Small Cavity Research Articles

Low-noise microwave generation with an air-gap optical reference cavity

We demonstrate a high finesse, microfabricated mirror-based, air-gap cavity with volume less than 1 ml, constructed in an array, that can support low-noise microwave generation through optical frequency division. We use the air-gap cavity in conjunction with a 10 nm bandwidth mode-locked laser to generate low phase noise 10 GHz microwaves, exhibiting a phase noise of −95 and −142 dBc/Hz at 100 Hz and 10 kHz offset frequencies, respectively. This is accomplished using the 2-point lock optical frequency division method, where we exploit 40 dB common-mode rejection of two lasers separated by 1.29 THz and locked to the same air-gap cavity. If used with an octave spanning comb, the air-gap cavity is capable of supporting 10 GHz phase noise below −160 dBc/Hz at 10 kHz offset, a level significantly lower than electronic synthesizers. These results show how extremely small optical reference cavities, operated without the benefit of vacuum enclosures or thermal insulation, can, nonetheless, support state-of-the-art microwave phase noise in compact and portable systems.

Quantitative evaluation of middle ear radiopacity in French bulldogs using X-ray imaging.

Radiographic examination of the middle ear in French bulldogs can be challenging due to their small ear cavity and thick walls. Quantifying opacity on radiographic images is required to determine normal or abnormal results. To quantify the radiographic opacity of the middle ear in French bulldogs and create a threshold for objective diagnosis. A study was conducted on 32 French Bulldogs using radiographic images. Significant difference tests were performed on the ears of patients with unilateral and bilateral middle ear filling on computed tomography. A threshold was established for detecting left-right asymmetry in the same individuals. In addition, comparisons were made between the filling and nonfilling middle ear groups to establish a threshold of pixel values that could determine single middle ear filling and nonfilling for different patient images. Significant differences were observed in the left-right difference in max, left-right difference in max-ave, and left-right ratio of max-ave between unilateral and bilateral filling groups. The max-ave left-right ratio had the highest area under the curve value with a cutoff of 1.077% and 92.3% sensitivity. The item that showed a significant difference between middle ear groups with and without filling was corrected for nasopharyngeal pixel values with a cutoff of 1.028% and 85% sensitivity. Pixel value ratios in the middle ear region can detect asymmetries in ear densities. The max value in the region compared to the same image's nasopharyngeal region can determine the filling. Combining individual ear evaluations and symmetry improves accuracy.

A Novel Method to Design Small Wideband Half Mode Cavity Antenna Under Resonances of TM₁,₁ and TM₃,₁ Modes

A Novel Method to Design Small Wideband Half Mode Cavity Antenna Under Resonances of TM₁,₁ and TM₃,₁ Modes

Diode-pumped high-power gigahertz Kerr-lens mode-locked solid-state oscillator enabled by a dual-confocal ring cavity

Abstract Femtosecond oscillators with gigahertz (GHz) repetition rate are appealing sources for spectroscopic applications benefiting from the individually accessible and high-power comb line. The mode mismatch between the potent pump laser diode (LD) and the incredibly small laser cavity, however, limits the average output power of existing GHz Kerr-lens mode-locked (KLM) oscillators to tens of milliwatts. Here, we present a novel method that solves the difficulty and permits high average power LD-pumped KLM oscillators at GHz repetition rate. We propose a numerical simulation method to guide the realization of Kerr-lens mode-locking and comprehend the dynamics of the Kerr-lens mode-locking process. As a proof-of-principle demonstration, an LD-pumped Yb:KGW oscillator with up to 6.17-W average power and 184-fs pulse duration at 1.6-GHz repetition rate is conducted. The simulation had a good agreement with the experimental results. The cost-effective, compact and powerful laser source opens up new possibilities for research and industrial applications.

Construction of polypyrrole nanoparticles with a rough surface for enhanced chemo-photothermal therapy against triple negative breast cancer.

Triple-negative breast cancer (TNBC) is the most malignant subtype of breast cancer, characterized by aggressive malignancy and a poor prognosis. Emerging nanomedicine-based combination therapy represents one of the most promising strategies for combating TNBC. Polypyrrole nanoparticles (PPY) are excellent drug delivery vehicles with outstanding photothermal performances. However, the impact of morphology on PPY's drug loading efficiency and photothermal properties remains largely unexplored. In this study, we propose that pluronic P123 can assist in the synthesis of polypyrrole nanoparticles with rough surfaces (rPPY). During the synthesis, P123 formed small micelles around the nanoparticle surface, which were later removed, resulting in small pits and cavities in rPPY. Subsequently, the rPPY was loaded with the chemotherapy drug gemcitabine (Gem@rPPY) for chemo-photothermal therapy against TNBCs. Our results demonstrate that rPPY exhibited superior photothermal performance and significantly enhanced drug loading efficiency by five times compared to smooth PPY nanoparticles. In vitro assessments confirmed Gem@rPPY's robust photothermal properties by efficiently converting light into heat. Cell culture experiments with 4T1 cells and a TNBC mice model revealed significant tumor suppression upon Gem@rPPY administration, emphasizing its efficacy in inducing apoptosis. Toxicity evaluations demonstrated minimal adverse effects both in vitro and in vivo, highlighting the biocompatibility of Gem@rPPY. Overall, this study introduces a promising combination therapy nanoplatform that underscores the importance of surface engineering to enhance therapeutic outcomes and overcome current limitations in TNBC therapy.

ВИНАХІД КОМП‘ЮТЕРНОЇ ТОМОГРАФІЇ І ЙОГО ЗНАЧЕННЯ В ІСТОРІЇ ПУЛЬМОНОЛОГІЇ

Imaging diagnostic methods in pulmonology originate from the discovery of X-rays. Radiography is the first-line tool for chest imaging, but in many cases its capabilities are limited. The aim was to study the history of the invention of computed tomography. Since the radiogram is a two-dimensional summation image of a three-dimensional anatomical structure, there was a need to visualize separate layers of the pathological process. Since 1913, many technical solutions of tomography have been tested. Linear tomography for some time served for the diagnosis of lung pathology, helped to determine the localization more accurately, examine a prevalence, nature and structure of the pathological process, to detect small pathological formations and cavities. But the quality of tomography was not satisfactory. The two outstanding inventors of computed tomography who were awarded the 1979 Nobel Prize in Medicine were not the physicians. Allan McLeod Cormack (Professor and Head of the Institute of Physics at Tufts University, Medford, Massachusetts, USA) was the first to outline the principles of cross-sectional tissue reconstruction in an organ based on X-ray projections in 1963. Godfrey Newbold Hounsfield (Head of Medical Research at Electric and Musical Industries, Middlesex, England) not only reproduced the mathematical algorithms of the technique, but also designed the tomograph and directly participated in its clinical implementation in 1971. Among the developers of the idea of three-dimensional X-ray tomography in 19571958 were the scientists of Kyiv Polytechnic Institute Semyon Tetelbaum and Boris Korenblyum. Key words: radiology, computed tomography, history of pulmonology.

Rapid Evaporation of a Metal Electrode for a High-Efficiency Perovskite Solar Cell.

Organic-inorganic hybrid perovskite solar cells (PSCs) have attracted considerable attention due to the excellent optoelectronic properties of perovskite materials. The energy consumption and high cost issues of metal electrode evaporation should be addressed before large-scale manufacturing and application. We developed an effective metal electrode evaporation procedure for the fabrication of high-efficiency planar heterojunction (PHJ) PSCs, with an inverted device structure of glass/indium tin oxide (ITO)/poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA)/perovskite/[6,6]-phenyl-C61-butyric acid methyl ester (PCBM)/(E)-β-caryophyllene (BCP)/Ag. The effect of the evaporation rate for an evaporator with a small-volume metal cavity on the performance of PHJ-PSC devices was investigated systematically. Through controlling the processes of Ag electrode evaporation, the charge dynamics of the devices were studied by analyzing their charge recombination resistance and lifetime, as well as their defect state density. Our findings reveal that the evaporation rate of an evaporator with a small cavity is favorable for the performance of PHJ-PSCs. As a result, PHJ-PSCs fabricated using a very thin, non-doped PTAA film exhibit photoelectric conversion efficiency (PCE) of 19.21%, with an open-circuit voltage (Voc) of 1.132 V. This work showcases the great potential of rapidly evaporating metal electrodes to reduce fabrication costs, which can help to improve the competitiveness in the process of industrialization.

Spondylocostal dysostosis: A rare case report

Spondylocostal dysostosis (SCD), also known as Jarcho Levin syndrome, is a rare congenital dysostosis characterized by multiple congenital vertebral and rib anomalies. The child usually presents with respiratory distress at birth with eventual development of short trunk dwarfism. Associated congenital anomalies are rare; however, they need evaluation. We report a 6-month-old Indian girl with SCD who presented with respiratory distress and an asymmetrical small thoracic cavity. The diagnosis was made with radiographs, computed tomography scans, and magnetic resonance imaging (MRI) showing multiple rib and vertebral segmentation anomalies. We would also highlight the importance of MRI in these patients and illustrate other associated brain and spine anomalies.

Pleural macrophages translocate to the lung during infection to promote improved influenza outcomes.

Seasonal influenza results in 3 to 5 million cases of severe disease and 250,000 to 500,000 deaths annually. Macrophages have been implicated in both the resolution and progression of the disease, but the drivers of these outcomes are poorly understood. We probed mouse lung transcriptomic datasets using the Digital Cell Quantifier algorithm to predict immune cell subsets that correlated with mild or severe influenza A virus (IAV) infection outcomes. We identified a unique lung macrophage population that transcriptionally resembled small serosal cavity macrophages and whose presence correlated with mild disease. Until now, the study of serosal macrophage translocation in the context of viral infections has been neglected. Here, we show that pleural macrophages (PMs) migrate from the pleural cavity to the lung after infection with IAV. We found that the depletion of PMs increased morbidity and pulmonary inflammation. There were increased proinflammatory cytokines in the pleural cavity and an influx of neutrophils within the lung. Our results show that PMs are recruited to the lung during IAV infection and contribute to recovery from influenza. This study expands our knowledge of PM plasticity and identifies a source of lung macrophages independent of monocyte recruitment and local proliferation.

Boosting Thermoelectric Performance of Bi2 Te3 Material by Microstructure Engineering.

Due to the intrinsic contradiction of electrical conductivity and Seebeck coefficient in thermoelectric materials, the enhancement for the power factor (PF) is limited. Since the PF decides the output power, strategies to the enhancement of PF are of paramount importance. In this work, Bi2 Te3 /Sb and Bi2 Te3 /W multilayer films are proposed to enhance the thermoelectric properties. Both systems possess extremely high conductivity of ≈5.6 × 105 Sm-1 . Moreover, the electrical conductivity and Seebeck coefficient simultaneously increase as temperature rising, showing the overcome of the intrinsic contradiction. This results in ultrahigh PFs of 1785 µWm-1 K-2 for Bi2 Te3 /W and of 1566 µWm-1 K-2 for Bi2 Te3 /Sb at 600 K. Thermal heating of the Bi2 Te3 /Sb multilayer system shows compositional changes with subsequent formation of Bi-Te-Sb phases, Sb-rich Bi-Te precipitates, and cavities. Contrary, the multilayer structure of the Bi2 Te3 /W films is maintained, while Bi2 Te3 grains of high-crystalline quality are confined between the W layers. In addition, bilayer defects in Bi2 Te3 and smaller cavities at the interface to W layers are also observed. Thus, compositional and confinement effects as well as structural defects result in the ultrahigh PF. Overall, this work demonstrates the strategies on how to obtain ultrahigh PFs of commercial Bi2 Te3 material by microstructure engineering using multilayer structures.

Mg(C3 O4 H2 )(H2 O)2 : A New Ultraviolet Nonlinear Optical Material Derived from KBe2 BO3 F2 with High Performance and Excellent Water-Resistance.

Acquiring high-performance ultraviolet (UV) nonlinear optical (NLO) materials that simultaneously exhibit a strong second harmonic generation (SHG) coefficients, as short as possible SHG phase-matching (PM) wavelength and non-hygroscopic properties has consistently posed a significant challenge. Herein, through multicomponent modification of KBe2 BO3 F2 (KBBF), an excellent UV NLO crystal, Mg(C3 O4 H2 )(H2 O)2 , was successfully synthesized in malonic system. This material possesses a unique 2D NLO-favorable electroneutral [Mg(C3 O4 H2 )3 (H2 O)2 ]∞ layer, resulting in the rare coexistence of a strong SHG response of 3×KDP (@1064 nm) and short PM wavelength of 200 nm. More importantly, it exhibits exceptional water resistance, which is rare among ionic organic NLO crystals. Theoretical calculations revealed that its excellent water-resistant may be originated from its small available cavity volumes, which is similar to the famous LiB3 O5 (LBO). Therefore, excellent NLO properties and stability against air and moisture indicate it should be a promising UV NLO crystal.

Mg(C3O4H2)(H2O)2: A New Ultraviolet Nonlinear Optical Material Derived from KBe2BO3F2 with High Performance and Excellent Water‐Resistance

AbstractAcquiring high‐performance ultraviolet (UV) nonlinear optical (NLO) materials that simultaneously exhibit a strong second harmonic generation (SHG) coefficients, as short as possible SHG phase‐matching (PM) wavelength and non‐hygroscopic properties has consistently posed a significant challenge. Herein, through multicomponent modification of KBe2BO3F2 (KBBF), an excellent UV NLO crystal, Mg(C3O4H2)(H2O)2, was successfully synthesized in malonic system. This material possesses a unique 2D NLO‐favorable electroneutral [Mg(C3O4H2)3(H2O)2]∞ layer, resulting in the rare coexistence of a strong SHG response of 3×KDP (@1064 nm) and short PM wavelength of 200 nm. More importantly, it exhibits exceptional water resistance, which is rare among ionic organic NLO crystals. Theoretical calculations revealed that its excellent water‐resistant may be originated from its small available cavity volumes, which is similar to the famous LiB3O5 (LBO). Therefore, excellent NLO properties and stability against air and moisture indicate it should be a promising UV NLO crystal.

Chemotherapy with inclusion of doxorubicin, ifosfamide for common malignant glomus tumor of soft tissues of forearm (clinical case and literature review)

Malignant glomus tumor is an extremely rare, aggressive neoplasm, which is contain from modified glomus body’s cells. The correct morphological diagnosis is difficult, and requires careful differential diagnosis between neuroendocrine tumors, pericytic tumors, smooth muscle neoplasms. The literature describes only sporadic clinical observations, a series of cases and the results of a small number of retrospective studies. Due to the rarity of nosology, the optimal treatment strategy for this disease has not been developed. Most cases, surgical treatment is used in a locally common process. Cases of metastasis of a malignant glomus tumor are extremely rare. There is no consensus on the tactics of systemic treatment to date. In this article, we present a clinical case of achieving stabilization of the tumor process after 5 courses of chemotherapy with doxorubicin, ifosfamide in a 49-year-old patient with a malignant glomus tumor of the soft tissues of the left forearm with metastatic lesion of the tissues of the anterior chest wall on the left with spread to the left small pectoral muscle, 3rd rib and pleural cavity, with metastatic lesion lung parenchyma.

Planerite with aheylite and faustite from the Chala deposit, Spahievo Ore Field

Planerite, aheylite and faustite are minerals of the turquoise group. They were found in samples from the Chala deposit, Spahievo Ore Field. The samples consist of a small crystalline mass of the investigated mineral phases among quartz. Single spherulites up to 2 mm in size and aggregates of spherulites with a yellowish-greenish color are observed in small cavities. Transparent, colorless wavellite crystals and aggregates are crystallized on spherulites. For the first time in Bulgaria, the presence of aheylite was established.

Evaluation of Shear Bond Strength and Microleakage of Self-adhesive Giomer

This study was aimed to evaluate the bonding performance of a self-adhesive giomer and compare it to a conventional flowable composite resin with regard to shear bond strength and microleakage in enamel and dentin. Healthy human premolars extracted for orthodontic treatments were used in the study. For shear bond strength tests, enamel and dentin specimens were prepared for the study group with selfadhesive giomer and for the control group with conventional flowable composite resin with a 5th-generation adhesive system. A universal testing machine was used to measure the shear bond strength. For the microleakage tests, specimens were immersed in a 2% methylene blue solution for 24 hours, cut into sections, and evaluated with a stereomicroscope for the extent of dye penetration. The results of the study showed no statistically significant difference in shear bond strength between the self-adhesive giomer and the conventional flowable composite resin in enamel (<i>p</i> = 0.091). On the contrary, in dentin, the self-adhesive giomer showed significantly lower shear bond strength (<i>p</i> < 0.0001). The microleakage of the selfadhesive giomer was significantly higher than that of the conventional flowable composite resin (<i>p</i> = 0.002). Self-adhesive giomer is considered useful for restoring small cavities at the enamel level of pediatric patients by reducing chair time with the advantage of a simple bonding process. However, as the study was conducted in a laboratory setting, further research in a clinical environment is deemed necessary.

Operator estimates for non‐periodically perforated domains with Dirichlet and nonlinear Robin conditions: Strange term

We consider a boundary value problem for a general second‐order linear equation in a domain with a fine perforation. The latter is made by small cavities; both the shapes of the cavities and their distribution are arbitrary. The boundaries of the cavities are subject either to a Dirichlet or a nonlinear Robin condition. On the perforation, certain rather weak conditions are imposed to ensure that under the homogenization, we obtain a similar problem in a non‐perforated domain with an additional potential in the equation usually called a strange term. Our main results state the convergence of the solution of the perturbed problem to that of the homogenized one in ‐ and ‐norms uniformly in ‐norm of the right hand side in the equation. The estimates for the convergence rates are established, and their order sharpness is discussed.

Athermal quasistatic cavitation in amorphous solids: Effect of random pinning.

Amorphous solids are known to fail catastrophically via fracture, and cavitation at nano-metric scales is known to play a significant role in such a failure process. Micro-alloying via inclusions is often used as a means to increase the fracture toughness of amorphous solids. Modeling such inclusions as randomly pinned particles that only move affinely and do not participate in plastic relaxations, we study how the pinning influences the process of cavitation-driven fracture in an amorphous solid. Using extensive numerical simulations and probing in the athermal quasistatic limit, we show that just by pinning a very small fraction of particles, the tensile strength is increased, and also the cavitation is delayed. Furthermore, the cavitation that is expected to be spatially heterogeneous becomes spatially homogeneous by forming a large number of small cavities instead of a dominant cavity. The observed behavior is rationalized in terms of screening of plastic activity via the pinning centers, characterized by a screening length extracted from the plastic-eigenmodes.

Comparative study on cavernous weathering features formed by coastal processes and acidic alteration: Implications for rounded pits on Martian rocks

Surface images taken by rovers and landers show the existence of rounded pits with diameter of centimeters on Martian rock surfaces. These pits seem to be similar to terrestrial cavernous weathering features, generated by salt weathering (e.g., alveoli), or by stream flow erosion (e.g., potholes), found near coastal areas. Alternatively, if the weathered rocks contained carbonate minerals, the pits might have been formed by acidic weathering. Here, we compare geomorphology of cavernous weathering features formed by coastal processes on Earth and by laboratory experiments simulating acidic weathering of carbonate. Our field observations for coastal areas of the Japanese islands show that a high cavity number density and small cavities characterize cavernous features formed by salt weathering as compared with those formed by stream flow. Our experimental results show that acidic weathering can generate cavernous features, with high number densities and small diameters. Based on principal component analysis, cavernous weathering features formed by salt weathering, stream flow, and acidic alteration can be distinguished mainly by the number density and diameter. By applying our approach to Martian rocks, we find that the morphological characteristics of rounded pits on Jezero Crater rocks are different from the above cavernous weathering features, and that the Martian pits are categorized as being intermediate between cavernous features formed by salt weathering and acidic weathering. If the pits on Jezero Crater rocks were formed by salt weathering, salt weathering on Mars could have been less effective (possibly, due to a difference in water salinity or salt composition) than those found in coastal areas of Earth. Alternatively, these Martian pits might be formed by other processes (e.g., vesicles in volcanic breccia, eolian processes, or freeze-thaw cycles of porewater).

Ultrasmall and tunable TeraHertz surface plasmon cavities at the ultimate plasmonic limit

The ability to confine THz photons inside deep-subwavelength cavities promises a transformative impact for THz light engineering with metamaterials and for realizing ultrastrong light-matter coupling at the single emitter level. To that end, the most successful approach taken so far has relied on cavity architectures based on metals, for their ability to constrain the spread of electromagnetic fields and tailor geometrically their resonant behavior. Here, we experimentally demonstrate a comparatively high level of confinement by exploiting a plasmonic mechanism based on localized THz surface plasmon modes in bulk semiconductors. We achieve plasmonic confinement at around 1 THz into record breaking small footprint THz cavities exhibiting mode volumes as low as {V}_{cav}/{lambda }_{0}^{3} sim 1{0}^{-7}-1{0}^{-8}, excellent coupling efficiencies and a large frequency tunability with temperature. Notably, we find that plasmonic-based THz cavities can operate until the emergence of electromagnetic nonlocality and Landau damping, which together constitute a fundamental limit to plasmonic confinement. This work discloses nonlocal plasmonic phenomena at unprecedentedly low frequencies and large spatial scales and opens the door to novel types of ultrastrong light-matter interaction experiments thanks to the plasmonic tunability.

EGS P17 Expanding the technical armamentarium to treat complex oesophageal perforations with Endoluminal Vacuum Therapy

Abstract Background Endoluminal vacuum therapy (EVT) is increasingly the default treatment modality for oesophageal leaks. If the leak cavity is large or has a dependent element, placement of the endoluminal vacuum device within the leak cavity facilitates healing. However, accessing the leak cavity can be challenging when the oesophageal defect communicating with the leak cavity is small, and it is tempting to default to luminal EVT. This can lead to a EVT failure. We present a case where luminal EVT in the presence of an established leak cavity with a narrow inlet resulted in stagnation of therapy requiring an alternative technical approach. Methods An 80-year-old high-risk female with Boerhaave's syndrome presented with a 4cm esophageal defect and a large mediastinal leak cavity. An ad-hoc endovacuum therapy (EVT) device, consisting of V.A.C granufoam (KCI) attached to a 14Fr nasogastric (NG) tube, was placed in the leak cavity at -125mmHg pressure. The EVT device was replaced every 3-8 days. After 101 days, luminal EVT was adopted due to cavity narrowing. Partial closure of the esophageal defect was achieved, but a persistent mediastinal abscess communicated through a residual pinhole defect. Additional luminal EVT and image-guided drainage couldn't resolve the persistent esophageal fistula, confirmed by contrast-enhanced CT. Results Endoluminal access to the leak cavity was re-established by dilating the fistula using a TTS 12mm radial expansion wire-guided balloon catheter enabling re-establishment of intra-cavity EVT. Having regained access, further intra-cavity EVT using an ad-hoc EVT device fashioned from black granufoam (KCI) sutured to a 10Fr or 12Fr ng tube with 125mmHg negative pressure was applied. The EVT device was changed every 3-6 days. After further 25 days of EVT complete healing was observed. Conclusions Whilst intraluminal EVT has a role in oesophageal leaks associated with small leak cavities which have no dependent element, larger leak cavities require intra-cavity EVT. If access to the leak cavity is challenging due to the small size of the oesophageal defect, endoscopic measures to facilitate endoluminal access to the leak cavity such as dilation of the defect can be safely employed to enable delivery of intra-cavity EVT. This should be considered when endoluminal access to the leak cavity is prevented due to the small size of the defect obviating the need for other more invasive interventions such as surgery.