Geochemical considerations for Hot, Dry Rock Systems

Circulating systems intended to model the P-T conditions found in the natural HDR (Hot Dry Rock) geothermal system at Los Alamos have been built. Experiments with these systems have determined the following parameters for the ''down hole'' reservoir: sample weight loss, circulating solution composition, textural changes in the rock, mineral loss from the rock and effects of chemical additives on rock erosion. The analyses of solutions generated from rock-water interactions in the experimental systems show the extremely dilute nature of the working fluid. These solutions are not brines. Silica scaling in the surface heat exchanger was found to account for the difference between loss of sample rate and analyzed silica in the solution. The weight loss data indicate that there was continuous transport of silica from the ''down hole'' rock to the heat exchanger. Experiments contrasting felsic and mafic rocks in the HDR concept indicate that a reservoir consisting of glass bearing basaltic rock would tend to produce greater scaling problems than systems emplaced in granite. Experimental results suggest that Na{sub 2}CO{sub 3} solutions may provide a means of increasing permeability and thereby increasing the effective heat transfer area of the reservoir. A brief description is given of a small test loop for simulating the flow of a geothermal solution through a heat exchanger. This loop, which is being built, will be used to study the coagulation and precipitation of silica under conditions similar to those expected in the field

Books in Arabic Script

The chapter approaches the book in Arabic script as the indispensable means for the transmission of knowledge across Eurasia and Africa, within cultures and across cultural boundaries, since the seventh century ad. The state of research can be divided into manuscript and print studies, but there is not yet a history of the book in Arabic script that captures its plurilinear development for over fourteen hundred years. The chapter explores the conceptual and practical challenges that impede the integration of the book in Arabic script into book history at large and includes an extensive reference list that reflects its diversity. The final published version was slightly updated, and includes seven illustrations of six Qurans from the holdings of Columbia University Libraries, four manuscripts and two printed versions. Moreover, the illustrations are images of historical artifacts which are in the public domain - despite Wiley's copyright claim

Early post-liver transplant use of direct-acting antivirals in naive and NS5A inhibitor-experienced HCV patients

Direct-acting antiviral drugs (DAA) are safe and effective in the HCV population. However, in patients with decompensated cirrhosis and/or active hepatocellular carcinoma or relapse to NS5A inhibitors, response rates are lower and DAA therapy must be postponed until after liver transplant in an era of organ shortage and suboptimal donors. We aimed to assess the prevalence of patients still HCV infected at time of transplantation over the last 3 years in our Center and describe the safety and efficacy of DAA therapy started as soon as possible after surgery. We enrolled all HCV viraemic patients transplanted in our Centre from January 2019 to March 2022. The follow-up was closed in July 2022. Among 490 liver transplants, 49 (10%) patients were still HCV viraemic at operation, 43 naive to DAA and 6 were NS5A-experienced. Median donor age was 64 years; donor risk index was 1.8. In naive patients, sofosbuvir/velpatasvir was started after a median time of 1 day from surgery, while in NS5A-experienced sofosbuvir/velpatasvir/voxilaprevir after 14.5 days (p =.001). Response rate was 98%. 1 NS5A-experienced patient experienced acute cholestatic hepatitis which promptly reverted after permanent DAA discontinuation. Hence, very early post-liver transplant HCV eradication was safe and effective thanks to a close teamwork which involved anaesthesiologists, transplant surgeons and hepatologists

Apparent life-threatening events: Helping infants help themselves

Objectives Apparent life-threatening event (ALTE) refers to a constellation of unexpected events suddenly occurring in infants that extremely alarm the observers. The objectives of this study were to evaluate 1) intervention of Emergency Service (ES) at home, 2) parental behavior before ES intervention, 3) patients' outcome at follow-up of a minimum of 6 months. Methods Retrospective study of infants younger than 12 months whose parents called ES and were evaluated for ALTE from 2005 to 2014. Tactile stimulation (TS) was defined as any maneuver performed by parents or ES staff aimed at rescuing patients without cardiopulmonary resuscitation attempts. Cardiopulmonary resuscitation was defined according to American Heart Association Guidelines 2010. Results One hundred eighty-eight patients were eligible. Emergency Service provided intervention for 178 infants (10 were assisted only by phone). All patients received TS by parents before ES arrival. Mean time for ES to reach patient location was 15 ± 10 minutes. On examination, 136 patients (76.5%) seemed normal and 42 symptomatic. One hundred sixty-three patients were brought to the emergency department where 23 patients were found symptomatic. One hundred six of 163 patients underwent capillary blood gas determination and, in 28 (26%) of 106, alterations were found. No infant had subsequent cardiopulmonary arrest or clinically evident adverse neurological outcome. Six were found to be epileptic. No infant died during the episode or during follow-up. Conclusions Our findings suggest that ALTE is an alarming but self-limiting phenomenon that can be resolved either spontaneously or by simple TS in most cases. Emergency Service should solicit patients' physiological responses through TS first while considering a cardiopulmonary resuscitation maneuver