of the cavernoma, showing the left optic tract (blue star) and the optic chiasm (blue arrow head).View Large Image Figure ViewerDownload Hi-res image Download (PPT) a.Pituitary adenomab.Craniopharyngiomac.Optic nerve gliomad.Optic tract cavernoma Answer on page: 312 The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Acute visual deterioration and headaches in a patient with suprasellar lesion: AnswerJournal of Clinical NeuroscienceVol. 86PreviewD. Optic tract cavernoma Full-Text PDF

Acute visual deterioration and headaches in a patient with suprasellar lesion: Answer

•Cavernous malformation should be a differential diagnosis of suprasellar lesions.•Management of asymptomatic optic apparatus cavernous malformation is still debatable.•The relative risk of visual deterioration after repetitive hemorrhage may be higher than the risk of surgical removal. D. Optic tract cavernoma The patient underwent surgery through a left pterional craniotomy, and the intraoperative findings revealed a cavernoma in the left optic chiasm extending forward into the left optic nerve and posteriorly to the optic tract. (Fig. 3). Cavernous malformation (CM) is a common intracranial vascular lesion and accounts for 10 – 15% [1Tan T. Tee J.W. Trost N. McKelvie P. Wang Y.Y. Anterior visual pathway cavernous malformations.J Clin Neurosci. 2015; 22: 258-267Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar, 2Moriarity J.L. Clatterbuck R.E. Rigamonti D. The natural history of cavernous malformations.Neurosurg Clin N Am. 1999; 10: 411-417Abstract Full Text PDF PubMed Google Scholar] of the cases. The most common location is supratentorial (80%), brainstem (15%), and spinal cord (5%). Optic nerve CMs are very rare, with only 70 cases reported in the literature [3Voznyak O. Lytvynenko A. Maydannyk O. Kalenska O. Hryniv N. Cavernous Hemangioma of the Chiasm and Left Optic Nerve.Cureus. 2020; 12e8068PubMed Google Scholar, 4Hempelmann R.G. Mater E. Schröder F. Schön R. Complete resection of a cavernous haemangioma of the optic nerve, the chiasm, and the optic tract.Acta Neurochir (Wien). 2007; 149: 699-703Crossref PubMed Scopus (30) Google Scholar, 5Mano Y. Kumabe T. Saito R. Watanabe M. Tominaga T. Cavernous malformation of the optic pathway mimicking optic glioma: a case report.Childs Nerv Syst. 2014; 30: 1753-1758Crossref PubMed Scopus (7) Google Scholar, 6Hassler W. Zentner J. Wilhelm H. Cavernous angiomas of the anterior visual pathways.J Clin Neuroophthalmol. 1989; 9: 160-164PubMed Google Scholar]. The relative risk of hemorrhage from asymptomatic supratentorial cavernomas is 0.7 to 3.1% per year [[7]Liu J.K. Lu Y. Raslan A.M. Gultekin S.H. Delashaw J.B. Cavernous malformations of the optic pathway and hypothalamus: analysis of 65 cases in the literature.Neurosurg Focus. 2010; 29: E17https://doi.org/10.3171/2010.5.FOCUS10129Crossref PubMed Scopus (45) Google Scholar] Management of asymptomatic CM within the optic apparatus is problematic and requires consideration of the relative risk of hemorrhage with devastating visual loss consequences against those of surgery. In contrast, the risk increases in patients with previous hemorrhages up to 3.8% to 22.9% [[7]Liu J.K. Lu Y. Raslan A.M. Gultekin S.H. Delashaw J.B. Cavernous malformations of the optic pathway and hypothalamus: analysis of 65 cases in the literature.Neurosurg Focus. 2010; 29: E17https://doi.org/10.3171/2010.5.FOCUS10129Crossref PubMed Scopus (45) Google Scholar]. Since a small hemorrhage from a cavernoma located in the anterior optic apparatus could have catastrophic consequences, we recommend resection of the lesion in cases with radiological or clinical evidence of hemorrhage [[8]Crocker M. DeSouza R. King A. Connor S. Thomas N. Cavernous hemangioma of the optic chiasm: a surgical review.Skull Base. 2008; 18: 201-212Crossref PubMed Scopus (20) Google Scholar], as subsequent hemorrhage risk with visual loss is increased (Fig. 1, Fig. 2).Fig. 2A) Axial T1-weighted gadolinium-enhanced MRI, and B) axial T2-weighted MRI showing a left side non-enhancing hypointense suprasellar lesion, in a 62-year-old woman.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Fig. 3A) Intraoperative image of the left optic tract cavernoma removal (blue arrow) through a left pterional craniotomy, compressing the left optic nerve (red arrow) B) Intraoperative image after removal of the cavernoma, showing the left optic tract (blue star) and the optic chiasm (blue arrow head).View Large Image Figure ViewerDownload Hi-res image Download (PPT) The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Acute visual deterioration and headaches in a patient with suprasellar lesion: QuestionJournal of Clinical NeuroscienceVol. 86PreviewA 62-year-old woman presented with a history of headaches for two weeks and sudden loss of vision in her left eye. Neurological examination revealed right eye acuity 6/6, left eye 6/9.5, left eye relative afferent pupillary defect (RAPD), red desaturation reduced in the same eye, confrontation visual fields showed non-congruent right homonymous hemianopia. Fundoscopy did not show any sign of papilledema or chronic optic atrophy (Fig. 1). There was no other focal neurological deficit [1–8]. Full-Text PDF

Abdominal Positron Emission Tomography Combined With Magnetic Resonance Imaging in Chronic Granulomatous Disease

Abdominal Positron Emission Tomography Combined With Magnetic Resonance Imaging in Chronic Granulomatous Disease

Fascial Plane Blocks: More Questions Than Answers?

Fascial Plane Blocks: More Questions Than Answers?

Synergistic Combination of Calcium and Citrate in Mesoporous Nanoparticles Targets Pleural Tumors

Summary Conventional chemotherapy leads to severe adverse effects since it involves systemic administration of toxic drugs at high dosage. Unlike traditional chemotherapeutics, calcium phosphate and citrate have both been discussed as very promising anticancer agents and are not inherently toxic. Yet, their breakthrough has been hampered by the lack of an administration approach that overcomes the strict regulatory mechanisms of the cell. Here, we present a combinatorial administration of calcium, phosphate, and citrate as colloidal, amorphous nanoparticles (CPCs) that selectively kill cancer cells without involvement of inherently toxic drugs. The particles are toxic neither before endosomal release nor after their degradation. This highly selective toxicity allowed us to successfully treat two different aggressive pleural tumors in mice, reducing their size by about 40% and 70% after only two local applications. Safety assessment studies over 2 months show no signs of adverse effects except for slightly enhanced pleural thickening after eight applications.

Ineffective trigger, the always missed sign

Yellow curve: Pressure (cmH2O) on X-axis and Time (seconds) on Y-axis Pink curve: Flow (L/sec) on X-axis and Time (seconds) on Y-axis Green curve: Tidal volume (ml) on X-axis and Time (seconds) on Y-axis Orange curve: Esophageal pressure (cmH2O) on X-axis and Time (seconds) on Y-axis The blue arrows point to the inspiratory effort on flow and esophageal curves that is not followed by a breath

Superior Mesenteric Arteriovenous Fistula

Arteriovenous fistulae between the superior mesenteric artery (SMA) and superior mesenteric vein (SMV) are extremely rare; most are associated with abdominal trauma. A 47 year old woman who was diagnosed with extensive metastatic ovarian carcinoma presented with right sided low abdominal pain. She denied any history of abdominal surgery. Plain computed tomography (CT) showed bowel oedema. Intestinal vasculopathy was suspected. Contrast enhanced CT angiography revealed not only a hyperaemic bowel (white arrow), but also a fistula between the SMA (red arrow) and SMV (blue arrow; A and B). Endovascular fistula exclusion was recommended, but the patient declined further treatment.Image 1

B and Ga Co-Doping in Epitaxial SiGe: Challenges and Opportunities

Contact resistances are inherent to any device connected to the outside world. Lowering their contribution is essential for high-performance applications. This is the case for advanced Si CMOS technologies, for which series resistance parasitics become the main performance detractor from the 14 nm node onwards [1-2]. For p-type fin and gate-all-around field effect transistors, focus is placed on Ti contacts to p-Si1-xGex source/drain (S/D) [3].Several non-equilibrium doping techniques have been explored to enhance active doping in S/D regions and decrease contact resistivities (ρc) down to ≤ 1x10-9 Ω.cm2. In most cases, low temperature doping processes are used to favor the incorporation of dopants and their activation [4]. Alternative dopants, with higher solid solubilities and advantageous segregation behaviors favoring the formation of dopant-enriched films at the metal-semiconductor interface, are also evaluated. Very low ρc values have e.g. been reported by combining Ga ion implantation in Si0.4Ge0.6 and ns laser annealing [5]; whereas in situ doping was optimized in Si1-xGex:B [6-9] and Si0.5Ge0.5:B:Ga, grown by chemical vapor deposition using metalorganic (MO) Ga precursors [4,10]. In this contribution, we highlight opportunities and challenges offered by this approach.The maximum solubility of Ga in Ge is more than 100x higher than that of B [11-12]. However, controlling the incorporation and distribution of Ga dopants in Si0.5Ge0.5(:B) is not straightforward. This relates to the tendency for Ga to segregate towards the surface, as reported in [4,10] and shown in Fig. 1(a). We rely on Si0.5Ge0.5:B:Ga co-doped epi layers in which bulk resistivity is lowered thanks to high B-doping concentrations, while contact resistivity minimization is expected from Ga segregation towards the contact region. It appears, however, that Ga surface doping concentrations significantly higher than 3E20 cm-3 are required to efficiently reduce ρc [5,13]. Targeting such high surface concentrations comes with the risk of Ga agglomeration into Ga-rich defects on S/D surfaces. Another detractor lies in the possible consumption of superficial Ga during native oxide removal preceding contact processing. Results presented in Fig. 1(b) suggest such a ~ 10x decrease in Ga concentration close to the S/D surface after native oxide removal. Systematic investigations are underway to clarify this aspect, which could lead us to reconsider our contacting scheme.Activating high levels of Ga dopants in in situ doped epi layers is an additional challenge. Preliminary results indicate that, in the conditions explored in this work, only a small fraction of the dopants incorporated in SiGe:Ga are active. This limitation may be attributed to Ga dopants clustering or to interactions with unwanted C incorporated during growth. Fig. 1(c) illustrates our effort in reducing C incorporation in SiGe:B:Ga by utilizing 2 different Ga MO precursors, namely MO1 and MO2, while keeping all other growth parameters the same. For this test, an undoped SiGe cap was used to separate contributions from adventitious C and C really incorporated in the SiGe:B:Ga layer. Ga profiles appear to be affected by the capping, with part of the Ga dopants migrating towards the top part of the stack. C impurities are on the other hand assumed to be frozen in their original position [14]. While the level of incorporated C is not significantly affected by the choice of precursor, a shorter Ga incorporation delay, materialized by blue arrows in Fig. 1(c), and a larger [Ga] / [C] ratio are extracted from the layer grown with MO2.

Ternary Pt Alloy Catalysts and Carbon Modified Supports for Low Pt Loaded Fuel Cell Cathodes

The sluggish kinetics of the oxygen reduction reaction (ORR) at the cathode of proton exchange membrane fuel cells (PEMFCs) and the harsh environment pose challenges on the development of cheap, active and stable catalysts. As a consequence, Pt catalysts are the most utilized catalysts in commercial PEMFC stacks for automotive applications. While the progress in the recent years allowed a considerable decrease of Pt loadings (from 0.4-0.8 to ~0.1 mgPt cm-2), other challenges emerged at such and lower Pt loadings at high current densities.1 For example, octahedral PtNi nanoparticles have been reported to achieve extremely high mass activity in rotating disk electrode (RDE) experiments2 and the introduction of a third metal as surface dopant has been shown to have beneficial effects on the RDE performance.3 Despite these promising steps toward shape-stable PtNiX octahedral nanoparticles, the morphological stability and the performance in membrane electrode assembly (MEA)-based fuel cell measurements still need to be improved to match and surpass the state of the art Pt and dealloyed Pt-alloy catalysts.4 In this contribution we will show our recent efforts in improving the performance of PtNi based octahedral nanoparticle catalysts towards integration in low Pt loading cathodes for PEMFC. In particular, two strategies will be presented. First, Rh surface doping is introduced to improve the morphological stability. Second, new carbon modified supports by nitrogen plasma treatment have been investigated. References A. Kongkanand and M. F. Mathias, J Phys Chem Lett, 2016, 7, 1127-1137.P. Strasser, Science, 2015, 349, 379-380.X. Q. Huang, Z. P. Zhao, L. Cao, Y. Chen, E. B. Zhu, Z. Y. Lin, M. F. Li, A. M. Yan, A. Zettl, Y. M. Wang, X. F. Duan, T. Mueller and Y. Huang, Science, 2015, 348, 1230-1234.F. Dionigi, C. C. Weber, M. Primbs, M. Gocyla, A. M. Bonastre, C. Spöri, H. Schmies, E. Hornberger, S. Kühl, J. Drnec, M. Heggen, J. Sharman, R. E. Dunin-Borkowski and P. Strasser, Nano Lett, 2019, 19, 6876-6885. Acknowledgements The GAIA project has received funding from the Fuel Cells and Hydrogen 2 Joint Undertaking under grant agreement No 826097. This Joint Undertaking receives support from the European Union’s Horizon 2020 research and innovation programme, Hydrogen Europe and Hydrogen Europe Research. Figure 1. Mass activity from RDE measurements as a function of the electrochemically active surface area obtained by hydrogen under potential deposition, before (black) and after (red) stability tests. The blue arrow and the percentage indicate the loss after stability tests. Pt/Cv and Oh-PtNiMo/Cv data from ref.4. Figure 1