On the Anomalies in Gold Nanoparticles Prepared by Micelle Nanolithography and Their Impact on One-Dimensional Material Synthesis : Role of Substrate, Size Effects and Impurity

Die Synthese von eindimensionalen (1-D) anorganischen Halbleitern, wie Nanoröhrchen und Silizium (Si) Nanodrähten, erfolgt normalerweise durch katalytische Prozesse aus Nanopartikeln. Obwohl diese Technik der Synthese wohl bekannt ist, sind zum Beispiel noch Fragen bezüglich der Tieftemperatursynthese oder der Kontrolle über die Größe der Katalysepartikel welche den Durchmesser der 1-D Strukturen bestimmen offen. Zusätzlich ist die Umsetzung der Technologie von teueren kristallinen auf billige, etwa gläserne Substrate wünschenswert. Diese Arbeit verwendet die bereits etablierte Herstellung, über Selbstorganisation, von regelmäßig angeordneten Goldnanopartikeln mit definierter Größe auf Substraten. Dies ermöglichte es, Si 1-D Strukturen mit einem definierten Durchmesser von weniger als 20 nm zu produzieren. Tieftemperatursynthese war möglich durch die erhöhte Katalyseaktivität der Goldpartikel, nachdem sie gezielt mit Defekten in verschiedenen Plasmaumgebungen angereichert wurden. Dadurch wuchsen Si 1-D Strukturen aus Si,SiOx/Si und Borosilikatglas-Substraten bei bereits 320°C. Spannungen, welche durch das Substrat induziert werden, beeinflussen die Si-Diffusíon an den Goldnanopartikeln und bestimmen dadurch ob Nanoröhren oder Nanodrähte wachsen. Die gewonnenen Ergebnisse sind auch von technologischer Relevanz, da die Tieftemperatursynthese eine ökonomischere Herstellung erlaubt und die Kontrolle über den Durchmesser der Strukturen die Funktionsvielfalt erhöht. Zusätzlich kann man durch die Wahl der Substrat induzierten Spannungen und ihren Einfluss auf die Si-Diffusion die Art der Si 1-D Strukturen gezielt einstellen

Debranching abdominal aortic hybrid surgery for aortic diseases involving the visceral arteries

ObjectiveAortic diseases involving branches of the visceral arteries mainly include thoracoabdominal aortic aneurysm (TAAA), aortic dissection (AD) and abdominal aortic aneurysm (AAA). The focus of treatment is to reconstruct the splanchnic arteries and restore blood supply to the organs. Commonly used methods include thoracoabdominal aortic replacement, thoracic endovascular aortic repair and hybrid approaches. Hybrid surgery for aortic disease involving the visceral arteries, consisting of visceral aortic debranching with retrograde revascularization of the celiac trunk and renal arteries and using stent grafts, has been previously described and may be considered particularly appealing in high-risk patients. This study retrospectively analyzed recorded data of patients and contrasted the outcomes with those of a similar group of patients who underwent conventional open repair surgery.MethodsBetween 2019 and 2022, 72 patients (52 men) with an average age of 61.57 ± 8.66 years (range, 36–79 years) underwent one-stage debranching abdominal aortic hybrid surgery. These patients, the hybrid group, underwent preoperative Computed Tomographic Angiography (CTA) and had been diagnosed with aortic disease (aneurysm or dissection) involving the visceral arteries and were at high risk for open repair. The criteria used to define these patients as high-risk group who are in the need of hybrid treatment were American Society of Anesthesiologists (ASA) class 3 or 4. In all cases, we accomplished total visceral aortic debranching through a previous visceral artery retrograde revascularization with synthetic grafts (customized Y or four-bifurcated grafts), and aortic endovascular repair with one of two different commercially produced stent grafts (Medtronic® and Lifetech®). In some cases, we chose to connect the renal artery to the artificial vessel with a stent graft (Viabahn) and partly or totally anastomosed. We analyzed the results and compared the outcomes of the hybrid group with those of a similar group of 46 patients (36 men) with an average age 54.15 ± 12.12 years (range, 32–76). These 46 patients, the conventional open group, were selected for having had thoracoabdominal aortic replacement between 2019 and 2022.ResultsIn the hybrid group, 72 visceral bypasses were completed, and endovascular repair was successful in all cases. No intraoperative deaths occurred. Perioperative mortality was 2.78%, and perioperative morbidity was 9.72% (renal insufficiency in 1, unilateral renal infarction in 5, Intestinal ischemia in 1). At 1-month postoperative CTA showed 2 endoleaks, one of which was intervened. At follow-up, there were unplanned reoperation rate of 4.29% and 5 (7.14%) deaths. The remaining patients’ grafts were patent at postoperative CTA and no endoleak or stent graft migration had occurred. In the conventional open group, 1 died intraoperatively, 4 died perioperatively, perioperative mortality was 10.87% and complications were respiratory failure in 5, intestinal paralysis/necrosis in 4, renal insufficiency in 17, and paraplegia in 2. At follow-up, 5 (12.20%) patients presented with synthetic grafts hematoma 4 (9.76%) patient died, and 6 (14.63%) patients required unplanned reoperation intervention.ConclusionHybrid surgery is technically feasible in selected cases. For aortic diseases involving the visceral arteries, the application of hybrid abdominal aorta debranching can simplify the operation process, decrease the risks of mortality and morbidity in high-risk and high-age populations and decrease the incidence of various complications while achieving ideal early clinical efficacy. However, a larger series is required for valid statistical comparisons, and longer follow-ups are necessary to evaluate the long-term efficacy of hybrid surgery

Future prospects of internet banking

The research titled the Prospects of Internet Banking was carried out in Kimbo Police Cooperative Credit Union (KIPCCUL), North West region Cameroon. The research was carried out based on the observation that in most financial institutions in Cameroon internet banking is still at the introductory level and this is a high innovation that has taken place in the banking sector and many people do not want to embrace this new development. The aim of this research work was to find out what the future holds for internet banking in Cameroon, some of the problems faced in carrying out this activity, the benefits, the risk involved and above all some proposed solutions to make internet banking usage smooth and convenient now and in the future. A questionnaire was used to collect information, while secondary data was used to collect information from the internet, books found in the library and from some documents from the responses of the questionnaire issued. Based on the findings, it shows that internet banking in microfinance institutions is necessary. It is worth mentioning that the aim of internet banking is to reduce the workload and make banking more convenient and efficient as well as maximizing profit as a result banks have to put in more efforts in educating their customers about the importance of this internet banking and try to make it worthwhile

Selective growth of organic 1-D structures on Au nanoparticle arrays

We demonstrate that the growth of F16CuPc 1-D nanostructures can be directed by templates of gold nanoparticles. The growth occurs via vapor-phase transport, whereby the gold nanoparticles act as nucleation sites for F16CuPc molecules and promote their anisotropic growth. The F16CuPc 1-D structures adopt diameters of approximately 15-30 nm independent of the nanoparticle size. This approach enables a technologically simple and inexpensive fabrication of very uniform organic 1-D structures (aspect ratio of approximately 30) and precise control of their location and packing density

Low-temperature growth of silicon nanotubes and nanowires on amorphous substrates

Silicon one-dimensional (Si 1D) materials are of particular relevance due to their prospect as versatile building materials for nanoelectronic devices. We report the growth of Si 1D structures from quasi-hexagonally ordered gold (Au) nanoparticle (NP) arrays on borosilicate glass (BSG) and SiOx/Si substrates. Using hydrogen instead of oxygen plasma during NP preparation enhances the catalytic activity of AuNPs (diameters of 10−20 nm), enabling Si 1D growth at temperatures as low as 320 °C. On BSG, Si nanowires (SiNWs) are identified and reasonable vertical alignment is achieved at 420 °C. On SiOx/Si, only Si nanotubes (SiNTs) are obtained right up to 420 °C. A mixture of SiNTs and SiNWs is observed at 450 °C and only SiNWs grow at 480 °C

Self-assembly of phthalocyanine nanotubes by vapor-phase transport

Gold-borne: Phthalocyanine (F16CuPc) assembles into multiwalled nanotubes by vapor deposition onto SiO2 surfaces functionalized by Au nanodots. Their length can be tuned over a large range. The picture shows the wall spacing d* of a F16CuPc nanotube as deduced from the first diffraction fringe of the electron diffractogram

Chemical seeded growth of Ag nanoparticle arrays and their application as reproducible SERS substrates

This communication refers to the design of a novel, highly efficient and uniform substrate for SERS. The method takes advantage of the block copolymer micelle nanolithography concept for making well-ordered and uniformly spaced gold nanodot assemblies, which are subsequently used as seed substrates for chemical growth, thereby yielding Ag nanoparticle arrays containing a high density of hot spots, which render these concentrated island films ideal substrates for reproducible surface enhanced Raman scattering (SERS) detection