Energetic Valorisation of Saltworks Bitterns via Reverse Electrodialysis: A Laboratory Experimental Campaign

Concentrated bitterns discharged from saltworks have extremely high salinity, often up to 300 g/L, thus their direct disposal not only has a harmful effect on the environment, but also generates a depletion of a potential resource of renewable energy. Here, reverse electrodialysis (RED), an emerging electrochemical membrane process, is proposed to capture and convert the salinity gradient power (SGP) intrinsically conveyed by these bitterns also aiming at the reduction of concentrated salty water disposal. A laboratory-scale RED unit has been adopted to study the SGP potential of such brines, testing ion exchange membranes from different suppliers and under different operating conditions. Membranes supplied by Fujifilm, Fumatech, and Suez were tested, and the results were compared. The unit was fed with synthetic hypersaline solution mimicking the concentration of natural bitterns (5 mol/L of NaCl) on one side, and with variable concentration of NaCl dilute solutions (0.01-0.1 mol/L) on the other. The influence of several operating parameters has also been assessed, including solutions flowrate and temperature. Increasing feed solutions' temperature and velocity has been found to lower the stack resistance, which enhances the output performance of the RED stack. The maximum obtained power density (corrected to account for the effect of electrodic compartments, which can be very relevant in five cell pairs laboratory stacks) reached around 10.5 W/m²_cellpair, with FUJIFILM Type 10 membranes, temperature of 40 °C, and a fluid velocity of 3 cm s^-1 (as empty channel, considering 270 μm thickness). Notably, the present study results confirm the large potential for SGP generation from hypersaline brines, thus providing useful guidance for the harvesting of SGP in seawater saltworks all around the world.

Mining minerals and critical raw materials from bittern: Understanding metal ions fate in saltwork ponds

Seawater represents a potential resource for raw materials extraction. Although NaCl is the most representative mineral extracted other valuable compounds such as Mg, Li, Sr, Rb and B and elements at trace level (Cs, Co, In, Sc, Ga and Ge) are also contained in this "liquid mine". Most of them are considered as Critical Raw Materials by the European Union. Solar saltworks, providing concentration factors of up-to 20 to 40, offer a perfect platform for the development of minerals and metal recovery schemes taking benefit of the concentration and purification achieved along the evaporation saltwork ponds. However, the geochemistry of these elements in this environment has not been yet thoroughly evaluated. Their knowledge could enable the deployment of technologies capable to achieve the recovery of valuable minerals. The high ionic strengths expected (0.5-7 mol/kg) and the chemical complexity of the solutions imply that only numerical geochemical codes, as PHREEQC, and the use of Pitzer model to estimate the activity coefficients of the different species in solution can be adopted to provide valuable description of the systems. In the present work, for the first time, PHREEQC Pitzer code database was extended to include the target minor and trace elements using Trapani saltworks (Sicily, Italy) as a case study system. The model was able to predict: i) the purity in halite and the major impurities contained, mainly Ca, Mg and sulphate species; ii) the fate of minor components as B, Sr, Cs, Co, Ge and Ga along the evaporation ponds. The results obtained pose a fundamental step in critical raw materials mining from seawater brine, for process intensification and combination with desalination.

Influence of Operational Strategies for the Recovery of Magnesium Hydroxide from Brines at a Pilot Scale

The continuous depletion of minerals caused by land mining and the increase in their demand have pushed the development of novel sustainable technological processes for mineral recovery from unconventional sources. In this context, magnesium (Mg) has gained considerable attention for its peculiar properties and high relevance of its compounds, such as magnesium hydroxide, Mg(OH)₂. In the present work, the influence of several operating conditions on the Mg(OH)₂ precipitation process was thoroughly investigated by adopting a novel multiple feed-plug flow reactor. The influence of (i) initial Mg²⁺ concentrations in the feed stream; (ii) brine and alkaline flow rates; and (iii) the product recycling strategy (seeded crystallization) was considered. The results marked the possibility of improving sedimentation and filterability properties of Mg(OH)₂ suspensions by adopting the recycling strategy to overcome industrial issues associated with the production of Mg(OH)₂ suspensions using NaOH solutions.

A Computational Study on Temperature Variations in MRgFUS Treatments Using PRF Thermometry Techniques and Optical Probes

Structural and metabolic imaging are fundamental for diagnosis, treatment and follow-up in oncology. Beyond the well-established diagnostic imaging applications, ultrasounds are currently emerging in the clinical practice as a noninvasive technology for therapy. Indeed, the sound waves can be used to increase the temperature inside the target solid tumors, leading to apoptosis or necrosis of neoplastic tissues. The Magnetic resonance-guided focused ultrasound surgery (MRgFUS) technology represents a valid application of this ultrasound property, mainly used in oncology and neurology. In this paper; patient safety during MRgFUS treatments was investigated by a series of experiments in a tissue-mimicking phantom and performing ex vivo skin samples, to promptly identify unwanted temperature rises. The acquired MR images, used to evaluate the temperature in the treated areas, were analyzed to compare classical proton resonance frequency (PRF) shift techniques and referenceless thermometry methods to accurately assess the temperature variations. We exploited radial basis function (RBF) neural networks for referenceless thermometry and compared the results against interferometric optical fiber measurements. The experimental measurements were obtained using a set of interferometric optical fibers aimed at quantifying temperature variations directly in the sonication areas. The temperature increases during the treatment were not accurately detected by MRI-based referenceless thermometry methods, and more sensitive measurement systems, such as optical fibers, would be required. In-depth studies about these aspects are needed to monitor temperature and improve safety during MRgFUS treatments.

The effect of inactivated Lactobacillus LB fermented culture medium on symptom severity: observational investigation in 297 patients with diarrhea-predominant irritable bowel syndrome

INTRODUCTION

Little is known about the intensity of symptoms of diarrhea-predominant IBS (IBS-D) or the consequences of the disease on patients' health-related quality of life (HRQOL). This observational investigation assessed the symptoms (abdominal pain, bloating, number of stools per day, and stool consistency), impact on HRQOL, and consequence on anal continence in 297 patients with IBS-D before and after 1 month of probiotic treatment with Lacteol (inactivated Lactobacillus LB plus fermented culture medium).

METHODS

Functional assessment using a standardized visual analogue scale in order to quantify abdominal pain, bloating, and quality of life before and after 1 month of treatment with 2 capsules/day of Lacteol. The number of symptomatic days per week, number of stools, consistency of stools, secondary fecal incontinence rate, and potential trigger effect of food were quantified. A χ2 test was used to compare qualitative data and the variance of quantitative criteria was analyzed.

RESULTS

The pain score decreased from 4.46±0.15 on a scale of 0-10 before treatment to 2.8±0.14 after treatment (p<0.0001). Bloating decreased from 4.49±0.18 to 2.5±0.15 on a scale of 0-10 (p<0.0001). The HRQOL score, which is inversely correlated with quality of life, decreased from 5.99±0.14 to 3.92±0.16 (p<0.0001). In this cohort study, the fecal incontinence rate secondary to diarrhea was clearly higher than that of the general population: 18% versus a prevalence of 9-10%, according to different studies. The mean number of stools per week decreased from 17.59 to 12.83 after treatment (p<0.0001). Before treatment, 54% of patients had watery stools and 46% had smooth stools; at the end of treatment, only 18.5% of patients still had watery stools, and 34% had normal stools. 52% of patients attributed their symptoms to their diet: 34% to vegetables, 29% to fruit, 15% to milk, 15% to fat, 6% to peppers and spices, and 4% to sugar.

CONCLUSION

This observational investigation shed new light on patients with IBS-D, the HRQOL of which is altered by a fecal incontinence rate twice as high as that of the general population. Correlation with diet is confirmed by 1 out of 2 patients reporting poor tolerance of fiber and dairy products. Nutritional management should thus be part of these patients' treatment. Inactivated Lactobacillus LB plus fermented culture medium is a probiotic drug that has been used by physicians for a long time to treat patients with diarrhea. Strongly concentrated, it has no side effects and seems to help these patients. Due to a strong placebo effect in patients with this pathology, however, a controlled study is necessary to confirm this result.

Ribavirin and interferon-alpha combination therapy vs interferon-alpha alone in the retreatment of chronic hepatitis C: a randomized clinical trial

Interferon-alpha (IFN-alpha) induces sustained remission of chronic hepatitis C in approximately 25% of patients. In patients who are non-responders to the first course of therapy, retreatment with IFN-alpha is of limited efficacy. Ribavirin has also been used to treat chronic hepatitis C, but it induces only a transient response. In this study, we evaluated the efficacy of ribavirin and IFN-alpha combination therapy for IFN-alpha resistant chronic hepatitis C. Twenty-four IFN-alpha non-responders and 24 relapsers were randomized to receive either ribavirin (1000 mg per day) together with IFN-alpha (3-6 million units (MU) thrice weekly) or the same dose of IFN-alpha alone, for 6 months. Both at the end of treatment and 6 months later, normal transaminase levels were more common in the patients receiving combination therapy than in the group receiving IFN-alpha alone: 17 (70.8%) vs seven (29.2%) patients (P = 0.009) and six (25%) vs one (4.2%) patient (P = 0.034), respectively. At the end of treatment and 6 months later, serum HCV RNA was no longer detectable in eight (33.3%) and five (20.8%) patients in the combination therapy group and in six (25%) and one (4.2%) patient in the IFN-alpha therapy group, respectively. Three patients (12.5%) were withdrawn prematurely from combination therapy because of side-effects; ribavirin therapy was ceased or dosage reduced in six other patients (25%), again because of side-effects. In conclusion, this combination treatment was more effective than retreatment with IFN-alpha, alone, in inducing sustained biochemical remission of chronic hepatitis C that was resistant to a previous course of IFN-alpha. The combination treatment, however, was frequently associated with significant side-effects.

Comparative study of sucralfate versus cimetidine in the treatment of acute gastroduodenal ulcer. Randomized trial with 667 patients

Six-hundred sixty-seven patients with endoscopically proven peptic ulcer were included in a randomized, multicenter trial to assess the comparative efficacy of sucralfate and cimetidine. One hundred eighty-seven patients with gastric ulcer and 480 patients with duodenal ulcer completed the study. Ulcer healing was evaluated endoscopically at six weeks for duodenal ulcer and at eight weeks for gastric ulcer. Patients with unhealed ulcer at this time were assigned to the other therapy for a second period of six or eight weeks of treatment (crossover). In patients with duodenal gastric ulcer, pain relief and healing were not significantly different in the two groups. Eighty-eight percent of duodenal ulcers and 73 percent of gastric ulcers healed with six weeks of sucralfate treatment. Reported side effects and symptoms, pooled together for duodenal and gastric ulcer, were more significant in the sucralfate group (7.5 percent) than in the cimetidine group (3.7 percent). Constipation was the most frequent symptom recorded. In conclusion, sucralfate and cimetidine are both excellent healing agents for short-term treatment of duodenal and gastric ulcer. Both give rapid relief of symptoms without severe side effects.

[Comparative study of intravenous midazolam and diazepam used as sedative agents during gastroscopy]

Midazolam was compared with diazepam for the intravenous sedation of gastroscopy patients. 0.1 mg X kg-1 midazolam were given to patients less than 65 years old, and 0.085 mg X kg-1 after that age; diazepam doses were 0,2 mg X kg-1 and 0.15 mg X kg-1 respectively. The effect and duration of action of both drugs were similar. The main differences between them were as follows: the intravenous injection of midazolam was not painful, and virtually no venous complications were seen; amnesia and patient contentedness were more frequent with midazolam; gastric secretion was reduced with midazolam. Neither drug had clinically significant cardiovascular effects.

[Contribution of per- and trans-endoscopic pH measurements to the exploration of the upper digestive tract (author's transl)]

Per- and trans-endoscopic pH measurements in the upper digestive tract have provided new and interesting data. Performed by the authors on a series of 314 patients, they showed that the gastric pH is seldom acid, even in duodenal ulcer, and is always alkaline in gastric ulcer and gastric carcinoma. Gastritis may be divided into two groups, depending on whether the pH is normal or hypoacid (4.5 in the antrum, 2.5 in the fundus). Biopsies demonstrated the presence of intestinal metaplasia and epithelial dysplasia in 57.8% of 83 patients with hypoacid gastritis. The method therefore constitutes a simple and reliable means of determining markers of precancerous lesions.

[Islet cell tumor with diarrhea and diabetes (glucagonoma?) associated with hyperparathyroidism. Long-term results of local-regional treatment with streptozotocin]

A case report of endocrine pancreatic tumour associated with diabetes and hyperparathyroidism is presented. Some arguments are in favour of a glucagonoma. Despite the absence of beta-cells in tumour, an exceptional result was obtained by use of Streptozotocin. This case brings up the relations between endocrine pancreatic tumours and parathyroid, and may be included in polyglandular adenoma syndrome.