Global quieting of high-frequency seismic noise due to COVID-19 pandemic lockdown measures.

Human activity causes vibrations that propagate into the ground as high-frequency seismic waves. Measures to mitigate the coronavirus disease 2019 (COVID-19) pandemic caused widespread changes in human activity, leading to a months-long reduction in seismic noise of up to 50%. The 2020 seismic noise quiet period is the longest and most prominent global anthropogenic seismic noise reduction on record. Although the reduction is strongest at surface seismometers in populated areas, this seismic quiescence extends for many kilometers radially and hundreds of meters in depth. This quiet period provides an opportunity to detect subtle signals from subsurface seismic sources that would have been concealed in noisier times and to benchmark sources of anthropogenic noise. A strong correlation between seismic noise and independent measurements of human mobility suggests that seismology provides an absolute, real-time estimate of human activities.

The Influence of Bone Quality on the Biomechanical Behavior of a Tooth-Implant Fixed Partial Denture: A Three-Dimensional Finite Element Analysis.

PURPOSE: The purpose of this study was to evaluate whether or not bone quality has an effect on the biomechanical behavior of a tooth connected to an implant, when a rigid and a nonrigid attachment are used. MATERIALS AND METHODS: Models of fixed partial dentures supported by a tooth and an implant were developed. These models were then imported into finite element analysis software to study the impact of forces on different types of attachments (rigid vs nonrigid) and bones (types 1 to 4). Each fixed partial denture was subjected to a vertical load of 200 N on the premolars and 230 N on the molar. The materials were considered linear, isotropic, and homogenous. Eight different scenarios were tested. The von Mises criterion was used to display the stress in five structures: fastening screw, implant, attachment, cortical, and trabecular bone. The displacements of the tooth and the implant were also examined. RESULTS: The calculated maximum observed stress values differed among the simulated scenarios. The biggest values of stress concentrations were observed at the lingual cervical areas, the implant-cortical bone interface, the implant-crown interface, the butt-joint contact of the implant-abutment screw, and the apical parts of the tooth and implant. The main difference between the rigid and nonrigid connection was observed between the natural tooth retainer and the pontic. In the rigid connection, the movement of the natural tooth retainer was smooth. In the nonrigid connection, the attachment exhibited a partial buccal displacement. Von Mises stresses among the different tested structures ranged between 24 and 840 MPa. CONCLUSION: The quality of the bone and the rigidity of the connection between a natural tooth and an implant influence both the generated stresses and the displacement of the tooth and the implant. The highest stresses for the implant-trabecular bone interface, the neck of the implant, and the fastening screw were observed in type 3 bone when a rigid connection was used. The lowest stresses for the implant-cortical bone interface, the neck of the implant, and the connector were registered in type 1 bone, when a rigid connection was used. The smallest tooth and implant displacement was observed in type 1 bone, when a rigid connection was used, while the biggest tooth and implant displacement was registered in type 4 bone when a nonrigid connection was used.

Influence of Alveolar Bone Loss and Different Alloys on the Biomechanical Behavior of Internal-and External-Connection Implants: A Three-Dimensional Finite Element Analysis.

PURPOSE: The purpose of this study was to evaluate the stress distribution during application of occlusal loads to maxillary anterior single external- and internal-connection implant-supported restorations with different amounts of bone loss and with the use of different metal alloys for restorations and fixation screws. MATERIALS AND METHODS: Models of external- and internal-connection implants, corresponding abutments/crowns, and fixation screws were developed. These models were then imported into finite element analysis software to study the impact of forces on different implant connections and materials. Each prosthesis was subjected to a 200-N compressive shear force applied at 130 degrees relative to the long axis of the implant. The materials were considered linear, isotropic, and homogenous. The parameters changed for each connection type included: bone resorption in relation to the prosthetic platform (no, 2 mm, or 4 mm of resorption); alloys of the restorations (nonprecious vs precious); and alloys of the abutment screws (titanium vs gold). Von Mises stresses were used to display the stress in five models: implant, restoration, screw, cancellous bone, and cortical bone. RESULTS: Statistically significant differences in the stresses of all involved structures occurred when the bone level decreased by 2 mm and by 4 mm. The connection type contributed to statistically significant differences in the stresses in both the restoration and the screw. The alloy type resulted in statistically significant differences in the implant, the superstructure, and the cortical bone stresses. CONCLUSION: As bone resorbed, the stresses generated within the internal-connection implant were greater than those generated in the external-connection implant. The same findings applied for the restoration and for cancellous and cortical bone. The stresses generated in the fixation screw were greater in the external-connection implant than in the internal-connection implant for all bone resorption scenarios.

Echocardiographic imaging of tricuspid and pulmonary valve abnormalities in primary ovarian carcinoid tumor.

Carcinoid is a rare malignancy originating from enterochromaffin cells and is clinically characterized by flushing, diarrhea and bronchospasm, due to secretion of vasoactive substances. A dreaded complication is carcinoid heart disease, which mainly affects right cardiac chambers, resulting in thickened, immobile and retracted tricuspid and pulmonary valves. In the current report, a case of a 60-year old female presenting with symptoms of right heart failure is described. Transthoracic two-dimensional and real-time three-dimensional echocardiography findings, as well as biochemical markers, including pro-BNP and NT-pro-BNP, were consistent with carcinoid syndrome. The histological diagnosis of carcinoid was confirmed after surgical resection of an ovarian mass.

Primary hepatic actinomycosis.

The clinical and imaging findings of primary hepatic actinomycosis are nonspecific and can mimic other diseases. This condition usually needs to be distinguished from other liver-occupying lesions, including malignancy. Review of the English language literature showed 67 cases of hepatic actinomycosis in immunocompetent, predominantly male patients. Infection was usually (75%) cryptogenic. The results of radiologic imaging showed that the lesion involved the right lobe in half of the cases, mimicked a liver tumor in 45%, and was single in two thirds of the cases. Hepatic actinomycosis coexisted with infections by common bacteria in 32% of cases reported. Diagnosis was usually achieved by microscopic examination of surgical or percutaneous specimens in 84.2% and 78.6%, respectively. Antibiotic therapy alone was used for treatment in approximately one half of cases and combined antibiotic treatment with surgical or percutaneous drainage procedure in the other half. The overall mortality rate was 7.6%. In conclusion, primary hepatic actinomycosis is a rare and usually cryptogenic infection. It is more common in men and immunocompetent subjects. It is well responsive to medical or combined medical and interventional treatment.

Gastrointestinal stromal tumor causing small bowel intussusception in a patient with Crohn's disease.

We report a case of jejunoileal intussusception in a 42-year-old patient with Crohn's disease caused by a gastrointestinal stromal tumor. The patient complained of vague diffuse abdominal pain for a period of 4 mo. Intussusception was suspected at computer tomography and magnetic resonance imaging scans. Segmental resection of the small intestine was performed. Pathological examination of the surgical specimen revealed a gastrointestinal stromal tumor as well as aphthous ulcerations and areas of inflammation, which were characteristic of Crohn's disease. This is the first report of small bowel intussusception due to a gastrointestinal stromal tumor coexisting with Crohn's disease.

Unusual combination of paraneoplastic manifestations in a patient with metastatic gastrointestinal stromal tumor (GIST).

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. Activating mutations in tyrosine kinase receptors KIT or platelet-derived growth factor receptor alpha (PDGFRA) are the main mechanisms causing the disease. Patients generally present with non-specific symptoms, while a number of tumors are discovered incidentally and may be metastatic at the time of diagnosis. Aggressive GISTs have a defined pattern of metastasis to the liver or throughout the abdomen, or both. Though GISTs rarely present systemic or isolated paraneoplastic reactions, a few cases have been reported in the literature. We present the case of a 54-year-old patient with metastatic GIST at diagnosis and the emergence of paraneoplastic manifestations during follow-up.

Quail poisoning in a child.

CONTEXT: It has been well known since ancient times that the consumption of quail may be deleterious to health. The European quail sub-species (Coturnix coturnix coturnix), common to Europe, North Africa, and western Asia is indeed potentially poisonous to humans, but only during the autumn migration (not during their return flight in spring). Quail poisoning is an acute dietary-toxicological syndrome. ISSUE: In this case report, we describe a rare, non-fatal case of quail poisoning in a 12-year-old boy. The victim was admitted to hospital 5 hours after the consumption of quail because of the signs and symptoms, as well as laboratory findings (elevation of serum muscle enzymes, myoglobinuria) significant of acute rhabdomyolysis. He was treated symptomatically with bed rest, forced continuous diuresis, urine alkalization, and maintenance of fluid and electrolyte balance. The victim recovered completely without sequelae after 8 days hospitalization. LESSONS: The aetiology of this syndrome is still unclear. It has been suggested that a toxic effect or a genetic sensitivity plays a major role. Many cases of quail poisoning in adults have been reported previously on the island of Lesbos during autumn. To our knowledge, this is the first case reported in a child.

Can somatostatin prevent post-ERCP pancreatitis? Results of a randomized controlled trial.

BACKGROUND: Acute pancreatitis is the most common complication of endoscopic retrograde cholangiopancreatography (ERCP), occurring in 1-10% of patients. Several substances have been used, with negative results, in an attempt to prevent this complication. METHODS: We performed a double-blind randomized trial in 372 consecutive patients undergoing diagnostic or therapeutic ERCP to evaluate the role of somatostatin in preventing post-ERCP pancreatitis. The first group received continuous somatostatin infusion for 12 h starting 30 min before ERCP, the second group received a bolus intravenous injection of somatostatin at the time of cannulation of the papilla, and the third group received a placebo. RESULTS: Two patients in each of the somatostatin groups (1.7%) and 12 patients in the placebo group (9.8%) developed pancreatitis (P<0.05). Serum amylase levels 5 and 24 h after the procedure were lower in both groups that received somatostatin than in the placebo group (P<0.05). CONCLUSION: Somatostatin is useful in preventing post-ERCP pancreatitis. Further studies must be designed to investigate the cost-effectiveness of the drug and to determine the ideal administration route and dosage.