Light Dark Matter Search with a High-Resolution Athermal Phonon Detector Operated above Ground.

We present limits on spin-independent dark matter-nucleon interactions using a 10.6 g Si athermal phonon detector with a baseline energy resolution of σ_{E}=3.86±0.04(stat)_{-0.00}^{+0.19}(syst) eV. This exclusion analysis sets the most stringent dark matter-nucleon scattering cross-section limits achieved by a cryogenic detector for dark matter particle masses from 93 to 140 MeV/c^{2}, with a raw exposure of 9.9 g d acquired at an above-ground facility. This work illustrates the scientific potential of detectors with athermal phonon sensors with eV-scale energy resolution for future dark matter searches.

Constraints on Lightly Ionizing Particles from CDMSlite.

The Cryogenic Dark Matter Search low ionization threshold experiment (CDMSlite) achieved efficient detection of very small recoil energies in its germanium target, resulting in sensitivity to lightly ionizing particles (LIPs) in a previously unexplored region of charge, mass, and velocity parameter space. We report first direct-detection limits calculated using the optimum interval method on the vertical intensity of cosmogenically produced LIPs with an electric charge smaller than e/(3×10^{5}), as well as the strongest limits for charge ≤e/160, with a minimum vertical intensity of 1.36×10^{-7} cm^{-2} s^{-1} sr^{-1} at charge e/160. These results apply over a wide range of LIP masses (5 MeV/c^{2} to 100 TeV/c^{2}) and cover a wide range of ßγ values (0.1-10^{6}), thus excluding nonrelativistic LIPs with ßγ as small as 0.1 for the first time.

Erratum: First Dark Matter Constraints from a SuperCDMS Single-Charge Sensitive Detector [Phys. Rev. Lett. 121, 051301 (2018)].

This corrects the article DOI: 10.1103/PhysRevLett.121.051301.

Results from the Super Cryogenic Dark Matter Search Experiment at Soudan.

We report the result of a blinded search for weakly interacting massive particles (WIMPs) using the majority of the SuperCDMS Soudan data set. With an exposure of 1690 kg d, a single candidate event is observed, consistent with expected backgrounds. This analysis (combined with previous Ge results) sets an upper limit on the spin-independent WIMP-nucleon cross section of 1.4×10^{-44} (1.0×10^{-44}) cm^{2} at 46 GeV/c^{2}. These results set the strongest limits for WIMP-germanium-nucleus interactions for masses >12 GeV/c^{2}.

First Dark Matter Constraints from a SuperCDMS Single-Charge Sensitive Detector.

We present the first limits on inelastic electron-scattering dark matter and dark photon absorption using a prototype SuperCDMS detector having a charge resolution of 0.1 electron-hole pairs (CDMS HVeV, a 0.93 g CDMS high-voltage device). These electron-recoil limits significantly improve experimental constraints on dark matter particles with masses as low as 1 MeV/c^{2}. We demonstrate a sensitivity to dark photons competitive with other leading approaches but using substantially less exposure (0.49 g d). These results demonstrate the scientific potential of phonon-mediated semiconductor detectors that are sensitive to single electronic excitations.

New Results from the Search for Low-Mass Weakly Interacting Massive Particles with the CDMS Low Ionization Threshold Experiment.

The CDMS low ionization threshold experiment (CDMSlite) uses cryogenic germanium detectors operated at a relatively high bias voltage to amplify the phonon signal in the search for weakly interacting massive particles (WIMPs). Results are presented from the second CDMSlite run with an exposure of 70 kg day, which reached an energy threshold for electron recoils as low as 56 eV. A fiducialization cut reduces backgrounds below those previously reported by CDMSlite. New parameter space for the WIMP-nucleon spin-independent cross section is excluded for WIMP masses between 1.6 and 5.5 GeV/c^{2}.

First direct limits on lightly ionizing particles with electric charge less than e/6.

While the standard model of particle physics does not include free particles with fractional charge, experimental searches have not ruled out their existence. We report results from the Cryogenic Dark Matter Search (CDMS II) experiment that give the first direct-detection limits for cosmogenically produced relativistic particles with electric charge lower than e/6. A search for tracks in the six stacked detectors of each of two of the CDMS II towers finds no candidates, thereby excluding new parameter space for particles with electric charges between e/6 and e/200.

Search for low-mass weakly interacting massive particles using voltage-assisted calorimetric ionization detection in the SuperCDMS experiment.

SuperCDMS is an experiment designed to directly detect weakly interacting massive particles (WIMPs), a favored candidate for dark matter ubiquitous in the Universe. In this Letter, we present WIMP-search results using a calorimetric technique we call CDMSlite, which relies on voltage-assisted Luke-Neganov amplification of the ionization energy deposited by particle interactions. The data were collected with a single 0.6 kg germanium detector running for ten live days at the Soudan Underground Laboratory. A low energy threshold of 170 eVee (electron equivalent) was obtained, which allows us to constrain new WIMP-nucleon spin-independent parameter space for WIMP masses below 6 GeV/c2.

Search for low-mass weakly interacting massive particles with SuperCDMS.

We report a first search for weakly interacting massive particles (WIMPs) using the background rejection capabilities of SuperCDMS. An exposure of 577 kg days was analyzed for WIMPs with mass <30 GeV/c(2), with the signal region blinded. Eleven events were observed after unblinding. We set an upper limit on the spin-independent WIMP-nucleon cross section of 1.2×10(-42) cm(2) at 8 GeV/c(2). This result is in tension with WIMP interpretations of recent experiments and probes new parameter space for WIMP-nucleon scattering for WIMP masses <6 GeV/c(2).

Telephone assessment of new hernia referrals-is it possible?

PURPOSE: Utilisation of remote clinics is increasing in healthcare settings worldwide. During the height of the COVID pandemic, our UK-based teaching hospital has trialled telephone assessment for new patients presenting with primary hernias. Selected cases are listed for elective repair of primary hernia direct from telephone clinic assessment. In March 2021, after this process had been in place for 13 months, departmental triage criteria were introduced, allocating patients to initial assessment in Face to Face or Telephone Clinics. Here, we evaluate the effectiveness of telephone assessment, with specific attention to 'Day of Surgery' cancellation. We also assess the effect of our triage criteria on rate of 'Day of Surgery' cancellation. METHODS: Departmental diaries were studied retrospectively to identify patients listed for hernia repair between February 2020 and February 2022. Data were obtained from clinic letters, discharge paperwork and operating lists, as well as from management teams. Fishers Exact test was used to compare groups seen either face to face or remotely as well and pre- and post-intervention. RESULTS: 325 patients were listed for hernia repair, 56 after telephone assessment. 6 (11%) of those listed from telephone clinic were cancelled on the day of surgery, compared with 34 (13%) of those seen face to face. With triage criteria in place, listing from telephone clinic increased significantly from 14 to 27%. Overall day of surgery cancellations reduced from 13 to 9%. Rate of day of surgery cancellation in those assessed in telephone clinic reduced from 12 to 9%. CONCLUSIONS: There is no significant difference between day of surgery cancellations after face to face or telephone clinic assessment. Triage criteria for telephone assessment appear to increase the numbers being listed after remote clinics. This did not significantly impact the number of day of surgery cancellations.

Pancreatoduodenectomy for suspected malignancy: nonmalignant histology confers increased risk of serious morbidity.

BACKGROUND/AIMS: A tissue diagnosis is not always obtained prior to pancreatoduodenectomy (PD) and a proportion of patients are found to have noncancerous histology postoperatively. It is unknown if these patients have different outcomes when compared with those who have malignancy confirmed. METHODS: A retrospective paired case matched control study was undertaken. Patients who underwent PD for suspected malignancy but ultimately had nonmalignant histology were identified. Each was matched to a confirmed malignant control using the following criteria: age, gender, body mass index, American Society of Anesthesiologists grade, neoadjuvant treatment, preoperative serum bilirubin, preoperative biliary stenting and type of pancreatic anastomosis. Matching was blinded to the measured outcomes, which included perioperative morbidity and mortality. RESULTS: Forty-five cases were compared with 45 well-matched controls. There was no difference in 30- or 90-day mortality, or length of stay. While overall morbidity rates were the same, patients with nonmalignant disease were more likely to experience major (Clavien-Dindo grade III-IV) morbidity (40.0% versus 17.8%, p = 0.0352). Independently, rates of clinically relevant pancreatic fistula (CR-POPF) were higher in the nonmalignant group (22.2% versus 4.44%, p = 0.0131). CONCLUSIONS: In our study, PD patients with nonmalignant histology had significantly higher incidence of major morbidity and CR-POPF when compared with those who had malignancy confirmed. This should be considered when planning the management of patients with known or presumed benign/premalignant disease.

Intention to Treat Laparoscopic Versus Open Hemi-Hepatectomy: A Paired Case-Matched Comparison Study.

BACKGROUND: The benefits of laparoscopic hemi-hepatectomy compared to open hemi-hepatectomy are not clear. OBJECTIVE: This study aims to share our experience with the laparoscopic hemi-hepatectomy compared to an open approach. METHODS: A total of 40 consecutive laparoscopically started hemi-hepatectomy (intention-to-treat analysis) cases between August 2012 and October 2015 were matched against open cases using the following criteria: laterality of surgery and pathology (essential criteria); American Society of Anesthesiologists score, body mass index, pre-operative bilirubin, neo-adjuvant chemotherapy, additional procedures, portal vein embolization, and presence of cirrhosis/fibrosis on histology (secondary criteria); age and gender (tertiary criteria). Hand-assisted and extended hemi-hepatectomy cases were excluded from the study. The two groups were compared for blood loss, operative time, hospital stay, morbidity, mortality, and oncological outcomes. All complications were quantified using the Clavien-Dindo classification. RESULTS: Two groups were well matched (p = 1.00). In the two groups, 10 patients had left and 30 had right hemi-hepatectomy. Overall conversion rate was 15%. Median length of hospital and high dependency unit stay was less in the intention to treat laparoscopic hemi-hepatectomy group: 6 versus 8 days, p = 0.025 and 1 versus 2 days, p = 0.07. Median operative time was longer in the intention to treat laparoscopic hemi-hepatectomy group: 420 min (range: 389.5-480) versus 305 min (range: 238.8-348.8; p = 0.001). Intra-operative blood loss was equivalent, but the overall blood transfusions were higher in the intention to treat laparoscopic hemi-hepatectomy (50 vs 29 units, p = 0.36). The overall morbidity (18 vs 20 patients, p = 0.65), mortality (2.5%), and the positive resection margin status were similar (18% vs 21%, p = 0.76). The 1- (87.5% vs 92.5%, p = 0.71) and 3-year survival (70% vs 72.5%, p = 1.00) was also similar. CONCLUSIONS: We observed lower hospital and high dependency unit stay in the laparoscopic group. However, the laparoscopic approach was associated with longer operating time and a non-significant increase in blood transfusion requirements. There was no difference in morbidity, mortality, re-admission rate, and oncological outcomes.

Comparison of risk-scoring systems in the prediction of outcome after liver resection.

BACKGROUND: Risk prediction techniques commonly used in liver surgery include the American Society of Anesthesiologists (ASA) grading, Charlson Comorbidity Index (CCI) and cardiopulmonary exercise tests (CPET). This study compares the utility of these techniques along with the number of segments resected as predictive tools in liver surgery. METHODS: A review of a unit database of patients undergoing liver resection between February 2008 and January 2015 was undertaken. Patient demographics, ASA, CCI and CPET variables were recorded along with resection size. Clavien-Dindo grade III-V complications were used as a composite outcome in analyses. Association between predictive variables and outcome was assessed by univariate and multivariate techniques. RESULTS: One hundred and seventy-two resections in 168 patients were identified. Grade III-V complications occurred after 42 (24.4%) liver resections. In univariate analysis of CPET variables, ventilatory equivalents for CO2 (VEqCO2) was associated with outcome. CCI score, but not ASA grade, was also associated with outcome. In multivariate analysis, the odds ratio of developing grade III-V complications for incremental increases in VEqCO2, CCI and number of liver segments resected were 1.09, 1.49 and 2.94, respectively. CONCLUSIONS: Of the techniques evaluated, resection size provides the simplest and most discriminating predictor of significant complications following liver surgery.

An experimental technique to assess the immunologic consequences of segmental small bowel transplantation.

BACKGROUND: The amount of native small bowel required for adequate nutrition is variable, but lies between 10% and 20% of full length. Currently, for patients requiring small bowel transplantation (SBT), standard practice is to transplant the entire small bowel if space permits. Few experimental studies have addressed the effect of the length of small bowel transplanted on immune responses and in those that have, the amount of mesenteric lymph node (MLN) transplanted has always been a potential confounding factor, as have differences between jejunum and ileum. METHODS: Full-length and segmental heterotopic rat SBT was performed between PVG donor and DA recipients. To transplant reduced length small bowel grafts but to exclude immunologic differences between jejunum and ileum, equal lengths of bowel were resected from proximal and distal ends in the donor. A proportional amount of MLN was carefully dissected using a microvascular technique and then excised. Serial serum samples from the transplant recipients were tested for anti-PVG (rejection) and anti-DA (graft-versus-host) antibodies using a two-color flow cytometric technique, described previously, with the aim of looking for differences in immunologic responses to full and segmental grafts. RESULTS: We have established a model of segmental SBT that includes a proportional amount of MLN and is free from differences between jejunum and ileum. Preliminary data have demonstrated the development of circulating anti-host and anti-graft antibodies with time for both full-length and segmental SBT.

Perioperative analgesia in experimental small bowel transplantation.

BACKGROUND: Despite numerous studies in experimental rat small bowel transplantation (SBT), few authors make reference to perioperative analgesia. Recent changes to the Animals (Scientific Procedures) Act 1986 in the United Kingdom have made the use of analgesia in laboratory animals compulsory because pain is unnecessary in the majority of scientific procedures. METHODS: Heterotopic SBT (PVG-->DA) was performed on male rat recipients weighing 220 to 250 mg under isoflurane with a mean anesthetic time of 100 minutes. Recovery from anesthesia was usually within 15 minutes. Analgesia regimens were based on those in common use for other procedures. All drugs were administered in the 30 minutes prior to recovery from anesthesia. Group A received carprofen (2 mg/kg IM or SC). Group B was given buprenorphine (0.05 mg/kg either IM or SC). Group C received paracetamol (10- 30 mg) rectally. An early postoperative scoring system of four criteria was used, giving a maximum (least desirable) score of 16. Sixty transplants were performed, divided between the three groups. RESULTS: In group A animals scored a median of 1 of 16 but all except three recipients died within 3 hours. Those in group B scored a median of 8 of 16, but all animals except one died between 4 to 16 hours after surgery. Group C had a median score of 11 of 16, but there was no early mortality. Postmortem examination excluded technical failures in all but three animals. CONCLUSION: We recommend the use of paracetamol for perioperative analgesia in SBT because of the high mortality associated with other drugs when used in this procedure.

The pre-operative rate of growth of colorectal metastases in patients selected for liver resection does not influence post-operative disease-free survival.

AIMS: To assess the potential association between the change in diameter of colorectal liver metastases between pre-operative imaging and liver resection and disease-free survival in patients who do not receive pre-operative liver-directed chemotherapy. MATERIALS AND METHODS: Analysis of a prospectively maintained database of patients undergoing liver resection for colorectal liver metastases between 2005 and 2012 was undertaken. Change in tumour size was assessed by comparing the maximum tumour diameter at radiological diagnosis determined by imaging and the maximum tumour diameter measured at examination of the resected specimen in 157 patients. RESULTS: The median interval from first scan to surgery was 99 days and the median increase in tumour diameter in this interval was 38%, equivalent to a tumour doubling time (DT) of 47 days. Tumour DT prior to liver resection was longer in patients with T1 primary tumours (119 days) than T2-4 tumours (44 days) and shorter in patients undergoing repeat surgery for intra-hepatic recurrence (33 days) than before primary resection (49 days). The median disease-free survival of the whole cohort was 1.57 years (0.2-7.3) and multivariate analysis revealed no association between tumour DT prior to surgery and disease-free survival. CONCLUSIONS: The rate of growth of colorectal liver metastases prior to surgery should not be used as a prognostic factor when considering the role of resection.

Microbial diversity and activity in seafloor brine lake sediments (Alaminos Canyon block 601, Gulf of Mexico).

The microbial communities thriving in deep-sea brines are sustained largely by energy rich substrates supplied through active seepage. Geochemical, microbial activity, and microbial community composition data from different habitats at a Gulf of Mexico brine lake in Alaminos Canyon revealed habitat-linked variability in geochemistry that in turn drove patterns in microbial community composition and activity. The bottom of the brine lake was the most geochemically extreme (highest salinity and nutrient concentrations) habitat and its microbial community exhibited the highest diversity and richness indices. The habitat at the upper halocline of the lake hosted the highest rates of sulfate reduction and methane oxidation, and the largest inventories of dissolved inorganic carbon, particulate organic carbon, and hydrogen sulfide. Statistical analyses indicated a significant positive correlation between the bacterial and archaeal diversity in the bottom brine sample and NH4+ inventories. Other environmental factors with positive correlation with microbial diversity indices were DOC, H2 S, and DIC concentrations. The geochemical regime of different sites within this deep seafloor extreme environment exerts a clear selective force on microbial communities and on patterns of microbial activity.

Inhibition of chicken liver carboxylesterase by activated carbonyls and carbonyl hydrates.

Identical Kcat values (approximately 40 s-1) are obtained for the chicken liver carboxylesterase catalyzed hydrolysis of phenyl, p-nitrophenyl and o-nitrophenyl benzoates providing support for the involvement of an acyl-enzyme pathway, with the rate-limiting deacylation of a common benzoyl-enzyme intermediate. Chicken liver carboxylesterase catalyzed fragmentation of (E)-benzilmonoxime O-2,4-dinitrophenyl ether shows a pH dependence on a group active in the free base form with a pK'a approximately 5.0. The Ki-pH profile for benzil inhibition shows a dependence on a similar group with a pK'a = 5.4. The reactions between chicken liver carboxylesterase and the hydrated aldehyde, chloral hydrate, have shown this compound to be at once a substrate and potent inhibitor of the enzyme. The kinetics of inhibition are consistent with a mechanism in which the bound hydrate is first dehydrated in a rate-limiting step catalyzed by the enzyme. Nucleophilic attack by the active-site serine on the parent aldehyde produces a hemiacetal adduct. The Ki value for chloral hydrate inhibition calculated from the kinetic analysis (90 nM) compares favourably with the value measured from the steady-state kinetics (87 nM).

New catalytic roles for serine esterases: a 19F-NMR study of the interaction of 3,3,3-trifluoro-2,2-dihydroxy-1-phenyl-1-propanone with chicken liver carboxylesterase.

The reactions of 3,3,3-trifluoro-2,2-dihydroxy-1-phenyl-1-propanone (TDPP) with chicken liver carboxylesterase have shown that this ketone hydrate is not only a potent inhibitor of the enzyme, but also a substrate for a number of enzyme-catalyzed reactions. The kinetics of inhibition are consistent with a mechanism in which the bound hydrate is initially dehydrated in a rate-limiting step catalyzed by the enzyme. Nucleophilic attack by the active-site serine on the parent ketone then produces a hemiketal adduct. However, the slow reactivation (by dialysis) of TDPP-inhibited enzyme indicates that the interaction with this inhibitor is more complex. At equilibrium, a dissociation constant of 2.4 pM was obtained for this interaction. 19F-NMR studies of the enzyme-TDPP complex show that after pre-equilibration, the major adduct is not the hemiketal adduct. It is proposed that this final adduct is a cross-linked adduct formed between TDPP, the active-site serine and the active-site histidine. 19F-NMR studies reveal that chicken liver carboxylesterase catalyses the cleavage of TDPP to yield either fluoride ion or trifluoroacetate, and also the benzilic acid rearrangement of TDPP to alpha-trifluoromethylmandelate. These products have also been identified in model studies of the reaction between TDPP and imidazole.

Computerized telephone assessment of the "concrete" needs of chemotherapy outpatients: a feasibility study.

The feasibility of using a computer-automated telephone outreach system to routinely assess the needs of chemotherapy outpatients was evaluated. The automated intervention was designed as a cost-efficient strategy for assessing patients' needs on a periodic basis so that emerging needs could be identified in a timely way. Ninety-seven chemotherapy outpatients were surveyed at least once over the telephone by a computer in a high-quality, digitally stored voice asking 12 questions regarding the patients' "concrete" needs. Early results of this larger ongoing study, in which patients are scheduled to be called every 4 to 6 weeks for approximately four months, indicated that computer-automated surveys had broad-based acceptance among our outpatients and that patients were able to comply accurately with the survey's instructions. Furthermore, the speech recognition system was found to be reliable, and patients' response patterns to the automated surveys valid. Nonparticipation in this study (28.0%) was not substantially higher than in our previous research within this patient population and neither nonparticipation nor attrition appeared significantly attributable to the automation itself. This method offers the potential for cost-efficient, universal, and ongoing assessment of patient needs, facilitating timely intervention, and efficient use of professional staff.