Distributed control for geometric pattern formation of large-scale multirobot systems.

Introduction: Geometric pattern formation is crucial in many tasks involving large-scale multi-agent systems. Examples include mobile agents performing surveillance, swarms of drones or robots, and smart transportation systems. Currently, most control strategies proposed to achieve pattern formation in network systems either show good performance but require expensive sensors and communication devices, or have lesser sensor requirements but behave more poorly. Methods and result: In this paper, we provide a distributed displacement-based control law that allows large groups of agents to achieve triangular and square lattices, with low sensor requirements and without needing communication between the agents. Also, a simple, yet powerful, adaptation law is proposed to automatically tune the control gains in order to reduce the design effort, while improving robustness and flexibility. Results: We show the validity and robustness of our approach via numerical simulations and experiments, comparing it, where possible, with other approaches from the existing literature.

Ratiometric control of cell phenotypes in monostrain microbial consortia.

We address the problem of regulating and keeping at a desired balance the relative numbers between cells exhibiting a different phenotype within a monostrain microbial consortium. We propose a strategy based on the use of external control inputs, assuming each cell in the community is endowed with a reversible, bistable memory mechanism. Specifically, we provide a general analytical framework to guide the design of external feedback control strategies aimed at balancing the ratio between cells whose memory is stabilized at either one of two equilibria associated with different cell phenotypes. We demonstrate the stability and robustness properties of the control laws proposed and validate them in silico, implementing the memory element via a genetic toggle-switch. The proposed control framework may be used to allow long-term coexistence of different populations, with both industrial and biotechnological applications. As a representative example, we consider the realistic agent-based implementation of our control strategy to enable cooperative bioproduction of a dimer in a monostrain microbial consortium.

Acute acalculous cholecystitis and cardiovascular disease, which came first? After two hundred years still the classic chicken and eggs debate: A review of literature.

The existence of a close association between disease of the biliary tract and disease of the heart is known from the mists of time. Acute acalculous cholecystitis (AAC) can be defined as an acute necro inflammatory disease of the gallbladder in the absence of cholelithiasis. AAC is a challenging diagnosis. The atypical clinical onset associated to a paucity and similarity of symptoms and to laboratory data mimicking cardiovascular disease (CVD) often results in under and misdiagnosed cases. Moreover, AAC has commonly a fulminant course compared to calculous cholecystitis and it is often associated with gangrene, perforation and empyema as well as considerable morbidity and mortality (up 50%). Early diagnosis is crucial to a prompt treatment in order to avoid complications and to increase survivability. Even today, although scientific evidence dating two hundred years has shown a close association between AAC and CVD, due to the lack of RCT, there is still a lot of confusion regarding the relationship and consequently the clinical management AAC and CVD. In addition, emergency physicians are not always familiar with transient ECG changes with AAC. The aim of this review was to provide evidence regarding epidemiology, pathophysiology, clinical presentation and treatment of the complex association between AAC and CVD. Our main findings indicate that AAC should be suspected after each general disease leading to hypoperfusion such as cardiovascular diseases or cerebrovascular diseases or major heart or aortic surgery. ECG changes in absence of significant laboratory data for IMA (Acute myocardial infarction) could be related to a misdiagnosed AAC. US - Ultrasonography-plays a key role in the early diagnosis and also in the follow up of AAC. Cholecystostomy and cholecystectomy as unique or sequential represent the two prevailing treatment options for AAC.

Automatic synchronisation of the cell cycle in budding yeast through closed-loop feedback control.

The cell cycle is the process by which eukaryotic cells replicate. Yeast cells cycle asynchronously with each cell in the population budding at a different time. Although there are several experimental approaches to synchronise cells, these usually work only in the short-term. Here, we build a cyber-genetic system to achieve long-term synchronisation of the cell population, by interfacing genetically modified yeast cells with a computer by means of microfluidics to dynamically change medium, and a microscope to estimate cell cycle phases of individual cells. The computer implements a controller algorithm to decide when, and for how long, to change the growth medium to synchronise the cell-cycle across the population. Our work builds upon solid theoretical foundations provided by Control Engineering. In addition to providing an avenue for yeast cell cycle synchronisation, our work shows that control engineering can be used to automatically steer complex biological processes towards desired behaviours similarly to what is currently done with robots and autonomous vehicles.

Balancing Cell Populations Endowed with a Synthetic Toggle Switch via Adaptive Pulsatile Feedback Control.

The problem of controlling cells endowed with a genetic toggle switch has been recently highlighted as a benchmark problem in synthetic biology. It has been shown that a carefully selected periodic forcing can balance a population of such cells in an undifferentiated state. The effectiveness of these control strategies, however, can be hindered by the presence of stochastic perturbations and uncertainties typically observed in biological systems and is therefore not robust. Here, we propose the use of feedback control strategies to enhance robustness and performance of the balancing action by selecting in real-time both the amplitude and the duty-cycle of the pulsatile inputs affecting the toggle switch behavior. We show, viain silico experiments and realistic agent-based simulations, the effectiveness of the proposed strategies even in the presence of uncertainties, stochastic effects, cell growth, and inducer diffusion. In so doing, we confirm previous observations made in the literature about coherence of the population when pulsatile forcing inputs are used, but, contrary to what was proposed in the past, we leverage feedback control techniques to endow the balancing strategy with unprecedented robustness and stability properties. We compare viain silico experiments different external control solutions and show their advantages and limitations from an in vivo implementation viewpoint.

Intrapleural paclitaxel for malignant pleural effusion from ovarian and breast cancer: a phase II study with pharmacokinetic analysis.

INTRODUCTION: Malignant pleural effusion (MPE) is a frequent complication in many types of tumors diminishing the patient's ability to perform activities. Despite various studies on talc treatment, some doubts about its safety and effectiveness remain, so the search for a more ideal intrapleural agent continues. We analyzed the effectiveness and safety of intrapleural paclitaxel in ovarian and breast cancer patients. PATIENTS AND METHODS: The primary endpoint was overall response rate (ORR); secondary objectives included time to progression (TTP), overall survival (OS) and safety of intrapleural paclitaxel. Pharmacokinetics of the drug was also analyzed. After drainage of pleural effusion and lung re-expansion, paclitaxel 120 mg/m(2) diluted in normal saline was infused through a preinserted catheter which was immediately closed and reopened 24 h later. Blood and pleural fluid samples were collected 1, 4 and 24 h after the end of paclitaxel instillation. When MPE was less than 200 ml/24 h the catheter was removed. Chest radiographs were performed at the beginning of intrapleural paclitaxel, at 1 and 2 months later or with clinical deterioration. RESULTS: We enrolled 18 patients with recurrent MPE: 11 with ovarian cancer and 7 with breast cancer. ORR was 77.8% at 1 month and 88.8%. at 2 months. Median TTP was 5.5 months (CI 95% 0.9-10.1) and median OS was 8.9 months (CI 95% 0.1-17.6). Patients achieving a complete response obtained a statistically significant longer survival than did patients with partial response or progressive disease. Chest pain, fever, and dyspnea were the most frequent side effects. Intrapleural paclitaxel concentrations were very high (mean ± SD = 478 ± 187 mg/l) and declined slowly (mean 24 h reduction ~30%). Detectable but low taxol plasma levels were found in most patients (mean ± SD = 0.045 ± 0.073 mg/l). CONCLUSION: Intrapleural paclitaxel is a safe and effective palliative treatment for MPE from breast and ovarian cancers and may be integrated with systemic chemotherapy.

Acute aortic syndromes: Role of multi-detector row CT.

Acute thoracic aortic syndromes encompass a spectrum of emergencies including aortic dissection, intramural haematoma, penetrating atherosclerotic ulcer and aneurysm rupture. All these life-threatening conditions require prompt diagnosis and appropriate management. To date multi-detector row Computed Tomography represents a valuable diagnostic tool especially in the emergency setting. This paper focus on the use of multi-detector row Computed Tomography in the evaluation of acute thoracic aortic syndromes and illustrates the key imaging findings related to each disease.

[Diaphragmatic herniation after oesophagectomy: a report of two cases]. / Ernia transdiaframmatica dopo esofagectomia. Presentazione di 2 casi.

Diaphragmatic herniation is the protrusion of abdominal structures into the chest through a defect in the diaphragm. It is a rare complication following oesophagectomy. Preoperative diagnosis is important in order to establish both the nature and extent of the diaphragmatic defect. The treatment of choice is surgery. In a series of 574 intrathoracic oesophagogastroplasties performed at our Institution from 1990 to 2004, the prevalence of diaphragmatic herniation was 0.35%. We report two cases of major diaphragmatic herniation after oesophagectomy for cancer performed using a laparotomic-thoracotomic (case 1) and a laparoscopicthoracotomic approach (case 2). The case 1 patient was asymptomatic: hernia repair involved hiatoplasty and mesh positioning. The case 2 patient presented with vomiting and abdominal pain: she underwent emergency laparoscopic surgery and direct closure of the diaphragmatic tear. At 12 months' follow-up, both patients were symptom-free. A barium swallow confirmed that the previously herniated abdominal viscera had returned to the abdomen. Diaphragmatic herniation following oesophagectomy is a rare complication which may be asymptomatic or present as bowel obstruction. Several aetiopathogenetic factors may be responsible for diaphragmatic hernias: enlargement of the diaphragmatic hiatus, a combination of negative pressure in the chest and positive pressure in the abdomen, and small number of adhesions in the case of patients operated on with minimally invasive surgery. Surgical repair is the treatment of choice and is mandatory as emergency treatment in the case of symptomatic hernias.

Long-term survival of patients treated with photodynamic therapy for carcinoma in situ and early non-small-cell lung carcinoma.

PURPOSE: The role of photodynamic therapy (PDT) in the treatment of small cancers has been established in several clinical studies. Here, we report on the efficacy of PDT for early inoperable or recurrent non-small-cell lung cancer (NSCLC). METHODS AND MATERIALS: From June 1989 to November 2004, 40 patients with 50 NSCLC were treated with PDT. Twelve cases were inoperable for medical reasons and were staged as T1N0M0, and 28 had recurrent in situ carcinoma. Patients with residual disease after PDT received definitive radiotherapy and/or brachytherapy. Follow-up ranged from 6 to 167 months (median 43.59). Twenty of the 40 patients received i.v. injections of hematoporphyrin derivative (5 mg/kg), the other 20 had injections of porfimer sodium (Photofrin, 2 mg/kg). An argon dye laser (630 nm wavelength, 200-300 J/cm2) was used for light irradiation in 24 of the 40 patients, a diode laser (Diomed, 630 nm wavelength, 100-200 J/cm2) in the other 16. RESULTS: PDT obtained a 72% complete response (CR) rate (36/50 treated lesions), that is 27 CR among the 37 Tis carcinomas and 9 among the 13 T1 cases. Kaplan-Meier curves showed a mean overall survival (OS) of 75.59 months (median 91.4 months). Two- and 5-year OS rates were 72.78% and 59.55%. The mean and median survival rates for patients with Tis stage were 86.5 and 120.4 months, respectively (standard error 9.50) and for patients with T1 disease they were 45.78 and 35.71 months, respectively; the difference was statistically significant (P = 0.03). No severe early or late PDT-related adverse events were recorded. CONCLUSIONS: PDT is effective in early primary or recurrent NSCLC, resulting in a CR rate of 72%. The incorporation of PDT in standard clinical practice, in combination with radiotherapy, warrants further investigation.

Primary mediastinal large B-cell lymphoma: results of intensive chemotherapy regimens (MACOP-B/VACOP-B) plus involved field radiotherapy on 53 patients. A single institution experience.

PURPOSE: The optimal therapy for primary mediastinal large B-cell lymphoma (PMLBCL) remains undefined. The superiority of intensive chemotherapy regimens (Methotrexate, Doxorubicin, Cyclophosphamide, Vincristine, Prednisone, Bleomycin [MACOP-B]/Etoposide, Doxorubicin, Cyclophosphamide, Vincristine, Prednisone, Bleomycin [VACOP-B]) over Cyclophosphamide, Doxorubicin, Vincristine, Prednisone (CHOP)-like chemotherapy is upheld by some authors. The role of radiotherapy is still debated. In the absence of randomized trials, we report clinical findings and treatment response in 53 consecutive patients treated with intensive chemotherapy and mediastinal involved-field radiation therapy (IFRT). METHODS AND MATERIAL: Fifty-three consecutive patients with PMLBCL were retrospectively analyzed. Planned treatment consisted of induction chemotherapy (I-CT; Prednisone, Methotrexate, Doxorubicin, Cyclophosphamide, Etoposide-Mechloroethamine, Vincristine, Procarbazine, Prednisone [ProMACE-MOPP] in the first 2 patients, MACOP-B in the next 11, and VACOP-B in the last 40) followed by IFRT. Planned treatment was concluded in 43 of 53 patients; in 10 patients, I-CT was not immediately followed by IFRT. Among these 10 patients, 6 received high-dose chemotherapy (HD-CT) followed by IFRT, 2 received HD-CT, and 2 received no further treatment. RESULTS: After a median follow-up of 93.9 months (range, 6-195 months), 45 of 53 patients (84.9%) were alive without disease. Eight patients died: 7 of PMLBCL and 1 of toxicity during HD-CT. The 5-year disease-free survival (DFS) and overall survival rates were 93.42% and 86.6%, respectively. The response rates after I-CT were complete response (CR) in 20 (37.73%) and partial response (PR) in 30 (56.60%); 3 patients (5.66%) were considered nonresponders. Among patients in PR after chemotherapy, 92% obtained a CR after IFRT. CONCLUSIONS: Our report confirms the efficacy of intensive chemotherapy plus mediastinal IFRT. IFRT plays a pivotal role in inducing CR in patients in PR after chemotherapy.

Treatment of chemotherapy-induced oral mucositis with light-emitting diode.

OBJECTIVE: The aim of this study was to assess the clinical effectiveness of phototherapy with noncoherent light in the alleviation of chemotherapy-induced mucositis in patients with metastatic cancer. BACKGROUND DATA: Mucositis occurs in more than 40% of chemotherapy-treated patients, significantly reducing the quality of their lives. Many different interventions have been evaluated to reduce oral mucositis. Recently, good results have been achieved by phototherapy with photoradiation, a technique which has virtually no side effects. Some clinical results seem to indicate that also phototherapy through noncoherent light emissions which can be produced by less expensive light sources such as light-emitting diodes (LEDs) may be effective. However, until now, no studies have been available on this subject. METHODS: Twelve patients, aged from 34 to 82, selected on the basis of a diagnosis of chemotherapy-induced oral mucositis, were treated intra-orally through a noncoherent LED emission, wavelength 645 +/- 15 nm, 7.8 mW, fluence 0.99 J/cm(2), three times a day for 1 week. Mucositis was scored daily using the Daily Mucositis Index (DMI), a scale that evaluates the disease evolution through 16 different items. The primary end-point assessed was the time to recovery, from the start of LED treatment, compared to a nonrandomized control group of 12 patients with comparable stomatitis. RESULTS: The median healing time, expressed as the DMI decrease, was 1.7 (range 1-2.8) and, in seven LED-treated patients, was shorter than in the control group. The healing rate (measured as the ratio of the DMIs) increased from 117% to 164%. CONCLUSION: This pilot study shows that LED treatment is safe and capable of reducing the duration of chemotherapy-induced mucositis. This result needs to be confirmed in an adequate phase III study.

An ectopic mediastinal parathyroid adenoma accurately located by a single-day imaging protocol of Tc-99m pertechnetate-MIBI subtraction scintigraphy and MIBI-SPECT-computed tomographic image fusion.

PURPOSE: Because ectopic parathyroid adenoma (PA) is a frequent cause of failed initial surgery, an imaging approach with accurate preoperative localization is recommended by some authors in patients with primary hyperparathyroidism (HPT). METHODS: The authors describe a 52-year-old woman in whom primary HPT was diagnosed incidentally during a screening program for osteoporosis. The peculiarity of this case is that the patient was examined before operation in a single-day multimodal imaging protocol based on the combination of high-resolution cervical ultrasound, planar Tc-99m pertechnetate-MIBI scans, and an MIBI-SPECT-computed tomographic (CT) image fusion study. An ectopic PA was accurately located in the upper middle mediastinum, close to the lower margin of the sternal notch. RESULTS: Guided by the MIBI-SPECT-CT fusion images, the surgeon performed a limited median sternotomy and easily removed the PA that was revealed before operation. To confirm the completeness of resection, a bilateral neck exploration was performed through the same incision, with identification of three normally sized parathyroid glands. CONCLUSIONS: Our experience suggests the utility of multimodality imaging procedures for the accurate preoperative localization of PAs, particularly when they are present in ectopic mediastinal locations. Such procedures, including the MIBI-SPECT-CT image fusion study, can be performed in a single day.