Identification of the FSH-RH as the other gonadotropin-releasing hormone.

In vertebrates, folliculogenesis and ovulation are regulated by two distinct pituitary gonadotropins: follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Currently, there is an intriguing consensus that a single hypothalamic neurohormone, gonadotropin-releasing hormone (GnRH), regulates the secretion of both FSH and LH, although the required timing and functions of FSH and LH are different. However, recent studies in many non-mammalian vertebrates indicated that GnRH is dispensable for FSH function. Here, by using medaka as a model teleost, we successfully identify cholecystokinin as the other gonadotropin regulator, FSH-releasing hormone (FSH-RH). Our histological and in vitro analyses demonstrate that hypothalamic cholecystokinin-expressing neurons directly affect FSH cells through the cholecystokinin receptor, Cck2rb, thereby increasing the expression and release of FSH. Remarkably, the knockout of this pathway minimizes FSH expression and results in a failure of folliculogenesis. Here, we propose the existence of the "dual GnRH model" in vertebrates that utilize both FSH-RH and LH-RH.

Clinical impact of fluoropolymer-based drug-eluting stent thrombosis in femoropopliteal artery occlusive lesions.

BACKGROUND: Endovascular treatment (EVT) is recommended for superficial femoral artery (SFA) lesions, and good results have been reported after implantation of drug-eluting stents (DES) for SFA. However, the major concern after implantation is acute thrombosis during the follow-up period, resulting in major amputation and major adverse limb events. In this study, we examined the incidence and outcome of acute thrombosis after DES implantation in the SFA. OBJECTIVES AND METHODS: DES implantation for a femoropopliteal lesion was performed in 288 patients at multiple centers in Japan from 2019 to 2021. A total of 25 patients (8.6%) with DES acute occlusion were analyzed retrospectively. The primary endpoint was amputation-free survival (AFS) after acute occlusion. RESULTS: The median patient age was 77 years, with 48% having diabetes, 40% undergoing maintenance dialysis, and 66% having chronic limb-threatening ischemia (CLTI). The mean time from initial DES implantation to acute occlusion was 153.5 ± 177.6 days, with a median of 104 days. EVT was performed in 18 patients (72%), surgical revascularization in 3 (12%), and conservative treatment in 4 (16%). Two deaths within 30 days were both due to sepsis. No major amputation or major adverse cardiovascular events occurred within 30 days. The 1-year rates of patency and freedom from target lesion revascularization after DES thrombosis were 22.9% and 48.8%, respectively. AFS at 1 year was 55.1%. CONCLUSION: Acute DES occlusion is relatively frequent, and the outcome is poor. Therefore, the indication of DES implantation for a complex SFA lesion may require careful consideration. Further investigation may be needed in DES implantation for a complex SFA lesion.

Medium-Term Outcomes of Treatment with a VIABAHN VBX Covered Stent for Aortoiliac Occlusive Lesions in Patients with Peripheral Artery Disease.

BACKGROUND: Endovascular treatment (EVT) for aortoiliac (AI) occlusive lesions is now conducted worldwide, but there are challenges in EVT for complex AI lesions. The VIABAHN VBX (W.L. Gore & Associates, Flagstaff, AZ) is a next-generation balloon-expandable covered stent designed for use with complex AI lesions. The purpose of this study is to evaluate the medium-term outcomes of VIABAHN VBX for such lesions. METHODS: Symptomatic patients who underwent EVT with VIABAHN VBX for an AI lesion from 2018 to 2020 at 7 Japanese centers were reviewed retrospectively. The primary endpoints were primary patency and freedom from target lesion revascularization (TLR). RESULTS: A total of 95 EVT procedures with VIABAHN VBX for AI occlusive lesions were performed in 71 patients. The patients had high rates of dyslipidemia (53%) and chronic kidney disease (61%), and 22% had chronic limb-threatening ischemia (CLTI). The Transatlantic Inter-Society Consensus (TASC Ⅱ) class was A in 12 patients (17%), B in 12 (17%), C in 10 (14%), and D in 37 (52%). Severe calcification (360°) of the treated lesion was present in 31 patients (33%). The median procedure time was 84 (49-158) min, with a technical success rate of 100%. The median follow-up period was 36 (32-43) months. The 3-year primary and secondary patency of VIABAHN VBX were 91% and 99%, the 3-year freedom from TLR was 92%, and the 3-year freedom from major adverse limb event (MALE) was 98%. No limbs required major amputation. Lesion severity (TASC Ⅱ C or D) and severe calcification did not affect the primary patency or freedom from TLR. CONCLUSIONS: Medium-term outcomes after EVT with VIABAHN VBX for AI lesions were acceptable regardless of lesion severity and calcification. These results suggest that VIABAHN VBX may be suitable for AI occlusive lesions with severe anatomical complexity and/or severe calcification.

Long-Term Outcomes of Endovascular Aneurysm Repair in Patients Aged ≤70 Years.

Objectives: The efficacy of endovascular aneurysm repair (EVAR) against abdominal aortic aneurysm (AAA) in younger patients remains unknown. Hence, the current study aimed to investigate whether the aneurysm-related mortality rate of EVAR is acceptable among patients aged ≤70 years. Methods: Among 644 patients, 148 underwent EVAR (EVAR group), and 496 received open surgical repair (OSR group). The cumulative incidence rates of aneurysm-related death, any intervention, and serious aneurysm-related events after AAA repair were evaluated using the cumulative incidence function in the presence of competing risks. Results: The EVAR group had higher prevalences of several comorbidities, and overall survival for the EVAR group was significantly inferior to that of the OSR group. The cumulative incidence rates of aneurysm-related death, any intervention, and serious aneurysm-related events at 5 years were 1.5%, 11.7%, and 6.4% in the EVAR group and 1.3%, 5.3%, and 5.9% in the OSR group, respectively. EVAR was not a significant prognostic factor of aneurysm-related mortality and serious aneurysm-related events. However, it was an independent poor prognostic factor of any intervention. Conclusion: EVAR was not a significant prognostic factor of aneurysm-related mortality and serious aneurysm-related events. Therefore, it demonstrated acceptable procedure-related long-term outcomes, at least in high-risk young patients.

Contribution to a Sustainable Society: Biosorption of Precious Metals Using the Microalga Galdieria.

The red microalga Galdieria sp. is an extremophile that inhabits acidic hot sulphur springs and grows heterotrophically to a high cell density. These characteristics make Galdieria suitable for commercial applications as stable mass production is the key to success in the algae business. Galdieria has great potential as a precious metal adsorbent to provide a sustainable, efficient and environmentally benign method for urban mining and artisanal small-scale gold mining. The efficiency and selectivity in capturing precious metals, gold and palladium from metal solutions by a Galdieria-derived adsorbent was assessed relative to commercially used adsorbents, ion exchange resin and activated charcoal. As it is only the surface of Galdieria cells that affect metal adsorption, the cell content was analysed to determine the manner of utilisation of those metabolites. Galdieria was shown to be protein-rich and contain beneficial metabolites, the levels of which could shift depending on the growth conditions. Separating the cell content from the adsorbent could improve the adsorption efficiency and reduce CO2 emissions during the metal collection process. The commercial applications of Galdieria appear promising: growth is quick and dense; the precious metal adsorption capacity is highly efficient and selective in acidic conditions, especially at low metal concentrations; and the cell content is nutrient-rich.

Clinical Outcomes of Common Femoral Thromboendarterectomy with Bovine Pericardium Patch Angioplasty.

BACKGROUND: The purpose of the study is to evaluate the efficacy of thromboendarterectomy (TEA) for common femoral occlusive disease using bovine pericardium patch angioplasty. METHODS: The subjects were patients who underwent TEA for common femoral occlusive disease with bovine pericardium patch angioplasty from October 2020 to August 2021. The study had a prospective, multicenter, and observational design. The primary end point was primary patency (freedom from restenosis). The secondary end points were secondary patency, amputation-free survival (AFS), postoperative wound complication, hospital death within 30 days, and major adverse cardiovascular events (MACE) within 30 days. RESULTS: Forty-seven TEA procedures with a bovine patch were performed in 42 patients (34 males; median age, 78 years; diabetes mellitus, 57%; end-stage renal disease with hemodialysis, 19%). Clinical presentations were intermittent claudication (68%) and critical limb-threatening ischemia (32%). Sixteen (34%) limbs underwent TEA alone and 31 (66%) underwent a combined procedure. Surgical site infection (SSI) occurred in 4 limbs (9%) and lymphatic fistulas in 3 limbs (6%). One limb with SSI required surgical debridement 19 days after the procedure, and 1 limb (2%) without postoperative wound complications required additional treatment due to acute bleeding. Hospital death within 30 days occurred in 1 case due to panperitonitis. There was no MACE within 30 days. Claudication was improved in all cases. Postoperative ABI of 0.92 [0.72-1.00] was significantly higher than the preoperative value (P < 0.001). The median follow-up period was 10 months [9-13 months]. One limb (2%) required additional endovascular therapy due to stenosis at the endarterectomy site at 5 months postoperatively. Primary and secondary patencies were 98% and 100% at 12 months, respectively, and the AFS rate was 90% at 12 months. CONCLUSIONS: Common femoral TEA with bovine pericardium patch angioplasty has satisfactory clinical outcomes.

Development of Novel Decarboxylation-Urea Method toward Interlayer-Anion-Controlled Layered Double Hydroxides.

Layered double hydroxides (LDHs) are representative of a 2D anionic clay. Simple and homogeneous synthesis of interlayer-anion-controlled LDH is essential for studies and industrial production. In this study, we report the one-pot synthesis of an LDH that is selective for interlayer anions, which was labeled as "decarboxylation-urea method". We obtained LDHs intercalated with NO3-, Cl-, and SO42- by removing CO2 in this method. The ionic conductivities of the prepared LDHs were investigated for their applicability to electrolytes, and it was found that Zn-Al LDH intercalated with NO3- showed the highest ionic conductivity (18 mS cm-1). Therefore, the LDH intercalated with NO3- synthesized using the decarboxylation-urea method is promising as an alkaline solid electrolyte.

Systolic Ejection Murmurs Due to Unruptured Aneurysm of the Sinus of Valsalva.

Aneurysm of the sinus of Valsalva is a rare condition with variable clinical presentation. We present a case of an unruptured aneurysm of the right sinus of Valsalva, in which a systolic ejection murmur was instrumental in the diagnosis. An asymptomatic 72-year-old man was referred to the cardiology department because of a heart murmur. Physical examination was unremarkable except for a grade 3 systolic murmur, loudest at the third left sternal border. Echocardiography revealed a sac-like structure protruding into the right ventricle and attached to the right sinus of Valsalva with a right ventricular outflow tract obstruction during end-systole. Multidetector computed tomography showed an aneurysm of the right sinus of Valsalva with a diameter of 28 × 19 mm; no contrast leakage from the aneurysm was detected. A diagnosis of an unruptured aneurysm of the right sinus of Valsalva was made. Surgical repair was successfully performed, and the murmur disappeared postoperatively. This case underscores the importance of physical examination even in the era of advanced imaging techniques and the need to recognize the wide range of causes of heart murmurs.

Establishment and characteristics of Perkinsus beihaiensis in vitro isolates from Mediterranean mussels Mytilus galloprovincialis.

Two monoclonal in vitro isolates of Perkinsus beihaiensis were established from tissues of infected Mediterranean mussels Mytilus galloprovincialis, using a lipid concentrate and yeast extract medium (LpcYM) to induce enlarged prezoospoangia from histozoic trophozoites, and Perkinsus broth medium (PBM) to support subsequent zoosporulation and schizogonic proliferation from those cells. Zoospores of the isolates developed into uninucleate signet-ring trophozoites followed by schizonts typical of Perkinsus spp., but an additional type of unknown botryoidal cell clusters appeared and increased in density. These botryoidal cell clusters had second-generation daughter schizonts within which further internal cells were produced. Although botryoidal cell clusters in primary cultures rarely proliferated in PBM, cells contained by botryoidal clusters enlarged as prezoosporangia in LpcYM, and a large number of proliferative stages (i.e. trophozoites and schizonts typical for Perkinsus spp.) were obtained from these prezoosporangia in PBM. At lower cell density, trophozoites transformed into the botryoidal cell clusters in PBM, and the number of cells increased little, while trophozoites rapidly increased by typical schizogony at higher density in PBM. Based on these observations, we determined an optimal cell density for continuous culture of P. beihaiensis isolates, confirmed their ability to proliferate and survive after cryopreservation, and describe an experimental protocol to culture this most recently described species in the genus Perkinsus.

Supplementation with lipids enhances zoosporulation of Perkinsus species.

The protozoan parasite Perkinsus olseni is a major pathogen of marine mollusks. A large number of zoospores (the most infective stage) is required to experimentally examine the transmission and invasion processes of this parasite, but the conventional zoosporulation method in seawater is inefficient. A recent study found that P. olseni zoosporulation was highly enhanced in a nutrient-rich medium which was developed for trophozoite proliferation in Perkinsus. Here, we examined the effect of each medium component on P. olseni zoosporulation and found that lipids enhanced zoosporulation. Moreover, zoospores failed to develop into trophozoites in seawater supplemented with lipids, indicating that this zoosporulation method using seawater supplemented with lipids is ideal for preparing a large number of P. olseni zoospores for various biological assays. Lipid supplementation also significantly enhanced zoosporulation in P. honshuensis, P. chesapeaki, and P. marinus, although the enhancing effect of the lipid supplementation varied by species. Considering the limited availability of lipids in the sea water column, our findings suggest that Perkinsus zoosporulation likely occurs mainly in the vicinity of hosts (not in the sea water column), such as in the mantle cavity or on the body surface of mollusk hosts.

MFC: An open-source high-order multi-component, multi-phase, and multi-scale compressible flow solver.

MFC is an open-source tool for solving multi-component, multi-phase, and bubbly compressible flows. It is capable of efficiently solving a wide range of flows, including droplet atomization, shock-bubble interaction, and bubble dynamics. We present the 5- and 6-equation thermodynamically-consistent diffuse-interface models we use to handle such flows, which are coupled to high-order interface-capturing methods, HLL-type Riemann solvers, and TVD time-integration schemes that are capable of simulating unsteady flows with strong shocks. The numerical methods are implemented in a flexible, modular framework that is amenable to future development. The methods we employ are validated via comparisons to experimental results for shock-bubble, shock-droplet, and shock-water-cylinder interaction problems and verified to be free of spurious oscillations for material-interface advection and gas-liquid Riemann problems. For smooth solutions, such as the advection of an isentropic vortex, the methods are verified to be high-order accurate. Illustrative examples involving shock-bubble-vessel-wall and acoustic-bubble-net interactions are used to demonstrate the full capabilities of MFC.

The gene regulatory system for specifying germ layers in early embryos of the simple chordate.

In animal embryos, gene regulatory networks control the dynamics of gene expression in cells and coordinate such dynamics among cells. In ascidian embryos, gene expression dynamics have been dissected at the single-cell resolution. Here, we revealed mathematical functions that represent the regulatory logics of all regulatory genes expressed at the 32-cell stage when the germ layers are largely specified. These functions collectively explain the entire mechanism by which gene expression dynamics are controlled coordinately in early embryos. We found that regulatory functions for genes expressed in each of the specific lineages contain a common core regulatory mechanism. Last, we showed that the expression of the regulatory genes became reproducible by calculation and controllable by experimental manipulations. Thus, these regulatory functions represent an architectural design for the germ layer specification of this chordate and provide a platform for simulations and experiments to understand the operating principles of gene regulatory networks.

Using linkage logic theory to control dynamics of a gene regulatory network of a chordate embryo.

Linkage logic theory provides a mathematical criterion to control network dynamics by manipulating activities of a subset of network nodes, which are collectively called a feedback vertex set (FVS). Because many biological functions emerge from dynamics of biological networks, this theory provides a promising tool for controlling biological functions. By manipulating the activity of FVS molecules identified in a gene regulatory network (GRN) for fate specification of seven tissues in ascidian embryos, we previously succeeded in reproducing six of the seven cell types. Simultaneously, we discovered that the experimentally reconstituted GRN lacked information sufficient to reproduce muscle cells. Here, we utilized linkage logic theory as a tool to find missing edges in the GRN. Then, we identified a FVS from an updated version of the GRN and confirmed that manipulating the activity of this FVS was sufficient to induce all seven cell types, even in a multi-cellular environment. Thus, linkage logic theory provides tools to find missing edges in experimentally reconstituted networks, to determine whether reconstituted networks contain sufficient information to fulfil expected functions, and to reprogram cell fate.

Development of a simple host-free medium for efficient prezoosporulation of Perkinsus olseni trophozoites cultured in vitro.

The parasitizing stage (trophozoite) of the protozoan parasite Perkinsus olseni progresses to the dormant stage (prezoosporangium) immediately after the death of the host through physiologically and morphologically drastic changes. This development is reproducible in Ray's fluid thioglycollate medium (RFTM). In this study, supplementation with tissue extract from a host, the Manila clam, significantly improved the efficiency of development, as determined by the numbers and sizes of developed prezoosporangia. Similar results were seen following supplementation with boiled host tissue extract, which indicates that a thermally stable component of the host is required for the parasite's development. Subsequently, we found that a commercially available lipid concentrate significantly increased prezoosporulation without host tissue, suggesting that the lipids in host tissue enhance prezoosporangia development. Moreover, we determined that yeast extract, sodium thioglycollate, and sodium chloride were the only components of RFTM required for prezoosporulation. Based on these findings, we prepared a simple, host-free medium for P. olseni prezoosporulation-Lipid concentrate Yeast extract Medium (LpcYM)-consisting of yeast extract, lipid concentrate, sodium thioglycollate, and sodium chloride. We confirmed that the prezoosporangia developed in LpcYM produce zoospores that are infectious to Manila clams and that trophozoites of other Perkinsus species (P. marinus, P. honshuensis, and P. chesapeaki) also develop to prezoosporangia in this host-free medium. As LpcYM has the simplest composition of prezoosporulation media available thus far, it enables us to conduct molecular and biochemical studies examining the drastic transformation process of this parasite.

Status of Institutional Review Board Meetings Conducted Through Web Conference Systems in Japanese National University Hospitals During the COVID-19 Pandemic: Questionnaire Study.

BACKGROUND: With the global proliferation of the novel COVID-19 disease, conventionally conducting institutional review board (IRB) meetings has become a difficult task. Amid concerns about the suspension of drug development due to delays within IRBs, it has been suggested that IRB meetings should be temporarily conducted via the internet. OBJECTIVE: This study aimed to elucidate the current status of IRB meetings conducted through web conference systems. METHODS: A survey on conducting IRB meetings through web conference systems was administered to Japanese national university hospitals. Respondents were in charge of operating IRB offices at different universities. This study was not a randomized controlled trial. RESULTS: The survey was performed at 42 facilities between the end of May and early June, 2020, immediately after the state of emergency was lifted in Japan. The survey yielded a response rate of 74% (31/42). Additionally, while 68% (21/31) of facilities introduced web conference systems for IRB meetings, 13% (4/31) of the surveyed facilities postponed IRB meetings. Therefore, we conducted a further survey of 21 facilities that implemented web conference systems for IRB meetings. According to 71% (15/21) of the respondents, there was no financial burden for implementing these systems, as they were free of charge. In 90% (19/21) of the facilities, IRB meetings through web conference systems were already being conducted with personal electronic devices. Furthermore, in 48% (10/21) of facilities, a web conference system was used in conjunction with face-to-face meetings. CONCLUSIONS: Due to the COVID-19 pandemic, the number of reviews in clinical trial core hospitals has decreased. This suggests that the development of pharmaceuticals has stagnated because of COVID-19. According to 71% (15/21) of the respondents who conducted IRB meetings through web conference systems, the cost of introducing such meetings was US $0, showing a negligible financial burden. Moreover, it was shown that online deliberations could be carried out in the same manner as face-to-face meetings, as 86% (18/21) of facilities stated that the number of comments made by board members did not change. To improve the quality of IRB meetings conducted through web conference systems, it is necessary to further examine camera use and the content displayed on members' screens during meetings. Further examination of all members who use web conference systems is required. Our measures for addressing the requests and problems identified in our study could potentially be considered protocols for future IRB meetings, when the COVID-19 pandemic has passed and face-to-face meetings are possible again. This study also highlights the importance of developing web conference systems for IRB meetings to respond to future unforeseen pandemics.

Arabidopsis ECHIDNA protein is involved in seed coloration, protein trafficking to vacuoles, and vacuolar biogenesis.

Flavonoids are a major group of plant-specific metabolites that determine flower and seed coloration. In plant cells, flavonoids are synthesized at the cytosolic surface of the endoplasmic reticulum and are sequestered in the vacuole. It is possible that membrane trafficking, including vesicle trafficking and organelle dynamics, contributes to flavonoid transport and accumulation. However, the underlying mechanism has yet to be fully elucidated. Here we show that the Arabidopsis ECHIDNA protein plays a role in flavonoid accumulation in the vacuole and protein trafficking to the vacuole. We found defective pigmentation patterns in echidna seed, possibly caused by reduced levels of proanthocyanidins, which determine seed coloration. The echidna mutant has defects in protein sorting to the protein storage vacuole as well as vacuole morphology. These findings indicate that ECHIDNA is involved in the vacuolar trafficking pathway as well as the previously described secretory pathway. In addition, we found a genetic interaction between echidna and green fluorescent seed 9 (gfs9), a membrane trafficking factor involved in flavonoid accumulation. Our findings suggest that vacuolar trafficking and/or vacuolar development, both of which are collectively regulated by ECHIDNA and GFS9, are required for flavonoid accumulation, resulting in seed coat pigmentation.

Bubble cloud dynamics in an ultrasound field.

The dynamics of bubble clouds induced by high-intensity focused ultrasound are investigated in a regime where the cloud size is similar to the ultrasound wavelength. High-speed images show that the cloud is asymmetrical; the bubbles nearest the source grow to a larger radius than the distal ones. Similar structures of bubble clouds are observed in numerical simulations that mimic the laboratory experiment. To elucidate the structure, a parametric study is conducted for plane ultrasound waves with various amplitudes and diffuse clouds with different initial void fractions. Based on an analysis of the kinetic energy of liquid induced by bubble oscillations, a new scaling parameter is introduced to characterize the dynamics. The new parameter generalizes the cloud interaction parameter originally introduced by d'Agostino & Brennen (1989). The dynamic interaction parameter controls the energy localization and consequent anisotropy of the cloud. Moreover, the amplitude of the far-field, bubble-scattered acoustics is likewise correlated with the proposed parameter. Findings of the present study not only shed light on the physics of cloud cavitation, but may also be of use to quantification of the effects of cavitation on outcomes of ultrasound therapies including HIFU-based lithotripsy.

First discovery of Perkinsus beihaiensis in Mediterranean mussels (Mytilus galloprovincialis) in Tokyo Bay, Japan.

During analyses of the invasive Mediterranean mussel Mytilus galloprovincialis for pathologies in Tokyo Bay, infection by the protozoan parasite Perkinsus beihaiensis was found through histological examination, Ray's Fluid Thioglycollate Medium assays, and molecular analyses. Specific PCR assays for each Perkinsus species also revealed the presence of an indigenous congeneric species, Perkinsus olseni, but P. beihaiensis was dominant in M. galloprovincialis. Sequences of the ribosomal internal transcribed spacer region I of P. beihaiensis found in Japan were genetically more similar to those found in South American countries (Panama and Brazil) than in Asian countries (China and India). Though Mediterranean mussels have become widespread in Japanese waters since their invasion in the 1930s, epidemiological surveys show that mussels collected outside Tokyo Bay are free of any Perkinsus infections. Based on these results, it was strongly suggested that P. beihaiensis invaded Tokyo Bay by transportation of bivalves originating from South America but has not yet spread to other parts of Japan. The possibility is not ruled out, however, that the parasite is indigenous in Japan but the environment in Tokyo Bay favors its transmission to Mediterranean mussels.

High-speed video microscopy and numerical modeling of bubble dynamics near a surface of urinary stone.

Ultra-high-speed video microscopy and numerical modeling were used to assess the dynamics of microbubbles at the surface of urinary stones. Lipid-shell microbubbles designed to accumulate on stone surfaces were driven by bursts of ultrasound in the sub-MHz range with pressure amplitudes on the order of 1 MPa. Microbubbles were observed to undergo repeated cycles of expansion and violent collapse. At maximum expansion, the microbubbles' cross-section resembled an ellipse truncated by the stone. Approximating the bubble shape as an oblate spheroid, this study modeled the collapse by solving the multicomponent Euler equations with a two-dimensional-axisymmetric code with adaptive mesh refinement for fine resolution of the gas-liquid interface. Modeled bubble collapse and high-speed video microscopy showed a distinctive circumferential pinching during the collapse. In the numerical model, this pinching was associated with bidirectional microjetting normal to the rigid surface and toroidal collapse of the bubble. Modeled pressure spikes had amplitudes two-to-three orders of magnitude greater than that of the driving wave. Micro-computed tomography was used to study surface erosion and formation of microcracks from the action of microbubbles. This study suggests that engineered microbubbles enable stone-treatment modalities with driving pressures significantly lower than those required without the microbubbles.

Diastereoselective Synthesis of 1,3-Oxazolidines via Cationic Iron Porphyrin-catalyzed Cycloaddition of Aziridines with Aldehydes.

An efficient iron porphyrin Lewis acid-catalyzed cycloaddition of aziridines with aldehydes has been developed to provide oxazolidines with high regio- and diastereoselectivity. The cycloaddition proceeds in toluene with 1 mol % of the iron catalyst at 25 °C. A theoretical study and synchrotron-based X-ray absorption fine structure measurements provided fundamental insights into the aziridine-iron porphyrin complex, which is the key intermediate for the generation of the 1,3-dipole synthon.